S g Experimenter's Licence for The Home-made Set ( p. 591) No. 26 SATURDAY, DECEMBER 2, 1922 Price 3d. Regular Regular Features Features RADIOGRAMS TELEPHONY TRANSMISSIONS 111 ON YOUR WAVE- LENGTH CLUB EVENTS la RI if 6c1 3 INFORMATION LETTERS BUREAU Photograph of a Single -circuit One -valve Set constructed by ETC.ETC. Mr. A. W. Owen, of Walthamstow si 111 SPECIAL ARTICLES Atmospherics or Statics Amateur Transmissions and the A Basket -coil Type Tuner G.P.O. Shall We Ever See by Wireless ? A Novel Utility Aerial Telephone Winding All About the Valve Loose -coupler Device Rectifying Panels for Unit Set InterferencePrevention emataitWttviess 582 DECEMBER 2, 1922 (1VIITCHELFONES ECONOMICELECTRICLTD. Are not a spasmodic production to meet A I a sudden demand, but have been on the I-1 Have YOU tried the market for over three months, and during this period 27,000 have been distributed " XTRAUDION " VALVE ? to thetrade, and consequently we have the latest and best development of not been able to offer them direct to the retail buyer. the 3 Electrode Valve. RECTIFIES, OSCILLATES 1,000per week are now available, and we announce AMPLIFIES Its Mechanical Construction DELIVERY FROM STOCK makes it a stronger and more lasting Youpostyourorder,orcallatour valve than any other. premises and get them at once.Think The Filament consumes well under what this means to you-you, perhaps, who half - an - amp. at 4 volts.Anode have been waiting and are stillwaiting. Potential, 50 volts. Standard resistance 4,000 ohms, double headgear with Its Amplifying Properties are double headstraps,comfortable,highlyefficient, wonderful and its freedom from noises and foolproof a revelation. Send for Descriptive Leaflet. 25/- per pair: 15/- 15/- Special Terms to Traders and deliveries that will surprise you, U PRICE PRICE PATENTS PENQINC MITCHELLS Electrical & Wireless Ltd.; We publish the most complete Wireless Postal Address: McDermott Road, Peckham, S.E.15. Catalogue obtainabie.36 pages, profusely Retail Address: 188, Rye Lane, Peckham, S.E.15. illustrated, and many usefulcircuitsfor Head (Vice 10, FITZROY experimental work. Mailed to any address 'Phones: New Cross 1540,1541. SQUARE, LONDON, W.I. on receipt of four penny stamps. Showrooms Telephone : LI)anch Showrooms 6. Works : cGREATBRITAIN'S GREATEST WIRELESS STORE-4(1) 303, EUSTON ROAD, N.W.I. MUSEUM 1055 TWICKENHAM ofInterest to Amateurs "PERRYPHONES" n Auction HEAD SETS FOR WIRELESS TELEPHONY Included in this important Sale of 4,000 ohms.! Ex -Government Wireless Apparatus 21 Every SetGuaranteed. Beautifully there will be a large number of finished, highly sensitive, detachable receivers, eminent!y suited for purchase SMALL LOTSby WirelessExperimenters IMMEDIATE DELIVERY THE TRADE will also have anexcellent opportunity of securing: Illustrated NVireless Catalogue now New Mark III Tuners,Mark III C.W. Trans- ready, post free, 3d. mitters and Receivers. B. Mark II2 -Valve Detector Amplifiers, 50 Watt Spark Trench THE JEARY ELECTRICAL CO., LTD., Sets for Receiving and Transmitting, 8, LAMBETH HILL, and 97, QUEEN VICTORIA ST., C. Mark III 3 -Valve Amplifiers (low frequency) in new LONDON, E.C.4. condition. Ind at Glasgow, Birmingham, etc. Brown's Head Telephones, Reed Type, 120 to 8,000 ohms in new condition. Valve Boxes, Teak Instrument Cases,a quantity of 13ft.Masts, '4181111111111111111111111111111111111111111111111111111111111111111111111111111111111818111181111111111111111111111111111111W and a large quantity of Miscellaneous WIRELESS GEAR. COMPLETE and EFFICIENT AERIAL SETS LTil = -F. STEVENS' AUCTION ROOMS --#: For Single Wire Aerial For Double Wire Aerial E= (Established 1760) 110 feet 7122s Copper Wire I E L--- 100 feet 7122s Copper Wire= = 2 Shell PatternInsulators, 4 Shell Pattern Insulators -.7.-7.. Will sell the above by Auction = which guarantee High 2 Hard Wood Spreaders, 174. :: attheir Great Rooms :: = Insulation 6 feet long E-- - 2 Wall Fixtures 2 Wall Fixtures = = or or 38, King Street, Covent Garden, E. 1 Wall Fixture and 1 Mast 1 Wall Fixture and 1 Mast g W .C.2. =-- WEDNESDAY, December 6th, 1922, E.= PulleyPulley E7.-. 10/complete 16/6 complete =E At 12.30 o'clock precisely _=_ =E Delivered Free' front Stock. Cash with Order = = Please state clearly whether you require 2 Wall Fixtures = OnView: Monday, 4th December, from 12.30 to 5.30, Tuesday H- or IWall Fixture and l Mast Pulley .; from 9.30 to 5.30, and on morning of sale from 9.30 to 12 o'clock = = =. = THE SOUTH WESTERNWIRELESS SUPPLIES CO. ;....-=-. CATALOGUES ON APPLICATION. 382a, Merton Road, - Southfields, - London, S.W. Telephone -1824 GERRARD. Telegrams-" Aces, RAND, T. ',CON." .-,- = RINNEIN111111i TI111111111111111111111111111111111111 11111111H1111111111111111111111111111111111111111111M11111111111111111111111111111111111Ti 5 63 and Etzctrics No. 26 December 2, 1922 ATMOSPHERICS OR STATICS OF late we have had several pessi- between.the dots and dashes, making mistsinour midst who have The elimination of atmospherics or statics is italmost impossible todistinguish beenpreachingdisaster bythe one of the most pressing needs of modern them. mighty -hand of static..They tell us wireless. This article explains the effects So faraswireless telephonyis thatwhenthebigbroadcasting andgivessome simplehintsthatmay concerned, however, I do not think stations begin on their long -delayed provide a key to the problem. that static will be found nearly .as programmes we shall begin tosee serious.In the first place wireless how undeveloped the science is as telephony is conducted by means of yet. They tell us to wait until we arepassage of the charge is recorded in thecontinuous waves, and where theseare listening -in on one of our favourite pieces,telephone receivers.These static chargesused in the ether we get sharp tuning, and in the midst of our enjoyment are sud-are so broad and cover so many differentwhich is in itself extremely helpful. denly enraged by a discordant jargon ofwave -lengths that they penetrate almost all Then again, we are dealing now with sound-static interference again. turning adjustments, this being, perhaps,voice and music sounds, and these vary Most probably you have met one of thesetheir most annoying characteristic. in pitch and amplitude, so that the hearer pessimists.He gives one the impression The peculiar thing about staticis thatdoes not have to concentrate on one pitch that our receiving sets will be useless untilitis most prevalent in tropical countries.and pick up dots and dashes.I believe some method is found of eliminating theIn northern latitudes it 'is most prevalentthat with careful tuning the voices and disastrous static.In fact, static is the bigin summer, and alWays worse during themusic will ride clear above the static, but bogy of the wireless world. night than during the daytime.Its effectof course, the tuning must be very dis- But up to the present we have not suf-upon the telephones ranges from harsh,criminate, and that only comes with ex- fered so badly from it,I think.Let usrasping soundsto mushy squeaks, andperience. see what static is and how it behaves, andwhen itisreally bad it continues unin- perhaps we may pick up a hint or two soterruptedly.Such are the conditions ofSome Hints that we may be able to combat its effects.static. Here are a few suggestions for use where static comes in very badly. Haw Static Behaves If you are using a two- or First we must realise that three -stage amplification in broadcastingisnot a new connectionwith a loud thing; the only new thing is speaker, forgo that pleasure the public. interest which is for a little while and cut now being taken in it. Ever out, the whole lot.By lis- sincethe development of tening -indirectfromthe the wireless telephone to a detector you will necessarily point of good performance, sacrificesomedegreeof amateurs have been broad- volume of sound, but you casting to one another, and willgainmuchinthe they have done it very well. clarity of the signals from Static has not seriously in- the headphones. Remember convenienced them so far. that the amplifying valves. The best way to explain extend their power toall static simplyisthatitis currents that come in, and lightning in the making.It thatstatic, being stronger consists of accumulated than theradio -frequencies, charges of electricity which isamplifiedto a greater arestoredintheatmo- volumethanthesignal. sphere, not large enough in sounds. capacity to break down the Another hint is to reduce, airresistance andfinda the amount of current pass-. Photograph of Four -valve Set of the Small Cabinet Type. Ix -ayto theearth. These ing through the valve fila-; Charges are stored up just (Telephone Manufacturing Co., Ltd.) ments to the lowest possible like charges on the plates amount consistent with the of a condenser, and; like the result of static, because the latter, some of the chargeleaksacross Static and Telegraph.), more current passed through the valve the the dielectric, or air. To wireless telegraphystaticoffersa more the static is increased in intensity as InthecaseOf static,thisleakage x-eryserious opposition.!The sounds ofcompared to the music. takes place along the aerials of wireless.'thecodeareveryI constant,and, this Above ,all, make all tuning. adjustment stations wherever they -are' erected, and theallows the atmospheric interference to getcarefully and very slowly. A. J. B. mateur WirettS5 584 DECEMBER 2,1922 A Neat Efficient Tuner A Compact Tuner of the Basket -coil Type ci THE followingisa description of ahalf inches for wave -lengths from 600 tonear itspin,as shown in Fig.5. The tuner of a neat and compact type andr,roo metres.The holders are made fromreaction coil consists of a small slab coil remarkable efficiency. ebonite in. thick, and are 3 in. long bymounted in the same manner as the basket The apparatus is mounted on an ebonite1% in. wide (see Fig. 3).Each. has a slotcoils, and is sufficiently small to prevent the panel 9 in. long by 5 in. wide and in. 743-ff in.wide cut lengthwise through theset from oscillating, while large enough to thick (see Fig.1). This is screwed on tothickness of the ebonite (see Fig.