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rele AN D RADIO REVIEW (161/7 Year of Publication)

No. 484. WEDNESDAY, DECEMBER 5TH, I928. VOL. XXIII. No. 23.

that area and population of a country must be the prin- Editor: HUGH S. POCOCK. cipal factors in deciding upon the power and number of Assistant Editor: F. H. HAYNES. broadcasting stations to which that country is entitled. Editorial Offices: 116 -1x7, FLEET STREET, LONDON, E.C.4 Then the geographical distribution of the country and a . Editorial Telephone: City 947z- (5 lines). consideration of whether the area over which the trans- Advertising and Publishing Offices: missions are to be made is mountainous or otherwise, DORSET HOUSE, TUDOR STREET, LONDON, E.C.4. must be taken into account, and it has even been sug- Telephone: City 2847 (13 lines). Telegrams: Ethaworld, Fleet, London." gested that these factors can be so combined as to provide COVENTRY : Hertford Street. 7eleerams: " Cyclist. Coventry." Telephone: 5210 Coventry. a simple formula from which the rights of every country

BIRMINGHAM : Guildhall Buildings, Navigation Street. can be appraised, and that such a formula will also per- Telegrams. "Aotopress, Birmingham." Telephone: 2970 and 2971 Midland. mit of countries having the choice of a few high -powered MANCHESTER : 260, Deansgate. low-powered ones, without upsetting Telegrams: " Ilusa. Manchester." Telephone: 8970 City (4 line,). stations- or many PUBLISHED WEEKLY. the principle. Subscription Rates : Home, ils. 4d. ; Canada, 17s. 4d. ; Thus far it might be possible to distribute stations with- other countries abroad, iss. 6d. per annum. out serious difficulties were it not for the fact that we Entered as Second Class Matter at New York, N.Y. in addition, the relative efficiencies of As many of the circuits and apparatus described in these pages are covered by have to consider, patents, readers are advised, before making use of them, to satisfy themselves various wavelengths for the purpose of broadcasting. that they would not be infringing patents. The shorter wavelengths of the normal broadcast band, CONTENTS OF THIS ISSUE. whilst enabling more stations to be accommodated, are FADE by no means popular because they have not proved tc EDITORIAL VIEWS 751 AN HOUR WITH A PICTURE RECEIVER. BY "EMPIRICIs1 " 752 be particularly suitable for the purpose, largely on A.C. GRAMOPHONE AMPLIFIER. BY N. P. VINCER -MINTER 755 fading. Wavelengths of a higher order, PROGRAMMES FROM ABROAD...... 761 account of CURRENT TOPICS .. 7d5 found most suitable for broadcasting purposes, are not VALVES WE HAVE TESTED. COSSOR S.G. 220 .. 767 A SAFE H.T. SUrPLY ...... 768 sufficiently numerous to be allotted to all countries, USEFUL DATA CHARTS (Nos. 18 AND 18A) .. 760 BROADCAST BREVITIES ...... 772 although every country may covet them, and when the NEW APPARATUS ...... 774 use of the long wavelengths is considered the difficulty BROADCAST RECEIVERS. GRAVES " VULCAN " 7 \i'0 .. 778 LETTERS TO THE EDITOR ...... 777 immediately arises that it is not possible to accommodate READERS' PROBLEMS., ...... 778 more than half a dozen or so in Europe without mutual interference, so that here another factor arises which has ALLOCATION OF WAVELENGTHS to be taken into consideration in our formula, and is de- FOR BROADCASTING. pendent on the relative efficiencies of different wave- WHEN broadcasting in Europe started there was lengths for broadcasting purposes. practically no machinery of any kind in opera- We have not yet completed the recital of the difficul- tion to control, internationally, the choice of ties, for another consideration has recently been put for- wavebands used by the different countries. At first this ward as claiming the attention of those responsible for mattered very little, for in the wavebands available the distribution of stations. It is that the present system there was plenty of room for a limited number of stations of giving satisfactory broadcast service to urban p6pu - to work, but as more and more stations were put up the lations has had the result of neglecting rural communi- question of mutual interference began to take definite ties, and is both unsatisfactory and unfair ; it has been . shape as one of the most difficult problems requiring to put forward by way of argument that the town -dweller be settled by mutual agreement if broadcasting through- already has at his disposal a surfeit of the amenities of out Europe was to be developed on harmonious lines. civilisation and that his need for broadcast entertainment It is not proposed here to offer another to a number of is far less than that of those who, on account of their tentative solutions of the difficulty which have already location, find broadcasting an important and, perhaps, been put forward by those whose business it is to study their sole form of entertainment and contact with the the problem, but in order that the difficulties may be civilised world. Broadcasting means very much more realised it is, perhaps, of interest to consider what fac- to the isolated units of society than it does to others more tors must be regarded as governing any general agree- favourably situated as far as intercourse with their ment which may be reached as a development of the fellows is concerned, but whether this can be taken into present basis which was agreed at Geneva as providing account to the extent of considering it as a prime factor a provisional solution. It has been generally conceded in the distribution of stations has yet to be decided. A 19

www.americanradiohistory.com w:1191W.IllW91.1ka PIP.15,4l!!

752 Wt@Il@m DECEMBER 5th, 1928. %nOO 1?1101

An Account of Broadcast Picture Reception with the Fultograph. By "EMPIRICIST."

v HE writer, perhaps as a favoured applicant, has received on the apparatus available in this country. A just secured a picture -receiving outfit from the very real difficulty was met with in that the wavelength first batch of Fultograph machines to become used is 1,649 metres, which almost breaks into the high available. The outfit comprises the picture -receiving note modulation of Daventry, and jamming is probable. machine, the rectifying panel with tnilliammeter and Not very hopeful, therefore, were the prospects for the relay, a P.M.4DX valve, connecting leads and plugs, a first night's test in which a picture transmission was to quantity of picture- receiving paper, and a bottle of be received that is normally so completely obliterated sensitising solution. Being identical in its design and by Daventry that its existence is practically unknown operation to the instrument recently described in these in this country.2 In spite of these adverse conditions pages,' no special instructions were sought from the of range and selectivity, it is necessary to create a signal manufacturers. After more than two years' contact with that will unfailingly actuate the relay. To use a frame experimental picture reception little novelty attached to aerial was, therefore, essential, and to this was coupled the inception of this new machine. It was not to be an H.F. amplifier, an H.L.6ro anode bend detector and appreciated merely as a sensation, but rather by the a single L.F. stage with a P625 valve. Critical mani- merit of the results secured. pulation of the frame, the tuning dials, and the volume It is doubtful if many listeners are aware that the control reduced the Daventry transmission to extinction B.B.C. are regularly transmitting pictures by the Fulto- so that a talk which was in progress from the German graph system, or if they are so informed, at what hour station was just audible on the loud speaker. these transmissions are made. Details of the picture broadcasts are not to be found in the programmes pub- Operates with Weak Signals. lished in the B.B.C. official organ or the columns of the To connect up the picture machine was the work of daily Press. These " secret " transmissions are made a few minutes, as all the necessary leads are made up daily from Daventry 5XX at 2 p.m. Listeners finding and terminated on multi -ended plugs. By throwing its this hour inconvenient may have hopes of a week-end switch to " on " it was noted that the modulated signals midday transmission, but will find that Sundays are of the speech transmission produced an average current excepted. Fortunately, an evening transmission is made in the anode circuit of the additional rectifying valve well up by certain of the Continental stations. in excess of 5 mA., the full scale reading of its meter. It should be noted here that the P.M.4DX has a mutual Selectivity an Essential. conductance of approximately 2, which means that were On the day on which the first tests were made with there no resistance into anode circuit a current change the new machine the writer had the opportunity of test- of 2 mA. would be produced for every volt change ing its performance on the inaugural picture transmis- applied to its grid. Actually the output valve of a sions from Konigswusterhausen, which, by the way, receiving set may be handling a voltage swing of 3o or usesthe Fultograph system. Thus, its pictures can be more peak volts, which multiplied ' y its amplification

' First published descriptin.0 of the Fultograph. The Wire- 2 Not to he confused with the Konigswusterhausen transmis leer World, October 24th, 1928. sion on 1,250 metres. A 20

www.americanradiohistory.com DECEMBER 5111, 1928. L7bgD@go 753 WOOFDII0 An Hour with a Picture Receiver.- among the interruptions composing the picture and the factor, probably 5, as well as the ratio of the trans- machine will run on unchecked. former fitted as an input to the rectifying valve of 6 to i, After the warning " Achtung! Achtung! " from the gives rise to a current change enormously in excess of German station a tuning note facilitated the adjust- requirements. A mean current of some 3 mA. only is ment of signal strength, during which period the required to work the Fultograph, so that two -stage L.F. moistened paper was prepared and clipped to the amplifiers are not wanted as an input, while the signal cylinder. Then came a period of silence, during which required to produce audibility from a loud speaker is time the clockwork was released, rotation being held by much in excess of that required for picture reception. the relay. Next a series of properly spaced synchronis- With any given combination of valves, therefore, a ing dots let go the cylinder for three or four successive good picture can be received from a distant station revolutions, indicating everything to be in order. Then whose signals are too weak for loud speaker reproduc- followed the picture. On the first attempt, however, tion. From these observations it is evident that a synchronising was almost immediately lost as a result critical input is called for which, of the relay being released by the in turn, demands a good' volume ' ` mush " that was brought in in control. This control should pre- a foolish endeavour to augment the ferably be independent of the signal strength. The effect was tuning adjustments and might well that a heavy marking occurred on be fitted to the rectifier panel. the left -hand side of the picture.' As synchronising is effected by a It is here suggested that a check - momentary signal which restarts squared pattern tin. in width on

(Left, No. 1) The dark vertical markings are due to interference from 5XX, which has a frequency difference of only 10 kC with Konigswusterhausen. , (Above, No. 2) A less dense picture pro- duced by a weaker signal and in which the Daventry interference has almost disappeared. (Right, No. 3) A radio picture from Paris. The system employed has a different rate of traverse to that provided on the receiving machine, resulting in an elongation of the mage. the cylinder at each rotation, it is obvious that the the edge of every picture would be reassuring to the machine must start in step or its automatic switching user that his machine is running correctly, for the cams will not bring the relay into operation at the right detail of the start of a picture usually affords very little moment preceding the transmission of the dot which on clue. Picture No. z embodies the experience gained each revolution restores rotation. Thus, the cylinder during the former reception, and the black lines which must start right, and the procedure, until it becomes a disfigure it are the record of high- pitched notes from habit, is a little tricky. To switch in the machine too the Daventry transmission. early means that the relay will be actuated by the tail - For picture No. 2 signal st ength was cut down far end of the preceding announcement or tuning note. To switch in too late, that is after the picture has started, ' Reproduced on page 727, Thee Wireless World, November means that the synchronising signal will not be found 28th, 1928. A 2I

www.americanradiohistory.com 754 WfirmDmo DECEMBER 5th, 1928. WopIlt An Hour with a Picture Receiver. - our receiver was adjusted. As a result picture No. 3 below the audibility point, and with no other clue than is elongated. Synchronisation was intermittently lost the picture itself there was a danger of picture recep- during the recording of two subsequent pictures from tion fading out entirely, as evidenced by the lighter the Paris station, the trouble being due to the slight un- portion which is just discernible half -way across. A suitability of their system. The pictures became " line " image, being a readily readable penned marked, and are therefore not reproduced here, but announcement of greeting from Berlin, was the fourth there was no difficulty in identifying the notable per- picture transmitted. sonages they represented. Following a now routine procedure from picture to Now that there is an indication that picture- receiving picture, another piece of paper was prepared with great machines are coming into more general use it is hoped h2ste and clipped in readiness on the cylinder, pending that a British transmission, perhaps even on a normal being set in rotation by an incoming signal. Konigs- broadcasting wavelength, may be arranged at a time wusterhausen had finished, however, yet a slight move- reasonably convenient to the average listener. Quite ment of the tuning dial set our picture receiver going a low power transmission could serve the whole of this on a transmission from another source. This time it country, and in order not to interrupt the normal ser- was Radio Paris giving us a parallel transmission of its vice to listeners, may it be suggested that an all picture celebrities, but unfortunately . the conditions at the transmission from a low power station would do much to transmitter did not quite correspond with those to which develop interest.

INVENTIONS OF WIRELESS INTEREST. The following abstracts are prepared, with the permission of the Controller of H.M. Stationery Office, from Specifications obtainable at the Patent Office, 25, Southampton Buildings, London, W.C.2, price is. each. Piezo Crystal Holder. forming the cone except at three points. to result in a high standard of repro- (No. 277,330.) This method of suspension is stated to duction. Convention date (U.S.A.): Septette ber ensure that a substantial portion of the Patent issued to C. Mahe de Chenal 13th, 1926. vibration is a direct to -and -fro or piston de la Bourdonnais. A crystal holder, especially suitable for action, whilst the remainder of the dia- 0000 phragm vibrates by flexure about the mounting quartz and other piezo oscil- A Battery -receiver Unit. lators, consists of a central screst- ring support. The general pitch of the system is (No. 290,350.) controlled by moving the cone D towards Application date : February 10th, 1927. or away from the resonator or horn H. With a receiver using resistance-capa - The conical diaphragm may be so con- city coupling, the cost of the coupling structed that its thickness increases unit is relatively small by comparison gradually from the periphery to the with that of the H.T. battery. For a centre. The combination of the cone small additional charge the H.T. battery with the shallow horn resonator is stated can therefore be adapted to serve as the actual receiver, by incorporating in it the necessary coupling unit, a few ter- minals, and two or more valve holders. As shown in the illustration, a standard H.T. dry -cell battery is fitted with suit- able terminals T, Ti, with valve holders A protective holder for crystals. V1, V2, and with resistances R, R1, and (No. 277,330.) a coupling condenser C, the latter being embedded in the usual insulating mate- adjusted electrode A surrounded and rial used to fill up the spaces between protected by a cup- shaped electrode B the individual cell units. The outfit may firmly screwed on to a support C of suit- able insulating material. The crystal is mounted upon the central electrode A. The holder protects the crystal from dust and dirt, whilst the effect of temperature variations in . altering the electrode spac- ing, and consequently the effective capa- city of the unit, is minimised.

Patent issued to Westinghouse Elec- tric Co. 0000 Loud Speakers. (No. 290,344.) A high tension battery with resistance Application date : February 9th, 1927. stage incorporated. (No. 290,350.) A conical diaphragm D is mounted inside a shallow horn H so that the comprise both H.T. and L.T. dry -cell resulting sound waves are propagated units, the two battery sections being so directly from the front surface of the designed as to last for an a.pproximatel,- diaphragm, and also by reflection from equal time when fitted with dull -emitter the rear surface. The diaphragm is valves of specified consumption. Loud speaker so designed that a substan- supported peripherally from a rigid tial part of the vibration consists of a Patent issued to the British Thomson ring C by cutting away the material piston action. (No 290,344.) Houston Co., Ltd. A 22

www.americanradiohistory.com DECEMBER 51h, 1928. WñpSIl@@0 755 WoTild

An Interesting Amplifier for Both the Radiophile and the Gramophile. By N. P. V INCER =MINTER.

SINCE most modern receivers are designed so that which at the present moment is attracting a good deal their low- frequency portions may be used as a of attention gramophone amplifier, readers may well ask what advantage will they gain by building a separate ampli- Filament and Plate Current from the Mains. fier. The answer is, of course, that they will gain no Now the amplifier with which we are dealing here advantage whatever, and an amplifier separate from a is designed to operate from A.C. mains of any standard wireless receiver is only useful under special circum- voltage and periodicity, taking both H.T. and L.T. stances. Such a device would be fully justified, how- from the mains, grid bias being derived from a grid ever, even if its only good point was that, being solely battery. The reason why no attempt has been made to an amplifier and therefore possessing no rectifier, the dispense with the grid battery is that it is cheap to pur- chances of obtaining poor quality are greatly lessened, chase and should last very many months. The pro- since undoubtedly the detector is by far the weakest link vision of an extra power rectifying valve and its con- in the wireless receiver from the point of view of quality comitant apparatus for the supply of grid bias would of reproduction, notwithstanding the diode rectifier, increase the initial cost of the amplifier to an absurd

Fig. 1. -The theoretical circuit diagram, CHI, 32 henrys; CH2, 20 henrys; RI, 2 ohms; R2, R :, 50 ohms; R4, R-, 5 megohms; Tt, intervalve transformer; T2, mains transformer ; C,, 2 'nids.; C2, C3, 4 mfds. A 23

www.americanradiohistory.com Wilmboo DECEMBER 5th, 1928. WopIl& A.C. Gramophone Amplifier. - provided. This was left out as it is assumed that figure when the low cost and good service of a grid readers will simply connect the usual flexible cord to battery are taken into account, and, of course, no the primary winding of the power transformer as shown method of batteryless bias, other than the provision of in the diagrams. If desired, however, there is ample an extra valve or metal oxide rectifier, is worth con- space for an ordinary tumbler switch to be mounted sidering. on the baseboard. The flexible wire could then be Although a practical wiring plan and dimensional anchored down permanently to the baseboard by the layout will be found accompanying this article, it should usual small ebonite strip so often used for this purpose. be pointed out that this layout may be departed from with the utmost confidence as the whole apparatus is Indirectly -- heated A.C. Valve as Detector. absolutely stable and hum -free, and, moreover, does Now we come to the great and burning question of not motorboat, except under very great provocation, valves. As most readers know, it is customary to such as would cause the best commercial battery employ indirectly -heated cathode valves in any receiver eliminator (whichever that may be) to do likewise, at or amplifier designed so that its L.T. supply is obtained three speeds simultaneously. The whole apparatus from the electric lighting mains through the medium of may, as a matter of fact, be altered if desired, so that a step -down power transformer. In a battery- operated it will fit into a suit case, or into a suitable recess in receiver, the hot filament and the electron-emitting a console type of gramophone. In this respect it is cathode are one and the same thing, but in the case of even better than the " A.C.2 " receiver, described by A.C. mains it is better for certain reasons and under the writer some time ago in this journal, and the actual certain circumstances to use a valve in which the fila- way it is built up on a baseboard is probably the ment is not required to act also as the cathode. It is . simplest and most straightforward that could be not the intention of the writer to enter into these reasons adopted. If anyone desires to build it up in this form, again here, since he has already done so at some length then the writer would suggest that a wooden cover be in a previous issue of this journal. However, there are made after the fashion of the lid of a sewing machine, circumstances which render the indirectly -heated a recess being cut out, of course, for the ebonite strip cathode valve not only unnecessary but undesirable in holding the input and output terminals and the volume a certain portion of the receiver. control. If this were done, suitable holes should be Now in the first place, even thohgh we are not made in the baseboard and in the sides of the cover describing a wireless receiver, let it he asserted by the t for ventilation purposes. writer with profound emphasis, that as matters stand It will be noticed that no " on and off " switch is to -day no attempt should ever be made to use any but

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www.americanradiohistory.com `¡ :' 4,09Tr i. ° - j -. . - ... r.,"mr_ DECEMBER 3th, :928. WMpgi80 757 WOpIlc. A.C. Gramophone Amplifier. - market consume o.8 ampere at o.8 volt, and for this an indirectly -heated type of A.C. valve a's a grid reason they are usually referred to as " Point Eight " detector. This is a position where any form of directly - valves. There is, however, no magic either in the figure heated cathode valve fails miserably as a rule, and if of o.8 or in the fact that the figure for voltage and by way of exception it should appear to work satis- current is the same. These valves can be obtained factorily, one can confidently anticipate its ceasing to with various characteristics. At the present time power do so at any moment. In an amplifier, however, transformers are obtainable which have both a o.8 and although the indirectly- heated cathode valve gives excel- a 3.5 volt winding, so that either these new valves or lent results, the possibilities of replacing it by a valve the older indirectly- heated cathode valves can be used of the directly- heated type must be considered. If the as desired. In this amplifier a " Point Eight " valve filament of an ordinary o.r ampere type of valve were is used in the first stage ; the writer feels sure that some- fed from raw A.C. a hum would be heard due, among one will enquire why it is not possible to use an other things, to the fact that the filament temperature indirectly-heated valve like the K.L.i in this position. being low, it does not remain constant during one corn- There is, of course, no reason at all against this being

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A general view of the amplifier. plete A.C. cycle, but tends to vary in temperature in done if desired, if the necessary alterations are made step with the A.C. current passing through. By in- in the wiring. The " Point Eight " valve, however, creasing the thickness of this filament and causing it to requires less than one -tenth of the filament wattage take a much heavier current, this disadvantage is greatly demanded by the K.L.r valve, whose consumption is reduced. Suppose, therefore, we built the filament to 2 amperes at 3.5 volts. consume o.8 ampere instead of o.r ampere, what It should be pointed out at this stage that the voltage happens then? amplification given by this valve and transformer stage is quite sufficient to amplify the input signals from The New Point Eight " Valves. average present -day pick -up to a sufficient intensity to We find that the temperature is constant, and the cause overloading if presented to the grid of an ordinary hum tends to disappear, but we have very considerably super-power valve unless the signal input be reduced increased the wattage demanded by our filament. We by use of the volume control. Moreover, the aforesaid can easily restore this by dropping the voltage con- super -power valve will overload before the first valve. siderably, and by doing this we shall gain other This holds good for most pick-ups, with the exception advantages also, due to the resultant short filament. of one or two whose generated E.M.F. is exceedingly There are other advantageous points which cannot be small. considered here, however, as they have already been We have been assuming that our output valve is of brought out in previous articles. Actually, the new the ordinary super -power valve class, but we must directly- heated cathode A.C. valves that are upon the remember that we have to choose an A.C. valve for the A 'S

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wAmmo DECEMBER 5th, 1928. 758 vkpadi

Fig. 3.- The practical wiring diagram, showing the general arrangement underneath the baseboard. It should be strongly emphasised that wires carrying raw A.C. must be twitted together when constructing the amplifier, otherwise a severe hum will make itself et Went.

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DECEMBER 5th, 1928. Mp@il@aT, 759 WopIlú

LIST OF PARTS.

1 Baseboard, 18 x 10 x -'in. 2 Grid Leaks, 5 megohms (Ediswan). 2 Baseboard battens, 10 x 1 x gin. 2 Fixed resistors, 50 ohms (Burndept). 1 Batten to support terminal strip, 6¡ x11/16 Ain. 2 Holders for above (Burndept). 1 Ebonite terminal strip, 61 x3 x'in. I Pair grid battery clips (Bulgin). 1 Power transformer (Model " M" Marconiphone). 1 Grid battery, 161 voUs (Ever-Ready). 1 L.F. choke, 20 henrys (Pye). 3 Wander plugs (Lisenin). 1 L.F. choke, 32 henrys (Pye). 4 Terminais, 2 Pick -up, 2 L.S. (Belling & Lee). 2 Fixed condensers, 4 mfd. (Type " B.T." Dubilier). 1 Length of flex. 1 Fixed condenser, 2 mfd. (Type " B.T." Dubilier). 1 Lamp socket adaptor. 1 Transformer 2.7 : 1 (" Ideal" Marconiphone). 16 Tinned copper wire. 1 Volume control (" Voluvernia," Gambrell). No. 3 Porcelain valve holders (Athol). Sleeving for above. 1 Fixed resistor, 2 ohms (" Pre- set," Igranic). Rubber -covered connecting wire. 2 Grid leak holders ( Bulgin). Wood screws. Approximate cost of parts (excluding valves), 76 17s. 6d. In the " List of Parts " included in the descriptions of THE WIRELESS WORLD receivers are detailed the components actually used by the designer and illustrated in the photographs of the instrument. Where the designer considers it necessary that particular components should be used in preference to others, these components are mentioned in the article itself. In all other cases the constructor can use his discretion as to the choice of components, provided they are of equal quality to those listed, and that he takes into consideration in the dimensions and layout of the set any variations in the size of alternative components he may use.

last stage. Looking at particulars supplied by manu- several theoretical counts, it works excellently in facturers we find that an " output " valve of the in- practice, and the writer often regrets that ordinary com- directly heated cathode type is capable of handling a mercial A.C. transformers with a 6 -volt winding for larger permissible grid swing than the " Point Eight " the purpose of using super -power valves in the output type, and therefore we unhesitatingly choose it. With stage are not more generally obtainable upon the

regard to ' the output obtainable without overloading market, and would express the opinion that it is a matter this valve, the writer regards it as quite sufficient for to which manufacturers might well turn their attention. ordinary purposes without attempting to use two such Readers are warned against thinking that they possess valves in any push -pull arrangement. Confession is a ready -made 6 -volt winding for this purpose in the good for the soul, how- one which is supplied for ever, and the writer ad- heating a U.5 or other mits that he was intending 21S 2 1'2 - rectifying valve. Obvi- to use in the output stage ously the same .. winding an ordinary 4 -volt super- 5 could not be used for both power valve which has purposes. a greater permissible No attempt is made to grid swing, since he was 5/8' enter into constructional details of this amplifier, under the mistaken im- 13/" pression that the trans- 4.c since the work entailed former delivered four full merely consists in assem- volts and not 3.5 volts, 6Y2 bling a few ready-made which is so plainly marked parts on a baseboard in on the instrument. Tests accordance with the de- tails given in the layout. showed that the trans- Fig. 4.- Drilling details of the terminal pane!. Values are as former meant what it said, follows : A, 3!8in. dia. ; B, 5,161n. dia. ; C, 1;8ín. dia., counter- Wiring up should present sunk for No. 4 wood screws. as the 4 -volt valve did not no difficulties. It is im- glow with sufficient brilliance to give any results. The portant, however, that all wires carrying A.C. be writer has no doubt whatever that this arrangement twisted together as indicated in the practical wiring dia- would have worked exceedingly well, because he would gram or a distressing hum will result. It will be noticed mention that he himself uses an amplifier with an ordin- that in the case of the o.8 winding on the transformer ary six -volt super -power valve in the last stage, his a centre tapping is provided by the makers. None is transformer having been constructed for him with a 6- given on the 3.5 -volt winding, but the writer has, as volt winding by a kind -hearted friend possessing much in previous arrangements described by him, picked up skill in transformer design and construction. the centre tapping electrically by shunting the winding In spite of theoretical arguments, which might be with two 5o -ohm fixed resistors in series, the necessary advanced to the contrary, this arrangement does work tapping being made at the junction between these two faultlessly using either a D.E.5A or a P.625. Both aforesaid resistors. A variable potentiometer of the i these valves have 4- ampere filaments, which are quite ordinary wire -wound 400 -ohm type may be used if heavy enough to prevent hum due to temperature desired, but it is totally unnecessary. The fixed variation, which is apparent with o. i valves. Although rheostat in series with the filament of the U.5 valve this arrangement can easily be put out of court on should be adjusted to a position which permits approxi. A 27

www.americanradiohistory.com 76o Wfip@NN DECEMBER 5th, 1928. Wolat A.C. Gramophone Amplifier. - unite these two instruments by a length of " flex," mately two-thirds of the resistance to be in circuit. passing from the pick -up in the gramophone to the Earlier in this article the writer discussed the amplifier in the wireless receiver. At all times this advantage to be gained from a gramophone amplifier length of " flex " would be a menace to the peace of divorced from the wireless receiving set, and was hard the household, since at any moment someone might pressed to find a reasonable causa vivendi. Two trip over it and tread on the cat, this resulting in important reasons have, however, just suggested them- " insulting words and behaviour whereby," as it is selves ; one is that there may exist gramophiles who usually written on the charge sheet, if the writer's are desirous of amplifying gramophone programmes memory does not fail him, "a breach of the peace might only without any thought of wireless reception. The be occasioned." second is the undesirability (in the case of plutocrats This gramophone amplifier is available for inspection possessed of a console type of gramophone in addition by readers at the Editorial Offices of this journal, x16- to a cabinet wireless receiver) of it being necessary to 117, Fleet Street, London, E.C.4.

AMPLIFIER INPUT CONNECTIONS. Detector Output Circuit should be Built into the Receiver, not the Amplifier.

ANY people like to use more than one receiver, with a grid condenser and leak, as indicated in Fig. r ; a either by keeping both permanently in use for 0.005 mfd. condenser and a 2- megohm leak will be suit- M local and distant reception respectively, or by try- able for all cases. ing different types of detector and high- frequency ampli- Universal Connections. fier. In either case, it is both troublesome and expen- sive to employ more than one low- frequency amplifier, If a choke or a resistance is connected in the plate so that it becomes desirable to possess an amplifier that circuit of the detector to which this amplifier is to be attached, a single can be connected to any receiver that is in use at the connection between the terminals moment. If this plan is adopted, then any new receiver marked " Output " and " Input " in Fig. r is all that 1 that may be built need not extend beyond the detector. is required when common batteries are used, while if a transformer is employed " O.S." is connected to the The Detector Difficulty. input terminal of the amplifier, " I.S." being earthed on L.T. - , L.T. + , or H.T. + whichever is most The chief difficulty in such a case is to arrange the con- venient. 'The condenser C is retained in all cases, input connections to the amplifier in such a way to- that it gether with the leak through which can be used after any receiver. the grid bias is applied ; even though it is not required with This difficulty arises because different types of detector a transformer it does no harm, and is retained for the sake of require, for best results, different kinds of coupling be- simplicity in the connections, and to avoid the necessity of switching. tween them and the first valve of the amplifier, so that Fig. 2 shows an elabora- no one coupling can be built into the amplifier and used tion of this system ; here a in all cases. It is logical, therefore, to regard this resistance R of about 20,000 coupling as part of the detector circuit rather than as ohms is connected in series part of the amplifier, and build into to each receiver the with the grid of the first coupling which is most appropriate for the detector con- valve of the amplifier to tained within it. If this is done, the amplifier may begin keep out high- frequency volt- ages, while an iron -core choke of high inductance is connected as indicated for use when it is required to attach the amplifier to a re- ceiver which does not con- tain within itself any means of coupling the last valve to Fig. 2. - Amplifier input the amplifier. In such a case connections when detector output circuit is not incor- the plate circuit of the de- porated in receiver. tector is completed through the choke. A transformer or a resistance might, if desired, replace the choke, but a choke is suggested because of the three it is the only one which gives at least reasonably good results whatever the valve it. Fig 1.- General circuit arrangement of detector followed by that precedes L.F. amplifier. A. L. M. S. A 28

www.americanradiohistory.com DECEMBER 5th, 1928. Wfipdmo 76! Wcoptd

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BARCELONA (Radio Barcelona), Call EAJ1 (344.8 Interval at 11.55 a.m., Time Signal. 12.10, News. metres) ; 1.5 kW-6.10, Orchestral Selections. 8.30, 1.40, Exchange Quotations. 3.0, Illustrated Music Tenor Songs : Un clavell (Pujoll ; La Campana Talk by Dr. Willi. Heinitz. 3.30, Concert of Negro (Saint -Saëns) ; Maig (Toldrá) ; Cançú d'un doble Spirituals : I'm a rolling (Fisher) ; Kingdom vomit' amor (Pujol). 7.0, Recitations by Bartolome Pujol. (Work) Nelly was a lady ; Oh Boys, carry me 7.20, Orchestral Selections : Selection from Rose long ; Old' Black Joe (Foster) Rosa Lee ; Sally, Marie (Friinl) Hungarian Czardas (Michiels) ; Sol- conte up (Buckley) Nelly BIy (Foster) Menagerie; veig's Song (Grieg) ; Glockenstündchen (Kockert). De little oie log cabin in de lane (Hays). 4.30, Re- 7.50, Soprano Songs : Bose endins (Mestres) ; Air quest Programme. 5.30, Dr. S. Landshut, Talk: troni Don Juan (Mozart) Cançó d'Abril (Lamote Is " To Americanise " a Slogan ? 6.0, The Hamburg rte Grignon) ; Air from Hérodiade (Massenet). 8.20, Christmas Market. 6.55, Weather Report. 7.0, Orchestral Selections of French Classical Music : Concert from the Works of Jessel : March, Herz und First Suite from L'Arlésienne (Bizet). 8.40, Sports Hand fürs Vaterland ; Grand Potpourri from The Maid Notes. 9.0 (approx.), Close Down. SATURDAY, DECEMBER 8th. of the Black Forest ; Duet, Im Postkutschkasten, from Des Königs Nachbarin ; Mexican Legend; BERGEN (370.4 metres) ; 1.5 kW. -5.30, Talk for Character Sketch, Spring in Japan ; Es muss ja Girls. 8.0, Programme for Children. 7.0. Orchestral nicht im Mai gleich sein, from Schwalbenhochzeit; Concert. 7.50, Topical Talk. 8.0, Mr. A. Paulsen, All Times are reduced to Greenwich Das ist der Zauber der Liebe from Schwalbenhochzeit ; Palk : The Bergen Dialect. 8.30, Choral Recital. Intermezzo Der Rose Hochzeit ; Intermezzo Siciliano ; 9.0, Weather Report, News and Time Signal. 9.15, Mean Time and are p.m. except Man nimmt ein rosa Blatt zur Hand from Schwalben- Dance Music. 11.0 (approx.), Close Down. hochzeit; where otherwise stated. Auf zug der Stadtwache ; Am Colorado; BERLIN (Königswusterhausen) (1,250 metres) ; 40 Selection from Des Königs Nachbarin ; Unter afrikanis- kW.- 3.30. Programme from Hamburg. 4.30, Herr chem Himmel ; Selection from Die Postmeisterin ; Uhr, Talk : The Everyday Life of an Official. 5.0, Selection from The Maid of the Black Forest ; Flieder Industrial Talk by Prof. Wollt. 5.30, Elementary 8.45, Recital of Songs by Mme. Deby, with M. Illia- und Jasmin ; Serenata di Possilipo; Selection from Spanish Lesson. 5.55, Dr. K. W. Wagner, Talk : s,henko at the Piano. 7.0, Gramophone Selections. The Maid of the Black Forest ; The Parade of the Acoustics. 7.0, " Agricultural " Concert : Über 7.30, " Radio -Chronique." 8.15, Gala Concert. 9.0, Tin Soldiers. 9.30, Weather Report, Newt, Sports allen Gipfeln ist Ruh ( Kuhlau) Heimkehr-florch, Topical Talk. 9.10, Concert (continued). 10.10, Notes and Programme Announcements. 9.45 (approx.) die alten Eichen rauschen (Gelbke) ; Swabian Peasant News and Esperanto Report. 10.20, Orchestral Café Wallhof Concert. 10.50, North Sea and Baltic Dances ; March for Wind Instruments, Hinaus zum Concert from the Palace Hotel. 11.0 (approx.), \Veather Report. Wald (Burman) ; Talk by Heinrich Sohnrey ; Forest Close Down. and Hunting Songs ; Selection for Wind Instruments, HILVERSUM (1.071 metres) ; 5 kW. -9.40 a.m., Nun ruhen alle Wälder. 8.0, Programme from BUDAPEST (556.6 metres) ; 20 kW. -3.45, Time Titus Signal and Daily Service. 11.40 a.m Police Voxhaus. Signal, Weather Report and Sports Notes. 4.0, Announcements. 11.50 a.m., Musical Selections. Orchestral Concert : March of the Gladiators (Fucik) ; 1.40, Musical Programme, relayed from the Tueehinski BERLIN (Voxhaus) (484 metres) ; 4 kW-9.10 a.m., Waltz (Waldteufel) Potpourri (Komzak) ; Selec- Theatre, Amsterdam: Orchestral Conductor, Max Market Prices. 9.15 a.m., Weather Report, News tions (Eulenberg), (a) Musizierende Zigeuner, (b) Tak; Organist, Pierre Palla. and Time Signal. 10.0 Programme of Gramo- 3.40, Italian Lesson. a.m., Schmiedeliedchen, (c) Die Nachtigalle und die Frösche ; 4.40, German Lesson. 5.40, Gramophone Selections. phone Records. 10.30 a.m., Exchange Quotations. The Diplomat (Sousa) ; Spass muss sein (Morena) ; French Lesson. 7.25, Police Announcements. 11.55 Time Signal. Report 6.25, a.m., 12.30, Weather The Phantom B'-igade (Middleton) ; Türkische Schar - 'Concert and Talk, arranged by the and News. 1.0, Programme of Gramophone Records. 7.45, Workers' Wache (Micha±is). 5.40, Talk : The Industrial Radio Society. 10.10, Musical Programme, relayed 2.0, Exchange Quotations. 2.30, Talk by Hans Regeneration of Hungary. 8.15, Sports Notes. 8.30, Royal Picture House, Willibald Tümena. Talk. Reading by front the Amsterdam : Orches- 3.0, 3.30, )'lay from the Studio. 9.15, Tinte Signal, Weather H. de ; Olga tral Conductor, Groot Organist, Joh. Joug. Fuchs- Malzmann. 4.0, Orchestral Concert: Report and News. 9.35, Concert from the Café 11.15 (approx.), Close Down. Selection from The Girl of the Golden West (Puccini) ; Ostende. Waltz (Ziehrer) ; Beau Soir (Debussy) ; Valse WIZEN (340.9 metres) ; 4 kW.-Transmits on 1,862 Romantique (Debussy) ; Grotesque (Lindemann) ; CRACOW (566 metres) ; 1.5 kW. -4.20, Literary Concert of Dance Rose Marie (Fried) Victoria regia, metres from 3.40. 12.10, Trio Music. from Progranuue. 5.0, Programme from Warsaw. 8.0, 2.40, Programme for Children. 5.10, Gramophone ( Künneke) ; Selections from The Rose of Stamboul Miscellaneous Items. 6.20, Scandinavian Tales. Selections. 6.10, Talk by M. Simmons. 6.30, Catholic ¡Fall) ; (Boulanger) ; Overture to La Belle Souvenir 6.45, News. 8.55, Time Signal. 7.0, Review of Report. 6.40, English Lesson. 7.10, Lesson in Dress- liélène (Offenbach) in the Interval, Programme Foreign Politics during the last Week, by Mr. J. making. Talk by M. I.yppens. Announcements. Dr. Henny Moos, Talk: 7.40, 8.0, Concert 5.41, Regula. 7.30, Programme from Warsaw. -9.0, from Ainmerzoden: Choral, Soprano, Saxophone and The Christmas Tree and its Illumination. 5.55, from Concert from a Programme Warsaw. 9.30, Comet Selections ; Talks by Pr. Is. Trienekens and Prof. Talk : Acoustics. Wagner, 7.0, Programme Restaurant. 10.30 (approx.), Close Down. M. Herckenrath, Mayor of Amuierzodeu. from Königswusterhausen. 8.0, Concert of Songs ; 1.5 and Airs ; Air from Orpheus and Euridice (Gluck) ; DUBLIN, Call 2RN (319.1 metres) kW. -1.30, JUAN-LES -PINS (Radio L.L.) (244 metres) 1.5 Von ewiger Liebe ; Sapphic Ode (Brahms) ; Hallelujah Weather Report and Gramophone Selections. 7.20, kW.- 1.0, Orchestral Concert. 9.0, News, Talk for Women ( ; Air Lucrezia Borgia News. 7.30, Selections by Val Vousden (Entertainer). Mozart) from (Donizetti). 8.30, Mme. la Comtesse de Treineuge, The Kreutzer Sonata in A Major Op. 47 (Beethoven). 7.45, Irish Lesson by Seamus O'Duirinne. 8.0, by and Concert. Darce Music. 10.30 (approx.), Close Down. 9.30, News, Weather Report, Time Signal, Sports Students' Union : Academy of Music. 8.30, Pib 10.0, MacAonghusa. Notes and Dance Music. ( approx), Close Down. Uilleann by Seamus 8.45, Star 11.30 7 Concert : Overture by the Augmented Station Or- KALUNDBORG (1,153 metres) ; kW.-Programme metres) ; 1.5 kW. Orchestral Con- (337 metres). -8.30 BERN (411 -3.0, chestra ; Baritone Solos by J. Challoner 'Heaton ; also for Copenhagen a.m., ilforning cert. 3,30, Programme for Children by Fräulein Pianoforte Selections by Maurice Cole ; Dances by Gymnastics. 10.0 a.m., Weather Report. 10.15 a.m., Grety Vogt. Orchestral Concert. Time Talk. 11.0 Chimes from 4.0, 8.29, the Augmented Station Orchestra : Selections by J. Educational a.m., the Town Signal and Weather Report. 6.30, Dr. Zurukzoglu, Challoner Heaton ; Violin Solos by Winifred Small; Hall. 11.5 a.m., Orchestral Concert from Wivel's Talk : are the Aims of Eugenics, and how 2.0, Programme for Children. What are Augmented Station Orchestra ; Maurice Cole ; Restaurant. 2.30, The March they to be realised f 7.0, Symphony Concert relayed Instrumental Duet by Maurice Cole and Winifred Concert : 'furkish (Mozart) ; Overture to from Basle (1,010 metres). 9.0, News and Weather ; Valse brunettes (Ganne) ; Selection Small ; The Augmented Station Orchestra. 10.30, 'faltered from Report. 9.15, Orchestral Concert by the Kursaal News, Weather Report and Close Down. A Masked Ball (Verdi) ; Ave Maria (Schubert) ; Orchestra. 9.40, Dance Music. 11.0 (approx.), Mazurka, Columbine (Lumbye) ; Heise og Weyse ; 4 kW. Pro- Close Down. FRANKFURT (428.6 metres) -2.5, (Larsen) ; Reading by Clara Schwartz ; Paris gramme for Children. 2.55, Talk for the Housewife. March (Gamic; ; Waltz, The Skaters (Walrlteufell,; BRESLAU (322.6 metres) 4 kW. -3.0, Review of : 3.35, Concert Selections (Mascagni), (a) Intermezzo Lilac Time ; Books by Richard Steinnolt. 3.30, Concert of Tenor Selection from (Schubert- Berté) Polka, sinfonico from Cavalleria Rusticana, (b) Cherry Duet, Dina (L'umbye) ; Hungarian Dance, No. i, Op. 0 Solos and Quartet Selections. 5.0, Film Review by from L'Amico Fritz, (c) Ratcliff's Dream from William Hans Baldung. 5.25, Esperanto Talk by Alfred (Brahms) ; March, Under the Star -Spangled Banner Ratcliff ; Songs ; Selection from Iris (Mascagni) ; Talk by Herr v. (Sousa). 4.50, Talk : The Choice of Seeds for the Hanuschke. 5.35, Reinersdor8. from A basso porto (Spinelli) ; Songs; Intermezzo Garden. 5.20, Otto Jucl Jorgensen Talk : Something Shorthand Lesson. 6.50, Herbert Bruner, Talk : 6.20, Intermezzo from Romeo and Juliet (Zandonai) ; The Dawning of a New Era the World in a About Stoves. 5.50, Weather Report. 6.0, News and -Round Selection from La Bohème (Leoncavallo) ; In the Second by Wireless. 7.15, Programme of Old and Exchange Quotations. 6.15, Time Signal. 6.30, Interval, Wireless News and Announcements. 5.10, : New Dances. 9.0, News, followed by Dance Music. Cauillla Perssen, Talk Women in the World of Reading from the Novel, " On Two Planets " (Lass - Business.. 7.0, Chimes from the Town Hall. 7.2, BRÜNN (441.2 metres) ; 2.5 kW.-5.0, German Pro- witz) by O. W. Studtmann. 5.30 The Letter Box. Concert of Indian Verse and Music: Introduction; Lesson by gramme. 8.0, Concert : Overture to The Czar and 6.0, Esperanto W.. Wischhoff. 6.30, Selection from Bhagavadgita ; Temple Hymns, the Carpenter (Lortzing) ; The Nutcracker Suite Advertising Talk. 6.45, Maria Schlee, Talk : A (a) Hymn to Indra, (b) Hymn to Agni, (e) Hymn to Frankfurt League (Tchaikovsky) ; Songs (Grieg) Songs (Brahms) ; Trip to Switzerland by the for Ushas ; The Heavenly Messenger (Kalidasa) ; Folk ; Education. " The Red Robe " -Drama Songs (Liszt) Selection from Lohengrin (Wagner). Adult 7.15, Songs ; Mother India (Dvijendralal Ray) ; Music on (Brieux), followed by Dance Music relayed from 8.45, Programme from Prague. 8.15, " The Pearl Indian Motives ; News. 8.15, Duet Recital (Hansen) : Necklace "- Comedy (Ed. Bass). 9.0, Programme Voxhaus. The Girls of the "Town ; Boating ; Minstrels Waltz ; from Prague. 10.25, Dance Music from the Hotel ; Call HA (in Morse), ; The Lard of Song Grey- weather Dreams; Vaga- Rosenbreier. HAMBURG, (394.7 metres) 4 kW. -9.15 a.m., News. 10.0 a.m., Programme bonds ; Amor. 8.45, Concert of Light Music. 9.45, Music by the Orchestra of the lndustri Restaur- BRUSSELS (508.5 metres) ; 1.5 kW. -5.0, Orchestral of Gramophone Records. 11.10 a.m., Weather Report. Dance Concert from the Arinenonville Tea Rooms. 6.0, 11.15 a.m., Exchange Quotations. 11.30 a.m., ant. 11.0, Chimes from the Town Hall. 11.15 (approx.). Elementary English Lesson. 6.25, English Lesson. Concert relayed from Hanover (297 metres) ; In the Close Down. A 31

www.americanradiohistory.com 762 DECEMBER 5th, 1928. G7opil0 Programmes from Abroad. Music relayed from New York. 12.30 a.m. (Sunday), - Saturday, December 8th. Musical Programme from the Eastman Theatre, KATTOWITZ (422 metres) ; 10 kW. -4.35, Children's Rochester. LO a.m., Musical Programme from the Letter Box. 5.0, Programme for Children. 6.0, Onondaga Hotel, Syracuse. L30 to 4.0 a.m., New York Announcements. 6.20, Talk by Mr. K. Zienkiewicz. Relay. 1.30 a.m., The Park Bench." 2.0 a.m., 6.56, Time Signal. 7.0, Mr. K. Rutkowski, Talk: All Times are reduced to Greenwich Selections by the Adler Quartet with Sonia Essio Impressions of a Journey to Constantinople. 7.30, (Contralto). 2.30 a.m., Selections by a Male Octet. Programme from Warsaw. 9.0, Weather Report and Mean Time and are p.m. except 3.0 a.m., Lucky Strike Programme. 4.0 a.m., Time News. 9.30, Dance Music. Signal, and Dance Music, relayed from Buffalo. 5.0 where otherwise stated. a.m. (approx.), Close Down. KAUNAS (2,000 metres) ; 7 kW.-3.0, Concert: Winter Storm (Fucik) ; Selection (Rebikopf) ; STAMBOUL (1,200 metres) ; 5 kW.- -3.30, Concert Winter (Tchaikovsky) ; Waltz ( Waldteufel). 3.35, 4.30, Market Prices Report. 5.15, Concert of Turkish " Winter in Poetry." 3.45, Talk. 4.30, Announce- Göteborg (416.5 metres), Malmo (260.9 metres), Oster- Music. 7.30, Weather Report and Time Signal. 7.40, (720 metres), (545.6 metres). ments. 5.0, Weather Report and News. 5.15, Agricul- sand Sundsvall -4.0, Vocal and Orchestral Concert : Orchestral Selections, Programme for Children. tural Report. 5.45, Mr. Z. Kuzmickis, Talk : Lithua- Orchestral Selections. 5.0, (a) Overture to Parsifal (Wagner), (b) Mosaïque Talk : The Shorthand -typist. Cabaret nian Literature. 6.15, News. 6.30, Evening Enter- 5.30, 5.45, (Beethoven) ; Songs ; Orchestral Selection, Ballet tainment. Sketch. 6.30, "The Messiah Oratorio (Handel), Suite from (Trémisot). 9.0, News and relayed from a Church. 8.15, News and Weather Announcements. 9.10 (approx.), Close Down. LAHTI (1,522.8 metres) ; 35 kW. -4.0, Vocal and Report. 8.45, Topical Talk. 9.0, Dance Music. Orchestral Concert : Parola Marche ; Selections 12.30 a.m. (approx.) (Sunday), Close Down. STUTTGART (379.7 metres) ; 4 kW. -3.35, Programme (Sibelius), (a) Valse triste, (b) Berceuse, (e) Suite from Frankfurt. 5.0, Time Signal and Weather Report NAPLES, Call INA (333.3 metres) ; 1.5 kW. 99; Songs (Merikanto). 4.35, Talk. 5.15, 7.30, 5.15, Herr Schwaebsch, Talk : The Trade Mark as a Op. Wireless Notes. Announcements. News. Finnish Songs (Merikanto) ; Finnish Songs (arr. 7.40, 7.50, Commercial Weapon. 5.45, Talk by Dr. Kümmerlen. Kauppi). 5.40, Talk. 6.0. Concert. 7.55, Harbour Notes. 8.0, Time Signal. 8.2, Orches- 8.15, Talk by Bernd Isemann. 6.45, Time Signal and tral Concert, followed by Two Comedies. 8.0, Review Sports Notes. 7.15, Folk Song Stories : Kurt Arnold LANGENBERG (468.8 metres) ; 20 kW.- Programme of the Week. 9.50, News. 9.55, Calendar and Pro- Findeisen (Elocutionist), assisted by Vocal Quartet. gramme Announcements. 10.0 (approx.), Dance Music also for Aix -la- Chapelle (400 metres), Cologne (283 8.15, Concert : The Rhine ; On the Banks of the from the Close Down. metres) and Münster (250 metres). -8.0 a.m., Chimes. Trocaderu. 10.30 (approx.), Rhine, from the Rhineland Suite (Luling) ; Wenn Recital. Labour 8.5 a.m., Catholic Morning 9.35, OSLO (481.5 metres) ; 1.5 kW.-Programme relayed über dem Rheintal der Himmel blaut (Luling) ; : of Exchange Report. 10.10 a.m., Talks The Choice by (4:34.8 metres), Hamer (555.6 metres), Rheinfahrt (Martin Greif) ; Mein Heimatland, o du Hans Fredriksstad Careers. 11.0 a.m., Organ Recital by Prof. Notodden (411 metres), Porsgrand (500 metres), and herrlicher Rhein ; Frühling am Rhein ; Folk Song, Bachem. 12.5, Orchestral Concert : Carnival Overture Rjnkan (448 metres). -5.0, Programme for Children. Der schönste Bursch am Rhein ; Auf dem Rhein (Dvorak) ; Angelus (Micheli) ; Im Rosengarten 6.0, Birthday Greetings. 8.15, Weather Report and (Brentano) ; So singt man ans Rhein (Haseloff) ; Mendelssohn ( Urbach) ; Nordisches Capriccio News. 6.30, Readings. 7.0, Time Signal. 7.2. Variety Wein vom Rhein ; Im Rheingau (Reyling) ; Folk (Donisch) ; Waltz, Red Roses (Lehár) ; Selections Concert. 8.30, Weather Report and News. 8.45, Song, Eislein von Caub ; Das Herz am Rhein (Hill) ; from the Works of Suppé (Rhode) ; Little Grand- Topical Talk. 9.0, Concert (continued). 10.0, Dance Paraphrase, Die Lorelei ; Legend, Der Spielmann in mother (Langer) ; Tango, Erinnerung an Neapel Music from the Grand Hotel. 11.0 (approx.), Close Mainz ; Ballad, Two Brothers (Heine) Rhenish (Michael) : Boston, Gedicht (Finch). 2.40, Herr P. Down. Humour ; Beim Rheinwein (May) ; Reich' mir den Brills, Talk on Wireless Technology -Self- Induction in Becher, du Kind am Rhein ! ; Schunkellied ; Folly PARIS (Ecole Supérieure), Call FPTT (458 metres) ; Direct and Alternating Current Circuits. 3.0, Rev. and Frolics ; Ein rheinisches Mädchen ; Crossing the 0.5 kW. -6.30, " Radio Journal de France." Phillips, Talk : The Battleground of Life. 8.20, Talk 8.0, Cologne Rhine Bridge by Night, Poem ; Vater Rhein, M. Geville. Legal Concert Adelbertha Gerhards. 3,40, Reading Talk by 8.15, Talk. 8.30, du herrlicher Strom (May) Strömt herbei, ihr Volker- for Women by arranged by the Union des Grandes Association. Life of Butterflies " ( Schnack). 4.0, scharen ; News, followed by Dance Music from from " The Followed by News, Time Signal and Weather Report, Fegeler Felkendorf, Talk : Time, Modes and Man. Voxhaus. English Lesson by Prof. F. Hase. 4.45, Orchestral Dance Music from the Coliseum de Paris. 12.0 Mid- 4.20, Close Down, TOULOUSE (Radiophonie du Midi) (389.8 metres) ; (Glinka) ; night (approx.), Concert : Overture to Russian and Ludmilla 8 kW.-12.45, Concert. 8.0, Exchange Quotations for Pianoforte and Orchestra Tower), Call FL (2,650 5 Ukrainian Rhapsody PARIS (Eiffel metres) kW.- and News. 8.30, Instrumental Concert : Selections ; Poem, Stenka Razin (Liapunoff) Symphonic 5.0, Pasdeloup Concert. 7.10, Weather Report. 7.30, from Peer Gynt (Grieg) ; Selections from I Pagliacci Dr. Zbinden, Talk : Intel- (Glazounoff). 5.30, Ham " Le Journal Parlé." (Leoncavallo) ; Selections from Hérodiade (Massenet) before lectual Problems of America. 5.50, Canaries Pianoforte Solo, Turkish March (Mozart) ; 'Cello Solo. on the Occasion of the Canary Show PARIS (Petit Parisien) (340.9 metres) ; 0.5 kW.- the Microphone, 8.45, Gramophone Selections, Talk, News and An- Minuet (Mozart) ; Selections from The Barber of at Düsseldorf. 6.15, Prof. Honigsheim, Talk : Social ; nouncements. Concert : to Seville (Rossini) Mandoline Selections, (a) Les Problems of a Large City. 8.40, Prof. von der Leyen, 9.0, Overture The Pearl of Brazil (David) , Selection from La Dame Blanche Millions d'Arlequin (Drigo), (b) Songe d'amour apres Talk : Fairy Tales of World Literature. 7.0, Variety le bal (Czibulka), (c) La vie heureuse (Schrammel), by News, Sports Notes, Orches- (Boieldieu) ; Overture to the Suite in D (Bach) ; Programme, followed (d) Gavotte ; Finale from the Eighth Symphony in F (Beethoven) ; Louis XIII in the Interval, Time Signal. tral Selections and Dance Music. 12.0 Midnight 10.15, North News. Petite Suite (Buster) Dance (Debussy) ; La Reine African 10.30 (approx.), Close (approx. ?, Close Down. Fiamette (Leroux) ; News in the Intervals. Down. metres) ; 4 kW. -3.30, Orchestral LEIPZIG (365.8 -Paris), Call CFR (1,750 VIENNA (517.2 metres) ; 15 kW. -2.15, Photo - Concert. 4.45, Wireless News and Talk. 5.20, Weather PARIS (Radio metres) ; 6 kW.-12.30, Concert of Gramophone Selections: telegraphy Transmission. 2.45, " Pechvogel und Report, Time Signal and Labour Market Report. Glückskind," Play for Children Orchestral Selection from L'apprenti sorcier (Dukas) ; (Blachetta). 3.30, 5.30, Programme from Konigswusterhausen. 8.0, -Orchestral Selection, Le Carnaval des animaux (Saint - Orchestral Concert, by the Dostal Orchestra : Prelud' Josef Greti, Talk : Psycho -Analysis. 8.30, Dr. Fritz Saens) ; Tristesse (after a Study by Chopin) Sung in from Eva (Lehár) ; Waltz, Transactionen (Jos. Reuter, Talk : Music as a Profession. 7.0, Concert. : Selection ; Russian by Mmes. Birse, Etshova and M. Kondratieff ; Strauss) from Manon (Massenet) Violin " Comic Old Ladies in " ; Katisha's Song Operetta Take in the Sun, Hang out the Moon, by the Singing Solo by Herr Willi Boskovsky, Legende (Wieniawsky) ; from The Mikado (Sullivan) ; Song from Don Cesar Second (Liszt) ; Sophomores ; Portuguese Guitar Duet, Farlo Corrido ; Hungarian Rhapsody Blumengeflüster ; (Dellinger) ; Songs from The Gipsy Baron (Strauss) (von Blois) ; ; Chilly Porn Porn Pee by Ray Starita and his Orchestra ; Potpourri, Pikante Blätter (Komzá4c) Duet from As Once in May (Kolb) ; Olympia's Song Selection from " Good News " by Fred Rich and his Schlussmarsch (Ertl). 6.15, Concert of Chamber from Donna Juanita (Suppé) ; Song from A Night in Orchestra ; Noche de Nieve by the Lucchesi Tango Music : Concerto in E Minor (Nardiui) ; Andantino Venice (Strauss) Duet from Bub oder Mädel (Graních- ; Orchestra ; News in the Intervals. 2.0, Market Prices (Martini) Tempo di Menuetto (Pugnani) Sonata for : Gr( (Lincke) ; from staedten) Duet from -Gri Duet and Religious Information. 3.45, Dance Music by the Horn and Pianoforte (Beethoven). 8.15, Franz Karl Die gold'ne Meisterin (Eysler) ; Duet from Der Ober - Joss Ghislery Symphonians ; News in the Intervals. Ginzkey in Selections from his own Works. 7.20, : Song from Gasparone (Millöcker), steiger (Zeller) 7.0, Agricultural Report. 7.30, Pianoforte Lesson. "Auf Befehl der Herzogin," Operetta -Idyll in Three 8.0, Robert Neumann reads from " Jagd auf Menschen Acts (Granicbstaedten) ; followed by Phototelegraphy 8.0, Talk : The Sahara, a Marvellous Sanatorium, und Gespenster " (Neumann). 9.0, News, Sunday followed by Market Prices and News. 8.15, Concert: Transmission. Programme Announcements, and Sports Notes. Dramatic Programme, Melodies, Dance Music by the 9.30, Dance Music relayed from Voxhaus. 11.30 VILNA (435 metres) ; 1.5 kW. -4.45, News in Joss Symphonians ; News in the Intervals (approx.), Close Down. Ghislery Lithuanian. 6.0, Programme from Warsaw. 6.0, 1.5 kW. Talk for Women by Mme. Ela Buncler. 6.25, Art Tall: Call EAJ7 POSEN (344.8 metres) ; --415, Talk on MADRID (Union Radio), (375 metres) ; Scouts. 4.30, Talk by Mr. Stanislas Stacherski. 5.0, by Prof. J. Klos. 6.50, News and Time Signal. 7.0. 3 kW. Chimes, followed by Sextet Concert : Programme from Programme 7,0, Chamber Music : Trio for Pianoforte (Haydn) ; Warsaw. 7.30, in Sinfonia de zarzuelas (Barbieri) ; Selection from Sonata in A Major, for Violin (Beethoven). 8.0, Prof. Celebration of the First Anniversary of the Vilna The Mastersingers (Wagner) ; La Tajadera (Barrera) ; Stephan Papee, Talk : Antoinette Hoffmann. 8.25. Broadcasting Station. 9.0, Programme from Warsaw. Interlude by Luis Medina. 8.0, Dance Music relayed English Lesson by Dr. Arend. 6.50, Talk for Women 10.30 (approx.), Close Down. from the Alkázar. 8.25, News and Announcements. by Mme. Swidzinska. 7.10, Economic Report. 9.45, Market Prices Report. 10.0, Chimes, followed by 7.30, WARSAW (1,111 metres) ; 10 kW. -4.30, Talk by Operetta Relay from Warsaw. 9.0, Time Signal and Prof. Moscicki. 4.45, Announcements. 5.0, Pro- " La Calesera " : Musical Play (del Castillo and Román, News. 9.30, Cabaret Programme. 11.0, Concert Music by Alonso), followed by News and Annoúnce- gramme for Children. 6.0, Miscellaneous Items. arranged by La Maison Philipps. LO a.m. .(approx.) : ments. 12.30 a.m. (approx.) (Sunday), Close Down. 8.20, Mr. Kolodziejczyk, Talk The Bay of Biscay. (Sunday), Close Down. 6.45, News. 6.56, Time Signal. 7.0, News. 7.5, Call 1MI ; 7 kW. MILAN, (549 metres) 7.15, Talk, PRAGUE (348.9 metres) 5 kW. -3.20, Talk. 3.30, " Radio -Chronique," by Mr. M. Stepowski. 7.30, News and Time Signal. 7.32, Variety Concert: Concert. 4.30, Talk. 4.40, Talk by Dr. Seracky. 5.0, Relay of an Operetta ; in the Interval, Theatre Notes. Quintet Selections, (a) Overture to The Bohemian 9.0, Aviation Notes and Weather Report. 9.6, News. Concert of Popular Music. 6.45, Ing. Svoboda, Talk : Girl (Balte), (b) Suite from L'Arlésienne (Bizet); The Education of the Public by Wireless. 7.0, Cabaret 9.20, Police Announcements and Sports Notes. 9.30, Talk The History and /Esthetics of Music ; Soprano Programme. 8.15, Third Act of " The Pearl Fishers " Dance Music from the Oaza. 10.30 (approx.), Close Songs ; Sonata in E Minor for Violin and Pianoforte (Bizet) relayed from Bratislava (300 metres). 9.0, Down. Q(Bazzini) Relay from the Convegno ; Reading ; Time Signal and News. 9.25, Dance Music from the 1 Concert uintet Selections, (a) Serenade to May (Siede), (b) ZURICH (588 metres) ; kW. -3.0, from the Hotel Rosenbreier, Bruno. Carlton Elite Hotel. 4.15, Accordion Selections. Serenade to Pierrot (Burgmein) ; Soprano ; Songs 4.45, Weather Report and Exchange Quotations. Sonata for Violin and Pianoforte (Franck) ; Quintet ROME, Call 1RO (447.8 metres) ; 3 kW. 7.10, Time (a) from Talk. Selections 5.0, Selection from new Gramophone Records. 6.0,E Selections, Selections André Chénier (Gior- Signal and Topical 7.45, from Opera, Chimes from Zürich Churches. Time Signal dano), (b) Invitation (a) (b) 2 the 6,15, to the Waltz (Weber). 9.56, " The Huguenots " (Meyerbeer), Act of " The and Weather Popular Pro- News, followed by Relay of Tzigane Music from the Barber of Seville " (Rossini). 9.50, News and Close Report. 6.20 (approx.), Fiaschetteria Toscana. 10.45 (approx.), Close Down. Down. gramme. 7.15, Variety Concert : Songs, Selections by 1 imperli (Entertainer), and Orchestral Music. 9.0, MOTALA (1,380 metres) ; 30 kW.- Programme also SCHENECTADY, Call 2XAD and 2XAF (2L96 and Weather Report and News. 9.10, Gramophone Selec- for Stockholm (454.5 metres), Böden (1,190 metres), 31.4 metres) ; 3U kW. -12.0 Midnight, Phil Spitalny's tions of Dance Music. A 32

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Programmes from Abroad. by Teddy Petersen ; in the Interval at 11.0, Town - SUNDAY, DECEMBER 9th. Hall Chimes, relayed from Copenhagen. 11.80 BARCELONA (Radio -Barcelona), Call EAJI (344.8 (approx.), Close Down. metres) ; 1.6 kW.-11.O a.m., Cathedral Chimes Transmission. 11.5 a.m., Meteorological Report for KATTOWITZ (422 metres) ; 10 kW. -9.15 Europe and Spain. 1.30, Concert of Trio Music ; All Times are reduced to Greenwich Relay of Divine Service. 10.56 a.m., Time Signal. Gramophone Records in the Intervals. 2.45 to 5.30 11.0 a.m., Meteorological Report. 11.15 a.m., Concert (approx.), No Transmssion. 5.30 (approx.), Musical Mean Time and are p.m. except of Popular Music by the Studio Quartet. 1.0, Religious Programme; Agricultural Market Prices andlExchange Address. 1.20 and 1.40, Two Agricultural Lectures. Quotations in the Intervals. 8.0 to 8.20, Lecture, where otherwise stated. 2.0, Meteorological Report. 2.15, Transmission of arranged by the Catalonian Institute of Agriculture the Warsaw Philharmonic Orchestral Concert. 5.0, at San Isidro. 8.20, Musical Selections by the Station Musical Programme. 6.0, Various Announcements. Orchestra. 8.40, Sports Notes and Bulletin. 9.0 6.20, Half -an -Hour of Humour, by Prof. St. Ligon. (approx.), Close Down. CORK, Call OCI{ (400 metres) ; 1.5 kW. -8.30, 8.56, Time Signal. 7.0, Talk. 9.0, Meteorological Concert of Vocal and Instrumental Ma=ic : Nora Report and Weather Forecast, 1.5 Press Review aid BASLE (1,010 metres) ; kW-Programme relayed O'Sullivan (Contralto). 11.0, National Anthem and Sports Notes. 9.30, Dance Music Programme. 10.30 from Bern, 7.0, Concert. 8.45, Late News and Weather Report and Forecast. 11.15 (approx.), (approx.), Close Down. Announcements and Weather Report and Forecast. Close Down. 9.15 (approx.), Close Down. KAUNAS (2,000 metres) ; 7 kW. -2.80, Children's CRACOW (586 metres) ; 1.5 kW. -9,15 a.m. to 10.45 Corner. 4.0, Talk by J. 6.30, Concert or BERGEN (370.4 metres) ; 1.5 kW. -9.30 a.m., Relay a.m., Relay of Cathedral Service. 10.58 a.m., Relay Outside Relay. 9.30 (approx.), Close Down. of Morning Service. 11.30 a.m., Weather Report and of the Fanfare from the Church of Notre Dame, Forecast and General News Bulletin. 7.0, Concert by followed by Time Signal and Meteorological Report. KÖNIGSBERG (303 metres) ; 4 kW. Programme the Bergen Wireless Orchestra. 7.50, A Chat on 11.10 a.m., Relay from Warsaw. LO and L20, Two relayed by Danzig (272.7 metres). -8.0 a.m., Morning Current Events. 8.30, Musical Recital : Arensky's Lectures for Farmers. 1.40, Agricultural Bulletin by Service with Choral and Instrumental Selections and Trio for Violin, 'Cello and Pianoforte, by Mrs.Bonnevie, Dr. St. Wasniewski. 2.15, Concert relayed from Address. 10.0 a.m., (Königsberg only), Weather Report Herr Schuster and Herr Müller. 9.0, Weather Report Warsaw. 4.30, Talk. 5.0, Programme from Warsaw. and Forecast. 10.15 a.m. (approx.), Musical Pro- and Forecast, Late News Bulletin and Time Signal. 7.30, Evening Concert devoted to Light Music rendered gramme. U.55 a.m., Relay of the Time Signal from 9.15, Dance Music. 11.0 (approx.), Close Down. by the Mandoline Orchestra accompanied by Mr. Leon Nahen, followed by Weather Report and Forecast. Hoffmann ; Vocal Items by Mme. St. Kopff. 9.0. 7.0, Alpenkönig itnd Menschenfeind," a Drama of BERLIN (I{önigswusterhausen) (1,250 metres) ; 40 kW. Transmission from Warsaw. 9.30, Relay of. Musical Men and Spirits, by Ferdinand Raimund, adapted for -7.55 a.m., Chimes, relayed from the Garrison Church, Programme from a Restaurant. 10.30 (approx.), the Wireless by Hans Bodenstedt, Music by Hermann Potsdam. 8.0 a.m., Sacred Recital with Sermon, Close Down. Erdlen. 9.10, (approx.), Late News Report and Sports relayed from Voxhans, followed by Chimes from Bulletin. Berlin Cathedral. 10.30 a.m. (approx.), Concert DUBLIN, Call 2RN (319.1 metres) ; 1.5 kW. -8.30 Programme from Voxbaus. 3.0, Talk. 3.30, Relay of to 11.15 (approx.), Programme relayed from Cork. LAHTI (1,522.8 metres) ; 35 kW.- Programme also Musical Programme from Wallace. 5.0 to 7.0, Pro- 8.30, Concert of Vocal and Instrumental Music, Violin for Helsingfors (375 metres). 7.0 a.m., Relay of gramme of Talks, arranged by the " Deutsche Welle," Solos by Winifred Small. 11.0, National Anthem and Church Service. 9.50 a.m., News from the Press. followed by Relay from another German Station. Weather Report. 11.15 (approx.). Close Down. 10.5 a.m., Concert. 10.50 a.m., Weather Report and 9.15, Late News and Announcements and Sports Time Signal. 11.0 a.m., Relay of Church Service in of Music. Swedish. 3.0, Concert by Lahti Wireless Notes. 9.30, Programme Dance 11.30 FRANKFURT (428.8 metres) ; 4 kW.- Programme the Orchestra. (approx.), Close Down. relayed by Cassel (252.1 metres). 7.30 a.m. to 4.57, 'Time Signal and Weather Report and Forecast. (approx.), Morning Recital and Address. 5.10, Concert by the Wireless Orchestra : Overture to BERLIN (Voxhaus) (484 metres) ; 4 kW. a.m.+ 8.30 a.m. 7.55 12.0 Doon, Transmission, arranged by the Wiesbaden William Tell (Rossini). 7.15, Concert by the Station Relay of Potsdam Garrison Church Chimes. 8.0 a.m.. Literary Orchestra with Soloists. 7.45, General News Bulletin Sacred Recital of Choral and Instrumental Music, with Agricultural Institute. 7.30, Musical or Programme. 9.30 (approx.), Dance Music. 11.0 given in Finnish. 8.0, News Bulletin in Swedish. Sermon in the Interval, followed by Chimes from 8.30 (approx.), Close Down. Berlin Cathedral. 10.30 a.m. (approx.), Concertjrom (approx.), Close Down. the Grosse Schauspielhaus. Elementary Morse LANGENBERG (488.8 metres) ; 20 kW.- Programme 1.0, HAMBURG, Call HA (in Morse) (394.7 metres) ; Talk. Concert. Musical also for Aix (400 metres), Lesson. 3.0, 3.30, 4.0, or 4 kW.- Logramme relayed by Bremen (272.7 metres), -la- Chapelle Cologne (283 Literary Programme. Talk. Concert Pro- metres) and Minster (250 metres). -8.45 Boxing 6.0, 7.0, Hanover (297 metres) and Kiel (254.2 metres). - a.m., gramme. 9.16, Meteorological Report ; Time Signal, 7 25 a.m. Time Signal. 7.30 a.m., Weather Report, Lesson, by Dr. Ludwig Bach. 7,5 a.m., Alfred Dor- Sports Notes, and Late News and Announcements. followed 6y General News Bulletin. 7.50 a.m., Talk mans : Extracts from the Programme of the Week 9,80, Programme of Dance Music. 11.30 (approx.), on Economic Questions. 10.0 a.m. (for Hamburg, in Esperanto. 7.15 a,m., Music Lesson. 7.35 a.m. to Close Down. Bremen and Hanover), Technical Talk. 11.55 a.m., 7.55 a.m., Lesson in Esperanto. 8.0 a.m., Sacred Time Signal, relayed from Nauen. 12.5 (for Hamburg Recital of Music and Sermon. 12.0 Noon, Musical (411 metres) ; 1.5 kW.--9.30 10.30 BERN a.m. to a.m., and Kiel), Musical Programme. 12.5 (for Bremen), Programme. 3.30, Concert of Orchestral Music. 6.45, Protestant Sermon. 12.0 Noon, Time Signal and : Instrumental Music. 12.5 (for Hanover), Gramophone Sports Notes. 7.0, Evening Concert " The Marriage Meteorological Report. 12.5, Orchestral Concert by of Figaro," Opera (Mozart) ; Late News and Announce- the Linder and Meyer Orchestra. Time Signal Records. 1.0, Children's Corner, by Funkheinzel- 6.29, mann. Concert. 3.0, Musical or Literary Pro- ments, Sports Bulletin and Programme of Light and Weather Report and Forecast. 6.30, Reading or 2.0, Music. 11.0 (approx.), Close Down. Talk. 8.45, Sports Notes, Late News and Announce- gramme. 8.30, Talk on Sport, arranged by the Ham- School of Physical Training. 8.40, Sports News. ments and Weather Report and Forecast. 9.0, burg LEIPZIG (365.8 metres) ; 4 kW.- Programme relayed 6.55. Weather Report. 7.0, Concert or Play. 9.30, by Dresden (275.2 metres). Relay of Organ Musical Selections by the Kursaal Orchestra. 9.40 Late News Bulletin, by 7.30 a.m., (approx.), Close Down. Weather Report and followed Recital. 8.0 a,m., Vocal and Instrumental Concert. Light Music. 10.50 (for Hamburg, Bremen and Kiel), Talk. 11.0 a.m., Concert. Musical or Report for the North Sea and Baltic. 10.30 a.m., 3.0, BRESLAU (322.6 metres) ; 4 kW.- Programme Weather 11.0 Literary Programme. 4.0, Concert. 5.30, Talk. relayed by Gleiwitz (::).7 metres).-8.15 a.m., Relay (approx.), Close Down. 6.30, Concert or Play. 8.0 Stories of East Prussia, of Chimes from Christ Church. 10.0 a.m. (approx.), read by Martina Otto -Morgenstern. 9.0, Sports Recital of Sacred Music with Sermon. LO, Guessing HILVERSUM (1,071 metres) ; 5 kW. -12.30 (approx.), Notes. 9.30, Dance Music, relayed from Berlin. Competition. L10, Talk or Literary Programme. Musical Programme. 2.10, Concert of Orchestral 11.30 (approx.), Close Down. 1.35, Notes for Chess Enthusiasts. 2.0, Children's Music, relayed from the Amsterdam Concert Hall. Programme, Fairy Rates by Friedrich Reinicke. 3.40 Musical Programme. 7.40, Weather Forecast, LYONS (Radio Lyon) (291 metres) ; 1.5 kW.- 2.30, Agricultural Lecture. 7.15, Evening Entertain- News and Sports Notes. 7.50, Concert, including a 7.30, " Le Journal Parlé " : News, Press Review, ment with the collaboration of Mary Wurm- Meysen- Mass by Schubert. 10.40 (approx.), Close Down. Amusements Chronicle and Announcements. 8.0, berg, Hermann Zanke and others. 9.0, Late News and Concert of Instrumental Music, with the collaboration M. Announcements. 8.80, Dance Music. 120 (approx.), HUIZE:I (340.9 metres) ; 4 kW.- Transmits from of Mme. Ducharne (Pianist), Camand (Violinist), Close Down. 3.40 on 1,85.2 metres. -8.5 a.m., Relay of Divine and M. Testanière ('Cellist). 9.0 ( approx,), Close Service and Sermon. 12.10, Concert by the Katholieke Down. BRUSSELS (508.5 ; 1.5 kW. Light metres) -5.0, Radio Ornroep Trio. 1.10, Talk. 1.40, Talk. 2.10, (Union Radio), Call EA J7 (375 metres) ; Music. Children's Corner. Concert of of MADRID 6.0, 6.30, Trio Concert. 5.30, Relay Evening Service from 3 kW.-Programme relayed by Salamanca, EAJ22 Music. 7.30, La Radio -Chronique. 8.15, Orchestral Bodegraven ; Sermon by the Minister, the Rev. G. A. (405 metres). -11.30 a.m., Programme by the Muni- Concert. 10.10, News from the Press. 11.0 (approx.), Pott, on the Text from St. Luke, Chap. 15, Verses cipal Band, conducted by Maestro Villa, relayed from Close Down. 8-10 ; Voluntaries by the Organist, Mr. v. d Vliet. El Retiro. 2.0, Chimes and Time Signal. 2.5, Concert 7.50 (approx.), Orchestral Concert. 10.25, Choral BUDAPEST (556.8 metres) ; 20 kW. -8.0 am., Programme of Light Music by the Station Orchestra, Epilogue, conducted by Mr. Jos. H. Pickkets. 10.40 with Item by Luis Medina in the Interval. 3.30 to General News Bulletin and Talk for Women. 9.0 (approx.), Close Down. a.m., Relay of Sacred Service and Sermon. 1L30 a.m. 7.0, No Transmission. 7.0, Chimes. 7.5, Concert of (approx.), Musical Programme. 2.30, Talk for Farmers. Sextet Music : Selections from La alegria de la huerta 3.15, Concert. 6.30 (approx.), Concert or Relay of an KALUIIDBORG (1,153 metres) ; 7 kW.- Programme (Chueca). 8.0, Programme of Dance Music by the Opera. 9.45, Dance Music. 10.30 (approx.), Close also for Copenhagen (337 metres). -9.0 a.m., Divine Palermo Orchestra from the Alkazar. 8.30 to 10.0, No Down. Service, relayed from Copenhagen. 10.30 a.m. to Transmission. 10.0, Chimes and Time Signal. 10.5, 10.40 a.m. (Kalundborg only), Weather Forecast from Concert by a Regimental Band. 12.0 Midnight, COLOGNE (283 metres) ; 4 kW.- Programme also for the Meteorological Institute. 12.0 Noon to 12.25, Chimes, followed by Programme of Dance Music by Aix-la- Chapelle (400 metres), Langenberg (468.8 Lesson in German, arranged by " Radiolytteren." the Palermo Orchestra. relayed from the Alkazar. metres) and Minster (250 metres). -6.45 a.m., Self 12.30, Lesson in French, arranged by " Radiolytteren." 12.30 a.m. (approx.) (Monday), Close Down. Defence. Lesson. 7.5 a.m., Review of the Programmes 1.0, Divine Service Relay from a church in Copenhagen. of the \ \'eek in Esperanto. 7.15 a.m., Lute or Guitar 2.30, Orchestral Concert. 4.30, Programme for MILAN, IMI (549 metres) ; 7 kW. -9,0 a.m., Opening Lesson by Oily Wirtz Koort. 7.85 a.m., Esperanto Children. 5.0, Time Signal and Chimes. 5.50 Signal and English Language Lesson. 9.30 A.M. te Class by Alfred Dormans. 9.0 a.m., Sacred Festival (Kalundborg only), Weather Report and Forecast 10.0 a.m. Concert of Religious Music, with Vocal and and Address. 12.0 Noon, Musical Programme. 3.80, from the Meteorological Institute. 6.0, Press News Instrumental Items. 11.30 a.m., Time Signal and Evening Concert, conducted by Karl Weyler: Entr'acte and Announcements. 8.15, Correct Time. 8.30 Concert of Quartet 'Music. 12.30 to 8.0, No Trans- ;nd Ballet Music from " Rosamunde" (Schubert). (approx.), Talk. 7.0, Town Hall Chimes from Copan- mission. 8.0, Opening Signal. 3.5, Concert by the 8.45, Sports Notes. 7.0, Concert or Opera, followed bane. 7.5, " Dyveke," Melodrama in Three Acts, by Wireless Quintet. 4.15, Concert by the Tzigane Orches- by Late News and Announcements, Sports Notes and Hans Werner, Music by Ludolf Nielsen, followed by tra, relayed from the Fiaschetteria Toscana. 5.0 to Programme of Light and Dance Music. ILO (approx.), News and Announcements. 10.0, Dance Music 6.55, No Transmission. 6.55, Opening Signal and Close Down. Programmes by the Palace Hotel Orchestra, conducted News and Announcements. 7.80, Time Signal. 7.35, A 33

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A 34

www.americanradiohistory.com DECEMBER 5th, 1628. Wfipghoo 765 WopIlcl

Cii TOPICJ' Events of the Week in Brief Review.

BEAM TELEPHONE TO CANADA. China, North -West Frontier of India, PCJ CALLING. The Marconi Company is understood to Mauritius and Sumatra. PCJJ, the famous Philips short -wave be contemplating the establishment of a The experiments are to be continued station at Hilversum, is to change its call commercial beam telephone service be- from the same station, which will be con- sign as from January 1st next to PCJ. tween Great Britain and Canada. nected to a small studio in the Palais des This is in accordance with the Washing- 0000 Nations at Geneva. Special efforts are ton agreement. PICTURE RECEPTION AT SEA. being made to reach North and South 0000 America, Japan and Australasia. The " Fultograph " pictures trans- 0000 MORE POWER BY DAY. mitted from Daventry on Monday, Tues- The U.S. Federal Radio Commission, day and Wednesday of last week were HOW TOWNS AFFECT WIRELESS in response to requests by broadcasting picked up with success in the Aquitania WAVES. stations which complained of limited day between Southampton and Cherbourg, and A paper entitled " Alternation of range under the new regime, has granted after the vessel had left the latter port Wireless Waves over Towns," by Messrs. permission for the use of three times the for New York. The pictures showed little R. H. Barfield, M.Sc. (Eng.), and G. H. night power for use during the daytime trace of Morse disturbance. Munro, will be read and discussed at the until sundown. 0000 meeting this evening (Wednesday) of the 0000 Wireless Section cf the Institution of FIRE ENGINE WIRELESS. AMATEUR CUP AWARDS. To Rochdale falls being Electrical Engineers. The paper will the honour of deal Mr. T. P. Allen, M.Sc., has been the first town in Britain to include wire- with the effect of towns, including buildings, tuned aerials, etc., on wave awarded the " Rotab " Cup for 1929 by less transmitters and receivers as perma- damping. the Incorporated Radio Society of Great nent equipment on fire engines. Exhaus- 0000 Britain, being selected as the person who tive tests have been carried out on bad has most assisted private experimenters roads; and, according to reports, the ap- LOUD SPEAKERS, PUBLIC AND during PRIVATE. the past year. Mr. Allen's ener- paratus has successfully withstood the gies have been directed towards maintain- worst shocks. The fire brigade intends to The problem of the outdoor loud ing " contact " between the hundreds of employ wireless to enable fire engines to speaker has again come up for considera- transmitting amateurs scattered up and keep in constant touch with headquarters. tion, this time by the General Purposes down the country. 0000 Committee of the Westniinster City Coun- Another interesting award by the WIRELESS CONTROL CLAIM. cil. The Committee recommends the Society is that of the " Wortley -Talbot " A system of wireless control of gunfire Council to make a by -law prohibiting the Cup, also for 1929, to Mr. J. W. Mathews, in the Navy came up for discussion before use of a wireless loud speaker or a gramo- 6LL, for distinguished work in the 10- the Royal Commission of Awards to In- phone so as to cause annoyance in any metre band. It will be remembered that ventors last week, when Commander C. H. public place, shop or business premises, Mr. Mathews was the first British ama- Rolleston, R.N., claimed an award in under a penalty not exceeding £5. teur to establish communication with the respect of a report submitted to the Ad- The Home Secretary has stated that United States on this wavelength. The miralty. Mr. Swan, counsel for the nuisances arising from the use of such " Wortley- Talbot " Cup is to be awarded instruments in Crown, submitted that H.M.S. Vernon private houses are not, in annually to the amateur who does the best was engaged in wireless control of fire his opinion, of the sort which could be work on the short wavebands. some made the subject of a by -law. 0000 time before the receipt of Comman- 0000 der Rolleston's report. The claim was A BOOK FOR PHOTOGRAPHERS. heard in camera. SAFEGUARDING AERIALS IN GALES. 0000 The publication of " Photograms of the The special safety devices included in Year " is an annual event of great im- LEAGUE OF NATIONS WIRELESS the aerials of the Marconi beam stations portance to all interested in camera work. TESTS. successfully stood the test of the recent The thirty- fourth of the series, just issued The League of Nations has now col- gales. Where interruption in the wire- by our publishers, contains nearly one lected reports from all over the world on less services took place it was due to in- hundred reproductions of fine camera pic- the reception of the short -wave tests re- terruptions in land -lines owing to damage tures, together with critical notes, and its cently carried out from Kootwijk (Hol- in the storm and not to damage in the - contributors include leading photo- land) on a wavelength of 18.4 metres. wireless stations themselves. The aerial graphers in many parts of the world. The total number of reports was 92, clas- wires at the beam stations, which are nor- The book is edited by F. J. Mortimer, sified by the Secretariat as follows : in 38 mally tightly strained, are so arranged F.R.P.S., Editor of our sister journal, cases reception was excellent, in 29 cases that when the wind reaches hurricane " The Amateur Photographer and Cine- it was good; it was fair in 18 cases, the force and undue strain is placed on the matographer." remaining seven being regarded as bad. masts the tension of the wires is auto- It is published at 5s. net in stiff paper The best reports were received from Indo- matically reduced at the lower end. covers, or 7s. 6d. net in cloth boards, ob- A 37

www.americanradiohistory.com . h' , . ;;;*;., ':- WilpshEg DECEMBER 5th, 1928. 766 . W®plld taillable from all booksellers, etc.; Broadcast receivers are a feature of all cation to radio technique," Dr. Walter throughout the country, or direct from five ships of the new Canada -West Indies G. Cady, of the physics department of has been awarded the publishers, Iliffe & Sons Ltd., Dorset fleet. The sets are of sufficient strength Wesleyan University, House, Tudor Street, London, E.C.4. to pick up most of the important stations the 1928 Morris Liebmann Memorial 0 0 0 0 in Eastern Canada, and the United States Prize Medal by the American Institute of BROADCAST EQUIPMENT ON NEW on the regular West Indies run. Ar- Radio Engineers. SHIP. rangements are being made so that pas- The award is made annually to the The Lady Rodney, the new Canadian sengers will be able to listen -in to the member of the Institute who in the National West Indies steamer, which was latest Stock quotations. opini?n of the board of directors lias christened at Birkenhead on Friday last ocoo made the most important contribution to by Mrs. J. H. Thomas, is fitted with a AMERICAN RADIO PRIZE. radio art. Dr. Cady is the author of six -valve wireless broadcast receiving set For " his fundamental investigation in . several important papers on the subject For the entertainment of passengers. piezo- electric phenomena and their appli- of piezo -electricity.

section entertained the Finnish experi- menter, Mr. Bjorklund (ES 2HB), who is TRANSMITTERS' NOTES in charge of the short -wave station OJBT CLUB NEWS. on board s.s. Thorburg during her The station is working European cruise. The Social Side. Short-wave Tests in Manchester. on the 40 -metre waveband, and at the At an enjoyable social and dance evening of The Radio Experimental Society of time of writing the steamer was bound the Golders Green and Hendon Radio Society being to held recently, Col. Vigers, O.B.E., of the 47th Manchester is now licensed under the new for Finland, her next trip Divisional Signals, made a short speech re- regulations for transmission on all bands Cardiff, where she expects to arrive early garding the work of the Signal Division. A - from approximately. 170 metres to approxi- in December. Mr. Bjorklund is very film was also shown by Messrs. Kodak. Ltd.. with depicting some piquant incidents at, the mately 5 metres, excluding the R.S.G.B. desirous of getting into touch Society's last Direction Finding Field Day, held band. The first tests will shortly take British amateurs, and hopes to meet in the neighbourhood of Rickmansworth. place ou 41.5 metres with crystal control several of those in the West Country with Hon. Secretary : Lt. -Col. 11. A. Scarlett, G0, lull, N.W.2. accurate to 0,1 per cent. The Society's whom he has been in wireless communi- D.S.O., Pattison 000uRoad, Childs call -sign is 2E2. cation. The Value of Joint Meetings. All radio amateurs in the Manchester At a joint meeting of the Croydon and in Thornton Heath Radio Societies at South Croy- district who are interested short -wave FORTHCOMING EVENTS. don on Tuesday, Nov. 20th, Mr. H. R. Rivers, work are invited to communicate with the Moore. B.Sc., President of the South Croydon WEDNESDAY, DECEMBER 5th. The Hon. Secretary, Mr. R. M. Kay, Institution of Electrical Engineers, Wire- Society, lectured on and demonstrated " Grid Valve Set." Capt. Derek B.Sc. 2, Daisy Bank Road, Vic- less Section. At 6 p.m. (light refresh- Latest Screened (Tech.), ments at 5.30). At the Institution, McCulloch (of the B.B.C.) occupied the chair. toria Park, Manchester. Savoy Place, IV.C.2. Paper on " Atten- After explaining the internal features of the 0000 uation of Wireless Waves Over Towns," valve and the importance of the external by Messrs. It. H. Barfield, M.Sc. (Eng.), screening, the lecturer demonstrated his set, Among the Belgian Amateurs. and G. H. Munro. which included two screened grid stages. Ample Mr. Louis Era, the district manager for North Middlesex Radio Society. At 8 p.m. volume was obtained with many distant At St. Paul's Institute, Winchmore Hill. stations. and the purity of reproduction was Antwerp of the Réseau Belge, tells Lecture: "Transformer Amplification," fully appreciated by the large and critical by Mr. Garside, of Messrs. Ferranti, Ltd. us that the Belgian Training Ship At audience. Edinburgh and District Radio Society. At the conclusion of the meeting. the Hon. L'Avenir sailed on November 3rd for 8 p.m. At 117, George Street. Business Thornton Heath Society Fort de France, Martinique, and Tampa, fleeting. Secretary of the Muswell Hill and District Radio Society. stressed the value of holding joint meetings, Florida, equipped with a short -wave At 8 p.m. At Tollington School, Tether- and said on behalf of 'his Society that he poped transmitter and using the call -sign XEB down. Radio Gramophone Night. to reciprocate the invitation in- the near future. Tottenham Wireless Society. At 8 p.m. }ton. Secretary (South Croydon Society), Mr. 4WK. The wavelength is 32.50 metres, At 10, Bruce Grove, N.19. Business F.. L. Cumbers, 14, Campden Road, South the input being derived from accumu- meeting, followed by sale and exchange. Croydon. lators. Three TB04/10 valves THURSDAY, DECEMBER 6th. 0000 Philips' Ilford and District Radio Society. Lecture: Wireless and Gramophone Reproduction. are employed, one as a master oscillator " The Screened Grid Valves," by the A demonstration in which radio reception controlling the other two ,and working ou .Marcosiphone Co., Ltd. (with lantern and electrical gramophone reproduction were illustrations). compared was the feature of the meeting of an input of about 20 watts. Slade Radio (Birmingham). Lecture: (Birmingham) on Nov. 22nd, This interesting short -wave station is " Loud Speaker Design and Construc- Slade Radio tion,' by a repreaentativt of Mesura. S. G. the demonstrator being Mr. Reuben Heaton. in the charge of Mr. G. Regnier (4WW ) Brouet, Ltd. Wireless was represented by an " Everyman and Mr. G. Neelemans (4FT), who at first MONDAY, DECEMBER 10th. Four " receiver and a Wireless World mov- Netceastle- upon -Tyne Radio Society. At ing coil loud speaker. The gramophone was a experienced considerable difficulty owing 7.30 p.m. At 11, Saville Row. Lecture: Panotrope. The lecturer favoured push -pull in to the steel wire rigging of the three - " A.C. and D.C. Battery Eliminators,' by amplification with a low amplification valve vessel which caused an un- Mr. C. L. Lyons, M.I.R.E. the first L.F. stage and a tapped anode resis- masted sailing Hackney Radio and Physical' Society. At tance as volume control. Some interesting con- steadiness of the note. However, by 8 p.m. At Hackney Electricity Show- trasts were provided when broadcast reception using a master oscillator with power rooms, Lower . Clayton Road, E.S. Dis- was followed by a number of records giving it cussion on " New Valves and their A keen discussion amplifier the signals improved greatly with Pentode demonstration. wide range of instruments. Merits," followed tite demonstration. both in quality and steadiness. lion. Secretary : Mr. H. Clews, 52, St. XEB 4WK is working regularly at EB 4BC to be Crystal-Controlled. Thomas Road. Erdington, Birmninghtmi. during the present 0000 2300 G.M.T. Since his return to Antwerp Mr. Era The Rich Man's Set. month. Messrs. Regnier and Neelemans reconstructing his station A receiving set built regardless of cost with has been busy obtaining adequate volume are anxious to get into two -way communi- EB 4BC, which is now transmitting on the sole object of and reports with absolute purity of reproduction was demon- cation with British amateurs, 42.50 metres with a master oscillator and strated by a representative of Messrs. Bridge of signals heard may be sent to them via power amplifier, av,d will very soon be and Sons at a recent meeting of the Southend Réseau Belge, 11, Rue du Congrès. and District Radio Society. Impressive results crystal -controlled. He is using a i -wave were obtained and some interesting comparisons Brussels. 0000 Hertz aerial, and even without the crystal were made on several types of loud speaker. has been reported as " T9 " from Hon. Secretary: Mr. b'. J. Waller, Lynthorpe, his note Southend -on -Sea. Antwerp Welcomes Visitors. Spain, Russia, Sweden, England, and Grange Gardens, 0000

Any British amateur visiting Antwerp Ireland. Prizes for Talks. - welcomed by the local 0000 The hitherto silent members of the Edinburgh will be cordially and District Radio Society are to have a con- members of the Réseau Belge. During A Bolivian Station. crete inducement' to share in the discussions. the summer Mr. R. L. Varney (2ARV) Mr. Mark Johnson (SO 1AA). Tipuani, The meeting this evening (Wednesday) will he in is transmitting on 33 metres and devoted to " Lecturettes," a new monthly attended one of the " reunions" held Bolivia, feature in connection with which a prize of one the " Paon Royal ' on Tuesdays at 8.30 wishes to get into communication with guinea will be awarded for the best paper read p.m., and on November 6th the local British stations. during the quarter. A 38

www.americanradiohistory.com w' ...... '. r. - : - ._ 1928. WflMil@00 DECEMBER 5th, 767 WnrPi1 r,l

Cossor Screened= Grid Valve S.G.220.

Y this time readers must be there will be a slight voltage drop in familiar with the unique pro- the wiring probably of about the 13 perties of the screened -grid same order. valve. By fitting a fairly close - The potential on the screened - meshed grid between the anode and grid was kept at 6o volts and a num- the control grid of a valve, its A.C. ber of measurements taken with o, resistance is greatly increased, but as 0.5, -- 1.0 and 1.5 volts applied this is accompanied by a propor- The Cossor screened -grid valve S.G.220 for use with a 2 -volt accumulator. to the control grid. It will be seen tional increase i_ the amplification that the curves are of rather pecu- factor the efficiency of the device is ment current during the test, an liar shape, the anode current rising of the same order as that of the aver- ammeter with a very low D.C. re- rapidly with low anode potentials age triode. Unfortunately, there is a sistance was included in the filament followed by a sharp decline as the limit to the amplification that can be circuit, but with the exception of this voltage is increased and between 40 obtained from a single stage and no other resistance was used. and 55 volts actually a reversal in this is reached when the feed -back The measured voltage across the direction of flow takes place. This via the valve causes self- oscillation. valve pins was a fraction under two is due to the secondary emission In the Cossor screened -grid valves and the filament current 0.19 am- from the plate and must be left at the anode is connected to a small pere. This compares favourably that as the cause and effect is too bakelite shrouded terminal on the with normal working conditions, as involved for treatment here. top of the glass bulb, and the other electrodes are connected to a stand- Mutual Conductance of One. ard 4 -pin type of base. The control COSSOR S.G.220 The part of the- curve with which grid and filament pins have the we are concerned when using the

I I ! I 52 I I same relative position as on an or- SCREEN POTENTIAL 60V. valve as an H.F. amplifier is the dinary 3- electrode valve, but the pin FILAMENT 0 2 AMP AT 2 V. slightly rising portion between 90 4 8, usually connected to the anode is in and 150 volts, and it will be seen this case the termination of the 4 4 G.B. 0 that between these limits the curves Ill screened -grid. One advantage of . are sensibly parallel although at this arrangement is that the ordinary 401 mil 1111_ zero grid volts the curve shows a 3 11 valve holder can be employed, but 6 G -05 tendency to rise more steeply. The the main reason for this method of a v A.C. resistance of the valve will vary 41 ONE construction is to keep the inter - 3 2 G B.-1.0 with different grid potentials and electrode capacity reasonably small 2 1 anode volts, but if we take approxi- 2 111 without leading to an excessive diffi- 611/T mate working conditions, namely, culty in manufacture. w 2 4 13o volt H.T., i.o volt G.B. and cc cc III/%1I s II/ 6o volts screen potential, the A.C. Secondary Emission Effects. Ú20 resistance will be 188,000 ohms, and The introduction of the screen so II the amplification factor 188, giving alters the characteristics of the valve Ó 1 6 a mutual conductance of one. This that it is customary to show these á12 !)11 I compares favourably with the of in the form the relationship be- 0'8 makers' figures- 2oo,000 and 200 tween anode voltage and anode cur- , respectively -and moreover is of the rent with various grid potentials and a4, \ same order, so that it is reasonable a fixed screen voltage rather than as \ to conclude that the specimen tested grid voltage -anode current curves. o 20 40 60 80 100 120 140 is a representative sample. The specimen tested was the 2 -volt ANODE VOLTS The most suitable voltage values type- S.G.220-which is rated to for normal operating conditions Characteristic curves of the Cossor S.G.220 pass 0.2 ampere through the fila- valve. Average values, A.C. resistance would appear to be between iio and ment at this pressure. For the pur- 188,000 ohms, amplification factor 188, 150 on the anode, and 6o on the mutual conductance 1.0 mA'volt with pose of keeping a check on the fila- 130 volts on the apode, and - 1.0 volt G.B. screen. A 39

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Accumulators, D.C. Mains, and a Charge = Discharge Switch.

tain the simplicity of a double -pole switch. As pointed out on previous occasions, this arrangement has the HATEVER may be the position with regard to advantage that all cells of the battery are equally dis- those having access to A.C. mains, there can charged ; this is apart from the fact that the series re- be little doubt that amateurs with D.C. supplies sistances, in conjunction with their by -pass condensers, are chary of using eliminators. In view of the pitfalls serve to isolate the various signal- frequency circuits, and so often encountered when applying this form of supply to prevent any undesirable interaction. direct to the receiver, their attitude is reasonable ; mat- Even if the set requires a number of different H.T. ters are complicated by the fact that some systems have voltages, no very serious complication will ensue, but a positive earth -which means that the majority of the it will be necessary, as shown in diagram (b), to fit a receiver wiring will be above earth potential -and also switch having a greater number of poles -one for the because one can seldom predict how much smoothing negative connection and one for each of the positive will be necessary in order to correct ripples and irregu- tappings. larities, which are of widely varying intensity. As D.C. Charging Rates. current will no longer be supplied for domestic purposes in this country after a few years, one naturally hesitates The diagrams are almost self -explanatory ; to operate to face a heavy expenditure for an elaborate eliminator the set the switch blades are moved to the left, while or the parts to make one, and the possibilities of using to recharge the battery they are placed in the reverse H.T. accumulators become attractive. position, so that current from the mains is passed through the battery. In each of the diagrams a resistor R and a Voltage Dropping Resistances. lamp are shown ; it is not necessary that both of these If D.C. mains of a sufficiently high voltage are avail- should be used, as long as there. is sufficient resistance able, the cells can be charged at negligible cost, and in circuit to restrict the flow of current to a value not provided that a switch is installed in such a way that exceeding the maximum charging rate specified by the the operation of charging may be carried out without manufacturers. trouble, there is no excuse for neglecting the battery, The calculation of this resistance is quite a simple and its life will be a long one. matter : the first operation is to find the voltage avail-

How an H.T. battery may conveniently be recharged from a D.C. main supply: alternative connections for a charge- discharge switch.

It is to sets in which a common H.T. voltage is able for charging purposes. This is ascertained by sub- applied to all the valves that this kind of switching can tracting the rated voltage of the battery from that of the be most easily applied ; the connections are as shown mains. We can now work out the resistance necessary in the accompanying diagram (a), but it may be pointed by dividing this voltage by the required charging cur- out that it is always possible to insert series resistances rent- (in amps.). As an example, let us assume that it in the anode circuit of those valves which require less is desired to charge a i2o -volt battery from 240 -volt than the maximum pressure available, and thus to re- mains at zoo milliamps (o.i amp.) : in this case the A 40

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1928. Wp@R@MO DECEMBER 5th, 769 WUWIle A Safe H.T. Supply. - and to avoid passing an excessive current, a lamp with voltage available for charging, after subtracting the the next lowest wattage rating to that which would back -pressure of the battery, will amount to 120 volts, apparently be necessary should be chosen. and we can get the necessary value of resistance by If a wire-wound resistor is preferred, its value is, of dividing 120 by o.1, the result being 1,20o ohms. course, chosen in exactly the same way, but as a re- As already suggested, the exact form taken by the minder that the cells are on charge, it is desirable to limiting resistance is unimportant-provided it will safely insert a milliammeter (in the position shown in diagram pass the desired current -and an ordinary electric lamp (b)) or a small flashlamp bulb, which will also be in is certainly the least expensive and simplest. Its re- series with the charging circuit, as indicated in both sistance may be ascertained by dividing its rated wattage diagrams. The resistance of this lamp will be relatively by rated voltage ; this gives the current passed (in so small that it need not be taken into account. amps.). This may be converted to resistance (in In cases where the wireless receiving apparatus is in ohms) by dividing the figure thus obtained into rated use every day for a number of hours, it will often be voltage. Unfortunately, however, the resistance thus found convenient to make it a matter of routine to place ascertained will only be effective when the lamp is the battery on charge when the set is switched off ; in glowing at full brilliancy, and not when the voltage these cases the charging rate should be fixed at some- applied to it is opposed by that of the battery that is thing considerably less than the maximum specified being charged. As is well known, the resistance of a rate, but sufficiently great to make good the drain on lamp decreases as the voltage applied to it is reduced, the battery during its working periods. H. F. S.

USEFULSEIFT1,_ w DATA CHARTS. (N050 `:E3 N AA.)AO) Self= Inductance of Multilayer Coils. r1HE self- inductance of a multilayer coil of circular square section, whose mean turn has a diameter of Sins. section is given by the formula :- (as measured by calipering across opposite vertices of L = LQ,.N2.D. the square and subtracting the diameter of the wire), is where L is in microhenrys. equivalent to a round -section coil of mean diameter N = total turns. 2.43ins. D = mean diameter of coil in inches.' Lo is a factor depending both on the ratio of axial r-3.4347 length to mean diameter and the ratio of radial thick- ness to mean diameter. 00000 3.434e The abac is constructed in exactly the same way as m 00000 No. 17, but several curves are each 00000 drawn, one for value i7 00000 of t/D (ratio of thickness to mean diameter). An inset 00000 is provided to show the method of procedure, and a sectional drawing of a coil makes clear the meaning of the quantities 1, t and D. 00000 An Example. 00000 A coil of circular section has 316 turns ; its external 00000 diameter is 4.331ins., while its internal diameter is 00000 Q 3.543ins. ; its thickness is 0.394in., and its length 0 0 0 0 3.937ins. Accordingly // D = r ; t/ D= o.1; N=316 ; D = 3.937ins. ; and from the abac we should find L= Fig. 1. -An example of a square -section coil with side measuring bins. Assuming 200 turns, and by using the abac given this week, 6,196 microhenrys, this being the calculated value. the inductance works out at 4,425 microhenrys. Multilayer Coils of Polygonal Section. Strictly speaking, the correction factor should vary A multilayer coil built up on a former of polygonal with the ratio of length to mean diameter, but between section has the same inductance as one of circular sec- the limits 2 and o.1 of this ratio the variation is less tion possessing the same length, thickness,' and turns than the probable error in working abac 18. provided that the mean diameter of the circular section coil bears a certain relation to that of the coil of poly- An Example using a Square- section Coil. gonal section. This equivalent diameter is given by As shown in the figure the mean turn forms a .square abac 18a, which is self=explanatory. Thus a coil of whose side measures 6ins. ; the diameter of its circum- circle is ' Mean diameter = overall diameter of mean turn, less dia- 8.486ins. Abac 18a gives the equivalent mean meter of wire. Length = number of turns in one layer multiplied diameter as 6.87ins. Accordingly, the equivalent coil has by axial pitch. Thickness= number of layers multiplied by 1/D 3 434 3.434 radial pitch. - 0.5, and //D = 0.5. Hence, 6.87 6.87 2 By thickness is meant the radial thickness measured along a radius drawn at right angles to the direction of the wire and assuming zoo turns, abac 18 gives L = 4,425 micro - not a radius drawn to a vertex of the polygon. henrys. A 41

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20,000 } 100 60 80 70 60 15,000 80 50 40 90 025 -10n 30 10,000 9,000 20 8.000 150 7.000

6.000 200 05 5,000 04 4,000 4 300 VALUES OF t/D 03 3.000 400 2-

500 02 2.000 600 0'8 700 1 06 0.15 1,500 800 O o 0 0 0.5 0 O O Ó 900 O O O O-- LENGTH /DI 04 O O 0 O 1.000 O o 0 O 0.3 01 1,000 0 09 900 02 0 08 800 0 15 - 1,500 O O O O 00 o o 0 0 ó O---' MICE ó_ O o 0 0 O o O

SELF INDUCTANCE OF MULTILAYER COILS OF CIRCULAR SECTION FOR CORRECTION FACTOR REQUIRED FOR COILS OF POLYGONAL SECTION SEE ABAC NO 18 a.

W V. ABAO N° 18

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By Our Special Correspondent. Christmas Broadcasting Arrangements. -Studio Design at " Broadcasting House. " -An Imaginative Forecast. -British Stat4ons Heterodyned.- Largest Cathedral Organ Broadcast.

Christmas Broadcasting Novel Pantomime Idea. The Studios in " Broadcasting House." One of the first " Christntassy " Ernest Longstaffe, who is busy on the 'l'he recent official announcement con- broadcasts has been arranged for Mon- script for a pantomime " Dick Whitting- cerning the design of the new Broad- day, December 17th, when listeners to ton," to be broadcast on Boxing Day, tells casting House in Portland Place con- t 2L0, 5XX, and several other stations me that he has " adhered to the story firms much that has already appeared will hear Community Carol Singing by absolutely." in these columns. the boys of Canford School, Wimborne, This is something new in a pantomime! All listeners will be glad to note that Dorset. On the same day there will From what I can remember of pantomimic the primary consideration will be the be a carillon broadcast front Messrs. entertainment, the story is lucky if. it design of the studios. To the man at Atkinson's, Old Bond Street, the re- gets a look iii. The time is usually the receiving end it would be small satis- citalist being the noted Belgian caril- monopolised by the principal " boy," the faction, if reception were poor, to know lotteur, Chevalier Jef I)enyn. mot w, and the knockabout that the music was coming front the 0000 comedians. most magnificent building in London. He would be in much the same case as " The Messiah." the Irish tourist in the Tube who had A cathedral rendering of " The to get what comfort he could from the Messiah " is such a rarity nowadays announcement that he was passing that special interest attaches to the under some of the most interesting broadcast on Sunday, December 23rd. parts of the Metropolis. This will consist of the full choral and 0000 orchestral version of Handel's best - Studying Acoustics. krown oratorio from York Minster, be- Of the nine studios, four will be more ginning at 2.30 p.m. It will be relayed than double the size of the largest to 2L0 and 5XX and to a number of studio at Savoy Hill, which is 44ft. by other stations. 25ft. In addition to these, there will 0000 be a super- studio, three storeys high, of Wassail. approximately 4,000 square feet, which, The Yuletide spirit will find au outlet together with its gallery, will be capable on Christmas Eve in " Wassail ì la of accommodating an audience of 1,000, Carte," a musical programme to be as well as a large orchestra. oponed with a Frankan- British overture. It is chiefly in connection with the Mr. Gilbert Frankan will be present to construction of this studio that Capt. contribute an item of his own, and will West and his assistants are busy de- be supported by the Gershotn Parking - veloping the acoustic measurement ap- ton Quintette with Yvette Darnac and paratus to which I was able to give Ilex Palmer. exclusive mention last week. Later in the evening listeners will 0 o n 0 hear carols front the churchyard of St. Brick Walls as Sound Insulators. Mary's, Whitechapel. It is noteworthy that the studios in 0000 Portland Place will be the first in this On Christmas Day country to be built as studios ; up till "BROADCASTING HOUSE." The now every studio has been an adapta- There will be no dearth of broadcast approved design for the B.B.C.'s new fare on Christmas Day. Lunch hour building at Portland Place, London, W. tion of an existing room, and it speaks music from the Hotel Cecil will be fol- The studios will be situated in the central much for the resourcefulness of those block, the surrounding offices giving pro- concerned. that there are so few really lowed by a special Christmas concert tection from street noises. in the afternoon, provided by the \Vire- bad studios in existence at the present its part, too, lèsss Military Orchestra, with Catherine Alice at the Microphone. time. Luck has played Stewart (contralto) and William Prim- An adaptation of Lewis Carroll's for it was not until outside broadcasts were tried that the engineers discovered rose (violin). fantasy, " Alice Through the Looking - Laurence Housman's nativity play, Glass," which, prepared by Mr. Cecil how fortunate the authorities had been Bethlehem," will be broadcast from Lewis, is to be given from 5GB on Decem- in the choice of the Savoy Hill build- 2L0, 5XX, and other stations at ber 18th, and from 2L0, 5XX, and other ing, which contains no steelwork and 4.45 p.m. The Children's Hour will be stations on December 21st. I hear that enjoys the sound insulating properties given as usual. the B.B.C. is wondering whether the part of brick walls. 0000 The most seasonable item in the 2L0's of the Leg of Mutton should be played by evening programme will be a reading a man or a woman. This just shows what Auxiliary Suites. by lam, Hay from " The Holly Tree," problems the Corporation is called upon In the now building the studios will by Charles Dickens. to face. he insulated from the outer world by 44

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DECEMBER 5th, 1928. WIp®hop Wade), 773 wide corridors and thick brick walls, Organ Recital from Liverpool while a surrounding layer of offices will FUTURE FEATURES. Cathedral. afford additional, protection from street London and Daventry. A recital by .Mr. H. Goss Custard noises. DECEMBER 10TH. -The Ceremony of the on the Liverpool Cathedral organ -the Keys, relayed from the Tower of To each of the four large studios will London. largest cathedral organ in the world- - be attached a suite comprising waiting DECEMBER 12TH. -" Life's Dream," t y will be relayed to 2L0 and 5XX on room, listening room, echo room, Calderon. Friday next, December 7th. The organ and DECEMBER 14TH.-Symphony Concert, te rooms for the band, announcers, and layed from the Queen's Hall. has five manuals and 168 speaking stops. engineers. Daventry Exp. (5GB). 0000 DECEMBER 9TH. -String Orchestral Con- 0000 cert. Enter : A Brass Septet. An Important Item. DECEMBER 12TH. -" The Heart of a -1 Hew instrumental combination is to Clown," by Constance Powell-Ander- I am told that another important son. fan-e the Belfast microphone for the first apartment will not be forgotten, viz., DECEMBER 13TH. -Hallt Concert, relay, d tinte on December 11th. This is the the canteen. Needless to say, the avail- from the Free Trade Hall, Dhu,- Station Brass Septet, composed of the chester. brass players from the Station Orchestra, able refreshment will be perfectly in- DECEMBER 14TH. -" The Stepmother," a nocuous, as the B.B.C. licence is merely farce by Arnold Bennett. which will play specially arranged selec- a wireless one. Cardiff. tions. They are supported by that popu- DEcmtsej 9TH. -The first eencert of the 0000 Cardiff Musical Society, 1928-U lar duo, Grace Ivell and Vivian Worth. 0 0 3 0 The Financial season. Side. Manchester. Mr Percy Scholes. The building is to cost DECEMBER 12TH. -How to Dance, a pro- between gramme of Although £400,000 and £500;000, the money old -fashioned dances. Mr. Percy Scholes relin- being DECEMBER 13TH. -Hallé Concert from quished his position as music furnished by a syndicate from whom Free Trade Hall. critic of the the B.B.C. to go and live and work in Corporation will lease the premises with Newcastle. an option to DECEMBER 9TH.-" The Last Judgment " Switzerland, he has not severed his con- purchase if and when this (Spfihr), Part 1, relayed from Dur- nection appears desirable. ham Cathedral. entirely with the microphone. Doon Glasgow. On December 15th he is coming to Eng- DECEMBER 10TH.- Voire, Violin and Flute land to broadcast another of his popular An Imaginative Forecast. Recital. " in Music DECEMBER 13TH.-A Pantaradioptimime. New Friends " recitals from There are more than the immediate Aberdeen. 5GB. The illustrations on this occasion financial considerations to account for DECEMBER 14TH.-.--" The Storm," a short will be from Gustav Holst's " The this cautious attitude of story by H. Mortimer Batten. Planets." the B.B.C. An Belfast. 0000 official explained to me that the Cor- DECEMBER 11T11.- Progranuue of Gipsy poration was looking ten, twenty, and Music. A Wagner Night. even thirty years ahead. There is no Tite Festival Theatre at Bayreuth, the knowing how broadcasting may develop kind outside London. 'l'he B.B.C. last home of Wagner's music, has as its pre- in the next quarter of a century; it is year broadcast a running commentary on sent conductor Franz von Hoesslin. He conceivable that present -day conditions the spectacle along with dance music. is coming to London on December 14th may have been entirely superseded. This proved to be so much appreciated to conduct the fifth of the B.B.C. sym- The Corporation turns its imaginative that this year they have arranged a more phony concerts at the Queen's Hall. eye on a time when studios may be dis- elaborate commentary which will be As plight be expected, the programme pensed with ; when television makes it relayed to all Scottish stations on Decem- will consist to a large extent of Wag- possible for the individual members of ber 21st, and will consist of short nerian music -the Siegfried Idyll, the an orchestra to perform in their own snatches of commentary interspersed with Good Friday Music, and trie overtures to homes. . ! dance music. " Tannha user" and " The 11 n.rsingers.' Yes, the B.B.C. has imagination. oOna A Useful Accessory. Extract from a letter which blew into Savoy Hill last week : " My coil has ten tappings at one end and a barometer at the other." Evidently he hadn't thought of tapping the barometer. 0000 Wavelength Muddle Grows. More and more of the B.B.C. stations are being heterodyned by Continental transmitters. The sooner the wavemeters necessary for the common wavelength scheme are delivered the sooner will listeners to the relay stations be assured of uninterrupted reception According to Savoy Hill, every one of the relay stations is now being heterodyned, the worst case being that of Bournemouth, which is jostled nightly by three offenders not yet identified. Listeners situated more than 150 miles from 5XX are finding that the transmis- sions are upset both by Königswuster- hausen and Lahti (Finland). 0000 An Edinburgh " Revel." The students of the Edinburgh College of Art claim that their annual "Revel " WIRELESS WHILE YOU WAIT. A scene at a station on the Hungarian State Railways. which provide intending travellers with broadcast entertainment while waiting for provides the most striking spectacle of its trains. Note the radio attendant on the left. A 45

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7¡.7 WAp@R®g0 DECEMBER 5th, 1928. MUpild.

- _ - 4 z < á.- WIRELESS WORLD

A Review of Manufacturers' Recent Products.

A.B PRODUCTS H.F. CHOKE. indicates that the number of turns used POSTLETHWAITE COILS is above the average. 'l'he windings are These coils are wound on ribbed The inductance of this choke is con- taper former, siderable, and resonance is not reached carried on a double -ended formers, and each consist of an aerial and, as the distance between the two even at a wavelength of 3,300 metres. coil, grid coil, and reaction winding. cones is greater than the distance between The coils for the medium wave band are the sub- sections of the winding, the layer wound with turns touching, and as choke is divided into two closed circuits the winding length to diameter ratio is and behaves as two chokes in series. This considerably less than unity, they should causes the kink in the impedance curve be quite efficient coils. at 1,200 metres which may cause trouble The short wave coil, which covers a through self -oscillation between 1,100 and wave band of from 18 to 40 metres, is 1,200 metres in a receiver designed to wound with spaced turns, enamel covered cover the 1,000 -2,000 metre waveband. Between 200 and 500 metres and at 1,600 metres the performance will be perfectly satisfactory, and the impedance values at these wavelengths will be as follows :- Wavelength (metres). Impedance (ohms). 200 11,000 500 41,000 1,600 192,000 The choke is mounted on a vertical may be swivelled for wiring A.B. Products H.F. choke; D.C. resist- bracket and ance 1,420 ohms. in a horizontal or vertical position. The makers are Messrs. Accessories Enamelled wire of fine gauge is used and (Birmingham), 40, Weaman Street, Bir- the high D.C. resistance of 1,420 ohms mingham.

300.000 A range of six pin aerial -grid coils. Note the special long wave coil in the foreground.

2 wire of generous cross -sectional diameter z g 200.000 being employed for the grid coil, and a slightly smaller gauge for the reaction winding. In this particular coil the aerial is tapped to a point on the grid coil so that half a turn only is in the aerial circuit. The grid coil has 42 com- plete turns and the reaction six. A long -wave aerial -grid transformer on the same general lines as the medium- wave coil completes the range. In this are 500 1,500 2,000 3,000 3,500 case, however, sectional windings 1Á00 adopted, the two lover grooves carrying WAVELENGTH (METRES) the aerial coil, the next five grooves the grid coil, and the top pair the reaction. Of more interest is a long- In: peclnnge curve of A.B. Products H.F. choke; external capacity 8 micro-mid. particular ' A 46

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DECEMBER 5th, 1928. Wfipa®M. 775 MAOOpIlCo`1 wave aerial -grid coil designed to give provided, however, by means of which this increasing as the frequency is re- improved selectivity on the long waves. the track error can be evenly distributed duced. B- choosing suitable values for Selectivity is governed by the degree of over the range of movement of the arm. the chokes and condenser it can be coupling between the aperiodic aerial coil The price of this component, which is arranged that the network resonates low and the tuned grid coil, but with the made by the Watmel Wireless Co., down on the audio scale, thereby main- optimum number of turns the aerial cir- Ltd., Imperial Works, High Street, taining a high cuit amplification over a large often resonates well below 600 Edgware, is 7s. 6d. portion of the scale. The Igranic dual :m metres, with the result that signals from 0000 pedance coupler consists of two iron -cored a powerful broadcast station of medium A PEDESTAL CABINET FOR THE inductances wound on separate wavelength cores and will force their way through " MEGAVOX THREE." mounted side by side with a condenser even though the grid circuit is tuned to The design of this cabinet is quite built in. The connections between the about 1,000 metres. To overcome this original, and the dimensions are such that chokes and undesirable condenser are made internally state of and four terminals are provided for the affairs, the special long - required outside connections. wave transformer type From a curve which MM3 accompanied the /LS is fitted with a sample sent to us, we notice that when large primary (or aerial) used with valves of suitable impedance coil, but to maintain the an amplification required of 7 is obtained at fre- loose coupling quencies in the region of 40 cycles, a part only of this coil is coupled and this rises to 8 at 60 cycles. to the As the grid winding. The remainder frequency is increased there is a is wound in two grooves slight well spaced falling off in amplification to about 7 from the grid coil, this portion between 100 and 200 cycles, being and from astatically wound. The turns on 300 to 6,000 cycles the amplification is one section are wound in the opposite fairly constant, about direction 7.75, and this is to the turns in the other, followed by a slow decline between 6.000 thereby reducing the external magnetic and 10,000 cycles where the amplification field, and hence the coupling. The drops again to 7. It would appear, designers, Messrs. Postlethwaite Bros., therefore, that, with the particular valves Church Hill, Kinver, Stourbridget are to used, the mean amplification between the be congratulated on the ingenuity dis- two limits given, namely, played 40 to 10,000 in overcoming a rather difficult cycles, is about 7.5. The maximum varia- situation. The price of the special tion over the whole band is a fraction long -wave coil is 10s. 6d., and of over 10 per cent. or barely the ordinary sufficient to type 8s. 6d. each. be detected by the ear. This curve was

WATMEL PICK -UP CARRIER. Although light in weight, the construc- tion of this component is massive. " Aconicab " pedestal cabinet for the Polished aluminium castings are used Megavox Three." The dimensions are throughout, and such that the cabinet serves also as an the adjustable single - occasional table. ball pivot bearings give a practically frictionless movement without side play. it can be used also as a small table for The main arm is allowed lateral move- various purposes. The polished oak top ment only, and in no way adds to the measures 18in.x25in., and the middle pressure of the needle on the record. The section slides out revealing ample space pick -up is clamped in a small aluminium in the interior for batteries as well as rocker arm of negligible weight, so that the receiver. A special three -ply partition the pressure on the needle is little more is supplied to separate the set' from the than that due to the weight of the pick- batteries. up itself. A set -screw is provided for The overall height is 30in., and the controls fall con- veniently to the hand when operating the set from an armchair. The maker is A. V. Clarke, 22, Old Montague Street, London, E.1, and the price The Igranic dual impedance coupling is £3 10s. in pol- unit. ished oak. taken using two stages of dual im- O 0 O O pedance coupling. The DUAL IMPEDANCE makers are the Igranic Electric COUPLING. Co., Ltd., 149, Queen Victoria Street, Dual impedance coupling can be de- London, and the price is 30s. scribed best as a choke- capacity coupling, 0000 but with a low -frequency choke in place of the high resistance between the grid TRADE NOTE. and filament (or grid Watmel pick -up arm with cast aluminium bias) of the follow- The business of Messrs. Frank Kay members and adjustable ball bearing. ing valve. The advantages of this and Co., 40, Clifton Street, Lytham St. method may not at first be apparent, but Annes, has now been taken over by fixing the pick -up, and the diameter of in all systems depending on a condenser Messrs. Wilkinson's Wireless Service the hole is tin. linkage the reactance, or resistance, of Co., 47 -48, Cannon Street, Preston. All Simplicity is the keynote of the design, the capacity plays no mean part in the goods and correspondence should there- and no device is included for correcting amplification obtained. The reactance of fore be forwarded to the Cannon Street for track error. An alignment card is the condenser varies with the frequency, address in future and not to Lytham. A 47

www.americanradiohistory.com T-n Wilp@hoo DECEMBER 5111, r928. WU1rlica

Interesting Improvements and Modification in the New Model.

sHE Graves two -valve set needs no introduction to uniformity both scales are engraved in degrees from o to our readers. In its original form it was reviewed i8o, so that the zero of the right -hand reaction dial is in the issue of July 27th, 1927, and in the new really at 9o° Nvitli maxima for long waves and medium design the basic features which contributed so much to «aver at o° and 180° respectively. When the wave- the success of the first set have been retained. The ra nge switch is at " Long," reaction increases from 9o° to tuner is essentially the same, and consists of two coils, zero, and at " Short " from 9o° to 180°. one for long and one for medium waves, connected in The original wood baseboard has been replaced by a series with a switch for cutting out the long -wave coil special moulding with corner webs which are screwed to when receiving on the medium B.B,C. waveband. A the front panel and make angle brackets superfluous. reaction coil swinging through an angle of 18o degrees The terminal strip is moulded integral with the base- couples with either coil according to the waveband in board and carries the loud speaker terminals as well as use. The coils are wave -wound on ebonite centres, the earth and alternative terminals for the aerial. The shellacked and baked, and the complete unit presents a battery leads are brought out through holes in the ter- particularly neat and compact ap- minal strip and are already fitted pearance. The " Utility con- with spade terminals and wander denser is retained for tuning, but plugs. instead of using a fixed series con- Improved Quality. denser for improving selectivity and, if necessary, reducing wave- Other points of interest in the length, the alternative aerial ter- specification of the receiver are the minal is connected to a tapping redesigned filament and wave - point on the tuning inductance. change switches and the substitu- Otherwise the circuit remains as tion of a P.AI.2 for the original before, and the leaky grid detector P. AI. i valve in the output stage. is followed by a transformer - With the exception of the loud coupled L.F. amplifier feeding speaker the accessories remain direct into the loud speaker. much as before. The new horn - type loud speaker is of massive de- Modified Layout. sign and construction, the goose- "Vulcan" The layout has, however, been Interior of the Graves receiser showing neck being a heavy iron casting. moulded bakelite baseboard and terminal strip. flare is of spun metal, and is slightly modified ; the tuning dial is The now on the left and reaction on the right, all the terminals fixed to the neck by three screws. The joint is well fitted are fitted at the back of the set, and the L.F. transformer and there is no trace of jarring. An adjusting screw for (now a B.T.H.) is situated between the two Aermonic the movement is situated under the base. anti -microphonic valve -holders with the grid bias battery The quality of reproduction has been improved by the immediately behind it. use of the P.111.2 output valve, and is more than sufficient has been greatly enhanced by a for the average living room. The selectivity is much the w- ' The appearance moulded bakelite front panel with large- diameter en- same as in the original design, and is sufficient to separate graved bevel dials set in an oval recess. For the sake of 5GB from 2L0 in London -no mean performance for a A AR

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DECEMBER 5th, r928. WAp4@oo Wald 777 Broadcast Receivers. Graves Vulcan " Two. - complete with aerial equipment and all accessories, two -valve set at only i4 miles from the latter station. remains at 7 17s. 6d., a figure which represents extra- The selectivity is not quite sufficient to enable Continental ordinary value when the quality and performance of the stations to be received in the London area, but during outfit are taken into account. Further, the makers, intervals in the transmission from 2L0 several German Messrs. J. G. Graves, Ltd., Sheffield, are prepared to stations can be heard on the loud speaker. send the set on approval and also on very favourable The price of the new model, including royalty and deferred terms. LETTERS TO [HE EDITOR. The Editor does not hold himself responsible for the opinions of his correspondents.

Correspondence should be addressed to the Editor, ' The Wireless Wond," D'rset House, Tudor Street, E.CA, and must be accompanied by the writer's name and address. SHORT -WAVE ECHOES AND THE AURORA BOREALIS. Engineer of the B.B.C., and received a very courteous letter Sir,-In connection with the discovery of the abnormally from him in reply, which I am sure he will not mind you long retardations of short -wave signals discovered by Engineer publishing, and for that purpose I quote from it as follows :- Hals and so interestingly discussed by Dr. Beatty in your issue " We think that the difference between the quality of the of to -day, it seems of interest to enquire whether such pheno- transmissions of Daventry, 5XX and 5GB, which you notice, mena might be explained by purely terrestrial agencies. Every- is due to the latter station being of a more recent design. one must, find Professor Stormer's theory delightfully attrac- Daventry 5GB has a better frequency volume response than tive, but I think that other possibilities must be considered as 5XX, with the result that the overtones are transmitted in their well. correct proportions. The curve of musical frequency re- Abnormally long retardations of short -wave signals returned sponse from 30 to 8,000 cycles in the case of 5GB is practi- from the upper atmosphere were first described by A. H. Taylor cally a straight line ; that of 5XX, while not as good, is never- apd L. C. Young (Proc. Inst. Rad. Eng., Vol. 16, Nr. 5, 1928), theless reasonably satisfactory. We would not, however, char- yvho, in experiments carried out between Rocky Point and Wash- acterise the transmissions of 5XX as " woolly," though ad- ington, obtained retardations corresponding a mittedly this performance is not as good as 5GB. However, to distance of the transit of from 2,900 km. to 10,000 km., whereas the great difference is hardly discernible, except on apparatus that circle distance was only 420 km. In other words, retardations is extremely susceptible to good quality." over 20 times greater than we should expect As a matter of fact he is quite correct in stating that it is were observed. In only discussing these experiments in a paper read on a good set that any difference can be observed, and, before the Union of Radio Scientifique Internationale in Brussels on September 13th, course, many of the foreign stations exhibit just as bad a 1928, I pointed out that waves travelling. vertically upwards frequency curve, and this is unfortunately only too noticeable into on a good the ionised layer would be " reflected " at a point where set. the Have any of group velocity was reduced to zero, and that, if the gradient in your readers who take the Bournemouth trans- missions noticed that this station has recently very much this region was not large, the signal would he very - appreciably im- retarded there. proved the quality of its transmission ? Now, the retardations observed by Engineer Hals On my set, although I am only about thirty miles from it, I and Pro- could not get fessor St¢rmer are much longer than those observed by Taylor any good results unless it was transmitting from the Bournemouth Studio, or one of the and Young, and the question arises whether waves of 30 metres cafés, owing to very bad cut -off of the higher can remain travelling in the ionised layer for such a period of frequencies, but in the last month or so it 10 seconds and yet be of appreciable intensity when they reach has considerably improved, and is now quite a good alternative the ground again. (There is certainly no to 5GB on the lower waveband. J. B. KELLAR. difficulty in pictur- Salisbury. ing a path in the ionised layer along which it would 10 take November 14th, 1928. seconds for a signal to make a journey round the earth.) Some calculations I have made show that if there is sufficient ionisa- tion at very great heights, large retardations with only moderate Sir, -Mr. Gordon's letter on the question of transmission quality raises again the point which I have raised in your absorption may be explained. - columns There is also another possibility. If we on two occasions. When is that nice reticence on the think of the ionised part of the B.B.C. to be broken down and information layer as forming a kind of reflecting shell round the earth the some waves sent out from a concerning transmission quality vouchsafed to a long- suffering station may go round many times before public? they focus to produce a large signal In an address to the wireless section of the I.E.E., in a particular place. We Captain Eckersley gave some frequency response curves for know, from Quäck's records, that the attenuation for a single circumferential journey may 2L0, 5XX, and 5GB, but as yet no information has been given be surprisingly low. for any of the provincial stations. An inspection of the curves E. V. APPLETON. given by Captain Eckersley shows that Mr. Gordon is possibly Wheatstone Laboratory, King's College. November 28th, right when he says that the reproduction of 5XX transmis- 1928. sions is short of the higher audio frequencies. 5GB (when it is not subject to fading and distortion) gives at my position the TRANSMISSION QUALITY. most pleasing results. I some official Sir, -With reference to the letter dated October think that statement on the subject is long 26th, 1928, overdue, so would the B.B.C. mind giving the following infor- from Mr. A. K. Gordon in the November 14th issue of your mation : paper, the same variation can be observed in the transmission from 5XX and 5GB. (1) Typical frequency response curves for all the provincial stations, both on direct and relayed Those from 5GB are received here in transmissions. Salisbury pretty well (2) What degree of control is exercised, and, if this control perfectly on a good set using two L.S.5a valves in a stage of push -pull power were removed, what extra margin would have to be allowed in amplification with 300 volts H.T. and moving - receiver design to coil speaker, being crisp, take care of the .peakloads. clear and natural. (3) What improvements we might expect as regards transmis- Those from 5XX, on the other hand, are low pitched, woolly, sion quality and if any from the new regional high power stations. output is desired speech is almost impossible to (4) Do the B.B.C. consider that frequency response curves and understand. I have to detuse considerably to raise the pitch a measure of the degree of control exercised represent the whole t so that the higher frequencies are given more chance, as it story as regards measuring distortion in broadcast trans- were, although this is never necessary with 50B's transmissions, missions? W. S. which can be tuned in as sharp as you like and are still crisp. Manchester. After standing it as long as I could I wrote to the Chief November 14th. 1928. A 49

www.americanradiohistory.com WPpe@os5 DECEMBER 5th, 1928. 778 Waslca The actual number of turns will de- pend on the degree of selectivity re- quired and the constants of your aerial system, etc. ; the best position for the aerial tap can best be found by trial and error. oc oo An Inexpensive Receiver Is there any reason why the " Pentode Two " receiver should not be used with an ordinary valve in the output position? W. M. " The Wireless World " Supplies a Free Service of Technical Information. Provided that you do not require the high magnification and large output ob- to rules of the Department, which are printed below; these The Service is subject the a pentode valve, there is in the interest of readers themselves. A selection, of tainable from must be strictly enforced, no reason why an ordinary triode should interest is dealt with below, in some cases at greater length than queries of general not be You will, of course, be possible in a letter. substituted. would omit the connection to the screen grid Energising Current. your receiver. The fact that your terminal. I have an A.C. mains supply at 240 friend's set works well with the H.T. O O O unit would, suggest that this is the true volts. Which is, in your opinion, Th-e Pictures. using explanation. the most convenient method of of using some of my spare energise the pot magnet of a I am thinking this to components in the construction of a moving -coil loud speaker? The " Everyman Portable " Circuit. for operation with a pic- L. P. S. special set throttle control ture receiver. lVill you outline you will find it difficult to Is it possible to use the We think reaction circuit of the " Everyman briefly sonie of the requirements? I beat the arrangement which makes use of the con- Portable " (on a full -sized aerial) with am particularly keen on -receiving a small 6-volt accumulator battery S. T. J. nected across the winding, and charged an auto -transformer type of aerial foreign transmission. devices coupling, and, if so, where should The most important attributesof a set by means of one of the many reception are now The charger the tapping connections be made? I for long- distance picture which are available. and good sensitivity. should be able to deliver a current at wish to retain the waveband 'switch. high selectivity by the L. F. M. The latter quality is desirable, not. be- least equal to that consumed needed, but winding. Your proposed modifications can be cause a very strong signal is put effect if you use a three -pole because it is desirable to have a wide . 0 o into double -throw switch , for waveband margin of safety in order to compensate An Overloaded Eliminator. changing. The connections will be as in for fading. A smooth control of magni- as almost essen- illy set gave good results with batteries, Fig. 1, from which you will see that the ficátion may be regarded but since obtaining an eliminator signals are weak and badly distorted. Does this indicate that the set is un- suitable for use with a mains supply? The eliminator is beyond suspicion, 118 I have tried it with a friend's two -valve set with entirely satisfac- tory results. R. J. You do not give details of your set, or any information as to total anode current consumed by it, but we are inclined to think the trouble must be due to the fact that the eliminator is designed for a small output, and that its voltage falls very considerably when connected to

RULES. (L) Only one question (which must deal with a single specific point) can be answered. Letters must be concisely worded and headed " Infor- mation Department." (2.) Queries must be written on one side of the paper, and diagrams drawn on a separate sheet. A self-addressed stamped envelope must be enclosed for postal reply. (3.) Designs or circuit diagrams for complete receivers cannot be given ; under present -day conditions justice cannot be done to questions of this kind in the course of a letter. Figg. 1.-A throttle -controlled Hartley circuit with auto -coupled aerial and waveband L2 is the (4.) Practical wiring plans cannot be supplied switching. Lia and Lib represent the divided medium-wave inductance; or considered. long -wave coil. (5.) Designs for components such as L.F. doubt if you could better two chokes, power transformers, etc., cannot be third arm of the switch is arranged to tial. We supplied. change over the aerial connection to ap- FIX. stages with a detector and one (6.) Queries arising from the construction or propriate points on long or short wave L.F. amplifier, and would add 'that for operation of receivers must be confined to con- coils. These tappings should be made your purpose " quality " reproduction structional sets described in The Wireless receivers. at approximately the positions indicated; as it is usually understood is of no im- World " or to standard manufacturers' although there must, of course, Readers desiring information on matters you will observe that the aerial is joined portance, beyond the scope of the Information Depart- in such a way that the coupling turns be no marked tendency towards self - ment are invited to submit suggestions regarding are situated at the low -potential end of oscillation in either H.F. or L.F. ampli- subjects to be treated in future articles or paragraphs. the grid sections of the coils: fiers. A 50

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WEDNESDAY, DECEMBER I2TH, I928. VOL. XXIII. No. 24.

require the experience of the wireless engineer for Editor: HUGH S. POCOCK. solution. Assistant Editor: F. H. HAYNES. Some little while back came the application of the Editorial Offices: 116 -117, FLEET STREET, LONDON, E.C.4 principles of electrical sound reproduction to the gramo- Editorial Telephone: City 9472 (5 lines). phone, and this has now developed to a point where Advertising and Publishing Offices: the standard of reproduction of the modern gramophone DORSET HOUSE, TUDOR STREET, LONDON, E.C.4. is set by the performance of electrical reproduction. Telephl uc' City 2847 (13 Imes). Telegrams: I ?thae'orid, Fiell, London." Another direction in which the principles of sound COVENTRY : Hertford Street. rNearemr: °t'}r;iat, Covaotry.' Telephone: 5210 Coventry. reproduction have been applied to assist in the develop-

BIRMINGHAM : Guildhall Buildings. Navigation Street. ment of the new industry is exemplified in the talking re4prooi..: Aotoprees, llirudnghaol.- Telephone : 2970 and 2971 Midland. film, for which it will be generally conceded there are MANCHESTER : 260. Deansgate. very great possibilities. Since the technical problems 7elernm II;ITr %I...chest er. Telephone: $970 City 14 lineal. PUBLISHED WEEKLY. of the development of the speaking film are allied to Subscription Rates : Home, 17s. 4d. ; Canada, 17s. 4d. ; wireless, we may perhaps be permitted to make refer- other countries abroad, 19s. 6d. per annum. ence to the subject of the speaking film generally. Second t'.as, Matte: at Neu York. N.Y. 9s many of the circuits and apparatus des, rihed in these pages are covered by A New Technique Needed. patents, readers are advised, before making use of them, to satisfy themselves of Mal they mould not be infringing .patents. In spite the apparent possibilities, it does -not seem to its that the speaking film is achieving CONTENTS OF THIS ISSUE. the popularity to which its potentialities entitle it, and our own experience, after having seen and heard ex- EDITORIAL VIEWS .. .. ::71 amples of speaking films in various theatres in this RADIO GIFTS FOR CHRISTMAS 780 THE DISTORTIONLESS DIODE. BY IL F. SMITH .. 7,3 country is that, whilst the technical problems, such as IIIEGAVON ELIMINATOR. BY W. I. G. PAGE .. TALKING FILMS ...... synchronisation and quality of reproduction, are more CURRENT Topics or less taking care of themselves, and are bound tc PROGRAMMES FROM ABROAD...... A YEAR'S PROGRESS IN COMMERCIAL WIRELESS. BY I.T.C ot.. CIIF.T develop along the present lines to a state of compara- WORE CRAWLEY ...... rillt BROADCAST BRI:vITlt.s .. .. SO5 tive perfection within a short time, yet the part playec IdEADFRs' PIIOII.ENG 807 by the producers of the films leaves much to be desired. In our opinion, before justice can be done to the prin- ciple of the talking film, the present ideas of producers CHRISTMAS AND RADIO. of films must, in a large measure, give place to a ness CHRISTMAS comes round once again, and the technique, and instead of approaching the new principle question of how far wireless can help us in our from the idea of adding speech to a film, which has problems of the choice of gifts for our friends and been taken very much on the lines of a silent film, the for Christmas -time entertainment is with us. In " Radio speaking film should be developed, using the stage and Gifts for Christmas " in this issue we endeavour to sug- spoken plays as the basis but utilising to the fullest gest in the minds of our readers ideas for the choice of extent the advantages which the photographic film Christmas presents from amongst the products for offers, as a means of improving upon the scenery and which broadcasting is responsible. There is much that effects. is new and an immense variety of gifts at all prices, so The handicap of the theatre is that scenery and general that we think readers will find that their difficulties in effects are cramped within the limits and the possibilities the choice of Christmas presents can largely be solved of stage scenery ; the silent film depends largely for its by consideration of the possibilities which wireless offers. effect upon the fact that it is not restricted in this re- spect. COO O If the two could be combined, therefore, with the scenery and effects as secondary to the spoken words TALKING FILMS. of the play, and utilised to enhance the realism of the rÌHE scope of the wireless engineer is no longer whole, instead of merely adding the spoken word limited to the technical development of wireless and sounds to what is otherwise a silent film of a type trq,nsmission and reception of telegraphy and to which we have hitherto been accustomed, then in broadcasting, because new branches of electrical engin- this combination we foresee a much greater possibility eering are continually presenting fresh problems which of the development of a new art. s9

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7R0 DECEMBER rala, 1928.

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Suggestions for Every Purse and Purpose. T this season we are permitted which it is a token. No present the privilege of giving pre- could more completely satisfy this sents to our friends and rela- requirement than a wireless set, tions as tokens of esteem and which is certain to be in daily use affection. The giving of presents, now that broadcasting is per- if undertaken in the right spirit, can manently established as a public be made an even greater pleasure service. than receiving, for the choice of Another very sound reason for suitable gifts provides unlimited giving wireless is that one will be on familiar ground scope for the exercise of ingenuity and therefore much more likely to choose an article of and thought, and in its highest form is worthy to rank intrinsic value than if one attempted, say, to buy an as an art. etching for a collector of old prints, or a book for a The wireless enthusiast will want to approach the literary friend. It is a sound principle in buying problem of Christmas gifts in a logical and scientific presents to confine oneself to subjects with which one manner, and he will first make sure that he understands is fairly well acquainted, provided the recipient shares the fundamental principles underlying the choice of the to a certain extent the same interest. Here, again, we ideal gift. are on pretty safe ground in choosing wireless, for if It goes without saying that the present should satisfy our friends are not interested in the technical side òf a want. The element of the hobby, they cannot fail surprise is also important, to be interested in some and the pleasure experi- part of the daily pro- enced by the recipient will gramme transmitted by the be increased tenfold if the B.B.C. gift satisfies a need of Complete Receivers. which he was hitherto only subconsciously aware. It According to statistics is for this reason that all only one house in four is enquiries as to possible equipped with wireless, and requiremeïits should be there would appear to be made unobtrusively and ample scope for complete without putting direct receivers as Christmas gifts. questions. In choosing the type of receiver the temperament Permanence and Utility. of the person to whom it is The article chosen to be given must be taken should, if possible, be use- into account. Superlative ful and of a permanent reproduction and simplicity character in order that it of control are the qualities may serve to perpetuate most likely to win the "Superlative reproduction and simplicity of control are the a the feeling of goodwill of qualities most likely to win the appreciation of a musician." appreciation of musician. B TO

www.americanradiohistory.com DECEMBER 12th, 1928. vAnIlmo 781 WOpIld Radio Gifts for Christmas. - short -wave set with which to get in Long- distance reception can be safely ruled out and, touch with the Home Country through in the interests of quality, the selectivity need be suffi- 5SW? But before ordering be sure to cient only to separate the alternative programme get advice regarding the best type of stations. If possible the loud speaker should be the cabinet, insulating materials, and only visible part of the equipment, the receiver being batteries for H.T. and L.T. from installed in another part of the house with remote someone acquainted with tropical con- control. ditions. In general, a metal cabinet, A sensitive long- distance porcelain or bakelite in- receiver cannot fail to fire sulation, and inert cells to the enthusiasm and imag- be filled on the spot will ination of . youth. As it fulfil these conditions. in use at will be constant Accessories. all hours of the day, and possibly of the night, So far we have been headphones rather than a working on the assumption loud speaker would seem that our friends have not to be indicated in the as yet enjoyed the posses- .. interests of the remainder of a wireless receiver. of the household. High If it should happen that quality of reproduction is they have already installed not essential, but knife - a set, one's choice is limited edge selectivity is a sine to accessories. On second A sensitive long- distance receiver cannot fail to fire the qua non. enthusiasm and imagination of youth." thoughts, " limited " seems Between these two hardly the correct word to extremes will be found the requirements of the average use, for the number of " gadgets " suitable for addition family, namely, the ability to receive at all times two to existing receivers is well -nigh unlimited. A visit to alternative programmes at sufficient volume for the your friend's house and an unobtrusive examination of living room, together with the the set will suggest many possibility of picking up one possibilities. It may hap- or two Continental stations pen that the set is not as a matter of interest when functioning. You enquire circumstances are favourable. the reason. The accumula- A wide selection of receiving tor is away being charged. sets satisfying these require- Item Number One, a spare ments will be found at prices ranging from L7 to rio. accumulator for use while Before making a final choice, it would be as well to the big one is being charged. The capacity should be enquire into the probable cost of upkeep in such that the maximum discharge rate is order that the recipient may not be involved equal to the current required by the set, and in an expense beyond his means. In this the plates should preferably be of s the respect mains -driven receivers show to dis- " mass " type, for it will be called upon to tinct advantage, but the nature of the mains hold its charge for long periods. Make sure supply must be ascertained with meticulous that the voltage corresponds with the type care before placing an order. Some details of valves in the set, or the gift may do more of the type of aerial it would be possible damage than it is worth. A question as to to erect and the distance of the nearest whether 2 -, 4- or 6 -volt valves arc being B.B.C. station should also be noted for the information used is very frequently asked as of the dealer to whom the order is a matter of interest, and will not entrusted. * arouse suspicion. To make quite certain of successful While on the subject of results and to be independent of batteries, may we suggest a problems relating to aerial systems hydrometer as a means of keep- and power supply, the self- contained ing cells in good condition, and portable set should be seriously con- so obtaining the maximum -4 sidered. The upkeep cost in the matter service? of H.T. batteries is naturally higher than a permanent Then there are accessories mains- driven set, but against this the advantages of which extend the usefulness of a receiver beyond the portability are obvious. It makes the reception of broadcasting. An elec- ideal present for the outdoor type of trical gramophone pick -up, for in- person. stance, or-yes, why not ? -a complete Finally, a hint to those with relatives picture receiver. and friends in distant parts of the If dry cell H.T. batteries are knowr Empire. What finer present than a to be an expensive item in the upkeep

8 if

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782 WAp@fl@O DECEMBER 12th, 1928. WalfIl Radio Gifts for Christmas. - conform exactly to specjfication. If possible try of a quality receiver using power valves, an H.T. to obtain full particulars of the additional com- mains eliminator is certain of grateful acceptance. ponents required for his next set, but if this is The choice of a suitable type, however, can hardly impracticable there are many components to be undertaken without a consultation with the choosy from which are of general utility and are owner of the set, for the fullest particulars of the certain, sooner or later, to fill a want. Amongst receiver as well as the nature of the supply must other things we would suggest a pair of slow - be given when ordering. motion dials made to fit tin. spindles, variable If you already possess a detailed knowledge of condensers of well -known make, either of 0.0003 the receiver in question and to your certain know- or 0.0005 mfd. capacity, a good audio -frequency ledge it has remediable faults, the gift of a suit- transformer, ratio about 3.5:1, a set of non - able accessory is a tactful way of pointing out the microphonic valve holders, and large by -pass con- deficiency. A loud speaker whose densers of, say, 2 mfd. capa- performance is being marred by an city. excessive direct current through Many home- constructed sets the windings will be assisted in do not get much farther than functioning properly by a filter -feed the panel and baseboard layout unit or output transformer. Selec- stage, but when one is made tivity can often be improved by which looks like taking permanent the use of a well- designed unit con- form, the present of a suitable nected in the lead -in wire. Recent cabinet will add the finishing improvements in valve charac- touch. teristics suggest another possibility, but new and more It is possible to construct a powerful output valves should only be given where the complete wireless set with no more source of H.T. current is the supply mains. elaborate tools than a soldering iron, a pair of pliers, and a screwdriver, but Aids to Better Reception. work of this kind is little more than A triple -range measuring instrument assembling, and is generally undertaken will give pleasure to the man who takes only by people who wish to equip them- an interest in watching over the per- selves with wireless at the lowest formance of his set. The possible cost. ideal instrument for The man who takes a modern circuits would pride in his hobby is pre- have t h e following pared to go to any length in ranges : o -200 volts, building his sets 'according 0 -7.5 volts, and o -35 to his own ideas. This will milliamperes, but the mean that he will have to ranges could be modified construct many parts from to the requirements of the raw material, and his receiver in use. equipment of tools will The experimenter is an experienced critic, and to win his Numerous applications for approval components must conform exactly to specification." expand accordingly. Many an instrument of this type useful tools specially de- will be found in an article which appeared in the issue signed for wireless work are available and these, in of this journal for March 28th, 1928. Incidentally, may addition to such standard appliances as hand drills and we remind our readers that The Wire- electric soldering irons, provide less World is an indispensable acces- ample variety for choice. sory to the full enjoyment of any In conclusion, may we remind branch of wireless activity, and that a readers that time is,. now getting year's prepaid subscription will be short, and to make certain of acceptable alike to the novice and the delivery before Christmas orders expert. There is also the comprehen- should be placed at the earliest sive range of text books and the possible moment. The more popular " Wireless World Diary " from which to make a choice. the receiver or component the greater the need for prompt action ; the demand for these articles The Experimenter. will increase enormously as Christmas draws near, and Those of your friends who are experi- although the rate production may be menters and make a hobby of building adequate to meet the demand the packing their own sets will no doubt appreciate and despatching departments will.be over- components as Christmas gifts. These taxed. These departments are the bottle- must be chosen with the utmost care if neck through which production flows, and they are to be of any use, for the experi- any help which the public can give to menter is an experienced critic, and to relieve the last minute strain will be win his approval components must greatly appreciated by manufacturers. B i2

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Practical Applications of the Twozelectrode Rectifier. By H. F. SMITH.

IT is more than doubtful if the ear can detect dis- consequently its circuits are free from interaction, and tortion due to a properly arranged anode bend recti- the possibility of low- frequency reaction-which, if fier, even when it is followed by the best amplifier present, is certain to introduce serious distortion, if not and loud speaker, although it must be admitted that actual " motor boating," or oscillation -is very con- the defects of this method of recti- siderably reduced. This is especially fication might become noticeable Distortionless ; damped ; decoupled ; true where anode current is derived with a considerable increase in the ; in these three words may be summed up from an eliminator although signal depth of modulation at the transmit- the more important advantages and dis- impulses can be diverted from re- ting station. The diode detector in advantages of the modern version of the sistances and impedances common its best form gives a rectified output two-electrode detector, for which an ordin- to a number of circuits, thus pre- strictly proportional to input voltage ary three- electrode valve is used. venting interaction, this end is at- of over a wide range, but in spite In many cases diode rectification con- tained only at the cost of complica- this advantage it would appear to fers benefits that more than outweigh its tion and considerable expense. On have an application only in cases shortcomings, and its usefulness is by these grounds alone a good case where academic perfection is re- no means confined to the more ambitious could be made out for the diode, quired, were it not for the fact that type of receiver. and it should not be neglected by it has, apart from its excellence as a users of two -stage L.F. amplifiers, rectifier pure and simple, another who depend for anode current on a property which is even more important under present - mains supply, or even on an H.T. battery of high day conditions. It requires no high- tension voltage, internal resistance. and, indeed, is completely isolated from the anode cir- It cannot be denied that the sensitivity of the diode cuits of the L.F. amplifying valves in the receiver; is low, and it is therefore most likely to appeal to those

0001 mfd t st L.F. DET. 001 mfd

L.T. + (i) (2)

Figs. i and 2. -The conventional parallel- connected rectifier circuit, and (Fig. 2) the series arrangement. In either, the anode may be joined to a tapping point on the coil, thus increasing both selectivity and volume. B 13

www.americanradiohistory.com !!?4`°!f h''

L.T. natively, an H.F. choke can be inserted in the same + position.. A rectifier of this kind is not quite so perfect over a wide range of inputs as is the first -mentioned, (3) but if it is followed by an efficient 2o,000 -ohm valve, coupled in its turn to the output valve by means of a Fig. 3. -A test circuit for diode rectification, without H.F. or good transformer, it will be distortionless on H.F. in- L.F. amplication. puts, which, after detection and amplification, will fully There are several methods of using a modern three - load up any ordinary output valve with the H.T. volt- electrode valve as a two -electrode rectifier, but in every age customarily applied. case it is usual to neutralise the space charge by the A diode detector, like _ a galena crystal, imposes a application of a steady positive potential (derived from very heavy load on the tuned circuit which precedes dry cells or an accumulator battery) of some 9 or io it, and it is partly for this reason that it has such a volts to the grid. Signal voltages are impressed between bad reputation for sensitivity. Its shortcomings in this anode and filament. As is well known, a valve passes respect can be overcome to a great extent by using

H.T.+ 001 mfd

(4) (5)

Figs. 4 and 5.- Rectifier preceded by screened -grid H.F. stage with step -up transformer: Fig. 5 shows a step -down coupling with tuned primary. In these and the following circuits . C is the coupling condenser ; R, H.F. stopping resistance : R1, grid leak. These components may have conventional values. 8 I.}

www.americanradiohistory.com FPS'.:1t

DECEMBER 12th, 1928.

' the experiment, a coil The Distortionless Diode. - existing conditions. To make specially designed tuning circuits with a higher ratio of with seventy turns of No. 26 D.C.C. should be wound capacity to inductance than is customary, but this ex- on a Sin. former with a tapping at the twenty -fifth turn pedient is hardly likely to be widely popular, and it from the earthed end. This is joined up in the manner ,t will generally be considered preferable to use trans- shown, and if really loud phone signals are obtained formers, etc., of conventional design, and to join the the experimenter can rest assured that the rectified anode of the detector to a tapping point on the coil at current obtainable, applied to an amplifier as described such a position that approximately one -third of the in an earlier paragraph, will fully load up a normal 4 total number of turns are included in circuit. It is not output valve, even if it is of the super -power variety possible to lay down a hard -and -fast rule, but if a with an anode voltage of 13o or so. Under these con- tuning condenser of 0.0003 or 0.0005 mfd. is used, this ditions the detector will be working distortionlessly, connection will generally be sufficiently near to the but where more ambitious requirements are to be satis- optimum point for all practical purposes. fied it will be necessary to precede the detector by a Almost any ordinary valve will work well as a recti- stage of H.F., and preferably to use the rectifier circuit fier, but a " general purpose " type, with-very given in Fig. I. of 20,000 ohms, and a roughly -a rated impedance Adding H.F. Amplification. voltage factor of 2o, is the safest and best, particularly for the circuit of Fig. 2. With regard to sets for long -distance work, we must To improve the performance of the rectifier it is face the fact that, as compared with an anode bend or desirable to apply a slight positive bias -of something grid circuit rectifier, the diode does reduce both sensi- less than a volt-to the anode of the valve. This can tivity and selectivity. The position is not hopeless,

H.T.-1- A

(b) (7)

Figs. 6 and 7. -The parallel- connected diode following an H.F. stage with tuned anode coupling, and (Fig. 7) the series arrangement connected to a neutral.sed transformer of conventional design. most conveniently be done, as shown in the diagrams, as quite fair results are obtainable with a single H.F. by joining the low -potential end of the plate -filament stage if it is really efficient. We must not forget, how- circuit to the slider of a potentiometer, the windings ever, that reaction from the detector anode circuit is of which are connected across the L.T. battery. The no longer obtainable, and that this valve does nothing adjustment is best made when listening to signals arti- towards magnifying the applied signal voltages. Con- ficially weakened by detuning or otherwise. sequently, we must regard the addition of a second H.F. stage as almost essential when long -range reception A Trouble -free Domestic Set. is our aim. The most obvious, and certainly the most attractive, In Fig. 4 is given the connection of the simpler form. i1 application of the diode is to a simple short -range set. of rectifier when used in conjunction with a screened High- frequency amplification is by no means essential grid H.F. amplifier. The coupling transformer may be at distances of a few miles from the transmitter, unless of conventional design, but, as before, damping should the detector anode to a point on requirements as to volume are . above the average. By be reduced by joining setting up the circuit shown in Fig. 3 it is an easy the secondary which will result in the inclusion of about of turns. matter to decide whether the rectifier, without H.F. one -third of the total number 7 amplification, will give the required performance under Another device for coupling the rectifier to an S.G. B 15

www.americanradiohistory.com 7x6 oIpiglsoo DECEMBER 12th, 1928. nÌfOic'Ilcl The Distortionless Diode. - be preferable to prevent the possibility of interaction. amplifying valve is ; shown in Fig. 5 this consists of a There is no reason why a diode detector should transformer with a not tuned primary and a step -down be preceded by a stage of neutralised H.F. amplifica- ratio of about 3: i. This arrangement is rather less tion in conjunction with an ordinary selective than that valve. Its con- discussed in the previous paragraph, nections are given in Fig. 7, from which it will but it has the be seen advantage that the number of connections that, as usual, the rectifier anode is joined brought out to a tapping from the transformer is reduced by one - on the coil. Due to the damping which must inevitably an appreciable gain where waveband switching is to be be present in spite of this precaution, included. there is little point in using a transformer with a Litz -wire secondary. The e e Kirkifier " detector circuit may be linked to In conclusion, it may be pointed an out that in circuits H.F. valve through the couplings shown in Fig. 4 such as those shown; it is possible and to control volume Fig. 5, or, if preferred, it may be used in con- over a reasonably wide range by dimming junction with the detector a tuned anode arrangement as shown in filament ; measurements show Fig. that a reduction of emis- 6. Unfortunately, this scheme of connection does sion does not cause any real change not completely in the linear rela- isolate the L.F. grid from the H.T. tionships between input H.F. voltage supply, and and rectified the use of an H.F. transformer, in spite current when the valve is operated under conditions of its slightly increased complication, is considered to as already stated.

CLUB REP ORTS New Society at Swindon. ha ii The inaugural cless Society on November 21. The meeting of the Swindon and lecture was of District Radio Society was held on November great topical interest and showed how an entirely new field had been opened 27 at Maxwell Street Schools. Following the TOPICS to the experimenter. up election of office bearers the evening was de- Several pictures were voted to shown, and the apparatus was described in the comparison of various moving coil detail. There was loud speakers demonstrated on a simple and an enthusiastic discussion. inexpensive -valve Hon. Secretary, Mr. R, C. A. llayucs, 159, three receiver. Lordship Lane, N.22. The Society meets every Tuesday at 7 p.m. sew members will be welcomed. Picture Broadcasting Described. 0000 Hon. Secretary, Mr. Pidgeon, 130, Princes Mr. F. H. Ilaynes-, Assistant Editor of Wrong Methods Demonstrated. street, The Wireless World, lectured on Picture The Wireless Swiudcm Broadcasting World Five was demonstrated 0000 " at the meeting of the Totten- in a novel manner by Mr. E. L. Cumbers, lion. Song and Dance. Secretary of the South Croydon and District A Radio -Gramophone Concert and Dance, Radio Society at the last meeting. Mr. Cumbers open to the public, is being organised by the showed how easy it was to operate the set in Bec Radio Society, Bec School, Beechcroft Road, FORTHCOMING EVENTS. the wrong way, explaining how various mat Balham, S.W.17. This interesting event will be WEDNESDAY, DECEMBER 12th. adjustments produced distortion and similar re- held on Saturday next, December 15, at 7.30 ilfuswell Hill and District Radio Society. sults. Subsequently the set was given a fair p.m. at the School. Loud speakers and -At 8 p.m. At Tollington School, trial, and Continental stations were received amplifiers, kindly loaned by Messrs. S. G. Tethcrdorcn. Demonstration of Radio and in plenty. An interesting five -valve portable Brown, Ltd., will be used together with an Electrical Novelties, by Mr. Leonard set way demonstrated by Mr. Fairweather, who H.M.V, automatic gramophone and records. Hartley, B.Sc. entered the clubroom carrying what looked like Tickets, ls. 3d. each (reserved Is. 6d.), are Wigan Technical College Radio Society.- - an ordinary attaché case. 2LO was received obtainable from the Hon. Secretary, Mr. A. L. Social evening. at excellent strength. and more Tottenham Wireless Society. 8 p.m. than one Odell, 171, Tranmere Road, S.W,I8. -At European station could be tuned in without o 0 0 0 At 10, Bruce Grove, N.19. Lecturer any delay. "Quality in Reproduction," by Mr. S. Quartz Crystals. Smith. Hon. Secretary, Mr. E. L. Cumbers, 14, Camp- Mr. A. Hinderlich recently lectured before Edinburgh Radio Society. -At 8 p.m. At den Road, South Croydon. the Guiders Green and Hendon Radio Society 117, Genrgc St. Demonstration of ".4 0000 Dn " Quartz Crystals and Their Application to Complete Electric Radio- Gramophone A Good Record. Wireless." The lecturer described the oscil- Equipment," by Mr. H. W. Gambrell (of At the first annual lating properties of quartz when placed between the B.T.H. Co., Ltd.). general meeting of the two plates subject to an electrical discharge, Royal Society of Arts. -at 8 p.m. At Slade Radio (Birmingham) on November 29, John Street, Adelphi, W.C.2. Lecture: the Secretary's report disclosed that the num- and explained how this property was utilised in bers on the calibration of wavemeters. "Applications of Electricity to Medical the membership roll had grown from Practice," by Mr. Cl. G. sixteen to eighty -seven in Hon. Secretary, Lt. -Col. H. A. Scarlett, D.S.G., Blake, one year. The F.Inst,P. Chairman: Sir Oliver Lodge, number of lectures and demonstrations given 60, Pattison Road, N.W.2. M.A., LL.D., D.Sc., F.R.S. during the year totalled o o o 0 thirty -four, of which THURSDAY, DECEMBER 13th. more than half were contributed by members of Ultra Selectivity. Stretford and District Radio Society, -At the Society. A number of 8 p.m. At 6a, Derbyshire Lane. social events had The question of selectivity occupied the atten- also been held. The Society is engaged in tion of members at the last meeting of Demonstration of Moving Coil Loud the Speakers. by the Star Engineering Cu. forming a valuable collection of apparatus and North Middlesex Radio Society. The discussion Ken.sin "inn 8'n Precision instruments, and not the least im- was opened by Mr. E. H. Laister, who showed At 136, .Holland Park Avenue Demon- portant activity is attending to sets belonging how the growth in the number of wireless stration of a Straightforward Broadcast to blind listeners. The ensuing year is looked stations in the last few years had emphasised Receiver, by Mr. Maurice Child. forward to with every confidence. and a hearty . the need for greater selectivity in wireless re- Slade Radio (Biros myna,,, . A ., ,11 welcome is extended to new members. Particu- ception. The effect on quality of highly selective the Parochial Hall, Broomfield Rond. lars can be obtained from the Hon. Secretary, circuits was discussed, and the use of several Erdington, Members' Night. Mr. H. Clews, 52, St. Thomas Road, Erdington, stages of ILF., each of moderate selectivity, FRIDAY, DECEMBER 14th. Birmingham. was advocated with the object of obtaining a South Manchester Radio Society. -At the 0000 flat -bopped resonance curve. Mr. T. Tagent Co- operative Hall, Wilmslow: Road, Dids- Simplicity in Control. and anode rectifica- bury. Demonstation of a Gramophone mentioned the effect of grid Pick -up, by Mr, F. W. Bissett. When, recently, the South Woodford and tion respectively on selectivity, pointing out the SATURDAY, DECEMBER 15th. District Radio Society obtained the loan of a disadvantages of the former method. Golders Green and Hendon Radio Society. Music Magnet receiver from the General Electric Mr. A. J. Webb, M.A., B.Sc., a visitor from -Visit to the National Physical Labora- Co. it was demonstrated by Mr. H. O. Crisp, who the Croydon Wireless Society, described a 're- tory, Teddington.. had never seen the ássembled instrument be- ceiver embodying no fewer than six tuned MONDAY, DECEMBER 17th. fore. Its simplicity of construction and control circuits. The selectivity was such that the Hackney Radio und Physical Society.-At were no handicap to performance, as the de- tuning in of even the local station was a con- 8 p.m. At the Electricity Showrooms, monstration proved. Distant transmissions siderable problem! Loner Clayton Road, E.5. Evening were tuned in with good quality, and re- Devoted to " Improving your Moving Coil the Hon. Secretary. Mr E. iL Laister, " End - Loud Speaker." action was handled with ease. eliffe," 7a, Station Road, VI iuchmore 11111, Hon. Secretary. Mr. E. J. Tnrbyfleld, " The N.21. Nook," Alexandra Road, South Woodford, E.18. B 16

www.americanradiohistory.com DECEMBER 12th, 1928. Wp@llism 787

of Universal An H.T. Eliminator for A.C. Mains with Metal Oxide Rectifier Application to Receivers with Three and Four Valves. By W. I. G. PAGE, B.Sc. to impede the low - somewhat disquieting fact that the most faith- retain the necessary high inductance T is a likewise expensive. The rendering of speech and music in wireless is frequency ripple current are ful a large margin of safety closely associated with special valves whose greed resistances used must also have do not heat up with the watts for anode current does not seem to diminish as time to ensure that they principles of power output are such that consumed. goes on. The can be quite unpleasant at the signal should produce a large change in anode cur- To prevent shock, which the whole equipment has been rent, but it is patent that the current cannot swing to voltages well over 200, ingenious earthed all -metal safety value below zero. The inference, therefore, is that mounted inside an a when the lid is opened the mains the current must be large before any signal arrives so box by means of which at both poles by a switch, thus leav- as to accommodate the fluctuations within the limits of supply is broken ing all the exposed contacts " dead." Fuses blowing the valve's characteristic. lead in the loud speaker reproduction and a at one ampere are provided in each main's Thus, satisfactory against short- supply appear to be inseparable. The lid of the box, and afford a protection generous H.T. Thus the equipment as a case for mains operation, where such is possible, be- circuit or serious overload. whole can be said to conform comes clear when it is appre- to the I.E.E. regulations, milliamperes at a specially for the MEGAVOX- ciated that 20 Although designed and should satisfy the most pressure of 200 volts for 25o THREE receiver, which on account of its remark- able performance has achieved such popularity, stringent requirements of any hours represents a Board of Trade article with very but 6d., the eliminator described in this lighting company. The total ex- unit costing perhaps small modification can be used with almost any been considerably the distortion and hum are penditure has whilst dry batteries giving receiver. Motor -boating, of a entirely absent and a generous output of 100 mA. increased by the adoption same output would cost over 3os. -oxide bridge will at 200 volts is obtainable. Westinghouse metal True, the mains equipment cells arm, of the rectifier with eighty per waste a small fraction and can be regarded the comparison still remains very striking. which has some striking properties, energy, but of practically unlimited life The eliminator, after a short period, should thus pay as a sound investment spite of its rather high cost, which we must with no upkeep costs. for itself in has the high efficiency of nearly 70 to justify. Liberties cannot be taken with As a rectifier it now attempt its extremely low internal resistance, as apparatus connected to lighting mains, and, to prevent per cent., and all components have compared with that of other forms of rectifier, provides breakdown due to poor insulation, curve. The volt- have the makers' guarantee that a most satisfactory voltage regulation to be chosen which to the load, so that been tested at voltages far above that to age drop is practically proportional they have to a straight line. The bridge which they will be subjected in the eliminator. the curve approximates formation prevents any reverse current whatsoever, and High Voltage Surges and Test Pressures. provides full -wave rectification. When the latter form At the moment of switching the H.T. supply on or of rectification is obtained from a valve, a bridge ar- off there will be, due to the presence of smoothing rangement cannot conveniently be used, and a centre- of which equipment, voltage surges 1 which may at " make " tapped transformer is employed, the outers rise to a value not exceeding twice that of the working may have the large potential difference of some 48o voltage, whilst at " break " a pressure may be reached volts, whereas the R.M.S. volts across the untapped which is even three times greater than the working volt- secondary of a transformer designed to precede a metal age. Condensers which have been tested with surge rectifier are not more than a few per cent. above the voltages of 1,000 cannot be manufactured cheaply, and primary voltage. A word of warning is here neces- chokes which must under given D.C. load conditions sary concerning any attempt to dissemble the rectifier. bolts holding the treated copper discs have been 1928. Surges in The ' See Experimental Wireless, November, adjusted to give a correct pressure for opti- Eliminator Smoothing Circuits," by A. G. Warren. carefully ß

www.americanradiohistory.com 788 Wfinhoo Wald DECEMBER 12th, 1928. Megavox Eliminator.- mum performance, and should not be touched. A R1 slight temperature rise lgs r +H.T.4 takes O place during operation ; CH therefore, ventilation FUSE R3 i +H.T,3 is LAMP p necessary, precluding the mounting of any compo- +H.T.2 nents actually touching the CH.2 sides or top :: R 8 of the ap- AL .0 + H. paratus. C 4 R7 With a complement of .. Vie T T5 -H T. eighty cells in each of the [. T°6 T 0 four arms of the bridge, RECTIFIER the FUSES voltage rise which occurs on open circuit is not of suffi- SWITCH cient magnitude to harm the rectifier, while damage EARTHED METAL CONTAINING BOX from short -circuit or over- load is prevented A.C. by inter- MAINS posing a sensitive flash lamp fuse between the trans- 1. -The circuit arrangement of the eliminator. metal safety -box One -ampere fuses are fitted to the lid of the former and the rectifier. and a sensitive fuse lamp blowing at about 180 mA. is connected in one lead between the transformer and rectitler. Value of The lamp CH2, components are as follows: CHI, 20 henrys; used is rated for 32 henrys; C,, C; 2 mfd. condensers, 1000 volt test; C4, two 2 mfd. condensers in parallel, 1000 volt test ; C2, C3, C4, C7, 2 mfd. condensers, 500 6 volts, ioo volt test ; R1, 5000 ohms ; R2, 10,000 ohms ; mA., and fuses R3, 10,000 ; R4, 30,000 ; ohms R5, 20,000 ohms ; R4, 20,000 ohms ; R7, 30,000 ohms. at about 18o mA. (see photograph). Not the least attractive feature of the length of time, transformer so that the ample latitude of this bat- -rectifier combination selected is the fact that tery substitute to accommodate the present the anode requirements eliminator is capable of feeding almost any of almost any valve should set containing have considerable appeal. up to four valves, the requirements of The reader will be able to judge from the foregoing which are not more that than ioo mA. at 20o volts. Very it is almost impossible to design a highly efficient A.C. few experimenters are content with one receiver for any H.T. eliminator of almost unlimited life conforming to

'MO 00-`- L 0e V2 V EL, ,--.L e C =C

L4 i DET. SWITCH 3 o-. L.G. C B2- EARTH e LINE C1 C 12 H1 B3 4V r4 130V 80V. 150 V. 03mA AND 0-5mA 1.smA 3.0mA P.M.14 P.M.14 P. M.4 DX í150V.21mA O a P.M. 24 -H.T. +H T.1 +H.T2 +H.T.3 +H.T.4

Fig. 2. -The circuit diagram of the Megavox- the calculation Three. A separate H.T. lead to the detector plate (H.T. + 3) is necessary. To simplify of resistances in the mains equipment the valve currents and voltages have been marked against their respective terminals. The pentode feed is now H.T. + 4. B 20

www.americanradiohistory.com DECEMBER 12th, 1928. WATSIl®00 789 WopIld machine, and found to have in the Megavox Eliminator.- on an Ondograph suitable for almost any receiver without detector output feed a ripple voltage of a small fraction regulations and comparable an expensive outlay. of a volt R.M.S., so small, indeed, as to be in an article of limited length to give with the slight fluctuations that occur in H.T. batteries." It is difficult in d'être for every component and every circuit The circuit of the Megavox -Three is again given the raison with the ex- detail, and the writer must reluctantly resort to what Fig. 2, and is identical with the original, another author has been pleased to call " Brad - shavian Acrobatics." This article should be read in con- junction with two other ar- ticles,2 firstly, to see why it is essential to use the series anode feed scheme (and not a common potential divider across the mains) to prevent motor boating or back - coupling, distortion, and loss of amplification ; a n d , secondly, why separate local potential dividers are neces- sary when it is required to drop volts for the feed to the screen of a screened grid valve and an anode bend de- tector. The eliminator cir- cuit about to be described (Fig. 1) has resistances values and a slightly modi- fied smoothing equipment to suit the Megavox -Three re- ceiver (constructional details of this receiver were given on September 19th), but by one or two simple changes, not in any way affecting the dimensions or lay- chassis eliminator chassis removed from the metal safety -box. The be View of the components and co mplete numbered resistance holders. out, the equipment can flash lamp fuse can be seen at t he top of a small wooden pillar. Note the altered to suit almost any detector is brought the concluding instal- ception that the anode feed of the receiver, as will be shown in the terminal strip and week's issue. out to a separate terminal on ment of this article in next pentode feed now becomes of every H.T. feed and to the labelled H.T. +3. The Due to the separation reason for this slight alteration is due smoothing equipment embodied, neither motor H.T. + 4. The liberal difficulty of preventing back -coupling with a lead boating, distortion, loss of amplification, nor hum were to the common to the plates of the H.F. valve and the detec- tor. No other modifications whatsoever are needed in the receiver ; the resistances r4, r;, rs, and r, remain, as also do the condensers C8 to C12. The resistance WESTINGHOUSE dotted lines in the original diagram, is METAL OXIDE r8, shown in RECTIFIER not needed. Tuned Anode and Difficulty in Smoothing. Against the H.T. positive terminals of the receive' the marked the names of the valves used, to- Fig. 3. -The circuit arrangement used for the prep'ration of (Fig. 2) are voltage regulation curve. gether with the anode currents taken at the optimum H.T. voltages, assuming that the grid biases applied discernible even when using a moving coil loud speaker, those advised in the original low are in accordance with one of the great attributes of which is response to on the eliminator are marked Brake article. The terminals frequencies. By courtesy of the Westinghouse with the terminals on the receiver, i.e., the eliminator was tested to correspond and Saxby Signal Company, H.T +4 is connected to H.T. +4, etc., and the values in Eliminators." The ll irth ss World, 2 " Back Coupling line amplifier us used to amplify the ripple cons 1928. " Dropping Volts." 4'he Wireless 3 A straight September 26th, an reading is obtained. ald. November 28th, 1928. posent before Ondograpli

B 2 l

www.americanradiohistory.com 790 ME4®00 DECEMBER 12th, 1928. W®IfIld Megavox Eliminator-

LIST OF PARTS. 1 Safety -box with fuses and double -pole switch (Ferranti). 1 Resistor holder for fuse lamp (Burndept). I Mains transformer (stale mains voltage and frequency when 1 Flashlamp bulb, 6 volts 100 mA. (Bulgin). ordering) (Type E.M.1. Ferranti.) 5 Shrouded terminals ; H.T. - ; H.T.+ I ; H.T. -(- 2 ; H.T. -L 3 ; 1 Metal oxide rectifier ; (Type "H.T.I." Westinghouse Brake & H.T.+4 (Igranic). Saxby Signal Co.) 5 Spade ends (insulated) 4 red, 1 1 32 -henry black (Lisenin). choke (Type 658 Pye). 5 ¡vorine flex wire labels; H.T. 1 -henry -; H.T.+I; H.T.+2; H.T. -f.. ?; 20 choke (Type 664 Pye). H.T.+4 (Bulgin). 7 Wire -wound resistances bi-duplex with clips ; 5,000, 10,000, I Ebonite terminal strip 8" x1" X 10,000, 20,000, 20,000, 30,000, 30,000 ohms. (R. I. r. & Varley). Wire, systoflex, I" plywood 24" x 10 ", lampholder adaptor or 8 2 mfd. condensers, 4 type C1, 1,000 volt lest ; 4 type C2, 500 wall plug, etc. volt test (Ferranti). Approximate .cost of all parts, £12. In the " List of Parts " included in the descriptions of THE WIRELESS WORLD receivers actually used by the designer and illustrated are detailed the components in the photographs of the instrument. Where the designer considers it necessary that particular components should be used in preference to others, these components itself. In all are mentioned in the article other cases the constructor can use his discretion as to the choice of components, provided quality to those listed, and that he takes into they are of equal consideration in the dimensions and layout of the set any variations in the size of alternative components he may use.

of the voltage- dropping resistances have been so chosen The tuned anode coupling in the Megavox that the H.T. currents provides are correct to each valve. a path for ripple current from the plate of the screened The pentode feed is passed through the smoothing grid valve to the most vulnerable part of the receiver choke CH1, which has - an inductance of about 14 henrys namely, the grid of the detector special precau- at 21- mA., but has -and the advantage of the low D.C. tions have to be taken to prevent any ripple resistance of 300 ohms. from The resistance R1 augments reaching the terminal H.T. +2 of the eliminator. the smoothing in conjunction The with Cl and drops the choke CH; has an inductance of 32 henrys necessary volts. The pentode when the screened grid circuit is specified D.C. current is passing through it, and to- isolated by the de- coupling resistance and condenser gether with the combination already C5, R5, and C5, adequate in the receiver. In order to cope with the two smoothing is obtained. Because anode currents of the elaborate of o.3 mA. and 3.o mA., respectively, smoothing required preceding tuned anode for anode bend and leaky coupling, it grid detection, the potential is possible that there will be a general tendency towards divider R2, R R4 in the H.T. +3 lead has been given the use of tuned transformers rather with screened grid valves. a low total value, so that the current passed is For the sake of cheapness, more satisfactory comparatively large, which filtering, was explained as essential in and because there is no question of L.F. coupling at this the article entitled " Dropping Volts." One limb (i.e. point, the plate of the screened grid valve, as well as the screen of the same valve, is fed from one potential divider of three sections -R,, RE, R whose`junction points are connected to C, and C7. Obtaining the Regulation Curve. It now remains to describe the method of ascertaining the D.C. volts developed across the 4 mfd. condenser C4, which have to be broken down to the values shown against the terminals in Fig. 2. The rectifier produces a pulsating uni- directional current which can be regarded as a pure D.C. current with an oscillating component symmetrically superimposed, but as the rectifier has in- ternal resistance it is quite clear that a load will cause a drop in volts. A condenser by passing part of the oscillat- ing component can act as a load and reduce the voltage 10 20 30 40 50 60 70 80 90 100 output just as a resistance can do the same thing. In D.C. M LL AMPERES order to obtain a reasonably true reading with a moving coil D.C. meter of the average D.C. output available at Fig. 4. -The voltage regulation curve obtained from the trans- the input of the filter, it is necessary to subdue former- rectifier combination used in the eliminator. The H.T. as far current for the Megavox is about 26 mA., but together with the as possible the oscillating or ripple current by including potential divider losses the total load is about 33 mA., at which a voltage of approximately 265 is obtained. the meter after the 4 mfd. condenser, which incidentally- acts as a reservoir. If an attempt be made to damp ou_t the series limb) of this potential divider has been split more thoroughly the ripple current C4 into two at by increasing portions with a condenser C2 at the junction the capacity above 4 mfds., it will point act as a short circuit to assist smoothing% Another condenser C, between to ripple and damage the rectifier by overloading the two limbs it. of the potential divider gives a sufficient The curve showing the relation between total current filtering to dispense with a choke in the detector feed. consumed by the set and voltage available at the filter B 22

www.americanradiohistory.com DECEMBER I2th, 1928. Mragoo 99T G`'Iuptcl concluding instalment of Megavox Eliminator. each valve will be given in the - will also the modifications necessary for input is known as a voltage regulation curve of the this article, as to any multi -valve set. is obtained by connecting a milliammeter, adapting the eliminator almost filter, and the successive changes resistance voltmeter, and a variable resistance A schematic diagram showing a high a sine wave Fig. 3. The milliammeter should have a in waveform which result from passing as shown in various components of under r ohm and read from o to loo mA., (A.C. lighting mains) through the resistance in Fig. 5. At A a 50- whilst the voltmeter should read up to 30o volts and of the mains equipment is given is applied to the primary of not pass more than, say, io mA. at full scale reading. cycle alternating current ; increase in amplitude is The milliammeter, of course, reads the load due to the the transformer at B a slight (C) gives loo peaks resistance as well as that of the voltmeter. The resist- shown. Full -wave. rectification

50 PEAKS PER SECOND ' PER SECOND 50 PEAKS PER SECOND i 100 PEAKS V 0 O I i TO 2mfda FILTERTER RECEIVER RECTIFIER 4 mfds T O O o I O I i D E F A B C ;

D.C. Fig. 5. -A schematic on the Ondograph machine. output hich can be considered asea straight line in view fof the sucessfuletest per second, and the average D.C. component is shown as ance can have a minimum of 3,000 ohms. Fig. 4 is the present a horizontal line located so that the two shaded portions the voltage regulation curve obtained from the inserted after the 4 are equal in area. After the 4 mfd. condenser eliminator when the meters are out- as shown in Fig. 3. magnitude of ripple is less (D). The average D.C. mfd. condenser across the rectifier, is indicated by that the total H.T. current put available, as read by a moving coil, From Fig. 2 it will be seen (E) reduce the ripple is just over 26 mA. (using X. A further choke and condenser required for the receiver the filter (F) absorbs but the potential dividers in the considerably-likewise the rest of leaky grid detection), to a degree which it is con- this figure up to about 33 mA., with the fluctuating components eliminator bring of Ondograph test, to depict as be seen from Fig. 4 that a voltage sidered fair, in view the which load it will definition concerning the shortest is available. The values of the resistances satisfying Euclid's of about 265 between two points. (To be concluded.) required to reduce this potential to the requirements of path

THE USE OF HIGH ANODE VOLTAGES. few moments only, without anode voltage there are at if it is allowed to run, even fora Tj N the matter of the choice of keep the anode current down to a reason- conflicting influences. On the one hand, sufficient grid bias to Jl present two with able value. With this in mind, it will be realised that either knows very well that any valve will deal be switched one most cases the H.T. supply or the filament current should stronger signals without overloading, and will in for during the change the anode voltage used off before making any change in grid bias, yield a greater degree of amplification if another the valve is temporarily left with This is especially noticeable when from one voltage to is high than if it is low. bias at all. is in question, for the raising of the anode no grid must the output valve of In the earlier stages of the receiver similar precautions allows of a considerable increase in the volume usual, all valves voltage the loud speaker. be taken if, as is becoming more and more undistorted sound that can be obtained from anode voltage. The high -frequency to run up the high- tension volt- are operated with the same We are strongly tempted, then, have to deal with only a very small grid as a minimum, to the great improvement amplifiers, which re- age to some 200 volts swing, can be given an even greater grid bias than that results obtained. straight part of of the by observing nuired to operato them at the middle of the We are, however, discouraged from doing this biased almost down to this valve we buy, apart the curve; they can, in fact, be that upon the containing box, of every frequency amplifiers in the plate circuit there is inscribed in large print bottom bend. Low- from those of the L.S.5 class, is a transformer, may be similarly treated, or, if Maximum anode voltage 120 "; and, in addition, of which there -capacity the words, " the anode current is taken from the mains, a resistance often a definite statement to the effect that the makers that is actually there is life if this filter may be used to decrease the voltage will not guarantee their valves to have a reasonable at the same time that it fulfils the limit of voltage applied to the plate of the valve voltage is appreciably exceeded. Sometimes of checking any tendency to instability and 100 volts is the permitted its primary function is set even lower than this, oscillation. cases, mostly found among the valves of through L.P. no pre- maximum; in a few Resistance- coupled, low -frequency amplifiers require 150 volts is allowed. anode resistances from higher impedance, the cor- cautions, as they are protected by their In practice it is found in most cases that, provided that they are biased to the middle harm is done to the valve too high a current. Provided rect grid bias is used, no noticeable dynamic curve it is possible to take great rip to about 160 volts; in fact, this point of their of by using an anode voltage ; owing to the strict limitation by the " Power " tapping liberties with such valves voltage is that most usually supplied do not appear to be harmed by the continu- is most essential to re- plate current they of commercial battery eliminators. It of even 350 volts outside the resistance, even valves of low impedance such as are ous application the member, particularly with this may imply some 220 volts on the Ánoanode the loud speaker (the so-called " super- though L. used for operating valve itself. power " valves), that serious damage may be done to the valve B 23

www.americanradiohistory.com 792 Wflmlligge DECEMBER 12th, 1928. WoeIlol

No. 1.-The British Phototone System.

rrHE gramophone is a few years senior to the of the moving picture. During the past eighteen cinematograph. The former became popular months several nearly firms have sprung into being for the thirty years ago and the latter just over purpose of devoting their twenty. The idea energies exclusively to the of combining the one with the other supply of talking film equipment, has been obvious from and there are already' the onset, and one might well more than twelve theatres in this demand the reason for the country exhibiting delay in its accomplishment. talking films. ,The period of this advancement A common assumption was probably precisely that the problems coincides with the development of improved loud of synchronising the visual and acoustic reproduction speakers, were practically the moving coil type now being exclusively insurmountable. This, definitely, was used in the not the reason several systems. The wireless enthusiast for the delay. Quite simple mechanical is, therefore, the most devices are now severe critic of the talking film, used to achieve synchronising, while the and its close link with amplifier process by which the speech and loud speaker design is light recorded on the has given rise to the inclusion of articles edge of the film had long been on the subject known, yet still the from time to time in the pages of this journal. talking film did not take its place in the cinema. Those who have followed the growth of the talking How Film and Record are Synchronised. film are well aware of the difficulty that has delayed its Turning our attention now in particular to the British introduction. It is not the problem of synchronising Phototone system, but rather that we are chiefly interested in the pro- speech and musical reproduction has cess of synchronising picture and loud speaker been far too defective to be or, going associated with the reality back to the source, the film and the gramophone record. As everyone knows, the film is driven through the projector by a sprocket wheel, the small pins of which engage in the perforated holes running along the two edges of the film. This sprocket drive must be positively coupled through suitable gearing with the gramo- phone turntable, the relationship be- tween the record and film being the same during recording as when repro- ducing. It is surprising that synchronis- ing is so simple, it being merely neces- sary to introduce such mechanical requirements as will ensure smooth running. To better appreciate the detailed re- quirements the reader might set himself the problem of running film and record in step. Nothing could be easier than that of marking the gramophone record Two turntables are employed in order to give continuous speech reproduction at a particular point on its first ' groove throughout the progress of the film. The turntables are started spontaneously by means of small metal contacts attached to the edge of the film. The drive and setting a certain marked portion of of the turntables is coupled to the mechanism which propels the film. the film in the shutter. Both would B 24

4

www.americanradiohistory.com 74.E 1928. Nrzc7o,r DECEMBER 12th, WUCIl

Talking Films. - away together, and being driven from a common start as source of motion would continue exactly in step just they did during recording. Thus, for a few minutes the arrangement would be satisfactory. Changing Records. Provision must be made, however, for changing over record to another, without delay, as the film from one be progresses. This change -over can conveniently made either during a display of caption or at a time of silence. A feature of the Phototone system momentary contact is that a record is started by a small electrical is a small attached to the film. Clipped on to the film silver foil for contacting, and on passing a given piece of the point the record is thrown into rotation beneath

contact on the film contacts is amplified and energises a relay e hichlcloses of the magnetic clutch. a wide trical pick -up with the first groove on the record arrow marks groove pitch is allowed, . and an indicating starting point. Should record and film inadvertently the about the used for driving out of step, the pick -up arm is rotated The geared cross shaft run until the d vertical sIlindles centre spindle so as to either overtake or fall back record accompanies the movement with the slyer con- the passage of the needle spontaneously. Associated The correction is made without inter- amplifier, in the anode cir- of the film. tact is a single stage valve A second flywheel is also in synchronous fitted with a double set of con- ruption. cuit of which is a relay alongside the first, and is likewise arranged to a local circuit through a battery rotation an tacts. One set closes give immediate rotation to a second record when on the relay by which means to the and an additional winding impulse is received from the tiny contact attached -up of the armature causes it to hold. means successive a brief pulling clutch of side of the running film. By this The other pair of contacts energise a magnetic into operation, changing over described in association records are brought similar form to that recently from one turntable to the other. receiver. This clutch sets the alternately upon with the wireless picture Thus the quality of reproduction is dependent the gramophone record in rotation. amplifying equip- turntable carrying clutch the merits of the recording and might be thought that the duty of the magnetic arrangement of the loud It it gives a very ment, and the type and is to slip, but actually when energised speakers. Little is left for de- positive drive. scription in this connection, as To overcome the inertia present the Phototone system is fortunate when setting the record in rotation in that it adopts in its entirety a heavy cast iron flywheel is em- the public address equipment of

ployed running at the correct speed Siemens Schuckert. . This equip- by being directly coupled to the ment has already been referred to, sprocket wheel of th" projector. its chief distinction being the Flywheel and turntable have, of Blatthaller loud speaker which it course, concentric shafts, and the uses. Instead of a pair of mag- magnetic clutch couples them to- netic poles as are provided with the gether. As instantaneous starting annular ring form of moving coil A the record is impossible, a spiral loud speaker the Blatthaller is corn- spring device is interposed between posed of a grid consisting of a large the clutch and turntable shaft. Re- number of alternate poles interlaced sistance offered by the turntable on with a ribbon conductor carrying starting is temporarily taken up by the speech currents. To this con- this spring, but this does not cause ductor is attached the diaphragm loss of synchronisation, as it later which, moving as an entirety, gives releases to the original setting while Flywheel, turntable and magnetic clutch, a considerable air displacement, together with the adj usting mechanism, used the rotating. to bring the pick -up to the correct position and possesses in a large measure To facilitate engaging the elec- on the recor B 25

www.americanradiohistory.com ? "4444"4444A

794 WAweIleog. DL'G'EMtfAtc zath, 1028. WUF's llC'' calking Films. - theoretical ideals desirable in loud speaker diaphragms. A battery of these loud speakers is arranged behind the screen, the volume out- put being adjusted to suit the acoustic conditions of the hall. Power for am- plifiers and field excitation is derived from a direct - coupled motor generator. The non -directional pro- perties of the loud speaker are in its favour, for they give a natural- ness of effect when repro- ducing a full orchestra, while not revealing the pre- cise point from which the voice is emitted when giving Battery of Siemens Schuckert speech to screen (Blatthaller) loud speakers as placed behind the screen in the artist. British Phototone system. the

LET "J1 ERS TO THE EDITOR. The Editor does not hold himself responsible for the opinions of his correspondents. Correspondence should be addressed to the Editor, "Tae Wireless World," D.irset House Tudor 3treat, E.C.4, and must be acaimraaied bi the writer's name and address. STANDARDISATION-SCREEN -GRID VALVES. LOUD SPEAKER `ATTACK." S'ir; I have recently had cause to notice the different methods Sir, -It is a curious fact being adopted by that a discussion departs sooner valve manufacturers in the connections to or later from matters of fact and becomes screen -gri d valves. matters of opinion. The letter of " Curious " in your issue Most makers now appear have of November 7th is a to adopted the vertical type case in point. Your blue pencil forbids us dealing of valve with the terminal on the top, but there is apparently with this letter in detail, but we crave space to query one sentence, which no agreement between them as to the method of connecting reads as fDllows :- the various electrodes. For instance, the Mollard valve has the In the case of the connection Reed drive low frequency transients have for the anode brought out to the extra terminal, no chance at all because there is no whilst the usual anode bass." We take it that the pin is utilised for the screen connection. writer includes balanced armature movements. I believe this also applies to the Osram and Ediswan makes. Perhaps he would therefore amplify his bold statement by replying to the In the B.T.H. valve, however, the control grid is brought out following queries :- to the -top terminal, and the screen grid connection is by means (a) Has he tested every movement that is commercially of the usual " grid " pin on the base of the valve. available? I do not know what are the factors governing the arrange- (b) What apparatus he used to produce, say, half a dozen ment of these connections, but I do think (unless there is pure notes in they lower definite reason register two octaves below middle C, for this variation) that it should be possible for and what was the value of those notes? the various makers to adopt some standard method. (c) What, was the connecting Some of your link between the pure note readers may care to indicate their views, or apparatus and the input side of the unit? perhaps the makers themselves would like to set cut their (d) What type of apparatus was fed by the output side of reasons for the various methods in use. S'. WEBS TER. the unit? Enfield, Middlesex. As we are 'curious on all these points perhaps we may be permitted to sign ourselves " CURIOUS SECUNDUS." London, Sir, --Mr. Rowett's W.C.2. letter on the subject of standardisation November 7th, 1928. raises an interesting point with regard to screen -grid valves. [ have always considered the double -ended type to be a dis- 7inct advance on the ordinary single-ended valve; making, as It does, for maximum separation of the electrode leads and DIODE RECTIFICATION. great convenience in external screening. I was very sorry, Sir, -I have been very interested in the recent correspond- therefore, when British valve manufacturers went back to the ence on the diode rectifier. single -ended type (with anode fixed to the top), thus copy- Although I would consider this detector justified on the ing the Americans. I am quite aware that the latter type is score of quality alone, there more efficient than is one other point which has not the older double -ended type, but I do not been stressed, and should appeal to mains users. imagine this extra efficiency has any inherent connection with the The fact that the detector shape of the valve. valve does not take an H.T. supply at once removes a possible source of hum and motor -boating. Let us by all means have standardisation where it does not I changed from anode bend to this arrangement about a year interfere with efficiency and convenience, but I would strongly ago, and find two L.F. condemn any attempt stages are ample if there is some at standardisation which might act as a preceding H.F. magnification. W. R. PARKINSON. check on progress. ROGER NORTH. Streetlyi Buckingham Staffs. Gate, S.W.I. November 15th, 1928.

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www.americanradiohistory.com DECEMBER 12th, 1928. WApisD®go 795 WonfIld

1I , l 11ii1i1«i11111 h ; '111,11l ÌÌ00 ! n CF2RE,"NTmI TOPICI' Events of the Week in Brief Review. MODERN INSTITUTIONS. FIRST COME, FIRST SERVED. TRANSATLANTIC WIRELESS HISTORY. to be a To -day (Wednesday) marks the twenty - In two East Sussex Poor Law insti- Christmas, 1928, promises have super- wireless. Those who seventh anniversary of Senatore Mar - tutions wireless installations record season for seded gramophones. make their radio purchases early have coni's reception of the first Transatlantic the best choice. Verb. sap. wireless signal. 0000 0000 000o SHORT WAVES FROM SWEDEN. NEXT? PROVERBS FOR PRESENT CHOOSERS. EMPIRE TELEPHONE SERVICE At irregular intervals the Swedish hand is worth three ties In view of the success of the Trans- high -power station at Motala now broad- A valve in the Post wavelengths, or four pairs of socks. atlantic telephone service, the casts simultaneously on two to be considering viz., and 99 metres. A soft answer turneth away wrath, but Office is understood 1,363 services with a loud speaker goeth one better. the opening of similar 0000 0000 different parts of the Empire. It is possible that preliminary tests may shortly WIRELESS- CABLES MERGER. WIRELESS FOR P.O. STANDBY be made with Australia. It is considered that the position of A Post Office wireless station is to be chairman of the new wireless- cables erected at Fleetwood for use when the merger company may be offered to Sir cables to Ireland and the Isle of Man are Basil Blackett, a former Controller of out of action. CHRISTMAS HOLIDAYS. Finance at the Treasury. 0000 0000 POWERFUL DUTCH COLONIAL STATION. GERMAN HIGH POWER CALIBRATION Earlier Publishing Dates. SIGNALS. is considering The Dutch Parliament benefit of installation of a short -wave Calibration signals, for the a Bill for the OW ING to the Christmas Holidays German broadcasting stations, are station in the East Indies with a power the The station would pro- " The Wireless World," dated regularly transmitted on the 11th and 12th of 600 kilowatts. day of each month throughout the year vide five channels for simultaneous tele- December Igth will be on sale with Europe be- by the high -power Koenigswusterhausen graphic communication on the previous day, and the station. The broadcasts are carried out sides two or three telephone circuits. issue dated December 26th, on between 5 and 7.15 a.m., G.M.T., but 0000 should one of the test days fall on a MARCONI PIONEERS. Monday December 24th. Sunday the experiment is carried out on Dr. J. A. Fleming, F.R.S., was among the following day. the guests at a dinner given by Senatore Times of transmissions are as follows :- Marconi on November 29th to those who AUSTRALIAN DUTIES ON WIRELESS MORSE had been connected with the Marconi SETS. G.M.T. LETTERS. WAVELENGTHS. companies for twenty -five or more years. Australian radio manufacturers are 1st day. 2nd day. on im- 05.00 05.05 A 1,440 2,750 Dr. Fleming has been in association with petitioning for increased duties 03.15 05.'20 C 1,100 1,065 the companies almost from their incep- ported wireless sets. The existing duties 05.30 05.35 1c 1,000 "1,785 05.45 05.50 1,050 1,650 guest was Colonel H. are : British preferential, 35 per cent. ad. tion. Another 00.00 06.05 li 1,000 1,565 ; and Jameson- Davis, founder of the original valorem; intermediate, 50 per cent. 06.15 06.20 O 1100 1,525 Wireless Telegraph and Signal Company general, 55 per cent. No objection is 116.30 06.35 P 800 1,475 on 00.43 06.50 X 750 1,401) in 1897. raised to this scale of duties com- 1,360 0000 on 07.00 07.03 Y 720 ponents, but an increase is asked for 1)7.15 07.20 'L 700 1,140 COMPULSORY WIRELESS ON SHIPS. completed sets. 0000 of disclosures made during 0 0 0 0 As a result' WIRELESS LEAGUE. the New York enquiry into the loss of FOREIGN BUYERS OF MARCONI THE the Merchant Navy Re- SHARES. At the annual general meeting of the the Vestris, of shares in form Society has sent a manifesto to Extensive foreign buying Wireless League held at the Royal Auto- urging that compulsory the Marconi International Marine Com- mobile Club an account was given by the the Government led the direc- Stanley, of the wireless on all ships should be discussed munication Co., Ltd., has chairman. Sir Arthur Conference on Safety tors to convene an extraordinary meeting League's activities during the past year. at the International Friday next, includes the insurance of of Life at Sea, which will meet in Lon- of the shareholders on Membership December 14th, to consider whether the wireless sets and accessories, free don next April. legal advice on all Vestris enquiry showed that company's Articles of Association shall technical help, and The company matters. Through its branches the small steamer " Montoso " might be altered to provide that the wireless the wreck in shall continue under British control and the League has done useful work in pre- have reached the scene of wireless sets, if had been equipped that not more than 25 per cent. cf its senting hospitals with free time to save lives it raised by concerts, whist with wireless. issued shares shall be in foreign hands. the funds being B 27

www.americanradiohistory.com ,. . . ,.1- - - '`"', ^ 796 Vpasoo 'MAO DECEMBER 12th, 1928. drives, and the like ; whilst blind persons to the output line amplifier. have Three not yet been brought into regular opera been helped by receiving at a re- water -cooled valves connected in parallel tion. duced rate copies of the Radio Times are used in the power amplifier circuit. Hach.) Schaerbeek, a privately oia-ned - printed in Braille. The offices of the The aerial will be supported on two League have recently station erected some few months ago, has been removed to 300ft. towers about 600ft. apart. decided to increase 19, Berkeley Street, London, W.1, its power from 100 and 000o watts to 5 kilowatts. full particulars of membership may be 0000 had from the secretary. P'.C.J.J.'s NEW SCHEDULE. ooòo The famous Philips station at Hilver- WIRELESS AT WESTMINSTER. CZECHO- SLOVAKIA'S NEW BROAD- sum, working on 30.2 metres (telephony), (From oar Parliamentary CASTING STATION. Correspondent.) has opened a new campaign with the Broadcasting The new Czecho -Slovakian broadcasting object of being_ and the General Election. heard in places as far Broadcasting in relation station at Bratislava, the transmitter of apart as British India and Australia. to politics The came up for consideration in the House which is illustrated on page 806 of this following weekly schedule (G.M.T.) is issue, of Commons last week when Sir Nicholas will be the largest of five stations now being observed :- Grattan- comprising that country's Doyle asked the Postmaster - broadcasting THURSDAY : From chain. The transmitter, 1800 -2000 for British India, General whether during the period of the a product of the Europe and South Africa. General Election British Marconi Company, is constructed From 2300 -0 for Spain (in Spanish.) it was proposed to allow FRIDAY : From the on the unit system, each 0 -0100 for Brazil (in Portuguese). broadcasting of political speeches. circuit being From 0100-0300 for the South American Viscount Wolmer replied carefully screened from its Republics (in that he could neighbour. Spanish). not yet say political Two rectifying panels are employed, From 1800 -21100 for Europe. that speeches, if any, each SATURDAY : From 0-0100 for the Dutch West Indies. would be broadcast by the B.B.C. during containing three water-cooled valves From 0100-0400 which are for Central American the General Election. fed by three single -phase and Antillian Republics, as well as for 0000 transformers, and the rectified unit sup- the Br,tish and French Colonies in America (in English, Spanish and Licences per plies the intermediate and power ampli- French). Thousand of Population. fiers with direct current, at between 8,500 From 0400-0600 for Australia and New In reply to a question regarding wire- and 10,000 volts. The drive unit uses Zealand (in English). less receiving licences in Wales, the Post - two type D.E. T.1 valves, the anode o000 master- General, Sir William Mitchell - voltage being provided by a H.T. D.C. BELGIAN BROADCASTING. Thomson, stated that the total number motor generator of licences in force on October in taking current from an In a few weeks Brussels will be in the 31st accumulator battery, which is also used possession the whole of Wales was about 80,600, of a high -power transmitter which was equivalent to light the filaments. The modulator is from which many readers to a rate of 36.5 resistance- capacity may already per thousand of population. The corre- coupled to the sub - have heard tests at irregular modulator, and intervals. sponding rate for England was 62.8, for the sub -modulator is On one or two evenings it has broadcast arranged for resistance capacity coupling Scotland 57.3, and for Northern Ireland the Radio Belgique programmes, hut has 21.9.

WIRELESS IN WAR OF THE FUTURE. The Work of the Territorial Signals. The heading of this note may seem was designed by the 47th (2nd London) knowledge sensational, and the 47th (2nd London) Divisional or still rank as beginners. Divisional Signals, who welcome any Headquarters are at Fulham Signals T.A sincerely trusts new members to the House, that it is unlikely unit interested in 50 yards from Putney- Bridge Station of realisation, but, wireless, whether they have any expert on nevertheless, in the present state of world the Underground. politics, it is an eventuality which must be reckoned with. That is the reason why the Territorial Signals are trying to assist in spare time in the solution of the interesting problems attendant on fitting wireless telephony into vehicles, the design and use of small portable wire- less stations for communication between rapidly moving bodies of troops, etc. Training takes the form of making the force efficient in the use of the various forms of wireless with which the unit is equipped among other means of signalling, but in addition opportunities are given of looking into the future. The authorities controlling army wireless research have adopted the principle of trying new designs " on the dog," namely, Territorial Signals. New de- signs, as they are produced, can only be tried out adequately by the man who is going to use them in practice under the actual conditions which prevail in war. This is not always easy to stage at short notice, and from time to time Terri- torials are asked to spend an afternoon 'or a week -end in trials of new designs and to report as " users." This gives glimpses into the future and is very interesting. The illustration shows a type of port- A TERRI'' ORIAL FIELD SET, able telephony and telegraphy set which for telephony and telegraphy; designed by the 47111 (2nd London) Divisional Signals. B 28

www.americanradiohistory.com 4. t41:.y,L'.- . ..4i

DECEMBER 12th, 1928. WIlmheig 797 Woi-Dl lo R 4oM3RQ

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BARCELONA (Radio Barcelona), Call EAJI (844.8 Snecwittchen (Erdlen) ; Reading from The Princess metres) ; 1.5 kW. -8.10, Sextet Selections : Two - and the Swineherd (Andersen) ; Andersen Fairy Tale Step Ecos de E palta (Iberito) ; Selection from Lucia Suite Op. 60 ( Kampf) ; Reading front The Bremen di Lammermoor (Donizetti) ; Waltz, A la française Town Band (Brentano ); Symphonic Burlesque, The (Gedalge -Guinaud), De Huelva -fandanguillo (Romero), Bremen Town Band (Reifner). 4.30, Programme from Benamor (Luna). 8.30, Fortnightly Report of the Königswusterhausen. 5.0, Request Prcgramnte. Institute of`t-lygiene followed by Elementary French 6.0, 'Talk: A Visit to the Hamburg Observatory. Lesson. 9.0, Chimes and Weather Report. 9.5, 6.55, Weather Report. 7.0, "The House Ball." Exchange Quotations and News. 9.10, Orchestral 9.30, Weather Report, News, Sports Notes and Pro- Music. Selections : March, Pomp and Circumstance (Elgar) ; gramme Announcements. 9.45 (approx.), Dance Selection from Madame Pompadour (Fall) ; Baba era 10.50, North Sea and Baltic Weather Report. clásica (Raurich) ; Falling Petals- Boston (Soler) ; 5 kW. Sevilla )Albéniz) ; Overture to Zampa (Herold). HILVERSUM (1,071 metres) ; -.9.40 to 9.55 10.0, Programme relayed fron Madrid, EAJ 7. SATURDAY, DECEMBER 15th. a.m., Time fig tai and The Daily Service. 11.40 a.m., Police Annoncements. 11.55 a.m., Trio Concert. Programme 1.40, Concert from the Tuschinski Theatre, Amster- BERGEN (370.4 metres) ; 1.5 kW. -5.30, dam. 3.40, Italian Lesson. 4.40, French Lesson. for Children. 6.0, Talk for Girls. 7.0, Orchestral to Greenwich All Times are reduced 5.40, Concert of Waltzes and Marches : March, El Concert. Topical Talk. 8.0, " The Soul of a 7.50, Capitan (Sousa) ; Waltz, Wiener Blut (Job. Strauss) ; negro described in West- African "I ales of Adventure," Mean Time and are p.m. except March, The Gladiator's Farewell ( Blankenburg) ; Waltz, Mr. -Nielsen. 8.30, Pianoforte and by Schroder Moudnacht auf der Alster (Fetras) ; March, Panache Violin : Sonata in A Major Op. 100 (Brahms). Recital where otherwise stated. rouge (Grit) ; Waltz, SJirée d'été (W"aldteufel) ; F Report, Sonata in Minor (Francoeur). 9.0, Weather March, Old Comrades ('t eike). 6.25, German Lesson. News and Time Signal. 9.15, Dance Music. 11.0 7.25, Police Announcements. 7.45, Concert and Talk (approx.), Close Down. BRUSSELS (508.5 metres) ; 1.5 kW. -5.0, Orchestral arranged by the Workers' Radio Society. 11.15 Concert from the ArmenonVille Tea Rooms. 6.0, (approx.), Claw Down. BERLIN (Königswusterhausen) (1,250 metres) ; 40 Intermediate kW. -3.30, Programme from Hamburg. 4.30, Herr Elementary English Lesson. 6.25, English Lesson. 6.45, Pianoforte Recital. 7.0, HUIZEN (340.9 metres) ; 4 kW.-Transmits ou 1,852 Potzel, Talk : The Inland Revenue-Anecdotes Grave Gramophone Selections of Dance Music. 7.30, " Radio - metres from 5.40 p.tn.- 12.10, Concert of Trio Music. and Gay. 5.0, Prof. Woldt, A Discussion with In- 2.40, Programme for Children. 5.0, Gramophone dustrial Workers. 5.30, Advanced Spanish Lesson. Chronique." 8.0, Concert from the Liége Conserva- : Alpaertz) ; Spanish Selections. 6.10, Talk by M. Gerisch. 6.30, Catholic, 5.55, Talk by Dr. J. Nadler. 7.0, " Agricultural " toire Symphonic Suite (Fier. Symphony (Lalo) ; han de Stora Skogarna (Lind- Bulletin. 6.40, English Lesson. 7.10, Lesson in Programme : Choral Selections, (a) Heimat (Wiesner) berg) ; Vi ^lin and Orchestral Selection, Basque Dressmaking. 8.0, Concert of Orchestral and Vocal (b) East-Mark Peasant Song (Buck), (c) Wer bat Music, M. Fantasia ( Pierné), Symphonic Poem, Ballata delle with Recitations by Boezer. dich, du schöner Wald (Mendelssohn). Talk : Peasant Choral Selections, (a) Im schön- gnomidi (Respighi) : Topical Talk in the Interval, Rights and Morals, KALUNDBORG ; 7 Programme ich den followed by News, Esperanto Report and Orchestral (1,153 metres) kW.- sten Wiesengrunde (Wagner), (b) Wenn Close also for Copenhagen (337 metres).- --8.80 a.m., Morning Wandrer frage (Hegar), (c) Wem Gott will rechte Concert from the Palace Hotel. 11.0 (approx.), Down. Gymnastics. 10.0 a.m., Weather Report. 10.15 Gunst erweisen (Mendelssohn), (d) Das Wandern ist a.m., Educational Talk. 11.0 a.m., Chimes from the des Müllers Lust (Zöllner), (e) Nun ade, du mein BUDAPEST (556.6 metres) ; 20 kW. -4.10, Talk by Town Hall. 11.5 a.m., Orchestral Concert from lieb Heimatland (Kirchl). 8.10 (approx.), Programme Song Recital Wivel's Restaurant. 2.0, Programme for Children. from koloman Rossahegyi. 5.20, Hungarian Voxhal's. by Frau Emma Kmnlossy. 6.20, Relay from the Opera 2.30, Concert of Orchestral Selections. In the Interval House, followed by Weather Report and News at Recitations by Hans Dynesen. 4.50, Talk by Mr. N. BERLIN (Voxhaus) (484 metres) ; 4 kW. -9.10 a.m., 9.30, (approx.), and Recital of Sings with Ac -ompani- Esbjerg. 5.20. Mr. F. C. Becker, Talk : Central Market Prices. 9.15 a.m., Weather Report, News ment on Old Hungarian Wind Instruments. 10.15, Heating. 5.50, Weather Report. 6.0, News and and Time Signal. 10.0 a.m., I'r gramme of Gramo- Band Music relayed from the Hotel Hungaria. Exchange Quotations. 6.15, Time Signal. 6.30 phone Records. 10.30 a.m., Exchange Quotations. Mr. leer Gudme, Talk : Modern American Authors. 11.55 a.m., Time Signal. 12.30, Weather Report and CRACOW (566 metres) ; 1.5 kW. -4.10, Mr. M. Jed - 7.0, Chimes from the Town Hall. 7.5, Reading. 7.80, News. of Gramophone Records. Selection of New Work Songs, followed 1.0, Programme licki, Talk : The Monarchist Movement in France at Danish by 2.0, Exchange Quotations, Agricultural Report and the Present Time. 4.35, Programme front Warsaw. News. 8.15, Violin Recital by Harald Andersen: 'lime. Signal. 2.30, Talk by Dr. Rudolf Wegner. 5.0, Prcgramtne for Children. 6.0, Miscellaneous Concert Polonaise, Op. 4 (Wieniawsky) ; Caprice 3.0, Sports Review by Dr. Hans Bollmann. 3.30, Items and News. 6.25, English Reading by Mr. J. viennois (Kreisler) ; Scherzo- Tarantella Op. 16 Richard Wilde, Talk and Reading : Gutzkow, on the Stanislawski. 6.55, Time Signal. 7.0, Agricultural (Wieniawsky) ; Humoresque (Dv.,rak, arr. Kreisler) ; Recital for Two 50th at.n.versary of his Death. 4.0, Report. 7.5. Mr. J. Regula, Talk : Review of Foreign Hungarian Air, Op. 22 (Ernst). 8.45, Orchestral Pianos : Fantasia and Fugue in G Minor for Organ, Politics during the past week. 7.30, Programme from Concert : March, Advance ! (Totit) ; Selection from Two Pianos (Singer) ; Duettino conzertano (Mozart) ; Warsaw. 9.0, Programme from Warsaw. 9.30. Der Bettelstudent (Millöcker) ; Caecilie Waltz (Lum- Gavotte (Pirani). 4.30, Tea Concert from the Hotel Concert from a Restaurant. 10.30 (approx.), Close bye) Saeterjentens Söndag (Ole Bull) ; Toreador Kaiserhof, followed by Advertising Notes. 5.40, Down. et Andalouse (Rubinstein) ; Strofe for Strings, Advertising Talk by Max Hansen. 8.0, Georg Haus- Organ and Pianoforte (Bartholdy) ; Böljeby -Vals dorf, Talk : Modern Art. 6.30, Talk. 7.0, " Uriei DUBLIN, Call 2RN (319.1 metres) ; 1.5 leW'. -1.30. (Peterson- Berger) ; Yelka March (Reesen). 9.45, Acosta " -Play, with Introductory Talk by Gerhart Weather Report and Gramophone Selections 7.20, Dance Music by the Industry Restaurant Orchestra. l'ohl, on the Occasion of the Fiftieth Anniversary of News. 7.30, Health Talk by Mrs. A. Russe M.B. 11.0, Chimes from the Town Hall. 11.15 ( approx.), the death of Karl Gutzkow, followed by Weather 7.45, Irish Lesson by Seamus O'Duirinne. 8.0 to Close Down. Report, News, Time Signal and Sports Notes. 9.30, 10.30, Symphony Concert by the Station Symphony Dancing Instruction by Reinhold Sommer, followed Orchestra and the Phibsboro' Choir. 10.30, News KATTOWITZ (422 metres) ; 10 kW -2.45, Financial by Dance Music. 11.30 (approx.), Close Down. and Weather.Report. 10.45 (approx.), Close Down. Report. 3.0, Gramophone Selections. 4.10, Music Lesson by Prof. F. Sachse. 4.35, Children's Letter Box. Programme for Children. 6.0, Announce- BRESLAU (322.6 metres) ; 4 kW. -2.0, Review of FRANKFURT (428.6 metres) ; 4 kW. -2.5, Pro- 5.0, Books by Dr. Ernst Boehlich. 3.0, Orchestral Concert. gramme for Children. 3.35, Vocal and Orchestral ments and News. 620, Talk by Mr. K. Zienkiewicz. 4.30, Programme relayed from Königswasterhausen. Concert : Overture to Das Nachtlager in Granada 6.56, Time Signal and Agricultural Report. 7.5, : of Film Review by Herr M. Lippmann. 5.20, (Kreutzer) ; Selection from Euryanthe (Weber); Mr. K. Rutkowski, Talk Impressions a Journey 5.0, Programme relayed from Programme in Commemoration of Zamenhop, the Song ; Selection from Undine (Lortzing), Overture to to Constantinople. 7.30, ; ; Weather Report and News. 9.30, originator of Esperanto. 5.45, Travel Talk : Siberia Des Falkners Braut ( Marsebner) Song Selection Warsaw. 9.0, and Mongolia. 6.20, Shorthand Lesson. 6.50 Read- from Tannhäuser (Wagner) ; In the Interval -Wire- Dance Music. ing in English by Douglas Yates, M.A. 7.15, Variety less News and Announcements. 5.10, Reading by : ; 7 kW. Weather Programme : Orchestral Selection from Hansel and O. W. Studtmann. 6.30, Talk Postal Regulations for KAUNAS (2,000 metres) -5.0, News. Agricultural Report Gretel (Humperdinck) ; Tenor Songs ; Five German Christmas. 5.45, " The Letter Box." 6.15, Esperanto Report and 5.15, 5.45 Concert. Talk on Folk Songs ; Orchestral Selection, Silesian Songs Lesson by W.. Wischhoff. 6.45, Prof. Hülsen, Talk: Announcements. 6.80, 7.0 Dzuku Recital. 8.0, Talk by (ïiilse) ; Tenor Songs ; Songs ; Orchestral Selection ; The Jewish Cemetery in the Börueplatz as a Memorial Neurasthenia. 7.30, Songs (a) Ein Schäfermädchen weidete (Seidler- to Culture and Art. - 7.15, Variety Concert with Ernst Mr. K. Berulis. 8.15, Dzuku Recital (continued). Winkler), (b) Du, du liegst mir im Herzen, (c) Die Arnold, Vienna, in some of his own Songs, followed by metres) ; 35 kW. -5.15, Orchestral Auserwählte ; Orchestral Selection, German Dance Dance Music relayed from Voxhaus. 11.30 (approx.), LAHTI (1,522.8 (Schubert). 9.0, News. 9.30, Dance Music. 11.0 Close Down. Selections : Kleiner Wienermarsch (Kreisler) Synco- (approx.), Close Dosen. pation (Kreisler) ; Do -Re -La (Lehár) ; Intermezzo HAMBURG, Call HA (in Morse) (394.7 metres) ; 4 (Nevin) ; Selection for Two Guitars (Harlick). 5.40, : Couplets, Talk BRÜNN (441.2 metres) ; 2.5 kW. -4.30, Music Talk k \V. -9.15 a.m., News. 10.0 a.m., Programme of Talk. 6.0, Wireless Programme by Dr. Vetter]. 4.45, German Programme, Ness's and Gramophone Records. 11.10 a.m., Weather Report. and Dramatic Selections. 7.45, News in Finnish and Swedish and Close Down. Concert : Mignon (Thomas) ; Robert le Diable 11.15 a.m., Exchange Quotations. 11.30 a.m., Concert (Meyerbeer). 5.15, Weekly Report for Journalists. relayed from Hanover (207 metres). In the Interval at News. Exchange LANGENBERG (468.8 metres) ; 20 kW.- Programme 8.0, Dr. Ziska, Talk : Czech History. 6.15, Talk on 11.55 a.m., Time Signal. 12.10, 1.40, Winter Sports by Mr. Koch. 6,30, Programme, re- Quotations. 3.0, Illustrated Music Talk by Wilh. also for Aix -la- Chapelle (400 metres), Cologne (283 layed from Prague. 9.0, Programme relayed from Heinitz. 3.30, Concert of Musical Fairy Tales metres), and Munster (250 metres). -9.35 a.m., Labour Prague. Reading front Sneewittchen (Grimm); Suite from Exchange Report. 10.10 a.m., Talks : The Choice B 29

www.americanradiohistory.com wirrwimk. 79'8 Vflpasom MAO DECEMBER 12th, 1928. Programmes fro m Abroad. - relayed front New York. 4.0 a.m., Time Signal and of Careers. 11.10 a.m., Gramophone Selections. Saturday, December 15th. Dance Music from the Hotel Van Curler. 6.0 a.m. 12.5, Orchestral Concert. 1.30, Hints for the House- (approx.), Close Down. wife. 2.40, Herr P. Brills, Wireless Talk : The Con- denser in Direct and Alternating Current Circuits. STAMBOUL 3.0, Talk for Women All Times are reduced to (1,200 metres) ; 5 kW -3.30, Concert. by Hertha Maria Funck. 3.30, Greenwich 4.30, Market Report. Concert Dr. Wilhelm Leyhausen, reads from " Lettres 5.15, of Turkish Music. de mon Mean Time and are p.m. 7.30, Weather Report and Time Signal. 7.40, Orches- moulin " (Daudet). 4.0, Fegeler- Felkendorf, Talk : except tral Concert : Overture No. 3 from Time, Modes, and Men. 4,20, English Lesson Leonora (Beet- by hoven) ; Violin ; Prof. F. Hase. where otherwise stated. Solo Songs ; Suite front L'Arlésienne 4.45, Concert by Lute and Mandoline (Bizet). 9.0, News and Close Down. Orchestra : Mandoline Selections, (a) Er weicht der Sonne nicht (Blankenburg) ; (b) In a Persian Market STUTTGART 4 (Ketelbey), (c) Overture in B Minor (Wölki) ; Zither (379.7 metres) kW.-3.35, Pro- Orchestral Concert, of Light Muec : Comedy Overture Solos, (a) Herzliches Gedenken (Grünwald), (b) Fan- gramme relayed from Frankfurt. 5.0, Time Signal and (Keler Bela) ; La Serenata (Tosti) ; Tzigane Song Weather Report. tasia on Strauss Waltzes (Kolmaneck) ; Mandoline 5.15, Dr. Kümmerten, Talk : Army (Renée) ; Selection from A Waltz Dream (Oscar Straus); Pensions. Selections, (a) Wolgaklänge (Ritter), (b) An 5.45, Major Carl Lauge, Talk : Danzig and der Amoureuse (Gillet) ; Mon rêve ( Waldteufel) ; Weser (Pressel), (c) Lustige Finken (Ritter). Selec- German Culture. 8.15, Legal Talk by Herr L. Leib - 5.30, tion (Mouton) ; Viennese Waltz (Heiber) ; and Alaine fried. 8.45, Friedrich Felger, Talk : Dr. Hans Zbinden, Talk : The International Problems Melody (Schroder) Waltz Potpourri Literature of the of America. Herr P. from Die ges- Great War. 7.15, Time Signal and Sports Notes. 6.15, Leistenschneider, Talk : chiedene Frau (Fall). 8.0, 'Cello Recital by M. Guil- For Workers : Insurance 7.30, Concert : " On the beautiful blue Danube " ; against Accident in the laume Hesse. 8.30, Weather Report and News. Mining Industry. Overture to The Gipsy Baron (Strauss) ; Poets from 6.40, Prof. Leyen, Talk : Fairy 8.45, Topical Talk. 9.0, Cabaret Programme. 10.0, Austria (Fortner) ; Tales of World Literature. 7.0, Variety Programme. Dance Dorfschwalben aus Osterreich Music from the Grand Hotel. 11,0 ; 9.30 (approx.), News, Sports Notes, Business (approx.), (Strauss) Der Ländler (Bartsch) ; Grüss mir mein Announce- Close Down. Wien ments, Orchestral Selections and (Kalman) ; Das warn Zeiten (Kalman) ; Pizz Dance Music. 12.0 Polka Midnight (approx.), Close Down. (Strauss) ; Wiener Burgeri (Ziehrer) ; Modern PARIS (Ecole Supérieure), Call FPTT (458 metres) ; Austrian Poetry (Fortner) ; Wien, du Stadt meiner 0.5 kW. -4.15, Concert : Selection from I Pagliacci Träume (Scezyinsky) ; Selections (Ernst Arnold), LEIPZIG (385.8 metres) ; 4 kW.-3.30, Mandoline (Leoncavallo) ; Berceuse (d'Ambrosio), Jubel Over- a) Das war am alten Glacis, (b) Das Lied von der Concert : March, Mandolinismo (Colette) Chimes ture (Weber) ; Canzonetta (Filipucci). 6.30, " Radio merin, (c) Das Wienerlied ; Waltz, Künstlerleben (Vicari) ; Under the Cyclamens-Waltz (Debiassi) ; Journal de France." 8.0, Talk by M. G. Geville. 8.15, (Strauss) ; " The Farewell Supper " : Comedy (Schnitz - Invocation (Patti) ; Popular Potpourri ( Vicari) ; Scientific Talk. 8.30, Concert arranged by the Re- 1er) The Blue Danube (Strauss) ; Viennese Humour Serenade, Mandolinata (Colette) ; Tango, Spring naissance Française and Dance Music from the Coliseum (Fortner) Caprice viennois ( Kreisler) ; Auf der (Vicari) ; Selection from Faust (Gounod) ; Intermezzo, de Paris. 12.0 (Midnight) (approx.), Close Down. Lehmgruben, da steht a alt's Haus (Strecker) ; Fiaker - The Setting Sun (Cammarano) ; In the Service of lied (Gruber) ; 's Lercherl von Hernals (Oscar Straus) ; Honour (Colette). 4.45, A ver Using Notes. 5.20, Sei mir gut, schöne Marietta (Ernst ; Weather Report, PARIS (Eiffel Tower), Call FL (2,850 metres) ; 5 kW.- Arnold) Das war Time Signal and Labour Market die Mizzi von der Sandongasse Ernst Report. 5.30, Programme relayed front Höniga- 5.0, Pasdeloup " Concert. 7.10, Weather Report. Arnold); 7.30, " Le Journal Parlé." Liebesfreud, Liebesleid (Kreisler) ; Duet from Jose - Wusterhausen. 8.0, Greff, : - Josef Talk Psycho phine Gallmeyer (Knepler) ; Analysis. Prof. Viennese Humour 8.30, Georg Witkowsti, Talk : (Fortner) ; Eine Lessing. PARIS (Petit Parisien) (340.9 metres) ; 0.5 kW.- Frau wie du, die war' mein Traum 7.0, ' Der treue Soldat," Musical Play in (Arnold) ; 8.45, Gramophone Selections, Talk, News and An- Schön ist mein Wien (Arnold) ; Potpourri, Two Acts (Schubert). 8.30, Cabaret Concert. 9.0, Leháriana (Geiger). Followed nouncements. 9.0, Concert : Overture to Le Timbre by News and Dance News, Sunday Programme Announcements and Sports Music from the Pavillon Excelsior. Notes. 10.0, Dance Music relayed from Voxhaus. d'argent (Saint- Saéus) ; Rip (Planquette) ; Selection for Flute and Orchestra, Tarentella (Saint -Satins); Violin Solo, Rondo from Serenade No. 7 in D Major MADRID (Union Radio), Call EAJ 7 TOULOUSE (Radiophonie du Midi) (389.8 metres) ; (434.8 metres) ; (Mozart) ; Orchestra Suite, The Pearl Fishers (Bizet) ; 3 kW. 8 kW.-12,45, Concert. 8.0, Exchange Quotations 7.0, Chimes, followed by Sextet Concert : Rêverie du soir from the Algerian Suite (Saint -Sains) ; and News. Los cadetes de la reina (Luna) Fantasia on The Ring Spanish 8.30, Recital of Argentine Songs, with Dance No. 3 (Moszkovsky) ; In the Intervals, Guitar Accompaniment. Wagner) ; El carro del sol (Serrano) ; Interlude by News. 8.48, Musical Selections Luis Medina. 8.0, Dance Music relayed from the (Ketelbey), (a) Iu a Persian Market, (b) In a Monastery Garden. : Alkázar. 8.26, News and Announcements. 8.50, " Werther " Opera Selection - (Mas- 9.45, PARIS (Radio senet). Market Prices Review. 10.0, Chimes, followed by Paris), Call CFR (1,750 metres) 6 9.45, Waltz Selections : Donawellen (Ivano- kW.- 12.30, Programme of Columbia vici) ; Sobre las ; El huésped del Sevillano " : Musical Play (Reoyo and Gramophone Olas (Rosas) Gold and Silver (Lehár) ; Records : Nostalgia by Waltz Luca de Tena, and Guerrero) ; followed by News and Lucchesi's South American from Faust (Gounod). 10.0, Waltzes for Accor- Orchestra ; Waltz ether, dion, Banjo : Announcements. 12.30 a,m. ( approx.) (Sunday), To by the Charleston and Pianoforte Waltz Boston from Les Serenaders ; Close Down. Fox -Trot, Kiss and Make Up, by the titillions d'Arlequin (Drigo) ; Venetian Skies ; The Piccadilly Players ; Fox -Trot, Rag Doll, by Debroy Sphinx (Popy) ; Rêve de Pleurs (Translateur). 10.15, Somers Band ; Felix the Cat, by Paul Whiteman North African News. MILAN, Call 1MI (549 metres) ; 7 kW. 7.15, In- and 10.30 (approx.), Close Down. his Orchestra ; dustrial Notes. 7.25, News and Time Signal. 7.32, Duet, Get out and get under the Moon, by Van and Schenck ; Russian Barcarolle by the Choir Variety Concert : Overture to Maritana (Wallace) ; VIENNA (517.2 metres) ; 15 kW. -2.15, Photo - of La Chauve -Souris ; Le Village (Charles ; Selection from Parsifal (Wagner) ; Andante cantabile Freaine) telegraphy Transmission. 3.0, Orchestral Concert. Slavonic Dances in E Minor (Dvorak) by M. Szigeti for Harp, 'Cello and Organ (Braccesco) ; Soprano Solos, J. 4.45, Reading by Gustav Waldau. by (Violin) ; Waltz 5.30, Talk (a) La barba bianca (Tedesco), (b) Siciliana e Bella in A Flat Major (Brahms) by Percy Prof. Willy Schmieger. 5.45, Dr. H. Michel, Talk: Grainger (Piano) ; Fugue G ; Bellina (Sini3aglia) ; Pianoforte Solos, (a) Piccola in Minor (Bach) La Peri Precious Stones. 8.15, " Autumn Storms on Land and (Dukas) ; In the Interval, News. 2.0, Market vecchia partita (Bas), (b) Au jardin de l'enfance Prices Sea " : Recitative by Dr. Franz Borgia and Dora ; and Religious Information. 3.45, Dance Music Grovletz) Quintet Selections (Tchaikovsky), (a) by the Miklosich ; Songs Joss Ghislery Symphonians. In by Robert Almassy. 7.10, Töne Melody Op. 51, (b) Romance without words ; the Intervals, News. Signal, Weather Reading 8.30, Agricultural Report and News. 7.15 " fL:gin- d'Annunzio) ; Soprano Solos (Schubert), (a) ägerlied, Report. 7.30, Pianoforte Lesson by octìum " : Drama in Four Pierre Lucas. Agricultural Acts (Ivo Vojnovic), Barcarolle ; Soprano Song, Einsame Trräne and 8.0, Talk, followed by Translation by Vida Bravacic, followed by Orchestral Market Prices and News. 8.15, Concert arranged by relei (Schumann) ; Harp Solos (Tedeschi), (a) Concert : Overture to Die Fledermaus (Joh. Strauss) ; " Le Matin " : Programme of Chiaraponte, (b) Dramatic Improvisation for Two Symphony Music and Concert Waltz (Moszkovsky) ;. ' L'Education manquée (Chabrier). Song, Drunt' in der Harps ; Quintet Selections, (a) Selection from " In the Intervals, Lobau (Strecker) ; Maton News. Selection from Die einzige Nacht Lescaut (Puccini), (b) The Songs of Italy (De Michell). (Stolz) ; Song, In Schönbrunn (Benatzky) ; Fox -Trot, 9.65, News, followed by Relay of Tzigane Orchestra Love and Kisses (Baker- Silver) Slow Fox -Trot, from the Fiaschetteria Toscana. 10.45 (approx.), POSED (344.8 mettes) ; r5 kW. -8.35, English Sunshine (Irving Berlin) : Original Chinese Blues Close Down. Lesson. 6.50, Talk for Women. 7,10, Economic (Moore) : Tango, Ich hätte Dich so gerne noch einmal Report. 7.30, Programme from Warsaw. 9.0, Time gesehen (Engel- Berger) : Fox -Trot, Under the Moon Signal, Miscellaneous (Snyder) ; MOTALA (1,380 metres) ; 30 kW.-Programme also Items, News and Announce- Boston, So Blue (Sylva) ; Fox -Trot, Sweet for Stockholm (454.5 metres), Böden (1,190 metres), ments. 9.30, Cabaret Concert. 11.0, Concert arranged Marie (Rose) ; followed by Phototelegraphy Trans- Göteborg (416.5 metres), Malmo (260.9 metres), by the Maison Philips. LO a.m. (approx.) (Sunday), mission. Ostersund (720 metres), Sundsvall (545.8 metres). - Close Down. 4.0, Concert of Gramophone Selections. 4,30, Pro- VILNA (435 metres) ; 1.5 kW. -8.15, Poem Recital gramme for Children. 5.15, Relay of a School Festival PRAGUE (348.9 metres) : 5 kW. -8.30, " The Peasant from the Works of Mme. W. Niedziakkowska-Lobac- from Jönkeping (201.3 metres). 8.0, " The Christmas Jacob " (Nedbal), relayed from the National Theatre, zewska. 8.20, Programme from Warsaw. 7.0, News. Fair," relayed from the Town Hall. 8.45, Pianoforte Prague. 9.0, Time Signal, News and Theatre Report 7.30, Programme from Warsaw. Recital from the Works of Chopin : Nocturne in C 9.15, Dance Music relayed from the Hotel Sramota. Minor ; Etude in E Major ; Waltz in A ; Flat Waltz WARSAW (1,111 metres) ; 10 kW. in C Sharp Minor. 7.0, Cabaret Programme, -3.0, Concert of including ROME, Call IRO (447.8 metres) ; 3 kW. 7.10, Sports Gramophone Selections. 4.10, Talk by Prof. L. " Bridge " : A Sketch by Karl Gerhard. 8.0, Topical Notes, News, Exchange Quotations and Weather Szyszkowsky. 4.35, Talk by Prof. H. Moscicki. Talk. 8.15, News and Weather Report. Dance 8.45, Report. 7.29, Time Signal, and Report of the - 5.0, Programme for Children. Music. 9.45 (approx.), Close Down. Inter 8.0, Miscellaneous national Labour Office at Geneva. 7.45, " Othello " Items. 8.80. " Radio -Chronique," by Dr. M. Stepowski. -Opera (Verdi). In the Intervals, Fashion Review 8.58, Time Signal. 7.0, Agricultural Report. 7.5, NAPLES, Call INA (333.3 metres) ; 1.5 kW.-7.50. for Women and Review of Art and Literature. News. 7.30, Concert ; In the Interval, News and Harbour Notes. 8.0, Time Signal. 9.50, Theatre 8.02, News and Close Down. Notes. 9.0 Aviation Notes and Weather Report. 9.5, Schubert Recital. Il : 9,20, " Braccialetto' One Act News. 9.20, Police Announcements and Sports Notes. Comedy ( Traversi). 9.40 (approx.). Review of the SCHENECTADY, Call 2XAD and 2XAF 9.30, Dance Music from Week. 9.50, News. Calendar (21.98 and the Oaza Restaurant. 10.30 9.55, and Programme 31.4 metres) ; 30 kW. -12.0 Midnight, Phil Spitalny's (approx.), Close Down. Announcements. 10.0, Dance Music from the Troca- Musical Programme from New York. 12.30 a.m, dero. 10.30 (approx.), Close Down. (Sunday), Musical Selections from the Eastman Theatre, ZURICH (588 metres) ; 1 kW.-4,45, Weather Report Rochester. 1.0 a.m., Musical Programme from the and Exchange Quotations. Programme OSLO (481.5 metes) ; 1.5 I.W'.- Programme relayed Onondaga Hotel, Syracuse. 5.0, of New by Fredrikestad 1.30 a.m., " The Bark Gramophone Records. 8.0, Chimes from the Zurich (414.8 metres), Hamar (555.6 metres), Bench ." Programme from New York. Notodden (411 metres), 2.0 a.m., Churches. 8.17, Variety Programmes : Accordion Porsgrund (500 metres) and Selections by the Adler Quartet and Contralto Solos Rjakan (448 metres). -8,15, Weather Report and Selections, Songs to the Lute and Humorous items. by Sonia Essin, from New York. 2.30 a.m., " Bonnie 9.0, Weather Report and News. News. 8.30, Talk : Hypochondria. 7.0, Time and Laddies." 9.10, Gramophone 3.0 a.m., " Lucky Strike " Programme Selections of Old and New Dance Music. B 30

www.americanradiohistory.com DECEMBER 12th, 1928. Wtemo 799 Woullca the Warsaw Philharmonie conducted by C. Wilko- Programmes from Abroad. - inirski. 5.0, Programme of Music. B.0, Announce- SUNDAY, DECEMBER 16th. Professor St. Ligon in Humorous Selec- (Radio Barcelona), Call EAJ1 (344.8 ments. 8.20, BARCELONA tions. 6.58, Time Signal. 7.0, Talk. 7.30, Concert. metres) ; 1.5 kW.-11.O a.m.. Chimes relayed from the the Report and Fore- 9.0, \Veather Report and Forecast, News from Cathedral. 11.5 a.m., Weather Press Sports Results. 9.30, Dance Music. 10.30 cast. 1.80, Selections by the Station Trio Gramo- All Times are reduced to Greenwich and (approx.), (approx.), Close Down. phone Records in the Intervals. 2.45 to 5.30 p.m. except No Transmission. 5.30 (approx.), Relay of an Opera, Mean Time and are KAUNAS ;2,000 metres) ; 7 kW. -2.30, Progranune for Agricultural Market Prices and Exchange Quotations Children. 4.0, Talk by J. Ardickas on Economics in the intervals. 8.0 to 8.20 Talks arranged by the where otherwise stated. and Life. 7.0, Concert by the " Aidas " Orchestra. Catalonian Institute of Agriculture at San Isidro. Waltz, " Loin du bal " (Gilbert). 9.30 (approx.), 8.20, Concert by the Station Orchestra. 8.40, Sports Close Down. Notes and Bulletin. 9.0 (approx.), Close Down. arranged by the Academy of Fine Arts on the occa,iou KÖNIGSBERG (303 metres) ; 4 kW.- Programme BERGEN (370.4 metres) ; 1.5 kW. -9.30 a.m., Relay of its Fiftieth Anniversary. 7.30, Concert of Instru- relayed by Danzig (272.7 metres). -8.0 a.m., Recital of Divine Service. 11.30 a.m., Weather Report and mental Music with Vocalists. 9.0, Relay from Warsaw. of Music, including Choral and Instrumental Solos Forecast and General News Bulletin. 4.0, Instru- 9.30, Relay of Light Music from a Restaurant. 10.30 and Address. 10.10 a.m. (approx.), Morning Concert mental and Vocal Concert. 7.0, Concert by the Station ( approx.), Close Down. with Soloists. 11.55 a.m., Relay of Time Signal from Orchestra. 7.50, Topical Talk. .8.30, Pianoforte Nanen, followed by Weather Report and Forecast. ; 1.5 kW. -8.30 to Engebrethsen : Bach's DUBLIN, Call 2RN (319.1 metres) Operetta in Three Acts Recital by Margrethe Gleditsch relayed from Cork. 7.10, " La Chaste Suzanne," French Suite No. 3 in B Minor, (a) Allemande, (b) 11.15 (approx.). -Programme by Georg Okonkowsky. Music by J. Gilbert. Per- and Second Minuets, (d) Gigue. 8.30, Organ Recital from St. Fin Barres Cathedral, the direction of Josef Christean Sarabande, (e) First and Instrumental Pro- formance under Forecast, Late News Bulletin, Cork, followed by Vocal : Hugo Leyendecker. 9.15, Late 9.0, Weather Report and and Weather Report. Musical Director and Time Signal. 9.15, Dance Music. 11.0 (approx.), gramme. 11.0, National Anthem News Bulletin and Sports Results. 9.30, Dance Music. Close Down. 11.15 (approx.), Close Down. 11.0 (approx.), Close Down. 40 4 Programme BERLIN (Königswusterhausen), (1,250 metres) ; FRANKFURT (428.8 metres) ; kW.- LAHTI (1,522.8 metres) ; 35 kW.-Programme also Relay of Chimes from the Garrison relayed by Cassel (252.1 metres). -7.30 a.m. to 8.30 Relay of Sacred kW. 7.55 a.m., of the for Relsingiors (375 metres). -8.0 e.m., Church at Potsdam. 8.0 a.m., Morning Recital and a.m., Morning Recital. 12.0 Noon, Report Service. 9.50 a.m., News from the Press. 10.5 a.m., relayed from Voxnatis, followed by Chimes Wiesbaden Agricultural Institute. 7.30, Programme of Report and Time Signal. Address (approx.), Concert. 10.50 a.m., Weather from Berlin Cathedral. 10.30 a.m. (approx.), Concert Music or Literature. 8.30, Concert. 9.30 11.0 a.m., Relay of Church Service in Swedish. 3.0, relayed from Voxhaus. 12.45, Experimental Trans- Dance Music. 11.30 (approx.), Close Down. Concert by the Station Orchestra. 4.57, Time Signal Talk. 5.0, Series of Talks Concert by mission of Pictures. 3.0, HAMBURG, Call HA (in Morse) (394.7 metres) ; 4 and Weather Report and Forecast. 5.10, arranged by the " Deutsche Welle," followed by metres), the Station Orchestra. Songs of Finland by Pahlman. Selections kW.- Programme relayed by Bremen (272.7 Concert or Opera. 9.15, Press News. 9.30, metres), and Wet (254.2 metres). 7.0, Concert. 7.45, General News Bulletin given in Music. (approx.), Close Down. Hanover (297 - 8.30 (approx.), of Dance 11.30 7.25 a.m., Time Signal. 7.30 a.m., Weather Report Finnish followed by News in Swedish. Down. (Voxhaus), (484 metres) ; 4 kW. 7.55 a.m. and Forecast followed by General News Bulletin. Close BERLIN Week's Legal Relay of Church Chimes from Potsdam. 8.0 a.m., 7.50 a.m., Economics Talk. 8.0 a.m., The LANGENBERG (484.8 metres) ; 20 kW.- Programme Morning Concert with Vocal and Instrumental Solos Notes. 10.0 a.m., Talk. 11.55 a.m., Time Signal also for Aix -la- Chapelle (400 metres), Cologne (28; followed by Chimes from Berlin Cathedral. Address relayed from Nauen. 12.5 (For Hamburg and Kiel) : metres) and Münster (250 metres). -8.45 a.m., Lesson in the interval. 10.30 (approx.), Concert. 1.0, Morse Concert. 12.5 (For Bremen) : Musical Selections. in the Art of Self- Defence by Dr. Ludwig Bach. 7.15, Talk. : Gramophone Selec- of Lesson for Beginners, by Hans W. Priwin. 3.0, 12.5 (For Hanover) Popular a.m., Alfred Dormans : Review in Esperanto the 3.30, Recital of Music. 8.0, Talk. 7.0, Concert. tions. 1.0, Funkheinzelmanñ s Programme for Programmes of the Week. 7.15 a.m., Lute and Guitar 8.30 (approx.), Concert, followed by Weather Report, Children. 6.30, Transmission of the Hamburg School Lesson. 7.85 a.m. to 7.55 a.m., Esperanto Lesson. Late News Bulletin and Sports Notes. 9.30, Dance of Physical Culture. 0.40, Sports News. 6.55, Weather 8.0 Trinity Church Chimes. 8.5 a.m., Catholic or 8.30. a.m., Music. 11.30 ( approx.), Close Down. Report and Forecast. 7.0, Concert flay. Festival with Musical Items and Adunes;. 10.0 a.m., followed by Weather Report and Late News Bulletin Philological Talk by Fritz Worm. 10.35 a.m. ( approx.), BEZIERS (158 metres) ; 0.0 kW. -8.30, Sports Gramophone Programme of Light Music. 10.50 (For Hamburg, Agricultural Talk. 12.0 Noon, Afternoon Concert. Bulletin. 8.45, Programme of Light Report for the North Sea Concert Maison Relia Pathé Records. Bremen and Kiel), Weather 1.30, Talk : Wireless and Literature. 180, Music arranged by the and Baltic. 11.0 (approx.), Close Down. (approx.), Sports Notes. 10.30 (approx.), Close Down. of Orchestral Music. 8.35 5 12.10, Concert 7.0, Popular Concert. Late News Bulletin, Sports relayed HILVERSUM (1,071 metres) kW.- Music. BRESLAU (322.6 metres) 4 kW.- Programme by the Station Orchestra. 2.10, Orchestral Concert. Results and Notes and Programme of Light by Gleiwitz (329.7 metres). -8.15 a.m., Chimes relayed Bulletin and Sports Results. 11.0 (approx.), Close Down. a.m., Catholic Recital of 7.40, Time Signal, News from Christ Church. 10.0 7.55, Operatic Performance, Gounod's " Faust." relayed Music with Address in the Interval. 11.0 a.m., LEIPZIG (385.8 metres) ; 4 kW.- Programme Guessing Competition. 10.40 (approx.), Close Down. by Dresden (275.2 metres). -7.30 a.m., Relay of Organ Musical Programme. 1.0, Programme 1.10, Talk or Literary Programme. 1.85, Hints for HUTZEN (340.9 metres) ; 4 kW.- Transmits from 5.40 Recital. 8.0 s.m., Vocal and Instrumental the Chess Lover. 2.0, Stories for Children. 2.30, on 1,852. metres. -8.30 a.m., Morning Service relayed 10.0 a.m., Talk. 10.30 a.m., Talk. 11.0 a.m., Instru- Farmers. 7.0, Christmas Oratorio by J. S. front Gorinenem (Hoogstraat), Sermon by the Rev. mental Concert. 12.0 Noon, and 12.80, Agricultural Talk for Press and Review News Announcements. 9.30, M. Hummelen, Minister ; At the Organ : Heer Talks. 1.0, News from the Foreign Bach. 9.0, Late and R. K. Musical or Dance Music. 11.0 (approx.), Close Down. O. van der Kleyn. 12.10, Musical Selections by the of the Events Abroad. 1.45, Talk. 3.0 Talk. 2.10, Orchestral Literary Programme. 4.0 Concert. 5.30. Talk. 1.5 kW. -5.0, Light K.R.O. Trio. 1.1.0, Talk. 1.40, BRUSSELS (508.5 metres) ; Concert. 5.30, Relay of Church Service (on 1,852 6.30 Concert or Play. fi.0, Comedy by Prosper Orchestral Music. 6.0, Children's Programme from Le by Hans Peter Schmiedel. 9.0. Programme. metres). 7.10, Talk. 7.50 (approx.), Orchestral Mernmée, produced Thêátre des Enfants. 8.30, Musical " Le Petit Choeur " Sports Results. 9.30, Dance Music relayed from. of Orchestral Concert. 10.25, Epilogue by 7.80, La Radio -Chronique. 8.15, Concert of Mr. Jos. H. Pickkers. 10.40 Btrlin. 11.30 (approx.), Close Down. News and Announcements. 11.0 under the direction Music. 10.15, Late (approx.), Close Down. (approx.), Close Down. LYONS (Radio Lyon) (291 metres) ; 1.5 kW. 7.80, -LES -PINS (Radio L.L.), (244 metres) 1.5 kW. Le Journal Parlé with General News Bulletin, News BUDAPEST (556.6 metres) 20 kW. -8.0 a.m., ¡BAN Miscellaneous Announcements. and Beauty Notes. 9.0 a.m., -1.0 to 2.0, Concert by the Casino Municipal Orchestra from the Press and General News Bulletin : Pianoforte Solos by and Programme for Children. 9.0, General News 8.0, - Instrumental Concert of Morning Service and Sermon. 11.15 a.m. ; Relay Concert with Soloists. Madame Ducharne ; Violin Solos by M. Camand and (approx.), Programme of Music. 2.30, Talk for Bulletin. 9.15, Instrumental au Concert or 10.0, Dance Music by the Casino Orchestra. 10.30 'Cello Solos by M. Testaniére ; L'Invitation Farmers. 3.15, Concert. 8.30 (approx.), Voyage (Charpentier). 9.0 (approx.), Close Down. Operatic Relay. 9.30, Dance Music. 10.30 (approx.), (approx.), Close Down. Call EAJ7 (434.8 metres) Close Down. KALUNDBORG (1,153 metres) ; 7 kW.-Programme MADRID (Union Radio), Divine 1.5 Programme relayed by Salamanca (EA J (283 metres) ; 4 kW.-Progranune also for also for Copenhagen (337 metres).-9.0 a.m., kW.- COLOGNE 22) (405 metres). -11.30 a.m., Concert by the Municipal Aix -la- Chapelle (400 metres), Langenberg (468.8 Service relayed from Copenhagen. 10.30 a.m. to Report and Band from El Retiró. Conductor : Maestro Villa. (250 titres). -6.45 a.m., Lesson 10.40 a.m., ( Kalundborg only), Weather metres) and Minster Chimes and Time Signal. 2.5, Concert of Popular in Self Defence. 7.5 a.m., Précis in Esperanto of the Forecast from the Copenhagen Meteorological Institute. 2.0, and Guitar German Instruction under the Music by the Station Orchestra with the collaboration Programmes of the Week. 7.15 a.m., Lute 12.0 Noon to 12.25, Interlude by Luis Medina; by 011y Wirtz Koort. 7.35 a.m., Esperanto auspices of " Radiolytteren." 12.30, Lesson in French of Celso Diaz (violinist) Instruction (Kreisler). 3.30 to 7.0. No Transrission. Lesson. 8.0 a.m., Sacred Recital with Address. arranged by " Radiolytteren." 2.15 (approx.), Instru- Liebesfreud only), Weather 7.0, Chimes. 7.5, Selections by the Station Sextet. 10.0 a.m., Talk on the German language by Fritz mental Music. 5.50 (Kalundborg Orchestra (approx.), Agricultural Talk. Report and Forecast from the Meteorological Institute 8.0, Dance Music Selections by the'Palermo Worm. 10.35 a.m. 8.30, to 10.0, No Transmission. 12.0 Noon, Afternoon Concert. 1.30, Wireless Literary 6.0, News from the Press. 8.15, Time Signal. 8.30, from the Alkazar. Popular from the Town Hall, 10.0, Chimes and Tinte Signal. 10.5, Regimental Talk. 3.30, Concert of Popular Music. 7.0, Talk. 7.0, Chines relayed followed by ; in Band Concert. 12,0 Midnight, Chimes : Der Vetter auf Besuch " Lilac Time," Musical Play Concert ; ln the Intervals Copenhagen. 7.5, Palermo Orchestra and Announcements, Sports Notes and Three Acts by Dr. A. Winner and Heinz Reichert. Dance Music Programme by the Late News a.m, (approx.) Programme. 11.0 (approx.), Close Music by Schubert. Translated into Danish by relayed from the Alkazar. 12.30 Light Dance Music Down. Down. Johannes Dam and Paid Sarauw. The Orchestra (Monday), Close conducted by Ernst Hye- Kundsen. In the interval k\V. Opening Call OCK (400 metres) ; 1.5 kW. -8.30, Organ MILAN, 1MI (549 metres) ; 7 -9.0 a.m., CORK, between Acts One and Two, Press News. 10.0, Dance Lesson in English. 9.30 a.m. to 10.15 a.m., Recital by J. T. Horne, relayed from St. Fin Barre's the Palace Hotel, the Orchestra Signal and by Concert with Soloists. Music relayed from Vocal and Instrumental Recital of Sacred Music. Cathedral, Cork, and followed by Teddy Petersen. In the Interval at by the National Anthem and Weather Report and conducted 11.30 a.m., Time Signal. 11.35 a.m., Concert 11.0, 11.0, Town Hall Chimes relayed from Copenhagen. No Transmission. ( Down. Station Quartet. 12.30 to 3.0, Forecast. 11.15 approx.), Close Close Down. 11.30 (approx.), ILO, Opening Signal. 3.5, Concert by the Station 1.5 kW. -9.15 a.m. to 10.45 at CRACOW (566 metres) : 10 kW. a.m., Quintet. 43.5, Concert by the Tzigane Orchestra from a Cathedral. KATTOWITZ (422 metres) ; -9.15 - a.m., Morning Service relayed Time Signal. the Fiaschetteria Toscana. 5.0 to 8.55, No Trans of Fanfare front the Church of Relay of :doming Service. 10.56 a.m., and 10.56 a.m., Relay Report and Forecast. 11.15 a.m., mission. 6.55, Opening Signal. 7.0, News Notre Dame, followed by Time Signal and Weather 11.0 a.m., Weather Talk by C. A. Blanche. 7.25, Popular Concert by the Station Quartet. 1.0, Talk, Announcements. 7.15, Report. 11.10 a.m., Relay from Warsaw. 1.0 and Sports News. 7.30, Time Signal. 7.35, The Pearl - The Farmer's 1.20 and 1.40, Two Talks for Farmers. 2.0. Weather 1.20, Two Agricultural Talks. 1.40, by Bizet ; At end of Act Two, Sports Report. Report. 2.15, Popular Symphony Concert relayed fishers," Opera Chronicle by Dr. St. Wasniewski. 2.0, Weather from the Opera Notes and News from the Stefani Agency. 10.30 from 4.20, Talk. 5.0, from Warsaw : Fantasia on Themes 2.15, Concert relayed Warsaw. by the Orchestra of (approx.), Close Down. Programme from Warsaw. 6.0 to 7.30, Transmission " Verbum Nobile " (Moniuszko) B 31

www.americanradiohistory.com 80o DECEMBER 12th, 1928. Programmes from Abroad. - Sunday, ment, relayed front Washington, D.C. 2.15 a.m., MOTALA (1,380 metres) ; 3u kW. -Programme also December 16th. Atwater Kent Hour, relayed from New York. 3.15 a.m., for Stockholm (454.5 'metres), Boden (1,190 metres), Correct Time. 8.17 a.m. Relay Göteborg of Grand Opera from (416.5 metres), Malmo (260.9 metres), New York, followed by Television Signals. 4.30 a.m. Ostersund (720 metres) and Sundsvall (545.6 metres).- All Times (approx.), Close Down, 10.0 a.m., Relay of Divine Service are reduced to Greenwich from a Stockholm SEVILLE (Union Radio), Church. 4.55, Carillon relayed from the Town Hall at Call EAJ5 (375 metres) : Mean Time and are p.m. except 2 kW.-2.0 to 3.0, Concert by the Station Orchestra Stockholm. 8.15, Talk on " The Poet Viktor Rydberg," and Gramophone followed by Centenary Programme in his memory. Records. 9.30, Orchestral Concert 8.15, where otherwise of Music by Spanish Composers. Late News Bulletin and Weather Report and Fore - stated. 11.0, Flamenco cast. 10.0 (approx.), Songs and Popular Dance Music. 11.30 (approx.), Close Down. Close Down. MUNICH (535.7 metres) 4 kW.- Programme re- layed by STAMBOUL (1,200 ; 5 Augsburg (566 metres), Kaiserslautern Press News. 7.45, The Radio -Paris Circus. 8.15, metres) k1V.- -3.30, Concert. (277.8 metres) and Nuremburg Symphony 4.30, Stock Exchange and Prices of Cereals. (241.9 metres). -10.0 Concert by the Station Orchestra, con- Concert 5.15. a,m., Relay of Chimes from the Munich Town Hall. ducted by M. Eugène Bigot. of Turkish Music. 7.30, Weather Report and In the intervals : News Forecast, followed 10.10 a.m., The Bavarian Wireless Weather Chart. from the Evening Papers and Late News Bulletin. by Time Signal. 7.40, Talk on the 12.0 Noon, Time Signal, Weather Report and Forecast 10.30 (approx.), Close Down. History of Music. 8.0, Concert by the Station Orches- and Programme Announcements. 2.0, Musical tra. 9.0, Late News Bulletin. 9.30 (approx.), Close PITTSBURGH. Call KDKA (83 Down. Programme. 7.0, Concert. 9.0, Concert of Orchestral and 27 metres) ; 25 - Music. In kW. -4.0, Sessions Clock Chimes, followed by Relay the Interval at 9.20, Late News Bulletin. of STUTTGART (379.7 metres) ; 4 10.30 (approx.), Close Down. Church Service. 8.80, Programme arranged by the kW.-Programme Whitehouse Coffee relayed by Freiburg (577 metres). -10.15 a.m. (approx.), Company, relayed from New York. Vocal NAPLES, Call 1NA (333.3 metres) ; 1.5 kW. -810 7.0, " Roxy's Stroll," and Instrumental Concert. 11.0 a.m., Orchestral Lesson Programme from WJZ, New Concert a.m., in French. 9.0 a.m., Sacred Recital. York. 9.45, Relay of Service from followed by Gramophone Records. 1.0, 8.45, Children's Corner. Vocal the Shadyside Programme for Children. 4.0, and Instrumental Presbyterian Church, with Sermon by the Minister, 2.0, Talk or Reading. 3.0 Concert. 4.30, Time Signal. 7.30, News. 7.50, the Rev. Hugh Thomson Kerr. (approx.), Concert. 7.15 (approx.), Concert or Opera Report of the Naples 120, Programme followed by Harbour Authorities. 8.0, Time of Orchestral Music. 11.30, Concert by Late News Bulletin and Sports News. Signal. 8.02, Concert by the Station the Whittall 10.30 (approx.), Close Down. Orchestra with Anglo- Persians, from New York. 12.0 Midnight, Vocalists : ' Ambo nati in questa valle," from Linda Sessions Clock Chimes, followed by Relay of Service TOULOUSE (Radiophonie du di Chamounix, by Donizetti, Baritone Solo by Raff. from Midi) (389.6 metres) the Calvary Episcopal Church at Pittsburgh. 8 kW.- 12.30, Meteorological Report and Local Aulicino, accompanied by the Orchestra. 9.0, Sports Sermon by the Minister, Market Results. Calendar the Rev. E. J. Van Etten. Prices. 12.45, Programme of Instrumental 9.55, and Programme Announce- 1.0 a.m. (Monday), Musical Programme Music Correct ments. 10.0 (approx.), Close Down. from the LO, Time. L5, Concert (continued). National Broadcasting Company, New York. 1.45, News Bulletin. 8.0, Market Prices Collier's 1.15 and Stock ' OSLO (481.5 metres) ; 1.5 kW.-- Programme relayed a.m., Radio Hour from New York. 2.15 a.m., Exchange Quotations from Paris. 8.14, News from the by Fredriksstad (434.8 metres), Ramer (555.6 metres), Concert by the Utica Jubilee Singers relayed troni Parisian Newspapers. 8.30, Concert of Instrumental Notodden (411 metres), Porsgrnnd (500 metres), Rjukan WJZ. New York. 2.45 a.m., El Tango Romantico Music. 9.0, Time Signal. 9.15, Concert (continued). (448 metres). relayed from New -9.50 a.m., Carillon. 10.0 a.m., Divine York. 3.15 a.m., Longine Time. 10.5, Ten Minutes of Dance Music : West End Blues Service relayed from St. Saviour's Church. 6.15, 3.30 a.m. (approx.), Close Down. (Oliver). 10.15, " Le Journal sans papier " with Weather Report and Forecast and Press News. News from North Africa and Late 7.0, POSEN (344.8 metres) ; 1.5 kW. -9,15 a.m. to 10.45 News Bulletin. Time Signal. 8.15 (approx.), Recital of Music. 8.30, a.m., Relay of Morning 10.30 (approx.), Close Down. Weather Report and News Service and Sermon. 11.0 from the Press. 8.45, a.m Time Signal. 11.05 a.m. VIENNA (517.2 Topical Talk by a Journalist. 9.15 (approx.), Dance and 11.30 a.m., Two metres) ; 15 kW. -Programme re- Talks for Farmers. 2.15, Symphony Concert relayed layed by Graz (357.1 metres), Innsbruck Music relayed from the Hotel Bristol. 1L30 (approx.), from (294.1 metres), Close Down. Warsaw. 4.20, Talk. 4.50, Talk. 7.30, Violin Klageafart (27.2.7 metres), and Linz (254.2 metres). Recital by M. Edmond - Gizejewskl. (At the Piano : 9.20 a.m., Musical Recital. PARIS (Ecole Supérieure), Professor 10.0 a.m., Concert by the Call FPTT (458 metres) ; François Lukasiewicz) : Two Vienna Symphony 0.5 Gavottes by Orchestra and Soloists. 3.0, kW.- Programme relayed at intervals by the Rameau and Martini. 8.30, Musical Programme. 9,0, Concert of Orchestral Music. 6.30, Relay from the following stations : Bordeaux PTT (275 metres), Time Signal. 9,5, Variety Item. Opera House, followed Concert Eiffel 9,20, General by of Orchestral Tower (2,650 metres), Grenoble (416 metres), News Bulletin, 10.0, Light Music. 11.0 (approx.), Selections and Experimental Transmission of Pictures. Lille (264 metres), Limoges (285 metres), Lyons PTT - Close Down. 10.15 (approx.), Close Down. (480 metres), Marseilles (303 metres), Rennes (280 PRAGUE (348.9 metres) ; 5 VILNA metres), Toulouse PTT (260 metres). -8.0 a.m., kW. -8.0 a.m., Sacred (435 metres) ; 1.5 kW.- -9.15 a.m. to 10.45 a.m., News Bulletin Recital. 10.0 a.m., Concert. 12.05, Talk on an In- Relay of Cathedral Service. 10.56 a.m. and Time Signal. 9.25 a.m., Inter- dustrial Subject. to 4.20, Pro- national Tinte 3.80, - Concert. 4.30, Workers' gramme relayed from Warsaw. 10.56 Signal and Weather Report. 12.0 Transmission. a.m., Time Noon, Concert. 1.0, Le Journal 5.0, Programme for German Listeners. Signal. 11.0 a.m., General News Bulletin. 11.10 " de France Economi- 5.30, Sports Talk. a.m., que." 1.30, Concert organised by the General Associa- 6.0, Concert or Play. 9.0, Time Symphony Concert of the " Philharmonie de Varsovie," tion of French Wireless Signal and Late News Bulletin. 9.20, Light Musical devoted to the Works of French and Italian Composers. Listeners. Ballet Music Selections. from " Sylvia " (Delibes). 2.30, Symphony Concert 10.15 (approx.), Close Down. Intermezzo from the Opera " Cavalleria Rusticana " arranged by the Paris paper RABAT, (Mascagni) rendered by the Orchestra under the Le Journal." 4.0, Call PTT (418 metres) ; 2 kW. -12.30 to direction Pasdeloup Symphony Concert by M. Rhené Baton 2.0, The Radio Maroc Orchestra of J. Oziminski. LO to 2.0, Three Talks for in a Programme of Farmers. Orchestral and relayed from the Champs Elysées. 6.30, "Le Light Music. 4.0 to 5.0, Concert by a Military Band. 2.15, Concert. 5.0, Musical Radio Journal de France." 8.15, Sports Talk. 8.80, 8.15, Le Selections. 6.45, General News Bulletin and Time Orchestral Concert. 10.30 (approx.), Dance Music News'Bulletin and Announcements. Signal. 7.0 to 10.30, Programme relayed from Warsaw. 8.30, Orchestral 7.0, Talk. Concert. relayed from the Coliseum de Paris. 12.0 Midnight 10.30, Dance Music, relayed from thera 7.30, 9.0, Aviation Report and (approx.), Close Down. " Chaumière de Weather Forecast. 9.5, General News Bulletin. 9.20, Rabat." 120 (approx.), Close Down. Sports PARIS (Eiffel Tower), News and Police Notes. 9.30, Dance Music Call FL (2,850 metres) ; O kW. RIGA (528.3 metres) ; 4 kW.-8.0 relayed -7.58 a.m., Time Signal a.m Relay of from the "Oaza" Restaurant, Warsaw. on 32.5 metres. 9.24 a.m., Church Service in German. 9,15 a,m., Sacred Service 10.30 (approx.), Close Down. Time Signal on 2,650 metres. 5.0, Relay of Pasdeloup (in Latvian) relayed Concert. from the Mara Church. 12.0 Noon, 7.10 to 7.20, Weather Report and Fonxast. Songs and Music for Children. WARSAW (1,111 metres) ; 10 kW. -9.15 a.m. 7.80, " Le Journal 3.0, Concert by the to Parlé par T.S.F." The Day's Riga Wireless Orchestra (Conductor, Arved Parups). 10.45 a.m., Relay of Cathedral Service. 10.58 a.m., Sporting News with Racing Results from " Paris CO, Programme of Talks. 6.0, Concert. Time Signal. 120 a.m., Aviation Route Report and Sport." 7,58, Time 8.0, Weather Signal on 32.5 metres. 8.0 to Report. 9.0, Musical Selections, relayed from the Weather Forecast. 11.10 a.m., Symphony Concert 9.0, Vocal and Instrumental Concert. 10.28, Time Café de l'Opéra. 10.0 (approx.), from the " Philharmonie de Varsovie." 1.0 Signal on Close Down. to 2.0, 2,650 metres. 11.15 ( approx.), Close Down. Three Agricultural Talks. 2.0, Weather Report and ROME, Call 1RO (447.8 metres) 3 kW. PARIS (Petit Parisien), (340.9 -8.30 a.m., Forecast. 2.15, Symphony Concert. 4.20, Talk. metres) ; 0.5 kW.- Opening Signal, followed by Lesson in German. 4.45, Aviation Talk. Popular Concert, 8.45, Popular Gramophone Selections. 8.50, Talk. 9.0 a.m., Vocal and Instrumental 5.0, 8.0, Variety 8.55, News from the Concert. 9.45 a,m, Items. 8.20, Talk. 6.45, General News Bulletin and Press. 9.0, Concert with Items to 12.0 Noon, No Transmission. 12.0 Noon, Opening Time by well -known artistes from Signal. 7.0, Talk by C. Jablonowski : Diver- the Paris Opera and the Signal. 12.5 to LO, Concert by the Station Trio. tissements intellectuals. Opéra -Comique. 9.25, General News Bulletin. LO 4.0, 7.30, Concert by the Polskie 9.30, to No Transmission. 4.0, Opening Signal. Radio Orchestra, conducted by J. Ozimmski: Over- Symphony Concert--. Conductor : Professor Estyle, 4.5 to 5.30, Variety Concert. of the Paris 7.10, Talk for Farmers. ture to the Opera " Ruslan and Ludmila " by Glinka. Conservatoire : Finale from the Spanish 7.15, Sports Notes and News from the Stefani Symphony for Violin and Orchestra Agency. 9.0, Aviation Report and Weather Report and Fore- (Lalo); Violinist : 7.29, Time Signal. 7.31, Talk. 7.45, Concert by the cast. News from Polish M. Bellanger, of the " Concerts Colonne " Grand 9.5, the Telegraph Agency. and the Symphony Orchestra ; Concerto in D Major for 9.20, Police and Sports News. Conservatoire Concert Society. 10.0, Late News Violin with Orchestral 9.80, Dance Music by Accompaniment (Pagannini) ; the Bulletin. 10.15, Concert of Orchestral Musk. Violinist, Orchestra at the " Oaza " Restaurant, Conductor: 110 Maria d'Alba. 9.50, Late News Bulletin. W. Roszkowski. 10.80 (approx.), Close Down. (approx.), Close Down. 10.0 (approx.), Close Down. PARIS ZAGREB (309.2 metres) 0,7 kW. -10.0 (Radio I-L.), (370) 1 kW.-12.30, Radio SAN SEBASTIAN (Union Radio), Call a.m., Liberté Transmission. ; EAJ8 (400 Symphony Concert by the Croatian Philharmonic General News Bulletin, followed metres) 0.5 kW. -10,0, Concert by the Grand by Concert of Instrumental and Vocal Music Casino Orchestra. Orchestra : Balkansphonia (Josip Slavenski). 40, by the 12.0 Midnight (approx.), Close Dance Music Charles Seringes Trio. 1.0, Carillon de Fontenay. Down. Programme relayed from the Club - -3.0, Popular Dance Music. 9.0, Vocal and Instrumental Cabaret. 6.45, Wireless Notes. 7.0, Opera Relay Concert. SCHENECTADY, Call 2XAD from the National Theatre, Zagreb. 10.0, Carillon de Fontenay. 10.15 ( approx.), and 2XAF (21.96 and In the Intervals: Close Down. 31.4 metres) ; 30 kW.-3.30 (approx.), Relay News and Announcements and Weather Forecast. Church of PARIS (Radio Service. 8.30, Recital of Organ Music by 10.0 (approx.), Close Down. Paris), Call CFR (1,750 metres) ; 6 Elmer A. Tidmarsh, relayed front kW. -8,0 a.m., General News Bulletin the Union College ZURICH (588 metres) 1 kW. -10.0 and Press News. Memorial Chapel at Schenectady, N.Y. a.m., Concert 8.80 a.m., Physical Culture Instruction by Dr. Diffre. 9.0, Dr. S. relayed from the Capitol Theatre. 11.0 a.m., Weather Parkes Cadman 's Talk for Men, relayed from New York, 12.0 Noon, Religious Address, followed by Recital 10.80, Violin Report and Forecast. 11.30 a.m., Programme by the of Sacred Music Recital by Arcadie Birkenholz, relayed Zürich Station Orchestra. arranged by " La Vie Catholique." from New York. 11.0, The American 3.0, Concert by the Castel- 12.30 News from the Press. Concert Legion Band lano Orchestra at the Carlton Elite Hotel. 8.30, Time 12.45, by the Half Hour, relayed from Boston, Mass. 11.30, Acous- Albert Locatelli Orchestra with selection by Bilboquet ticon Signal. 6.33, Protestant Address. 7,0, Programme in the interval. Programme from New York. 12.0 Midnight, The relayed from 4.80 Concert of Gramophone Music Old Company's Programme, Basle. Recital of Music at St. Martin's arranged by " L'Industrie Musicale." relayed from New York. Church. 9.0, Weather Report, Late News : Bulletin In the interval 12.30 a,m. (Monday), Relay from the Capitol Theatre, Press News. 6.45, Gramophone Records. 7.30, New and News from the Neue Züricher Zeitung. 930 York, 2.0 a.m., Talk on the American Govern- (approx.), Close Down. B 32

www.americanradiohistory.com z ° . . wAp.Il. 8or DECEM,VLR 1211e, ro-,. o

9 ïe a rs rro re, Commerct

Automatic S.O.S., Position Finding, Less Jamming of Broadcast, Beam Telephony. By LIEUT. =COLONEL CHETWODE CRAWLEY, M.I.E.E.

r1HE advances made in all branches of wireless com- of 1912. Usually there is a new Convention every five munication during the past year have been quite years, but since 1912 it had been found impracticable to extensive, though perhaps rather less spectacu- arrange for an international radio conference until 1927, as was lar, than in recent years. In fact, the technical side of although the urgent need for such a conference wireless has now reached a stage where it has time to apparent to anyone interested in wireless communica- pause a little and consolidate its position. Of course, tions. the advent The 1912 Convention had dealt only with regulations the days of ' ` hit or miss " are long past, but with one another of short waves three years ago did have the effect of governing the communication of ships the melting -pot many problems which then and with the shore, as at that time the use of wireless throwing into Now, to have been solved, and it is only during this was practically confined to such communication. seemed and the new last year that we have sailed into less troubled waters. of course, the situation is quite different, -lived, many new avenues of Convention, besides overhauling the old ship and shore But the pause will be short point- advance are opening up, and it will not be long before regulations, lays down regulations for governing is in use again for facsimile transmission to-point communications, aircraft services, broadcasting, the melting -pot is telephony. Later on, we shall be asked and amateur working. As all wireless communication and short -wave is essential, with television, and even, perhaps, the dis- conducted by means of waves in the ether, it to struggle that the various services by wireless ;. but we must check these if interference is to be avoided, tribution of power and this inter- alluring visions and come to the more prosaic attainments should be confined to definite wavelengths, of was the most important, of 1928. national allocation waves and, indeed, the most difficult, work with which the con- The International Convention. ference had to deal. The Convention now lays down, for waves, from In the autumn of 1927 an International Radiotelegraph all the different services, definite bands of held in Washington, and the resulting 5 to 30,000 metres, some of these bands being exclusively Conference was to Convention was promulgated in the early confined to a particular service, others being allocated International interference of last year. This Convention, which came into two or more services in cases where mutual part importance. force on January 1st this year, supplants the Convention is unlikely, or at any rate is not of great

x- www.americanradiohistory.com _. ;f' ll; fi r ?,10-,141 802 Wfime@go DECEMBER s21h, ;928. L`voo TIlcó A Year's Progress in Commercial Wireless. - that if the latter is omitted In actual practice much the former may be missed of the spirit of the new regu- by British ships within range, lations was already in and in consequence it being as a result of the advances is becoming general to made in wireless technique use both signals. since the 1912 Convention, The advantage of having directional and during the last year most receiving ap- of the letter of the new paratus in ships has become more appreciated regulations has already been put into operation. by ship- owners during the last year. With this apparatus a Automatie Distress Signal, ship is able to obtain its bearing from any station or The most important advance in maritime signalling ship fitted with wireless, and in addition wireless beacon during the year has been the fitting of British ships with stations are being erected at various places all over the automatic apparatus for receiving the alarm signal. This world for the purpose of allowing ships which are equipped with directional receivers to obtain bearings from these beacons. The percentage of British ships fitted with directional receivers compared with the total number of British ships fitted with' wireless has in- creased during the year to about 17 per cent. The design of ships' apparatus has tended towards the introduction of interrupted continuous wave appara- tus in place of spark apparatus, as it is laid down in the new Convention that ships equipped after the Ist of January, 1930, must be fitted with continuous -wave transmitters, except in the case of very small instal- lations. This regulation will tend to reduce interference in maritime signalling generally, and especially the in= terference caused by such signalling to the reception of broadcasting programmes in coastal areas, as continuous - wave transmission, being more sharply tuned than spark transmission, causes less interference. Broadcastlis- teners have indeed been well looked after by the new Convention,_ as broadcasting stations have been given bands of waves which cannot be used by other services. Two waves which have hitherto been used by ships-- the 3oo -metre wave and the 450 -metre wave -are not to be so used in future in regions where they might inter- fere with the reception of broadcast programmes. Similar regulations have been laid down for the coast stations which work with ships, and during the year several of our coast stations have had their spark in- stallations replaced by interrupted continuous -wave sets. The policy of fitting our coast stations with directional receivers, so that they may be able to give a ship its bearing from the station, has been continued, and about 8,000 bearings have been given during the year. But ships which are themselves fitted with directional re- ceivers Directional aerial receiving equipment installed at a coast station often require to obtain a bearing for naviga- so that ship direction and location can be determined. (Port- tional purposes from places ;. patrick station.) where no coast stations are established, and during the year a considerable r signal consists of a series advance of twelve dashes sent in one has been made in plpviding wireless beacon minute, the duration of each dash stations for being four seconds, this purpose. Six of these stations are now and the duration of each space between in operation two dashes, at suitable points round the coasts of the British Islands, one second. It is used solely to announce that the and several more distress are in hand. In a few cases sub- signal is about to follow, and, when received marine sound signals are on the special automatic emitted from the station at apparatus, it actuates an elec- the same time as the wireless signals, tric circuit so as to ring so that ships a bell which calls the operator fitted with the necessary apparatus can obtain, to the instruments. British ships are, not only as a rule, allowed a bearing, but also their position, by noting the to reduce their operating staff if they are differ- fitted with ence in time between the reception of the wireless and this apparatus, and there are now nearly Boo ships so the sound signals. fitted. This alarm signal, and the use of automatic The results of extensive experimental receivers, have been recognised work on direc- in the new International tional wireless carried out by the Radio Convention, but up to' the present Research Board such apparatus has during the last five years has been published. been fitted only in British ships. It has It was not been laid found that the bearings of transmitting stations by day down internationally - that the distress signal must be were reliable to an extreme error of four degrees, the preceded by the alarm signal, but it is now well known great majority of readings being correct to within two 2

www.americanradiohistory.com DECEMBER 12th, 1928. Wfirnhoo 8o3 WOOrlo A Year's Progress in Commercial Wireless. - degrees. During darkness results were far more erratic, but, fortunately for ships' navigation, these variable errors were not encountered up to a range of about one hundred miles when the transmission was entirely over sea. These results of the Radio Research Board's ex- periments are confirmed by observations made in various countries throughout the world. In addition to the work carried out at the coast sta- tions there is a large volume of telegraph traffic con- ducted with passenger ships at long ranges through a Post Office medium -power station. A new, up -to -date transmitting station for this purpose was opened during the year at Portishead to replace the one at Devizes which had been in use since the war. The receiving and operating station remains as before at Burnham -on- Sea, but the whole service has been extended, and a long- range, short -wave service is now available in ad- dition to the improved long -wave service. Nearly one and a half million words were dealt with at this station during the year. Short Waves for Ships. Technical difficulties have arisen in adapting short - wave installations to ship conditions, and so far only a few ships have been fitted. Great ranges are often obtained ; for instance, Portishead is frequently in good communication with ships in the South Atlantic and the Indian Ocean, but the communication cannot yet be con- sidered as reliable. However, the work carried out during the year may be taken as proving that a great future is in store for short -wave communication with ships. When at last this comes to its own, no ship need ever he out of direct touch with any country, but Ship's direction -finding aerial. we have some way to go yet before that is a practical proposition. During the year, wireless telephony has been fitted in a few fishing fleets, and, as an experiment, in a few large passenger ships. In some of the fishing fleets it has proved useful, but otherwise it has made little advance in maritime signalling. A set for working with ships has been installed in the coast station at the Humber. Marine Telephony. The obstacles in the way of wide adoption are that telephony causes more interference than telegraphy, for equal power the range obtainable is less, the difficulties of technical mainten- ance are about the same for the two ,vstems, and telephony presents Lan- guage difficulties which are not present in telegraphy. But, on the other hand, the supreme advantage of conversation between individuals on ship and shore, as compared with telegraphic communi- cation, must eventually overcome the difficulties which at present loom so Control panel of transatl;tntic telephone equipment at Rugby- large. 7

www.americanradiohistory.com Wilmhoo DECEMBER 12th, 1928. WopIlcol A Year's Progress in Commercial Wireless. - The main reason why short -wave communication is so The advantage of having wireless equipment in air- desirable is, of course, that for great distances short -wave craft has been made more apparent this last year working is much more economical than long -wave than ever before, for the simple reason that more working. aircraft have been flying. The disadvantages remain as before, weight and difficulty of operating, but it is The Cable-Radio Merger. only a matter of time before a way round is found and As regards telegraphy, short -wave services have de- it becomes acknowledged that wireless equipment is an veloped rapidly during the year. Many commercial ser- essential part of the machine. vices over great distances have sprung up all over the world, including a service opened last summer by the Post Office between this country and Kenya Colony. The amount of traffic sent over the short -wave tele- graph circuits between this country and Canada, Aus- tralia, South Africa and India has shown a steady in- crease. These circuits are worked by wireless telegraphy on the beam system. Hitherto they have been operated at this end by the Post Office, but other arrangements are now being made in accordance with the recommenda- tions of the Imperial Wireless and Cable Conference which met during the year. This conference, which was appointed by the Government, included representatives of Great Britain, the Dominions, the Irish Free State, and the colonies and protectorates. The conference recommended that a Communications Company be formed to take over all the communication assets of the cable companies and the Marconi companies concerned in exchange for shares, and to acquire the Government cables and the lease of the Post Office beam stations, the capital of the company not to exceed at its inception L30,000,000. The chairman and one other director are to be persons approved by the Government on the sug- gestion of the cable campanies, and British control of all the companies must be guaranteed. In addition, there is

High -speed signalling keys at the Northolt station. The new equipment at Croydon aerodrome has been brought into action during the year. The four trans- mitters are at Mitcham, a couple of miles distant, opera- tion and reception being carried out at the aerodrome at Croydon. Directional apparatus is fitted, and the process of finding the position of an aircraft takes less than a minute. Simultaneous bearings are taken from Croydon, Pulham, and Lympne, the intersection of the bearings giving the position of the machine in flight. Beam Telephone Possibilities. Developments in point -to -point wireless communica- tion have centred on short -wave working, but very few long-range commercial services are yet in operation so Eight hundred feet up. The top of one of Rugby's masts. far as telephony is concerned. The most notable of these telephone services is that opened by the Post Office to be an advisory committee, including representatives last summer between this country and America, as an of the Governments concerned, which must be consulted auxiliary to the long-wave service which has been in on questions of policy, including any alteration of rates. operation for some time. The external telephone services of Great Britain are, There is no doubt, however, that we are on the eve of however, to be left in the hands of the Post Office, which full commercial application of short -wave telephony for will come to terms with the company regarding the right communication over great distances, but 1928 cannot to use the company's wireless stations for telephone he registered as the year when this result was achieved. purposes. s

www.americanradiohistory.com .. l iv ... . a . . . _ _ .. - ç F- ' ...... , .. - . ,i .,...... +-g4.t -. .1'... , . DECEMBER 12th, 1928. WAp®Il®00 805 WOpIlCI

By Our Special Correspondent. Relays from Belgium. -How Ireland Fares. -New Year's Eve. -More Worry for Daventry?- B.B.C. and Variety Artistes. -- Christmas in Aberdeen.

Landline Triumph. just the qualities that count -if heard Belfast has the bravery to include a To the Post Office, as much as to the at the end of a long landline, however London symphony concert in its pro- B.B.C., belongs the credit for the really good that line may be. gramme. Hope springs eternal. AI- excellent relay from the Aberdeen studio 0000 though the submarine cable was con- on Monday, December 3rd. Those of us Belfast's Submarine Cable structed for speech only, the prayer ap- in London who may have switched on in When a submarine cable steps into the parently goes up that it will cope with the middle of the concert might have been picture the reproduction of music suffers strings, brass, wood wind and drums, forgiven for imagining, at first, that the still more. Anyone who doubts this " just for this once." performance was being given at 2L0. It is an open secret that of 0000 might ask the opinion of a Belfast lis- several these tener. (If he puts safety first, it would efforts have finished up via wireless from Daventry. 600 Miles. be better not to !) From time to time Naturally there were bad patches, but, 0000 considering that the landline was nearly B.B.C. and the Irish Free State. 600 miles in length, we should have for- FUTURE FEATURES. Dublin (2RN). the I.F.S. station, has given the Post Office if distortion had London and Daventry. been working quite a lot recently in asso- been far more marked. DECEMBER 18TH. -Nativity Play, relayed ciatioa with the B.B.C., relaying items from St. B. ilary's Church, Marazion, In a relay from Aberdeen the lines pro- Cornwall, S.B. from Plymouth. from Belfast. I hear that the station ceed first to Edinburgh, then to Leeds, DECEMBER 10TH. -" The Blue Forest " has been given practically carte blanche on to Manchester, and thence to London. (Aubert) a fairy opera. in the use of Belfast's material, but has 0000 DECEMBER 21ST. -" Alice," a play by not C. A. Lewis. made full use of the opportunity. A Belgian Proposal. DECEMBER 22ND.- Carols by the Civil One reason is that the Belfast evening The landlines in Belgium, particularly Service Choir. programme opens at 7.45, whereas Dublin Brussels, Daventry Exp. (5GB). does not generally begin its main pro- those radiating from have been DECEMBER 18TH. -Further Fireside Sing- immensely improved of late, which is one ing. gramme till 8 o'clock. The way out of this difficulty seems reason why the Belgian broadcasting DECEMBER 21ST.- Excerpts from Gounod's 0000fairly obvious. authorities have proposed a new series of " Faust." DECEMBER 22ND. -" Moonshine," a radio relays to this country, beginning possibly show written and arranged by On New Year's Eve. with the performances of the Vienna Charles Brewer. Sketches by Edwin Nothing revolutionary has yet been de- Lewis. Philharmonic Orchestra. The proposal is Cardiff. cided upon for ushering in 1929. Accord -, that this world- famous orchestra should DECEMBER 18TH.-Roads Through Song - ing to present arrangements, an item en- visit Brussels for a week and that the land, and Songs Heard by the Way. titled " 1928 -1929 " will occur in.14. pro- be DECEMBER 20TÁ.-" The Lord's Poor gramme 11.50 concerts should relayed to British, Brother," a play by W. Riley. at p.m. on December 31st, German and Dutch stations, which would DECEMBER 2250. -A Christmas Carol but at the time of writing the precise thus share in the enormous expense. I Concert. nature of the item is a mystery. hear it is this part of the proposition Manchester. 0000 that DECEMBER 16TH.-Bells and Service from which has provoked controversy at Savoy Chester Cathedral, with an address A Coincidence. Hill. by the Rt. Rev. Henry Luke Paget view of 0000 (Lord Bishop of Chester). In B.B.C.'s forthcoming move DECEMBER 18TH. -" Can You Guess These from Savoy Hill, 5GB's Christmas panto- Counting the Cost. Tunes? " mime, which is to be broadcast on No one doubts that the landlines could DECEMBER 22ND. -An Irish Programme. December 29th, provides a singular coin- give a fairly good account of the Vienna Newcastle. cidence. The titling was DECEMBER 17TH.-" Fair Game," a topical arranged some orchestra's performance; the question is revue by E. A. Bryan. weeks ago, and entirely without knows mainly one of cash. Is it worth while to Glasgow. ledge of the statement about the move. pay several hundred pounds for an orches- DECEMBER 21sT.- Scottish Community It is " The House the B.B.C. Built." tral performance of an hour or two, Singing Concert. 0000 which, to be brutally frank, could hardly Aberdeen. More Trouble for 5XX. DECEMBER 17TH. -" Impertinent Waves." be more satisfying than a British orches- presented by the Radio Concert As if Kalundborg and Lahti were not tra at the Queen's Hall connected to Party. enough, poor old Daventry (5XX) is Savoy Hill by a negligible amount of Belfast. threatened with another noisy neighbour DECEMBER 17TH. -An Ulster Ceilidh. landline? DECEMBER 21sT. -Christmas Concert of -no less a personage than Eiffel Tower The best orchestra in the world will the Belfast Philharmonic Society. himself. On January 1st Eiffel Tower suffer a loss of tone and distinctiveness - is to abandon the present 2,650 -metre B 35

www.americanradiohistory.com 8o6 71pishoo DECEMBER 12th, 1928. /nor?IlA wavelength and drop down to something been due solely to the microphone. tided that wireless services are good for in the region of 1,500. If the power Whether or not this is so, the General the soul and that the loud speakers must were to be normal, Daventiy might still Theatres Corporation are continuing to be retained. '1 his is at St. Peter's Church, hope for immunity from interference (at grant broadcasting facilities, and there Middlesbrough, where the wireless re- least on reasonably selective receivers) ; are grounds for the belief that other ceiver is used regularly on Thursday but the persistent rumours that Eiffel theatrical Organisations are showing .in- afternoons to pick, up evensong from Tower will employ 100 kilowatts puts a terest in the experiment. Westminster Abbey. The congregation different complexion on the matter. 0000 participates in the service, kneeling Fortunately the power increase is likely What the Theatres Gain. during prayers, following the lessons in to be deferred for a time. 511 is now the programmes of the variety theatres the Bib:es and singing the hymns. working on 1,562.5 metres. are peculiarly suitable for broadcasting. The vicar, the Rev. L. H. B. Stavely, One who has watched Daventry's Out of a total of fifteen or sixteen items a wireless enthusiast of twenty years' affairs during the last few months sug- constituting one entertainment it is standing, has a radio workshop that gests that the station's motto might be : nearly always possible to select one turn, strikes awe into the most hardened ' No one knows the trouble I've seen." usually vocal or instrumental, which the parishioner. 0 0 0 0 broadcast listener can enjoy without be- 0000 614 Boy Singers. ing tantalised by his lack of sight. At A Versatile Playwright. The microphone will be severely tested the same time one turn forms such a When Mr. ,John Drink water, the on Sunday next, December 16th, when small proportion of the entire bill that author of " Abraham Lincoln,' the broad- 614 boys of Ound'.e School, Northamp- the theatres sacrifice nothing in view of casts on December 18th from 2L0, he tonshire, will sing the chorus parts of the publicity gained and the soin paid by will not deal with any Bach's of those subjects " Christmas Oratorio," to be the B.B.C. which the listener might be inclined to broadcast from 5GB. The soloists will 0000 link up with his name, playwriting, for be Carrie Tubb, Margaret Balfour, John Long Contracts. example. He will talk about stamp Adams and Topliss Green. 1 here is now under consideration a collect ing. 0000 scheme which may possibly overcome one 0000 Personaba. of the biggest obstacles to a rnpprodie- The Music of Finland. Mr. 1). ( leghorn Thomson. the irrrat between the B.B.C. and the Finland is providing the next of the Regional Director for Scottish broad- theatres. The idea is for the B.B.C. to " National Programmes,'.' casting, whose on Thursday, engagement was an- engage variety artistes on long contracts December 20th, from 2L0. Although the nounced a few days ago, is still on the to prepare and perform original material country is litt e known to Britons, it has glorious side of thirty, while his fiancée, exclusively for the microphone. Too given the world such eminent musicians Miss Virginia Fain, is still at college at often in the past a variety artiste has as Sibelius and Palmgren. Brinmawr. Mr. (' leghorn Thomson's been tempted to dip into his stage reper- 0 0 0 0 association with broadcasting dates from toire for broadcasting purposes, to find Christmas Day at Aberdeen. 1925, when he came to Savoy Hill after later, to his dismay, that the same jokes The " fireside " aspect Christmas being defeated of at South Edinburgh in fell flat when re- hatched in the theatre. will be represented in the third part of the General Election of 1924, in which lie A happy ending may still be in sight the very well -balanced Christmas pro- was the youngest 0000Liberal candidate. if theatrical managers can be persuaded gramme which Scottish listeners will hear that broadcasting is not another -name for on Christmas Day. This part of the Proadcasting and the Theatres. poaching. programme will come front Aberdeen, Contrary to 0 0 o o the opinions expressed by and wi'l consist of one of those " fea- many of the Grand Moguls in the Wireless Services in Church. ture " Scottish programmes theatrical in which the business, the broadcasts front The congregation of at least one Northern station has always been par- the Palladium have had no harmful effects church, having heard Archbishop David - ticularly successful. Its title, " Farmer on the box -office receipts; indeed, there is son's farewell sermon from loud speakers Mowat's Christmas at the Mains o' a suspicion that a slight upward fillip has in their own place of worship, have de Urnmspeffer," conveys its character.

A MODERN BROADCAST TRANSMITTER. The time has long passed when the mere mention of wireless conjured up visions of wire entanglements and very vulnerable apparatus. The robust nature of moiern equipment is well illustrated in this photograph, which shows the new transmitter constructed by the Marconi Company for the broadcasting station at Bratislava, Czecho -Slavakia. It will supply the aerial with 12 kW. A description of the apparatus appears on page 796. B 36

www.americanradiohistory.com DECEMBER 12th, r28. WpYd@mo 807 7orcIl1

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The Service is subject to the rules of A selection of queries of general the Department, which are printed interest is dealt with below, in some below; these must be strictly enforced, cases at greater length than would be in the interest of readers themselves. possible in a letter.

"r The Wireless World " Supplies a Free Service of Technical Information.

Push-pull or Parallel ? that the D.C. resistance of the choke H.F Transformers for A.C. Valves Would ?¡-a recommend nee to use a pair should be comparatively low. We can- From statements published in your of pentode valves in parallel instead not snake helpful suggestions as to the journal, I gather that it i"s necessary of the single output valve specified best value for its inductance, as this to remove some two or three turns in the description of the " Hilo -Mag depends on the impedance of the loud from the primary and neutralising Four" receiver? My desire is to get speaker windings, etc., and is best found windings of standard " Everyman a larger output combined with by trial. Four " transformers when they are greater L.F. magnification. 0000 used with indirectly heated A.C. R. de G. M. A Reaction Failure. valves. Prom which end of the Pentode valves are not at their best Some time ago a statement appeared in winding should these turns be taken when following an anode bend detector "'l'he Wireless World " to the effect off ? P. T. C. with transformer coupling, and your pro- that an " crneriodic " aerial tvindiuq Referring to the primary winding, the posed scheme is not altogether to be re- could be made to serre the dual par - turns should be taken off from the end pose of a roil. commended. However, there is a way reaction I hare tried which connects to plate of the preceding. the difficulty, and we suggest that this arrangement with an " Every - valve ; similarly, the neutralising section out of man aerial -grid transformer, you use two pentode valves in a push -pull Four" should be reduced from the end joined to arrangement. By adopting this plan, the connected up in the manner shown in H.T. +. These are the ends of the the diagram am sending you, L.F. voltage from the detector will be which. I parallel superimposed windings which are between their two but hare failed to obtain reaction nearest to the " grid " end of the equally distributed effects; the set works better secondary. grid circuits. indeed, 0000 0000 with the reaction condenser dis- connected. Is my diagram correct, or The Earth System. A Tone -raising Device. doe, this simple arrangement only There seems to be some uncertainty as to The tone of my loud speaker is satisfac- apply to some special circuit? which type of earth connection is tory enough, but is rather lacking in J. S. best. Do you prefer a junction to a brilliance. Is it possible to improve Your circuit (reproduced in Fig. l) is waterpipe or to a buried plate? in this respect by connecting matters correct ; but we think that the trouble is P. C. C. an L.F. choke in series with it? clue to the fact that the aerial- reaction It is impossible to make a definite J. L. statement, as a good deal depends on cir- No; your proposed alteration will have cumstances. Provided that a reasonably the opposite effect to that which you short and direct lead can be taken to a desire, but it is possible to reduce the " rising " water main, it is likely to be response at low frequencies without better than the average buried earth materially altering the reproduction of plate, etc., which is seldom of sufficiently higher tones by connecting the choke in large dimensions for maximum effective- parallel with the loud speaker windings. ness. To get well -defined results it is necessary 0000 Quality Reception.- - ll'hat modification would you suggest RULES. in the L.P. amplifier of the " Eurepa (1.) Only one question (uhic1e must deal with a single specific point) can be answered. Letters II! " in order to render it .specially must be concisely worded and headed " Infor- suitable for operating a moving coil motion Department." loud speaker? S. M: D. (2.) Queries mast be written on one side of the paper, and diagrams drawn on a separate Your query is best considered withopi sheet. .4 self- addressed stamped envelope mast particular reference to the Europa III, be enclosed for postal reply. but to circuit systems essentially suited for (3.) Designs or circuit diagrams for complete receirers cannot be given ; under present-day moving coil loud speaker use in general. conditions justice cannot done to questions Neither leaky grid detection nor reaction of this kind in the course of a letter. should be employed in this instance. (4.) Practical wiring plans cannot be supplied or considered. For complete details of a suitable circuit (5.) Designs for components such as L.F. Fig. 1.- Simple reaction circuit with com- system you are referred to the construc- bined aerial and feed -back coil. The two chokes, power transformers, etc., cannot be tional booklet obtainable from pub- supplied. windings must be in opposite directions. the (6.) Queries arising front the construction or lishers, " The Moving Coil Loud operation of receivers must be confined to con- winding L is not in the correct sense Speaker " (price ls. 6d., post free structional sets described in " The Wireless World " or to standard rnanufacturers' receivers. with respect to the secondary L,. To ls. 8d.). It is good advice to use ampli. Readers desiring information on 'matters use one of these coupling transformers fiers of low stage gain and practically beyond the scope of the Information Depart- for your special purpose it is necessary restrict your moving coil loud speaker ment are invited to submit suggestions regarding subjects to be treated in future articles or that the two windings should be put ou reception to the local station. The paragra plis. in opposite directions. Europa III is a good long -range set. B 37

www.americanradiohistory.com 8o8 Wfipesoo DECEMBER 12th, 1928. WoIld Fitting a Pentode. ternal connections are indicated by the from the fact that it is also more sensi- Would it be in order to fit a pentode conventional lettering : P, plate; B, H.T. tive to considerable inputs. If a detector valve to the "Everyman Three" re- positive ; G, grid ; F, filament. of this kind is followed by two high - ceiver, and, if so, what alteration 0000 magnification L.F. stages, it is now would be necessary? H. S. Sets for Abroad. widely appreciated that any H.F. input As this receiver has but one trans- Will you make a suggestion as to the most sufficiently_ great , to give good detection former-coupled L.F. stage, it would be suitable type of circuit for a receiver will badly overload a normal output valve, quite possible to substitute a pentode for which I propose to take out to the even if the H.T. voltage applied to its the normal output valve. The coupling Soudan? I should like to be able to anode is somewhat above the average. It between H.F. valve and detector is by receive both the broadcast wave- will therefore be obvious that for good means of a transformer, so no special bands, and imagine that three valves quality reproduction it will often be modifications would be necessary, beyond would be su;icient, as loud speaker necessary to reduce L.F. amplification; adding the usual connections between the reproduction would not be required. it is not a bad plan to have this amplifi- pentode screened grid terminal and the cation under control so that the user _can H.T. battery. I suppose that two H.P. stages would be essential for such long -distance re- take advantage of maximum sensitivity 0000 ception? C. M. T. for long -distance reception when it is desired. Transformer Coupling with S.G. Valves. We hardly agree that two H.F. valves 0000 Is it possible to use the type of trans- would be necessary or desirable. At very former described for the " Kilo -Mag. great distances, where one depends en- Low-loss Superfluous. Four" receiver in a set with a single tirely on " freak " reception on the nor- My Det. -L.P. receiver, of which I am stage of H.P., a leaky grid detector, mal -wavebands, ease of operation and sending you a circuit diagram, is and reaction? If so, will you tell me facilities for rapid " searching " are more fitted with commercial plug-in coils; haw a reaction winding may be important than the utmost possible degree would it be worth while replacing added? B. R. B. of magnification. A good H.F.- det. -L.F. them with single -layer Lit_ windings, The transformers in question lend them- combination with an S.G. H.F. valve and and would this substitution gire snore selves quite well to use in a circuit such reaction should meet your needs as well .signal strength and selectivity? as you describe, and a reaction winding as anything else. May we suggest, how- F. A. The commercial coils you are using are quite good, particularly when their ex- treme compactness is taken into con- F B -4- H.T REACTION sideration. In any case, in a circuit WINDING such .as you show, where the grid coil to or= is damped by connection to the aerial 0000000 and also by leaky grid condenser detec- o000000l SEC . tion, it is quite useless to reduce coil 0000000 resistance beyond a certain point, and /////////r we hardly recommend you to make a change. 0000

FORMER Points of Criticism. Will you please criticise the diagram, of my proposed receiver, bearing in mind the fact that I ant hoping for good -quality reproduction combined REACTION with the maximum possible range - WINDING G- 0000oq 9000008 getting properties, and a high de- 0000ooF gree of selectivity. T. P. A. w Your circuit diagram shows a screened PRIMARY grid H.F. amplifier with tuned H.F. transformer and a loosely coupled and (a) (b) separately tuned aerial circuit, followed by an anode bend detector. Up to this point we have nothing but favourable Fig. 2.- Sectional sketch of an H.F. transformer for S.G. valves, with added reaction to offer, winding. Its connections are shown in the circuit diagram. criticism but with regard to the L.F. amplifier, which consists of two transformer- coupled stages of high mag- can very conveniently be added in the ever, that you would probably be well ad- nification, we think that some alteration MI-liner shown in Fig. 2 (br: It should vised to concentrate entirely on the ultra= will be desirable. You show no form of be in the form of a compact " bunched " short wavelengths, to the exclusion of the volume control other than that afforded winding consisting of from 15 to 30 normal broadcast bands? by the H.F. valve rheostat, and it will turns (depending on the capacity of the 0000 be found that any signal voltage suffi- reaction condenser) of No. 40 D.S.C. ciently great to give good rectification wire, wound on an extension of the A Low -magnification Stage. with your anode. bend detector will un- spacing strips which separate primary I have read that in cases where an anode v- doubtedly overload the output valve and secondary, and spaced about bin. bend detector is followed by two L.F. with an applied H.T. voltage as indi- stages, may sometimes be desirable from the other windings. For the long - it cated in your diagram. wave transformer, the reaction winding to sacrifice amplification in the first The remedy would be to fit a control of should be added in a similar manner, stage by using a low value of anode the signal voltages delivered to the first but 70 or more turns will be necessary. resistance. Why is this? .Surely it L.F. grid. This might take the form of The connections may be as in Fig. 2 would be possible to reduce the input a variable resistance across the first (a); by adopting this arrangement the to the detector to a suitable value, transformer primary. Alternatively, yoù- number of external leads to the trans- and to avoid any sacrifice of L.P. could use grid rectification, but this former is kept down to five, but if you magi.i/ication? T. L. W. would imply the addition of reaction, wish to keep one side of the reaction The important point here is that an which would tend to complicate matters. control condenser at low potential it is, anode bend detector gives more perfect Again, it would be possible to substitute of course, necessary to bring out a second rectification from the point of view of a resistance coupling of low -or, at any connection from the reaction coil. quality when the H.F. voltage applied to rate, controllable-magnification in the Referring again to diagram (b), ex- its grid circuit is large ; this is apart first stage. B 33

www.americanradiohistory.com he rele AN D RADIO REVIEW (161h Year of Publication)

WEDNESDAY, DECEMBER 19TH, I928. VOL. XXIII. No. 25.

given equal prominence and the programmes day Editor: HUGH S. POCOCK. after day are treated in the same way, that they are of neces- Assistant Editor: F. H. HAYNES. sity all of equal merit. If the B.B.C. took steps to adver- Editorial Offices: 116 -x17, FLEET STREET, LONDON, E.C.4 tise extensively a forthcoming programme of particular Editorial Telephone: City 9472 (5 lines). character is it not likely that this would result in a great Advertising and Publishing Offices: extension of the listening audience on that particular DORSET HOUSE, TUDOR STREET, LONDON, E.C.4. night, and would, in many instances, serve to Telephone: City 2847 (13 line;). Telegrams: Ethaworld, Fleet, London." revive interest in broadcasting amongst those on whom it may COVENTRY : Hertford Street. Trlryrein +: "lyrliat. L'oventry.' Telephowe: 6210 Coventry. be beginning to lose its hold?

BIRMINGHAM : Guildhall Buildings, Navigation Street. Telegrams: Ao.opre+± Birmingham:' Telephone : 2970 and 2'J71 Midland. The Effect of Advertising.

MANCHESTER : 260. Deansgate. The public more and more requires to be reminded of Mears.. "Iliac. Manchester." Tdrphone: 8970 City (4 Meet. PUBLISHED WEEKLY. forthcoming events through the medium of bold adver- Subscription Rates : Home, ils. 4d. ; Canada, 17s. 4d. ; tising, and whilst it might be argued that the immediate other countries abroad, 195. 6d. per annum. effect to the B.B.C. and to broadcasting generally of in- Entered a second Class Matter at New York. N.Y. creasing the number of listeners on any particular night As many of the cirer,!, and apparatus descrihed in these pages are roicred by Dolents, readers arc advised, before making use of than, to satisfy themselves by, say, 5o per cent. would be imperceptible, yet we can- that they mould not be infringuig patents. not believe that the achievement of such a result, which could certainly be done through the medium of adver- CONTENTS OF THIS ISSUE. PAGE tising, would be devoid of beneficial consequences to the 809 cause of broadcasting generally, provided the pro- HIGH FREt.,FNCI RESISTANCE. BY A. L. M. 'Os rosy 810 DRY CELL H.T. BATTERIES. BY K. W. W. SANDERSON 815 grammes so advertised were of a high standard -a con- CURRENT TOPICS ...... 818 PROGRAMMES FROM ABROAD ...... 820 dition which is, of course, obviously necessary what- THEORY OF THE METAL RECTIFIER 8.24 ever may be the subject of advertisement. MEGAVOC EI.IMINATc,R (CONCLUDED). BY W. I. G. PAGE 827 0000 BRccAI,cAsr BREVITIES .. .. 832 LSFF CI. DATA CHARTS : No. 19, STAG I .. .. 831 NEw APPARATUS ...... 838 HOLLAND'S NEW EXAMPLE. LETTERS TO THE EDITOR ...... 838 KF.t DER; PROnL:ìMS ...... 840 1- UST as Holland was the first European country to establish a short -wave broadcasting station with a SHOULD THE B.B.C. ADVERTISE THE world -wide range which enabled her to communi- PROGRAMMES ? cate direct with her colonies, so again Holland has taken T is interesting to cgqpptemplate what proportion of the the lead by arranging that the famous station PCJJ, owners of broadcást receivers listen to the pro- now at Hilversum, shall transmit on a weekly schedule i grammes regularly. It has become the fashion to with times and languages so arranged that far -distant own a wireless set, and the home is scarcely regarded as countries will be able to listen to transmissions by the complete without one, but how often is it used? There station in their own tongue at times most favourable for are, of course, some devotees of listening -in who prob- reception. ably never lose an opportunity of switching on the set if We have previously urged that the time has come they can possibly avoid it, but there must be thousands when our short-wave transmitter, 5SW, should cease to of others who only listen occasionally and who do so be regarded as an initial experiment only, and should less and less for the reason that the bulk of the pro- be established on a permanent basis and conduct trans- gramme matter has little or no appeal to them. missions at intervals throughout the twenty -four hours so that reception in various parts of the British Empire A B.B.C. Obligation. may be made possible at s'titable times for reception. It is the business of the B.B.C. to popularise broad- If there is no intention of establishing 5SW on a per- casting and to induce the public to form the habit of manent basis, then it wculd seem to us that what time constant listening, but in these days of continual activity and money has already been spent on the station has few of us can be systematic about our hours of leisure been wasted effort ; if, on the other hand, it has been and consequently do not search through the programmes intended since the start that eventually 5SW should be- from day to day to ascertain what items are likely to he come a permanent service station, then surely the time of special interest to us. There is also, perhaps, the feel- is long overdue when this change of status should come ing that since in the published programmes all items are about. 19

www.americanradiohistory.com 8io WfiP@Il@og MAO DECEMBER 191`i, 1928,

What It Is and Whence It Comes. By A. L. M. SOWERBY, M.Sc.

THERE has been in the past much argument and high- frequency resistance. The results of the tests were discussion on the subject of high- frequency re- published in The Wireless Wòrld, and a large amount of sistance, especially in connection with the tuning practical information on the subject of coil design was in coi s used in wireless reception, and a vast amount of this way made public for the first time, but the informa- energy and enthusiasm has been expended in winding tion was difficult to apply owing to the fact that the basic coils of all types, shapes, and sizes in the endeavour to principles underlying the whole matter had not then been find a means of keeping the resistance down to a mini- made public. mum. A month or two later there began in Experimental Interest in the subject was kept fully alive till about Wireless a series of articles by S. Butterworth; in which two years ago, because up to that time no one, whether the result of his mathematical researches was fully pre- radio engineer, pure scientist, or set constructor, could sented (Experimental Wireless, April, May, July, and formulate any rules that would enable him to decide August, 1926) for the first time ; the publication of these definitely how to wind a coil giving the lowest attain- articles was possibly hastened by the competition, as it able high- frequency resistance. The only known way provided a wealth of experimental data to confirm the of finding how best to wind a coil was to adopt the " hit purely mathematical deductions. This series was finally or miss " method of making up a number of coils, summarised in a couple of articles of practical type which measuring their high- frequency resistance, and choosing appeared in these pages (The Wireless World, December for incorporation in the receiver that coil for which the 8th and 15th, 1926) giving the fullest instructions, with lowest value had been found experimentally. Such a curves and tables, for calculating the best dimensions, process is intolerably tedious, calls for laboratory ap- the best gauge of wire, and the best spacing to give the paratus, and is intellectually unsatisfying. lowest possible high- frequency resistance for coils of any given The Wireless World Coil Tests. bulk. Alternatively, the high -frequency resistance of any coil of which the dimensions were known could By the middle of 1925 a physicist, S. Butterworth, be calculated. had worked out in detail a means of calculating the high - frequency resistance due to the wire of which a coil was The Advent of the Screened Grid Valve. wound, and in July of that year he published an article The publication of these articles promptly put a stop to (Experimental Wireless, July, 1925, p. 613) in which all controversy on the subject of the high- frequency resist- the formula for calculation was given, though without ance of tuning coils, for here was the information necessary the tables of constants that are necessary for the full to calculate the answer to practically any problem application of the formula. In the article he applied that might arise, the sole mathematical equipment neces- his formula to a coil of which experimental measure- sary for the user of the formula being a slide-rule or a ments had been made by another writer, and showed table of logarithms in order to shorten an otherwise that the agreement between experimental and calculated tedious series of arithmetical operations. - results was very close. The cessation of interest in high- frequency resistance In November of that year The Wireless World inaugu- that was brought about in this way has resulted in the rated a competition in 'which readers were invited to almost complete neglect of this topic by writers on submit for measurement the best coil that they could wireless subjects, so that it is not .improbable make, and a prize was offered for that with the lowest that some who have only lately become addicted to

A 20-

www.americanradiohistory.com DECEMBER zgth, 1928. WArnhoo 8ii "oacl High Frequency Resistance - It is very well known, however, that this is not the wireless are not quite clear as to what this high- frequency only kind of obstruction offered by a coil of wire to resistance may be, and why there has been so much fuss the passage of an alternating or high- frequency current. about it in the past. A short discussion of it may, there- For example, that familiar component, the high -fre- fore, not be out of place at the present time, especially quency choke, permits the steady plate current to pass as the advent of the, as yet; imperfect screened valve with but little hindrance, while it is a very serious barrier must inevitably arouse fresh interest in the subject, indeed to the passage of high- frequency currents. In though from a different angle. such a case as that of Fig. i, where the alternative ` path As applied to tuning coils, the semi -slang term ' low - offered to them is a comparatively easy one, practically loss," which will be familiar to all through its wide use the whole of the high- frequency currents will pass by advertisers of components, is practically synonymous with " having a low high- frequency resistance." The only difference between the two ways of expressing the same idea is that in using the term " low -loss " it is generally implied that all possible sources of loss have been kept down to a minimum, especially losses due to the former upon which the coil is wound, and to the plug or method of connection employed. The statement that a coil_ has a low high- frequency resistance is usually taken, perhaps owing to the influence of the articles mentioned above, to refer more specifically to the losses due to the wire itself and to the method of winding, the influence of extraneous factors such as the former and the connections being ignored. Fig. 1. -The high -frequency choke in the above detector valve anode circuit does not absorb high -frequency energy but deflects The Origin of High-frequency resistance. it to earth through a comparatively low- resistance path C. of which the coil is wound there In the copper wire through the condenser C and so be deflected from the are several distinct sources of high- frequency resistance. L.F. amplifier. In the first place, there is the ordinary direct- current The reluctance of of a choke to pass high- frequency resistance of the wire ; that is to say, the absorption currents must not be looked upon, however, as from an ac- as being due power that occurs when a direct current, to the absorption of these currents, and their conversion for example, is sent through the coil. The cumulator, into heat by that component ; we have just and so dis- restated the power so absorbed is converted into heat well-known fact that, on the accumulator other hand, they are de- sipated, just as the power drawn from an flected through the condenser. heat up that filament. Why does the choke do by the filament of a valve serves to this? The question seems far enough from our subject, does not depend upon the frequency of the This loss but when it is answered we shall have arrived at a, very clear conception of the origin of high- frequency resist- ance. In passing through a coil of wire an electric current sets up a magnetic field -or, in other words, converts_ the coil into a magnet. Familiar examples of this are found in the electric bell, the " pot " of a moving -coil speaker, or the ordinary telephones. Now, a magnetic field, since it will cause pieces of iron (the armature of the bell, or the diäphragm of the telephones just men- tioned) to move about, must quite evidently possess a very appreciable amount of energy, and this energy it must derive from the current that brought it into exist- ence. That is one of the two fundamental properties of the magnetic field. The Function of a High-frequency Choke. The other is that this energy can be reconverted into an electric current, thus reversing the process already A typical coil submitted for ' The Wireless World" low-loss coil tests. The inductance was 102 microhenrys, and the coil was mentioned. It is of this fact that advantage is taken in wound with 42 turns of No. 16 D.C.C. The high -frequency resis- tance was 1.5 ohms. the transformer, where the energy of the varying mag- netic field set up by the alternating current in the primary current flowing, and is therefore the same whether is used to produce currents in the secondary. A more the current is direct or alternating, and may be looked homely., and perhaps more convincing, demonstration upon as a kind of frictional resistance that the current of the storing of energy in a magnetic field is found in meets in forcing its way through the wire. An analogy the fact that when the field current of a moving -coil may be found, though it is not a complete one, in the speaker is suddenly interrupted, and the magnetism of friction encountered by water in flowing through a pipe. the pot is no longer maintained by the current, a very A 21

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812 Wfipas@g5 DECEMBER 19th, 1928. IiopIld High Frequency Resistance. - practice, some energy is always lost by secondary effects vicious spark ensues. The very considerable energy of that we have still to take into account. It is these This spark is drawn from the powerful magnetic field of secondary effects that provide the high-frequency resist- the pot -magnet. ance, which is the title given to the sources of energy Applying these principles to our high- frequency choke loss in the coil. (and ignoring the steady plate current flowing through As already mentioned, we have first the direct -current it) we have only to remember that the chief feature of resistance of the coil, which absorbs a certain small an alternating or high- frequency current is that it is amount of energy. This is the only loss caused directly perpetually reversing its direction. As it begins to flow by the passage of the current itself. in one direction through the choke it sets up the in- evitable magnetic field, and as the energy of this has Losses Due to Eddy Currents. to come from the current the latter is considerably im- Other losses, and these peculiar to alternating or high - peded in its progress. By the time the current has frequency currents, can be caused by the fact that the reached its maximum value in one direction the mag- magnetic field is continually building up and then netic field has, of course, reached its maximum intensity. collapsing again. We have assumed that the whole of As the current tries to die away again in preparation for the energy of this field is returned to the coil when it starting to flow in the other direction it is again thwarted collapses, but it is evident that if any energy is by the magnetic field, which, in collapsing again, tends abstracted from it in any other way, this complete re- to keep the current flowing in its original direction. By fund of energy cannot occur. The only source of such the time the current has been permitted to die away abstraction of energy is to be expected in the setting up again completely the magnetic field has also gone. of currents other than that which we have already con- Exactly the same routine sidered. This can take place is gone through again as the if there is any piece of metal current flows in the other or other conducting material direction, the sole difference within the range of the mag- being that the reversal of the netic field ; in this case current implies also the re- " eddy currents " (which versal of the direction of the may be looked upon as aim- magnetic field. This whole less currents that go no- double process is gone where in particular and are through, if the set of Fig. i no use to anybody) are is tuned to 30o metres (1,000 set up or " induced " in the kilocycles), a million times metal. Since the material in every second. which they are set up has a The point to which it is direct - current resistance, desired to draw attention is these currents give rise to that the high- frequency cur- Fig. 2. -A simple circuit In wh Ich the secondary of an aerial heat, in transformer is connected to an anode bend detector valve. The and this way some rent has been checked in its rectified output to the low-freque ncy amplifier depends to a large of the energy of the mag- passage through the choke extent on the high- frequency r esistance of the tuned circuit. netic field is abstracted from by its interaction with the it, dissipated, and lost. magnetic field, and that at the end of the process, since This is, in fact, the source of the component of the total all the field built up at one instant has vanished again - losses that is peculiar to alternating or high- frequency has been converted back again into current-everything currents. is as it was before the process began, and no energy has At first sight, this source of loss seems easy enough been absorbed by the choke. to eliminate, by simply ensuring that there is no metal within the magnetic field of the coil. is The Tuning Coil. This an excel- lent idea, as far as it goes, and supplies the reason for It will no doubt be clear that the effects we have keeping metal screens in high- frequency amplifiers as described are in no way dependent for their existence, far from the coils as possible, but it is quite impossible but only for their magnitude, upon the number of to carry out this removal of metal entirely. There must turns in the choke. If the number of turns of the choke always remain the wire of which the coil itself is wound. were to be reduced from the 2,000 or so to perhaps 6o Thus, in addition to providing the " legitimate " cur- only, the production and disappearance of the magnetic rent that we have already, the magnetic field sets up in field would naturally still go on. But 6o turns, on a the wires of the coil eddy currents that circulate aim- rather larger former, makes not a choke (except for the lessly in small closed paths, and, encountering the resist- ultra -short waves) but our familiar friend the tuning coil, ance of the material of which the wire is composed, give so that we see that the passage of a high -frequency cur- rise to heat -losses over and above those that would be rent through a tuning coil is attended with precisely the caused by the passage of an ordinary direct current. same magnetic phenomena that we have been discussing. For convenience of calculation, those engaged in the We have said that no energy is absorbed by the study of this source of loss have divided these eddy choke -or, as we will now noncommittally call it, the currents into two classes, by taking each turn of the coil-owing to the production and disappearance of the coil, instead of the coil as a whole, as the unit. On magnetic field. This is true in the ideal case only ; in this basis, we think of the magnetic field as the sum A 22

www.americanradiohistory.com DECEMBER igth, 1928. WpGIlC7@o 813 W O 11 High Frequency Resistance.- This very brief analysis of the constituent parts of the of all the fields set up by the separate turns, and then, losses in a coil has so far only taken account of those regarding the field of a single turn, we observe that the losses due to the wire of which the coil is wound, and eddy currents to which it gives rise are partly in itself has omitted altogether to consider the possibility of and partly in neighbouring turns. absorption of energy by the former, or by other parts of the The Skin Effect. tuned circuit. These losses are by no means negli- gible, as will be shown, though in the coil itself they The eddy currents which each turn induces in itself, result in augmenting its resistance by only some 15 per since they are perfectly independent of neighbouring cent. They are, unfortunately, not calculable, and turns, will remain the same whether the turn that we introduce into receiver design a source of uncertainty choose to consider is in the middle of the coil, with other which is too large to be neglected. turns on both sides of it, or at one end, when it will Before attempting to consider these other sources of have other turns only on one side ; they will even re- loss, let us turn our attention, now that high- frequency main almost unchanged if we undo the turn in question resistance has become a fairly familiar conception, to its and stretch the wire out straight. The direction of flow effects in a tined circuit. We shall then see why the of these eddy currents is such as to neutralise some of desire for low resistance has arisen, and the need for it the original current at the centre of the wire, and to in á practical receiver. augment it at the surface, so that the net result is as The simplest form of receiver, so far at least as the though the original current had been forced to flow high -frequency side of it is concerned, is shown in mainly on the surface of the Fig. 2. It consists of a wire instead of being, as single tuned circuit, fed one would find if this effect from an aerial with the were non -existent, equally high- frequency voltage de- distributed throughout the rived from, let us say, the whole wire. In consequence local station at fairly close of this, the phenomenon we range. Across the circuit is are discussing is generally connected an anode recti- called the " skin effect," fier, this type being chosen under which title it will be because we can assume, to known, at least by name, to a first approximation, that most readers. The numeri- adding it to the tuned cir- cal value of the extra resist- cuit makes no difference to ance introduced by thus it in any way, for it re- forcing the current to utilise quires no power to operate a portion only of the wire it. has long been calculable Disregarding entirely the with exactness. mathematics of the circuit, The other part of the which is outside our present eddy current losses, due to scope, we can nevertheless the currents induced by the arrive quite easily at the turn we are considering in exact effects of This coil won second place in "The Wireless World low-loss high -fre- those near it, must clearly coil tests in February, 1926. Although wound with 38 turns of quency resistance. A glance bare No. 19 gauge wire, the high-frequency resistance at 400 depend on the distance be- metres was 3.0 ohms. at the circuit shows that the tween turns, the total num- detecting valve is connected ber of turns, the shape of the coil, and the position of across the tuning condenser C, so that the voltage we our turn relative to the others ; in other words, upon the have to operate the detector is simply the voltage de- exact manner in which the wire is coiled up. It is this veloped across this condenser. It is clear enough that portion of the total losses, which is a very high one, the greater this voltage can be made the louder will be that made it impossible until recently to calculate the the signals that we shall get, for they depend upon no high -frequency resistance of a coiled wire, and drove other factor than the high- frequency voltage applied to coil -users to the " hit or miss " methods of coil- design the detector. to which reference has already been made. If refer- ence is made to the articles mentioned, dealing Signal Strength and H.F. Losses. with the calculation of the high- frequency resistance of Just as in the case of an ordinary direct current cir- a coil, it will be found that all three losses are included cuit, where the magnitude of the voltage -drop across a in the calculation, and that, although they are all dealt resistance depends entirely upon the current flowing with in the same formula, this contains two terms to through it (see Fig. 3), the voltage -drop that works our deal with the " skin effect " and the losses due to coil- detector depends directly upon the high-frequency cur- ing the wire respectively, while the fact that all three rent that i>; flowing through the condenser C. If this is losses represent, in the end, dissipation of heat through large, the voltage will also be large ; if the current is the direct current resistance of the wire is expressed by small, so will be the voltage. Since, in a practical the fact that this occurs as a multiplier to the whole case, the size of the condenser is fixed by the necessities expression. of tuning, we have no option but to make the outrent A 23

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Vpdsmai DECEMBER 19th, 1928. WOpIld High Frequency Resistance. - doubling of input voltage with a fourfold increase in flowing in the circuit as large as possible if we want to signal strength. get the loudest signals. The voltage supplied by the This, then, is the reason why the subject of high -fre- aerial is more or less fixed, so that the only control we quency resistance has received so much attention in the have over the current in the tuned circuit is obtained past, for every lowering of resistance results in an in- by alterations of its high- frequency resistance, and, to crease of signal strength. Where there are several tuned get a large current, it is evident that this must be made circuits in the receiver, as, for instance, in sets employ- as small as possible. ing high- frequency amplifiers, the benefits obtained by attention to this point are even greater, for the effect is cumulative from stage to stage. We have so far discussed the sources of energy loss in a coil alone, considered as an isolated component, and we have seen both that it is desirable to keep these losses down to a low figure for the sake of efficiency, and that they can be calculated with reasonable accuracy for the purposes of receiver design. It must not be for- gotten, however, that the coil is only part of the tuned circuit, and that set design is based on the characteristics of the tuned circuit as a whole, and not on those of the Fig. 3.-(a) An ordinary direct current circuit where the magnitude condenser, of the voltage drop across a resistance depenus entirely upon coil alone. The various components-tuning the current flowing through it. Voltage drop equals resistance valve -holder, grid leak, and so forth -that are connected multiplied by current, or E =IR. (b) current through C at any frequency equals voltage drop across C divided by Z, the im- to the coil in a completed amplifier give rise to further pedance of C: (f=!). Hence voltage drop equals impedance losses, of a type quite different in their origin to the multiplied by current, or E =IZ. losses we have been considering. These other sources of loss are equivalent in their effects to an increase of We can safely carry the analogy with the direct cur- the high- frequency resistance of the coil, and must there- rent circuit a stage farther ; in both cases halving the fore be taken into account when designing an amplifier. resistance will result in doubling the current, and, there- Although these incidental losses cannot, so far as the fore, in our receiver, in doubling the voltage applied to writer knows, be calculated with an exactitude, they can the detector. The fact that we are using an anode de- at least be measured, and some measurements of them, tector is an additional inducement to do all we can in together with an account of the way in which they arise, this direction, for this type of detector responds to .a will be given in the second part of this article. (To be concluded.) INVENTIONS OF WIRELESS INTEREST. The following abstracts are prepared, with the permission of the Controller of H.M. Stationery Office, from Specifications obtainable at the Patent Office, 25, Southampton Buildings, London, W.C.2, price is. each. Loud Speakers. carries the actuating winding or speech in order to balance the effect of the (No. 288,386.) coil W. grid -filament capacity C2, which shunts Application date : January 19th, 1927. The sound -box S is slotted centrally, the coil L. Actually the capacitance N The diaphragm D, Fig. (a), consists of and is preferably mounted inside a double takes the form of an external cylinder a band -shaped member which is housed horn of the shape shown in Fig. (b), so K (Fig. b) closely surrounding the glass inside an elongated sound -box S and sup- that sound waves emitted from the upper opening of the slot are deflected by a central rib on the outer horn, whilst waves coming from the lower opening are fed directly into the inner horn. Patent issued to H. Sachs. o o o c Stabilised H.F. Amplification. (No. 283,497.) Convention date (U.S.A.): January 11th, 1927. Relates to an improved method of stabilising a H.F. amplifier so as to Neutralising the grid filament capacity secure accurate symmetry. The dotted - of a valve. (No. 283,497) line condensers CI, C2, C3 in Fig. (a) A double -horn loui speaker with centrally makes slotted sound -box. (No. 288,386.) indicate the several inter -electrode valve bulb of the valve. The cylinder capacities in operation. The ordinary a sliding fit on the bulb, so that its ported at two points, B and B,. The neutralising condenser, inserted in series effective capacity, represented by the con - upper support B is a point bearing, whilst with the plate electrode and a split in- denser N in Fig. (a) can be readily ad- the lower B, is designed to allow of a put L,' Li, is shown at N. In practice, justed as to the required value. In these slight longitudinal movement. A part of however, the capacity C2 between the circumstances the plate of the valve the diaphragm extending outside the grid and filament tends to upset the forms a common capacity surface be- sound -box projects.into the magnetic field balance at high frequencies. tween the condensers C and N. between two pole pieces, l', P,. Otte Accordingly, an extra condenser Ni Patent issued to The Marconi Co., pole piece P.is thinner than the other and is inserted in parallel with the coil LI Ltd. 24.

www.americanradiohistory.com DECEMBER 19th, 1928. Mp® hog 815 W.ogild

How to Secure the Maximum Output under Receiving Londitions. By R. W. W. SANDERSON, M.Sc. HE development of the modern valve has resulted have troubles peculiar to themselves. At their best they T in a very greatly increased emission with a are bulky, heavy for the same capacity as a dry cell, diminished filament current. Practically every and are capable of doing much more damage to the wireless set has its " power valve," this generally taking surrounding furniture. They must be carefully looked about 8o per cent. of the total anode current of the set, after or they deteriorate. They have the merit of giving where sets of the simpler type are being considered. The a more constant voltage in comparison with a dry cell, result is that there is often very little difference between the fall during effective life being about 15 per cent., in the total anode, currents of, say, 2, 3, and 4 -valve sets comparison with 3o per cent. for a dry cell. Where where only one power valve is used. exceptionally high anode currents are required they are, It is also true that practically all modern sets consume however, almost essential. more watts in their H.T. than in their L.T. circuits. As the price of batteries in pence per watt hour is very much Characteristics of the Leclanché Dry Cell. greater in the former case, the importance of a knowledge A battery of dry cells gives its rated voltage, that is, of the best way in which to use them is obvious. the -voltage on the label, only for the first few hours of Measurement of Anode Currents. its life. As circumstances vary, it is IN view of the fact that impossible to give a general Only there must be figure, a very small proportion of many millions of people dependent but considering the normal standard wireless for their set owners have any accurate entertainment upon the use small unit at, say, five milliamperes, idea of their anode currents. Some, of dry cell H.T. batteries it is of in- terest to review the voltage of a single cell falls from indeed, make an effort to measure it, the position of that much -maligned but almost indispen- the 1.5o volts, upon which the total but it must be emphasised that any sable component. battery voltage is calculated, to 1.4o measurements either of current It is not the purpose of this or article volts in the course of six periods of voltage that can be relied upon must to defend the dry cell high-tension bat- tery for it needs discharge of four hours each. Fre- be made with a moving -coil instru- no defence, but to discuss the intelligent use of it in those quently batteries of reputable make ment of good quality. Cheap volt- circumstances where it is the most are found on the market with in- meters have their convenient source of supply. use provided that dividual cell readings below 1.5o they are regarded as nothing The great majority of wireless more listeners still volts, although no current has been than a rough indication. They use dry cells and will serve probably continue to do so. It is for taken out of the cell. This initial well for detecting completely " dud " the information of this large group figure is dependent, to a great sections of a battery. of people that this article is written. extent, upon the type In the of material used absence of an instrument a in the manufacture of the fairly accurate estimate cell, and it of the anode current can gener- does not necessarily follow that the cell with the ally be made by calculation low from the published charac- reading will give a short life, though admittedly if teristic curve supplied the by the valve manufacturers. A discrepancy is very pronounced the tendency would be knowledge of the anode current is essential when the in that direction. For this reason it has been the custom , H.T. battery is being chosen. of most manufacturers, among them the best known The different sources in of high- tension supply are well the country, to " give away " an extra cell or cells in known, they are the " eliminator " and batteries. their batteries ; that is, they calculate the Whether voltage at 1.5o an eliminator is suitable in any particular case volts on a number of cells less than that actually present, depends upon the type of electric power available, the the additional cells giving them a safe margin. anode current required, At one and the type of set. Some sets time it was quite usual to find batteries labelled " 15 require considerable modification before they will work volts " giving well over 16.5 volts. satisfactorily It is an obvious with an eliminator. psychological fact that a buyer who gets Accumulators, a battery reading satisfactory in many cases where care more than the rated voltage is very satisfied, even if is exercised and where in- charging facilities are available, dividual cells are below the proper readings, as they

11 27

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s'o Wpig@OO DECEMBER zgth, 192,T. WOpIIC Dry Cell H.T. Batteries.- charge at constant current are shown in Fig. i. They easily may be, when certain types of material are used. are results selected from many which have been ob- The initial drop in voltage from 1.5 to 1.4 volts is tained, and they are typical of the discharge curves of fortunately not continued. Batteries made by the best two very well -known makes. methods when tested intermittently at a rate of five As will be seen, both batteries fail at about the same milliamperes will have an average voltage throughout point, and therefore they have given the same number their life of 1.3 volts or over. (This refers to the standard of ampere hours. In spite of this there is no doubt small unit.) about which is the better battery. The one with the A feature of the advertisements made by certain battery higher voltage, and therefore with the higher watt hours, is obviously the better. The " recovery " of the poorer cell is shown to be greater than that of the better one. It is customary for some makers to carry out tests on a constant resistance rather than a constant current. This means that at the end of the life of the cell the load is very much reduced, the current often falling to half its original value. In effect this permits the cell to give a very long " tail " in the discharge curve, which is never found when the cell is tested on an intermittent constant current test. H.T. Battery with Replaceable Sections. The most satisfactory way to use a high- tension battery, both from the point of view of economy and good results, is to find that voltage of high- tension supply which will give most satisfactory results either in quality cr ability TIME OF INTERMITTENT DISCHARGE (HOURS) to pick up distant stations, and maintain the voltage at that point by the provision of new batteries. For this Fig. l.- Intermittent discharge curves of two typical small -size purpose, small units (such as r5-volt strips) are ideal, cells delivering a constant current of 5 mA. for 30 hours per week. Both batteries have the same ampere -hour capacity but the watt - as they can be discarded separately as they become hour capacity of battery A is greater than battery B. useless, not before all available power has been used. If a user does this, he will obviously get better service manufacturers is the " recovery " of the battery be- from the type of battery where the volts are well main- tween discharge periods. Actually all batteries recover, tained. the degree of recovery depending largely upon the extent It has often been stated that it is unwise to put old to which the battery fell during the previous day's run. batteries in series with new ones. Provided that the This recovery may be looked upon in a light which does old ones are not practically useless, that the user has a not make it so favourable for the battery maker who method (such as a voltmeter test) for detecting " dead " makes this claim. It obviously implies that the battery sections, and that his set is provided with means of pre- falls considerably during the course of the day's run, venting back coupling through the battery resistance, for the degree of recovery must be measured by the this statement need not be taken seriously. difference between the final reading of one period, and If the voltage on the set be maintained constant it is the initial reading of the next. It is actually found that clear that the anode current will also remain constant, the recovery of the very worst battery is very much 180 higher than that of the best, owing to its fall during the 160 working period (See Fig. r). 140 As in any norm:.l set it is of the greatest importance 120 that the voltage should re- 100 main constant during the JF course of the working > 80 period, the ideal battery would fall very little, if at 60 all, in which case its re- 40 covery would be negligible. Intermittent Discharge. 20 0 In practice, of course, all 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 cells used for wireless work are discharged intermittently. HOURS Two curves showing the Fig. 2.- Voltage discharge curve of a triple -capacity battery on a three -valve set comprising results of intermittent dis- two D.E.L. 210 valves and a D.E.P. 215. A 28

www.americanradiohistory.com DECEMBER 19th, 1928. MT®il@oo MpN, 817 Dry Cell H.T. Batteries. - normally will fail to work satisfactorily at about three - and for the purpose of determining the behaviour of fifths of the voltage recommended for use either by the batteries, the tests of the type given in the figures will set makers or the valve manufacturers concerned. be immediately applicable. As a rule, particularly with On the other hand, if, as the better type of battery, is more usual, the grid bias there is fortunately very is kept constant, and no little life left in the cell effort is made to maintain by the time it has reached the anode voltage, it is still this point, corresponding important to choose a bat- to about o.9 volts per cell. tery in which the volts are A discharge curve of a well maintained. The more complete battery under rapid diminution of anode working conditions is voltage of the battery B shown in Fig. 2. This is (Fig. i) as compared with selected from a series and A will cause the volume is typical. The set in to fall off, while distortion question was a simple set or inability to pick up with a detector and two weak signals will become L.F. stages, comprising apparent at an early stage. two D.E.L.2zo valves and The point at which the a D.E.P.215. In the con- battery will fail to work A H.T. dry cell manufactured by the General Electric Company. cluding instalment of this Each section of 15 volts is replaceable and can be discarded cannot be the same for separately as it becomes useless. article the anode require- each set as the needs of ments of typical sets will listeners vary, the quality often remaining passably be given, together with suggestions for H.T. batteries of good when the set can no longer pick up distant suitable capacity. stations. In the writer's experience, wireless sets (To be concluded.)

NEWS FROM THE CLUBS.

Secretaries of Local Clubs are invited to send in for publication club news of general interest.

Loud Speakers on Trial. of '' all hands to the pump " to get the new Hints on Working a Pentode. Comparative tests with loud speakers con- headquarters ready for 7929. When completed, At the meeting of cealed behind it is the M -igan and District a screen always provide a con- hoped that the new laboratory will be Technical College Radio Society on November siderable measure of excitement owing to the among the best equipped in the north. The 28th, startling Mr. J. Clarke, of Messrs. Edison Swan results often disclosed when the technical research will be under the leadership Electrical Co., gave an account of the processes identity of the instrument is revealed. The of Mr. A. R. Bentley (a vice -President of the involved in the manufacture of valves and sub- Swindon and District Radio Society carried out Manchester College of Technology). A new sequently demonstrated an event of an Ediswan Threesome this kind at its last meeting, and short -wave transmitter will also be installed. set. His practical tips on the manipulation of the voting on an ear test of music reception All woodwork, including benches, will be con- screened grid gave and pentode valves were much the honours to a home -made roll -type structed by members under the supervision of :appreciated. The Society held its first Christ- instrument employing wallpaper. On speech a Mr. J. Meadoweroft, while all electrical and mas Social borne on December 12th. -made diaphragm loud speaker was given power equipment will be in the charge of Messrs. Hon. Secretary, Mr, M. M. Das, B.Sc., Library the best vote. Later in the evening Mr. Tarrant Colbert and Levy. Street, Wigan. gave a display of moving coil loud speakers. The Society still has vacancies for a few O 0 0 Mr. A. Wainwright has been elected Chair- technically minded members. All interested are man. invited to apply for further particulars to the The Screened Grid Valve. lion. Secretary, Mr. M. Hill, Windyridge, lion. Secretary. Mr. J. Levy, 19, Lansdowne Okus, Swindon. Road, West Didsbury, Manchester. The screened grid valve was the subject of 0000 an interesting talk given by a representative of the Marconi Co. at a recent meeting of the An A.C. Mains Set. Wembley Wireless Society. The talk. which was A set drawing all current illustrated by lantern slides, provoked an in- from A.C. mains teresting discussion, revealing was demonstrated by Mr. Remington. ex -vice- FORTHCOMING EVENTS. the keen interest chairman of the South Croydon and District which is being taken in the subject. ]radio Society at the last meeting. Using a WEDNESDAY, DECEMBER 19th. The feature of the evening was the denionstra= simple bell transformer, pure A.C. was obtained &alders Green and Hendon Radin Society. tion of one of the latest Marconi sets operating at the required voltage. Owing to the presence At 8 p.m. At The Club House. II'ilÌi- a moving coil loud speaker, of " hum " the detector filament was not run /delrt Way, N.IV.11. Demons( ration of On December 7th the evening was devoted off the Mains, Fehlt Finding, by Mr. C. L. Thom peon. to a comparative test of loud speakers, mem- an indirectly heated cathode North valve being used in this stage. The set in- ñlidrll.esex Bailin .Suricty. -At bers bringing their own instruments along. cluded one H.F valve, 8 p.m. At St. Paul's Instil etc, Il'in clr Particulars regarding the fortiieuuuug session followed by a detector more hill. Questions an,! .4 os i,, rs. and two stages of L.F. amplification. Among will be gladly forwarded by the Hon. Secretary, Edinburgh and District Radio Snricty.- Mr. H. ('omben, 24, Fark Wembley. other interesting features was an arrangement At 8 p.m. At 117, George Street. i rr- Lane, whereby an exceptional amount of play could ture by 3Ir. W. Anderson, 0 0 0 0 be obtained with the diaphragm of the moving F.R.S.E. coil. Tottenham A-iretrss Society. -At 8 p.m. Moving Coil v. Exponential Horn. At 10, Bruce Grove, N.19. Cinema and Hon. Secretary, tir. E. L. Cumbers, 14, - Camp Lanterne Lecture. A comparison of the moving coil and ex- den Road, South Iiuydon. ponential loud speakers was THURSDAY, DECEMBER 20th. hon the feature 0 0 0 of the Bee Radio Society's meetings on Iffori/ and District Radio Society.-:1t November 15th. The moving coif demonstrated the IVesleyan Institute, Cleveland /toad, by Mr. Reford gave excellent reproduction, Manchester and Club Research Scheme. Higer. Road, Ilford. Discussion : The Pros and Cons of the New Valses." while the demonstration of the horn instrununt As a step in their vigorous research campaign, by Mr. Clarke revealed Radio Stretford and District Radio Society.-- the excellent resulte the Experimental Society of Manchester A any al Dinner. obtainable from this class of loud speaker as have obtained premises at 8, Water Street, Slade !Indio (Birmingham)_ .ft 8 p.m. compared with the ordinary horn type. Opinion which will shortly be opened as club room and At the Parochial Held, Broomfield Road, was divided on the respective merits of the laboratory. The whole of the work is done by Erdhrgton. Sale and Exchange of moving coil and the logarithmic horn. members, and for the time being all meetings, Apparatus. lion. Secretary, Mr. A. L. Odell, 171. Tras- lecturers, etc., are cancelled, as it is a case niere Road, S.W.18. A 29

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818 l pßll@@9 DECEMBER Nth, 1928. Would

Events of the Week in Brief Review.

ATLANTIC WIRELESS OUTPOST. ESPERANTO BROADCASTING. WIRELESS SOCIETY OF IRELAND. A wireless station is to be established At the British Esperanto Association's Professor F. E. Hackett, Ph.D., M.A., at Horta, in the Azores, to supply meteor- annual dinner on December 8th it was has been elected President of the Wire- ological information to ships. announced that regular transmissions are less Society of Ireland. 0000 now made in Esperanto from 56 broad- 0000 casting stations. NEW SWEDISH BROADCASTER. 0000 R.C.A. CONCENTRATES ON In a few days' time the Swedish Broad- BROADCASTING. GERMANY 'PHONES THE The Radio Corporation of America has casting station at Malmö is to be replaced ARGENTINE. by a new station at Hörhy, in Skane, authorised the formation of a subsidiary with a power of 20 kilowatts. The wireless telephone service between company to take over its communications 0000 Berlin and Buenos Ayres opened on De- business. It is believed that the new cember 10th, the cost for a three -minutes both the Western BROADCASTING OIL ON TROUBLED organisation will control WATERS. conversation being £9. The system em- Union and the Communications Depart- ploys the Transatlantic telephony services ment of Radio. King Amanullah is reported to be using from Rugby. 0000 broadcasting to influence public opinion 0000 during the present revolt of the Afghan A NOTABLE JUBILEE. tribesmen. Pacificatory speeches have A " B.B.C." FOR CANADA ? The Jubilee of the incandescent electric been broadcast from Kabul and also re- Members of a Royal Commission lamp, which was first shown in public by produced on loud speakers erected in the appointed in Ottawa are to tour Britain, the late Sir Joseph Swan at Newcastle - main square of the capital. France, and the United States to gather on -Tyne on December 18th, 1878, will be 0000 data concerning the respective merits of commemorated by the Institution of Elec- and owned broadcasting. AID BY WIRELESS. State privately trical Engineers at the ordinary meeting MEDICAL is believed that Canadian authorities service It to be held on Thursday, December 20th, In starting an aerial medical for favour a broadcasting system designed on on Swan's work pioneers in the Western backwoods, the 1928, when a short lecture B.B.C. lines. will be delivered by Mr. J. Swinburne, Australian Inland Mission is making ex- The members of the Commission are Sir will be periments with portable wireless trans- F.R.S. Samples of early lamps John Aird, President of the Canadian on exhibition. mitters and receivers of a type suitable Bank of Commerce, Mr. C. A. Bowman, D000 for summoning assistance from the nearest editor of the Ottawa Citizen, and M. DE- NATIONALISATION ? medical settlements. Frigon, of the Montreal 0000 Augustin director The Belgian Government is reported to Polytechnic School. be considering a new project for re- SUNDAY CONCERTS FROM HOLLAND. .+000 organising the post and telegraph ser- The Hilversum broadcasting station is WIRELESS- CONTROLLED WATCHES? vices which control broadcasting. In continuing_ its fortnightly concerts for The Soviet Inventions Bureau, says the view of the financial advantages gained British listeners on Sunday evenings by Daily Telegraph, has granted patent from the exploiting of the hitherto arrangements with Messrs. Brandes, rights to a Roslave wireless engineer nationalised railways by a private com- Limited. The next transmission will be named Zlotnikov in respect of his inven- pany, it is proposed to deal in the same on December ZOth on the usual wavelength tion of a so- called ` master wireless way with other State services. of 1,071 metres. clock " which, it is claimed, will keep Should the scheme materialise, the 0000 any number of specially adapted clocks, Government would grant to the new THE " RADIOVISOR." and even watches, synchronised. P.T.T. concessionaires an annual subsidy 0000 A public company known as Radiovisor of some one hundred and fifty million Foreign and Colonial, Ltd., was regis- NEW WIRELESS CENTRE. francs for a period of five years, at the tered on December 5th with a nominal The Aldwych and Kingsway district of expiry of which the company would be capital of £450,000. Among the objects London, which is rapidly becoming the expected to carry on without further of the company are the manufacture and hub of the British engineering world, has assistance From that period the con- sale of selenium and other light -sensitive made an important acquisition in the shape cessionaires would be called upon to give cells, microphone fire alarms, moving -coil of the new wireless and electrical show- a reliable postal, telegraphic, and tele- apparatus, wireless and television appara- rooms opened by the B.T. -H. Company at phonic service to Belgium and to return tus and loud speakers. Crown House, Aldwych, on December 6th. to the State an annual sum equivalent It is understood that the company will A section of the showroom is devoted to to 5 per cent. interest on the subsidies also produce the " Radiovisor," a light - a fine display of B.T. -H. radio apparatus. advanced. The scheme provides for a sensitive device to work alarm bells, con- including Mazda valves and the latest sinking fund as well as a necessary trol trains and carry out other operations gramophone -radio sets. A photograph of reserve capital limited to fifty million which can be effected by the action of a the showroom appears on p. 833 of this francs. All excess profits would be re- light -sensitive cell. issue. payable to the Belgian Exchequer. A 30

_ www.americanradiohistory.com DECEMBER 29th, 1928. 'Mp4@go 819 WOptcll LONELY WIRELESS JOB. events for satisfactory reception by wire- Bouvet Island, a barren rock in the OWING to the Christmas less listeners. I have not refused per- South Atlantic, the ownership of which Holidays mission for the use of the British Broad- has been the subject of contention be- '' The Wireless World " dated casting Corporation's stations for tele- tween Britain and Norway for many December 26th will be on sale on vision tests. The Governors of the Cor- years, has now been unconditionally re- poration decided, in the exercise of the cognised as Norwegian property. A Monday, December 24th. discretion vested in them, after a de- meteorological wireless station is to be monstration by the Baird Company, who erected at once, and already two wireless hold an experimental licence, that the operators have left Oslo to begin their MERCANTILE MARINE WAR system did not at present fulfil the con- lonely task of installing and operating the MEMORIAL. ditions which would justify a public trial new plant. Iis connection with the unveiling of the through one of their stations. I have 0000 Mercantile Marine War Memorial on recently received an application from the ANOTHER WIRELESS " LIGHTHOUSE." December 12th, the wireless operators Baird Company for further facilities. The wireless beacon installation at Start who served during the War, number- This application is at present under con- Point, just completed by the Marconi ing some 6,000, were represented by sideration, and I am not yet in a position Company, is the seventh of its kind round twenty operators from the Marconi to say anything further. the British coasts. The others are at International Marine Communication 0000 Round Island, Skerries, Spurn Light- Co., Ltd. One of these, Mr. Robert Licences for Portable Sets. ship, the Casquets (Channel Islands), Leith, Nvho was senior operator on Replying to Sir Frank Nelson, Lord the a.setanio when on Bar Lightship, and Albatross (Coning - she was sunk Wollner, Asst. Postmaster -General, said beg, Ireland). May 17th, 1915, was presented to Her that he did not think there was any This type of station transmits an inter- Majesty the Queen. reason to suppose that the owners of mittent signal on an exclusive wavelength On the fateful day of the sinking of portable sets were more prone to evade of 1,000 metres for the benefit of ships the vessel, Mr. Leith at the time of the their legal obligations than other mem- carrying direction- finders. The comple- impact of the torpedo was lunching in bers of the community. The number of tion of the Start Point transmitter the saloon, the junior operator being on licences now in force was over 2,500,000. means that ships can now obtain effective watch. Mr. Leith tells us that when he 0000 bearings from the three Channel stations came down a lady on his left remarked Daily Profit on Rugby Station. and can be assured of their position right that he was late and would not get any Sir Nicholas Grattan -Doyle enquired up the Channel. lunch. These words of jest came what had been the average daily all-in 0000 strangely true, for they had hardly been cost of the Rugby station from May 1st spoken when a dull EMERGENCY WIRELESS crashing thud was to date, and what had been the average FOR ULSTER. heard, and it became evident that some- : Northern Ireland is daily revenue during the same period. asking for an thing serious had happened. The S 0 S emergency wireless service for use on Lord Wolmer said that from May 1st call was sent out continually, until it was to September 30th last (which was the occasions when telephone and telegraphic evident that nothing further could be communication is cut off latest period for which complete statis- during storms. done ; then and then only the wireless 14ltajor J. T. Duffin, president of the Bel- tics were available), the average daily operators gave a thought to their own all -in cost of the station, including the fast Chamber of Trade, recently stated safety. Mr. Leith was able to jump that it seemed " rather outrageous that in receiving stations worked in conjunction some distance into a partially submerged with it, was £383, and the average daily 1928, on account of storms, Ulster should lifeboat which had been launched, and be cut off from the outside world." revenue was £397. coon later transferred to another. 0000 CANADIAN GOVERNMENT ASSISTS WIRELESS AMATEURS. BOOK REVIEW. SHORT WAVE EXPERIMENTAL STATION. Canada, in its endeavour to give the Wireless Trader Year Book and Diary, amateur transmitter every opportunity to E01.11V, ',sr! r..711 11114 METRES 1929. experiment, has already done extensive XMAS GREETINGS Manufacturers and users of all kinds work to enable him to carry on without FROM of wireless sets and components will wel- interruption when the Washington Radio come the fifth issue of the " Trader Year Convention comes into force on January Book," which fully maintains the repu- 1st. According to the convention it is tation established by its predecessors of ap-sncAnd a Very Happy New Year and Cud D.Y. necessary to bave the consent of other being the most complete list of wireless nations before Canadian amateurs can e ea mate Awe sung rec. strews ea. Nel. v et re eg. manufacturers, and one arranged in a con- work with foreign enthusiasts with the 11. Ir venient form for quick reference. The freedom they have enjoyed in the past. wireless and gramophone trades are now The first step, says a Monitor corre- so closely allied that the directory has spondent, was taken in August by Com- An amateur transmitter's Christmas card. been extended to include gramophone mander C. P. Edwards, who wrote to the manufacturers, and an entirely new sec- two telegraph companies in the Dominion, THE AC3 RECEIVER. tion has been added after the technical the Canadian National Telegraph and the The Ferranti milliammeter used in the data giving much useful information and Canadian Pacific Railway's Telegraphs, " A.C.3 " receiver dealt with in our practical points for gramophone traders. and obtained their consent to allow issue of September 5th was erroneously The general features of this useful and amateurs the- freedom of sending experi- described as having a scale reading of technical data have been retained and mental and personal messages as would 0.15 milliamperes The figure should brought up to date. Those interested in not otherwise find their way over the have been 0.50 milliamperes, type 3F. the. question of royalties on patents will wires. The same indefatigable official 0000 find a useful summary of the various then sent letters to all British Dominions, WIRELESS patents owned by the Standard Tele- the United Kingdom, the United States, AT WESTMINSTER. phones and Cables, Ltd., and a brief Portugal, the Philippines, and a number Front. Our Parliamentary Correspondent statement of the position regarding the of other South American and European P.M.G. and Television. Marconi royalties at the time of going countries. In reply to questions in the Souse of to press. ' We are the first country to have Commons recently by Lieut.- Commander The book contains 388 pages of useful done this for the amateur," said Com- Kenworthy on the subject of television, information and includes a convenient mander Edwards in an interview. " We Sir William Mitchell- Thomson, Post- diary for 1929. Published by the Trader want the amateur to go right ahead with master- General, said : " I know of no Publishing Co., Ltd., Salisbury Square, his work when the new convention comes system which is at present capable of London, E.C.4. Price 5s. 6d. post free into force." transmitting moving pictures of actual for Great Britain, or 7s. 6d. overseas. A 31

www.americanradiohistory.com 820 WAp@Il®OR3 DECEMBER 19th, 1928. WOpild

'li=- =' P- AI if smul4 .,.w,:,..: .,:Tr. PROGRAMME1` FROM ABROAD

by Dr. Fischer. (Radio Barcelona), Call EAJI (344.8 gramme. 5.30, Legal Talk 6.0. BARCELONA "The Gc'dm Saturday ": (a) A StrJll through the ; 1.5 kW. -6.10, Sextet Selection, The Crown metres) be ? (c) An Service from La Town, (b) What is the Weather gcing to of the Indies (Elgar- Winter). 6.15, Variety Programme. Sextet Selections. 8.80, Hour in the Café. 8.0, 9.45. Basilica de la Merced. 6.25, Weather Report, News, Sports Notes and Dance Lesson by Prof. Martin. 9.0, Chimes, Weather French Music. 10.50, North Sea and Baltic Weather Report. Report, Exchange Quotations and News. 9.10, Selections of Dance Music. 10.0; Pro- Orchestral ; 5 kW. a.m., EAJ7. HILVERSUM (1,071 metres) -9.40 gramme relayed from Madrid, Time Signal and Daily Service. 11.40 a.m., Police Announcements. 11.55 a.m.; Concert of Trio Music. 1.5 Talk for BERGEN (370.4 metres) ; kW. -5.30, Orchestral Concert from the Tuschinski Picture Programme for Children. 7.0, Orchestral 1.40, Girls. 6.0, House, Amsterdam. 3.40, Italian Lesson. 4.40, Concert. Recitations by Sverre Erichsen. 7.50, SATURDAY, DECEMBER 22nd. 7.20, French Lesson. 5.40, Time Signal and Concert : Topical Talk. 8.0, Entertainment by Victor Iverson. Ojos negros (Camponi) ; Selection (Alongi) ; En 9.0, News and Time Signal. 9.15, Dance Weather sourdine (Tellam) ; Roses of the South (Johann Music. 11.0 (approx.), Close Down. MI Times are reduced to Greenwich Strauss) ; Pitchounette (Massenet) The Angel ; Spanish Serenade (Boris Lensky) ; ; 40 (Rubenstein) BERLIN (Königswusterhausen) (1.250 metres) Mean Time and are p.m. except Night in June (Friend). 6.25, German Le=sson. relayed from Hamburg. kW. -3.30, Programme 7.25, Police Announcements. 7.45, Concert and Talk : of 4.80, Else Kolshom, Talk The Employment where otherwise stated. arranged by the Workers' Radio Society. 11.15 Women in the National Post Office. 5.0, Prof. Woldt, (approx.), Close Down. Talk : Discussion between Industrial Workers. 5.30, Lesson. Prof. Werner Jäger, Elementary Spanish 5.55, WIZEN (340.9 metres) 4 k \V.-Transmits on 1,852 Talk : Ulrichs von Wilamowitz, on the Occasion of his 6.0, Programme relayed from Prague, followed by metres front 5.40 p.m. 12.10, Concert of Trio Music. Talk : The 80th Birthday. 8.20, Prof. Ehrenbaum, News. 9.25, Concert by a Gipsy Band, relayed from 2.40, Programme for Children. 5.10, Gramophone Herring Industry. 7.0, Concert : Bandonion Solos, Bratislava (300 metres). Selections. 6.10, Talk by M. v. Schyndel. 6.30. (a) March, Under the Hamburg Flag (Pörschmann), Catholic Bulletin. 8.40, English Lesson. 7.10. (b) Schiffsjungentanz (Zogbaunt) ; Tenor Solos, (a) BRUSSELS (508.5 metres) ; 1.5 kW.7.30, " Radio - Lesson in Dressmaking. 7.40, Talk by M. I.. J. N. Air from I,es Cloches de Corneville (Planquette), Chronique." 8.15, Concert from the Salle du Con- Feber. 8.0, Concert of Orchestral Selections and (b) Wer Hamburg nicht kennt (Raymond), (c) Deutsch- servatoire, followed by Esperanto Talk and News. Baritone Solos by M. W. Herckenrath. land, ade (Raymond) ; Readings by Dr. Gustav Manz ; 10.30, Orchestral Concert from the Palace Hotel Tea Tenor Solos, (a) Folk Song, Old Love (Kistenmacher), Room. 11.15 (approx.), Close Down. JUAN- LES -PINS (Radio LL) (244 metres) ; 1.5 (b) The Sailor's Destiny (Petrie), (c) Sailor's kW. -1.0, Orchestral Concert. 8.30, News, Talk for Chorus (Engel- Berger) ; Valse brillante in E Major BUDAPEST (556.6 metres) ; 20 kW. -4.10, Literary Women by Mme. la Comtesse de Tremeuge, and Concert. ( Pörschmann). 8.0, Programme from Voxhaus. Programme. 5.0, Gramophone Selections. 8.0, 9.30, Dance Music. 10.0, Close Down. 9.80, Dr. Werner Mahrholz, Talk : German Literature, German Transmission. 6.35, Reading. 7.0, Selection followed by Programme from Voxhaus. from Eltörött a hegedüm, Operetta (Zerkovitz- KALUNDBORG (1,153 metres) ; 7 kW.-Programme Szilágyi. 8.50, Concert by the Zigeuner Orchestra also for Copenhagen (337 metres).-6.30 a.m., Morning BERLIN (Voxhaus) (484 metres) ; 4 kW. -9.10 a.m. from the Hotel Hungaria. Gymnastics. 11.0 a.m., Chimes from the Town Hall. Market Prices. 9.15 a.m., Weather Report, News and 11.2 a.m., Orchestral Concert from W'ivel's Restaurant. Time Signal. 10.0 a.m., Programme of Gramophone CRACOW (588 metres) ; 1.5 kW. -4.10, Talk by 2.0, Programme for Children : ' What Ole Luköje Records. 10.30 a.m., Exchange Quotations. 11.55 Jotor on Flemish, French and Italian Tales. 4.35, showed Elsa and Jörgen "-Christmas Play with a.m., Time Signal. 12.30, Weather Report and News. Programme from Warsaw. 5.0, Programme from Songs (Johanne v. Kohl). 2.30, Vocal and Instru- 1.0, Programme of Gramophone Records. 2.0, Ex- Warsaw. 6.0, Miscellaneous Items and News. 6.25, mental Concert. 5.20, Peter Christiansen, Talk : change Quotations, Agricultural Report and Time Sig- English Reading by Mr. J. Stanislaysky. 6.55, Time Modern Foreign Authors- Gustav Hellström. 5.50. nal. 2.30, Dr. Paul Frank, Talk : Medical Hygiene. 3.0, Signal from the Astronomical Observatory. 7.0, Weather Report. 6.0, News and Announcements. Prof. Eduard Norden, Talk : Ulrich von Wilamowitz- Agricultural Report. 7.6, Dr. J. Regula, Talk : Last 6.5, (approx.), Exchange Quotations. 6.15, Time Moellendorff, on the occasion of his 80th Birthday. Week's Foreign Policy. 7.80, Programme from Signal. 6.30, Director V. E. Gamborg, Talk: The 3.80, Talk and Reading. 4.0, Concert : Selections of Warsaw. 9.0, Programme from Warsaw. 9.30, Enemies and Friends of Mankind. 7.0, Chimes from Opera Music from the Works of Puccini, (a) Manon Concert front a Restaurant. the Town Hall. 7.2 (approx.), Concert of Strauss Lescaut, (b) La Bohème, (e) La Tosca, (d) Madame Dance Music : Selections (Johann Strauss), (a) Butterfly, (e) Gianni Schicchi, (f) Turandot ; Moresca DUBLIN, Call 2RN (819.1 metres) ; 1.5 kW. -1.30, Radetzky March, (b) Annen Polka, (c) Waltz, Wo die (Silesu) ; Berg Musik (Borth) ; Suite (Fauchey) ; Weather Report and Gramophone Selections. 7.20, Citronen bliih'n, (d) Mazurka, Die Wahrsagerin, (e) Intermezzo appassionato Beere Nocturne Becte News, Announcements and Miscellaneous Items. Quadrille on Melodies from The Gipsy Baron ; Setec- Allegro giocoso (Fresco) (o ; Fox-Trot, Angela ram 7.30, Talk by Dorothy Day. 7.45, Irish Lesson by ticns (Joseph Strauss), (a) Dorfschwalben aus Oster - (Rapée) ; Ballet Suite, The Spring (Delibes) ; Jubel Seamus O'Duirinne. 8.0, Pib Uleann, by Seamus reich, (b) Mazurka, Frauenherz Diplomat Polka Serenade (Murzilli) ; La bella valenciana (Kaempfert) ; MacAonghusa. 8.15, Lecture Recital by Seamus (Johann Strauss) ; Selections (Eduard- Strauss), (a) Selection from The Snow Man (Korngold) ; Wiegenlied MacCall on Spanish Popular Songs, with Vocal Illus- Waltz, The Doctrine, (b) Gallop, Mit Dampf, followed (Reger) ; Sicilian und Rigaudon (Francur- Kreisler) ; trations by Eily Murnaghan (Soprano). 8.45, Variety by News and Announcements. 8.15, " Hans Peter's Tango, Süss singt die Geige, gut' Nacht (Rollins) ; Programme by Lettice Newman and Eric Richmond. Letter " -a Yule-tide Comedy in One Act by Otto Jubel Overture (Weber). Followed by Advertising 9.5, Selection by the Station Orchestra. 9.20, Variety Conradsen. "8.45, Concert of Light Music. 9.45. Notes. 6.0, Georg Hausdorf, Talk : Modern Adver- by Lettice Newman and Eric Richmond. 9.45, Dance Music from the Industri Restaurant. 1LD, tising and its practical application. 6.25, Psychology Selection from Katja the Dancer, Light Opera Chimes from the Town Hall. 11.02 (approx.), Close Talk by Dr. Max Dessoir. 7.0, Evening Entertainment. (Gilbert) with Gertrude Mortimer, Joseph O'Neill and Down. 8.0,. Programme of Christmas Carols by Cornelis the Station Orchestra. 10.30, News, Announcements Bronssgeest (Baritone) and Bruno Seidler -Winkler and Miscellaneous Items. 10.40 ( approx.), Meteoro- KATTOWITZ (422 metres) ; 10 kW.-3.0, Gramo- (Pianist). 8.30, Readings for Children by Fred Hilden - logical Report. 10.45 (approx.), Close Down. phone Selections. 4.10, Music Lesson by Prof. F. brandt, followed by Weather Report, News, Time Sachse. 4.35, Children's Letter Box. 5.0, Programme Signal and Sports Notes. 9.30, Lesson in Dancing by FRANKFURT (428.8 metres) ; 4 kW. -2.5, Programme for Children. 8.0, Announcements. 6.30, Talk by Reinhold Sommer, followed by Dance Music. 11.30 for Children. 3.85, Orchestral Concert of New Dance Prof. J. Dabrowski. 6.58, Time Signal and Agri- (approx.), Close Down. Music. 5.10, Reading by O. W. Studtmann. 5.30, cultural Report. 7.5, Talk by Mr. K. Zienkiewicz. The Letter Box. 5.45, Esperanto Lesson by W. 7.30, Programme from Warsaw. 9.0, Weather Report BERN (411 metres) ; 1.5 kW.-4.0, Concert by the Wischhoff. 6.15, Talk by Walter Ulrich. 8.45, and News. 9.30, Dance Music. Kursaal Orchestra. 6.29, Time Signal and Weather Lili v. Baumgarten, Talk : The 75th Birthday of Report. 6.30, Hans Gurren, Talk : Advent and Isolde Kurz. 7.15, Programme relayed from Stuttgart, KAUNAS (2,000 metres) ; 7 kW. -4.30, Announce- Christmas Customs. 7.0, The Christmas Oratorio followed by Dance Music from the Café Sacher. ments. 5.0, Weather Report and News. 5.15, (Bach), relayed from Basle (1,010 metres). .8.50, Agricultural Report. 5.45, Popular Concert. 6.15, News and Announcements. 8.55, Weather Report. HAMBURG, Call HA (in Morse) (394.7 metres) ; 4 Health Talk. 6.30, Ness's. 9.5, Concert by the Kursaal Orchestra. 9.35, Dance kW. -9.15 a.m., News. 10.0 a.m., Programme of Music. Gramophone Records. U.10 a.m.. Weather Report. LAHTI (1,522.8 metres) ; 35 kW. -4.0, Orchestral 11.15 a.m., Exchange Quotations. 11.30 a.m., Concert Selections : March (Metallo) ; Russian Scenes (Ban - BRESLAU (322.6 metres); 4 kW. -3.30, Orchestral relayed from Hanover (297 metres). In the Interval tock) ; Waltz (Buceeri). 4.85, Talk. 4.57, Time Concert from the Goldene Krone Café. 5.0, Film at 11.55 a.m., Time Signal. 12.10, News. 1.40. Signal, Weather Report and News. 5.15 Orchestral Review. 5.25, Talk in Esperanto by Alfred Hanschke. Exchange Quotations. 2.30, Review of Books. 3.0, Selections : Slavonic Dance No. 16 (Dvorak) ; News 5.85; Landrat Neumann, Talk : The Silesian Border Illustrated Music Talk by Dr. Wilh. Heinitz. 3.30, American Wood Idylls (MacDowell). 7.45, in Town -Guhrau. 6.10, Shorthand Lesson. 6.40, Concert of Musical Fairy Tales, from the Works of Finnish and Swedish and Close Down. Discussion on Art between Curpart Popl and F. W. Wilh. and Jak. Grimms : Reading from Little Red Bischoff. 7.15, Evening Entertainment : A Christmas Riding Hood ; Orchestral Selection from Little Red LANGENBERG (488.8 metres) ; 20 kW.- Programme Number. 9.0, News. 9.30, Dance Music by the Station Riding Hood (Bendel) ; -Reading from The Fisherdtan also for Aix-la- Chapelle (400 metres), Cologne (283 Dance Orchestra. 11.0 (approx.), Close Down. and his Wife ; Orchestral Selection from The Fisher- metres), and Münster (250 metres).-12.5, Orchestral man and his Wife (Tscherepnin) : Reading. from The Concert. 1.30, Hints for the Housewife. 2.30, BRUNE (441.2 metres) ; .2.5. kW.- 5,15,.. Weekly Brave Little Tailor; Orchestral Selection from. The Finance Report. 2.40, Arthur Wurbs, Talk The Report for Journalists Prof. Casmir Jerabek. Brave Little Tailor (Zimmer). 4.30, Request Pro- Basis of Wireless Technology -The Electrical Oscilla. A 32

www.americanradiohistory.com DECEMBER 19th, 1928. pall® ó2l W©wll 1

Programmes from Abroad. Opera (Massenet) m the Intervals : Review of Art - Saturday, December 22nd. and Literature and Talk for Women, by Mine. Pompa- tion Circuit. 3.0, Talk for Women by Marie Theres dour. 9.50, News. 10.0 (approx.), CloseDown. van den Wyenbergh. 3.25, Talk. 3.45, " On a Sleigh through the Fairy Woods " -A Christmas SCHENECTADY, Call 2XAD and 2XAF (21,96 and Play with Light Music and Songs for Young and Old. All Times are reduced to Greenwich 31.4 metres) ; 30 kW.- 11.58, Weather Report: 4:45, Concert by the Langenberg Station Choir and 12.0 Midnight, Phil Spitalny's Musical - Programme; Orchestra : Introductory Talk by Friedrich Wilhelm Mean Time and are p.m. except relayed from New York. 12.30 a.m. (Sunday) Orches- Herzog ; Variations and Theme, Hans im Glück tral- Concert from the Hotel Onondaga, Syracuse. (Philipp) ; lllarienlieder (Hans Philipp) ; Geschichte where otherwise stated. 1.30 a.m., Musical Programme, relayed front New vom Franz Xaver Dampfkessel und der Dame Musica York. 2.0 a.m., Selections by the Male Octet, relayed (Weismann). 5.30, Prof. Dr. Boerschmann, Talk: from New York. 2.30 a.m., Selections`YSy 'Mildred The Chinese Landscape in Culture and Art. 5.50, Hunt and the Marimba Orchestra. 3.0 a.m., " Lucky Finance Report, Weather Report and Sports Notes. Recitations by Mr. Fridtjof Krohn. 8.30, Weather Strike," Programme relayed from New York. 4.0, 6.15, Schriftführer Carl Wörner, Talk for Workers - Report, News and Topical Talk. 9.0, National a.m., Time Signal. 4.2 a.m., Dance Music by the The Insurance of Office Workers. 6.40, Dr. von der Melodies played on the Hardanger Fiddle by M. Orchestra of the Hotel De Witt Clinton, Albany. Eyvind Groven. 9.30, Dance Music from the Hotel Leyen, Talk : Fairy Tales in the Literature of the World. 7.0, Variety Programme. 9.30 (approx.), Bristol. 11.0 (approx.), Close Down. STAMBOUL (1,200 metres) ; 5 kW. -3.30, Concert. News, Sports Notes, and Commercial Announcemeutk, 4.30, Market Report. 5.15, Concert of Turkish Music. followed by Concert of Orchestra] Music and Programme PARIS (Eiffel Tower), Call FL (2 650 metres) ; fi kW.- 7.30, Weather Report and Time Signal. 7.40, Vocal of Dance Music, under the direction of Herr Eysoldt. 5.0, Pasdeloup Concert. 7.10, Weather Report. and Orchestral Concert : Symphony No. 5 (Beet- 12.0 Midnight (approx.), Close Down. 7.30, " Le Journal Parlé." hoven) ; Songs ; Wedding March from Lohengrin (Wagner). 9.0, News and Close Down. PARIS (Petit Parisien) (340.9 metres) ; 0.5 kW.- LEIPZIG (365.8 metres) ; 4 kW. -8.30, Orchestral STUTTGART (379.7 metres) ; 4 kW. -2.0, Vocal and Concert. 4.45, Wireless News and Talk. 5.20, 8.45, Gramophone Selections. 8.50 (approx.), Talk. 8.55 (approx.), News and Announcements. 9.0, Orchestral Concert. 3.35, Programme relayed from Weather Forecast, Time Signal and Labour Market Frankfurt. 5.0, Time Signal and Weather Report. Report. 5.30, Programme from Königswusterhauseu. Selections by Artistes from the Opera and Opfra- Comique : Overture to La Fille de Figaro (Leroux) ; 5.15, Talk by Dr. Rappenecker, relayed from Frei- 6.0, Josef Greff, Talk : Psycho-Analysis. Dr. 6.30, Fantasia on Miss Decima (Audran). 9.25, News and burg (577 metres). 5.45, Legal Talk by Dr. Kallee. Fritz Reuter, Talk : A Musical Career. " A 7.0, Announcements. 9.30, Symphony Programme, under 6.15, Willi Marcard, Talk: With Skis across the snow Winter Idyll ": Orchestral Selection, The Greenland fields of the Black Forest, relayed from the Direction of M. Estyle of the Conservatoire : Suite Freiburg. Suite (Frederiksen) Recitation, Winter (Prevert) ; funambulesque (Büsser) ; Bourrée fantasque (Chabrier). 8.45, Time Signal and Sports Notes. 7.0, Programme Recitations from The Seasons (Haydn) ; Songs, (a) News and Miscellaneous of Recitations with Musical Interludes : Pianoforte Winter Evening (Schubert), (b) Christmas Snow 10.0, Items. 10.2, Orchestral Concert : Selection from The Fair Maid of Perth Solo front Turandot (Busoni) Recitations, (a) Der (Grieg) ; Orchestral Selections from Der Rodel- (Bizet) ; Song of the Mill (Sylvio Lazzari) ; Gaiety Spiegel (Arthur Silbergleit), (b) Blick in den Spiegel zigeuner (Snaga) ; Recitation from A Winter Idyll (Florent Schmitt). 11.0 (approx.), Close Down. in drei Jahrhunderten (Senta Neckel) ; Blues for (Stieler) ; Songs, (a) Greisengesang (Schubert), (b) Violin and Pianoforte (Ravel) ; Recitations (Polly Zum (c) ; Punsch (Schubert), Geborgensein (von Stein) Paris), Call CFR (1,750 Tick), (a) (Modeschau), (b) Neue Kollektion, (c) Mollig; Songs (Wolf); Recitation from A Winter Idyll PARIS (Radio metres) : 6 kW.- 12.30, Programme of Columbia Gramophone Colombine for Violin and Pianoforte (Drdla) ; Recita- (Stieler) ; Song from Die Königskinder (Romper. Records : La Péri (Dukas) ; Meditation from Thais tions, from (a) Geheimnis der Frauen (Eulenberg), dinck) Songs, (a) Winteranfang (Stöhr), (b) Winter- Massenet) by Albert Sammons (Violin) ; Organ Solo, (b) Ein Opfergang (Binding) ; Pianoforte Solo from landschaft (Stöhr), (c) Winterweihe (R. Strauss), Pastorale (Francis), by M. E. Collette ; Recitation, La fille aux cheveux de lin (Debussy). 8.0, " Die (d) Winterliebe (R. Strauss). 9.0, News, Sports Le Colibri (Chausson), Mme. Jeanne Montjovet; Inset Tulipatan "- Opéra -comique, in One Act (Offen- Notes and Announcements. Dance Music from by 9.30, Russian Song, Kolj Slavenj (Bortnjansky), by the bach). 8.45, Wireless Cabaret : Orchestral Sélection, Vozhaaa. Don Cossack Chorus ; Duet, Get Out and Get Under Susanne (Raymond) ; Das alte Lied (Löwe) ; Kennst the Moon (Shay, Tobias and Jerome), by Van and du das kleine Haus am Michigansee (Heymann) MADRID (Union Radio), Call EAJ7 (434.8 metres) ; Schenck ; Song, I Know That My Baby is Cheatin' Come (Dazar) ; Wenn zwei Blondines (Raymond) 3 kW. : -7.0, Chimes and Sextet Concert Agua On Me (Endor, Steinberget and Lambert), by Sophie Orchestral Selection, March of the Gladiators (Sousa) azucarillos y aguardiente (Chueca) ; Fantasia on Tucker, accompanied by Ted Shapiro and his Orches- " The Champion Boxer " -Farce in One Act (P Cavalleria Rusticana (Mascagni) ; Fantasia on La tra ; Fox -Trot, Felix the Cat, by Paul Whiteman 011op) ; Es kam ein Bursch (Raymond) ; Spiel' my granjera de Arles (Rosillo) ; Interlude by Luis Medina. and his Orchestra ; Fox -Trot, Kiss and Make Up Jazzband, Spiel ' (Granichstädten) ; Was der Onkel Dance Music 8.0, by the Palermo Orchestra, relayed (Bogate and Hoefle) by the Piccadilly Players; Dokter sagt (Herzog) ; Light Poetry and Prose by from-the Alkázar. 8.25, News. Market Prices. 9.45, Quasimodo (Sentis), by Lucchesi's South American Ferry Dittrich ; Träume, Liebling ; (Hirsch) ; Wenn 10.0, Chimes, followed by Two Musical Plays, (a) Orchestra in the Interval, News. 2.0, Market schöne Frauen nicht lieben (Sobotka)-; Wenn in " Los Descamisados " ( Cueca), (b) " Los Cadetes tie Prices and Religious Information. 3.45, Rosati Werder (May), followed by News. 11.iß (approx.), la Reina " (Luna), followed by News. 12.30 a.m. Concert, dedicated to Arras and Artois ; in the Concert of Gramophone Selections, relayed from Frei- (approx.), (Sunday), Close Down. Intervals, News. 6.30, Agricultural Report. 6.45, burg. 12.30 a.m. (Sunday), Close Down. Musical Selections. 7.30, Pianoforte Lesson by M. MILAN, Call 1MI (549 metres) ; 7 kW. Talk TOULOUSE (Radiophonie du Midi) (389.6 metres) ; 7.15, Pierre Lucas. 8.0, Dr. Ronbinovitch, Talk : The by M. G. Ardau. 7.25, News. 7.30, Time Signal. 8 kW.- 12.45, Concert. 8.0, Market Prices, Exchange Mentality of Naughty Children ; followed by Market 7.32, Concert : Quotations and News. 8.30, Orchestral Selections of Variety Quintet Selection, Serenade Prices and News. 8.15, Concert : " L'Après -Midi de (Mozart) ; Mezzo- Soprano (a) Abschied Marches. 9.0, Time Signal. Concert from the Solos, (Schu- Jocelyn " ; Chamber Music Dance Music by the 9.5, bert), (b) Du bist die (Schubert), (c) Noel Works of Ganne and Leoncavallo : Orchestral Selec- Rub' ancien Joss Ghislery Symphonians ; M the Intervals, News. ( Respighi) ; Programme from the Works of Guglielmi. tions, (a) Extase (Ganne), (b) Selection frbm'I Pag- News and Economic Report. liacci (Leoncavallo), (c) Selection from Hans the 9.55, 10.0, Relay of PITTSBURGH, Call KDKA (83 and 27 metres) ; Tzigane Orchestra from the Fiaschetteria Toscana. 25 kW. -11.0, News. 11.10, Studio Programme. Flute Player (Ganne), (el) Marche arabe (Ganne), 10.45 (approx.), Close Down. 11.80, Concert from the William Penn Hotel, Pittsburgh. (e) Overture to Les Saltimbanques (Gann) ; Seven 12.0 Midnight, Session Clock Chimes, followed by Selections from I Pagliacci (Leoncavallo) ; Two MOTALA (1.380 metres) ; 30 kW.- Programme also University of Pittsburgh Address and Reading from Marches with vocal accompaniment (Ganne), (a) for Stockholm (454.5 metres), Baden (1,190 metres), Charles Dickens' " A Christmas Carol." 12.15 a.m. La Marche Lorraine, (b) Le père La Victoire. 9.50, Göteborg (416.5 metres), Malmö, (260.9 metres), (Sunday), Home Radio Club, by James W. H. Weir. Programme of Tangos : Marion (Holländer) ; Moments Osteisund (720 metres), Sundsvall (545.6 metres). - 12.30 a.m. Gems of American Literature, by Elbert R. équivoques (Holländer) ; Al quines Noies (Pujol) ; 4.0, Light Music by Braeckman's Orchestra, relayed Moses. 12.45 a.m., A Week of the World's Business, Tendre colloque (Vinale) ; Plegaria (Bianco) ; Can - y from Falun (357 metres). 5.0, Programme for Children. by Dr. Julius Klein. 1.0 a.m., Violin Solos by Godfrey cionero (Buzon). 10.15, North African News. 10.30 5.30, Old -Time Dance Music by the " Spelmanspoj- Ludlow. 1.30 a.m., Vocal Selections. 1.45 a.m., (approx.), Close Down. karna," relayed from Göteborg. 6.15, Burgomaster Instrumental Selections. 2.0 a.m., The Philco Hour. VIENNA (517.2 metres) ; 15 kW.-3,0, Orchestral Marten Sjökvist of Grönköping, Talk : Christmas and 3.0 a.m., Longines Time. 3.30 a.m., Weather Report. Concert. 4.10, Reading by Alfred Neugebauer from Yuletide Customs, relayed from Göteborg. 8.30, 3.35 a.m., Selections by Tracy Brown's Orchestra the Works of Herder. 4.55, Siegfried Loewy, Talk : Talk : The Porkbutcher's Trade. 6.45, Pianoforte from the William Penn Hotel Pittsburgh. Mathilde W'ildauer. 5.25, Readings front the Works Recital by Algot : Haquinius Scherzo in F Sharp of Isolde Kurz and Erwin Kolbenheyer. 6.20, Concert Major (Mendelssohn) ; Etude in B Flat Minor POSEN (344.8 metres) ; 1.5 kW. -6.50, Talk for by the Auber Trio. 7.10, Time Signal, Weather (Mendelssohn) ; Spring (Mendelssohn) ; Song Novel- Women. 7.10, Miscellaneous Items. 7.30, Programme Report and News. 7.15, " Doktor Klaus Comedy ette in E Major (Schumann). 7.0, Cabaret Programme from Warsaw. 9.0, Töne Signal and News. 9.30, in Five Acts (L'Arronge), followed by Dance Music, relayed from Malmö. 8.0, Current Events. 8.45, Radio Cabaret. 1L0, Concert, arranged by the Maison front the Grill Room of the Hotel Bristol, and Photo - Dance Music by the Egerstam Orchestra, relayed from Philips. 1.0 a.m. (approx.) (Sunday), Close Down. telegraphy Transmission. the Restaurant Riche. 11.0 (approx.), Close Down. (435 ; 1.5 kW. Poem Recita- PRAGUE (348.9 metres) ; .5 kW. -5.0. German VILNA metres) -8.5, tions. Soprano Songs by Mme. Sophie Wyle- NAPLES, Call INA (333,3 metres) ; 1.5 kW. -7.50, Transmission. 8.0, " Halka " (Moniuszko), from the 8.15, News and Harbour Notes. 8.0, Time Signal. National Theatre, Prague. 9.0, Time Signal, News and zynska. 8.30, Programme re.a ed from Warsaw. 8.2, 7.0, Talk. 7.30, Programme .relayed from Warsaw. Variety Programme : Orchestral Selection, Overture Theatre Review. 9.25, Concert by a Gipsy Band, to Light Cavalry (Suppé); " The Thief," Comedy relayed from Bratislava 000 metres). 10.30 (approx.), Close Down. (Bernstein) ; : in the First Interval Orchestral Selec- WARSAW (1,1U metres) ; 10 kW.-5.0, Programme tions (Centola), (a) Minuet, (b) Canzonetta in the RIGA (528.3 metres) ; 4 kW. -4.0, Programme of for Children. 6.0, Miscellaneous Items. 8.30 Second Interval : Musical Selections (Blom), (a) Minuetto Talks. 5.30, French Lesson. 6.0, Concert : Orchestral " Radio-Chronique," by Dr. M. Stepovsky. 6.58, della bambola, (b) Serenata d'amore. 9.0, Talk. Selections, (a) Overture to Im Reiche des Indra Time Signal. 7.0, Agricultural Report. 7.5, News 9.50, News. 9.55, Calendar and Programme An- (Lincke), (b) Ballet from Giroflé- Girofla (Lecocq), and Announcements. 7.30, " Gipsy Love "- Operetta nouncements. 10.0, Dance Music from the Trocadero. (c) Latvian National Waltz ; Comedy ; Orchestral in Three Acts (Lehár). In the Interval, Theatre 10.30 (approx.), Close Down. Selection, American Potpourri, Hallo I (Lubbe) ; Review. 9.0, Aviation Notes and Weather Report. Comedy ; Orchestral Selections, (a) Serenade (Mendels- 9.5, News and Announcements. 9.20, Police Report OSLO (481.5 metres) 1.5 kW.- Programme relayed, sohn), (b) Au vent frais qui murmure (l'esse), (c) and Sports Notes. 9.30, Dance Music from the Oaza by Fredriksstad (434.8 metres), Remar (555.6 metres) National March followed by News. 8. 0, Weather Restaurant. 10.30 (approx.), Close Down. Notodden (411 metres), Porsgrand (500 metres) and Report. 8.30, Concert, relayed from the Café de Rj (448 metres). -5.0, Programme for Children. l'Opera. 10.0 (approx.), Close Down. ZURICH (588 metres) ; 1 kW. -8.17, Concert of 6.15; "Weather Report and News. 8.30, Talk by Helge Orchestral Music and Humorous Selections. 7.15, Fóssum. 7.0, Time Signal. 7.2, Concert of Orchestral ROME, Call IRO (447.8 metres) ; 3 kW. -7.10, Time Request Programme. 9.0, Weather Report and News. Selections and Songs by Miss Greta Syrdahl. 8.0, Signal and Announcements. 7.45, " Cinderella," 9.10. Gramophone Selections of Dance Music. A 33

www.americanradiohistory.com 822 DECEMBER 19th, 1928.

Programmes from Abroad Teddy Petersen ; in the Interval, at 11.0, Town Hall. - SUNDAY, DECEMBER 23rd. Chimes, relayed from Copenhagen. 11.30 (approx.), BARCELONA (Radio Barcelona), Call EAJ1 (844.8 Close Down. metres) ; 1.5 kW.-11.0 a.m., Relay of Cathedral Chimes. 11.5 a.m., Weather Report and Forecast KATTOWITZ (422 metres) ; 10 kW.-9.15 a.m., and Aviation Route Report. 1.30, Concert by the All Times are reduced to Greenwich Relay of Church Service. 10.58 a.m., Time Signal. Iberia Trio, with Gramophone Records at. Intervals. 11.0 a.m., Weather Report and Forecast. 11.15 a.m., 2.45 to 5.30 (approx.), No Transmission. 5.30, Opening Mean Time and are p.m. except Popular Concert by the Wireless Quartet. 1.0, Talk. Signal, followed by Relay of an Opera from the Gran L20 and 1.40, Two Talks on Agriculture. 2.0, Weather Teatro del Liceo, Market Prices and Exchange Quota- where otherwise stated. Report. 2.15 Relay of Symphony Concert, from the tions in the Intervals. 8.0 to 8.20, Talk under the Philharmonic Hall, Warsaw : B. Policjant, Concerto auspices of the Catalonian Institute of Agriculture at for Violin (Tchaikowsky). 5.0, Concert. 6.0, An- San Isidro. 8.20, Concert by the Wireless Orchestra: Chimes. 8.5 a.m., Evangelical Festival with Address nouncements. 6.25, Humorous Programme by Prof. Suite (G. Chevignard), (a) Prelude, (b) Minuet_ Signal. Talk, arranged by. in the interval. 10.0 a.m., Fritz Worm : The Honour St. Ligon. 6.56, Time 7.0, (c) Sarabande, (d) Air de danse, (e) Tambourin. of the German Language. 12.0 Noon, Concert of the Institute of Pedagogy. 7.80, Concert. 9.0, 8.40, Sports News. 9.0 (approx.), Close Down. Orchestral Music. 1.30, Talk. 3.30, Popular Concert. Weather Report and Forecast, News from the Press 7.0, " Der Gläserne Berg," German Fairy Tale by and Sports Notes. 9.30, Dance Music. 10.30 (approx.), BERGEN (370.4 metres) ; 1.5 kW.-9.30 a.m., Relay Josefa Elstner -Oertel. Music by Walter Braunfels, Close Down. of Sacred Service. 11.30 a.m., Weather Report and followed by Late News Bulletin, Sports Notes and Forecast and General News Bulletin. 4.0, Church Light Musical Selections. 11.0 (approx.), Close KAUNAS (2,000 metres) ; 7 kW. 2.30, Children's Service. 7.0, Concert by the Wireless Orchestra. Down. Corner. 3.0, Programme for Young People. 3.30, 7.50, Current Events. 8.0, Talk. 8.30, Song Recital Health Talk by Dr. Jurgelionis. 4.0, Talk by J. by Mrs. Ragnhild Halvorsen (Soprano) ; Kristenfolkets CORK, Call 6CK (400 metres) 1.5 kW. -8.0, Pro- Ardickas. 4.50, Weather Report and Press News. Laulehelg (Solheim)..9.0, Weather Report and Forecast, gramme relayed from Dublin. 11.0, National Anthem 4.55, Talk. 6.5, " Woman and the Home," by O. te News Bulletin and Time Signal. 9.15, Dance and Weather Report and Forecast. 11.15 (approx.), Masiotiene. 6.30, Sacred Recital : Die Ehr Gottes in Music. 11.0 (approx.), Close Down. Close Down. die Natur (Beethoven). 9.30 (approx.), Close Down. 40 kW. 4 BERLIN (Königswusterhausen) (1,250 metres) ; CRACOW (566 metres) ; 1.5 kW. 9.15 am. to 10.45 KÖNIGSBERG (308 metres) ; kW.- Programme -7.55 a.m., Relay of Chimes from the Garrison Church a.m., Relay of Cathedral Service. 10.56 a.m., Relay of relayed by Danzig (272.7 metres). -8.0 am., Morning at Potsdam. 8.0 a.m., Morning Recital and Address, Fanfare from the Church of Notre Dame, followed by Festival, with Choral Renderings and Address in the relayed from Voxhaus, followed by Chimes from Berlin Time Signal and Weather Report and Forecast. Interval. 10.5 a.m., Musical Programme. 8.0, Cathedral. 10.30 a.m., Concert, relayed from Voxhaus. 1L10 am., Relay of Programme from Warsaw. Orchestral Concert. 7.5, Christmas Oratorio (Johann 12.45, Experimental Phototelegraphy Transmission. LO and L20, Talk on Farming. 1.40, La Chronique Sebastian Bach), conducted by Hermann Scherchen; 1.30 to 2.25, Agricultural Talks from Voxhaus. 8.0, Agricole. 2.0, Weather Report. 2.15, Concert Tenor Solos by Josef Poemer. 9.15, Late News Talk. 3.30, Musical Selections. 5.0, Series of Talks, relayed from Warsaw. 4.20, Talk. 5.0, Programme Bulletin and Sports Results. 9.30, Dance Music. arranged by the " Deutsche Welle," followed by Relay from Warsaw. 6.55, Time Signal from the Obser- 11.30 (approx.), Close Down. of Concert or Opera. 9.15, Press News. 9.30, Dance vatory. 7.0, Relay of Fanfare from the Church of Music. 11.30 (approx.), Close Down. Notre Dame. 7.30, Concert of Chamber Music devoted KOSICE (1,140 metres) ; 5 kW. -8.0 am., Recital of to the works of Polish Composers ; Violin and Piano- Sacred Music. 11.0 a.m., Time Signal followed by BERLIN (Voxhaus) (484 metres) ; 4 kW. 7.55 a.m., forte Sonata by François Brezezinski. 9.0, General Chimes from the Cathedral and Orchestral Concert: Chimes, relayed from the Potsdam Garrison Church. News Bulletin relayed from Warsaw. 9.30, Concert Rhapsody in A Flat Major, Op. 45, No. 3. 5.80, Talk. 8.0 a.m., Recital of Vocal and Instrumental Music, relayed from a Restaurant. 10.30 (approx,), Close 6.0, Time Signal and General News Bulletin, followed followed by Chimes from Berlin Cathedral ; Address Down. by Chimes. 7.30, Announcements and Concert. 10.0 in the Interval. 10.30 (approx.), Concert. 1.0, (approx.), Close Down. Elementary Lesson in Morse by Hans W. Priwin. DUBLIN, Call 2RN (319.1 metres) , 1.5 kW. -8.0, 1.30 to 2.25, Programme of Talks on Agricultural Handel's " Messiah," by the Dublin Philharmonic LAHTI (1,522.8 metres) ; 35 kW.-Programme also Subjects. 2.30, Reading of Stories. 3.0, Talk. 3.30, Society, conducted by Mr. Turner Huggard ; Soloists : for Helsingfors (375 metres). 7.0 am., Relay of Church Musical Programme. 5.40, Talk. 6.0, Talk. 7.15 Joan Elwes, Joseph Farrington, Elsie Black and W. F. Service. 9.50 am., Press News. 10.5 a.m., Concert. (approx.), Concert, followed by Weather Report, Late Watt. 10.30, National Anthem and Weather Report. 10.50 a.m., Weather Report and Time Signal. 110 News Bulletin and Sports Notes. 9.30, Dance Music 11.15 (approx.), Close Down. am., Relay of Sacred Service in Swedish. 3.0, Concert by the Dajos Bela Orchestra. 11.80 (approx.), Close by the Wireless Orchestra. 3.50, Talk. 4.10, Selec- Down. HAMBURG, Call HA (in Morse) (394.7 metres) ; 4 kW. tions by the Station Orchestra : Hungarian Dance -Programme relayed by Bremen (272.7 metres), (Brahms). 4.30, Talk. 4.57, Time Signal and BEZIERS (158 metres) ; 0.6 kW. -8.30, General Hanover (297 metres) and Kiel (254.2 metres). - Weather Report and Forecast. 5.10, Concert by the News Bulletin. 8.45, Concert, arranged by the Maison 7.25 a.m., Time Signal. 7.30 am., Weather Report Station Orchestra. 5.30, History Talk. 6.0, Recital of Cabannel, followed by Market Prices. 10.30 (approx.), and Forecast, followed by General News Bulletin. Music. 7. 45, General News Bulletin given in Finnish Close Down. 7.50 am., Talk. 8.0 am., Legal Talk. 10.0 a.m., Talk. followed by News in Swedish. 8.30 (approx.), Close 11.55 a.m., Time Signal, relayed from Nauen. 12.5 (for Down. BRATISLAVA (300 metres) ; 1 kW. -8.0 a.m., Relay Hamburg and Kiel), Concert. 12.5 (for Bremen). of Sacred Recital of Music from Bränn. 9.31 a.m., Programme of Music. 12.5 (for Hanover), Light LANGENBERG (468.8 metres) ; 20 kW.-Programme Agricultural Report, relayed from Prague. 2.0, Music. LO, Children's Corner. 6.30, Talk, arranged also for Aix -la- Chapelle (400 metres), Cologne (283 Puppet Play. 3.30; Orchestral Concert. 4.30, Trans- by the Hamburg School of Physical Training. 6.40, metres) and Munster (250 metres). --6.45 am., Boxing mission for Workers. 5.0, Talk. 5.30, Sports Talk, Sports News. 6.55, Weather Report and Forecast_ Instruction by Dr. Ludwig Bach. 7.5 am., Summary relayed from Prague. 6.0, Concert, relayed from 7.0, Concert or Play. 9.30, Weather Report and Late of the Week's Programmes given in Esperanto by Prague : Selections of Music for Wind Instruments._ News Bulletin, followed by Programme of Light Music. .Alfred Dormamrs. 7.15 am., 011y Wirtz Koort's 6.45, Talk, relayed from Prague. 7.0, Concert from 10.50 (for Hamburg, Bremen and Kiel), Weather Lesson on the Lute and Guitar. 7.35 am. to 7.55 a.m. Prague, followed by General News Bulletin. 9.20,. Report for the North Sea. and Baltic. 11.0 (approx.), Esperanto Lesson by Alfred Dormanns. 8.0 am., Relay of Dance Music. 10.30 (approx.), Close Down. Close Down. Church Chimes. 8.5 am , Evangelical Morning Re- cital and Address. 10.0 am., Talk by Fritz Worm. BRESLAU (322.6 metres) 4 kW.- Programme HILVERSUM (1,071 metres) ; 5 kW.-12.10, Concert 1L0 am., Organ Recital by Professor Haus Sachem. relayed by Gidwitz (329.7 metres). 8.15 a.m., Chimes by the Wireless Trio. L40, Talk. 2.10, Concert of 12.0 Noon, Orchestral Concert. L30, Talk. 3.30, relayed from Christ Church. 10.0 am., Evangelical Orchestral Music. 7.40, Time Signal. - 7.42, News Orchestral Selections. 7.0, Concert or Play followed Recital of Sacred Music with Address. 11.0 a.m., Bulletin, Weather Report and Sports News. 7.55, by Late News Bulletin, Sports News and Dance Music Concert. 1.0, Talk on Horticulture. 1.10. Talk or Concert by the Augmented Wireless Orchestra, con- conducted by Herr Eysoldt. 110 (approx.), Close Literary Programme. 1.35, Chess Talk. 2.0, Stories ducted by Nico Treep ; 'Cello Solos by Michael Busch. Down. for Children. 2.30, Agricultural Talk. 4.15, Concert. 10.40 (approx.), Close Down. 7.15, Concert : " Silesrars Christmas " (Hans Kaergel). LEIPZIG (365.8 metres) ; 4 kW.- Programme relayed 9.0, Late News and Announcements. 9.30, Dance HUTZEN (340.9 metres) ; 4 kW.-Transmits from by Dresden (275.2 metres). 7.30 am., Organ Recital. Music. 11.15 (approx.), Close Down. 5.40 on 1,852 metres. -8.5 a.m., Relay of Morning 8.0, am., Concert with Vocal and Instrumental Solos. Service. 9.30 a.m., Sacred Service. 12.10, Concert by 10.0 am.. Talk. 10.30 am., Talk. 11.0 am., Instru- BRÜNN (441.2 metres) ; 3 kW. -8.0 am., Recital of the K.R.O. Trio. 1.10, Talk. 1.40, Talk. 2.10, mental Music. 12.0 Noon. Agricultural Talk. 12.30, Sacred Music. 9.0 a.m., Agricultural Talk. 9.30 Orchestral Concert. 5.30, Relay of Evening Service Horticultural Talk. 1.0, Gleanings from the Foreign am., Notes on Agriculture relayed from Prague. (on 1,852 metres) from Amsterdam ; Sermon by the Press. L45, Wireless Talk. 3.0, Musical Programme. 10.0 a.m., Morning Concert. 3.30. Orchestral Concert Minister, the Rev. J. L. Schouten. 7.10, Talk. 7.50 5.30, Talk. 6.0, Talk. 6.30, Concert. 7.30, Concert 4.30, Programme relayed from Prague. Transmission (approx.), ytrchestral Concert. 10.25, Epilogue by of Chamber Music by the Dresden String Quartet and for Workers. 5.0, Programme of News and Music " Le Petit Cheeur," conducted by Mr. Jos. H. Pickkers. Soloists : Schubert's Quintet in G Major Op. 163 for for German Listeners. 5,30, Talk on Sport by Mr. 10.40 (approx.), Close Down. Two Violins, Viola and Two Cellos, (a) Allegro ma non Laufer relayed from Prague. 6.0, Concert of Orches- troppo, (b) Adagio, (c) Scherzo Andante Sostenuto tral Music. Slavonic Rhapsody in G Minor Op. 45 KALUNDBORG (1,153 metres) ; 7 kW.- Programme Presto, (d) Allegretto. 9.0, Sports News. 9.30, Dance (Dvorak). 7.0, Concert relayed from Prague. 9.20. also for Copenhagen (337 metres). -9.0 a.m., Church Music relayed from Berlin. 1130 (approx.), Close Down. Relay of Dance Music. 10.30 (approx.), Close Down: Service, relayed from Copenhagen. 10.80 a.m. to 10.40 a.m. (Kalundborg only), Weather Report and LYONS (Radio Lyon) (291 metres) ; 1.5 kW. 7.30, BRUSSELS (508.5 metres) ; 1.5 kW.-.5.0, Selections Forecast from the Copenhagen Meteorological Institute. Le Journal Parlé with General News Bulletin and News of Light Music. 6.0, Children's Corner. 6.30 (approx.) 12.0 Noon to 12.25, German Lesson, arranged by from the Press. 8.0, Concert with Solos by Madame Concert. 7.30, La Radio Chronique. 8.15, Radiolytteren." 12.30, French Lesson, arranged by Ducharne of the Lyons Conservatoire (piano) ; M. Orchestral Concert. 10.15, Late News Bulletin and " Radiolytteren." 2.0, Orchestral Concert. 5.50 Camand (violin) and M. Testaniére (cello) ; Selection Press Notes. n.0 (approx.) Close Down. (Kahmdborg only), Weather Report and Forecast from The - Barber of Seville (Rossini). 9.0 (approx.), from the Meteorological Institute. 6.0, News from the Close Down. COLOGNE (283 metres) ; 4 kW.-Programme also Press. 6.15, Time Signal, followed by Talk. 7.15, for Aix-la- Chapelle (400 metres), Langenberg (468.8 Vocal and Instrumental Concert Christmas in Music MADRID (Union Radio), Call EA J 7 (484.8 metres) ; metres) and Mpnster (250 metres).-6.45 a.m., Lesson and Poetry ; Concerto grosso, No. 8 in G Minor for 1.5 kW.-Programme relayed by Salamanca (EAJ22) in Boxing by Dr. Ludwig Bach. 7.5 am., Review in Two Violins, 'Cello, Strings and Cembalo, (a) Vivace, (405 metres). -11.30 a.m., Concert by the Municipal Esperanto of the Week's Programmes. 7.15 am., Grave, Allegro, (b) Adagio, Allegro, Adagio, (c) Vivace, Band relayed from EI Retiro (Weather itting); Lesson on the Lute and Guitar by 011y Wirtz Koort. (d) ,Allegro, Pastorale, Largo. 10.0, Dance Music, Conductor, Maestro Villa. LO to 2.0, NoTrmission. 7.35 am., Lesson in Esperanto. 8.0 am., Church relayed from the Palace Hotel, under the direction of 2.0, Chimes and Time Signal. 2.5, Concert by the A 34

www.americanradiohistory.com DECEMBER 19th, 1928. 823 nWOO ill Programmes from Abroad. - The Orchestra, March from " The Damnation Vif Sunday, December 23rd. Faust " (Berlioz). Talk in the interval. 9.50, Labe Station Orchestra with Soloists ; Interlude by Luis News Bulletin. Medina. 3.30 to 7.0, No Transmission. 7.0, Chimes. 10.0 (approx.), Close Down. 7.5, Selections by the Wireless Sextet and Item by SCHENECTADY, Call 2XAD and 2XAF (21.98 and Luis Medina. 8.0, Dance Music by the Palermo Orches- All Times are reduced to Greenwich ; kW. tra relayed from the Alkazar. No Trans- 3L4 metres) 30 -4.0, Relay of Church Service. 8.30 to 10.0, 8.80, Organ Recital by Elmer A. Tidmarsh, relayed mission. 10.0, Chimes and Time Signal. 10.5, Concert Mean Time and are p.m. except from by the Band of Wad -Ras by the Union College Memorial Chapel at Soheneo- the Regiment, conducted tady,N.Y. 9.0, Talk for Men by Dr. S. Parkes Cadman, ,Don Pablo Cambronero. 12.0 Midnight, Chimes where otherwise stated. relayed from followed by Dance Music by the Palermo Orchestra New York. 10.30, Arcadie Birkenholz from in Violin Selections, relayed from New York. 11.0, relayed the Alkazar. 12.30 a.m. (approx.) Programme by the Stetson Parade, relayed from (Monday), Close Down. Boston, Mass. 1L30, The Acousticon Programme 9.25, General News Bulletin. 9.80, Symphony Concert. from New York. 12.0 Midnight, The Old Company's MILAN, 1111 (549 metres) ; 7 kW. -9.0 a.m., Opening 10.0, Late News Bulletin. 10.15, Concert of Orches- Programme with Songs by Reinald Werrenrath Signal and English Lesson. 9.30 a.m. to 10.15 a.m., tral Music. 11.0 (approx.), Close Down. Sacred Recital (Baritone), relayed from New York. 12.30 a.m. with Soloits. 11.30 a.m., Time Signal (Monday), Relay from the Capitol Theatre, New York. 11.35 a.m., Concert by the Radio Quartet. 12.30 PARIS (Renie Supérieure), Call FPTT (458 metres) ; 2.0 a.m., David Lawrence : Talk on "Our Govern- to 8.0, No Transmission. 3.0, Opening Signal. 3.5, 0.5 kW.-Programme relayed at intervals by the ment," Concert. 4.30, relayed from Washington, D.C. 2.15 Me., Light Music relayed from the Fiaschet- follpwing stations : Bordeaux PTT (275 metres), Atwater Kent Hour, relayed from New Ycrk. 3.15 teria Toscana. 5.0 to 8.55, No Transmission. 8.55. Eiffel Tower (2,650 metres), Grenoble (416 metres), a.m., Correct Time. 3.17 a.m., Performance of the Opening Signal. 7.0, Current Topics. 7.15, History Lille (284 metres), Limoges (285 metres), Lyons PTT National Light Opera Company from New York. Talk by C. A. Blanche. 7.25, Sports Results. 7.30, (480 metres), Marseilles (303 metres), Rennes (280 4.15 a.m., Experimental Transmission of Television Time Signal. 7.35, " The Daughter of the Regiment," metres), Toulouse PTT (260 metres). -8.0 a.m.. General Signals. 4.30 a.m. (approx.), -Close Down. Opera by Donizetti. At the end of Act Two : Sports News Bulletin and Time Signal. 9.25 a.m., Inter- Notes and News from the Stefan[ Agency. national Time 10.30 Signal and Weather Report. 12.0 STAMBOU'L (1,200 metres) ; 5 kW. -3.30, Concert. (approx.), Close Down. Noon, Concert. 1.0, Le Journal de France Economique. 4.80, Market Prices. 5.15, Selections of Turkish 1.80, Concert organised by the General Association of Music. 7.30, Weather Report and Forecast, followed MOTALA (1,380 metres) ; 30 kW-Programme also French Wireless Listeners : Selection from " The Magic by Time Signal. 7.40, Talk on the History of Music. t,,r Stockholm (454.5 metres), Boden (1,190 metres), Flute " by Mozart. 2.30, Relay of Symphony Concert 8.0, Concert by the Stamboul Wireless Orchestra. Goteborg (416.5 metres), Malmö (260.9 metres), Oster. organised by the Paris paper " Le Journal." 4.0, 9.0, Late News Bulletin. 9.30 (approx.), Close Down. scud (720 metres), and Sundsvall (545.6 metres).- Pasdeloup Symphony Concert, relayed from the 10.0 a.m., Relay of Morning Service. Champs Elysées. 2.80, Literary Conductor: M. Rhené Bâton. TALLINN (408 metres) ; 2.2 kW.7.30 a.m., Relay Programme. 3.0, Concert. 4.55, Relay of Carillon 6.80, Le Radio Journal de France. 8.15, Sports Talk of Church Service. 12.30, Instrumental Concert. from the Town Relay of and Hall at Stockholm. 5.0, Results. $.30, Orchestral Concert. 10.30 (approx.) 4.45, Press News. 5.0, Concert : Selection from Evening Service. 8.15, Pelléas et Mélisande, Play Relay of Dance Music from the Coliseum de Paris. Cavalleria Rusticana (Mascagni). 5.30, Talk. 6.0, by Maeterlinck, with incidental music by Jean Sibelius. 12.0 Midnight (approx.), Close Down. Concert with Soloists. 9.0 (approx.), Close Down. 8.15, Late News Bulletin and Weather Report and Forecast. 10.0 (approx.), Close Down PITTSBURGH, Call KDKA (83 and 27 metres) ; 25 TOULOUSE (Radiophonie du Midi) (389.6 metres) ; kW. --4.0, Sessions Clock Chimes and Church Service. 8 kW.- 12.30, Weather Report and Forecast and MÜNICH (535.7 metres) ; 4 kW.-Programme relayed 8.30, Programme of the Whitehouse Coffee Company, Market Prices for Toulouse. 12.45, Vocal and Instru- by Augsburg (566 metres), Kaiserslautern (277.8 relayed from New York. 7.0, " Roxy's Stroll " from mental Concert. L0, Carillcn. L5, Concert (con- metres) and Nuremberg (241.9 metres). -10.0 a.m., WJZ, New York. 9.0, Organ Recital by Dr. Charles tinued). L45, News from " Le Télégramme," Chimes from the Munich Town Hall. 10.10 a.m., Heinroth, Director of Music at the Carnegie Institute. " L'Express " and " Le Midi Socialiste." 8.0, Prices Wireless Weather Chart for Bavaria. 11.06 a.m., 9.45, Service relayed from the Shadyside Presbyterian of Cereals and Exchange Quotations from Paris and Time Signal, Weather Report and Forecast and Pro- Church with Sermon by the Minister, the Rev. Hugh News from the Fournier Agency. 8.15, Mews from gramme Announcements. 2.0, Programme of Music. Thomson Kerr. 11.0, Relay of Concert from the the Press. 8.30, Concert. 9.0, Carillon. 9.10, 8.0, Concert. 5.30, Concert. 7.0, " Educated William Penn Hotel, Pittsburgh. 11.30, Concert by Concert arranged by " L'Association des Commerçants People," Popular Comedy in Three Acts by Victor the Whittall Anglo- Persians from New York. 12.0 Radio -électriciens du Midi " : Selections from Marion Leon, Adaoted for Wireless Transmission and Produced Midnight, Sessions Clock Chimes, followed by Service at by Massenet, (a) Je suis encore toute etourdie, by Rolf Pinegger, followed by late News Bulletin and the Cavalry Episcopal Church at Pittsburgh. Sermon Allons, Manon, plus de chimère. 10.15, The North Music. 11.0 (approx.), Close Down. by the Minister, the Rev. E. J. Van Etten. 1.0 a.m. African " Journal sans papier " and Late News (Monday), Musical Selections relayed from New York. Bulletin. 10.30 ( approx.), Close Down. NAPLES, Call 1NA (333.3 metres) ; 1.5 kW.-8.30 1.15 a.m., Collier's Radio Hour from New York. a.m., French Lesson by Professor Etienne Verdier. 2.15 a.m., Programme by the Utica Jubilee Singers VIENNA (517.2 metres) ; 15 kW.-Programme re- 9.0 a.m., Sacred Recital. 3.45, Children's Programme. relayed from WJZ, New York. 2.45 a.m., El Tango layed by Gras (357.1 metres), Innsbruck (294.1 metres), 4.0, Concert with Soloists 4.30, Time Signal. 7.30, Romantico relayed from New York. 8.15 a.m., Klagenfurt (272.7 metres), and Linz (254.2 metres): Current Topics. 7.50, Naples Harbour Report. Longine Time. 3.30 a.m., (approx.), Close Down. 9.20 a.m., Morning Recital of Music. 10.0 &m., 8.0, Time Signal. 8.2, Concert by the Station Concert by the Vienna Symphony Orchestra and Orchestra and Soloists : " Ah per sempre o mio POSEN (344.8 metres) ; 1.5 kW. -9.15 a.m. to 10.45 Soloists. 3.0 Orchestral Concert. 7.5, " Brüderlein bell' angiolo," from La Forza del destin (Verdi), a.m., Relay of Sacred Service. 11.0 a.m.. Time Signal. Fein," Old Viennese Musical Play in One Act by duet for Soprano and Tenor, by E. Blandi and G. 11.5 a.m. and 11.80 a.m., Two Agricultural Talks. Julius Wilhelm. Music by Leo Fall. Musical Director : Ferrero, with Pianoforte accompaniment. 9.0, 2.15, Relay of Symphony Concert from Warsaw. Josef Holzer. 8.30, Concert. 10.15 (approx.), Close Sports Results. 9.55, Calendar and Notes on the 4.20, Talk. 4.45, Talk. 7.0, Talk. 7.30, Vocal and Down. - next day's programmes. 10.0 (approx.), Close Down. Instrumental Concert : Soprano and Tenor Duet from WARSAW (1,111 metres) ; 10 kW. -9.15 a.m. to 10.45 Rigoletto (Verdi) ; sung by Maria Gasiorowska and Cathedral Morning Service. Time PARIS (Eiffel Tower), 5 Ladislas a.m., 10.58 a.m., Call FL (2,850 metres) ; Sowinski. 8.30, Recital of Music. 9.0, Time Signal. 1L0 a.m., Relay of Fanfare from Notre Dame k W. 7.58 a.m., Time Signal on 32.5 metres. 9.28 a.m., Signal. 9.5, General News Bulletin. 9.20, Dancing at Aviation Route Report and Time Signal on 2,650 metres. 5.0, Relay of Pasdeloup Lesson by Mr. Starski. 9.40, Dance Music relayed from Cracow. 1L5 a.m., Concert. 7.10 Report and Forecast. the Carlton Restaurant. Weather Forecast. 11.10 a.m., Warsaw Philharmonic to 7.20, Weather 11.0 (approx.), Close Down. Symphony Concert. LO to 2.0, Three Talks for 7.30, " Le Journal Parlé par T.S.F." Police Memoirs Farmers. 2.0, Weather Report and Forecast. 2.15, by Detective Ashelbé. 7.56, Time Signal on 32.5 PRAGUE (848.9 metres) ; 5 kW. metres: -8.0 a.m., Recital of Concert of Symphony Music by the Philharmonic 8.0 to 9.0, Vocal and Instrumental Concert, Sacred Music relayed from Brun. 9.0 a.m., Agricul- Orchestra. 4.20, Talk. 4.45, Talk on Aviation. 5.0, " Music and Moonlight," The Orchestra, " Invocation tural Talk. 9.30 a.m., Agricultural Report. 10.0 â la Nuit " (Charpentier). Orchestral Concert. 6.0, Twenty Minutes' Variety. 10.28, Time Signal on a.m., Concert. 12.5, Industrial Talk. 12.30, Talk Talk. 6.45, General News Bulletin. 6.58, Time 2,650 metres. 11.15 (approx.), Close Down. 6.20, on a Social Topic. 3.30, Concert of Orchestral Music. Signal. 7.0, C. Jablonowski, Talk : Divertissements 4.30, Transmission for Workers. 5.0, Programme for Intellectuels. 7.30, Popular Concert by the Polskie PARIS (Radio LL) (370 and 60 metres) ; 1 kW.- German Listeners, News Notes and Concert. 5.30, Radio Orchestra under the direction of J. Oziminski: 12.80, Programme arranged by Radio Liberté, General Sports Talk by Mr. Laufer. 6.0, Orchestral Concert of News Bulletin, " L'Arlésienne " Suite No. 1, by Bizet, (a) Prelude, followed by Instrumental and Vocal Popular Selections. 6.45. Talk. 7.0, Concert. 8.0 (b) Menuet, (c) Adagietto, (d) Carillon. 9.0, Aviation Concert. Artistes : Charles Seringes (Violin) ; Robert Concert. 9.0, Time Signal and Late News Bulletin. Report and Weather Report and forecast. 9.5, News Bergmann ; ('Cello) and Edouard Flament (Pianist). 9.15, Theatre News. 9.20, Dance Music by the from the Pclish Telegraph Agency. 9.20. Police and 1.0, Carillon de Fontenay. 3.0, Programme of Dance Orchestra at the Hotel Sramota. 10.80 (approx.), News. Music Music. Sports 9.80, Relay of Dance from the 9.0, Concert. 10.0, Carillon de Fontenay. Close Down. " Oaza " Restaurant. (approx.), Close Down. 10.15 (approx.), Close Down. 10.30 RIGA (526.3 metres) ; 4 kW.-8.0 a.m., Relay of ZAGREB (309.2 metres) ; 0.7 kW. -10.0 a.m., PARIS (Radio Paris), Call CFR (1,750 metres) ; 6 Sacred Service in German. 9.15 a.m , Sacred Service Concert of Instrumental Music. 4.0, Popular Dance kW. -8.0 a.m., General News Bulletin and Press Notes. (in Latvian), relayed from the Mara Church. 12.0 Music relayed from the Club- Cabaret. 8.45, Radio 8.30 a.m., Physical Training by Dr. Diffre. 12.0 Noon, Noon Stories and Musical Items for Children. 3.0, Talk. 7.0, Programme relayed from the National Religious Address. 12.30, News from the Press. 12.46, Concert by the Station Orchestra, conducted by Arved Theatre, Zagreb : ' Die Königin von der Barenburg," Concert by the Albert Locatelli Orchestra including Parups. 4.0 to 5.30, Four Talks. 8.0. Popular Opera in Five Acts. Music by Lujo Safranek-Kavic. Selection by Bilboquet. 4.30, Popular Gramophone ConcerL 8.0, Weather Report. 8.80, Concert re- In the Intervals : News and Announcements and Records by " L'Industrie Musicale." In the Interval : layed from the Café de l'opera. 10.0 (approx.), Weather Forecast. 10.0 (approx.), Close Down. Press News. 6.30, Agricultural Notes. 6.45, Gramo- Close Down. phone Records. 7.30, Press News. 7.45, The Radio (588 metres) ; 1 kW. Relay of Paris ZURICH -10.0 a.m., Guignol. 8.30, Concert of the Radio Paris ROME, Call IRO (447.8 metres) ; 3 kW. -8.30 a.m., Programme from the Capitol Theatre. 1L0 a.m., Music Hall. Artistes : Madame Fernande Izard and Opening Signal, followed by German Lesson. 9.0 Weather Report and Forecast. 11.30 a.m., Selections Madame Reine Chanteix ; The Orchestra conducted a.m., Recital of Vocal and Instrumental Music. 9.45 by the Station Orchestra. 3.0, Relay of Concert by the by M. Maurice André. In the Intervals : News from a.m., to 12.0 Noon, No Transmission. 12.0 Noon, Castellano Orchestra at the Carlton Elite Hotel the Evening Papers and Late News Bulletin. 10.80 Opening Signal. 12.5 to LO, Concert by the Wireless 6.80, Time Signal and Weather Report. 6.88, Concert (approx.), Close Down. Trio. LO to 4.0, No Transmission. 4.0 Opening of Chamber Music, Violin Solos by Erwin Gilbert and Signal. 4.5 to 5.30, Popular Concert. 7.10, Talk Cello Solos by Julius Bächi. 7.0, Programme of PARIS (Petit Parisien) (340.9 metres) ; 0.5 kW.- on Agriculture. 7.15, Sports Notes and News from Music. 9.0, Weather Report, Late News Bulletin and 8.45, Gramophone Records. 8.50, Talk. 8.65, News the Stefan[ Agency. 7.29, Time Signal. 7.31, Talk. News from the Neue Züricher Zeitung. 9.30 (approx.) from the Press. 9.0, Vocal and Instrumental Concert. 7.45, Concert by the Grand Symphony Orchestra: Close Down. A 35

www.americanradiohistory.com WIhresoo DECEMBER 19th, 192X. WoyIlcd éra1/eect, /e,`

Some Notes on the Pro= This article has been contributed by the perties and Method of Engineering Department of the Westing- house Brake and Saxby Signal Co., Using the Dry Metal who are the originators of dry -metal Rectifiers. type of rectifier in this country

ANY references to metal rectifiers have appeared consisting ut minute contact areas between dissimilar in the technical Press during the past few years, materials, have found that the detection is variable but it is thought that there is still room for some both in direction and magnitude, and research work has further notes on the subject, accompanied by definite shown that in such cases the effect is obtainable at the measurements to indicate the performance which may point of contact of many indifferent contact specimens. be expected under given conditions. In the metal rectifier the rectification takes place at the Dealing firstly with the theories recently advanced as surface of the metal on which the oxide has been covering the operation of the metal rectifier, we find that formed, not at a surface to which external connection is a thermoelectric effect is often put forward as offering made. a solution. That the rectification is not due to such Probable Electronic Action. an effect is proved by the fact that heating the rectifying This great distinction between the contact detectors, junction produces an E.M.F. in the wrong direction to so widely used in the early days of the wireless in- account for the rectification that actually takes place. dustry, and the true power rectifier cannot be too clearly Another theory advanced is that of the well -known understood. None of the explanations so far advanced electrolytic rectifier, but this theory is untenable in the for contact detectors accounts for the performance of the light of the instantaneous response without lag and lack metal rectifier, and this fact led Dr. Grondahl to publish of chemical change which are two of the outstanding the outlines' of an electron theory which agrees in prac- characteristics of the metal rectifier. tice with the measured characteristics of the rectifier. It has been suggested that the operation of the metal For the present it is easiest to think of the metal rectifier rectifier is similar to that of a large number of crystal as a diode, the cathode of which requires a minute or like detectors in parallel. Those who have investi- E.M.F. but no heating to cause electron emission, the gated the properties of ci \ stal or contact detectors, anode being formed by a layer of material formed on the surface of the cathode. All rectifiers are analogous to non-re- 3 f1 turn valves, and the fact that they pro- vide a uni- directional current from an 20 alternating source is due entirely to this fact. By suitably arranging two or more

2000 15 of these non -return valves both of the U) directional 2 impulses of an alternating = THIS CURVE IS THE POSIT VE current cycle can be passed in the same o_ 70 PORTION OF THE-MAIN - CURVE' direction to a uni- directional circuit. The DRAWN TO A LARGERt--I SCALE bridge connection preferred by the manu- i 1000 I facturers of the metal rectifier has the ad- vantage that the voltage applied to the rectifier need be little more than the out- 0 .1 2 3 put voltage required, whereas with the VOLTS + centre -tap connection a secondary of double this voltage is required, only one -4 -3 -2 2 3 half of the winding VOLTS being used for each half -cycle, an inefficient use of the trans - former copper. Fig. 1 -'l'y'pirul characteristic curves of the Westinghouse meta' rectifier showing the relation between resistance and voltage. t Science. September 24th, [926. 36

www.americanradiohistory.com DECEMBER 19th, 1928. WIpWM9 825 MIFild The Theory of the Metal Rectifier. - to be handled is negligible, and internal resistance is The fact that full -wave bridge -connected metal recti- secondary to rectifying ratio ; for this reason specially fiers are the commonest in radio work does not mean made rectifiers, having a high ratio even with appreci- that the rectifier is not used in the half -wave variety- able internal resistance, are preferable for this purpose. frequent applications of the " non -return valve " prin- The typical characteristic curves in Figs. i and 2 ciple to spark arresters, telephony, and telegraphy cir- show that there are decided optimum points in both the cuits are made with half -wave units. reverse voltage-resistance and consequently in the volt- It has sometimes been stated that the small reverse current shown in the characteristic curves of single rectifying discs would militate against the use of the rectifier for battery charging, but a little consideration will show that with a bridge -connected rectifier any reverse current can only result in an increase in A.C. input for a given D.C. output, but, assuming that the supply has failed, the battery E.M.F. would be applied in the re- verse direction to two arms of the bridge in series and two such paths in parallel. In practice the rectifier is so proportioned that even under such conditions the Fig. 3. -A metal rectifier feeding a capacity -inductance filter. The condenser K is charged to the peak value during discharge that can occur is negligible. each half- cycle. The characteristic curves of a typical rectifier are shown in Figs. r and 2. The characteristic curve is not age- rectifying ratio curves, and these optimum points a rigid one ; it has been found that certain treatments are used in designing rectifiers for special purposes. In óperation the rectifiers are only subjected to a low 10 forward voltage, this voltage being of the value neces- IIMMUMMEMEMUMMEN sary to drive the load current through the units in the MUME MMEMMINN, ME low- resistance direction, whereas the voltage at which each unit works and must withstand in the reverse direc- INIUMMIMMUNIMMIIM tion is much higher. For this reason static ratio curves MIUMMUMMINMOI MMI are not published here, since they would be misleading. MIUMMEEMNIUM MEIM Effective Cooling Necessary. MMIUMNI.MIENIMr,MMM Where the optimum point in the reverse voltage-re- sistance characteristic is not adopted as the design basis, MINIWOMMUMMArn the limitation on reverse voltage becomes the reverse OMMINI breakdown voltage. This reverse breakdown voltage is itself a variable depending partially on temperatures 5 E MME and mechanical pressures at the rectifying junction. The ENI/MI temperature limit is controlled by the use of cooling fins, 111======oil immersion, or other well -known methods of forced EMINIMEMEMEMMEMEM cooling, and the pressure feature by building the rectifier RIMMUMEMMER MIMMEM units with spring washers, giving a certain predetermined ME0 pressure which is maintained over the whole of the work- UMM ing temperature range. The latter feature accounts for NON IMEMMOMI one of the manufacturer's instructions that assembled IMEMME/EMIN rectifier units must not have the clamping nuts altered from the factory setting. NEMEIMMMOM In considering the maximum voltage to which recti- o _MMEMEMEMEM fiers may be subjected, the circuit being supplied is frequently the governing feature. In Fig. 3 a rectifier 5mA -MMWEEMOMMUM is shown feeding a capacity- inductance filter. In such .0 a circuit the condenser K is charged to peak value dur- VOLTS ing each half -cycle ; this peak voltage has to be with- stood by one arm of the bridge network of the rectifier. Fig. 2.- Current.-voltage characteristics of the metal rectifier. As each unit in the rectifier has a limitation on the re- verse voltage which it can safely withstand at the maxi- can be applied which will vary the characteristic widely. mum working temperature, it follows that this peak This feature enables special rectifiers for instrument work voltage will largely govern the number of rectifying and similar application requiring special performance to units to be used in each arm of the bridge. be constructed. It will be appreciated that a rectifier re- The forward resistance -voltage characteristic is largely quired to transpose an appreciable A.C. wattage to the a matter of area of the unit under consideration, and the equivalent D.C. wattage should primarily have a negli- question of large area and natural cooling or small gible internal resistance so that the losses of transposition area with assisted cooling is largely one for the manu- may not be appreciable. In instrument work the power facturer. A 37

www.americanradiohistory.com 826 pssIlmo DECEMBER 19th, ;928. MAO The Theory of the Metal Rectifier. - By paralleling a number of units in each arm of the bridge, the current - carrying capacity of the whole network can be increased to any desired figure. It may be of interest to mention the re- cent construction of series -parallel units running up to over i,00ò amperes at 12 volts for plating purposes, and of series units up to 8o,000 volts for potential purposes. Enough has been said above on the temperature limitation to indicate that ventilation of housings for metal rectifiers is important. The fact that the larger units have in themselves a considerable mass enables these units to take extra- ordinary high overloads for short periods of time, these overloads being insufficient to heat the mass of the unit to any serious degree. It is on record that one of the commonest units -that used in many Fig. 4.- Voltage regulation curves for the H.T.1 type of metal rectifier with well -known 0.5 amp. 6 -volt trickle 250 volts A.C. input. Both filter and resistance loads are shown. chargers -has repeatedly rectified io amperes for periods of 20 seconds without damage, a been prepared to show these differences when operating performance that few valves could emulate ! Such over- on resistance and filter circuits. loads, or, in fact, any load above the manufacturer's It will be noted from Fig. 4 that when operating on rated value, may not cause immediate damage, but will a filter circuit the output voltage is very high at low if sustained cause an increase in the forward resistance. loads ; it is obvious from this that transformers having One of the problems in determining what rectifier to high open- circuit voltages are undesirable.

Rectifier on a charging load of 3.0 amps. Charging a battery at 0.1 amp.

Rectifier charging at 1.0 amp. Rectifier with a non -inductive load. Fig. 5.- Oscillograms of output current. use to obtain a certain mean direct current from a filter A flash lamp bulb rated at 6 volts loo mA. placed lies in determining what additional current will be taken in the A.C. input leads of H.T. units is desirable. from the rectifier and dealt with as ripple current by the The output wave -form of the rectifier has been care- condenser immediately following the rectifier. To avoid fully studied, and the oscillograms reproduced in Fig. 5 increasing the load on the rectifier unduly, it is the show the wave -form of a typical unit operating manufacturer's practice to recommend 2 or 4 mfd. con- on open circuit, and when charging a battery at densers only across the output of the rectifier, these several loads. The wave -form is singularly free values being sufficient for the " H.T.i " type of unit. of any indication of lag in action or other com- As the measured performance of a rectifier will differ plication, facts which are of advantage in applying the with the nature of the load, the curves in Fig. 4 have rectifier to many uses. A 38

www.americanradiohistory.com DECEMBER r9th, 1928. Wfipph@o 827 %``IoTIl4

1----r:.,.

wIMIlATOR ,

Full Data for the Design 111 iRHll Ablesroosms Constructional of a Universal Details. H.T. Eliminator. ._---- By W. I. G. PAGE, B.Sc. ;iBildsa;,s. U11

(Concluded from page 991 of last week's issue.)

IN the first instalment of this article in last week's merciai size is 5,000 ohms, and this value is used. The issue it was shown to be almost impossible to de- condenser C, may have to withstand nearly the full sign an H.T. eliminator for A.C. mains capable of surge voltage, and should be of the type tested at fulfilling the needs of various types of multi -valve r,000 volts. receiver without a fairly heavy financial expenditure. To conform to regulations and to assure absence of Working Out Resistance Values. hum, motor boating, and distortion demand a multi- As regards the Megavox detector feed (HT +3), plicity of chokes, resistances and condensers which reference must be made to p. 725 of November have 28th been tested at high voltages. The theory concern- issue, where the equivalent circuit is shown in Fig. 2 (b) ing the isolation of each anode circuit, together with and the method of calculating the resistance values is the necessity of series feeds to all but those valves which given in the text. The potentiometer shunted across have exceedingly small currents, has been dealt with at 265 volts should pass considerably more current than some length, and it is now necessary to give construc- that taken by the valve when working under leaky grid tional details of the eliminator as specifically designed conditions ; a total value of 50,000 ohms has been con - for the Megavox- Three. idered satisfactory (passing between 5 and 6 mA.). The In calculating the values of the various resistances which perform the dual +H.T.q function of dropping volts o and smoothing out ripple, it CH., FUSE +H.T.g should be pointed out that LAMP o the D.C. resistance of the chokes, amounting to a few + ß.T.2 hundreds of ohms, CH .2 need not R +H.T., be taken into account. C,, Examining Fig. 6, and R7 taking first the pentode 10G -H T. (H.T. + 4) feed o at 150 volts RECTIFIER H.T. and 7.5 volts bias, FUSES the current is 21 mA. (see Fig. 2). The drop from SWITCH 265 volts (as shown in the e regulation curve, Fig. 4) to EARTHED METAL CONTAINING BOX 15o is rr5, which, when A.C. divided by 0.021 amperes MAINS (21 mA, expressed as am- peres), gives the value of Fig. 6. - The Megavox - Three eliminator circuit. CH 20 henrys; CH, 32 henrys R1, R, as 5,500 ohms approxi- b,1í00 ohms; R2, RI, 10,000 ohms; R4, 30,000 ohms Rp, R5, 20,000 ohms R7, 30,000 ohms; Cl, C1, 2 mfd. condensers, 1,000 -volt test ; C,, two 2 mfd. condensers In parallel, 1,000 -volt test; mately. The nearest corn- Cl, C;,, C,i, Cr, 2 mid. condensers, 500-volt test. A 41

I. www.americanradiohistory.com 828 WRp@IlSCO DECEMBER 19th, 1928. WOIrag.t Megavoìt Eliminator. - H.F. anode current 1.9 mA., and the R6, R, potentio- series limb of 20,00o ohms has been divided into two meter current 3 mA., giving a total of 5.4 mA., the value resistances of io,000 ohms each to assist in smoothing, of R; is obtained by dividing the difference between 265 whilst the second limb, R1, has a value of 30,000 ohms. and 150,-115 by 0.0054, which comes to about 20,000 Examining Fig. 2 (b) in the article already referred to, ohms. The condenser C. has to withstand the full surge and substituting the present values, it will be seen that voltage, and should be of the 1, 000-volt test variety ; when the "switch in the receiver is thrown over to leaky C, must also be of this-type, and consists cf two 2 -mfd. grid the applied voltage is 65, and under anode -bend condensers in parallel. The condensers C C3, C6, and C being connected on the receiver side of resistances of io,000 ohms and over, can safely be of the type tested at 500 volts. Gramophone Pick-up. If the Megavox -Three receiver has been modified for use with a gramophone pick -up, as described on page 622 of October 31st, 1928, issue, the resistances R4, R6, and R, can be re- moved from their clips, and R., and R3 replaced by re- sistances of 5,000 ohms each ; if these, however, do not provide sufficient smoothing a choke of 32 henrys could be interposed between the common posi- tive lead of th : rectifier and R.. The general layout of the components can easily be seen from the photo- graphs and from Figs. 7 and 8. The fuse lamp in the Burndept resistor holder is mounted on the top of a piece of half -inch wooden dowelling 3,1in. long, so as to be visible through one of the ventilation holes in the side of the safety box. The lamp will glow while the receiver is being operated, and will carry the momentary surge voltage Fie.7. -The baseboard layout A. The superstructure D Is held up by the two vertical boards B and C, to which the chokes are attached. without detriment. To facilitate lifting the conditions the voltage is about 14o, which, although a.' chassis clear of the safety box an ebonite rod 42ín. long little high, is not excessive. The triple potentiometer terminating with a cross piece is attached to the base- R;, R6, R,, feeding the plate and the screen of the board. ' The ebonite terminal strip with shrouded, screened grid valve has now to be considered. labelled terminals is raised from the top wooden plat- Assuming that R, will have to be of such a value that form by two pieces of ebonite tube. For rapid change the voltage at H.T. +2 is 150, it is evident that R6, R,, of resistances to suit new conditions, the resistance is shunted across 15o volts. A convenient total current holders have been labelled with numbers which corre- is 3 mA., which will pass with 50,00o ohms; if the spond to those in Fig. 6. 'These numbers can be cut limbs are made 20,000 and 30,000 ohms respectively out of an old calendar and attached by means of and the voltage at H.T. + 1 is worked out in accordance Chatterton's compound. Readers are not advised to with Fig. 2 (a) in the article entitled " Dropping Volts " depart substantially from the general layout, for there it will be found to be 83, which is a satisfactory screen is a reason for the position of every component ; the potential. transformer and rectifier, for example, must be close Knowing' the screen current to be about 0.5 mA., the together and as far away from the output end as pos- A 42

www.americanradiohistory.com DECEMBER 19th, 1928. Wilnkoo 829 WoplAll Megavox Eliminator. - that it incurs an additional expenditure when the re- sible. There should be no superstructure above the ceiver is being built. The four H.T. terminals would be rectifier which might prevent efficient ventilation. It is short- circuited for battery supply, and the lead XYZ advantageous to mount the metal -cased condensers removed for mains operation. The skeleton set shown touching each other in two banks of four, whilst the is a popular combination of screened -grid valve trans- chokes should be as far apart as possible from one former- coupled to an anode -bend detector directly another and away from the input end. It is possible coupled to an L.F. transformer, which, in turn, is con- for a choke, in spite of metal -shrouding, to have an nected to a single L.F. power valve. If with H.T. bat- external field. The logical place for the interchange- teries R15 and R,., are not required, dummy short - able resistances is on a platform near the lid of the circuiting bars obtainable commercially can be inserted box, so that access to them is easy. in the holders. The A.C. input through the 3- member flexible cable A D.C. eliminator for the Megavox-Three will be de- to the switch in the safety box is best derived from a scribed shortly, having a filter circuit similar to that wall plug, as it is generally easier to arrange an earth point at this position than at a lamp -holder. The five output leads from the eliminator are brought through two holes in the side of the box, and are terminated with insulated spade ends and ivorine tags labelled to correspond with the terminals on the Mega - vox receiver as modified in Fig. 2. The eliminator should be operated about i8in. away from the re- ceiver, for, although the former has an earthed metal case, there may be a small stray field. As this article will con- clude with a résumé of the considerations necessary when designing an H.T. eliminator with metal recti- fier for almost any multi - valve set, it is important to examine the question of the arrangement of H.T. ter- minals on receivers in general, for where the anodes of a number of valves have a common feed (without the use of de- view of the chassis showing the disposition of the chokes and the interchangeable resistances. coupling resistances) it may be found extremely difficult to avoid back -coupling and in the A.C. unit. The receiver will require slight modi- hum when an eliminator is used. It would seem desir- fication for the case where the mains have a positive able when designing a set which is destined to be used earth. with either H.T. batteries or mains equipment to pro- To return to the A.C. eliminator, the following sum- vide some of the resistances and by -pass condensers in mary may be found useful when designing such a unit the receiver, as by this means, on the one hand, there for any three- or four -valve set, the requirements of would only be one positive connection to the H.T. bat- which are not more than ioo mA. at 200 volts. It is tery, and distortion due to its internal resistance would assumed that the present layout will be followed in be prevented ; while, on the other hand, the eliminator detail as regards the relative position of chokes, resist- would need to have much less elaborate smoothing ances, condensers, fuse lamp, etc., and that the same equipment, and could be connected to the receiver, transformer-rectifier combination will be used. It should which would not have to be modified in layout or wiring. be pointed out here that the regulation curve for the Fig. 9 exemplifies such a suggestion, and, while its transformer alone shows a drop of only eight volts advantages will be appreciated, it must be admitted R.M.S. between no load and a load of roo mA. R.M.S , A 43

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Fig. 8. -The general wiring diagram. It may be more convenient to derive the A.C. input from a wall plug as explained in the text. which is a very creditable performance. That the regula- Even with metal shrouding there may be a small ex- tion curve given in Fig. 4 for the smoothed D.C. output ternal field necessitating the mounting of two chokes at ìw of the rectifier has a greater percentage drop than this a short distance from one another and, if possible, with is due to the inevitable effective resistance of the recti- their axes at right angles. The D.C. resistance of a fier, which, however, is small when compared with other choke need not be taken into account if it is low com- rectifiers. The transformer cannot be supplied for mains pared with that of the voltage- dropping resistances used with a frequency of 25 cycles. in the same lead. CONDENSERS to be used in an eliminator should Summary. have low internal resistance, otherwise a potential dif- CHOKES should be chosen with a specified induct- ference may be set up, resulting in back -coupling. To ance which is effective under the D.C. load conditions. withstand surge voltages ' all condensers connected A 44

www.americanradiohistory.com DECEMBER 19th, 1928. PIlCg 83r oPIlca1 Megavos Eliminator. - directly across the output of the rectifier, or only sepa- rated from it by a choke, should have been tested at 1,000 volts. If a condenser is connected to the rectifier by io,000 ohms or over, a voltage test of about 50o is adequate. RESISTANCES, while hav- ing the required current - carrying capacity, must also be capable of dissipating the watts without heating up. Resistances are used in an eliminator, not only to drop volts but also to assist Flg. 9.- Suggested arrangement for the H.T. feed to a multi -valve receiver. The are short -circuited for battery supply and the lead H.T. terminals in smoothing out receiver so designed gives XYZ is removed for mains operation. A ripple, so a better performance with H.T. batteries and when used with an that where, for instance, a eliminator the latter would require very simple smoothing equipment. resistance of 40,000 ohms is required to break down a is also convenient for the certain sake of economy to feed the voltage it may be advantageous to use two plate of a screened -grid valve from a potential 20,00o -ohm resistances divider in series and connect a by -pass which is common to the screen. It must be remembered condenser to the junction point (e.g., R2 and R3). that the greater the current passing through a potentio- SINGLE meter the less the change in voltage on the valve when SERIES RESISTANCES are used where the the current is comparatively current alters, but the less the smoothing by reason large, and where there is of the small no change in the steady D.C. current values of resistances used ; a compromise when signal ampli- must thus be struck. In tude is altered. Triode H.F. valves, leaky grid Fig. io EF represents a typical detectors, and feed to the plate and screen of a screened -grid valve, pro- all L.F. valves would be fed in.this vided that way. In Fig. 10 the lead AB H.F. transformer coupling is used. If tuned represents the usual feed anode is to an output valve where employed, a choke would have to be embodied a choke of low D.C. resist- in the lead ance is necessary. A EF, as in the eliminator for the Megavox. CD very suitable outp t valve when together with using this eliminator is the R. give adequate smoothing and a steady PX65o, which at 200 volts supply when signals H.T. will handle 8o volts grid of varying amplitude are applied swing. If another L.F. to an anode -bend detector. stage were used prior to the output valve two resist- ances in series would be needed, but no Two SCREENED -GRID VALVES coupled by H.F. choke. With transformers leaky grid detection the feed CD without R. would can be fed from one tapping, such as EF, be provided the satisfactory, and for a neutralised H.F. stage the lead that extra current taken is considered when EF without R6, R,, and C, would be used. fixing the values of R;, R6, and R,. Two VALVES IN PUSH -PULL can be operated from the POTENTIAL DIVIDERS are necessary for screen current lead AB. and for. the H.T. supply to an anode -bend detector It THE GENERAL PROCEDURE is to decide on the smoothing arrangement de- manded by the receiver cir- cuit, and to work out the +H.T. H.T. current CH a OUTPUT taken by the VALVE set plus the potentiometers (if R any). The voltage +H.T regulation curve ti O DETECTOR (Fig. 4) CH.o o will give the input voltage 5 to the filter for the total T. load, and the resistances F 0H -1 VALVE which are required to drop the necessary volts can be calculated. +H.T ()SCREEN FROM OXIDE C4 This RECTIFIER eliminator is avail- rmfds able for inspection by o readers at the Editorial Offices of this journal: Fig. 10. -A typical smoothing circuit 116 which can he adapted for use with almost any three- -117, Fleet Street, Lon- tour-valve set not employing tuned anode coupling. or don, E.C.¢. A 45

www.americanradiohistory.com 832 WATshog DECEMBER rgth, rg23. Worcllcl

1111dY91ll1llbipitllIlll'f1ul'vi.rb.

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By Our Special Correspondent. Broadcast Drama Developments. -" Research Programmes." -The Case of the Relays. - On New Year's Eve. 24 -Hour Time." -The Savoy Hill Site.- Interrupted Speeches.

Dramatic Changes. further emphasis it was surely furnished tralises- all northern . broadcasting at Various important changes are under by the deputation which waited upon Sir Manchester, to the detriment of local John Reith at Savoy Hill a few days talent. contemplation at Savoy Hill in connec- sympathy tion with the Dramatic Department. For ago. The B.B.C. expresses entire who The deputation, which spoke for the with local aspirations, but contends that instance, I hear that Val Gielgud, is essential in pre- in production citizens of Leeds, consisted of Sir the grouping system assists Eric Maschwitz the paration for the Regional Scheme which of the B.B.C.'s official organ, is to take William Hart (Town Clerk), the Deputy - will, it is hoped, provide a satisfactory over R. E. Jeffrey's duties, while Lord Mayor, the Pro Chancellor of Sheffield University, the Director of alternative service to every listener in " R.E." himself will devote himself to country. " Research Programmes." the 0000 0000 FUTURE FEATURES. Pertinacity Required. No Connection with Clapham. London and Daventry. It looks as if Sheffield and the other These " Research Programmes " have DECEMBER 23RD. -" The Messiah," re. affected towns will have to accept the nothing in common with activities of layed from York Minster, S.B from present situation with as good a grace as Captain West, who is busy in research Leeds. DECEMBER 25TH. -Service relayed from possible, but all fair- minded listeners will programmes of his own. The " Research St. George's Chapel, Windsor. heartily second their efforts to obtain Programmes " have earned their name, I DECEMBER 27TH. -Programme composed reasonable representation at the micro- gather, from the amount of research by A. J. Alan. DECEMBER 28TH. -" Montezuma," a play phone. Their best course will he to con- which goes to their compilation. by C'. A. Lewis. tinue the fusilade at frequent intervals; Among recent examples of this form Daventry Exp. (5GB). only their own sturdy efforts will prevent of entertainment have been " Love " and DECEMBER 23RD.- Excerpts from Bach's the main station from gradually assuming by L. de G. " Christmas Oratorio." " Kaleidoscope," both DECEMBER 24TH. -"The Do -Drop Inn," a entirecontrol of the programme material. Sieveking, produced since he left the comedy by Gladys Joiner. 0000 Talks Department. DECEMBER 25TH. -" Dick Whittington." C 000 DECEMBER 27TH. -" MontezUina." Seeing the New Year In. DECEMBER 28TH. -" Out of the Hat," a Musical " Scenery." Christmas Vaudeville Draw. On New Year's Eve listeners will hear There is a growing tendency towards Cardiff. a star vaudeville programme from 2L0, DECEMBER 25TH. -" Upon the Midnight 5XX, and other stations. this drama - cunt - music - cum. - literature Clear," a Christmas Evening in a form of broadcast in the B.B.C. pro- Welsh Village, by Vaughan Thomas. The artists are expected to be the Trix and one assumes that here the DECEMBER 26TH. -" Hüusel and Gretel," Sisters, Neil Kenyon, Jack Strachey, grammes, u fairy opera by Adelheid Wette. Corporation is following the demands of Madge Kennedy, and Violet Essex. The Manchester. programme will wind up with reminis- listeners. The idea is, partly, to give DECEMBER 24TH. -" Scrooge," adapted musical " scenery " to atone for the lack from " A Christmas Carol " (Charles cences entitled " Songs we used to sing." of legitimate stage furniture. Dickens), by J. C Buckstone. Finally we shall hear Mr. J. C. The results are often successful, but Newcastle. Stobart's " Grand Good Night," which is DECEMBER 27TH. -" King Midas," an now a event in the annual several listeners of my acquaintance con- operetta. regular is Glasgow. calendar. fess that music, of whatever kind, 0 0 C C DECEMBER 25T11. -" No Room at the always too obtrusive to form a mere back- Inn," a Christmas Morality Play by ° 24 -Hour Time." ground ; they cannot give complete atten- David Cleghorn Thomson. " tion to the spoken word so long as there DECEMBER 28TH. -" Gor Ain Fireside," If the plea of the Astronomer Royal - a Scots Christening. is a fragment of a tune in the offing. for the general adoption of " 24 -hour 0000 Aberdeen. - time " meets with success, one of the first DECEMBER 25TH. -A Scottish Feature Pro- things will Task. gramme. evidences of the new order of A Busy Belfast. appear in the broadcast programmes. As dramatic producer for several DECEMBER 24TH. -' Christmas Eve in many of the Continental has prepared more Ballymulcaghey." Already years, R. E. Jeffrey stations use the 24 -hour clock, so long - than fifty plays for broadcasting and has distance listeners will have no difficulty in himself written six, the most noteworthy representatives of the accommodating themselves to the new of which was " Speed," produced about Education, and As for DX enthusiasts, Chamber of Commerce. conditions. six months ago. 0000 " ack emma " and " pip emma " have In view of forthcoming developments long vanished from their vocabulary. in "Research Programmes," " R.E.," as Drawbacks to Group Programme System. oo00 he is familiarly known, is likely to be All these gentlemen protested against very busy indeed. the new dispensation which would turn Heartache. 0000 6FL into a mere mouthpiece for the I hear that there is already a certain A Deputation `rom Sheffield. Manchester station. Sheffield, like amount of heartache over the prospect of It the importance of broadcasting in Liverpool and Hull, is suffering from leaving " the precincts of the Savoy." the modern scheme of things required the group programme system, which cen- In many respects the place is ideal for A 4f

www.americanradiohistory.com DECEMBER z9th, 1928. WIp@hoo WoyIlcl 833 broadcasting headquarters. The heavy period for broadcasting was traffic of the Strand is three - Pianoforte AccompanimeLt. well out of ear- quarters of an hour. What happened shot, and even the Embankment, with its Whereas, in the trams was that listeners were cut off in the old days, pianoforte and other heavy vehicles, is midst of his accompaniments in the studio separated from sins. were too Savoy Hill by the pleasant o00o soft, they are now too loud, and the Embankment Gardens. result is unpleasant flatness a Interrupted Speeches. except when If portion of the present building the singer is " swamped," as were not in It is surely a debatable often hap- the honourable occupation of point whether pens. The result is as unfair to the the Institution of Electrical Engineers the the B.B.C. should undertake the broad- accompanist as to the singer. new Broadcasting casting of speeches which In House would un- are likely to be most outside halls, however, the doubtedly have been built on the Savoy interrupted before their conclusion. To " stereoscopic " listen effect is at once evi site. to a speech without hearing the dent. The piano is heard 0 0 0 0 conclusion as a member is often a pure waste of time. of the audience hears assertive Not always, of course. at it- enough A Misconception. the right moment, but always sub- servient to the singer. In occupying " Broadcasting House " as ordinary rent -paying tenants, the 0000 B.B.C. will be creating no precedent. Sanctity of the Studio The present building at Savoy Hill is If the B.B.C. wish us to proper retain a Crown property, coming under the estate respect for the sanctity of the of the Duchy of Lancaster, and the rent studio they must really give up outside paid by the B.S.C. is, it will be noticed, broadcasting, or do something to spoil in Recent it. the annual revenue account. " O.B.s" have been so good as to During recent constructional altera- put many of the studio performances into tions at Savoy Hill the sudden appear- the shade. ance of the Royal Arms over the main 0000 entrance suggested to many people that a A Maeterlinck Play. final touch was being given to the On January 3rd Maeterlinck's "official " nature of the B.B.C. As a symbolic matter play, " The Sightless," will be broadcast of fact, the Royal Arms merely from 2L0 and indicated the ownership 5XX. It will be preceded of the building by ezp!anatory notes. and bore no relation to the activities of 0000 the tenants! 0000 Scottish Group Programmes. Aberdeen is providing a programme A Prince as Soloist. all for Scotland on January 2nd. This is one At the National Sunday League concert of the first Scottish " group to " pro- be broadcast from the Palladium on grammes which 2BD has put on under the January 6th, Grieg's Piano Concerto will new scheme. The programme be played includes by Prince George Chevchevadzi. songs by Lawrence A. Morgan, a Glasgow The new Symphony Orchestra is to be tenor, violin solos by Alec conducted Nicol, reels by Dr. Malcolm Sargent. and strathspeys played on the mouth organ by Donald Davidson, and selections by the Station Octet. A feature will be Mr and Mrs. O. Listener. the duet arrangements of Scottish songs sung by two On New Year's Eve, Belfast is to broad- well -known Edinburgh cast some " Reminiscences singers, Marion Richardson and Dorothy of 1928," in King. which Dir. and Mrs. Ordinary Listener There will also be a short Scots will spend an hour réviving comedy sketch by Rae Elrick called memories of " The Finishing those programmes which have given them Touch." the most enjoyment during the past year. 0 O O O Symphony concerts, variety, opera, plays, A Distinguished Listener. and running commentaries will pass in The 'Talks Department ghostly procession as the magic of the are confident that their listeners are growing in num- microphone evokes their shades. bers 0000 and that many eminent people are included among the supporters of the For Older Children. present talks policy. Sir Maurice Amos, L. de Garde Peach's fantasy, who recently gave a " The talk on Egypt, was heard by Sir Austen Charcoal Burner's Son," was one of the most successful Chamberlain, and on the following day Children's Hour features received a telephone message of 1928. There have been many asking if demands he would call and discuss the subject with for a repeat performance, and the B.B.C. the Foreign Secretary. proposes to meet them by including the O O 0 O fantasy in the evening programme on January 4th, so that the elder, as well as A POPULAR STATION. A striking Letters to Talkers. of the masts view the younger, children may hear it. The at Hamburg. The station Many broadcast speakers receive cast will include can be heard nightly on 394.7 metres. dozens members of the B.B.C. of letters from listeners, and it, is only staff. by chance 0000 The Swing of the Pendulum. that news of these percolate through to Savoy Hill. Sometimes In the days of the the A Shavian Joke. old carbon micro- B.B.C. only learns of the fact when a phone there was no need for Sir Harry I wonder how many speaker, in a subsequent talk, mentions talkers other than Lauder's wet towel device to damp out how many George Bernard Shaw would have letters he had received in re- been the accompaniment. The soloist had the gard to his previous effort. allowed to tantalise listeners as he did field to himself, and if the accompani- on December 7th? He Few letters are forwarded to speakers spoke at the ment leaked through with any precision c/o B.B.C. In most Royal Academy of Dramatic Art for cases, listeners are it was a sure sign that the singer was (a; enthusiastic enough to hint up the ad- more than an hour, though we may prolonging the pauses, (b) getting assume that tired, dresses of the talkers and send their letters he was aware that the allotted or (c) suffering from laryngitis. direct. A 47

www.americanradiohistory.com i .sï.át:r it..rC141 wang DECEMBER rgth, r928. 834 warm USEFUL DATA CHARTS. (NO. Lgo STAGE o) Resistance. Diameter of Wire or Strand to give Coil of Minimum H.F. summarised above are carried out in HE theory involved in designing coils of minimum The operations layer, three stages. Stage i, which accompanies this article, H.F. resistance, whether single or multi- will his results gives P2 for solid wire coils. Stage 2, which T has been given by Butterworth :1 n2P2 the next useful data chart, will give v + be expressed as follows appear as may :- for stranded wire. Stage 3 will finally give d. Let L = self- inductance of coil in microhenrys. scales Fig. 2 shows the extended abac using equal S = a shape factor.2 easy for 1 whose scale is immaterial): it is D = diameter of coil. (except /D, I= frequency in cycles/ sec. d= diameter of wire or strand required. t D P`' n = number of strands. I D L S2 Q = a number depending on n. Then for solid wire coils a quantity P2 can be calcu- lated such that P2 =LS2 / D'. is then given connecting f /P2 and Pd so A curve lo" that Pd can be read off and d revealed. lÓ 2Ó ló

S, and D Fig. 3. -Here the scale unite have been altered so that L VALUES OF S can be read off directly. P2 = LS2 / D3. Note that D2 is not mid- D o 0.125 015 0375 05 to verify that way between L2S4 and r /1'2, which position would require a special scale for D2. In Fig. 3 the scale units 0 have been altered so that S, L, and D can be read 01 3 01 off directly, and Fig. 4 is obtained by folding Fig. 03 in three, using S and LS2 as hinges. S and LS2 are no 0.4 lines. Pd 05 longer required, and disappear into reference P2 -L S2/D3 The Shape Factor Curves. These have been plotted for a single -layer solenoid and for multi-layer coils whose ratio of thickness to mean diameter ranges from zero to unity. In the case and of t /D =o.o5, t /D =o.i, each curve shows a kink, the short arm of the curve merges into the curve for //p2 its t / D = o, and coincides with it for the rest of course. of wire 200 microhenrys is wound to Fig. 1. -Chart by Butterworth giving the best diameter A single -layer coil of or strand. a length of 2in., and its diameter is 4in. We start When stranded wire is used, P2 must be replaced at the point t /D =o.5, draw a tangent to the curve by v + n2P2, and the curve used as before to find Pd and d. d now means the diameter of a single strand. lD L D P2

ló L D2 2

three, using lÓ 5' 5' 5' 5' Fig. 4. -This diagram is obtained by folding Fig. 3 in 5' 8 and LS' as hinges. marked " single layer solenoid," and after pássing scales are used Fig. 2. -The extended abac is here shown: equal L and D we obtain P2= 0.044. except for I,D, whose scale is immaterial through A multi-layer coil has L= 20,000 microhenrys, mean Butterworth puts D= outside diameter of coil, but diameter = loin ., length = ioin., thickness = loin . Hence for graphical computation it is better to use the mean s /D= t /D =rm. We obtain finally P2= o.ro5. calculated on next published abac, is diameter : the values of S have been re- Stage 2, which will be the this basis and have been extended over a greater range. only necessary when stranded wire is used. When P2 has been found by Stage for a solid wire coil, Stage 2 1926, pp. 754, 811. replaces I The Wireless World, Dec. 8th, 15th, enables us to find the value of a. + n2P2, which : (a) of axial length to 2 Depending on two quantities ratio Pa. R. T. B. (b) ratio of radial thickness to diameter of coil. diameter of coil; A 48

www.americanradiohistory.com DECEMBER rgth, 1928. Wpesoo WamIld 835

0.0005 0-0008 0.0008 0-001 OE7Mtlt7U OE7M1E7III7 00015 0.02 ÓnÓÓVCM115.0c91c.a 0.002

0'003 003 0.004 0005 0.008 0'04 0.008 30.000 0.01 0.05 20.000 0.015 008 15.000 007 0.02 008 10.000 MEAN DIAMETER OF 0-03 8,000 009 COIL IN INCHES 0.04 01 6.000 -= 5,000 005 0.08 4 000 Fo 0.08 3.000 -_ =7 015 01 =8 2.000 SINGLE LAYER 015 02 1,500 SOLENOID 02 yto 1,000 = z 800= 03 w = 0-3 04 0= 80. 2 500 05 Ó 0.8 04 0.8 300 = ID -0 1 0.5 MANY LAYER 200-3 SOLENOID 08 1.5 150 ' = 15 07 2 100 0.8 1/D'0 1 09 80 14D-0-05 1 80 50- 5 40 8 30-5 8 I-5 10 20-5 15 IS - 20 10- 30 40 50

80 -100

150 200

DIAMETER OF WIRE TO GIVE COIL OF MINIMUM H.F. RESISTANCE 300 400 STAGE I DETERMINATION OF P2 FOR SOLID WIRE

W.W. A8A0 I N° 19

STAGE 1.

A 49

www.americanradiohistory.com WIpds@g DECEMBER 19th, 1928. 836 WazIl4 WIRELESS WORLD Lim ORATOR\ TESTS

f

A Review of Manufacturers' Recent Products. able to lay their hands on a spare lamp H.F. CHOKE. is 2,650; in the average receiving circuit IGRANIC be higher and it when a fuse has satisfactorily performed is wave -wound the resonance would Bui- The wire in this choke assume that self- oscilla- its special function. Messrs. H. F. looks like a minia- would be safe to and the finished coil tion due to the choke would not occur ture edition of a honeycomb plug -in tun- is low and below 3,000 metres. ing coil: The D.C. resistance The winding is completely enclosed in the impedance curve indicates that the provided with lower than the a moulded bakelite case H.F. resistance is also terminals and a moulded foot for base- board mounting. o 0 _ o " BULGIN " SAFETY FUSE HOLDER. As it is now possible to obtain small bulbs of the " flash lamp " pattern which " blow " at a very low current, the em- ployment of these as safety fuses in H.T. circuits is becoming more general. Hither- to the advantages conferred by fuses of The Bulgin safety fuse holder. Provision this type were more imaginary than real, is made for a spare fuse lamp. unless, of course, the receiver was fitted - Co., foreseeing this difficulty, with a sufficient number of valves. Those gin and and fit have produced a fuse lamp carrier, with who folio .v the safety -first policy if time or other, have accommodation for a spare lamp, and fuses must, at some loaded it will never experienced the annoyance of not being these are always kept

400.000

RANIC = M.F. OHOKE i Igranic H.F. choke ; D.C. resistance, 239 ohms. ' 300,000 :=:::::: ..p.. M average. The curve approximates more Ñ . closely to the form of tuning curve to EC.iEME E EE M which we are accustomed,. more particu- IÍI'I'PiI'IIi:IF!'1I'1ÌF larly at the base, which is flatter than :::C:MC= C _': CC:: usual. This means' that the choking MUM _ effect as more evenly distributed over E Mr.E M MM MEE the 200-500 metre band -a property MMI reaction which should tend to give equal ss:C: _:: Ç::: :M.M. over- this band if the reaction coil and 100.000 E . EC EEM feed condenser are suitably chosen. -E=ES M C . The impedance values at- varions typical _ are as follow -M E CM;; wavelengths :- E i (ohms). iE Wavelength (metres). Impedance o 2,500 3000 34100 200 8,500 .500 ló0 0 1ß0 0 21)00 12,000 500 WAVELENGTH (METR ES) 1,600 136,000 With 8 micro -mfd. external capacity 8 micro-mfd. Impedance curve of Igranic H.F. choke; external capacity across the choke the resonant wavelength Aso

www.americanradiohistory.com AlliiikrONi^C4W4Rt : lCi!7K!tVR+i.s?31 :1 r:+r.o-a"rinelirMlllIrrlf

DECEMBER 19th, 1928. WApasoo. WUAcI 837 be necessary to endanger the valves by medium -wave coil. These are marked in the back operating the set without adequate safe- Al to accommodate terminal and A2, and are intended as alter- strips for aerial, earth and battery guards. native aerial connections. leads. Used in con- The price of the cabinet as illustrated is The price of this useful component is junction with a standard P.M.G. aerial Is. 3d.. without 32s. 6d. fuses, and the maker's (about 100 ft. of wire) and connected in The address is 9 -11, Cursitor two loud speaker cabinets measure Street, Chan- shunt with a 0.0005 mfd. variable con- 12 x 12 cery Lane, London, E.C.4. denser, x 8in. and 10 x 10 x 6in. respectively, the medium -wave coil tunes from the former having 0000 about 265 metres to a circular ornamental 600 metres, and with grille loin. in diameter and the smaller A NEW TWO -RANGE AERIAL the loading coil in circuit from 1,200 to TUNER. 2,000 metres. '4in. In both cabinets the apertures are Although the two ranges covered with tinsel attached Messrs. R.I. and Varley, do not overlap, the blank portion should to the inside. Ltd., have These are ideal for the home construc- long specialised in all -wave tuning de- not be noticed, as there are so few broad- vices, cast tors' use ; the larger size, which costs and the latest addition to their stations working between 600 and 15s., wide range of 1,200 metres. is suitable for mounting moving -coil components is an aperiodic type of loud speakers, The tuner is designed for single hole and the smaller is fixing, but a small hole should be drilled in the panel to take the positioning pin protruding to the rear of the dial. The function of this is to hold the dial cover rigid and prevent this rotating when adjusting the reaction coupling. Each carton contains a book of instructions which explains fully the method of mounting the turns and the connections to the various terminals. In addition, some very useful circuit diagrams have been included showing the many uses to which the device can be put. The tuner is a product of Messrs. R.I. and Varley, Ltd., Kingsway House, 103, Kingsway, London, W.C.2, and the price complete Two loud speaker cabinets by S. A. Smith. is The larger of the two is suitable for 25s. housing a moving O O O 0 coil loud speaker. A NEW PYE TRANSFORMER. perhaps more suitable for fhe reed- driven An output transformer designed cone type. The price of this in specially for use in sets fitted with a mahogany, oak or teak is 10s. 6d , and pentode output valve has been put into the mak ;rs are Messrs. S. A. Smith, 159, production by Messrs. W. G. Pye and New Kent Road, London, S.E.l. Co. The secondary winding has been ar- 0 0 0 0 ranged to suit the average medium im- HAY'S RADIO WAX. A two -range tuner, an R.I. and Varley pedance loud speakers, and best results product. will be obtained under these conditions. This is a compound specially prepared The for wireless purposes and is ideally aerial tuner. This price of this new component is consists of a paxolin 20s., and the maker's suited for sealing fixed condensers after tube 3iu. in diameter and 5in. address is repair, or long, " 1ranta " Works, Montague Road, to protect exposed metal parts carrying two coils spaced about 1 in. of accumulators or wet batteries again# apart and protected Cambridge. by celluloid strips. U O C O corrosion, due to creeping of the elec- Normally the two coils are in series, but trolyte. Its melting point is between - a switch is fitted to short -circuit one coil SMITH'S CABINETS. 125° and 1300 F., so that it will not melt for reception on the medium broadcast The three cabinets reviewed all exhibit or become soft at normal atmospheric wave -band. This is mounted on a very fine workmanship and finish. The temperatures. As it is an excellent sub- moulded Bakelite box cover, which pro- receiver cabinet accommodates a panel stitute for paraffin wax, and, moreover, tects also the various wires connected to 26in. x8in., a baseboard 8in. in depth, and being black imparts a more workmanlike the switch. has an ornamental front with an oval appearance, the experimenter The reaction will find coil is wound on a former shaped opening measuring approximately this a very useful addition to the work of smaller diameter than the outer tube, 12in.x61in. across the major and minor shop equipment. and can be rotated through 180 °. This former is carried on a spindle passing through the centre of the switch arm and terminating in a small, slow- motion dial. The driving knob is fitted on the right - hand side of the dial, and not below as is usual in reduction drives. The object of this is to leave the lower portion free from obstruction to accommodate the arm actuating the wave change switch. The upper portion of the dial cover is cut away, forming a window through which can be seen the graduation on the ivorine scale, and to facilitate accurate adjustment a fine hair line has been fitted on the celluloid inset covering the window. Six terminals are fitted on the large Smith's receiver cabinet with ornamental front. former, two being connected by flexible leads to the reaction winding, one to each axes. It is fitted with a hinged lid and The makers outside are Hay's Marine Water end of the tuning coils marked a removable back. This slides upwards proof Glue Co., Ltd., 6, Surrey " G " and " Street, E " respectively, and the re- in grooves . cut in the sides. Two rect- Portsmouth, and the price is -small size maining pair go to tappings . on the angular- shaped openings have been left tin 6d., llb. size 2s , and 71b. tins 7s. 6d. A 51

www.americanradiohistory.com DECEMBER 19th, 1918. 838 WAygsgo TAKmDc1

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The Editor does not hold himself responsible for the opinions of his correspondents. and address. Correspondence should be addressed to the Editor " The Wireless World," Dorset House, Tudor Street, E.C.9, and must be accompanied by the writer's name TELEVISION. learn anything from its foreign rivals (from the technical Sir,-I overlooked the letter from Mr. E. J. Crampton, side, anyway !). which appears to have inspired replies by two correspondents. Furthermore, I firmly believe that some of the ardent advo- I am compelled, however, to reply to " D.A.T." and Mr. cates of the elimination of " control " are going to get a bit McDowell in your issue of November 28th. The former says : of a shock when they are actually confronted with the problem " The B.B.C. have no axe to grind by their recent ban on of trying to receive in their living rooms a non -controlled piece television, and are merely acting in the interests of the of orchestral rendition. I got an actual taste of such a trans- listener "; the latter almost offers the same argument. mission not so very long ago from a German station, or, at non as the But how do they know that ? The B.B.C. have not said why least assume that it was practically " -controlled," they rejected television, and, in view of the methods employed same question is agitating part of the listening public here. in the turning down of this twentieth- century wonder I take The result was that to bring " pp " passages up to audibility leave to doubt that all the representatives who visited the the whole volume level had to be brought up to a point Baird laboratories were unprejudiced. where it was simply impossible to stay in the room with the After all, what it conies to is this. For reasons best known " f f " passages, to say nothing of the fact that a valve of to themselves, and certainly not to me or the multitude of the transmitter class with about 400 v. on the anode had not amateurs who read 'l'he Wireless World, the B.B.C. granted a chance of handling the input. So the only result of that little facilities to wireless pictures which they withheld from tele- experiment, so far as I was concerned, was that I had to do vision. If the same chances are afforded television as were the " controlling " at my end instead of someone else doing afforded wireless pictures, and if the same results accrue, then it for me at the transmitting end. we who support Mr. Baird will have nothing to grumble at. With the notable exception of the Kallundborg transmitter As it is, we certainly feel a definite grievance, and do not pro- and perhaps Warsaw, Vienna and Budapest, I know of no B.B.C. decision, with the rather strange air station in my reach that can compare with the British Broad- pose to accept the If any of mystery and suggestion of intrigue which is behind il,. casting stations in the quality of the transmitted music. will for world of amateurs, and not the B.B.C., to readers want to hear some real land line distortion I can It be the such as what is in television. The attitude of The only suggest to them to tune in on a transmitter decide there from some distant city, Wireless World in the matter is reasonable enough. Königswusterhausen on a broadcast S. A. MOSELEY, such as Leipzig, when they will hear more humming, buzz cross -talk in five minutes than the B.B.C. would 26; Charing Cross Road, W.C.2. Television Press, Ltd. and telephone let loose on its public in a year. Hence I, for one, am willing to hand the B.B.C. a bouquet CARDIFF HETERODYNED. in lieu of heaving a brick. F. L. B. Sir, -Can you use the undoubted influence of your valuable Danzig, paper to expedite the removal of the awful heterodyning of December 3rd, 1928. the Cardiff Station ? Every evening from 6 o'clock some station interferes and provides a continual background to Cardiff re- ception. Then at 8.30 starts such a howling and whistling that PICTURE BROADCASTING. it is hardly worth listening to the local broadcast. This latter Sir, -I am sure that the majority of listeners will agree station is, I believe, Algiers. with Mr. E. J. Crampton's remarks in your issue of Novem- The Brussels laboratory published a chart for August showing ber 14th regarding picture broadcasting. how the Algiers wavelength has dropped to that of Cardiff. At the moment there is a certain amount of novelty in this Letters to the B.B.C. elicit an expression of regret and an new venture, but the B.B.C. will find that it is only of pass- assurance that " Everything possible is being done." Surely ing interest and that, barring adolescent enthusiasts who only some remedy could have been found since August? play at science, many people will not consider the advantages, Your help will be greatly appreciated, and if this letter such as they are, worth the extra expense and trouble. And will" only tempt you to use your good offices I shall be very how meagre these advantages are ! Who wants pictures that pleased. CYMRO. can be obtained, as Mr. Crampton says, for a penny a dozen Cardiff, in the evening papers? There are very few outlying districts December 5, 1928. with the means for installing and operating a picture -receiving apparatus that are not served by a newspaper service. In TRANSMISSION QUALITY. addition to this, I believe I am right in saying that, under received are by no means per- Sir,-Different letters under the above heading appearing in the process used, the pictures very much of corre- manent. your highly esteemed paper remind me is comparable to receiv- years ago in an American magazine The receiving of pictures by wireless sponsience appearing some on gramophone records when; of " Brickbats and bouquets " -with bouquets ing the ordinary programmes under the heading the matter transmitted is purely of an for the B.B.C. far and few between. as is often the case, the Daventry stations ethereal nature without any secondary interests attached to At a distance of nearly 1,000 miles from would not be required aware of being unable to judge the justness Of some it. Admitted that permanent pictures I am fully but why go 'to the expense of recording of the criticism levelled at the transmission quality of these in the circumstances, however, that at times 5GB comes through a semi -permanent picture by means of expensive apparatus stations. It is fact, and will not be available well that I doubt whether it could be better received when television is bound to -come here sc only have the existing picture -receiving even in the more distant points in England. At such times to listeners who better than most of the stuff apparatus. the quality is so noticeably B.B.C. came to the on the air " by the rest of the European inferno that Therefore I. consider that when the " put took the Wrong turning. Television I cannot understand anyone suggesting that the B.B.C. could parting of the ways they A 52

www.americanradiohistory.com DECEMBER 19th, 1928. " p@Ilsoo 839 WorlIc1 may be a rough and practically nntrodden path, but it is the Meantime they are spending their energy right way for the and resources on march of progress; picture broadcasting altering and rearranging stations in England where a fairly is a cul-de -sac. Radio developed wonderfully when broad- satisfactory service is at present in existence. casting began, so will television. Pictures of news events, Why should they not take Aberdeen in hand crossword at once and puzzles, and the latest fashions are nothing by com- increase its power to, say, 30 kW, and enable it to hold its parison with the wide field this would open up. own amongst the foreigners? Though I do not for a moment think that television will Even if 5XX were free from interference, we should like to reach perfection in any of its present forms, I regard the have a Scottish programme as an alternative at times, par- action of the broadcasting authorities in choosing stationary ticularly from 8 to 8.30 p.m. on Tuesday evenings. pictures in preference to moving ones as a waste of their time I think the B.B.C. would be better employed if they would and our money. Whatever system they choose they will have concentrate on ensuring a satisfactory service to the outlying to make radical alterations from time to time, so that, it being districts instead of entering on the new service of " picture just as easy to change over to a different scheme, there are transmission." By the way, who provides the necessary funds no grounds for hesitation on the score of economy. Let them for these transmissions? start at once and consign picture transmissions to the Press, I have heard the opinion expressed more than once that, the War Office, and such others as have need of them. until the B.B.C. can give a satisfactory service in the outlying Shortlands, Kent. H. A. RAMPTON. districts, the licence fee for these should be reduced. St. Margaret's Hope, Orkney. IAN I. BARCLAY. Sir,-With reference to Mr. E. J. Crampton's letter of the 14th October, in connection with the broadcasting of still pic- tures, which, to use his own words, is wasting the money of CONTROL. the B.B.C. subscribers, may I venture to suggest that this is Sir, -With reference to your notes "A Chat with Control," anything but the case. vide page 481, The Wireless World of October 3rd, 1928, I was If Mr. Crampton will allow his mind to return to the early surprised to know that the B.B.C. has not yet endeavoured days of broadcasting he will find that a lot of very useful to remedy the inefficiency arising from " the difficulty that work was done by amateurs towards the betterment of radio the man at the control can never be sure whether the speaker receivers and reception, until to -day our receiving sets leave will be two, three or four feet away from the ' mike,' and little to be desired. matters can only be adjusted when speech begins." Now I presume that all those people using still picture Prior to the formation of the Indian Broadcasting Co. I receivers are potential experimenters with television and who did a little transmitting for the Bombay Radio Club, when hope at some future date to reproduce on their screen " the mostly gramophone records were transmitted. I used to real thing," and I am sure Mr. Crampton will grant me classify the records prior to transmission in three groups, the that low, real, sound experimental work may be, and is, based upon medium and high, and during the transmission place them these transmissions. Considering that it is only at three specified distances from the " mike " so as to ensure twenty -five even volume with the lot. minutes a day, and the only time the amateur may test his I used to shift the " mike " to adjust ideas in a manner, the required distance from the gramophone. The microphone practical I fail to see any cause for com- used was an plaint. In conclusion, I am certain that the ordinary ordinary Ericsson telephone microphone. If the B.B.C. also resorted to the same strategy in classifying their " listener in " is not given an inferior programme so that these lecturers previous transmissions may be financed. So why to the lecture, and allotted them their worry? " respectful " distance from Rhyl, North Wales. TREVOR R. LITTLE. the " mike," the B.B.C. would help their " blind " control half -way. JOSEPH ALAMS. Bombay. A GRIEVANCE FROM THE NORTH. Sir, -May I be permitted space in your columns to air the grievances of listeners in the North with regard to the B.B.C.'s IS 5GB STILL EXPERIMENTAL P services? Sir, -Surely it is ridiculous for the B.B. C. to insist still In Orkney no British station can be received free from that 5GB is only an experimental station, seeing that they interference. On the 200 -600 -metre waveband reception is ren- have now definitely transferred Nottingham listeners over to dered impossible owing to a spark transmitter station at Wick Daventry Junior for their regular programme s. and also ship stations. No consideration seems to be given Bristol. BM /GEL. by these to the power required to communicate with ship and shore stations as per the P.M.G.'s regulations -they simply A NEW LONDON SHOWROOM. blaze away full force on all occasions. Apart from morse interference, however, 5GB is subject to frequent fading, although stations around it remain quite steady; Aberdeen is hopelessly heterodyned by foreign stations; in fact, at times it cannot be distinguished at all in the din. I have been in communication with the B.B.C. regarding this matter, but they reply that they cannot guarantee a service from any of their main stations beyond thirty miles (5GB 100), with the exception of 5XX. This latter is now at times also hopeless, owing to interference from Lahti, which causes dis- tortion and a loud heterodyne whistle. The German station, Zeesen, also seems prone to wander off its wavelength, as even now, when Daventry's wavelength has been altered, it breaks in at intervals, coming right on top of Daventry and wiping it out. There is also a C.W. morse station which interferes badly at times. The result is that we have no broadcast service here at all which can be relied on. Could not some remedy be found ? We pay a licence fee of 10s. per annum, and for this we receive chiefly morse and the clamour of Babel. The B.B.C. promised to alter Aberdeen's wavelength before this winter season set in, but so far nothing has been done except to talk of a new wavelength of 326.1 metres -20 Kcs. nearer the morse waveband than before and also lying between A PERMANENT WIRELESS SHOW. A corner of the new wira'- two less and electrical showroom of the B.T.H. Company at Crown fairly powerful German stations. House Aldwvch, London, W.C. A 35

www.americanradiohistory.com 1928. 84o WAToIl@go DECEMBER r9th, WopDCI

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" The Wireless World" Supplies a Free Service of Technical Information. The Service is subject to the rules of the Department, which are printed below; these must be strictly enforced, in the interest of readers themselves. A selection of queries of general interest is dealt with below, in some cases at greater length than would be possible in a letter. Reducing H F. Amplification. An Impossibility. blade of springy metal, shaped and Will you tell me of there is any simple For some tone -control experiments which mounted in such a way that it will make way of cutting out one of the H.F. I am carrying out I wish to connect contact with any desired number of studs. stages of the " Kálo -Mag. Four " a single -pole stud switch so that any This will be connected in the manner of in 1. receiver, the idea being to reduce number (up to a total of five) shown Fig. 0000 the sensitivity of the receiver for re- fixed condensers may be placed in cir- ception of the less distant stations. cuit. Will you give one a diagram Momentary Oscillation. N. H R. showing how this may be done? lly H.F.- Bet. -L.F. set works satisfac- torily, notice a curious effect The first amplifying valve may M. M. but I H.F. ordinary on first switching -on; the H.F. valve be cut out of circuit in a very simple It is not possible to connect an switch in the manner you desire, although seems to oscillate for about a second, way by joining the aerial through a con- dies out. to the but this oscillation quickly denser of about 0.0001 mfd. The circuit is conventional, and H.T. socket which connects to its anode. Of is obtained from the D.C. mains course, provision must be made for through an eliminator,. a common breaking its filament circuit when re- voltage of about 120 being applied ceiving in this way, and precautions to the three valves. Can you ex- must be taken against a short- circuit of plain this effect? P. L. F. be intro- the H.T. battery, which would on allowed to touch It seems likely that on switching duced were the socket set voltage applied to your case. the the H.T. the screening valve is considerably in excess of normal 0 O O O value. This may be due to the fact that An Ambitious Project the smoothing condensers in the elimina- Will you please let me lucre a circuit din - tor are charged up to the full voltage of gram of c. " high -power " three -stage the mains, and are not immediately dis- amplifier for radio and gramophone charged, as very possibly the filament of amplification? E. F. J. the output valve does not give ifs full The construction of an amplifier of Fig. 1. -A special selector switch ter a emission as quickly after switching on as this kind is hardly to be undertaken bank of condensers. does that of the H.F. valve. Moreover, is rather too of a condenser lightly, and the subject is, course, easy to arrange it so that apart from the question treatment in a it of is likely to be a consider- involved for adequate any one of a bank of condensers may be charge, there ; diagram, without in voltage when the letter a bare circuit in circuit. For your purpose you able rise eliminator as to valves, components, joined full output is not being taken, as will be information will require a special switch with a wide voltages, etc , is hardly likely to be of the case if the H.F. filament heats more much use to you. If you will let us quickly than the others. have some indication of your requirements RULES. Assuming this explanation to be so far as to output and the H.T. voltage avail- (1.) Only one question (which mast deal with correct, it is quite conceivable that the by a single specific point) can be answered. Letters an excess able we can probably help you giving must be concisely worded and headed " Infor- H.F. valve will oscillate with a reference to a back dumber. mation Department." H.T. voltage, particularly if you adopt (2.) Queries must be written on one side of usual expedient of operating it oono drawn on a separate the very the paper, and diagrams in deneutralised condition, in Rebuilding Variable Condensers. sheet. A self- addressed stamped envelope must a slightly the total number of be enclosed for postal reply. order to obtain maximum sensitivity. If I remove half (3.) Designs or circuit diagrams for complete 0000 moving plates in my 0.0005 mfd. receivers cannot be oiven ; under present-day variable condenser, will its maximum conditions justice cannot be done to questions The Megavox. capacity be reduced by this altera- of this kind in the course of a letter. Will it be in order to use a suitably (4.) Practical wiring plans cannot be supplied in the tion, and will it be less efficient than or considered. designed output transformer before? D. R. P. (5.) Designs for components such as L.F. " Megavox Three" instead of the etc., cannot be altered in this way will chokes, power transformers, choke filter output arrangement which A condenser supplied. in the original design? have approximately half its original (ß.) Queries arising from the construction or was included capacity, and its efficiency operation of receivers must be confined to con- J. C. S. maximum structional sets described in " The Wireless is quite per- should not be impaired. The modifica- Yes, this modification World " or to standard manufacturers' receivers. choose a transformer tion must be carefully executed, how- Readers desiring intimation on matters missible ; you must of a bank of beyond the scope of the Information Depart- specially designed for a pentode, and ever, as the reassembly to submit suggestions regarding more difficult than ment are invited having a secondary approximately vanes is often rather subjects to be treated in future articles or windings. would appear at first sight. paragraphs. matched to your loud speaker A 54

www.americanradiohistory.com ,TheW AND RADIO REVIEW 0164.41.f g¡j (16 f" Year of Publication)

No. 487. WEDNESDAY, DECEMBER 26TH, 1928. VOL. XXIII. No. 26.

this new means of simultaneous communication with all Editor: HUGH S. POCOCK. parts of the country. In this connection we can cite the Assistant Editor: F. H. HAYNES. instance of the broadcasting of the Service of Remem- Editorial Offices: 116 -x17, FLEET STREET, LONDON, E.C.4 brance at the Cenotaph on November irth as of outstand- Editorial Telephone: City 9472 (5 lines). ing importance. Until this year permission to broadcast Advertising and Publishing Offices: this service had been consistently refused by the authori- DORSET HOUSE, TUDOR STREET, LONDON, E.C.4. ties, probably for the reason that it was feared that such Telephone: City 2847 (13 lines). Telegrams: Ethaworld, Fleet, London." a step would detract from the solemnity of the occasion. COVENTRY : Hertford Street. Telegrams: "Cyclist. Coventry." Telephone: 5210 Coventry. But experience has surely proved that, far from this

BIRMINGHAM : Guildhall Buildings, Navigation Street. having been the case, the effect of broadcasting was to Telegrams: "Autopress, Birmingham." Telephone: 2970 and 2971 Mid and. make the Remembrance Service a more important event MANCHESTER : 260, Deansgate. in the life of the nation than had been possible in previous T.legrams "Tillie. Manchester." Telephone: 8970 City (4 lines). PUBLISHED WEEKLY. years. Subscription Rates : Home, 175. 4d. ; Canada, 17s. 4d. ; Opposition to broadcasting has been overcome in a other countries abroad, 19s. 6d. per annum. number of other directions, and it is particularly exempli- Entered as rieeond Uses Matter at New York. N.Y. fied in the improved relations between the broadcasting As many of the circuits and apparatus described in these pages are covered by patents, readers are advised, before malting use of them, to satisfy themselves authorities and those who cater for general public enter- that they mould not be infringing patents. tainment through the medium of the stage or the concert hall. Permission for the broadcasting of controversial CONTENTS OF THIS ISSUE. matter, at the discretion of the B.B.C., has also taken PAGE practical form during the current year. Whether or not EDITORIAL ...... 841 TALKING FILMS, No. 2-THE BRITISH ACOUSTIC SYSTEM .. 842 the decision, and the way in which ,the permission has HIGH-FREQUENCY RESISTANCE (CONCLUDED). BY A. L. M. SOWERBY 845 SWITC'11NG OCT AN L.F. STAGE ., 849 been interpreted, has proved a success is probably even CURRENT TOPICS ...... 850 more a subject of controversy than anything which has NEW APPARATUS . 852 T E NEW EMPIRE RECEIVER. BY H. F. SMITH 854 been broadcast up to date, but nevertheless the experi- PROGRAMMES FROM ABROAD.. .. 860 USEFUL DATA CHARTS : No. 19, STAGE 2 . . 864 ment has been tried, and that in itself is a new BROADCAST BREVITIES ...... 865 achievement. READERS' PROBLEMS ...... 867 Technical Progress. On the technical side, in addition to a general improve- BROADCASTING IN 1928. ment in the quality of transmission of some of the r-riHE close of the year is a fitting time to look back stations, we have experienced several ambitious experi- upon the progress which has been made in the ments in the direction of re- broadcasting distant transmis- development of broadcasting in all its aspects over sions and linking up our own transmitters by land -line to the past twelve months, and whilst congratulating our- the Continent. These attempts have, in general, been an selves on what has been achieved in this country, we improvement on former trials, and we may look forward should at the same time look forward to that which re- to this aspect of broadcasting becoming of greater im- mains' to be done in the New Year, in order not only to portance as time goes on. The regional scheme and alter- make good any shortcomings of the past, but also that native programmes have made progress during the past we may welcome 1929 with the determination to make it year. With the stations at present available the principle an outstanding year in the record of broadcasting of regional programmes has been in operation for some progress. time past, but will not, of course, take effect in complete It has been suggested that in wireless generally the form until the proposed new regional stations are ready. present year has been one of consolidation rather than Substantial progress has been made towards the con- initial achievement of outstanding character, and prob- struction of the regional station intended to supply ably this is an accurate general summing -up, although London with its alternative programme Under the scheme, certain events of outstanding importance must not be but we must wait until 1929 before this station can be in overlooked. operation. Much has been done to consolidate the position of In the direction of short-wave broadcasting by our own broadcasting generally, al :1 it has come to be recognised station we are afraid that little progress has been made, more and more as a factor in our daily life. Old pre- but we hope that the development of this service and judices are giving place to a recognition of the value of many other important new activities await us in 1929. B 11

www.americanradiohistory.com WAT®Ilsogi DECEMBER Woy 11 26th, 1928.

BALKING FI L

No. 2.- The British Acoustic Film System.

N the method used by the British Acoustic Films, two films are employed, one for the ordinary pictures and one for the sound record, and both in recording and reproducing these films are run in synchronism. The process of recording involves the conversion of sound variations into electrical current variations with the aid of a microphone. These electrical variations are amplified in the recording amplifier and the resulting currents passed through the element of a special oscillo- graph which carries a tiny mirror that is turned about a vertical axis, the movement being proportional to the current flowing through the element. A source of light

FILM MIRROR SOUND -- M - AMPLIFIER

Fig. *.../mauffsom.: ° . . 1.- Schematic diagram of the recording system. Sound 1s :r.... converted to electric vibrations by a microphone M and amplifier, and a separate film records the light fluctuations which are Illt- :CCJUST=_ F1Lt4{ES produced by means of the oscillograph O. in the form of a thin straight filament is used and the light reflected by the oscillograph mirror after passing through suitable optical condensing arrangements falls on to the surface of a moving sensitised film as shown in Fig. i. The reflected light from the oscillograph mirror is so arranged that when no current is flowing (i.e., no sound) just one half of film the is exposed and one together with the illuminating lamp and optical focus- half unexposed. When the mirror moves, the line of ing arrangements ; (2) a light- sensitive cell of special light which is doing the exposing moves more or less construction ; (3) an amplifier, and (4) the loud over the surface of the film, giving a record as shown speakers. in sight the photograph. The " " or " mute " film is The sound film is run steadily and not in jerks like run synchronously with the second film, either by direct the mute film, involving a special constant -speed drive or de- by synchronous motors. vice for the projector. The drive may be direct from the The Reproducing Process. ordinary projector or both projectors may be driven by synchronous motors. The light, after passing through Starting with the sound film containing oscillographic the sound film, is focused on to a selenium cell. record of the sound, the reproducing gear consists of This cell is of very special construction, being in the four main parts, (i) a projector for running the film, form of a slit whose width is slightly greater than the B I2

www.americanradiohistory.com DECEMBER 26th, 1928. W>t

The separate sound film. width of the film. A current is passed through the cell volume control, which is the absolute minimum number by means of a local battery, and the resulting fluctu- of controls that could be used and shows the extreme ations of current through the cell, as the illumination is simplicity of the apparatus. varied by the sound film, are passed To turn now to the relative merits of the through a special filter circuit which effec- one- and two -film methods, it must be tively counteracts the lag of the selenium stated that, firstly, in the two -film method cell by attenuating the lower frequencies in a much larger area of film is available for correct proportion. the sound record than in any other single LINE OF LIGHT The voltage developed across part of the REFL E0TE0 FROM film method now in use, which enables °SOIL LOORAPH filter circuit is applied to the input of the MIRRO R more " detail " (i.e., higher frequencies) amplifier, which, in the case of the smaller to be obtainable in the sound record, so type, is of straightforward design capable that the quality of the resulting sound of giving 3o watts of undistorted A.C. out- should be better than with the single film put to the loud speakers. The H.T. volt- methods. Secondly, the type of film and age for this amplifier is 400. developing technique which has been Photographs of the projector and cell evolved after much research for taking show the actual arrangement used, whilé Fig. 2. -A ti Im on which ordinary cinematograph pictures is in- the light fluctuations Cor- tended to give a comparatively " soft " the illustration of the amplifier shows the responding t o the electric general appearance. The filter circuit is vibrations h ave been re- negative -that is, a non -contrasty nega- incorporated in the amplifier and the only cor ded. tive- whereas for the sound record a very controls on the latter are the loud speaker switch, input highly contrasty negative is required so as to obviate change -over switch (for two sound projectors) and the blurred tones and general lack of the higher audio fre-

The general layout of the amplifier. A filter circuit is incorporated which effectively counteracts the tat of the selenium call. B t;

www.americanradiohistory.com 8¢¢ Varg@Og oIll DECEMBER 26th, 1928. Talking Films. - be almost exact or the sight and sound will be noticeable quencies. With two separate films the two types of r_ega- not together." live are comparatively easy to obtain. As to disadvantages ; for transport double the weight Perhaps the greatest advantage of the two -film method, of film is needed compared with other methods using one however, is the ease with which " cut- ting " may be done. Suppose for any reason a section of a film was not required to be shown -for instance, if the censor objected to it-it is extremely easy to re- move the unwanted section by running the sound and sight films together on a double re- winder, cutting out equal lengths from the two films and then join- ing up the ends again -all of which can be done in a few minutes. With single film methods cutting of a section is by no means easy -where the sound record is on the edge of the film. The portion which synchronises with a given picture is displaced by some inches, The amplifier so that the film must not be cut straight panel. Note the simplicity of control. across if synchronism is to be preserved. In the :ase of film- however one of these methods utilises gramophone a single film with the sound record on gramophone discs, discs which are equally heavy and liable to be broken the cutting of a section is even more difficult. if not carefully handled. There Musical Accompaniment with any Film. is also the need of synchronising the two films, which is a difficulty more apparent than real except It should be remembered when that a certain amount of cut - one of the films- usually the " mute," as it is under ting- although it is a small amount -is involved w ien- more mechanical strain -happens to break, when the ever a film breaks, and also that the synchronism rust two films must be re- synchronised. This latter difficulty, however, can be got over quite simply in practice by having a continuous record of the length of each film that has passed through the apparatus. When the Film Breaks. When one film breaks and a piece is cut out in mending, the corresponding piece on the other film can very easily be found and removed. The breaking of a film, luckily, is not a very common occurrence, and the breakage difficulty involves at least as much trouble with any single film system. A further advantage of the two -film method is that with any given sight or mute film, either speech or an entirely musical accompaniment may be used on the same repro- ducing apparatus simply by changing the sound film - also a musical programme may be supplied with any film if desired. For the Provincial Cinema. It will be realised that the usual musical accompani- ment provided by the orchestra actually at the cinema may in this way be supplemented by any desired musical programme supplied by the separate film -and, further, that the music recorded on the film may be produced in the first case by a really first -class orchestra. The musical programme of the small cinema is often a butt for the humorist; there should be little scope for his wit when synchronous reproduction becomes widely used. In this way the small suburban and provincial cinemas would be able to provide first -class music as well as synchronised talking pictures at quite a reasonable cost. Beyong pu.ting on the second film and switching on the amplifier, the operator has no more to do than The projector with light -sensitive cell and equipment to hardie he the sound film has in showing any ordinary " silent " cinema picture. B i4

www.americanradiohistory.com DECEMBER 26th, 1928. Wpgkoo 845 Wm) Ilc1 HIGH FI?EQ UI2IY RESISTANCE

Loss of Energy Due to Dielectric. By A. L. M. SOWERBY, M.Sc. (Concluded from page 814 of last week's issue.)

WHEN discussing, in the first part of this article, circuit until each plate of the condenser attains the the high-frequency resistance of a coil, the potential of the battery terminal to which it is connected. remark was made that the calculate) losses, all The flow of current will then stop, because the plates of which can ultimately be traced to the copper wire of the condenser are insulated from one another, while with which the coil is wound, make up together some the amount of electricity that flows into the condenser 85 per cent. of the total measured high- frequency before equilibrium with the battery is reached will resistance of that component. The source of the depend on the capacity of the condenser, being greater remaining 15 per cent. , and of the losses due to the if this is larger. parts of the tuned circuits, have yet to be con- other The Conversion of Energy. sidered. Turning our attention to the simplest possible form Suppose now the battery is disconnected ; in that a of tuned circuit, we find that it consists of a coil, with current has been taken from it, it has lost energy, and been transferred to the condenser, its high -frequency . resistance, in parallel with a con- this energy has denser, as indicated in Fig. 4. If we imagine that a which retains it in the form of an electric charge. But high- frequency voltage is induced into the coil, by the energy is not lost ; on the contrary, it is easily coupling it, for example, to a second coil connected recoverable. If, as in Fig. 6, the terminals of the to an aerial, a high -fre- charged condenser are quency current flows joined by a resistance R, round the tuned circuit, the potential difference developing a voltage in its between the two will drive t passage through the coil a current through R, and T L. Since the condenser is this current will last just 1 connected in parallel with long enough to enable the the coil, this high two plates of the condenser T T frequency voltage is to arrive once more at the s° applied to the condenser, same potential. The con Fig. Illustrating the ap- Flg. 4. -A simple tuned cir- and we have to see in what denser is then said to be 5.- resistance shown plication of a steady potential cuit. The ris t e discharged again. from a battery to a condenser. external to the coil ; in actual w a y h condenser fact r is the high- frequency re- responds to this voltage. Thus the energy taken sistance of the coil Itself and the two are not separable.. In case any reader is from the battery during the process of charging the con- vague as to the action of a denser is given up again in the form of an electric condenser, we will digress for a moment to see the effect current when the condenser is permitted to discharge, of a simple direct voltage. and thus no energy is lost. Perhaps a more familiar If, as in Fig. 5, a steady potential difference is applied example of the energy stored in a charged condenser to a condenser, at the instant of completing the circuit and released again by discharge may be found in the we have the two plates of the condenser, which are at spark that may be drawn from a reservoir condenser the same potential, connected to the two terminals of of high capacity after charging it from the H.T. the battery, whose potential must necessarily differ by battery ; a similar manifestation is found when unex- the voltage of the battery. This is clearly an unstable pected shocks are mysteriously received from the state of affairs, so that a current will flow round the interior of a set after disconnecting the source of anode 8 15

www.americanradiohistory.com 846 WfltWs@gi DECEMBER 26th, 1928. %VopIld High Frequency Resistance.- out on discharge than was absorbed during charge. If voltage. All this may be summed up by saying that we compare the charging of a condenser to the com- just as the magnetic field set up in the neighbourhood pressing of a spring we shall have a remarkably close of a coil by the passage of a current stores energy in a mechanical analogy, the insulator or dielectric situated form readily reconvertible into an electric current, so between the plates, and in which the energy is stored, the electric field set up within a condenser by the appli- representing the material from which the spring is made. cation of a potential difference stores energy in another, If the spring is of finely- tempered steel it corresponds but equally reconvertible, form. to the perfect dielectric, returning on release (discharge) all the energy A Mechanical Analogy. absorbed during the compression (charge). But if the spring is made of softer material Now let us apply this to the simple tuned circuit it will take a permanent " set " when compressed, and already mentioned, and shown in Fig. 4, remembering though it will return towards its original form it will not that a high- frequency voltage or current is nothing more completely regain it, so failing to return some of the than its simple D.C. equivalent continually reversing energy expended in compressing it. In just the same in direction according to a simple law. We will arrest way a condenser with an imperfect dielectric does not this rapid alternation at a moment when the current refund on discharge all the energy spent in charging round it, the circuit is at a maximum, with the condenser and in both electrical and mechanical cases the lost uncharged, and will trace at our leisure the succeeding energy appears as heat. stages, which may occupy an extremely short space of time such as a millionth part of a second or less. Losses in Coil Plugs and Formers. The current, then, is flow- It will be realised that the loss ing into the condenser and of energy caused by imperfections of dielectric will not be limited in its charging it up ; as the appearance to components charge accumulates, to which the name condenser the is applied, but will make counter -voltage from the its appearance whenever we R have an arrangement which condenser slows down the in actual fact is a con- denser, whatever may be the name under which it current until finally it chooses ceases, to masquerade. Thus whenever there arises a leaving the con- potential difference denser fully charged between two conductors separated -that by an insulator, there we have is, with an electric field sur- the essentials of a faulty condenser. In the tuning coil, for Fig. 6. -If a resistance is con- rounding its plates. The example, there are nected across a charged con- a number of turns, separated by the insulation of the denser the current through R current now begins to flow will continue until the plates wire and by that of the former on which the coil is of the condenser are in the opposite direction, at the wound ; as the high-frequency current same potential. and while it is increasing flows through the it coil there will be a potential difference is helped by the voltage in between different turns, and this will be larger the the condenser, which discharges itself through the coil further apart the turns just as, in our previous example, are in order of winding. If, for example, the first and it discharged through last turns the resistance. By the time the current are brought to sockets in a plug made of an has reached its insulator which has maximum value again, the charge on the condenser has poor dielectric properties, the losses introduced will be very all been used up, and the energy stored in its electric appreciable indeed, and will form quite a big proportion field during the first part of the process has been of the total high- frequency resistance of the coil. It is clear from this returned to the circuit as current. The same series of that it is essential to choose for the plug of a -in operations is then gone through again, with the sole plug coil, and for the holder that is difference that the current and the voltage to receive it, a material in which are both the dielectric losses are small, and reversed in ; that if the highest direction . we are then back at the begin- efficiency ning of the cycle, at the point where is sought no material other than air, which is we started, and the a dielectric millionth of a second is over. introducing practically no losses whatever, In the case of the magnetic field of the coil we saw that in the ideal case there were no energy losses, but that all the energy withdrawn from the circuit in build- ing up the field was returned to it again as the field collapsed. We also saw that the ideal case could not be realised in practice, but that there were always some sources of energy loss due to the production of unwanted currents in any conductors, including its own wire, that might be within range of the coil. In the case of the electric field set up in a condenser the possibility of losses does not arise through the presence of conductors in the field, but through that of insulators. So long as there is nothing but air between the plates of the condenser practically all the energy absorbed on charging is returned when the condenser discharges, but if is Fig. 7 . -A popular coupling used to connect a screened grid the air replaced by an insulator less energy is given valve to the succeeding valve. a 16

www.americanradiohistory.com WIndsem DECEMBER 26th, 1928. Wait 847 High Frequency Resistance. - used for the purpose is shown in Fig. 9, where the valve must be allowed to intervene between these two points is an anode detector with a meter in its plate circuit ; of connection. this meter indicates by its deflections the high-frequency The odd 15 per cent. of the high -frequency resistance voltage induced into the tuned circuit by the oscillator of a coil, which cannot be accounted for by the calcu- (not shown). R stands for a number of inter- change- lated losses in the wire itself, are due to the dielectric able resistances of fine wire, the values of these resist- losses in the former of the coil and in the insulation ances being known, and being the same, within narrow between turns ; in this estimate no allowance is made limits, for high- frequencies as for direct current, on for plugs or holders for making connection to the ends. which they were measured. The measurements consist In the tuning condenser itself, where the dielectric in reading the deflections of the meter, for a fixed posi- between the plates is almost entirely air, the absorption tion of the oscillator, with each of the resistances R con- nected in turn in the tuned circuit, and plotting a curve connecting the deflections obtained with the values of the resistances. Keeping the oscillator coupling unchanged, the various components to be tested are then connected 11 c in turn across the tuned circuit, and the deflections of ,T° : the meter are noted. Reference to the curve at once 7 gives the effective resistance introduced by the com- ponent in question. '1111 Measurements were carried out in this way with a number of components of different types and different makes, and on a number of different wavelengths, vary- ing from 20o to S5o metres. In all cases the coil was a coil Sin. Fig. 8. -The equivalent circuit of Fig. 7, where each component standard Wireless World Litzendraht on a that Is likely to increase the high -fe equency resistance is repre- paxolin former ; it had an inductance of 259 micro - sented as a conuenser. henrys. The tuning condenser was an ordinary " low - loss instrument of well -known make. of energy due to imperfections of dielectric are truly " negligible ; this component contributes but an incon- Valve- holders. siderable trifle to the high -frequency resistance of the tuned circuit as a whole. Two valve-holders of different types have been But, as already hinted, there are other condensers in selected as examples ; for obvious reasons the names of the circuit in parallel with that used for tuning, and in the makers are not given. Holder A consisted of a these the dielectric is seldom above reproach. In Fig. solid block of (apparently) bakelite containing the four 7 there is given a circuit in common use to -day ; it sockets ; this was suspended by springs in a larger bake- represents the intervalve coupling between a screened - lite block carrying the terminals. It is a thoroughly grid valve and the valve, whether H.F. amplifier or well -made and very popular holder. Holder B had no detector, that follows it. In Fig. 8 the same circuit is repeated, with each component that is likely to increase the high -frequency resistance of the tuned circuit through dielectric losses represented as a condenser, and with the high-tension battery omitted to simplify the diagram. Actual Measurements of H.F. Resistance. It will be seen that across the tuned circuit, in addi- tion to the legitimate tuning condenser C, there are no fewer than seven other sources of capacity, and each of them, owing to the presence of solid insulating material of some kind or another, is a possible cause of serious loss. C1 and C_ stand for the glass pinch Fig. 9.-Circuit diagram of valve voltmeter for measuring and insulating base respectively of V while C, is its relative values of high- frequency voltage induced in the tut ei circuit by the oscillator. 11 represents interchangeable re- holder. C4 is the grid -leak holder, C5 the holder for sistances of fine wire. V., and C,; and C, the base and pinch of this valve. The capacity of each of these components is connected insulating material at all between the valve-legs, except across the tuned circuit, each contains solid dielectric, for a thin shell through which the legs passed to the and each is therefore a potential source of high -fre- four sockets below ; these were supported by the sides quency losses. of the shell. This holder is a cheap one, not very pre- The writer has estimated the resistance thrown into possessing in appearance. The results obtained were the tuned circuit by some of these incidental capacities ; as follows : that is to say, has found the value of the high- frequency - WAVELENGTH of TEST. (Slams.) be resistance that needs to added to that of the coil in .AO 225 250 900 400 560 order to produce the same effect as connecting these Holder A 8.3 5.7 4.2 2.7 1.1 0.5 ohms components across the tuned circuit. The apparatus Holder B 1.0 1.1 0.8 0.5 0.4 0.2 ohms B 17

www.americanradiohistory.com 848 WApg@Og DECEMBER 26th, 1928. WORMoopM High Frequency Resistance.- frequency losses, bakelite might be a less desirable In making the measurements, the plate terminal of material than ebonite, and tests were made on this point. the holder was joined to the two filament terminals, these The writer had no ebonite valve -holders available, three being connected to one side of the tuned circuit and so turned his attention to grid-leak holders. Holder and the grid terminal to the other. This arrangement A was of bakelite, being the beautifully finished product represents the state of affairs in a Moulin voltmeter, in of a first -class firm. Holder B was a shoddy thing, connection with which the measurements were primarily. made of very doubtful -looking ebonite, but being to made. hand was put through its paces. The results were Valve -base Dielectric Losses. these :- WAVELENGTH OF TEST. (Metres.) Two things will at once be noticed from the table 200 225 250 300 400 550 above ; first, that the " better " valve -holder turns out Holder A 1.35 0.85 0.7 0.5 0.2 to be by far the worse from our present point of view, Holder B 0.15 0.1 0.1 and, second, that the effective resistance in both cases The fact that the equivalent resistances introduced by increases rapidly towards the bottom end of the wave- these components was small made the taking of accurate length range covered by the coil used. This latter effect measurements difficult ; there is no doubt, however, is common to all such measurements as these, and is which is the better material. due to the fact that as the capa- It occurred to the writer that city of the tuning condenser is there would be but little point in decreased a greater and greater choosing valve- holders and other proportion of the total high -fre- components with care if the in- quency current flowing has to sulating bases of the valves pass through the capacity of the themselves were likely to intro- component being examined. duce a large equivalent resist- Now the calculated resist- ance ; the stock of valves was ance of the tuning coil with therefore investigated, and it which these valve- holders were was found that one of a pair of in parallel varies with wave- identical valves had a loose length, too ; the values of the base. This was therefore re- high -frequency resistance due moved, and comparison mea- to the copper of the coil, ignor- surements were made with the ing any dielectric losses, a.re as two valves, filament and plate follows :- being in both cases connected to Wavelength. one side of the 200 225 250 300 400 550 mctrr tuned circuit, H.F.R. of coil. while the grid was connected to 5.9 6.0 4.3 3.5 2.5 2.0 ohms the other, just as in the case of The very considerable effect the valve -holders already men- that Holder A will exert on the tioned. The following were the characteristics of the tuned cir- results : - cuit across which it is connected WAVELENGTH OF TEST. (liletres.). will at once be seen, for at all 200, 225 250 300 400 550 wavelengths up to 250 metres it Valve with base. more than doubles the effective 7.8 5.3 3.8 2.5 1.0 0.5 ohms high- frequency resistance of the Without base. Fig. 10.- Curves showing variation of high - circuit as a whole, and even at frequency resistance of complete tuned circuit 1.05 0.8 0.6 0.5 0.25 0.1 ohms with wavelength. Curve 1 gives the result of Difference. 55o metres, where it has least employing normal components with high di- effect, it adds 25 per cent. to the electric losses, while in curve 2 all precautions 6.75 4.6 3.6 2.0 0.75 0.4 ohms to eliminate dielectric losses have been taken. In resistance. And this valve - both cases the coil is ti standard Litz coil of 68 The last line represents the holder is turns on a 31n. former. unfortunately only one losses in the valve -base itself, of seven sources of enhanced high-frequency resistance. while the second represents the losses caused by the These figures throw into strong relief the neces- glass pinch of the valve. Other valves were sity for also exam- choosing valve -holders in which there is ined, and gave results similar to those in the first line the minimum of insulating material between the of the table. It is therefore clear that considerable high - sockets, at least when efforts are being made to keep frequency resistance is introduced into any tuned circuit the high- frequency resistance of the circuits down to across which a valve is connected by the dielectric im- as low a value as possible. Even when extremely low perfections of the insulating compound in which the resistance is not required, the use of such holders ren- legs are embedded. ders the design of a receiver very difficult, for the tuned circuits, when in the completed receiver, will have a Total Losses. resistance widely different from that anticipated by If we revert to the circuit of Fig. 7, and consider the calculation during the working out of the design. total high -frequency resistance that may be introduced It was suspected that, from the point of view of high- into the tuned citcuit by an incautious selection of corn- s Ió

www.americanradiohistory.com DECEMBER 26th, 1928. Ìoillcl F9 High Frequency Resistance. - far as practicable. As a comparison, the following ponents, we arrive at a rather alarming result. Two table gives the minimum additional resistance that can " A " valve -holders, two valves, and an " A " grid - be obtained, on the basis of these measurements, by leak holder provide the following : -_-- using " decapped " valves (two), no valve -holders, and

WAVELENGTH OF TEST. (Metres.) the " B " grid -leak holder. 200 225 250 300 400 550 Wavelength.. 200 225 250 300 400 550 metres Total added resistance 33.5 22.8 16.7 10.9 4.4 2.0 ohms Added resistance.. 2.25 1.7 L3 1.0 0.5 0.2 ohms If these figures are compared with those calculated The difference between this table and the last is so for the coil alone, it will be seen that at the highest wave- overwhelmingly great that it needs no stressing, but as length the resistance is doubled, while at the lowest it pictures speak more clearly than figures, curves of H.F. is increased to nearly seven times the expected value. resistance of coil plus components, on the basis of these Such variations as these, unless allowed for, make re- last two tables, are appended to show the result of a ceiver design a matter of pure guesswork ; it need hardly whole- hearted effort to remove these sources of dielectric be pointed out that it is better to avoid these losses as loss.

SWITCHING OUT AN L.F. STAGE. A Simplified System which Requires no Change of Grid Bias. LTHOUGH there are so many objections to the use portion of the grid -bias battery, through which a small .LA, of switching in wireless receivers that it is, on current, arawn from that battery, must flow. This the whole, a practice to be avoided, yet there are current is so small, being only that which ten or fifteen many who prefer, from motives of economy, to switch volts can drive through the leak, that its effect in dimin- out one valve at least from their receiver when listening ishing the life of the battery need not be taken into to the local station. With certain receivers there is an account. If a five- megohm leak is used-and there is additional advantage in so doing, in that the quality of no necessity to employ a lower resistance than this - reception is often better when fewer stages of amplifica- the current will only be about three microamperes, tion are in use. This is more particularly true when The circuit shown has the additional advantage that in an anode rectifier, which is not easily overloaded, is in listening to the local station, when the value of a distor- use, and in this case especially it pays, from the point tionless amplifier is most clearly felt, the transformer of view of quality, to give the detector a generous input, and amplify but little afterwards, rather than to cut down the input to the detector and to follow it by a consider- able degree of low- frequency amplification. Fig. r shows an anode rectifier coupled by a resistance to the low- frequency amplifier, which is in turn coupled by a transformer to the output valve. This circuit has very wide appeal, and is employed in a large number of receivers now on the market, for it gives the highest amplification attainable with two valves following an anode rectifier, while the quality may be made, by suit- able choice of components and valves, as good as any transformer -coupled amplifier can give. The simple switching arrangement shown in Fig. i enables the low- frequency amplifying valve V2, together with its transformer, to be cut out, by connecting the grid of the output valve V3 to the grid of V2, so that V3 receives directly the output of the detector. The filament Fig. 1.- Switching out the first L.F. valve in an amplifier of the type of V2 may be switched off by means of another pair of used in many popular receivers. contacts on the switch, or by its individual rheostat, if one is fitted. primary is eliminated, so improving the quality. For It will be noticed that the secondary of the transformer distant reception, where high amplification is very help- is still left in circuit, taking the place of the usual grid - ful and small differences in quality are not noticeable leak. By this means grid bias connections need no altera- against the noisier background, the transformer is tion when the intermediate valve is cut out, while the replaced. last valve may still be overloaded, by those who are in the In arranging this circuit in practical form, the switch habit of so doing, without fear of the choking that over- should be placed as close as convenient to the grid of loading brings in its train when a grid condenser and V2, so that the connecting wire may be short, even at leak are used. the expense of lengthening the wire connected to the There is a complete circuit, when the switch is closed, grid of V3. By so doing any ill- effects of the switch through the transformer secondary, the grid leak, and a will be kept to a minimum. B 19

www.americanradiohistory.com 850 WgpASZO DECEMBER 26th, 1928. Wwild

- MOW gangling

ÍIIÌfiIllillüllllMi,;,' CUFN'F 'L:._: TOPIC.J'=' Events of the Week in Brief Review.

PROS AND CONS. AERIAL TOWN. ALL ABOUT TRANSMITTING Controversial topics are to be included The AERIALS. in little town of Colyton, in Devon, German broadcasting, beginning in is Messrs. P. P. Eckersley, T. L. January. becoming entangled in its own wireless Eckersley, aerials. At a recent Council meeting it and H. L. Kirke will give a 0000 joint paper at the meeting of the Wireless BRITISH was decided to ask residents to try to LICENCE JUMP. install Section of the Institution of Electrical An increase of their aerials at the backs of the 34,706 receiving licences houses instead of across the street. Engineers on Wednesday, January 2nd. was registered in November, the total 0000 Their subject will be " The Design of being 2,564,516. The increase noted in Transmitting Aerials for Broadcasting November, 1927, was 18,000. VISITORS TO OLYMPIA. Stations." 0000 During the seven days of the Olympia 0000 AUSTRALIAN WIRELESS SHOW. Radio Show in September, 123,531 visitors OLD SETS PLAY QUEER TRICKS. The Melbourne Exhibition Building is paid for admission. The corresponding " There are too many American homes to be the venue of a Radio Show, organ- number for 1927 was 99,135, and for 1926 with receiving sets bought in 1924 and ised by the Victoria Wholesale Radio 116,570.. The 1926 exhibition was open 1925," declared Mr. O. H. Caldwell, a Association, from April 13th to 20th next. for thirteen days. Federal Radio Commissioner, in a recent 0000 speech. Such homes, he said, were not BOXING DAY VENTURE. listening to 1928 radio. What they were The Calcutta broadcasting station will hearing, without knowing any better, was make a special effort to receive and relay THE COMPLIMENTS 1924 or 1925 radio. the 32 -metre transmission from WGY, 0000 Schenectady, in the early hours Decem- OF THE SEASON MARCONI'S AND FOREIGN of SHAREHOLDERS. ber 26th. TO all readers of The ooo Wireless At an extraordinary general meeting SOUTHEND RADIO SHOW. World, from China to Peru, of the Marconi International Marine Communication Company, The Southend and District Radio we wish a Merry Christmas and Ltd., held on Society will hold its 5th Annual Radio December 14th, it was unanimously Exhibition and Demonstration at a Happy and Prosperous New resolved that alterations be made in the the articles of association providing Boys' High School, Victoria Circus, on Year. May reception grow in that at January 5th. no time should more than 25 per cent. 0000 strength and signals never fade. of the company's issued shares be in the hands of foreigners. MARCONI HOUSE ON THE MARKET. 0000 Marconi House is now in the lists of THE TELEVISION SOCIETY. WIRELESS PICTURES AS SOUVENIRS. the estate agents preparatory to its sale when the wireless -cable Mr. J. Cameron Rennie, B.Sc., A sum of £1 10s. 6d. was realised by merger company the sale of wireless enters into occupation of new premises M.I.E.E., will lecture on " Scanning pictures at a recent on the Embankment. Methods Used in Television " at a meet- luncheon of the Glasgow Business Club, 0000 ing of the Television Society on January the money being handed over to a fund WHERE THE " SPARKS " GO. 1st, at 8 p.m:, at the Engineers' Club, for disabled ex- Service men. Three of At the recent annual Coventry Street, London, W.1. the pictures were received from Daventry dinner at Ports- on a " Fultograph mouth of past and present 0000 " during the luncheon ; members of the others had been received the Royal Naval Wireless Society it A SEDUCTIVE OFFER. on different was occasions from Berlin and Vienna. stated that many " ex- sparks " were now A Southport firm of building contrac- 0000 engineers of the B.B.C.0000 tors announces that, all purchasers of a NEWS PICTURES AT SEA. house or bungalow to the price of £495 BERLIN RELAYS Following the recent production of the JAVA. will be given a wireless receiver, com- first picture paper printed On December 14th ever and pub- the Berlin broad - plete with loud speaker and all acces- lished at sea, the Daily Tclegraplt pic- castiilg stations successfully relayed a sories, installed free of charge. ture Wagner concert from broadsheet was a daily feature on Java, in the Dutch 0000 board the Olympic on her voyage to East Indies. The transmitter was BEAM BRINGS PROSPERITY TO New York last week. Bandoeng, on 31.93 0000metres. AUSTRALIAN WIRELESS. The pictures, transmitted from Rugby, The Amalgamated Wireless Company MAN -MADE STATIC. and received on an ordinary " Fulto- of Australia has just paid its first divi- graph " instrument, consisted of typical The Austrian Parliament is shortly to dend since 1922. The new dividend is news photographs. consider a Bill Although the making it a punishable 6 per cent. for the year ended June 30th Olympic encountered heavy weather, offence to operate high -frequency appara- last. It is understood that the increased tus for massage this in no way affected reception, though or other purposes to the profits are due to the company's beam it caused some difficulty in the making detriment of broadcast reception. system. of process blocks.

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www.americanradiohistory.com DECEMBER 26th, 1928. WAwasms, 85z Woad TELEPHONING TO TRAWLERS him on the telephone and knowing that Finder Type 11G is the latest design of A wireless telephone operator has been his friend was listening to a message marine direction finder, and uses high - specially detailed at Humber Radii, to from the Byrd Antarctic Expedition frequency amplifying valves of the facilitate communication between trawlers 10,000 miles away, he got in touch with screened -grid type. on the Dogger Bank and the owners and the operator in the expedition ship, Another feature of this instrument is relatives on shore. Many of the trawlers Eleanor Bolling, who in turn relayed the introduction of two calibrated dials are now fitted with telephony sets, the message to the sealing vessel City of in the direction finder unit. One is though not equipped with ordinary ships' New York. The operator on this boat fixed, and the bearings indicated thereon wireless installations. included thd message in a Press dispatch are relative to the ship's head. The second oó00 to New York, and it reached its destina- dial is rotatable, and on being set to the THE PHANTOM ORCHESTRA. tion only a few miles from its starting ship's true course will indicate true bear- point. ings that need no providing The latest combined gramophone and 0000 correction, wireless reproducer is known as the the ship is on her course when the bear- name INTERNATIONAL WIRELESS ing is taken. " Phantestra." A company of that OPERATORS' MEMORIAL. has been formed with a capital of 0000 of £250,000. It is stated that the " Phan - The parents Michael Joseph PHYSICAL AND OPTICAL SOCIETIES' testra " will be supplied either in the O'Loughlin, the wireless operator who EXHIBITION. form of a super model for cinemas, lost his life in the Vestris disaster, have been informed by the Veteran Wire- The Nineteenth Annual Exhibition of theatres, etc., or as a cabinet model for the Physical and Optical Societies is to home use. less Operators' Association that their 0000 son's name is to be inscribed in granite be held on Tuesday, Wednesday and on the wireless operators' monument in Thursday, January 8th, 9th and 10th, LUXURY OR NECESSITY? Battery Park, New York. The monu- 1929, at the Imperial College of Science, A Peckham resident, summoned for ment was erected in 1915 and is inter- Imperial Institute Road, South Kensing- working a wireless set without a licence, national. It carries the names of opera- ton, and will be open in the afternoon pleaded that he was on short -time work, tors of all countries who have died in the from 3 p.m. to 6 p.m., and in the even- but had intended to take out a licence course of duty. ing from 7 p.m. to 10 p.m. when his work was full time. Over eighty firms have accepted the The Magistrate : Wireless is a luxury. invitation to exhibit in the Trade Section If you can't afford, you should not install FORTHCOMING EVENTS. at this exhibition, and in addition a it. WEDNESDAY, DECEMBER 26th. group of research and experimental ex- The defendant was fined half -a -crown Edinburgh and District Radio Society. - hibits is being arranged, which will be and 10s. 6d. costs. At 8 pan. At 217, George Street. Lec- shown by Fellows of the Societies and 0000 ture by Mr. M. Scroggie, others, and a number of research labora- TRANSATLANTIC GREETINGS BY THURSDAY, DECEMBER 27th. tories and other institutions. Some in- 'PHONE. Slade Radio (Birmingham). -At 8 p.ne. At the Parochial Hall. Members' Night. teresting historical exhibits will also be The Postmaster- General announces Talk on Electricity. included. that for members of the public who wish Golders Green and Hendon Radio Society. -Third dance. At 7.30 pm At the On January 8th Professor F. Lloyd to exchange greetings with friends in Cl ub House., Wülifield Way. Fancy Hopwood, M.A., F.Inst.P., will deliver dress optional. (Tickets 6d., inclusive Canada, the United States, Cuba, or 3s. a lecture on " Experiments with High - Mexico arrangements have been made of ref rechne enta.) MONDAY, DECEMBER 31st. frequency Sound Waves." to open the Transatlantic telephone ser- Invitations to the exhibition have been tam. Hackney Radio and Physical Society. -At vice at 8 (British time) on 8 pan. At the Electricity Showrooms, sent to the Institution of Electrical En- Christmas Day instead of at the normal Lourer Clayton Road, E.5. Informat gineers, the Institution of Mechanical meeting: Discussion of Future Pro. hour of 1L30 a.m. The service will gramme. Engineers, the Royal Aeronautical remain open all day and up to 3 a.m. Society, the Royal Meteorological Society, on December 26th. Society, and a number of ILLICIT TRANSMISSIONS IN the Faraday 0000 SOUTH LANCASHIRE. other societies and bodies. As in previous EMPIRADIO AT CHRISTMAS. these societies should by Office engineers years, members of Special arrangements been A year's search Post to secretaries. have made in the appearance at the apply for tickets their by the Post Office to enable the public to culminated on application Court last week of Cecil Others may obtain tickets make the utmost use of the Imperial Bolton -Police to the Secretary, the Physical and Opti- wireless and cable services for the dis- Grundy, of Rishton Lane, Bolton, who Ex- guilty of operating a wireless cal Societies, 1, Lowther Gardens, patch of Christmas New Year greet- was found Tickets and without a licence. He was hibition Road, London, S.W.7. ings. A similar service will be intro- transmitter required only on January 8th and 9th. fined £5 and ordered to pay £5 5s. costs. are duced for the first time to most Euro- Admission on the third day, Mr. Frank Elliott, prosecuting for the January pean countries. 10th, will be without ticket. for Ceylon Post Office, said that Grundy's call sign Messages India, Burma and in for via Empiradio are accepted at 2s. 6d. ORS had been heard Manchester 0000 two years, usually on Sundays and at mid- for ten words and 3d. per word there- had WIRELESS AT WESTMINSTER. after. The same rate holds good for night, after ordinary -broadcasting via or ceased. Engineers had made about twenty (From Our Parliamentary Correspondent.) messages to Canada Imperial Em- down piradio. Reduced rates are also in force visits to the town before narrowing The New Broadcasting Premises. for greetings to South Africa, Australia the search sufficiently to detect the de- fendant's set. He added that there were Mr. Malone asked tho Postmaster - and Kenya. General last week whether the British All greetings telegrams by these ser- more unauthorised transmitting stations in South Lancashire than in all the rest of Broadcasting Corporation obtained his vices should bear the indication " XLT," approval before deciding on the purchase which is charged as one word. The England put together. 0000 of new premises ; and, if so, whether the reduced rates remain in force until question of a national opera house was January 2nd. 000 SCREENED -GRID VALVES IN D.F. considered. Messrs. Elder Dempster & Co., Ltd., Sir W. Mitchell -Thomson said that this A ROVING MESSAGE. bave given orders for their ships Adda, matter was dealt with by the British Probably the most roundabout method Accra, Apapa, Appa7n and Abtnst to be Broadcasting Corporation under the of sending a wireless message was that fitted with Marconi direction- finding ap- general powers which had been conferred adopted recently by the radio operator paratus, and the work of installation will upon them, and it was not necessary for in the New York Times office who proceed as the ships become available. them to obtain his approval. The second wished to communicate with a friend in The Marconi International Marine part of the question did not therefore a New York suburb. Unable to reach Communication Company's Direction arias B 2I

www.americanradiohistory.com 852 WIpagoo DECEMBER 26th, 1928. Would

Vv

A Review of Manufacturers' Recent Products.

"TAYLORADIO" H.F. CHOKE. curve which is not too peaked, and was good, and it is only when the very The winding of this choke is air spaced, gives the following values :- lowest frequencies of the order of 30 or and is wound in seven sections supported . Wavelength Impedance 50 cycles are reached that any inferiority on slotted vertical ebonite rods. The (metres). (ohms). to more expensive transformers is noticed, 200 12,800 and then only to a small degree. 500 47,700 The transformer has a ratio of 4 : 1, 1,600 ...... 263,000 and the inductance of the primary was shown Resonance occurs at about 2,200 metres, by measurement to be 12.2 henrys up to which wavelength the choke without D.C. flowing through the wind- can be ings. used without fear of self oscillation. The " Tayloradio " choke is make by Messrs. W. W. Taylor, 33, Furnival Street, London, E.C.4, and the price is 4s. 6d. u C 0 0 MARCONIPHONE " POPULAR " TRANSFORMER. The small dimensions of this trans - former -4in. x2-'ain. x1 in.-make it emi- nently suitable for use in portable sets Tayloradio" ILF. choke; D.C. resist- or where space is limited. In spite of ance, 770 ohms. its small dimensions, it has a remarkably good performance when preceded by a windings are set up in a cylindrical glass valve of medium impedance, e.g., 10,000 tube mounted on an ebonite base provided ohms. A practical test proved the repro- with terminals. duction to be clean and crisp; the ampli- The choke has an excellent impedance fication of extremely high frequencies

Marconiphone " Popular " L.F. trans- former for use in portable sets. TAYLORADIO H F. CHOKE The screening case is fitted with rever- sible feet and the transformer can be mounted with the terminals in the best 300,000 position for wiring A twelve months' guarantee is given and price 12s. x the is 6d. 0000 200,000 z GAMBRELL VOLUVERNIA. This is a high resistance potentiometer W designed primarily for use as a volume control. The maximum resistance of the 100,000 particular specimen tested was within 2 per cent. of its stated value and the minimum resistance, with the moving contact just free from the end stops, ap- proximately 300 ohms. Between these two limits value is o the change practically 50n 1.000 1.500 2,000 2,500 3,000 3,500 proportional to the angular displacement WAVELENGTH (METRES) of the control knob. Only at one part of the track was there any appreciable de- viation from the straight line, and this Impedance curve of the "Tayloradio" H.F. choke; external capacity, 8 micro -mids. was in the order of 8 per cent. only at B 22

www.americanradiohistory.com DECEMBER 26th, x928. Wflpd@tg g53 WayIl4 the maximum. The movement is very The old D.E.3 valve used in conjunc- meats. The receiver would continue to smooth, denoting an even pressure at all tion with dry batteries of the bell -ring- give signals with less than the normal parts of the track, and this doubtlessly ing type, partly solved a problem which filament current, probably for a further attributes largely to the steady change in now finds its complete solution in the use 50 or 100 hours, depending on the type resistance over the whole scale. The re- of large capacity wet Leclanché cells. of valves used. The life of the battery sistance changes from maximum value to These cells are well suited for supplying can therefore ba put at about 450 work- minimum in slightly less than one com- filament current to modern " point one " ing hours, which is equivalent to six plete revolution of the knob. The com- filament valves and should run a two - months.' normal use. It is interesting ponent is intended for panel mounting, valve set for 6 months on more without to note that this will also be the aver -. and is provided with a single hole fixing attention. age life of the H.T. battery if its capa- attachment. The makers have apparently The " Standard " sac Leclanché low - city is correctly chosen to suit the anode tension battery consists of two cells en- closed in a wooden cabinet measuring 124in. x 64in. x loin. The cells are separated by a partition and the glazed earthenware jars are treated at the top, with paraffin wax to prevent creeping of the electrolyte. The saes and zincs are of unusually largo dimensions, and completely fill the interior of the jars, the inside dimensions of which are 71in. x 4,1in. diameter. The zinc is separated from the sac by square- se.:tion .rubber rings. The maximum economical discharge of the battery is 0.25 amp., which is the current required by the average 2 -volt two -valve set employing a 0.1 filament detector and a 0.15 filament output valve. In order to keep the current constant during the life test, a variable resistance was employed in conjunction with a fixed minimum re- sistance of 8 ohms. The fixed "Standard" sac Leclanché low tension Gambrel! " Voluvernia," a one- megohm resist- battery. potentiometer primarily intended as a ance represents the two -valve filaments volume control. in parallel, and the variable resistance current taken by the set and the re- given careful thought to the design, and, is necessary in order to keep the volt- plenishment of both batteries may be age across the filaments 2 same time. bearing in mind the extensive use of metal constant at undertaken at the panels, have supplied with each component volts. The initial voltage of the bat- When renewing the L.T. battery, two ebonite bushes. In these cases a tery is 3.0 volts (1.5 volt per cell), so fresh sacs as well as zincs should be half -inch diameter hole must be drilled that a variable filament resistance of used, and the cost of recharging, in- in the panel, but for mounting on insulat- not less than 4 ohms is essential in any cluding electrolyte, will amount to 14s. ing material the ebonite bushes can be receiver using these batteries for L.T. A thin layer of oil on the surface of removed and a gin. hole will suffice to supply. If the resistance is not in- the electrolyte is recommended and will clear the fixing attachment. corporated in the set it must be fitted prevent evaporation. Oil was used in The component is particularly suited externally- preferably in the -FL.T. lead. the battery under test, and no addition for use in any position provided it is not Throughout the test the resistance was of water was necessary during the timo required to pass too large a current. adjusted to keep the current constant at of the test, the liquid maintaining the For example, it can be connected across 0.25 amp., and this value was main- correct level throughout. the input terminals of a gramophone am- tained for the first 400 hours. By this The battery is made by the Standard plifier and the moving contact taken to time the contact arm on the resistance Wet Battery Co., 184 -188, Shaftesbury the grid of the valve with one end of the had reached zero, and from 400 hours Avenue, London, W.C.2, and the initial resistance element connected to a suitable onwards the only resistance in circuit cost complete with electrolyte is point on the grid bias battery, or it can was the 8 ohms representing the fila- 26s. 6d. be used in place of the grid leak in either a resistance- capacity or choke -coupled 05 amplifier. Many other uses will suggest STANDARD LECLANCHE II::ICIIIIII=IIIIQI=I::IIIIII.I1 themselves to the experimenter. The L.T. BATTERY component is very compact, the dimen- CC::CC :::' sions being tin. in diameter over the ter- C=iC:C==llEEB:::=:Z'I=..i minals and lin. in depth. The makers cmIl°a ....::::::::::: ::.r. are the Gambrell Radio, Ltd., Bucking- mom ham House, Buckingham Street, London, : aa. Ómo mom W.C.2, and the price is 6s. 9d. m...... 0 0 0 0 : " STANDARD " LECLANCHÉ : .....:..::...... :::::::::::::5:::::::::::::_::...... \a L.T. BATTERY...... It is in remote country districts that :C:::I::::::I:::::::I:::=::I:C:iii=iiiiï:;;I::':7 the benefits of broadcasting are most ... appreciated, yet it is in these circum- IMEMMrM ....u...ME m..mo stances that there is difficulty in installing o :::I ...... gm=s:=iIiliéáïe=EciiiI=E:E:::::_ a valve set owing to the problem of accu- 100 200 300 400 500 mulator charging. i\lany isolated farmers at present struggling along with TIME WORKING HOURS) a crystal set and a big aerial would willingly purchase a valve set if they be Discharge curve of the "Standard" L.T. battery; current maintained constant at could assured of trouble -free service 0.25 amp. by means of variable resistance until E.M.F. tell below 2.0 volts whet. over a reasonable period. the resistance in circuit was maintained constant at 8 ohms. B 23

www.americanradiohistory.com 444(4-.1k.

851 `Iñpig,M0 DECEMBER 26th, 1Q28. WOlfIld

A Stable Set Covering all the Short Wavelengths. v, By H. F. SMITH. F4 HORT -WAVE broadcasting has come to stay. Un- Sender " -are projected or actually in course of con- less something amounting almost to a new prin- struction. A short-wave set is now a useful addition to ciple in transmission is evolved, this statement may the equipment of a wireless amateur in this country, as be made with confidence, in view of the fact that many it opens up a new field for his interest and amusement, existing stations are increasing their activities, and new but to the exile abroad it is a great deal more than this. ones -among them the high -power German " World In many cases short waves afford the only really prac- ticable means of reception, and in others they bring H.T. t from Home -in spite of out present rather rudimentary service much appreciated 11--- TO L.T.- -a 05 supplement to local pro- grammes which are often inadequate. The set to be described in this article is intended to meet the needs H.F.C. a0 of users both at home and 03 abroad, but particular atten- tion has been given to the 02 requirements of the latter. H.T.- Those without experience °- of the short waves must not imagine that they afford a aó c, royal road to consistent re- yq O ception of distant stations. They do not ; for some L.T. reason not yet fully ex- + plained, signals which are normally good will at times .B.1. -G.8.2 +G B. almost disappear for many days on end. Fortunately, this disability has its com- 1. -The circuit diagram. Cl, 0.00015 C2, C3, 0.0001 mid.; mid.; C4, 0.00025 mid.; C;;, . pensations ; for long periods C7, Cs, 2 :olds.; C6, 0.01 mid.; 111, 5 megohms; R2, 20,000 ohms; R7, 20,000 or 50,000 ohms ; R4, 250,000 ohms; R7, 1 megohm; R3, 100,000 ohms. excellent reception is pos- B 24

www.americanradiohistory.com DECEMBER 26th, 1928. Wh'shoo 55 , Would:

Special Precautions are taken to Counteract Hand. =capacity Effects. sible with the simplest apparatus. It is true to say that The circuit diagram, Fig. i, shows that the first valve when signals are coming in really well, they can be operates as a grid detector, and is coupled to the L.E. received on almost any skilfully handled set, even if it amplifier by a resistance of low value, in series with has serious shortcomings ; during the " fading " periods which is a decoupling resistance with its by -pass con- nothing will yield satisfactory results. It is when denser. The next stage is transformer coupled. A signals are of medium intensity that one most appre- choke output is so arranged that one side of the 'phones ciates a receiver with some reserve of amplification, free- or Ioud speaker is earthed, while a suitable jack affords dom from hand -capacity effects, and with controls that a convenient method of connecting either of these instru- are not too difficult to operate ; there is little pleasure in ments at will, and also switches on the filament current. working with a tricky and unstable set. The set is completely screened, so In designing the present set, the hand -capacity effects are negligible writer has been helped by correspon- provided the earth connection is of dence from readers in many parts of reasonably low resistance. the world with regard to the original " Empire " receiver, described in The Metal-sheathed Container. The Wireless World of June 29th, Screening is effected by enclosing 1927 ; some of the modifications in- the apparatus in a metal cabinet ; in cluded are the result of these sugges- this matter the constructor may follow tions. An extra L.F. stage has been his own ideas, but will be wise at least added to give adequate magnification to retain the metal front panel if he for loud speaker reproduction when prefers to use a wooden box. The signals are really good enough, but container illustrated is made of " Ply - this stage is so arranged that amplifi- max," a material consisting of ply- cation is not excessive for reception wood covered each side with thin with 'phones. Regeneration control sheet metal, the total thickness being has been improved by adopting the ¡in. It was built by the manufac- " parallel feed " throttle method, turers to the writer's specification. with close magnetic coupling between The construction is shown in Fig. 2. grid and reaction windings. Instead The front panel is sheathed with of a single tapped tuning coil, plug -in copper, which, before assembly of the inductances of simple construction are components, was given an " engine - used ; it is thus possible to use the set turned " finish by rotating a piece of for reception on the normal broadcast fine emery paper at regular intervals Plug-in coil for tie 23-48 metre wave- waveband if desired. bawl. over the surface, which was then pro- 8 25

www.americanradiohistory.com 856 WAnhoo DECEMBER 261h, 1928. WavIld The New 3mpire Receiver. - Most of the important short-wave broadcasting stations tected by a, coat of clear cellulose lacquer. The re- operate between 23 and 45 metres, so one of the coils mainder of the box is sheathed in lead -coated steel. -the most useful of the series -is arranged to cover In addition to the holes indicated in Fig. 3, the posi- this band. Its grid winding has 6 turns, with a tions of which are given in relation to the inside dimen- reaction section of 3 turns. sions of the container, the front panel must be drilled for the securing screws of the variable condenser and its dial in accordance with the template supplied by the manufacturers. Three tin. holes are also drilled through the back ; two of them immediately opposite the apertures of the terminal block (for aerial and earth leads) and a third to pass the battery leads. Before discussing con- struction of the set proper, it BACK OF CASE DRILLED will be as well to describe To TAKE AERIAL EARTH the coils, which are the only AND BATTERY LEADS " home -made " components 71 Fig. 3.- Dimensions of the screening box. Inside measurements used. They are wound on are given. AERIAL COIL REVERSE SENSE TO REACTION COIL 3in. lengths of " Becol " six -ribbed ebonite former, For =%/ryl/Gír"//=f the ultra -short waves, from i6 metres upwards, a 22in. in diameter, fitted with coil with a total of three turns in both the grid and re- i ri ii ii four pins spaced as shown action sections is suitable. The maximum wavelength in the practical wiring plan. attainable with this inductance is 28 metres, so there is Actual dimensions are not ample overlap. In both cases, adjacent turns are given, it is Fig. 2. - Construction of as best for the spaced kin. between centres. coils and base. constructor to drill his own formers, using the first as a Up to 90 Metres. guide in marking off the others, and also the base ; by With the exception of KDKA, there are not many these means it is easy to ensure that all the coils will fit high -power short -wave transmissions above 45 metres, properly. but to complete the series another inductance may be The disposition of the windings is shown in Fig. 2, wound with 4 reaction turns and a grid coil of 121. turns, from which it will be seen that the reaction winding is with a spacing of in. This covers a wavelength of under the low- potential end of the aerial -grid coil, and from 38 to go metres. The ends of the windings are is parallel to it, being wound at the bottom of slots cut in the ribs with a fine saw. These slots must be suffi- ciently wide to take the fine wire reaction winding (No. 36 D.S.C.), but the thicker wire (No. zo tinned copper) of the grid coil rests in shallow V- shaped depres- sions filed in the lip of the slots, which should be of such a depth that the spac- ing between the two wires is -gin. It is essential that these two coils should be wound in opposite directions, and to simplify matters the series of slots are cut so that the windings are not in the form of a regular helix, but advance from turn to turn 214-4-s-I1/;.-s--1% .. at a fixed point between two ' adjacent ribs. Both wind- ings should make their ad- Fig. 4.- Position of components on the baseboard. Nate sponge rubber support of detector vance at the same point. valve holder. B 26

www.americanradiohistory.com WapigIl®0g DECEMBER 26th, 1928. opíld 857 The New Empire Receiver.- final connections to the terminals of its holder must be jointed to their appropriate pins in accordance with made with short lengths of flexible wire ; otherwise the Fig. 2, care being taken to make each connection to a advantage of a shock -absorbing mounting will be lost. pin which will engage with a socket on the base bearing Tinned copper wire, No. 20 gauge, was used for corresponding lettering (Fig. 5). The base itself con- wiring up the receiver illustrated. Battery leads of sists of two 2lin. discs of /in. ebonite, the upper of flexible wire are joined to appropriate points ; it should which carries four short sockets, the lower merely serv- be noted that the positive L.T. lead is taken direct to ing to insulate their projecting ends. The whole the upper contact of the jack. All these wires are assembly is secured to the baseboard by three screws. plaited or twisted together and.passed up through a hole near the rear edge of the baseboard. Points in Mounting and Wiring. The two variable condensers and jack should now be Care has been taken to reduce the overall dimensions mounted on the panel, after which the baseboard may of the set to a practical minimum, but in the course of be fitted and the few remaining leads joined up. It will assembly and wiring no difficulty will be experienced if be observed that a connection is made to the cabinet

Rear view of receiver with lid fully opened. The decoupling resistance is removed from I:s hold r.

the right course of procedure is followed. The first step metalwork via the tuning condenser frame from the is to prepare the wooden baseboard, which measures common L.T. and H.T. negative lead ; it therefore fol- 14in. by 8in. by tin. in thickness, and is fitted with a lows that the body of the jack and one set of vanes of batten tin. wide and lin. thick at each end in order to reaction control condenser C4 will be in metallic connec- provide space for wiring. Components should now be tion with the same point ; if a panel of insulating material mounted on it in positions indicated in Fig. 4, after is used, extra leads must be added. which the majority of connections may be made before fitting it in the cabinet. Details of Assembly. Valve filaments are wired with bare leads, passed The Sterling L.F. choke is fitted with feet, of which through the baseboard and insulated only by the wood, the position may be altered so that the component may which is quite adequate for these low-tension circuits. be mounted in any desired manner : one of these is It will be noticed that the detector valve is mounted on secured to the baseboard, and the other, by means of a a block of sponge rubber- microphonic noises are par- screw, to a 4 B.A. nut soldered to the rear surface of ticularly objectionable in a short -wave receiver -so the the panel. This is quite a simple operation, but it is B 27

www.americanradiohistory.com 858 WilTtshoo DECEMBER 26th, 1928. Woltca The New Empire Receiver.-

LIST OF PARTS. 1 Variable condenser, 0.00015 mfd. (Cyldon)r i L.F. choke, 30 henrys (Sterling). .1 Reaction condenser, 0.00025 mfd. (Polar). i Anode resistance, 20,000 ohms, with base (Igranic). 3 Condensers, 2 mfds. (.Sterling) i Anode resistance, 50,000 ohms, with base (Igranic). 1 Condenser, 0.0001 mfd. (Dnbilier, Type 620). 1 Terminal block (Athol Electrical Co., Tyson Street, Cheethom Hill, i Condenser, 0.01 mfd. mica (Dubitier, Type B. 776). Manchester). 1 Condenser, fixed, air dielectric, 0.00d1 (Ormond). 3 Valve holders, skeleton type (Pye). 1 Slow- motion dial (Bowyer -Lowe). 1 Potentiometer, porcelain (Igranic). 1 R.F. Choke (Igranic, short -wane type). i Jack, single circuit open, filament control (Edison Bell, Type 11/166). 1 Resistance, 250,000 ohms (Ediswan) i Plug (Edison hell, Type R1168). 1 Resistance, 100,0'10 ohms (Ediswan). fr 3 Ribbed formers, 54m. dia., 3in. long (Becol). 1 Grid leak, 5 megohms ( Ediswan). 1 Cabinet, metal -sheathed plywood (Venesta, Ltd., Vintry House, Queen i Grid leak, 1 meyohm ( Ediswan). Street Place, London, E.C.4). 4 Grid leak holders, porcelain (Bulgin). Wire, .screws, ebonite, etc. 1 L.F. transformer (Ferranti, A.F.4). Approximate cost, including cabinet, but without valves and accessories, £7 28. 6d. In the "List of Parts " included in the descriptions of THE WIRELESS WORLD receivers are detailed the components actually used by the designer, and illustrated in the photographs of the instrument. Where the designer considers it necessary that particular components should be used in preference to others. these components are mentioned in the article itself. In all other uses the constructor can use his discretion as to the choice of components, provided they are of equal quality to those listed and that he takes into consideration in the dimensions and layout of the set any variations in the size of alternative components he may use.

Fig. 5.- Practical wiring plan. The frames of both variable condensers and of the Jack are in metallic connection with the screen and the common negative lead. Leads which pass through the baseboard are shown in dotted lines. The single connection to G* must be made to the insulated set of vanes. necessary to mark the exact position of the nut before For the detector position, a good " general purpose " the baseboard assembly is finally placed in position. valve, with amplification factor in the order of 20, is It may be added that this method of fitting is adopted a safe choice. As a first -stage L.F. amplifier, a similar only to avoid defacing the front surface of the panel by type will do excellently, but where headphone reception a screw head, and that a second support is unnecessary only is required, an " L.F." pattern giving a smaller unless the set is likely to receive rough treatment. overall magnification is perhaps more pleasant to work B 28

www.americanradiohistory.com DECEMBER 26th, 1928. WApishsoo 859 WOrIld The New Empire Receiver. - in Fig. 5) so that contact may be made at any point with- with. Choice of an output valve is, as usual, governed out introducing a short -circuit between turns. As a entirely by requirements as to volume, and need not be start, it should be joined to include a single turn ; if discussed here. oscillation cannot readily be produced with this con- nection, it should be moved half a turn nearer the Aerial Coupling Adjustments. earthed end. If, on the other hand, there is a tendency It will have been noticed that one of the coil base towards too free oscillation, it will be as well to reduce sockets is " idle," and (from the practical wiring plan) the capacity of the feed condenser as already described. that the aerial lead -in terminates in a short wander lead Smoothness of reaction control is even more important, carrying a spring clip. This is for the reason that it is in a short -wave set than the highest possible detection often necessary to vary the position of the aerial tapping efficiency, so the grid potentiometer should be set at a on the grid coil, and it is convenient to have a ready point which gives the best practical compromise ; gener- means of making connection at the point found to be ally speaking, this condition will be realised if its slider best by trial Generally speaking, this tapping will vary is rather nearer the negative than the positive end of from a point half a turn to three turns above the lower its winding. (earthed) end of the coil, the first -mentioned position Finally, the question of reception of normal broad- being suitable for the shorter wavelengths. The fourth casting stations. In view of the necessarily low capacity pin is retained, however, both to give rigidity to the mounting and to serve as an aerial connection for the broadcast coil, which is to be described later. In the inscription under Fig. 1, the value of the de- coupling resistance R3 is given as 20,000 or 50,000 ohms. This point requires a word of explanation : it will be realised that the resistor, apart from its function of deflecting signal currents from the common battery circuit, also reduces the voltage applied to the detec- tor anode. The first -men- tioned value is suitable for applied voltages of less than loo, and the second for pressures above this and up to some 14o volts, which is the maximum likely to be used. Throttle reaction of the type included depends for its operation on the relation- ship between the values of the feed (CO and control Plan view of the receiver. (CO condensers, and it is for the reason that some adjustment may be necessary to of the tuning condenser, the band covered is strictly the capacity of the first mentioned that a component limited, but by winding a coil with a grid section of with an air dielectric is used ; this may easily be reduced 95 turns of No. 28 D.S.C., wavelengths from about 300 by removing one or more of the plates. to 50o metres may be received. The associated reaction It is recommended that the 23-45 -metre coil should coil has 14 turns of No. 36 D.S.C. divided between two be used for initial tests. Among the transmissions on narrow slots spaced tin. apart, under the earthed end this band are those of the well -known Schenectady relay of the grid section. An aerial tapping is made at the station, 2XAF, Pittsburgh on 27 metres (which at the loth turn, and is joined to the pin which, in the short- time of writing is " coming over " better than any wave inductances, is idle. Its corresponding socket other American station), Chelmsford, Melbourne, and carries a tag projecting beyond the edge of the base, to PCJJ. At the top of the tuning scale will be found which the aerial clip may be attached. the amateur telephony transmitters on about 42 metres. This set is available for inspection by readers at the The jaws of the crocodile clip used for connecting offices of "The Wireless World," 116 -117, Fleet Street. the aerial to the grid coil must be filed away (as shown London, E.C.4. B 29

www.americanradiohistory.com 86o WAp®Il®gg Walc DECEMBER 261h, 1928. A`BRO

1 11I1 1 1!Illl1l0 lf ,11I SRJ,

BARCELONA (Radio Barcelona), Call EAJ7 (344.8 Variety ; 8 30, Programme in Frankfurt Dialect, fol- metres) 1.5 kW. Selections : - -8.10, Sextet Two lowed by Dane Music from Voahaus, 11.30 ( approx.), Step, Clásico (Marti) ; Selection from La casita Close Down. blanca (Serrano-Pacheco) ; Intermezzo, Capricho andaluz (Orejón) ; Waltz, Dolores (Waldteufel) ; HAMBURG 1! HA (in Morse) (304.7 metres) ; Selection from Manen (Massenet). 8.30, Elementary 4 kW, 3.á, lustrated Music Talk, by Dr. Will. French Lesson. 9.0, Chimes and Weather Report. Heintz. 3.30 Mass in C Major (Schubert) for Four 9.5, Exchange Quotations and News. 9.10, Orchestral Voices, Orches ra and Organ. 430, Request Pro- gramme. Prufer, : Concert : Two -step, Como los buenos (Jarque) ; 6.30 Dr. Johs. Talk School Punish- Selection from La Gran Via (Chueca and Valverde - ments--a Que ion of Practical Discipline. 6,0, Dr. Meusch, Finck) ; Waltz, Estudiantina (Waldteufel) ; Fox -Trot, Talk Handicraft, relayed from Hanover My inspiration is you (Leslie, Nicholls -Somers) ; (297 metres). 6.25, Herr B. Rösoler, Talk : The Build- Pizzicato, The Twilight Serenaders (Hoby) ; Czardas, ing of a Market Hall to Hamburg. 6,55, Weather Bonka (Michiels). 10.0, Programme relayed from Report. 7.0, Concert of Popular Music : Three Madrid, EAJ7. SATURDAY, DECEMBER 29th. Selections from The Barber of Seville (Rossini) ; Mücke und Frosch (Sommerstorff) ; Uebertrumpft BERGEN (370.4 metres) ; 1.5 kW,-- -5.30, Programme (Sommerstorff) Air from Der Freischütz (Weber); for Girls. Programme 6.0, for Children. 7.0, Orches- All Times are reduced to Greenwich Overture to The Czar and Carpenter (Lortzing); tral Concert. 7.20, Selections by the Wiener Schram- Duet from Undine (Lortzing) ; Song from The Czar mel Quartet. 7.50, Topical Talk. 8.0, Talk by Colonel Mean Time and are p.m. and Carpenter (Lortzing) ; Die Fliege im Zirkus J. Wahl. 8.80, Sonata in G Major for Pianoforte and except (Hochstetter) ; Overture to The Merry Wives of Violin (Grieg). Weather Report, and Time 9.0, News where otherwise stated. Windsor (Nicolai) ; Songs from The Merry Wives of Signal. 9.15, Dance Music. 11.0 (approx.), Close Windsor (Nicolai) ; Feldpredigers Kriegstaten(Körner); Down. Overture and Air from 1 he Barber of Bagdad (Cornelius) BERLIN (Köuigswusterhausen) (1,649 metres) ; 40 Air and Waltz from Der Rosenkavalier kW. -3.80, Programme from Hamburg. Dr. (Stolz) ; March, Fideler Bauer (Fall) ; Waltzes from (Strauss). 9.80, Weather Report, News, Sports Notes 4.30, Liebe im Schnee (Benatzky). and Programme Announcements, Gustav Manz, Talk : Public Speaking. 5.0, Industrial 9.0, News. 9.30, followed by Concert Talk. 5.30, Elementary Spanish Lesson. Dr. Dance Music. from the Café Wallhof. 10.50, North Sea and Baltic 5.56, Weather Report. M. H. Böhm, Talk : The Problem of the Eastern BR$NN (441.2 metres) ; 2.5 kW.- -4.45, German Frontier States. 6.20, Prof. Ehrenbaum, Talk: The Programme. 5.16, Wireless Review. 6.0, Orchestral HILVERSUM (1,071 metres) ; 5 kW.-9.40 Herring Industry. : 7.0, " Agricultural " Programme Selections. 6.45, Dr. Stanek, Talk : Czech Literature Time Signal and Daily Service. 11.40 a.m.. Police Hunter's Chorus from Der Freischütz (Weber) ; Abs- from the National Reformation until To -day. 7.0. Announcements. 11.55 a.m., Concert of Trio Music. chied vom Walde (Mendelssohn) ; Selection for Bugle Programme from Prague. 8.0 Concert of Popular 1.40, Musical Programme, relayed from the Tuschiuksi Quartet ; Baritone Solos, (a) Selection from Das Music : Overture, In the Well (Blodek); Czech Picture House, Nachtlager Amsterdam. 8.40, Italian Lesson by von Granada (Kreutzer), (b) Jagdlied Suite (Moor) ; Songs (Steinmann) ; Czech Dances Giovanni Rizzint. 4.40, French Lesson by M. (Mendelssohn Raymond -Bartholdy) ; Jagdfanfare for Bugle (Smetana) ; Songs (Novotny) ; The Blacksmith of Lafont. 5.40. Time Signal. 5.41 Concert of Trio Quartet (Lindner) ; Humorous Hunting Stories; Lesetin (Suds) ; Slavonic Dances (Dvorak), 9.0, Music. 8.23, German Lesson by Herr Edgar Grün. Selection for Bugle Quartet, Die lustigen Jagabuan Programme from Prague. 9.25, Dance Music relayed 725, Police Announcements. 7,40, Programme, (Koschat) ; Baritone Solos, (a) mein Willkommen Wald from Bratislava (300 metres). arranged by the Workers' Radio Society : Talk and (Kranz), (b) Das Jägerhorn (Pohlens) ; O Wald, wie Concert. 11.15 (approx.), Close Down. BRUSSELS metres) ; 1.5 kW, Orchestral ewig ; (508.5 -5,0, schön bist du (Reinecke) Bugle Quartet Selec- Concert tion, Jägermarsch (Lorenz). 8.0, Talk on Books. from the Armenonville Tea Rooms, Brussels. HUIZEN (340.9 metres) 4 kW.-Transmits on 1,852 Programme from Elementary English Lesson. 6.26, Intermediate metres from 5.40 p.m.-12.10, Concert of Trio Music. 830, Voxhaus. 11.30 (approx.), Lesson. Close Down. English 6.45 Pianoforte Solos. 7.0 Selec- 2.40, Programme for Children. 5.10, Gramophone ' tion of Columbia Gramophone Records. 7,30, " Radio - Selections. 6.10 Talk. 0.20, Gramophone Selections. BERLIN (Voxhaus) (484 metres) : 4 kW. -9.10 a.m., Chronique." 8.15, Concert arranged by " La Meuse." 8.30, Catholic Bulletin. 6.40, Market Prices. English Lesson. 7.10, 9.15 a.m., Weather Report, News and 9.0, Topical Talk. 9.6, Concert (Continued). 1010, Lesson in Dressmaking. 7.40, Talk by M. L. J. N. Time Signal. 10.0 a,m., Programme of Gramophone News and Esperanto Report. 10.15, Orchestral Feber. 8.0, Concert of Orchestral Music. Choral Records. 10.30 a.m., Exchange Quotations. 11.65 Concert from the Palace Hotel, Brussels, 110 Selections and Soprano Solos. a.m., Time Signal. 12.30, Weather Report and News. (approx.), Close Down. 1.0, Programme of Gramophone Records. 2.0, Ex- KALUNDBORG (1,153 metres) ; 7 kW,- Programme change Quotations, Agricultural Report and Time BUDAPEST (556.6 metres) : 20 kW.- -4.10, Pro- also for (337 metres). of Stories. Selection Copenhagen 8.30 a.m., Morning Signal. 2.30. Talk, by Herr W. Mehlan. 3.0, Reinhold gramme 4.45, of Tzigane Music. Gymnastics. 10.0 a.m. Weather Report. 2.0, Pro- 8.0, Italian Lesson. 8.40, Hints for Wireless Amateurs. Stahl, Talk : Rembrandt. 3,30, Gertrud Isolani gramme for Children. 2.30, Concert of Instrumental reads from her own Works. 4.0, Orchestral Concert: 7.80, "1 Pagliacci " -Opera in Two Acts (Leon- and Vocal Selections. 5,20, Herr Frantzen, Talk: Selection from Carmen (Bizet) Waltz from Gipsy cavallo). 8.45. Gramophone Selections. 10.0, Selec- Galileo Galilei. 5.50, Report. News tion of Tzigane Music from the Hotel Britannia. Weather 6.0, Love (Lehár) Serenade mblancholique (Tchai- and Exchange Quotations. 6.15, Time Signal. 6.30, kovsky) ; Selection from Madame Butterfly (Puccini) ; CRACOW (568 metres) ; 1.5 kW. -6.0, Programme Ruth Sieverts, Talk : Women Abroad. 7.0, Chimes In a Spanish Town, Valse triste (Sibelius) ; Elegie relayed from Warsaw. 0.0, Miscellaneous Items. from the Town Hall. 7.5 ( approx.), " Hamlet " : (Bullerian) ; Ave Maria (Schubert) ; Merry Christmas 8.25, English Reading by M. Jean Stanislayskyy. Drama in Five Acts (Shakespeare) Danish Translation (Rhode) ; In the Interval, Advertising Notes. 6.0, 6.56, Time Signal. 7.0, Agricultural Report. 7.6 by Edv. Lembcke. Introductory Music by Brass Prof. Esau Jena, Talk : Short Waves. 8.30, Prof. Hans Mr. J. Regula, Talk : Foreign Politics of the Past Band. Canzona (Florentio Maschera, 1593). Sonata Delbrück, Talk : The Relation of the various forms of Week. 7.30, Programme relayed from Warsaw. (Giovanni Gabrieli, 1597). Followed by News. 9.0, Government to War aryl Peace. 7.0, " Der Mann in 9.30, Concert from a Restaurant. 10.80 (approx.), Concert of Light Music by the Station Orchestra: der Operette," by Else Knepel (Soprano), Bernhard Close Down. Chinese March, Kwang -Hsu (Locke) Selection Batel (Tenor), and the Station Orchestra. 8.30, Talk from Rose Marie (Friml-Stothart) ; Waltz ( Kollo); Call 2RN (319.1 ; 1.5 kW. on Journalism. Followed by News, Time Signal and DUBLIN, metre.) -1.30, Pizzicato Gavotte (Borregaard) ; Copenhagen Pictures Weather Report and Gramophone Selections. 7.20, Sports Notes. 9.30, Dancing Lesson, followed by Dance in Music (Lumbye) ; Intermezzo, Kadettenstreiche News. 7.30, Mr. E. C. FitzHenry, Talk : New Year Music. 11.30 (approx.), Close Down. (Jessel) ; Blues from Jowly spielt auf (Kpenek). Customs. 7.45, Irish Lesson, by Seamus O'Duirinne. 10.0, Dance Music from the Industri Restaurant. BERN (411 metres) 1.5 kW-8.29, Time Signal and 8.0, Selections from French and German Opera by the 110, Chimes from the Town Hall. 11.5 (approx.), Weather Report. 6.30, Reading by Herr Max v. Augmented Station Orchestra. 8.30, Irish, English Close Down. Kaenel. 7.0, Popular Concert arranged by the and Scotch Ballads by May Mortell (Mezzo -Soprano). Bern Chüejerjodler. 8.20, Selections by the Kursaal 8.40, Tenor Solos by Victor Cole. 8.50, The Station KATTOWITZ (422 metres) ; 10 kW. -3,p, Gramo- Orchestra. 8.45, News, Announcements and Weather Orchestra. 9.0, Scotch Ballads by Annie Broadhurst phone Selections. 4.10, Music Lesson by Prof. F. Report. 9.0, Selections by the Kursaal Orchestra. 9.15, Instrumental Selections by Edmund Burke. Sachse. 4.35, Children's Letter Box. !.o, Programme 9.35, Dance Music. 11.0 (approx.), Close Down. 9.30, Sketch by Elizabeth Young and Company. for Children. 6.0, Announcements. 6.30. Talk. 10.0, Selections by the Station String Orchestra. 6.56, Time Signal and Agricultural Report. 7.5, BRESLAU (322.6 metres) ; 4 kW--3.0, Review of Talk by Mme. M. Szczepanska. 7.30, Programme Books. Concert of Dance Music. 10.20, The Augmented Station Orchestra. 10.30, News, re- 3.30, 5.0. Fihn Weather Report and Close Down. layed from Warsaw. e.0, Weather Report and News. Review 5.25, Alfred Hanuschke, Talk in Esperanto : 9.30, Dance Music. The Silesian Town of Grünberg. 5.35, Herr Gerhard FRANKFURT (428.6 metres) ; 4 kW. 2.5, Concert : Haebler, Talk : The Land and Inhabitants of North Folk -song, Heilige Nacht (Reinhardt) ; Stille Nacht 1 MINAS (2.000 metres) ; 7 kW. -3.30, Musical China 6.20, Shorthand Lesson. 6.50, Herr E. (Mohr) ; Alle Jahre wieder (Hey) ; Süsser die Glocken Selection. 3.45. Talk. 4.30, Announcements. 5.0, Buchwald, Talk : Insurance. 7.15, Concert : Over- (Kritzinger) ; Weihnacht, wie bist so schön ; Schlaf Weather Report and .sews. 5.15. Agricultural Report. ture to Die Prinzessin von Trapezunt (Offenbach) ; wohl, du Himmelsknabe (Schubert) ; Folk -song, Still, 5.45, Musical Interlude. 6.0, Aviation Report. 8.30, Waltz, Jonathan (Millöcker) ; Selection from A Still ; Gloria, Gloria (Enclin) ; O, Come All Ye Concert : Orchestral Selections, (a) Overture to the Night in Venice (Joh. Strauss) ; Polka- Mazurka, Der Faithful (Reading). 2.55, Hints for the Housewife, by Vampire (Marschner), (b) Andante from The Jupiter erste Liebestraum (Delli ger) ; Selection from The Fini Pfannes. 3.35, Orchestral Concert of Operetta Symphony (Mozart) ; Selection for Baritone, Bass Bird Fancier (Zeller) ; Overture to La Belle Galathée Music. 5.10, Reading from Kurd Lasswitz' Novel, and Tenor from Faust (Gounod) ; 'Cello Solos, (a) (Suppé); Intermezzo from A Thousand and One "On Two Planets," by O. W. Studtmann. 6.30, The Chant du menestrel (Glazoünoff), (b) Minuet (Glaz- Nights (Joh. Strauss) ; Overture to Fesche Geister Letter Box. 5.45. Esperanto Lesson by W. Wischhoff. ounoff) ; Fantasia on Wagner's Tannhäuser (Hamm) ; (Ziehrer) ; Schützenliesel -Marsch (Eysler) ; Waltz 6.15, Otto Specht, Talk : The National Hunting Selections (Micheli), (a) Sonnen Untergang, (b) Mond - from Die geschiedene Frau (Fall) ; March from The League. 6.45, Astronomical Talk by Prof. Edmund schein Serenade, (e) Des Tages Erwachen, (d) Morgen- Chocolate Soldier (Oscar Straus) ; Waltz, Mädi Sittig. 7.1.6, Programme relayed from Stuttgart. sonne; The liaban in Algiers (Rossini) ; Sel coons B 30

www.americanradiohistory.com DECEMBER 26th, 1928. Wtshoo Wald 86z Programmes from Abroad. SCHENECTADY, Call 2XAD and 2XAF (21.90 and - ; 31.4 metres) 30 kW.-- (Renée) (a) Romance, (b) Serenade ; Hungarian Saturday, December 29th. 11.58, Weather Report. 12.0 Midnight), Phil Spitalny's Musical Dances Nos. 1 and 2 (Brahms) ; Lage di Garda Programme, relayed from New (Morena) ; International Suite ( Tchaikovsky). York, 12.30 a.m. (Sunday), Musical All Times Programme relayed from Rochester. 1.30 a.m., LAHTI (1522.8 metres) 35 kW. -4.0, Orchestral are reduced to Greenwich Musical Selections. 2.0 a.m., Selections by the Male Selections : The March of the Gnomes (filon) ; Con- Octet, relayed from New York. 2.30 a.m., Selections Mean Time and are p.m. except by Mildred cert Overture (Keler Béla) ; Strandidyllen Fétras); Hunt and the Marimba Orchestra. 3.0 Selection from Der Orlov (Granichstaedten). 4.35, a.m., " Lucky Strike " Programme, relayed from New Agricultural Talk. 5.15, Orchestral Selections Over- where otherwise stated. York. 4.0 a.m., Time Signal. 4.2 a.m., Dance Music ture to Ilka (Doppler) ; Acceleration Waltz (Strauss). by the Orchestra of the Hotel Ten Eyck, Albany. 5.40, Talk. 6.0, Evening Entertainment. 7.45, News 5.0 a.m. (approx.), Close Down. in Finnish and Swedish and Close Down. OSLO (461.5 metres) ; 1.5 kW.-Programme relayed SEVILLE, Call EA T5 (375 metres) 2 kW. -9.0, LANGENBERG (468.8 metres) ; 20 kW.- Programme by Fredriksstad (434.8 metres), Hamer (555.6 metres), Concert; Paso- doble, Belmonti.o (Prieto) ; Largo also for Aix-la- Chapelle (4t.0 metres), Cologne (283 Notodden (411 metres), Peregrnnd (500 metres), and (Tartini) ; Overture to I: Oasis (Corrin) followed by metres), and Münster (250 metres). -12.5, Concert : Rjnken (448 metres). -5.0, Programme for Children. Programme relayed from Madrid, E.AJ7, with Inter- Overture to The King of Athens (Zeh) ; Air from A 8.0, Birthday Greetings. 8.15, Weather Report and ludes by the Station Orchestra. 12.0 Midnight Life for the Czar (Glinka) ; Waltz, Evening Star News. 6.30 to 11.45, Christmas Programme. 8.30, (approx.), Close Down. (Lanner) 'Cello Solos, (a) Song without words Concert by the Station Orchestra. 8.30, Weather (Berbuto), (b) Minuet (Werkmeister), (e) Largo (Werk- Report and News. 8.45, Talk by a Journalist. 8.0, STAMBOUL (1 200 metres) ; 5 kW. -3.30, Concert. meister) ; Ballet Music from La Gioconda (Ponchielli) ; Dance Music from the Hotel Bristol. 11.45 (approx.), 5.30, Market Prices Report 5.15, Concert of Turkish Song, Wenn nicht Frühling war (Eysoldt) ; Selection Close Down. Music. 7.30, Weather Report and Time Signal. from Donnerwetter, tadellos (Lincke) ; March, Die 7.40, Vocal and Orchestra! Concert : Orchestral Wachtparade (Blankenburg). 1.30, Household Hints. PARIS (École Supérieure), Call FPTT (458 metres) ; Selections, (a) Overture to Don Juan (Mozart), (b) 2.0, Programme for Children. 2.40, Arthur Wurbs, 0.5 kW. -5.0, Relay of the Pasdeloup Symphony Selections from Néron (Boito) ; Songs, Orchestral Talk : The Foundations of Wireless Technique. Concert from the Champs Elysées Theatre. 8.30, Selections, (a) Le Chant du Berger (Wagner) ; Walzer 3,0, Eva Eichbauer, Talk : The Woman Worker in " Radio -Journal de France." 8.0, Talk by M. aus der Serenade (Tchaikovsky) ; The Entry of the Poetry. 3.30, Helmut Jaro Jaretzki, Talk : Heinrich Geville, Sports Notes and Review. 8.15 Talk by Gods into Valhalla (Wagner) ; Marche Militaire No. 1 Zille. 4.0, Talk. 4.20, English Lesson by Prof. Hase. M. Cépède. 8.30, Concert, followed by Time Signal, (Schubert). 9.0, News. 4.45, Gramophone Selections. 5.30, Prof. Boersch- Weather Report, News, Announcements and Dance mann, Talk : Chinese Architecture and Landscapes. Music from the Coliseum ile Paris. 12.0 Midnight STUTTGART (379.7 metres) ; 4 kW. -5.0 Time Signal 8.15, Talk for Workers : Lay Justice in Penal Law. (approx.), Close Down. and Weather Report. 5.15, Legal Talk by Herr L. 8.40, Prof. Hessen, Talk on Psychology : What do we Leibfried. 5.45, Talk relayed from Karlsruhe. 8.15, know of the Soul ? 7.0, Variety Programme. 9.30 PARIS (Eiffel Tower), Call FI. (265.0 metres) 5 kW. Herr A. M. Grzywienski, Talk : Oahu, or a day on a (approx.), News, Sports Notes, Commercial Announce- -5.0, Relay of Debate arranged by the Confederation Hawaiian Island in the South Seas. 8.45, Time ments, Orchestral Selections and Dance Music. 12.0 of Intellectual Workers. 7.10, Weather Report. Signal and Sports Notes. 7.15, Concert : Seranade Midnight, Close Down. 7.30, " Le Journal Parlé." for String Instruments (Reger) ; Serenade -n F Major (Glazounoff) ; Serenade (Novak). 8,30, Wireless ; LEIPZIG (385.8 metres) 4 kW. -3.30, Concert by Cabaret : Orchestral Selection, Pierrot March (Bose), PARIB (Petit Parisién) (340.9 metres) ; 5 kW,- the Station Orchestra. 4,45, Wireless News and Talk. Heut ist heut ! (Obermeyer) ; Es 8.45, Gramophone Selections, Talk, News and An- braucht ja nicht 5.20, Weather Forecast, Time Signal and Labour gerade Frühling zu sein (Blum) ; Ging da nicht eben nouncements. 9.0, Concert : Symphonic Prelude to Market Report. 5.30, Programme relayed from das Glück vorbei ? (Lehár) ; Italienisches L'Etranger (d'Indy) ; Polonaise for 'Cello and Or- Ständchen KSnigawusterhausen. Greff, Talk : - ; 6.0, Josef Psycho chestra (Casadesus), conducted by the Composer. (Capua) Mascaron (Benes) ; Musikanten (Salten) ; Analysis. 6.30, Herr Emil Oschatzt Talk: The Flirtation (Steck) ; Rothaarig ist mein 9.25, News and Announcements. 9.30, Symphony Schätzelein. Secrecy of the Telegraph and Postal Services. 7.0, Song (Steinbach) ; Duet, Lache mir zu l (Benatzky) ; Concert : Variations symphoniques for Piano lch Recital by Elena Gerhardt. 8.0, Orchestral Concert: and kann dei grünes Seidenkleid nicht leiden (Struve); Orchestra (Franck) ; Molto vivace from the Ninth Overture to A Night in Venice (Strauss -Korngold) ; Veronica ; Symphony (Beethoven). 10.0, News and Concert: (May) Grossmama, lass dir die Haare Intermezzo and Barcarolle from Tales of Hoffmann schneiden (May) ' Krause versus Lange " -Play Orchestral Suite (Saint -Satins) ; Danseuses des Delphes (Offenbach) ; Waltz and Polonaise from Eugen (Senff- Georgi) ; Orchestral Selection, Schwarz u, from the Preludes (Debussy) ; Onegin (Tchaikovsky) ; Selections from Fantasia on two The Barber of Angevin Airs (Lekeu). Weiss (Rot) ; followed by News and Dance Musc. Bagdad (Cornelius) ; Selections from Undine (Lort- zing). 9.0, News, Announcements and Sports Notes. TOULOUSE (Radiophonie du Midi), (389.8 metres) . 8.30, Dance Music from PARIS (Radio -Paris), Call CFR (1,750 metres) 6 8 Selections from " P Pleas et Mélisande relayed Voxhaus. 12.80, kW.- 12.45, " kW.- Concert of Columbia Gramophone (Debussy). 8.0. Exchange Quotations, Market Prices, Records : MADRID (Union Radio), Call EAJ7 (434.8 metres); Tango, Nostalgia, Dolores ; Fox -Trot, News and Announcements. 8.30, " Faust " -Opera Yum, Yuso, Yum ; 3 kW. 7.0, Chimes and Exchange Quotations, Waltz, Together ; Fox -Trot, (Gounod), relayed from the Capitol Theatre, Toulouse. Boublitshki ; followed by Sextet Concert : Selections from (a) La Fox -Trot, Rag -Doll ; La bede amie est In the Intervals, News and Announcements. 10.15. chula de Pontevedra (Luna and Bru), (b) Don Juan morte (Gounod) ; Paysage (Hahn) ; Pastorale North African News. 10.30 (approx.), Close Down. (Mozart), (c) La Hebrea (Estela) ; Interlude by Luis (Franck) ; in the Interval, News and Announcements. Medina. 8.0, Dance Music from the Alkázar. 8.25, 2.0, Market Prices and Religious Information. 3,45, VIENNA (517.2 metres) : 15 kW. -3.15, Concert : News and Announcements. 9.45, Market Report. Dance Music by the Joss Ghislery Symphonians. lu Overture to Phèdre (Massenet) ; Waltz, Herbst - 10.0, Chimes, followed by " La del soto ciel parral " the Intervals, News and Announcements, 8.30, stimmen ( Lincke) The Nutcracker Suite (Tchai- Agricultural Musical Play (Soutullo and Vert). Followed by News Report. 6.45, Musical Selections. 7.30, kovsky) ; Serenade ( Grünfeld); Kinematographie and Announcements. 12,30 a.m. (approx.) (Sunday), Pianoforte Lesson by M. Pierre Lucas. 8.0, Talk in Tönen (Ertl) ; Musica Proibita (Gastaidon) ; Close Down. arranged by the Union des Grandes Associations Selection from The Merry Widow (Lehár) ; Fest- Françaises, followed by Market Prices and News. stimmungsmarsch (Stix). 5.0, Dr. Paul Stefan, Talk : MILAN, Call 1MI (549 metres) 7 kW.--6.55, Time 8.15, Concert arranged by " Le Matin " : Petite Hector Berlioz, on the 125th Anniversar 01 his Signal and Announcements. 7.15, hidustrial Notes by Suite (Borodine) ; Sounnia Pisnia (Akimenko- Death. 5.30, Chamber Music : String Quartet No. 1 G. Ardau. 7.25, News. 7.30, rime Signal. 7.32, Chapelier) ; Promenade Sentimentale (Flament) ; in A Major (Borodine) ; Quartet Movement in C Symphony Concert : Overture to Manfred (Schu- Melopée dans le soir (Duhamel) ; Le Barbier de Minor (Schubert). 5.45, Ludwig Bäte reads from his mann) Symphony in D Major (Sinding) ; Literary Trouville (Lecocq) ; In the Intervals, News and own Works. 7.0, Time Signal, Weather Report and Talk by Umberto Morucchio ; Concerto in D Major for Announcements. News. 7.5, Musical Review of Old Vienna (Skurawy). Violin (Beethoven) Andantino all' antica (Marl- Followed by Dance Music and Phototelegraphy 'nazi) Nocturne (Martucci) Antiche arm e Danze POSEN (344.8 metres) ; L5 ksi'. -3.45, Programme Transmission. (Respighi). 9.55, News and Economic Notes. 10.0, of Classical German Music for Piano : Passacaglia Relay of Tzigane Orchestra from the Fiaschetteria (Handel) ; Sarabande (Handel) ; Sonata in A Major VILNA (435 metres) 1.5 kW. -4.10, Concert by Toscana. 10.45 (approx.), Close Down. (Mozart). 4.15, Talk on Boy Scouts. 4.35, Pro- Military Orchestra. 4.35, Programme relayed from gramme from Warsaw. 5.0, Programme front Warsaw. 5.0, Concert (continued). 5.25 Poem MOTALA (1,380 metres) ; 30 Programme Warsaw. kW.- also 8.0, Programme for Women. 8.20, English Lesson. Recitations by Mme. Hating Zawadzka. 5.40, Soprano for Stockholm (454.5 metres), Böden (1,190 metres), Talk on Song Recital by Mme. Swiecicka. 6.10, News. 6.30, Göteborg (416.5 metres), 8.45, Cinema Stars. 7.10, Miscellaneous Malmô (260.9 metres), Oster - Items. 7.30, Programme from Warsaw. Time Programme relayed from Warsaw. 7.0, Humorous sund (7211 metres), Sundsvall. (545.6 metres).-4.0, 9.0, Signal and News. 9.30, Cabaret Programme. 11.0, Selecti.ns. 7.80, Programme relayed from Warsaw. Concert of Light Music. 5.0, Programme for Children. Concert 10.30 (approx.), Close Down. 5.45, Cabaret Programme relayed arranged by the Maison Philips. LO a.m. from Göteborg. (approx.) (Sunday), Close Down. 8.45, Pianoforte Recital by Algot Haquinius ; Inter- WARSAW (1,111 metres) ; 10 kW. -44.10, Talk, mezzo marziale (Palmgren) ; Romance (Hinton) ; followed by " Chrstmas Carols " Short Historical 5 -A Prelude in G Major (Rachmaninoff) ; Prelude in E PRAGUE (348.9 metres) ; kW.- -4.30, Talk : The with Musical Illustrations. 4.35, Talk. Art of in Review 5.0, Major (Rachmaninoff) ; In the Autumn (Moszkovsky). Observation the Legal Profession. 4,40, Programme for Children. 6.0, Miscellaneous Items. 7.0, Dance Music with Vocal Interludes. Programme for Workers. 4.50, Agricultural Report. LO S.M. German Programme. 6.30, Wireless Review by M. H. Stepovsky. 6.58, (approx.) (Sunday), Close Down. 5.0, 8.0, Recital by Tambourine Time Signal. 7.0. Agricultural Report. 7.30, "'the Orchestra. 6.45, Talk : Reminiscences of Old Prague. Castle of Czorszty Musical Play in Three Acts Call Christmas Programme. "- NAPLES, 1NA (333.3 metres) ; 1.5 kW. -7.30, 7.0, 8.10, Sélection of Popular (Kurpinski). 9.u, Aviation Notes and Weather Wireless Talk. 7.40, Announcements. 7.50, News. Music. 9.0, Time Signal, News and Theatre Report. Dance Report. 9.5, News and Announcements. 9.20, 7.55, Harbour Notes. 8.0, Time Signal. 8.2, Variety 9.25, Music, relayed from Bratislava (300 metres). Police Report and Sports Notes. 9.30, Dance Music. Programme : Orchestral Selection, Overture to La 10.30 (approx.) Close Down. Belle Heléne (Offenbach) ; " L'Alba, Il Giorno e la ROME, Call 1EO (447.8 metres) ; 3 kW.-4.30, notte " Comedy in Three Acts (Dario Niccodemi). Concert of Vocal and Instrumental Selections. 6.50, ZURICH (583 metres) ; 1 kW. -4.15 Concert of In the First Interval: Orchestral Selections (Long.') Time Signal, Wireless Talk, and Announcements. Accordian Selections. 4.45. Weather Report and (a) Tramonto, (b) Le campane di S. Petronio. In the 7.10, Sports Notes, News, Exchange Quotations and Exchange Quotations. 5.0, Selection of New Gramo- Second Interval: Orchestral Selections (Siede), (a) Weather Report. 7.29, Time Signal. 7.80, Inter- phone Records.. 6.0, Chimes from the Zurich Churches. Ballata primaverile, (b) In Siviglia. 9.0, Talk and national Labour Office Report, 7.45, " Othello," 6,15, Time Signal and Weather Report. s.17, Popular Announcements. 9.50, News. 9.55, Calendar and Opera in Four Acts (Verdi). In the- Intervals, Review Concert. 7.30 (approx.), Concert of Humorous Songs Frogramnte Announcements. 10.0 (approx.), Dance of Art and Literature by Lucio D'Ambra and Talk to the Lute and Selections l'y the " Elite " Music Music from the Trocadero. 10.30 (approx.), Close for Wooten by Mme. Pompadour. 9.50, News. Corps. 9.0, Weather Report and News. 9.10 Gramo- Down. 10.0 (approx.), Close Down. phone Selections of Dance Music. B 31

www.americanradiohistory.com 862 DECEMBER 26th, 1928. G`7©II)Ilhl Programmes from Abroad. - rom the Copenhagen Town Hall. 7.5, Concert. Concert BARCELONA (Radio Barcelona), Call EMI (344.8 SUNDAY, DECEMBER 30th. 9.0 by the Copenhagen Station Orchestra, devoted to National Music by Fröhlich, Gade metres) ; 1.5 kW.-11.0 a.m., Relay of Cathedral and Chimes. U.5 a.m., Weather and Forecast Lumbye. 9.45, Dance Music by the Orchestra at Report the Palace Hotel, conducted by Teddy Petersen. followed by Aviation Route Conditions. 1.30, Con- In the cert by the Iberia Trio with Gramophone Records at All Times are reduced to Greenwich Interval at 11.0, Chimes relayed from the Intervals. 2.45 Copenhagen Town Hall. 11.30 (approx.), Close to 5.30, No Transmission. 5.30, Down. Deming Signal followed by Relay of an Opera from Mean Time and are p.m. except the Gran Teatro de Liceo. In the Interval : Market Prices and Exchange Quotations. where otherwise stated. KATTOWITZ (422 metres) ; 10 kW. -9.15 8.0 to 8.20, Trans- Relay of Morning mission arranged by the Catalonian Institute of Service. 10.56 a.m., Time Signal. 11.0 a.m., Weather Report and Forecast. 11.15 a.m., Agriculture at San Isidro. 8.20, Concert by the Popular Barcelona Station Orchestra. Suite, Les de Concert by the Kattowitz Station Quartet. Danses CORK, Call 6CK (400 metres) ; 1.5 kW.-8.30 Vocal 1.0, Talk. 1.20 and Two Talks for Farmers. Chez Naua ( Jacquet -M mton). (a) Berceuse et Carillon 140, and Instrumental : Lillois. Concert Selections by the All 2.0, Weather Report and Forecast. 2.15, Relay of (b] Volte de Prpvence. (c) La Dérobée Ireland Trio. 11.0, National Anthem and Weather Philharmonic Symphony Bretonne. (d) Bourrée d'Auvergne. (e) Danse Concert from Warsaw. Report and Forecast. 11.15 (approx.), Close Down. 5.0, Concert. 6.0, Miscellaneous Announcements. Alsacienne. 8.40 Sports News. 9.0 ( approx.), Close Down. 8.20, Half-hour of Humour by Professor St. Ligon. CRACOW (566 metres) 1.5 kW. -9.15 a.m. to 6.56 Time Signal. 7.0, Talk, under the auspices of BERGEN (370.4 metres) ; 1.5 kW. -9.30 am., Relay 10.45 a.m., Relay of Cathedral Service. 10.56 a.m., the Pedagogical Institute. 7.30, Concert relayed of Church Service. 11.30 a.m., Weather Report and Relay of Fanfare from the Church of Notre Dame, from Warsaw : The Polskie Radio Orchestra, Im- Forecast and Genera] News Bulletin. 4.0, Orchestral followed by Time Signal and Weather Report and promptu in B Flat Major, Op. 14.2, No. 3.(Schubert). Concert. 7.0, Concert by the Station Orchestra. Forecast. 11.10 a.m., Relay of Philharmonic Concert 9.0, Weather Report and Forecast, News from the 7.50, Talk on the Week's Happenings. 8.0, Pianoforte from Warsaw. LO and 1.20, Agricultural Talks. Press and Sports Notes. 9.30, Dance Music. 10.30 Recital by Maja Hjort Wemmestead. Compositions 1.40, ' La Chronique Agricole," by Dr. St. Was - (approx.), Close Down. by Glück, Brahms, Chopin and Schumann. 8.30, niewski. 2.0, Weather Report and Forecast. 2.15, Musical Programme. 9.0, Weather Report and Fore- Cauce: t relayed from the Philharmonic Hall at Warsaw. KAUNAS (2,000 metres) : 7 kW. -2.30, Programme cast, Late News Bulletin and Time Signal. 9.15, 4.20, Talk. 5.0, Concert relayed from Warsaw. for Children. 3.0, Half-hour for Young People. Dance Music. ILO (approx.), Close Down. 658, Time Signal from the Observatory. 7.0, Relay 8.80, Talk on a Health Subject by Dr. Jurgelionis. of Fanfare from the Church of Notre Dame, followed 4.0, Talk by J. Ardickas on Economics and Daily BERLIN (Königswusterhausen) (1649 metres) ; 40 by Sports Notes. 7.30, Concert of Vocal and Instru- Life. 4.50, Weather R port and Forecast and News kW. -7.55 a.m., Garrison Church Chimes relayed mental Music : Duet from " Carmen " -Opera from the Press. 4.55, Talk with Lithuania, and from Potsdam. 8.0 a.m., Musical Recital and Address (Bizet) by Mademoiselle Raczynska and M. Demar- Polish News. 5.35, Concert of Popular Music, followed relayed from Voxhaas, followed by Chimes from the Mikuszewski. At the Piano : M. 13. Wallek- Walewski. by Miscellaneous Items. 9.0 (approx.), Close Down. Berlin Cathedral. 10.30 am., Programme of Music 9.0, Late News Bulletin from Warsaw. 9.30, Concert relayed from Voxhaas. Experimental Trans- 12.45, relayed from a Restaurant. 10.30 (approx.), Close KÖNIGSBERG (303 metres) ; 4 kW.- Programme mission of Pictures. 1.30 to 2.25, Three Agricultural Down. relayed by Danzig (272.7 metres). -8.0 am., Recital Talks from Voxhaus. 2.30, Reading of Stories from of Sacred Music with Soloists and Address in the Voxhaus. 3.0, Talk. 3.80, Musical Prcgramme. 5.0, DUBLIN, Call 2RN (319.1 metres) ; 1.5 kW. -8.30, interval. 10.0 (Königsberg only), Weather " Deutsche a.m. The W elle " Series of Talks, followed by Programme relayed from Cork. Mezzo -Soprano Solos Report and 'Forecast. 10.5 a.m., Morning Concert. Relay of Concert or Opera. 9.15, Press News. 9.30, by Miss G. Gallagher. 1L0, National Anthem and Relay 11.0 am., Concert by the Station Orchestra. 11.55 of Dance Music. 11.30 (approx.), Close Down. Weather Report. 11.15 (approx.), Close Down. a.m., Time Signal relayed from Nases, followed by Weather BERLIN (Voxhaus) (484 metres) ; 4 kW. -7.55 a.m., Report and Forecast. 3.15, Orchestral GENEVA (760 metres) ; 1.5 kW. -9.0 a.m., Relay Selections. 7.30, Concert by the Königsberg Station Chimes relayed from the Garrison Church at Potsdam. of Service and Address from the Victoria Hall, Geneva. Orchestra conducted by Dr. Rolf Himsler : Ballet 8.0 a.m., Morning Concert of Vocal and Instrumental 7.15, The Day's Sport by M. Vieux, Sports Editor Music and Address, followed by Relay of Climes from Music from " La Gioconda " by Ponchielli. 9.15, of the " Geneva Tribune." 7.25, Service relayed Late News Bulletin and Sports Results. 9.30, Dance the Berlin Cathedral. 10.30 a.m. ( approx.), Orchestral from the Temple de Caronge. 8.0, Concert in the Concert with Solcists. LO, Lesson in Morse for Be- Music. 11.30 (approx.), Close Down. Studio by the Geneva Wireless Orchestra : Fantasia ginners by Hans W. Priwin. 1.30 to 2.25, Programme on Popular Russian Melodies (Léopold). of Talks on Farming. L30, Prac tical Hints for thz LAHTI (1,522.8 metres) ; 35 kW.- Progranmre also Farmer. 1.45, The Weekly Markets and Weather for Helsingtors (375 metres). -8.0 a.m., Relay of Conditions. L55, Chat on an agricultural topic. 2.30, HAMBURG, Call HA (in Morse) (394.7 metres) ; Church Service. 9.50 a.m., News from the Press. Reading of Stories. 3.0, Talk. 3.30, Recital of Music. 4 kW.- Programme relayed by Bremen (272.7 metres), 10.5 a.m., Musical Selections. 10.50 a.m., Weather 6.0, Talk. 8.30, Talk. 7.15 (approx.), Concert of Play Hanover (2117 metres), and Kiel (254.2 metres). - Report and Forecast and Time Signal. 11.0 a.m., 7.25 a.m., Time Signal. 7.30 a.m., Weather Report Relay of Church Service (in Swedish). 3.0, Concert followed by Weather Report and Forecast, Late News and Bulletin and Sports Results. 9.30, Dance Music. Forecast, followed by General News Bulletin. by the Lahti Station Orchestra conducted by Erkki 11.30 (approx.), Close Down. 7.60 a.m., Talk. 8.0 a.m., Weekly Legal Notes. Linko. Selection from the Opera, " Pique Daum" 10.0 am., Talk. 11.55 am., Time Signal relayed (Tchaikovsky). 3.50, Talk. 4.10, Concert by the from Nanan. 12.5 (for BXZIERS (158 metres) ; 0.6 kW. -8.30, General News Hamburg and Kiel), Concert. Station Orchestra. 4.30, Talk. 4.57, Time Signal Bulletin. 8.45, Concert arranged by the Maison 12.5 (for Bremen), Musical Selections. 12.5 (for and Weather Report and Forecast. 5.10, Concert by Relin -Minoles at Béziers. Selections of the Pathé Art Hanover), Gramophone Records. 1.0, Entertain- the Wireless Orchestra. 5.30, History Talk. 6.0, Records. 10,30 (approx.), Close Down. ment for Children. 6.30, Transmission arranged by Concert of Popular Selections. 7.45, General News the School of Physical Training in Hamburg. 6.40, Bulletin given in Finnish. 8.0, News Bulletin in Sports Notes. BORDEAUX (Radio Sud -Ouest) (238 metres) ;1 kW.- 6.55, Weather Report and Forecast. Swedish. 8.30 (approx.), Close Down. 12.30, The Latest Gramophone 7.0, Play. 8.30, Concert oI Songs and Dance Tunes Records. 1.45, Close of 0z8. In the interval at Down. 9.30, Weather Report LANGENBERG (468.8 metres) ; 20 kW.-Programme and Forecast and Late News Bulletin. 10.50 also for Aix -la- metres), Cologne (for and Chapelle (400 (283 BRESLAU (322.6 metres) ; 4 kW.-Programme re- Hamburg, Bremen Kiel), Weather Report metres) and Münster (250 metres). --8.45 a.m., Lesson keyed by Gleiwitz (329.7 metres).-8.15 a.m., Chimes and Foreca,t for the North Sea and Baltic. 11.0 in the Art of Self Defence by Dr. Ludwig Bach. relayed from Christ Church. 10.0 a.m., Catholic (approx.), Close Down. 7.20 a.m., Summary in Esperanto of the Week's Recital of Choral Music, with Address in the Pri grammes by Alfred Dormanns. 7.35 a.m. interval. 110 a.m., Concert with Soloists. LO, HILVERSUM (1,071 metres) ; 5 kW.- 12.10, Concert to 7.55 a.m. Esperanto Lesson by Alfred by the Hilversum Station Trio. Dormans. Guessing Competitions. 110, Talk. 1.35, Hints for the 1.40, Concert. 8.0 a.m., Relay of Church Chimes. 8.5 am., Catholic Chess Player by Adolf Kra i r 2.0, Programme for 2.55 Concert by the Wireless Orchestra, conducted Morning Recital of Choral and Instrumental Music Children. 2.30, Talk for Farmers. 2.55, Concert. by Ñico Treep : 'Cello Solos by Thomas Canivez with Address in the Interval. 10.0 Talk by and Pianoforte Solos by Jeannette Walen. a.m., &35, Talk. 4.5, Concert. 6.50, Talk. 7.15, Concert 7.40, Fritz Worm : The Worth and Honour of the German by the Band of the Seventh Infantry Regiment, con- Time Signal. 7.42, General News Bulletin, Weather Language. 12.0 Noon, Concert of Orchestral Music Report and Forecast and Sports News. 7.55, Opera. ducted by Herr Heifer. Overture to Lvsistrata, 1.30, Talk. 3.30, Concert : Stories of Karl Löwe operetta by Lincke. 9.0, Late News Bulletin. 9.30, 10.40 (approx.), Close Down. about the Christ-Child. 6.35, Sports News. 7.0, Programme of Light Music. 11.15 (approx.), Close Play followed by Late News Bulletin, Sports Notes HUIZEN (340.9 metres) ; 4 Transmits Down. kW.- from and Concert. 11.0 (approx.), Close Down. 5.40 on 1,852 metres. -8.5 am., Sacred Service. BRUSSELS (508.5 metres) ; 1.5 kW. -5.0, Orchestral 9.30 a.m., Relay of Morning Service. 12.10, Concert Selections relayed from the Armenonville Tea Room, of Trio Selections. 1.10, Talk. 1,40, Talk. 2.10. LEIPZIG (365.8 metres) ; 4 kW.- Programme re- Brussels. 6.0, Programme for Children arranged by Orchestral Concert. 5.15, Relay of Evening Service layed by Dresden (275.2 metres). 7.30 a.m., Organ the Theatre des Enfants, and under the direction of from Almelo (on 1,852 metres), Sermon by the Minister, Recital. 8.0 a.m., Vocal and Instrumental Concert. M. Léon Leroy. 6.30, Musical Programme. 7.30, Le the Rev. W. L. Milo. 7.10, Talk. 7.50 (approx.), 10.0 a.m., Talk. 10.30 am., Talk. 11.0 a.m., Musical Journal Parlé de Radio- Belgique. 8.15, Concert or Concert of Orchestral Music. 10.25, Choral Epilogue Programme. 12.0 Noon, Agricultural Talk. 12.30, Play. 10.15, Late News Bulletin and News from the under the direction of Mr. Jos. H. Pickkers. 10.40 Talk. L0, Gleanings from the Foreign Press. 1.45, Evening Press. 11.0 (approx.), Close Down. (approx.), Close Down. Wireless Talk. 2.15, Gramophone Records. 3.0, Concert. 6.30, Talk. 6.0, Talk. 6.30, Christmas (J. S. by Alfred COLOGNE (283 metres) ; 4 kW.- Programme also for KALUNDBORG (1,153 metres) ; 7 kW.- Programme Oratorio Bach), conducted Szendrei: Aix-la- Chapelle (4u0 metres), Langenberg (468.8 also for Copenhagen (337 metres). -9.0 a.m., Relay Soloists- Lotte Mäder-Wohlgemuth (Soprano), Martha metres) and niünater (25u metres). -6.45 am., Boxing of Divine Service from Copenhagen. 10.30 am. Adam (Contralto), Hans Lissmann (Tenor) and Kurt Wichmann (Bass). 9.0, Sports News and News from Instruction by Dr. Ludwig Bach. 7.29 am., to 10.40 a.m. ( lalundborg only), Weather Report Weekly Programme Review in Esperanto by Alfred and Forecast of the Meteorological tusttute, at Copen- the Press. 9.80, Dance Music relayed from Berlin. Dormans. 7.3.1 a.m., Esperanto Lesson by Alfred hagen. 12.0 Noon to 12.25, German Lesson for 11.30 (approx.), Close Down. Dormanns. 8.0 a.m , Church Chimes. 8.5 am., Beginners arranged by " Radiolytteren." 12.30, Catholic Festival of Music with Address in the Interval. Elementary French Lesson, arranged by " Radio - LYONS (Radio Lyon) (291 metres) 1.5 10.0 am, Talk by Fritz Worm on the German Lan- lytteren." 2.0, Concert of Instrumental Music. The Radio Lyon " Journal Parlé with General guage. 120 Noon. Orchestral Concert. 1.30, Talk. 4.0, Relay of Church Service from Copenhagen. 5.20, News Bulletin and News from the Press. 8.0, instru- 3.30, Concert. u.35, Sports News. 7.0, "The Magic Programme for Children. 5.50 (Kalundoorg only) mental Concert with Pianoforte Solos by Madame Flute," Musical Play n Two Act; by Mozart. Followed Weather Report and Forecast from the Copenhagen Ducharme and Violin Solos by M. Camand of the by Lai News Bul.etm, Sports Notes and Musica Meteorological Institute. 6.0, News from the Press. Lyons Conservatoire : Selection from ' L'Arlésienne" Programme. 11.0 (approx.), Close Down, 6.15, Time Signal. b.30 Talk. 7.0, Chimes relayed Suite by Bizet 9.0 (approx.), Close Down. B 32

www.americanradiohistory.com e DECEMBER 26th, 1928. WIMSDSMO 863 WDYild Programmes from Abroad.- from New York. 12.0 Midnight, The Old Company's Programme, relayed MADRID (Union Radio), Call EAJ7 (434.8 metres) ; Sunday, December 30th. from New York. 12.30, a.m, 1.5 kW.- Programme relayed by Salamanca (EAJ22) (Monday) Relay from the Capitol Theatre, New York. (405 metres).-2.0, Relay of. Chimes and Time Signal. 2.0 a.m., Talk on the United States Government by 2.5, Concert by the Station Orchestra with Violin the Editor of " The United States Daily," relayed All Times are reduced to Greenwich from Washingtom, D.C. 2.15 a.m., Atwater Rent Solos by Celso Diaz and Selection by Luis Medina in Programme, the interval, Romanza Andaluza (Sarasate). 3.30 to Mean Time and are p.m. except relayed from New York. 3.15 a.m., 7.0, No Transmission. 7.0, Chimes. 7.5, Concert by Correct Time. 3.17 8.m., Programme of the Nationl the Union Radio Sextet and Selection by Luis Medina. where otherwise stated. Light Opera Company, relayed from New York. 8.0, The Palermo Orchestra at the Alkazar in a pro- 4.15 a.m., Experimental Transmission of Television gramme of Dance Music. 8.30 to 10.0, No Transmis- Signals. 4.30 a.m. (approx.), Close Down. sion. 10.0, Chimes and Time Signal. 10.5, Concert by a Military Band. 12.0 Midnight, Relay of Chimes 8.30, " Le Radio Journal de France." 8.0, Sports TOULOUSE (Radiophonie du Midi) (389.6 metres) 8 by Palermo Talk and Results. Talk under kW.- 12.30, Weather Report and Forecast and Local followed by Dance Music the Orchestra 8.15, the auspices Market playing at the Alkazar. 12.30 a.m. (approx.) (Monday), of the Union of French Associations. 8.30, Orches- Report. 12.45, Concert of Vocal and Instru- Close Down. tral Concert, arranged by the General Association of mental Music. 1.0, Time Signal. L5, Concert (con- French Wireless Listeners. 10.30 (approx.), Relay tinued). 1.45, News from the Daily Papers. 8.0, Stock Exchange Quotations from Paris and MILAN, 1MI (519 metres) ; 7 kW. -9.0 a.m., Opening of Dance Music from the Coliseum de Paris. 12.0 Local Signal and Instruction in English. 9.30 a.m. to (Midnight) (approx.), Close Down. Market News. 8.15, News from " La Dépêche " and 10.15 a.m., Vocal and Instrumental Concert of Sacred "Le Petit Parisien." 8.30, Concert arranged by "L'Association des Commerçants Radio- Electriciens Music. 11.30 a..m, Time Signal. 11.35 a.m., Concert PARIS (Eiffel Tower), Call FL (2,650 metres) ; 5 kW.- du Midi " : Selections from Carmen Bizet. by the Milan Station Quartet. 12.30 to 3.0, No Trans - -7.56 a.m., Time Signal on 32.5 metres. 9.28 a.m., by In the mission. 3.0, Opening Signal. 3.5, Variety Concert. Time Signal on 2,650 metres. 5.0, Relay of Pasdeloup interval at 9.0, Time Signal. 10.15, News from North 4.30, Light Music by the Orchestra at the Fiaschetteria Concert. 7.10 to 7.20, Weather Report and Forecast. Africa and Late News Bulletin. 10.30 (approx.), Close Toscana. 5.0 to 6.55, No Transmission. 8.55, Opening 7.30, " Le ,journal Parlé par T.S.F.," with Talks by Down. Signal. 7.0, News and Announcements. 7,15, History regular contributors, Dr. : Pierre Vachet Portez - VIENNA Talk by C. A. Blanche. 7.25, Sports News. 7.30, vous bien. 7.56, Time Signal on 32.5 metres. 8.0 (517.2 metres) ; 15 kW.- Programme re- layed by Graz (357.1 metres), Innsbruck (294.1 metres), Time Signal. 7.35, Relay of the Opera " La Leggenda to 9.0, Orchestral Concert with Vocalists. 10.26. delle sette Torri' by Alberto Gaseo. At the end of Time Signal on 2,650 metres. Klagenfurt (272.7 metres), and Linz (254.2 metres)..-r- 11.15 (approx.), 9.20 a.m., Organ Recital. 10.0 Concert by Act Two : Sports Results and News from the Stefani Close Down. a.m., the Agency. 10.30 (approx.). Close Down. Vienna Symphony Orchestra with Soloists. 2.15, Experimental Transmission of Pictures. 3.0, Orches- PARIS (Petit Parisien) (340.9 metres) ; 0.5 kW.- tral MOTALA (1,380 metres) ; 30 kW.- Programme also 8.45, Popular Gramophone Concert with Soloists. 7.0, Time Signal, Weather Selections. 8.50, Talk. Report and Forecast and General News for Stockholm (454.5 metres), Boden (1,190 metres), 8.55, News from the Press. 9.0, Instrumental Concert Bulletin. (416.5 metres), metres), 7.5, " Love's Labour Lost," Comedy in Five Acts by Göteborg Malmö (260.9 with Soloists. 9.25, General News Bulletin. 9.30, Shakespeare, Ostersund (720 metres) and Sundsvall (545.6 metres). - The Symphony Half Hour, conducted by Professor Translated into German and produced by 10.0 a,m., Relay of Service from a Church in Stock- Estyle of the Paris Stefan flock. Followed by Relay of Dance ltusle and Conservatoire. 10.0, Late News Experimental Transmission of Pictures. holm. 3.0, Musical Programme. 4.0, Children's Bulletin. 10.15, Orchestral Concert. 11.0 (approx.), 10.30 Entertainment. 4.55, Chimes relayed from the Town Close Down. (approx.), Close Down. Hall at Stockholm. 5.0, Relay of Evening Service. 7.0, " The Merry Widow " (Lehár). 8.15, General PARIS VILNA (435 metres) ; 1.5 kW.-9.15 a.m. to 10.45 (Radio Paris), Call CFR (1,750 metres) ; 0 a.m., Relay of Morning Service from a Cathedral. News Bulletin and Weather Report. 9.30 (approx.), kW. -8.0 a.m., General News Bulletin and News front Close Down. the Press. 10.58 a.m. to 4.20, Programme relayed from Warsaw. 8.30 a.m., Physical Instruction by Dr. 10.58 a.m., Time Signal followed by Fanfare from the Diffre. 12.0 Noon, Religious Address, followed by Church of Notre MUNICH (535.7 metres) ; 4 k \V.- Programme relayed Dame at Cracow. 1L6 a.m., General Sacred Recital arranged by " La Vie Catholique." News Bulletin. by Augsburg (506 metres), Kaisers] aitem (277.8 metres) 12.30, Press News. 11.10 a.m., Symphony Concert of the 12.45, Concert by the Albert Warsaw Philharmonic Society. LO to Three Talks and Nuremberg (241.9 metres). -10.0 a.m., Chimes Locatelli Orchestra. 4.30, Gramophone Selections 2.0, relayed from the Munich Town on Agricultural Matters. 2.15, Orchestral Concert. Hai. 10.10 a.m., The arranged by " : L'Industrie Musicale." In the interval 4.20, Talk. 5.0, Gramophone Records. 5.20, Pro- Wireless Weather Chart for Bavaria. 10.50 a.m., Time Press News. 8.30, Agricultural Talk. 6.45, Gramo- Signal followed by Weather Report and Forecast. gramme for Children. . 45, Selections of Zither Music phone Records. 7.30, Press News. 7.45, The Radio - by 11.0 a.m., Concert. 12.5, Time Signal and Weather Paris Professor Witolo Jodko. 6.58, Time Signal. Circus. 8.15, Concert of Symphony Music, 7.0 to 10.30, Programme relayed from Warsaw. 7.0, Report and Forecast followed by Announcements of under the direction of M. Eugéne Bigot. In the Forthcoming Programmes. 2.0, Musical or Literary Talk. 7.30, Concert of Orchestral Music conducted by intervals : News from the Evening Papers and Late J. Dworakowski: Madame Trombini; Kazuro, Programme. 4.0, Concert by the iMünich Wireless Trio. News Bulletin. 10.30 (approx.), Close Down. 7.5, " Die Schöne Helena," Operetta by Offenbach. Pianoforte Solo, Nocturne in E Minor (Chopin). 9.0 News followed Aviation Route Report and Weather Report and 9.20, Late Bulletin by Relay of Concert. POSEN (344.8 metres) ; 1.5 kW. -9.15 a.m. to 10.45 11.0 (approx.), Close Down. Forecast. 9.5, News Bulletin from the Polish Tele- a.m., Relay of Sacred Service. 11.0 a.m., Time graph Agency. 9.20, Sports News and Police Report. Signal. 11.5 a.m. and 11.30 a.m., Two Talks on NAPLES. Call 1NA (333.3 metres) ; 1.3 k\V. -8.30 9.30, Dance Music relayed from the " Oaza " Res- Farming Topics. 2.15, Symphony Concert relayed taurant, Warsaw. 10.30 (approx.), Close Down. a.m., Elementary Lesson in French by Professor from Warsaw. 4.20, " Silva reruns," by Mr. B. Etienne Verdier. 9.0 a.m., Sacred Concert. 3.45, Busiakiewicz. Talk. 4.45, 5.25, Programme for WARSAW (1,111 metres) ; 10 kW.-9.15 a.m. to Children's Corner. 4.0, Variety Concert. 4.30, Time Children. 6.0, Transmission arranged by the League Signal. 7.30, News of the Day. 7.50, Report of the 10.45 a.m., Morning Service from a Cathedral. 10.50 of Polish Youth. 6.20, Talk, relayed from Warsaw. a.m., Time Signal: 11.0 a.m., Relay of Fanfare from Naples Harbour Authorities. 8.0, Time Signal. 6.45, Talk. 7.10, Twenty Minutes of Variety Items. 8.2, Concert by the Naples Wireless Orchestra and the Church of Notre Dame at Cracow. 11.5 a.m., 7.30, Concert. 9.0, Time Signal. 9.5, General News Aviation Route Report and Weather Report and Soloists : " Pietoso al par del hume " from " La Bulletin. 9.20, Lesson in Dancing by Mr. Favorita " (Donizetti), Duet for Mezzo-Soprano and Starski. Forecast. 11.10 a.m., Philharmonic Symphony Con- 9.40, Dance Music relayed from the Carlton Restaurant. cert arranged by the Magistracy of Warsaw. 1.0 to Tenor, accompanied by the Orchestra. Sung by 11.0 (approx.), Close Down. Signora Ada Testa and G. Ferrero. 9.0, Sports Notes. 2.0, Three Talks on Agriculture. 2.0, Weather Report 9.55, Calendar and Summary of Forthcoming Pro- and Forecast. 2.15, Relay of Concert of Symphony RIGA (528.3 metres) ; 4 kW. grammes. 10.0 (approx.), Close Down. -9.15 a.m., Relay of Music by the Warsaw Philharmonic Society. 4.20, Morning Service (in I.atvian) from the Mara Church. Talk. 4.45, Aviation Talk. 5.0, Concert by the Polskie Songs, 12.0 Noon, Tales and Music for Children. Radio Orchestra conducted by J. Ozininski : OSLO (461.5 metres) ; 1.5 Programme Overture kW.- relayed 2.0, Two Talks. 3.0, Concert by the Riga Wireless to Norma, Opera by Bellini. 6.0, Variety Items. by Fredriksstad (434.8 metres), Hamer (555.6 metres), Orchestra, under the direction of Arved Parups. Notodden (411 metres), metres), Porsgrand (500 4.0 to 5.30, Four Talks. 8.0, Concert of Popular 6.20, Talk. 6,45, General News Bulletin. 6.56, Time Rjukan (448 metres). -9,20 a.m., Chimes. 9.30 a.m., Selections conducted by Janis Medin : Selections from Divine Service relayed Signal. 7.0, C. Jablonowski, Talle : Divertissements from St. Saviour's Church. The Tales of Hoffmann (Offenbach). 8.0, Weather intellectuels. 7.30, Concert by the Polskie Radio - Chimes. Relay of 4.50, 5.0, Service from St. Saviour's Report. 8.30, Concert relayed from the Café de Orchestra. 9.0, Aviation Report and Weather Report Church. 6.15, Weather Report and Forecast, followed l'Opera. 10.0 (approx.), Close Down. and Forecast. 9.5, Communications from the Polish by Piss News. 6.30, Talk. 7.0, Time Signal. 7.5, of Telegraph Agency. 9.20, Police Report and Sports Concert Christmas Music. The Station Orchestra, ROME, Call 1RO (447.8 metres) 3 kW. -8.30 a.m., conducted by Hugo Kramm News. 9.30, Relay of Dance Music from the " Oaza " " The Children's Opening Signal, followed by German Lesson for Restaurant. 10.30 (approx.), Close Down. Christmas " (Kling). 8.30, Weather Report and For - Beginners. 9.0 a.m., Vocal and Instrumental Recital. cast and News from the Press. 8.45, Talk by a 9.45 a.m. to 12.0 Noon, No Transmission. 12.0 Noon, ZAGREB (309.2 metres) ; 0.7 kW. -10.0 Journalist on the Day'sTopics. 9.0, Musical or Literary Opening Signal. 12.5 to 1.0, Concert by the Radio Concert of Symphony Music by the Croatian Phil- Programme. 9.30, Relay of Dance Music. 11.30 Trio. 1.0 to 4.0, No Transmission. 4.0, Opening (approx.), Close Down. harmonic Society, under the direction of Oskar Nedbal : Signal. 4.5 to 5.30, Variety Concert. 6.50, Opening Fire Worship and \Votan's Farewell (Wagner). 4.0, Signal, followed by News and Announcements. 7.10, Programme of Dance Music relayed from the Club - PARIS (École Supérieure), Call FPTT (458 metres) ; Talk for Farmers. 7.15, Sports Results and News Cabaret. 6.45, Talk on a Wireless "Topic. 7.0, Relay 0.5 kW.- Programme relayed at intervals by the from the Stefani Agency. 7,29, Time Signal. 7.31, of an Opera from the National Theatre, Zagreb. In following stations : Bordeaux PTT (275 metres), Talk. 7.45, " La Chaste Susanne," Operetta in Three the intervals: General News Bulletin and Weather Eiffel Tower (2,650 metres), Grenoble (416 metres) Acts. Music by Gilbert, with the Station Orchestra Report and Forecast. 10.0 (approx.), Close Down. Lille (264 metres), Limoges (285 metres), Lyons PTT and Choir. Talk in the interval. 9.30, Late New (480 metres), Marseilles (303 metres), Rennes (280 Bulletin. 10.0 (approx.) Close Down. ZURICH (588 metres) ; 1 k \V. -10.0 a.m., Programme metres), Toulouse Pr'r (260 metres). -8.0 a.m., of Light Music. 1L29 a.m., Weather Report and General News Bulletin and Time Signal. 9.25 a.m., SCHENECTADY, Call 2XAD and 2XAF (21.98 and Forecast. 11.30 a.m.. Concert by the Zürich Wireless International Time Signal and Weather Report. 31.4 metres) ; 30 kW. --4,0, Relay of Sacred Service. Orchestra. 3.0, Concert by the Castellano Orchestra 12.0 Noon, Concert. 1.0, Le Journal de France 8.30. Relay of Organ Recital by Elmer A. Tidmarch, playing at the Carlton Elite Hotel. 6.30, Time Signal Economigne. 1.30, Concert organised by the General from the Union College Memorial Cahpel at Schenec- and Weather Report and Forecast. 6.33, Religous Association of French Wireless Listeners. 2.30, tady, N.Y. 9.0, Dr. S. Parkes Cadman's Address to Address. 7.0, Violin Recital by Fred Rothpletz, of of Relay Symphony Concert from the Concert Halt Men relayed from New York. 10.30, Instrumental Cologne. At the Piano : Otto Strauss. 9.0, Weather of the Paris paper " Le Journal." 4.0, Pasdeloup Programme relayed from New York. 11.0, The Report and Forecast, Late News Bulletin and Com- Symphony Concert relayed from the Théâtre des American Legion Band in a Concert relayed fronts munications from the Neue Züricher Zeitung. 9.80 Champs Elysécs, conducted by M. Ahené Baton. Boston. Mass. 11.80, The Acousticon Programme (approx.), Close Down. B 33

www.americanradiohistory.com 864 WRpsll@EA DECEMBER 26th, 1928. Wogild

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W.W. ABAC N9 19 STAGE 2 USEFUL DATA CHARTS (No. 19, STALE 2). An explanation of this abac was given in the text accompanying Useful Data Charts (No. 19, Stage 1). B 34

www.americanradiohistory.com DECEMBER 26th, 1928. 'WIpcfleog 865 MOAT

By Our Special Correspondent. Royalty at the Microphone. -Fewer Oscillators. -More about " Broadcasting House." - Radio Drama Demonstration. -A Queer Kink. -" Carnival."

The Prince of Wales. In the previous year, the proportion highest in January and February, which If all goes well, listeners will hear was 35- per cent., but at that time only suggests that new listeners were experi- H.R.H. the Prince of Wales broadcasting meagre details of each complaint were encing difficulty in operating their Christ- through all stations, including 5GB, on then available, no set form of questions mas presents. The lowest mark was Christmas Day. His Royal Highness, who having been framed. Nowadays every reached at holiday time in July and will make a personal visit to Savoy Hill, correspondent who complains of local August. is to speak at 7.25 p.m. for ten minutes on The number of anti -oscillation pam- behalf of the Miners' Distress Fund. phlets issued up to the present is 822,529. 0000 0000 Royal Broadcasters. Gael Warning. The past year has been notable for the The Glasgow Gaelic Choir will be heard number of broadcasts by Royalty. H.M. in a National Gaelic Concert which the the King was heard on July 10th at the B.B.C. is broadcasting from all its Scot- opening of new University buildings at tish stations on January 9th. Nottingham and again on October 10th, 0000 when His Majesty inaugurated the new Tyne Bridge. The Prince of Wales has Signs of Liie. addressed the microphone on several occa- The hoarse cry of the housebreaker can sions, while on December 12th Her still be heard on the Portland Place site, Majesty the Queen broadcast for the first but last time I visited the spot there time, when unveiling the Merchant Sea- were already signs of better things to be. men's memorial. A new hoarding has been erected, with no 0000 chinks in it. A New Contact. It is unlikely that constructional work There can be no doubt that broadcast- will actually begin for at least two ing has established a new contact between months, and I understand that a tre- the Royal Family and the nation-much mendous amount of work must be clone stronger than in the days when royal before the foundation stone can be laid. personalities were known to the majority As is generally the case, the " founda- of people merely through the medium of tion " stone will be situated on ground " pretty pretty " postcards and blurred level and must await the completion of pictures in the papers. the foundations. 0000 0000 The Decline in Oscillation. No Foundation Stone? The humble oscillator has been rather Whether or not an elaborate foundation forgotten of late, except by those who ceremony will be arranged is not yet de- are not allowed to forget him, cided upon. A rite of this kind should but Savoy WHERE THE SUN STILL SHINES. A Hill has been on the watch, and some glimpse of the Juan les Pins broadcast- afford an opportunity for a good " O.B." rather surprising statistics have been pre- ing station at Nice, which sometimes However, it rests with the owning syndi- pared showing that oscillation can be heard in England, though the cate to say whether they desire the name the family power is only 0.5 kilowatt. The wave- has diminished considerably during 1928. length is 245 metres. of the B.B.C. to be perpetuated on what 0000 is not B.B.C. property. Perhaps there Oscillation oscillation will be no foundation stone, save the in- When is Very Local. receives a questionnaire iu tegrity of the contracting parties. From December 1st, 1927, to November which every available detail can be tabu- 0000 30th, 1928, 2,037 cases of oscillation were lated. referred by the B.B.C. to the Post Office. c000 Architectural Revisions. Of this number, 1,445 were dealt with by Mr. Tudsbury, the B.B.C.'s civil engi.` the Post Office engineers, and in nearly Fractious Christmas Presents. neer, is in close touch with the architect, 17 per cent. of the cases the fault was The total number of complaints dealt Colonel Van Myer, and already several found to lie in the complainant's own re- with by the B.B.C. during the past year alterations in the original design have been ceiver. was 9,006. The " curve " was at its agreed upon. In the first place the rather B 35

www.americanradiohistory.com 866 WAp@hoo DECEMBER 26th, 1928. Wordlcd diminutive entrance way shown in the realism. Apparently they can be more succumbed to the spell of radio drama. architect's drawing is to be widened and than real to some people, for I have just His most famous novel " Carnival " has extended in height to the top of the first heard of a listener on the South Coast been adapted to the microphone by Holt floor. More windows are to be added at who suffers with a morbid dread of hear- Marvell, with the assistance of the the top of the central block. ing Big Ben. He cannot account for this novelist himself. It has been suggested that the basement little mental " kink,' but confesses that The " first night " will be on January should form a large garage for the cars as midnight approaches he has an uncon- 8th, when " Carnival " will be broadcast of artists and Corporation officials. A trollable desire to switch off the dance from 5GB. On the following evening it garage of some sort certainly seems called music before the first stroke from West- will go out from 2L0, 5XX, and other for, as anyone will agree who has had to minster. stations. thread his way through the variegated 0000 Episodes of the story will be linked up collection of cars which is never absent Fodder for Radio Drama. by narrative much in the same way as in from the cramped little streets around I suppose a psycho- analyst would sug- Conrad's " Lord Jim," but in this case Savoy Hill. gest that it is all due to an anti- Govern- Mr. Compton Mackenzie will be his own 0000 narrator. ment complex, the patient being sub- 0000 European Visitors. Forty London rose to the occasion a few days FUTURE FEATURES. Characters. ago when members of the Union Inter- " Carnival " treats of the life of Jenny London and Daventry. appears in every scene and nationale de Radiophonie held their De- DECEMBER 30TH.- Service from White- Raeburn, who cember meetings at B.B.C. headquarters. field's Tabernacle, Tottenham Court has about half of the entire dialogue. An especially interesting demonstration Road. The part of Jenny will be taken by Elsa DECEMBER 31sT. -" 1928 -1929." Another favourite in the staged for their benefit was the produc- JANUARY 2ND. -" The Passing of the Lanchester. tion of a radio play, using the drama con- Third Floor Back." caste will be Mabel Constanduros. JANUARY 3RD. -" Bethlehem," a nativity Altogether there will be about 40 char- trol board which has proved so valuable play by Laurence Housman, music in plays like " Speed," " Love," and by Joseph Moorat. acters, which must be something of a others entailing the use of many studios. JANUARY 4TH.-" The Charcoal Burner's record in radio plays. Sou," an operetta by L. du Garde 0000 There is no similar control board in Peach, music by Victor Hely- existence either in Europe or America. Hutchinson. Time Signals. 0000 Daventry Exp. (5GB). The B.B.C. time signals are to follow DECEMBER 31sT. -New Year's Party, Radio Drama relayed from ' Pattison's Café a new schedule as from January 1st. The primary business of the delegates Restaurant, Birmingham. Here is the revised table :- of JANUARY 18T." The Passing the : 10.30, 1.0, 4.45, 6.15, 10.0. was concerned with the compilation of Third Floor Back." Week -days programmes, statistics, and the exchange JANUARY 3RD.-Selections from " Falka," Sundays : 10.30, 3.30, 9.0, 10.0. of information regarding dramatic works Chassaigne's comic opera. Gale Warnings. -Week -days : 1.0, 4.45, suitable for broadcasting. The meetings Cardiff. 6.15; Sundays : 3.30. JANUARY 5111. -A Concert for Blind and 0000 were under the chairmanship of M. Oscar Disabled Soldiers and Blind Workers, Geiga (Austria), the other delegates being provided by the Marquis and Mar- An Elder o' the Kirk. Professor Dr. Richtern (Austria), M. chioness of Bute. Anyone interested in Scottish drama Hubert (Belgium), M. Pollock (France), Manchester. JANUARY 18T.-Programme to celebrate knows that the first performance of a new Major Atkinson (Great Britain), M. the 35th Anniversary of the Man- work by Murray McClymont is something Szoets (Hungary), and M. Chamiec chester Ship Canal. to look forward to, and there are sure to JANUARY 5211. -A Musical Tour of Europe. (Poland). There were also present Dr. be many listeners in the North of Scot- Sourek (Czecho- slovakia), President of the Newcastle. DECEMBER 31ST. -" DO You Remember? " land who will make a special point of Juridical Commission of the Union, and a comedy by E. A. Bryan. having their sets tuned in to Aberdeen on Mr. Arthur Burrows (Secretary -General of Glasgow. January 7th to hear the first broadcast of the Union). DECEMBER 31ST.-" Hogmanay," a play by In one- 0000 Joe Corrie. his " Cupid and the Kirk." this Aberdeen. act Scots comedy Mr. McClymont is in A Schools Demonstration. JANUARY 1sT. -" 1928," a " memories " lighter vein than in his biggest works, programme. Special attention was given to the study Belfast. and he makes most amusing play with the of broadcasting to schools, and a Council DECEMBER 31sT.- Reminiscences of 1928. story of how an elder o' the Kirk deals school in London was visited during ari JANUARY 4T1í. -Versailles, " Theatre de la firmly but humorously with the petty in- actual transmission. I hear that this part Petite Galerie." trigues of a lowland village. The elder of the programme produced a great is played by Arthur Black. impression. consciously aware that the chime proceeds 0000 The next meetings of the Union will from the building in which (he thinks) Teaching a Difficult Art. be held in Genéva in February. the country's affairs are being so badly Payne, with the 0000 Be that as it may, are Billy Mayerl and Jack managed. there co- operating causes, leave B.B,C. Dance Orchestra, are The Bells, Bells Bells. other likely but I their in an illustrated talk identification to would -be radio dra- on January 10th Whether or not Tennyson set the vogue from 2L0 on " How to Play Syncopated may be doubtful, but bell ringing seems matists who are searching for something bizarre and sepulchral. Music." to take an indissoluble part in all celebra- 3 0 0 0 0000 tions for welcoming the New Year. On Strange Saturdays. A Rugger Relay, the night of December 31st and January The rugger match between England ist the B.B.C. will help the wild bells to A man whose job is a very dull one all in the and The Rest at Twickenham on January ring out farther than they did in Tenny- the week advertises personal of a running com- of the newspapers his willingness 5th will be the subject son's time. At 11.55 p.m. we shall hear columns mentary broadcast through 2L0 and 5XX. the muffled bells of St. Michael's, Corn - to " go anywhere and do anything " be- 0000 hill, rung by the Ancient Society of Col- tween noon and midnight on Saturdays. lege Youths. Then, at midnight, Big Ben The results are embodied in a series A Great Octogenarian. will be heard, and after the last reverbera- of light- hearted stories entitled " Six Sir Alfred Yarrow, the great ship- tions have died away the unmuffled bells Strange Saturdays." The author is Holt builder and head of Yarrow and Co., the the first of the series is to of _ Southwark Cathedral will burst out Marvell, and makers of the Yarrow boiler now gener- `with a merry welcome for 1929. be broadcast on January 12th. ally adopted by the navies of the world, 0000 0000 will give listeners his " Memories of A Queer Kink "Carnival." Eighty Years " in a broadcast from the Bells, and, indeed, all percussion in- Compton Mackenzie, who is already an London studio on January 1st. Sir struments, come through with astonishing ardent listener and a gramophile, has Alfred was born in 1842. B 36

www.americanradiohistory.com DECEMBER 26th, 1928. WIp@Il®00 867 /n WII& Grid Detection and Flat Tuning. Why is it that the grid circuit of a leaky grid " detector valve is fora R flatly tuned than when the anode F, bend system is used? I have heard it ascribed to the fact that the leak is damping the tuning coil, but this does not scent to be correct, as when I join a 2- megolun resistance across the input circuit of an anode bend detector, there is no noticeable change in sharpness of tuning. Again, it is said that flatness is due to the flow of grid current, but this I cannot understand; will you please zaU_\\\i.-U``((irt\111//®/1 explain? E. S. P. As you say, these explanations are not quitè satisfactory. The fact is that a valve de- " The Wireless rr a operating as a grid circuit World Supplies Free Service of Technical Information. tector actually takes energy from the The Service is subject to the rules of the Department, which are printed below; these circuit across which it is connected dur- must be strictly enforced, in the interest of readers themselves. A selection .of ing the time that the grid is made suffi- queries of general interest is dealt with below, in some cases at greater length than ciently positive (by the application of would be possible in a letter. signal voltages) to pass a current. popo A Sensitive Pick both between and between windings. -up. turns How to Neutralise. Why is it that I get a shock from the For an average valve, we suggest a pri- loud- speaker terminals of my receiver mary of 35 turns of No. 40 wire, spaced 1 have been attempting to balance a single -stage amplifier by follow- (1 -v -2) when out to occupy about one half of the second- H.F. using a gramophone pick- ing given time up, which is connected in the grid ary winding length. The average spacing the instructions from circuit of the detector valve? The between primary and secondary should be to time, to the effect that the filament is circuit of the valve should be broken. effect is not present when the set Unfortunately, at this distance from tuned to wireless signals. the B. K. transmitting station it is impos- C. sible to We can only assume the from hear any signals unless the that input H.F. valve filament is glowing. Can your pick -up is very much greater than you suggest anything you are able to get from the an alternative method of procedure? S. G. R. ether. You must remember that for The gramophone reproduction you are using operation of balancing a receiver is, thanks to modern improved methods, a three L.F. stages, so that the amplification comparatively is when is simple task, and there is no greater than the set perform- need to extinguish ing its normal we the H.F. valve fila- function. Incidentally, ment. All you to is would your H.F. amplifier have do to bring the suggest that tuned circuits near the point of reson- is probably not pulling its weight ; in your ance, when oscillation will normally be locality it should be possible thoroughly produced. to overload each valve from the detector Now rotate the balancing con- denser until it ceases ; readjust both tun- onwards on signals from either of the ing Daveutry transmissions. controls until signals are at maxi- coco mum, and if self -oscillation is still pre- sent, make a further Down Fig. 1.- Windings and connections of an slight adjustment of The Aerial Lead. H.F. transformer for screened grid valves. the balancing condenser. The set should I am told that the down lead of my aerial, now be stable, but if there seems from to -din. The disposition to be a which at present consists of bare cop- din. of tendency towards oscillation on another per wire, as used for the horizontal the windings and the external connections wavelength setting, it may be necessary of the transformer are given in Fig. 1. to portion, should be of rubber- covered 0000 make still another small adjustment of wire. Is this correct? R. L. S. balancing capacity. We know that this fallacious idea ex- A Charge -discharge Meter. ists ; it would be interesting to know how With reference to the article on " A Safe There is it gained currency. no need H.T. Supply " in your issue for De- RULES. whatsoever to use insulated wire for any cember 5th, is it possible to change (1.) Only one question (which must deal with part of the aerial up to the point where it the position of the manometer shown a single specific point) can be answered. Letters enters the building. Even if it is neces- in circuit (b) so that it indicates the must be concisely worded and headed " Infor- sary to attach a guy rope to the down current taken from the battery when mation Department." (2.) Queries must be written on one side of lead, the necessary isolation can best be it is working, as well as the current the paper, and diagrams drawn on a separate obtained by using an ordinary insulator. flowing when it is on charge? sheet. d self -addressed stamped envelope must 0000 D. C. B. be enclosed for postal reply. (3.) Designs or circuit diagrams for complete Modified H.F. Transformers. Yes, you can do this by inserting the receivers cannot be given ; under present -day Please describe the method of adding a meter in the lead from the switch to the conditions justice cannot be done to questions primary winding to a Litz secondary negative terminal of the battery; but un- of this kind in the course of a letter. (4.) Practical wiring plans cannot be supplied in order to make a transformer suit- less you obtain an instrument with a or considered. able for use with a screened grid H.F. centre zero, it will be necessary to fit a (5.) Designs for components such as L.F. valve. T. chokes, power transformers, etc., cannot be C. reversing switch for it. supplied. We assume that you refer to a single - It may be added that we do not greatly (6.) Queries arising from the construction or layer solenoid winding, as used in a num- care for the practice of keeping a meter operation of receivers must be confined to con- . ber of transformers described in this jour- in with slructionat sets described in " The Wireless permanently circuit an H.T. ac- World " or to standard manufacturers' receivers. nal. Probably the simplest and most cumulator battery on discharge as its re- Readers desiring information on matters effective way of converting this for use sistance is often quite enough to give rise beyond the scope of the Information Depart- with screened valves is to adopt the usual a certain of low- frequency ment are invited to submit suggestions regarding to amount subjects to be in type of primary winding, with spacing reaction. treated tutore articles or paragraphs. B 37

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www.americanradiohistory.com Wilpemo DECEMBER 26th, Ï928. Woad Filament Wattage The Best Wavetrap. The coil L may have about 30 turns of it has o/ en been stated that valves with The sclerti ,it y o/ nip .. Everyman Four" No. 24 D.C.C. wire, preferably wound on 2 -volt filaments are slightly less effi- receiver was adequate when I lived' a former of such a size that it may slide cient than their counterparts with a ten miles from the local station, but into the existing aerial -grid coil former. higher filament rating. Does this now, at a distance of 24 miles, I find These details are shown in Fig. 2 (b). apply to screened grid valves? that the number of stations receivable By varying the position between ab -, N. V. without interference is very much re- sorption and grid coils, it will be possible As with triodes, the efficiency of duced -this in spite of the fact that to find a point where interfering signals screened grid valves will be determined I am using a high -impedance, high- are " absorbed " over the desired band to a certain extent by the filament wat- magnification valve as an H.F. ampli- of wavelengths; it is not a difficult matter tage, amore, all other things being equal, fier. It is realised that the addition to decide on the best practical coupling those with the higher voltage rating will of an extra H.F. amplifier would by trial. be the better. With modern valves the overcome the difficulty, but this would You will note that a switch is con- difference is not very great, and, indeed, mean rebuilding the set, and I should nected in series with the tuned absorption it may be non -existent if the filament prefer to add a wavetrap. Will circuit, in order that it may be cut out when required. wattage of low -voltage valves is in- you recommend the best type? 0000 creased by designing them to take a 7. W. MmM. heavier current than those rated at There Long -wave Instability. higher L.T. voltages. can be little doubt that the ab- sorption wavetrap is the most suitable My receiver, with a single H.F. stage, c000 is in cases where it is desired to eliminate perfectly stable on the mediums i Reception on Headphones. the signals of a single station. The broadcast waveband, but on the long Will you recommend the best circuit for necessary additions are shown in the waves 1 find it impossible to obtain phone reception of the local station a " balance." The H.F. trans- (about three miles away) on an formers, which are of the inter- indoor aerial? H. B. L. changeable type are carefully con- No very elaborate set will be required structed and appear to be in perfect for this purpose, and we suggest that a order. Can you suggest any reason detector valve with leaky grid condenser for my failure? N. W. T. rectification and reaction will be quite We think it almost certain that your adequate. Maximum sensitivity will trouble may be traced to imperfect separ- hardly be necessary, so no special pre- ation of H.F. and L.F. oscillatory cur- cautions need be taken to choose the rents in the coupling between the detector most effective forni of reaction control. valve and the L.F. amplifier. If you 0000 have not taken the usual precautions, we An Invariable Rule. recommend you to do so. If you have, In a skeleton circuit diagram it items you should assure yourself that the com- customary to mark the connection ponents used as H.F. stoppers are in to the negative side of the grid bias order. For instance, a resistance may battery, but the point to which the possibly have a lower value than that at positive terminal of this battery is which it is rated. An H.F. choke used joined is often omitted. Can it be for this purpose should be of reasonably assumed that it will always be efficient design, and you should assure connected to L.T.? S. D. G. yourself that none of its sections is short- circuited. By -pass Yes, the positive side of GRID COIL condensers also 4 the G.B. bat- play an tery is always connected to the common important part in separating H.F. negative bus -bar In certain cases, where and L.F. currents, and you should mal-e special sure that one of these has not an inte-nui precautions are necessary to avoid disconnection. stray couplings, you will find that it is non o connected directly to the negative ter- minal of the valve; this only applies Eliminating Morse Interference when a separate battery is used for an you are probably aware, Morse later - individual valve. fercnre is a very serious probli in this part of the world. In an effort Two- Station Switch-over. to eliminate it, would it be really worth my while tv rebuild my re- Hare you published a description of a ABSORPTION three -valve set which would be suit- COIL (bi ceiver, adding a second B.F. stage? able for rereptiono/ the two Darentry - W. R. transmissions, and with provision for The extra selectivity afforded by an- changing from one to the other by Fig 2.-Connections of an effective absorp- other stage will tion wavetrap ; below ; a suAgeatcd method H.F. certainly bring means of a simple switch? If so, of coupling the CAI to an aerial -grid about an improvement, but, we fear, only will you please refer rne to the back transformer. to an extent which you will find disap- number in which the description ap- pointing. The trouble is that spark trans- peared? N. M. skeleton diagram given in Fig. 2 (a), mission -which is probably responsible We think that the " Quick Change from which you will see that a tuned cir- for the majority of the interference on Broadcast Receiver " described in The cuit (L, C, C,) is coupled to the low - the medium[ broadcast waveband - is Wireless World for February 16th should potential end of the aerial grid trans- flatly tuned, and cannot be completely meet your needs, as it has separate tuned former. It is important that this circuit eliminated by selective circuits. In any circuits for the two wavebands, with pro - should have low resistance, and it should case, we recommend you to concentrate vision for connecting either at will by be arranged to tune to the wavelength of your efforts very largely on the longer operation of a switch. At extreme ranges the interfering transmission with a coni- broadcasting wavelengths; admittedly the reaction control, which in this set is paratively high ratio of capacity to in- they are not free from Morse interfer- common to both wavebands, would not ductance; thus we suggest that C should ence, but the majority of transmitters on hold good with a single setting, but in he a fixed air dielectric condenser of these wavelengths make use of the con- your locality little or no reaction should 0.0005 mfd. in parallel with a variable, tinuous wave system, which is not respon- be necessary for reception of the desired C of the same capacity ; of course, a sible for so much interference as the stations. and we do not think any diffi- variable condenser of 0.001 mfd. could be spark stations, most of which operate on culty will he experienced on this score. used if preferred. shorter waves. s 38 of=

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