MARCH 1979

Tape Slide Synchronizer Synthesizer Sequencer It's so easy for YOU to

I'm going to use the adjacent card to order obtain subscriptions, books, 40 binders and back issues acopy! from ETI! Only $3.00

There's got to be something in this book for all ETI readers. Canadian Projects Book Number One gives you twenty-five projects from issues of ETI sold in Canada.All the projects have been reworked since they were first published to update them with any information we might have received about availability of components, impr- ovements, etc. To order Canadian Projects Book Number One send $3.00 per copy + 4E4 for postage and handling to: Canadian Projects Book, ET! Magazine, Unit Six, 25 Overlea Blvd., Toronto, Ontario, M4H 1B1. Please do not send cash. Send a Cheque, Money Order, Master Charge, Chargex (Visa), please include Card No., Expiry Date, and Signature. Vol. 3. No. 3. MARCH 1979 Editor STEVE BRAIDWOOD BSc Assistant Editor electronics today GRAHAM WIDEMAN BASc international Advertising INCORPORATING ELECTRONIC WORKSHOP Advertising Manager MARK CZERWINSKI BASc Advertising Services SHARON WILSON Advertising Representatives JIM O'BRIEN PROJECTS Eastern Canada JEAN SEGUIN & ASSOCIATES INC.. 601 Cote Vertu. TAPE -SLIDE SYNCHRONISER 31 St. Laurent. Quebec H4L 1 X8. Keep the slides in step with the commentary, on one channel. Telephone (514) 748-6561 DUAL ELECTRONIC DICE 37 Subscriptions Department An LED game to keep you relatively honest. BEBE LALL SYNTHESIZER SEQUENCER 41 Accounts Department Automatic tunes, or control operation. SENGA HARRISON Layout and Assembly GAIL ARMBRUST Contributing Editors FEATURES WALLACE J. PARSONS (Audio) THE SPACE SHUTTLE 14 BILL JOHNSON (Amateur Radio) The story of the spacecraft that truly flies. JOHN GARNER (Short Wave Listening) DICK CARTWRIGHT (Servicing) APL: GOOD FOR THE BRAIN 22 A well tested concept is coming of age. EDITORIAL AND ADVERTISING VIDEO ACCESSORIES 46 OFFICES Add-ons to keep your machinery happy. Unit 6. 25 Overlea Boulevard, HOME CLIMATE CONTROL 49 Toronto. Ontario. M4H 1B1 Play with your environment for greater comfort. Telephone (416) 423-3262 CALCULATOR HANGMAN 64 Second Class Mail registration number 3955. ETI Softspot: A word game with digits. Return postage guaranteed. Post Officereturns toUnit6, 25 Overlea Boulevard,Toronto. Ontario. M4H 161. Published by Electronics Today International (Canada) Ltd. Printed by Livingstone Printing Ltd. NEWS &COLUMNS News Stand Distribution Gordon & NEWS DIGEST Gotch. Toronto. 4 AUDIO TODAY 9 Copyright: All material is subject to world-wide Noise about noise. Copyright protection. All reasonable careis taken to ensure the accuracy of the information. SERVICE NEWS 57 QRM .59 ALL ETI PCB PATTERNS ARE COPYRIGHT. Repeaters repeaters repeaters. . . NO COMPANY MAY SELL BOARDS TO OUR DESIGNS WITHOUT OUR PERMISSION. QSLS FOR SW LS 61 Shortwave World. INTERNATIONAL EDITIONS INTERS! L CMOS 5551 68 Electronics Today International Facelift for trusty timer chip. 25-27 Oxford St.. London W1R 1 RF, UK. Editor Halvor Moorshead. THE FUN OF ELECTRONICS 70 Electronics Today International, Ryrie House. 15 Boundary St., Rushcutters Bay. Sydney. Australia. Editor Coltyn Rivers. INFO & MISCELLANEOUS Electronica Top Internationaal, Postbus 260. Emmen, Holland. Canadian Projects No. 11 2 ETI Circuits 48 Editor Anton Kriegsman Contents 3 Classified Ads 71 ETI Binders Elrad, 8 ETI Project File 72 Kommanditgesellschaft, Bissendorfer Subscriptions Card&30 ETI Panel Transfers 73 Strasse 8, 3000 Hannover 61, Germany. Next Month's ETI 36 Reader Service Info 74 Editor Udo Wittig. Electronics Paperbacks .40,58,69 Advertisers' Index 74

ETI CANADA-MARCH 1979 3 NEWS DIGEST Opto-Coupler Motorola has introduced the industry's first optically -isolated ac linear opto coupler, the M005010. The new linearcouplerusesagallium arsenideinfraredemitting diode, optically -coupledto a bipolar monolithic amplifier.Itconverts an input current variation to an output voltage variation while providing a high degree of electrical isolation between input and output. Its use replaces a normal coupler, plus an operational amplifier and a discrete transistor from circuitry where isolated linear output is desired. The device can be biased to maintain a linear output of up to 4 volts peak -to - peak with a 12 volt supply voltage. The M005010 offers250 kHz(typ) bandwidth, 200 mV per mA gain, and low -impedance, emitter -follower output of less than 200 ohms. Applications include telephone couplers, peripheral equipment isolation,medicalelectronicsand audio uses. Available in the 6 -pin, DIP plastic package, the M005010 linear opto coupler is priced in the states at Cheap DVOM Maintainability is also excellent due to $3.25 each in 100 -upquantities. theuseofsocketsfor the major Deliveryis from factory stock and A new 31/2 digit pocket -sized digital components including the display and authorized Motorola distributors. multimeter has been introduced by The theextensiveuseofstandard Hickok Electrical Instrument components. The unit is covered by a 1 Company. The instrument, designated year warranty. Atari Computer LX 303, features auto -polarity, auto - The LX 303 measures DC volts from zeroandautomaticover -range 0.1 mV to 1000V with accuracy of+/ -0.5 The Atari 800 is a personal computer indication. The rugged, compact unit of reading +/-0.5 f.s.; resistance from with built-in modulator for TV display, fits easily in the palm of the hand, and 0.1 ohm to 20 megohms with accuracy standardkeyboard,cassetteordisk uses a half -inch LCD readout. The of +/-0.5% of reading +/-0.5 f.s. and DC memory, and 'memory cartridges' offer- reading rate is 3 reading per second. current from 0.01nA to 200mA with ing BASIC and other languages. A prin- Battery life is 200 hours minimum (300 accuracy of +/-1% of reading +/-0.5% ter (40 column) and other peripherals hours typical) from 9V alkaline battery. f.s.Operating temperature is 0to are under development.Start hinting Handy battery check capability is also 50 C. Size is 5-7/8" x 3-3/8" x 1-3/4" now in time for next Christmas - the provided. (147mm x 85mm x43mm) and weight is product is likely to appear in the shops Ruggedness is achieved in the LX 303 12 oz. (330 gm). in August or September. Price in the US by combination of light weight (12 oz. A full complement of accessories is will be around $1000. includingbattery), a high -impact also available including an AC adapter Atariwillalsolaunchtheir '400' thermo-plastic case, a glass -epoxy pc (115VAC and 220VAC versions)a computer around the same time - this board, and a snap -on cover which padded vinyl carrying case, a 10 A DC model will sell for about half the price protects the front panel (during storage current shunt, an X10 DCV probe of the 800 and is designed as a trans- or transit). The snap -on cover can also adaptor that protects the input to 10kV; itionalmachineto wean consumers be used to store the test lead set. All and a X100, 40kV DC probe. fromvideo games topersonal com- input jacks are recessed for operator $99.95 from H. Rogers, Box 310, 595 puters. safety. Mackenzie Ave., Units 1 & 2, Ajax, Ont., Reliability is assured bythe use of LSI L1 S 3C5. circuitry and laser trimmed thin film NS Tape Recorder IC resistor networks for low parts count. the excellent overload characteristics TI Bubble The LM1818 is a single -chiptape provide 1000 volt protection on all DC recorder (electronics only!) with built-in voltage ranges except the 200mV range TI's 92Kbit TIB0203 magnetic bubble record/playback switching. Just add the which is protected to 500V. All AC memory isavailable now on 4 to 6 mechanics, playback amplifier (there's ranges are protected by 600V. All ohms weeks delivery at a US price of $100 in a preamp on the IC) and simple switch- rangesareprotectedto120V. 100 quantities. es, sockets & battery.

4 ETI CANADA-MARCH 1979 Projection TVs Bell Tries Fibre Optics Sony of Canada's Industrial Division On December 12th last year field trial of has two new projection TVs. These 50" an integratedfibreopticsystem (KP-5000) and 72" (KP-7200) models designed by Bell Northern Research incorporatethree8"'High -bright' and furnished by Northern Telecom picture tubes forthe red, green and blue demonstratedthecapabdityof color beams. Two largeaperture simultaneous transmissionof 170mm lenses project the picture onto a telephony, data and video. .NIPlab. concave screen. The trialistakingplaceinthe Where the fibre meets the electronics Among the many standard features Yorkville area of Toronto and will at the Bell test centre. incorporated in this system are built-in continuefortwoyears. The In theoperationoftelephone VHF/UHF TV tuners with electronic experimental fibre optic customer -loop services over the fibre optic system, the channelselectors, built-instereo system consists of 1.2 kilometers of analog carrier converts the voice signal speakers and a remote control unit for graded -index fibre optic feeder, and up to a 76 k Hz amplitude modulated carrier power, channel selection and audio to 200 meters of graded -index fibre for transmission over fibre optics to the volume. optic buried -entrance service cable to subscriber's terminal. Ringing appears Sony Of Canada, Ltd., 88 Horner each of 35 subscriber participants and as a 20 Hz modulation of the 76 kHz Ave., Toronto, Ont. M8Z 4X8. to a Bell Canada test site. carrier. The carrier received from the The trial is unique in that it uses fibre distant end (subscriber)is 32 kHz Cesco Book optics in the loop -plant with actual amplitude modulated. Subscriber Catalogue subscribers' telephones, and in the use offhook condition is identified by the ofbi-directional opticalfibre C.O. by the presence of 32 kHz carrier. The Cesco Book Catalogue has just transmission. This condition causes the analog been published. Cesco believe that this Bell are optimistic about the future of carrier to seize the C.O. line circuit and is the first catalogue of its kind put out fibre optics. they suggest they will be returndial tone to the subscriber. byanelectronicsdistributorand implemented ecomically firstin the Rotary dial pulses interrupt the 32 kHz devoted to electronics books.Itis inter -office environment. By the 1980 to carrier from the subscriber causing the available free to anyone who wants it. 1982 period, the technological C.O. 'line circuit to be pulsed at the same The 32 -page catalogue contains 11 developments andthe system rate.Alternatively, in -band push- pages ofinfo on French -language economicswilljustifywidescale button signalling can be used. books, plus large listings of Sams and exploitationoffibrecablesin Eachindividualloopfacility is Tab publications. transmission systems of metropolitan designedtocarryone telephone Cesco Electronics Ltd., 4050 Jean areas. channel together with the capability of Talon St. W., Montreal, H4P 1W1. But it is in the introduction of fibre a centrally switched, one-way video optics in the loop system that the most channel from the central office to the dramatic effects can be expected. A subscriber - and the associated Row - Kepco Power Supply fibre optic telecommunication 'network speed data signalling channel from the Catalogue could integrate telephone, television subscriber to thecentral officeforvideo distribution, data and new broadband channel selection. The lattercapability A free 144 -page catalogue describes services in one medium for the mutual wil enable cable -TV or other vidio Kepco power supplies describes that benefitofthepublic and service services to be added to the system at a use switching techniques ferroreson- entrepreneurs such as CATV later date if this becomes desirable. ance, linear feedback. operators. Four subscriber loops willuse bi- The range includes programmable For the Yorkville Trial, Bell Canada is directional transmission on a single types, in both unipolar and bipolar primarily concerned with interaction of fibre to evaluate this mode of operation, designswithnew automatictest the new techniques: the fibre optic while the remaining subscriber loops equipment featured. Also featured are cable, splicing closures, electro-optics willbeunidirectionaltransmission new IEEE -488 GP-IB interfaces for the and the handling of the entire system in usinc two fibres. programmable power supplies. the outside plant environment. Three test lines will be used inthefirst The catalogue contains 32 pages of helpful application hints and design The optical system is largely off -the - phaseofthetrialtotestand tutorial. Receive your free copy of the shelf, using LEDS rather than laser demonstrate a variety of services such sources.Theopticalcomponents as: 1979 Kepco Power Supply Catalogue Basic individual telephone service bywriting:RadionicsLtd.,195 operate at 840 nanometers wavelength, which may not be optimum for loop- Conference -TV service Graveline St., Montreal, Quebec, H4T Remote video surveillance 1R6. plant; but sources and detectors for longer wavelength transmission were Simulated CATV service not readily available and must await Video retrieval service Philips Videodisk? later trials for evaluation. Library video retrieval service Video display and teleprinter data Rumourhas itthatthevideodisk At the customer premises, specially terminal on dataphone service. machine that was meant to be on the designed subscriber terminals contain Futurephasesofthetrialwill market in 1976 is due to hit the shops theopticalmultiplex,optical introduce a number of potential new about now. The 60 minutes a side mach- transmitterandreceiver,alarm serviceofferingsatthetestsite, inefromPhilips/Magnavoxwillcost systems, analog carrier and a video including videotex and similar something like $700 in the states. converter amplifier. interactive graphics systems.

ETI CANADA-MARCH 1979 5 More Scope for yourMoney

&Wit

Exclusive

0S255 $785* *Canadian price. Induces two P812 probes. Duty and federal sales tax included. FOB shipping point. Provincial taxes extra where applicable. Subject to change on parts without notice. and labour FEATURES AVAILABLE FROM STOCK For immediate availability from 15MHz, dual trace, stock visit the ACA Electronic Centre 2mV/cm sensitivity Here's an all new scope at nearest you in Toronto, Montreal, a new low price. The model 100ns/cm to 0.5 sec/cm Calgary and Vancouver. Shop in time base speeds person or by mail. Master Charge 0S255 is the first in a new family and Chargex-Visa accepted. of Gould/Advance scopes Variable sensitivity incorporating more features and sweep speed FREE CATALOG per dollar than previous scopes. ACA offers a Excellent overall trigger complete range With the 15 MHz, dual trace performance includes A.C., D.C. or T.V. trigger. of oscilloscopes. model 0S255 you get two PB12 Write or phone probes at no extra cost, sum and Algebraic sum for your free ELECTRONIC CENTRES difference capability, channel 2 and difference oscilloscope of channels catalog. inversion, and improved trigger 1 and 2 features. Plus the 0S255 is packaged X -Y display on a new in a new tubular improved 8 x 10 cm CRT Allan Crawford housing configura- Reliability, serviceability Associates Ltd. tion designed for and portability rugged field use Includes two PB12 TORONTO MONTREAL VANCOUVER (X1, X10) probes 416/678-1500 514/670-1212 604/294-1326 and ease OTTAWA CALGARY HALIFAX of servicing. 613/829-9651 403/230-1341 902/469-7865 NEWS DIGEST Engineers Wanted businessadministrationcraduates. Audio Cartridge Heads The recent Technical Service Council's The classes in arts and general science Record/playback headsdeveloped by a quarterly study of job vacancies for are so large that many graduates are British company are claimed to raise professionals reported increased likely to take positions at levels which the performance of broadcast cartridge openings for scientists and engineers, are below their expectations. Starting machines up to and above that of reel- reflecting vacancies in manufacturing, salaries for 1979 graduates vary with to-reelmachines. After small mining, construction and consulting both discipline and location, but are modifications to equipment, they have (but not governments and institutions). likely to be in the range of $13,700 for resolved frequencies in the range 40Hz Vacancies for experienced computer arts graduates to $16,700 fore ngineers. to 15k-lz at +/-1dB, against between programmers and systems analysts Graduates whose courses are in little +3.5dB and -2.5dB from other heads reached 202, the largest number ever demand are likely to receive lower and between +/-2.5dBfrom reel-to-reel reportedfora single occupational salaries if they do not secure a position machines. group.Most openings arefor by May. The two and threechannel heads (the experience people with three to five The Technical Service Council is a ext-a channelin each caseisfor years' experience. Opportunities for non-profitpersonnelccnsulting control) were designed to meet the managers ofdata processing service and placement firm run by requirementsoftheUnited States departments are limited. industry. It was set up in 1927tocombat National Association of Broadcasters. Experiencedsales engineers are the brain drain tothe United Sates. Asa Mechanically they are comparable with usually in short supply, even when the practical means of doing so, it operates other heads. economy is slack. The demand forsuch a coast -to -coast placement service for The standard range of fully plug- people has recently intensified, with accountants,engineers, scientists, compatibleheadshavespecial 171 openingsreported. Employers personnel managers, data-processing profiling and lamination -core to shield- unabletointerestprofessional staff,executives, technologists and car material matching that extends life engineers in sales have been hiring others. The serviceisfinanced by corsiderably beyond normal head life. technologists. industry and no charge is made to Magnetic Components Ltd., Penryn, Jobopportunitiesforthe1979 individuals. The TSC has offices in Cornwall, TRIO 8AR, UK. Tel: Penryn university graduating classes seem Montreal, Toronto, Winnipeg Calgary, (0326) 72267 Telex: 45377 best for engineers, commerce and Edmonton and Vancouver. New ARRL Handbook The 1979 AR R L Handbook is now out andsellingat a $10.75. New in this edition is a section microfile Tne BASIC -80 extensions provide on narrow -band voice modulation, plus access to the Intellec system disk files some rewrittten theory sections, and for 'ull sequential and random disk file some new- data. The section on semi- input/output. They include support for conductors is twice as big as previous the Intel single and double precision ones. Add to this a stack of construct- Intel BASIC -80 floating point standards and provide for ional projects, and everything else a ham integer and stringdata types with could ever wish for and you have 544 BASIC -80,a high level language and extensivestringmanipulation pagesofcleanfun.Availablefrom interpreter, hasbeen ar nounced capabilities. Language extensions ARRL dealers or The American Radio Intel'sM crocomputer Systems include direct read and write of the CPU Relay League, 225 Main, Newington, Division. BASIC -80 adds to the utility of input/output ports, direct memory read CT 06111, USA. Intel'sIntellec Microcomputer and write through PEEK and POKE Development Systems by providing a functions, a formatted print statement PLL Bugbook convenient, inexpensivefacilityfor with the PRINT USING function, and IF applicationsprogramming and BRS-7, ... THEN statements extended with an the Phase -Locked Loop problem so ving, as well as an aid for ELSE clause. Reference Book with Experiments is an microprocessor systems development. Other BASIC -80 extensions include introduction to the implementation of Standard ANS 78 BASIC features Boclean Operators and operation with Phase -locked loop integrated circuits. provided by BASIC -80 include: string matrices with up to 110 dimensions. To E& L Instruments has added this 6 x 9 and numeric constants, variables and assist in debugging, Intel BASIC -80 inch soft cover text to the Bugbook arrays; FOR ...TO ...STEP.. NEXT... alscincludesuserdirectederror ReferenceSeries.Itis written by . statements for loop execution; IF . trapping and handling functions plus a Howard M. Berlin and edited by C. THENstatementsforconditional program execution trace command. Titus, D. Larsen, P. Rony and J. Titus. execution; ON ...GOTO statements for BASIC -80 can be added to any of The 270pagescoverthe non - calculated branching; and GOSUB/ Intel's Intellec SeriesIIor MDS-800 mathematical principles of the phase- RETURN forsubroutinecalls and seriesmicrocomputer development locked loop, with a wide range of returns. Standard ANS 78 BASIC also systems with 48K bytes of RAM and at experiments. allowstheusertodefinesingle least one disk drive.Itis available The book is available from the States, statement functions.Itsbuilt-in immediatily on single or doubledensity priced at U.S. $8.95, E &L Instruments, scientific functions include: ABS, EXP, diskettes; order product code YIDS- Inc., 61FirstSt.,Derby, CT 06418, INT, LOG, RND, SGN, SQR, ATN, TAN, 320 The U.S. price is $750 fcr the U.S.A. COS, and SIN. diskettes and accompanying manuals.

ETI CANADA-MARCH 1979 7 NEWS DIGEST authorized distributors. Unit U.S. price 8185 Exorterm is$300. For additional information RAM Motorola Microsystems has introduced contact Motorola Microsystems, P.O. its new Exorterm 220 display terminal Box 20912, Phoenix, AZ 85036, or call The 8185 1Kx8 static RAM in an 18 -pin and console. This is a development Microsystems marketing at (602) 962- package was introduced today by Intel support system for the M6800 family of 2223. Corporation's Microcomputer microprocessors, including the Components Division. To permit this MC6800, MC68A00 and MC68B00. Printerm 879 large, 8 -bit, byte -oriented memory tofit A basic Exorterm 220 incorporates a in such a small package, the RAM CRT II Module, Debug II module two featuresaddress/datamultiplexing 16K RAM Modules,theResident which is directly compatible with the Relocatable Macro Assembler/Linking 8085A microprocessor series. Loader and the CRT Editor. The use of multiplexing is common In addition to use as a development for dynamic RAMs but uncommon for system, the terminal may be used as an statics. Static memories are normally asynchronous editing terminal through installedinsmaller systems where connection toa host computer (orother addingmultiplexedsignalswould external device) via the serial interface become a chore. However, the 8085A is (RS -232C or current loop), essentially designed to provide not just address, bypassing the isolated motherboard. but address and data multiplexing. This The U.S. price of the Exorterm 220 enables each device in the system to Bundled System with 32K RAM, CRT Here's a low -redundancypress save the eight pins that would be Editor, Macro Assembler and Linking announcement on this new printer: required for independent data lines. Loader,' on MDOS Diskette is $8600. High speed bi-directional printing, Same as above except 32K static RAM 120 cps at 75 lines per minute. 9 x 7 or 9 x 8080/8085 Bugbook costs $9200. 9 high density matrix, with up to 4 copies. 96 character ASCII character BugbookVIII,8080/8085 Software set(upper,lower, and triple wide Design with 190 Software Solutions is a CRT Editor expanded). Operator switch selectable detailedtreatmentofassembly Motorola Microsystems has 80 or 132 column format. RS232 and language programming for 8080 and announced a new Resident CRT Editor, parallel interface. 8085 basedcomputers. E & L the M6800 Editorm, which will allowthe Roll paper feed, combination pin Instruments has added this 6 x 9 inch M6800 Exorciser or Exorterm to create form and roll feed, or tractor feed. 2K paperback tothe Bugbook Series, and modify source programs. memory forfullpage CRT dump. written by Dr. Christopher A. Titus and The M6800 Editorm is available only Simplicity of design with only 3 sub edited by D. Larsen, P. Rony, and J. on MDOS diskette and requires an system moving parts for high reliability, Titus and C.Titus. 288 pages of Exorciser/Exortermwith 32K RAM all servo motor direct driven. Price elementary and advanced instructions capability. $1395.00 for standard model. are analyzed and discussed. The resident CRT editoris now Printer Terminals Corporation, P.O. The book is available from the U.S., availablefor ordering through Box 535, Ramona, CA 92065 priced at $9.00, from E & L Instruments, Motorola OEM salesofficesand (note: price is the U.S. price.) Inc. 61 First St. Derby, CT06418, U.S.A.

In response to many requests from our readers we have arranged for binders to be made so that you can keep ETI's first volumes together and protected from damage.The binders are covered in attractive leather -look black plastic and are designed to hold twelve issues. The ETI design is BINDERS printed in gold letters on the spine.

The binders cost $6.00 each, which includes postage and packaging. Do not sendcash - you can pay by cheque. Mastercharge, or Chargex Credit card orders must include your account number, the expiry date, and yoursignature. In all cases allow six weeks for delivery. Send your order to ETI Binders, Unit 6, 25 Overlea Blvd., Toronto, OntarioM4H 1B1. Don't forget to include your name and address. Ontario residents add 7% PST.

ETI CANADA-MARCH 1979 8 Audio Today

Developments in audio reviewed by Wally Parsons

ONE THING WHICH is often forgotten response in the range in which the noise level.Itis this basis which results in about noise is the variety of reactions to appears. Properly used, this system is each of us reacting to noise differently, it. Different people find different kinds more useful than many people believe. and it is this kind of mechanism which of noise more irritating, and the level The total noise energy increases, per results in each of us hearing a little seems to depend very much on the kind octave, as frequency goes up. Thus, in a differently from each other. of noise, and the individual's particular system with a bandwidth of 20 kHz, up sensitivity to a given kind. For my part, I to half the total noise energy may be in FILTER SHAPE can live with what many people would the last octave. Therefore, reducing A low pass (or high cut) filter has two consider to be remarkably high 60 Hz response above 10 kHz will produce a characteristicsofinterestforour hum levels, probably as a result of considerable reduction in noise. "But," present purposes: cut-off frequency, having started in audio with vacuum yousay, "whataboutthehigh Fo, and slope, or rate or attenuation. For tubes. However, 120 Hz power supply harmonics?". What harmonics. Even a given nominal cut-off frequency, the hum is an entirely different matter, as is for persons with response high enough sharper the roll -off, the more noise the presence of any spikeyness in the to hear the noise, we only lose the last energy is attenuated, and the less hum waveform. Even today I frequently octave. In terms of music, very little programme energy lost. In other words play many of my early 78's unfiltered harmonic content is up this high, and the sharper the cut-off, the wider the and somehow the surface noise doesn't even fewer programme sources bandwidth which can be retained for a bother me, yet many of the Columbia actually contain it. Therefore, we are givennoisereduction.Noisy Long plays of the late 50's and early 60's cutting off something which we rarely recordings especially, benefit from this sound intolerable. The generally high ever had anyway. Even FM radio cuts off treatment; all too often, the noise is the noise level experienced on AM radio is at 15 kHz anyway, whether there is result of wear, and the very high no problem, yet let even a little noise anythingthereor not. I'm not frequencies, if they were ever there at creeping in on FM and I start checking suggesting :hat this last octave is of no all, have actually been gouged away, antennalines and signalstrength. importance, but that there is little point leaving noise anddistortion in their Many people will tolerate coughing, in trying to reproducesomething which place. So you trade off a little bandwidth talking and all kinds of noises at a isn't there, or is buried in noise. which is not useable anyway, fora large concert, yet let one I ittletick appear on a reduction in distortion. recording and they write nasty letters tomanufacturers andjournalists BENEFITS HOW TO complaining about defective But look at what isgained bythis bit of Mostcommercialreceiversand pressings. surgery.First,of course, we've cut amplifiers have a switch labeled "High The methods ofeliminating the down the noise level tremendously. In Cut", "Scratch", or something similar. I different kinds of noise are about as so doing the masking effect of noise has have not seen many which did anything varied as the kinds of noise and the been reduced for the octaves below other than clutter up panel space. variety of reactions to them. Recently cutoff. Noise not only masks signals Usuallytheygiveaslopeof6 we examinednoiseasitaffects within the passband covered by the dBiOctave, which is pretty hopeless, dynamic range, and looked at systems particularportionofthenoise and could easily be duplicated with the for extending the range itself. This spectrum, under consideration, but treble control. The best choice is either month we'll have a go from the opposite also has some masking effect on a 2nd or 3rd order Butterworth filter, direction. signals removed from that region. The which gives a flat response to the cut- brain perceives the noise signal sent by UNCOMPLEMENTARY SYSTEMS off point thenattenuate at 12 dB/octave the ears, compares it with the signals or 18 dB/octave respectively. Active The simplest, and the oldest, system which can be distinguished then tries filter versions are shown in Fig. 1 and of reducing noise is to roll off system to ignore everything below a particular Fig. 2.

ETI CANADA-MARCH 1979 9 Fig. 1. Inverting second order Butterworth Fig.2. Non -inverting second order Butter- filter configuration. worth filter.

Each is a 2nd order filter, but Fig. 1 is noise does not increase with signal, so large change in source to drain current, an inverting type which Fig. 2 is non - at high levels the signal to noise ratio is but below the knee it operates as a inverting. Adding an additional RC actually improved, resulting in the need variable resistor.If a FET channel is section to the input produces a 3rd for less filtering. At high signal levels, substituted for any of the resistors in order filter. For design details, see ETI the signal may easily mask the noise, so Figs. 1, 2 or 3, the turnover frequency circuits, No. 1, ortheNational it is quite practical to raise the cut-off can be varied by varying the gate Semiconductor Linear IC handbook. frequency. The obvious way to do this is voltage.Ifthiscontrolvoltageis Fig. 3 is also a 2nd order filter, but this to change either the resistance values obtained by rectifying the signal, then description is really only applicable to orthereactancevaluesorboth. the signal controls the cut-off point. the ultimate slope of 12 dB/octave. Obviously, it's not very practical to twist This is shown in Fig. 5. Figure 6 showsa Although simpler and cheaper to build a knob and vary them manually, if only variable slope system which appeared it suffers from the disadvantage of a less because dynamic peaks tend to come in ETI December 1978 as a noise limiter sharp turnover point. If both sections on too suddenly for the hand to track project. In this circuit, Q1 acts as a are identical, the design turnover point them. Some other method must be buffer, D1 and D2 form a rectifier, and is actually 6 dB down rather than 3 dB, provided such that the signal itself Q2 acts as a signal controlled variable and so sections should be designed as provides the control. resistor in series with C4. Note that Fig. for a corner frequency 1.4 timesthe one 5 requires that Q1 must have reverse desired. FETS PROVIDE VCRS bias at no signal level, and the bias is FOR VCFS reduced as signal is increased. This can be accomplished by adjusting the off- Fig.3. Second order passive filter network. Figure 4 shows a J-FET connected as set of IC1. Fig. 6 is simpler in that under a variable resistance, along with a set of no -signal conditions no bias is characteristic curves. When operated produced and Q2 displays minimum at a supply voltage above the knee, the resistance. It has the disadvantage of device acts as an amplifier in that a upsettingfrequency balanceat small change in gate voltage causes a intermediate levels. 0 T T 0

Fig. 4. Characteristics of a JFET. RIGIDITY Such filters are generally useful for moderatereductionoftapehiss, surface background noise, and the like, where a cut-off of 7 kHz or higher is suitable.However, where noise problems are more acute, such filters would require a cut-off as low as 3 kHz to be effective. When programme level isfairlylow andwithlittlehigh CONTROL frequencycontent,nosignificant VOLTAGE signal degradation occurs. But music programmeisnot constantinits characteristics, and if portions of the programme contain significant high Drain - Source Voltage VD, frequency content, there is a severe loss of brightness. Generally, average FET CHARACTERISTICS

10 ETI CANADA-MARCH 1979 Audio Today

One disadvantage of all such types Fig. 5. JFET used to control filter cut-off point. lies in the fact that clicks and pops can trigger expansion (and "expansion" is really the principle involved). This is OUT overcome by an RC network at the output of the rectifier, which controls the attack time. If the time constant is too long, though it will not respond to dynamic peaks. Clicks and pops can be removed by splitting the signal into two channels, one of which is a normal feed - through channel and the other, called a side -chain, is identical except that it includes a time delay line. A detector senses the very fast -rising click pulse and operates an electronic switch 0-1 causing the output to switch to the FROM delay line. The click portion is thus BUFFER removed, and replaced by a portion of the programme signal a few milliseconds prior to the offending noise. When that clickis detected, output is then switched back to the main channel. The use of such a device Fig. 6. In this circuit the JFET controls the slope of the filter. prior to any dynamic noise filtering will allow the filter to be set for a fast attack time. 0 Readers interested in a really sophisticated device which combines bothfunctions, although theclick suppressor operates somewhat differently, are referred to the Feb 1971 issue of the Journal of the Audio Engineering Society, and the description of a "Dynamic Noise Filter" INPUT OUTPUT by Richard S. Burwen. Fascinating. Audio Today

If you want to express your views or report on news write to Audio Letters Today, ETI Magazine, Unit Six, 25 Overlea Blvd, Toronto. Ont. M4H 1 B1.

ETI TUNER OFFER I have purchased one of the tuners Full Wave, 2 diode mode and a 500 uF advertisedinyour December 1978 capacitor. Unfortunately I did not know that you issue. It works very well both on AM and Thank you for your assistance in would be offering a tuner identical to FM. above. one I recently purchased (for a higher I should like to ask how the FM L.M., Guelph, Ont. price, of course). Anyway, the unit Beacon light and the mono/stereo works fine but I have one problem. switch are connected into the circuit. Do you also drive without seat -belts The output of the tuner is fairly low Any assistance regarding the above inGuelph? No specificationsare and though that doesn't matter with a mentionedwould be greatly supplied with this unit as to supply high powered amp, it does with the 5 appreciated. requirements, and as the parts are

Watt amp that I also constructed. Do For your information the FIM portion made in Japan for this Canadian tuner you have any suggestion fora pre -amp draws 40 mA DC with a +12VDC supply thesecharacteristicsarenot to boost the signal. and the AM section about 10 mA. The immediatelyapparent.Althoughit P.S. The 5 Watt amp works really well. unit works well without a regulated works well without a regulated supply, a P.B., Toronto supply.I used a Hammond 166D20 in little study will show thatthedecoder IC

ETI CANADA-MARCH 1979 Interested in LEDs? See page 69. 11 is similar to type uA732. This device has Fig. 1.(letters) Wally's first hypothetical design. Fig. 2. (letters) Wally's second design. a maximum rating of 15 V. Your supply is capable of delivering a peak output underzero, or verylightload conditions, of 14 V with a line voltage of 117 V. This allows very little leeway for high line voltages. And if you switch B plus when going from AM to FM you will be applying very close to open circuit voltage to the FM section. Probably componenttoleranceswillbe adequate, but for a few dollars more, why not do the job right. I'm running a unit on a 12 V regulated bench supply. Operation is stable, with no drift in characteristics. Total current draw is 45 mA,10% lower than yourfigure. Moreover, a regulated supply increases immunity to line borne noise and allows alignment to be tweaked for maximum sensitivity, signal-to-noise ratio, and minimum distortion. The power supply I plan on using will be built around a Hammond type 226F is in use. This is especially practical if you. Anyway, if you build the circuit I and a 78L12 monolithic regulator. It will you switch B plus. suggested, don't try to reduce the gain include a buffer amp similar to either A multi -turn dial assembly makes a byincreasing R3or R2, orby Fig. 1 orFig.2 (thishasn't been great tuning dial. A digital meter would decreasing R1; the LM387A is only finalized). Fig.1 provides 20 dB gain also be nice, but I haven't yet figured a compensated for again of 10 or more. If with high slow rate and low output way to connect one. Finding a circuit this is excessive use a volume control of impedancewithshortcircuit pointis no problem but finding a about 100I in front of C1 (DON'T protection, while Fig. 2 will provide suitable point which is also accessible connect it to pin 1 or 8 of the IC or you'll about 14 dB gain and is suitable where is. Anyone with ideas in this area is shut the device down by removing bias AM and FM functions are selected by urged to write. from the input stage). switching B plus. Thislatter The FM Beacon should be connected This tuner will connect directly to a 75 arrangement allows one meter to be between the indicated terminal and B Ohm TV cable with no problems. used for signal strength measurement plus, with a series resistor suitable to for both AM and FM without ambiguous limit current draw to 100 mA or less. An AUDIO FUNDAMENTALS readings (the metering signal from LED wouldbeappropriate. The I have been reading your magazine each section is passively mixed on the stereo/mono switch should connect since its inception (before, actually) board). terminal 1 togroundformono and I have been impressed with the While on the subject of metering, the operation. This turns off the 19 kHz quality of articles and the wealth of meter supplied should be installed with amplifier thus also blanking the stereo about 50 k resistance in series if it is beacon. information that is contained in your magazine. I used for signal metering. If you wish to Returning tothepreamp/buffer would like to see a little use one meter for AM and FM, it can be question, the output of this tuner is more information on hardware for ambitious projects, i.e. cabinets, switchedtoterminal P20 for AM about that of a 34dB phono pre -amp transformers, metering, where it will measure AGC with a lowoutput pickup. A 5W amplifier etc.These arevery voltage.Itwillalso deflectinthe will not deliver more power with a pre - difficult to obtain in my area.I would oppositedirectionfrom FM thus amp but will give more audio sensitivity. also like to see some good speaker automatically indicating which mode Don't let the volume control setting fool designs, specifically subwoofers, of all types. The Wally Parsons articles just whet the appetite. Also how about some high power amplifiers (over 200 Watts) Jensen TriaxiaF 3 -way Speakers or high quality low power amps (but greater than 30 Watts). Still, these are Quite simply. the most advanced car stereo minor nigglings with a good product. speakerever. Where does one find information on For the best sound ever in your car. The first car building speaker systems? I already stereo speaker with a woofer, a tweeter and a have the latest Philips edition but the midrange authors do not give general design Identical in principle to the best home stereo principles. speakers. Jensen s midrange picks up a whole range of tones lost to any other car speaker. How can hum and noise be reduced in a phono preamp? I have tried almost Write today for Free catalogues and the name of your everything (my preampisself-builtwith nearest Jensen Dealer - an LM387 chip)butlisteningon len finkler ltd headphones is still excruciating. 25 Toro Road, Downsview, Ontario M3J 2A6 Thanks for your time. Telephone (416) 630-9103 Telex 065-24010 A.C., Windsor, Ont.

12 ETI CANADA-MARCH 1979 Audio Today

I gather you like us. Idon't quite know can be minimized by using good quality how to take the "whet the appetite" part, components. This means metal film Kits for but you must realize that ETI only resistors and metallized mylar comes out once a month, and "Audio capacitors or thelike,not carbon ETI Projects Today" is only a year old. And despite composition resisitors and ceramic the number of readers able to sink their disccapacitors, and definitelynot Now Available teeth into some real meat, there are electrolytics in the signal or feedback ETI Graphic Equalizer many others who require a greater paths (except for C2 in Fig. 1 which may $166.00 (power supply not incl.) emphasis on basics. be a tantalum type when used as a Finished cabinet $13.95 extra. A case in point is your letter with its phono preamp). This device is mainly ETI Project No. 134 three problems. Knowing how much suitableforusewithpickupsof True RMS Voltmeter electronicsisinvolvedinthe moderate impedances and output, $89.95 automotive industry,I find it hard to such as most moving magnet types. ETI Project No. 450 believe that parts would be difficult to Moving coil types will not give sufficient Bucket Brigade find in a city like Windsor. Try the outputorofferoptimumsource Audio Delay Line Yellow Pages for starters. Ask a TV impedance unless a transformer is $48.50 repair shop. And acquire distributor's used. ETI Project No. 486 catalogues. Last year ETI published a How's that for solid stuff? Frequency Shifter comprehensive compendium of $69.95 catalogues, and we'll probably update it ETI Project No. 585 sometime this year. Some of these NOISE REDUCTION Ultrasonic Switch catalogues, such as Electro Sonic's, $29.95 cost money, but are worth every penny. ETI CCD Phaser Compared with readers in some of the I am considering buying a noise $79.95 small towns who write to us, you and I reduction system (not Dolby) for my Hi- Cheque, Money OrderorMastercharge both have it easy, (l have to drive over 50 fi. I have seen various sytems on the Include card expiry date and numoer miles for a reasonable selection at market which say they eliminate noise Ontario residents please add 7% sales tax reasonable prices). from tape, phono and FM sourceswhile DO NOT SEND CASH I would recommend to you "How to expanding dynamic range. Are these Allow 3 weeks for delivery Build Speaker Enclosures" by Alexis sytems as good as they sound, and does DOMINION RADIO & Badmaieff and Don Davis, published by your project section plan to publish ELECTRONICS Howard W. Sams, catalogue number plans for the construction of this type of 535 Yonge St. Toronto 20520, available at most dealers. It's an system? Ontario M4Y 1Y5 excellent and detailed book suitable for beginners and hobbyists with some G.V., Toronto experience.A more advanced publication recently came out from WHY GET YOUR ***** TAB books, number 1064, "How to All systems are as good as they sound IN AN UPROAR? Design, Build, and Test Loudspeakers" (oops, there we go again with the by David Weems. semantic humour; Second City, move over). Actually, the choice of system is CERESIST If your pre -amp is self -built, perhaps more dependent on application, since you should ask it to write me a letter (a they all do pretty much what they claim dry transfers come inpads, little semantic humour, there). Anyway, to do. Dolby "B" is -the most useful lines,ICpatterns, etc. Just you make no mention of noise when choice in a complementary system rub down directly onthe using loudpseakers. If you connect a since it is standardized and allows tapes PCB to make up your circuit sensitive headset directly across the and broadcaststobe exchanged. - and etch! Fast and easy to speaker terminals you will certainly However,for cleaning up existing hear a lot of noise, from every stage in signals,nothingwilltouch an use,CERESIST givespro- the amplifier.It should be padded Autocorrelator for maximum cleaning fessionalresults every time. down, not only to reduce noise but to with minimalsignaldegradation. protect the phones and your ears (I Dynamic range expansion can be At your dealers- or write to wouldpersonallyliketoseeall accomplished with one of the DBX CERES, 53 BURNETT AVE. headphones self-destructat sound products, or the Compander which WI LLOVVDALE, ONT. M2N levels dangerous tohearing).The appeared in ETI in January 1978 (back 1V2. LM387 is quiet, and the LM387/A even issues are still available as of January quieter. But to minimize 60 Hz hum you 1979). None of them should substitute SPECIAL OFFER- Save mustobservegoodconstruction for good design. The best cure for pre - your CERESIST sleeve head- practice:don't mount a power amp noise is a quiet pre -amp, and the ers. transformer too close to the devices, best cure for tape noise is quiet tape and We willsend you 1 avoid ground loops 'in both the internal recording electronics. Only when these free sheet for every 5 headers and external wiring, watch out for cold noise sources have been reduced to a you send in.Enclose stamp solder joints.120 Hz hum can be minimum should you use a noise and specify desired pattern. minimized by good filteringin the reduction system. power supply, although the on -chip By the way, did you ever build the 50 n oommo regulatorminimizesthisproblem Watt amplifier (Audio Today Letters, ceresist provided the supply voltage is above ETI May 1978)? If so, how about writing o osm000 about 12 V.Aperiodic noise, i.e. hiss, and telling us how it worked out for you.

ETI CANADA-MARCH 1979 13 The Rockwell

THE FIRST FREE -FLIGHT test of the Space Shuttle, and the solid rocket boosters used to provide the enormous watched by 60,000 people marked the commencement thrust at takeoff are also reusable. In fact, a Space Shuttle of the final phase of months of testing at Edwards Air can be launched as quickly as 160 hours after landing from Force Base in the Mojave Desert of Southern California. the previous mission, although a two-week ground turn- At the end of January 1977 the Shuttle was moved from around is the goal in actual use. its assembly facility at Palmdale, along 58 km of specially

widened roads to Edwards AFB, for the first Approach UP UP AND.. . and Landing Test (ALT). The Shuttle is launched vertically, attached to an external The Space Shuttle is the first of a new breed of space- tank which contains the ascent fuel burnt by the Orbiter's craft which is designed to be reused. Previously, the tech- main engines, and two solid rocket boosters. At lift-off nology available meant that each spacecraft could be used all the engines fire in parallel, the SRB's each generating only once, but for any long-term program of space research 11,800,000 Newtons of thrust and the three Orbiter thisisextremely wasteful. Everything was built to the engines each generating 2,100,000 N. The two SRB's are highest standards and then used only once. The Space jettisoned once they burn out and are recovered after a Shuttle changes this. The Space Shuttle Orbiter vehicle is parachute descent. The external tank is jettisoned before designed to land intact in the same manner as an aircraft, the Orbiter attains orbit.

14 ETI CANADA-MARCH 1979 Space Shuttle

The Space Shuttle has had a relatively low profi'e after the exciting Apollo missions. Here's a look at what it's been up to.

The orbital manoeuvring system is used to make any launch payloads into orb[it,it can also retrieve and return adjustments to the orbit or any manoeuvres that may be them, and service or refurbish satellitesinspace. The required during the mission. The jets for this system are versatilityof the Shuttle's cargo opens up whole new mounted near the nose and in pods on the upper rear of areas, i.e. space manufacturing. the fuselage. These jets can pitch, roll or yaw the Orbiter. The Orbiter is designed to carry a crew of seven (early missions call for four), including scientific and technical DOWN personnel and a payload up to 18 m long and 5 m in Upon completion of the various mission duties, the crew diameter. Because of the low g forces at launch, only 3g will prepare the Orbiter for re-entry - this is when the and less than 1.5g on re-entry, space flight is no longer Space Shuttle really flies. The Orbiter, since it moves in limitedtointensivelyphysicallytrainedastronauts - the two media of air and vacuum, has two separate manoeu- now experienced scientists and technicians can have access vringsystems. One isthe orbital manoeuvring system to zero g, vacuum conditions. referred to above, and the other is a set of aerodynamic Payloads up to 29,500 kg can be placed into orbit. controlsurfacesthatactinmuch the same way as These can range from smallsatellites to fully equpped conventonal aircraft. scientific laboratories, and not only can the Space Shuttle There are seven aerodynamic control surfaces on the

ETI CANADA-MARCH 1979 15 rudder/air brakes

orbital positioningsystems main shuttle -orbiter engines -used only during lift-off

gimbal mounted rocket motors external (liquid oxygen)fuel tank for orbiter engines aircraft would respond - at subsonic speeds, at least. Above Mach 1.5 things go haywire - the result is like trying to ride a bicycle with your hands crossed, and only with considerable training can the pilot avoid making involuntary, incorrect movements of the RHC stick. In the AUTO mode, the FCS takes inputs from star sensors, inertial measurements units, rate gyros. separation accelerometers, and air data sensors, and compares this motors with the desired trajectory, automatically making cor- rections to keep on the path. In fact, the Orbiter can land generates control signals to implement the pilot's itself from orbit completely automatically, with the only commands. In this mode the FCS automatically takes pilot intervention required being landing gear extension account of the reverse effects produced by the aerody- and operating the brakes on the runway! namic surfaces at high airspeeds. In the CSS mode, the Flight Control System interprets between the pilot and the control surfaces. The pilot uses RE-ENTRY the Rotational Hand Controller and pedals, but the FCS The Orbiter starts re-entry at a high angle of attack, accepts these inputs as rate commands in pitch, roll or around 30 to 40 degrees, so that the bottom of the wing yaw - in other words, the way the pilot wants the and fuselage are exposed to the airstream. The under Orbiter to move. These commands are compared with surface is covered with a high -temperature structure of inputs from the rate gyros and accelerometers, and reinforced carbon -carbon on the leading edges and

16 ETI CANADA-MARCH 1979 The Rockwell Space Shuttle

reinforced carbon edge go and it responds in the correct way. The angle of attack must be carefully controlled to avoid overheating problems during the descent. To accomplish this, the Shuttle banks at up to 80 degrees, and so flies on a curved path. This would take the Shuttle away from its target and so, several times during the re-entry, the bank angle is reversed, and the vehicle starts turning back towards its target. This manoeuvre is complicated by the fact that, because of the high angle of attack, the rudder is virtually in a vacuum, and so these turns are executed by rolling the Shuttle. payload doors APPROACH Finally the Orbiter is down to a speed of Mach 1.5, and' begins to fly like a conventional aircraft.It is now at a height of 21,000 m and about 50 km from its landing field. From now on, things are straightforward as the pilot closes in using conventional electronic navigation equipment like TACAN and Microwave Scanning Beam Landing System. As he turns to the final flitepath, the crew module pilot will use the speedbrake on the tail to lose both speed and height. During this phase of the landing, the

The complete sys- tem. The only non - positioning motors reusable section is the fuel tank for theOrbiter en- gines. This drawingshows clearly thedif- ferent types of silicia heat resistant tiles thermal protection adopted on dif- ferent parts of the Orbiter.

reinforced carbon leading edges

parachutes packed in nose

speedbrake is normally open at 450. If the Orbiteris high, the pilot will open the speedbrake andsteepen his descent;if low, he will closeit and fly a shallower glidepath. The Orbiter makes final approach at 540 km /hr and solid fuel rocket booster at an angle as steep as 24'. At 600 m, the pilot starts to pull up, or 'flare', and at 300 m, the landinggear is dropped. The vehicle touches down at 350 km / hr;at this point it is losing 9 km / hr of speedevery second and stalls at 280 km / hr, which is why the landing is special silica tiles over most of the other surfacesto at such maintain the airframe within acceptable temperature high speed. limits. The Approach and Landing Testwere designed to Unfortunately, because of the high angle of attack, check out the performance of the Shuttle during this phase of the mission. They were also designed moving the RHC to the left in the DI R modecauses the to check Orbiter to roll to the right. This is because the right the performance of that now -famous 747 /Space elevon is deflected downward, but this Shuttle combination which will continueto fly, de- causes drag, and livering Orbiters to the launch site from the production turns the vehicle to the right. This increases the lifton the left wing, so itlifts, causing the right roll. In the line and landing sites. Control Stick Steering mode, though, this problem is FIRST FLIGHTS taken care of by the Flight Control System, and the pilot The first flight of the Space Shuttle took placeon 1 2th simply moves the stick the way he wants the vehicleto August last year. At 8 am,the 747 Shuttle Carrier ETI CANADA-MARCH 1979 How about a subscription? See the card facingpage 3. 17 LAUNCH SEPARATION OF SOLID -ROCKET BOOSTERS SEPARATION OF EXTERNAL TANK ORBIT INSERTION AND CIRCULARIZATION HEIGHT: 46 kilometers HEIGHT: 185 kilometers (28 miles) (115 miles, typical) VELOCITY: 5008 km/hr VELOCITY: 28,300 km/hr (3112 mph) (17.600 mph)

6'

The primary mission of the space shuttle is to deliver payloads to earth orbit. In a sense, it will be the workhorse of space exploration for years to come. Satellites will be placed in space and recovered by the shuttle. Orbital space research will be conducted aboard the shuttle. Construction crews building huge platforms in space will operate from this unusual orbital craft. Astronomers will greatly expand their knowledge of the heavens with telescopes borne aloft by the shuttle. In time, the shuttle may be flying earthmen to space factories and even space cities.

18 ETI CANADA-MARCH 1979 The Rockwell Space Shuttle

*is

C1

ORBITAL OPERATIONS ATMOSPHERIC ENTRY LANDING SERVICING FOR RELAUNCH HEIGHT 161 966 kilometers HEIGHT 122 Mometer, CROSSRANGE kilometers (100-600 miles) (76 miles) (11250 rr iles) DURATION 7 30 cloys VELOCITY 26.765 krni-Ir (from entry path) (16.633 mpn` VELOCITY, 335 km/ht (208 mph)

SHUTTLE CHARACTERISTICS (values ore approximate) LENGTH SYSTEM: 56.1 meters (184 feet) ORBITER: 37.1 meters (122 feet) HEIGHT SYSTEM: 23.1 meters (76 feet) ORBITER: 17.4 meters (57 feet) WINGSPAN ORBITER: 23.8 meters (78 feet) WEIGHT GROSS LIFT-OFF: BOEING 737 SHUTTLE ORBITER DOUGLAS DC 9 1.99 million kilograms (4.4 million pounds) ORBITER LANDING: 84.8 thousand kilograms (187 thousand pounds) Orbiter. Four of these are on the rear of the wings and are. THRUST called 'elevons' - they combine the effects of elevators SOUD-ROCKET BOOSTERS (2): 11.6 million newtons (26 million pounds) and ailerons. The fiftn surface is at the bottom rear of the of thrust each fuselage between the wings, and assists the elevons in ORBITER MAIN ENGINES (3): controlling the pitch of the craft.It also protects the 2.1 million newtons (470 thousand pounds) rocket engine nozzles from buffeting in the airstream of thrust each during re-entry. The two remaining panels are on the CARGO DAY DIMENSIONS: rear of the vertical tail and can be used as a rudder or 18.3 meters (60 feet) long, 4.6 meters (15 feet) spread apart to form a 'speedbrake' by increasing the in diameter drag. This is used to limit the airspeed during landing. ACCOMMODATIONS: Unmanned spacecraft to fully equipped At low speeds these surfaces act in a conventional scientific laboratories manner. However, at supersonic speeds above Mach 1.5, the effect of some of the control surfaces is FLIGHTS MODES reversed, or not the expected one, which makes flying in The Flight Control System (FCS) can be operated in three a conventional manner impossible! To get round this modes: Direct (DIR), Control Stick Steering (CSS) and problem, the Space Shuttle, unlike most aircraft, which AUTO. The mode can be selected separately for pitch, use mechanical or hydraulic links between pilot and roll /yaw, speedbrake and body flap controls. controls, uses a digital 'fly -by -wire' Flight Control In DIR mode, the pilot grips a small stick called the System. This is based on three on -board IBM System /4 Rotational Hand Controller and ordinary pedals. Move- Pi AP -101 computers which monitor their own operation ments of these inputs to the FCS produce movements of to provide a measure of fail-safe redundancy. the control surfaces in the same way as a conventional ETI CANADA-MARCH 1979 19 Space Shuttle Orbiter 101 rides "piggyback" atop NASA's 747 Carrier Aircraft in the first seies of captive approach and landing tests conducted at NASA's Dryden Flight Research Center at Edwards Air Force Bass in Californ a. With the Orbiter unmanned and its systems inactive, the highly successful first tests verified the safe operation of the combined vehicle configuration, Photo was taken at about 16,000 ft. above the California desert.

Space Shuttle can deliver both the materials and the machinery required to build large space st-uctures, such as this de- monstration satellite solar pcwer station. After being fabricated and assembled in low earth orbit, a power station would be transferred to its per- manent place in geosynchro- nous orbit (about 22,000 miles out in space). There it would beam a continuous stream of microwave energy to earth receivers, which would convert the energy to electricity. When cornpleied the station would be 1000 feet square and 25 feet thick.

The Shuttle orbiter cargo bay - which is larger (60 by 15 feet) than most freight cars - will accommodate a great variety of payload combinations. Payloads can be installed or removed while the orbiter is either horizontal or in the vertical position on the launch pad, as shown here, which greatly enhances operational flexibility. The payload "changeout" room is located in the white structure on the left.

20 ETI CANADA --MARCH 1979 The Rockwell Space Shuttle

Aircraft with its piggyback Orbiter took off on time - the A key Shuttle payload is Spacellab, center, a multipurpose only problem had been a fault in one of the AP101 laboratory that willl enable scientists to conduct experiments in the gravity -free environment of space. The lab is being produced computers, but that unit was quickly replaced. by the European Space Agency (ESA), a consortium off European nations, in cooperation with the National Aeronautics and Space At 8.47 the pair were at 8,539 m, and the Boeing Administration. started a 7` dive. At a speed of 280 kts, and a height of 7.346 m, the Boeing pilot informed the Shuttle crew that they were ready for separation. The crew, Haise and Fullerton, fired the separation bolts and lifted away, rolling to the left while the 747 dropped to the right. Following a pair of right and left rolls to put some distance between the two craft, Haise tried a practice flare and some banking manoeuvres. This gave the computers at Johnson Space Centre the opportunity to calculate any deviation from the predicted lift /drag ratios, information which would allow a more accurate landing. In fact, the JSC ground controllers muffed it by assuming that the Orbiter was in level flight, whereas it was actually climbing, so they concluded that the lift/drag ratio was lower than predicted. Haise could not open the speedbrake beyond 45°; this was a mission constraint to avoid steep glideslope angles. Performing a flare at 270m, Haise touched down 600m beyond the expected touch down point at a speed just over 360 km /hr. The overshoot was no problem, as runway 17 at Edwards AFB is 11 km long, but with the wheels on the ground, Haise opened the speedbrake to 90° and the nose wheel came down. The flight had lasted just 5 min 23 sec. The first three flights were made with a streamlined tail fairing covering the dummy rocket engines at the tail. The fourth flight, on 1 2th October, was made with the fairing removed, giving a slightly reduced lift /drag ratio.Otherwise, the vechicle did not behave significantly differently.

NEXT COMES NOTHING With all the approach and landing tests completed, the Shuttle programme moves into its next phase which takes it into space. In the middle of 1979 the Orbiter will be lifted from Cape Kennedy for its first real flight. At present the projected date is sometime in June, but this may well change. Rockwell are already selling space in the cargo bays - and doing very well too. One of the first payloads will be the Euro Space Lab, which will use the Orbiter's ability to stay put in space for up to a month or more. Cargos are being accepted from commercial firms too - soif you fancy sending a package into space this is your chance. Move quickly though because space in space(!) is hard to get and bookings stretch out a few years into the future.

HOPEFUL SIGN Of course the Shuttle gives us the capability to build space stations at last, with all that implies - solar power, weather control, observatories and star -ships. It may be a long time before Man does reach for the stars, but at least we've taken the first step.

Our thanks to Rockwell International - Space Division - for their assistance in the preparation of this article.

ETI CANADA-MARCH 1979 21 APL: Good For The Brain

A Programming Language has been around for many years, yet it is fast becoming THE new language. This exciting development in small computing systems is something that we think will be good for all of us.

IT HAS BEEN observed that not only fanatical supporters,itisvery useful 'that by giving alot of the most used does a language (English, French etc!) to know something about the language functions single symbol names (instead provide a means of expressing thoughts, itself. of just + - x and ÷ ) the user can not it also tends to limit thoughts, to those APL having originally evolved from only more easily write his ideas down, expressible in the language whether to Iverson Notation, itis most helpful to but evenlearn to think on a higher others, or to one's self.Just as a road startwiththosefeatures which are level. A good example of thisisa provides apath for transportation,if actually part of the notation. sorting operation, for example putting you get used to travelling by car you IVERSON NOTATION alistof names in alphabetical order. kind of have to stick to the road, and Iverson Notation gives you the concepts The first step to getting a grasp on thesurroundingterrainremainsun- of how to think of the list of names, Iverson Notation is to be familiar with discovered. a few 'buzz -concepts' essential to the and then allows you to write down, Soitiswith computer languages. usingjust acoupleof symbols, the topic. IversonNotationwas developedfor method used to do it.Example later. Essentially IversonNotation is a humans to use, to advance their ability mathematical notation which permits DATA TYPE to think andsolveproblems. APL expressions to be written in very com- Ina mathematical expression, one grew from this, andisprobably the only language to pick up an already pact and condensed forms. The idea is may have a variety of different types developednotation, as opposedto acting as a compromise between English and machine code. Thuswhileotherlanguagestend APLApplied frequently to constrict one intrying to solve a problem, learning and using APL tends to help one to handle the APL's big strength stems from the One estimateholdsthat an APL problem.In fact with experience one abilityof aperson familiar with the programmer can produce a program on seems to be able to write an APL pro- language to write a program as fast as the order of 25 times the speed of a gram while thinking up the method of thinking of the method.In fact one COBOL programmer, (including debugg- solution. Other languages usually re- even tends to think of the solution in ing) and that the resultisof course quire an intermediate block diagram or APLform. Theotherinfluential a far more compact listing. flow chart stage for a similar problem. featureisthat APL isan interactive The proof of this lies in the absolutely language. One point to watch, however,is fanatical following for APL, and the These two combine to produce an that while almost anyone can plough well attended and highly regarded APL ideal way to use a computer for applica- though a BASIC, FORTRAN or COBOL conferences which take place to discuss tions where the programs need to be program (with enough patience),itis applications and possible new features ready fast, and where the applications possible to program in APL in such a for the language. area may be new (and hence the pro- dense andtricky manner as to make We think APL is great for the mind gram is experimental and may require theprogramvirtuallyimpossibleto decipher by other persons. Program- and body, and that it's about to arrive much revision). Thisisnot to say ina big way.This article deals with that in other applications APL is not mers who do this also enjoy reducing what itis, where it's been, and a look suitable,butuntilrecently APL has 100line FORTRAN programs to an at when it should be used, and where been thought of as expensive in terms APL one-liner. (There seems to be it's going. some special attraction to the 'one -line' of execution time and memory use, or challenge!) even simply to obtain access.In add- WHAT IT'S LIKE ition comparedtootherlanguages However, if a program is written with In as much as APL is quite different therearerelativelyfew experienced readingalsoinmind, with a bit of fromother computer languages,has APL programmers, the number familiar descriptive documentation, there is no vastlydifferent qualities, and has with the language will of course grow. problem. 22 ETI CANADA-MARCH 1979 What APL Looks Like

SCALAR DYADIC FUNCTIONS MIXED FUNCTIONS SYSTEM COMMANDS soy X plus Y XpY Reshape Y to have dimensions of X Note. Bracketed words are optional X -Y X minus Y oY Dimensions of Y SoY X times X(Y) /Y-th elements of X /1.1 Allow editing of immediate execution line at boy X divided by Y X 1Y I First locations of Y within vector X position a boY X to the Y-th power Y /V consecutive integers from origin (0 or I) ) MUM= peek' Sign -on-invalid sign -on arts as(BLOT

Y Maximum of X and Y Xe Y Membership of X in Y (BLOT Print a mask for typing secure information XLY Minimum of X and Icy Representation of Y in number system X (CLEAR Clear the active workspace sly X -residue of Y X1). Value of the representation Y in number system X (CONTINUE [SOLD)):lock] Terminate a session and store the active work- XOY Base -X logarithm of Y X?Y /X integers selected randomly without repetition from tY space inCONTINUE X! Y Binomial coefficient. X4.(2)7 Rotation by X along the Z-th dimension of Y )COPYname Hock][list) Copy objects from a workspace 1, items taken X at a time 0(231 Reversal along the Z-th dimension of Y (DROPname) lock) Delete a stored workspace XoY See trigonometric functions 1101 /Transpose of V according to X )ERASElist Erase objects boy X less than Y BY Transpose of Y (01poY)0Y )FNSPotion) List names of functions boy X less than or equal to Y X ,MY Catenate or laminate Y to X along Z-th dimension )GROUPname list Define a group

X equal to Y .r Ravel of Y (makes Y a vector) (GROUPname Disperse a group boy X greater than or equal to Y XtY Take first or last X elements of Y as X is + or - )GRPname List members of a group

X>Y X greater than Y X4Y Drop first or last X elements of Y as X is + or - )GRPS[letters) List names of groups boy X not equal to Y XY X is assigned the value of Y )XEYB LOCK Lock keyboard (to receive messages) boy X and Y IY /Index vector such that 1(51) is in ascending order )XEYB NOMSO Suppress incoming messages XoY X or Y VY /Index vector such that VERY] is in descending order (1118 Return keyboard to normal state boy Not both X and X/(Z]Y X (logical) compressing along the Z-th dimension of )LIB Isom] List names of workspaces in library XvY Neither X nor Y X\(2)Y X (logical) expanding along the Z-th dimension of )LOADname (:lock) Activate a copy of a stored workspace RoX93Y Matrix divide. X approximatesRo .xY )MSGtaskid text Send message to designated terminal 33Y Generalized matrix inverse of Y )MSGNtaskid text Send message to designated terminal without sY Executes the character string Y locking sender's keyboard to receive reply 'Y Character 'representation of Y )OFF (HOLD:Iilockl TRIGONOMETRIC FUNCTIONS Terminate a work session XTY Numeric expression Y is converted to character according to nu- )CPRtext Send message to SHARP APL operator RXoY meric format control vector X )0PRNtext Send message to SHARP APL operator with- out locking sender's keyboard to receive reply below denotes any scalar dyadic function name Pock])'.its) (Y in radians) (R in radians) )PCOPY As)COPY,but protect contents of active WS from being overwritten. X R X R 0 (1-Y.2).5 is\[Z]Y applied cumulatively along the Z-th dimension of Y )PORTSrasa List pan number and task -ID of user an /(2)Y The reduction along the Z-th dimension of Y )PORTS mammon Listpan number and task -IDofuser .1 Sine Y 1 Arcsin Y X..41Y Generalized outer product of X and Y 9999909 2 Cosine Y -2Arsons3 Generalized inner product of X and Y (RESET Tangent I' -3 Arnan Y Clear the )S./ stack e.g.In .14Yis ordinary matrix product of X and 1' )SAVEframe)Hock) Store a copy of the active workspace (10Y*2).5 (-I+Y*2).5 )SEAL Lock allfunctions in the workspace, prevent 5Sinh Y -5Arcsinh Y 6 Cosh Y -6 Arccosh 0 applied to first dimensiont reverse or rotate) dispersal of contents / applied to first dimension tcompress or reduce) )SI Display the state indicator 7Tanh Y 7ArctanhY \ applied to first dimension (expand or scan) )SIV Display state indicator and names of local vari- ables If the expression (5] is omitted, the operation applies to the last )SYMBOLSin) Display/set symbol table size dimension of the argument arr.syY. The expression [2]is 3/0 )TERMInsane! Display/set terminal type. See WS STERMfor SCALAR MONADIC FUNCTIONS dependent. current list of names )VARSPetters] List names of variables 07 OCT dependent )WSID[name] Display/set workspace name -r O -Y 1110 dependent xY Signum Y *7 Reciprocal of Y Fig.1. I. P. Sharp Associates provide a handy reference card for programmers using their systems. It is just x7 e to the Y-th power about all you would ever need to remember or take with you to a desert island equipped with only an APL rY Ceiling of

1.7 Floor of computer, on a scant 224 square inches of card. No more heavy manuals to lug around! Most of the information I Y Absolute value of in this exerpt is general, we have included the section on system commands to give an idea of what is typical. Y Natural logarithm of Y !Y Factorial Y; Gamma Y+ I The special characters shown here are those produced on an impact kind of typewriter terminal. oY Pi times Y ?Y IA random number from --y Not Y of data.Most people are familiar with The concept of using subscripts can integersandrealnumbers, butalso be extended on and on to any number DCT dependent I ELIO dependent letters, words, collections of characters of 'dimensions'.The general term for can be data. all such variables is 'array'. The number Do not confuse, however, character of dimensions or subscripts,it hasis SYMBOLS data with names forvariables. For known as its'rank'. Hence a(b,c,d) O Parentheses for nesting example, in theordinaryalgebraic has rank of 3, a 2 dimensional matrix () Brackets for indexing 0 Quad for input-output expression A=2xB, A and B are variables has a rank of 2, a vector rank 1, and Quote -quad for character input a scalar has rank 0. Quote delimits character literals while 2isa constant. On the other Lamp indicates comment hand, in a computer context it would be Negative sign FUNCTIONS Exponential notation quitepermissibleforC='ABCD', ie APL has a large number of characters Delta. Trace (TA) and stop (SA) control is I-beam for system functions 'ABCD' the'value' of variableC. which denote functions (examples are Decimal point Caret locates errors RANK the familiar + - x 4- but there are many Semicolon separates list elements more exciting ones! A couple of useful 0 Diamond used as statement separator In Branch ordinary algebra we mostly use words to know here are 'monadic' and Colon delimits labels and locks variables of a single 'element', known 0 Squish -quad display of non -printable characters 'dyadic' which mean 'having one argu- as scalars (eg a=2).Sometimes vectors and 'having The following characters are available as graphics: ment' twoarguments' are used, really a list of numbers known respectively.Note that each argument a n by one variable name (eg a=3, 7, 2, -1, ) u may be an array. Thus A+B may yield or a(1)=3, a(2)=7, a(3)=2 and a scala rif A and B are scalar , but if a(4)=-1). 'Matrices' areexpecially they are arrays of the same size and popular for such applications as solution FUNCTION DEFINITION shape, each element of A is added to of complicated equations, and have two the corresponding element of B to make Function definition is opened or closed by V. 'subscripts'. Use of 9 at the close will lock the function. thecorresponding elementofthe The following are valid with open definition resulting array. Example: 10] Display entire function CONSISTENCY AND [.0] Display line n a= 1 3 0 [Do) Display from line n to the end [nOp] Display line n and position at 7 5 4 EXECUTION ORDER p prior to editing 8-7 2 One of the great virtues of Iverson f.001 Display line a and position at right-hand end of line [n] (Re)define line n or a(1,1) =1, a(2,1)=7, a(3,3)= 2, etc. Notation is its consistency. All monadic

ETI CANADA-MARCH 1979 23 vACCUM[O]v 7.4-ACCUM A;B;L of not normally found symbols.Even more symbols are made by backspacing [1] n IMPROVED [2] 444-Ar.+A[;11;] and over striking a second symbol on [3] B4 -A[;11 thefirst. (eg A,I:1and ÷ to make [41 1 -4 -(14,E')11 -11,B E etc). CS] L4 -L,1 Beforenon -APLfansgetturned [6] B4-L/E, off by all this new symbology, it must [7] 414--74AA[f2] besaidthatlearning these symbols CS] is extraordinarily easy, as many of them [9] -.7.(-4,,[:1.5] A remind you of their meaning by their V shape. Twoimportant notestomake: vCHARSCO]v the useof the proper multiply sign Z4 -CHARS X;A (ratherthan an asterisk for multiply

[1] R RETURNS A LIST OF CHARACTERS IN (X>, as in many languages) and instead E2] A SORTED ACCORDING TO THEIR POSITION INAAV of =.This is alogicalchoice since [3] .,ACHAR A -.---A+1 really means 'A is assigned the [4] 2:4-AcX value A+1', rather than 0=1.(By the E5] Z4-Z/A way, APLers often say'gets'rather E6] than 'is assigned the value'). E7J X4-AAVIX,2. In Fig. 1is a listing of APL symbols 74-6AV[X[AIX]] CS] and their meanings, while Fig. 2 shows V 9DEBEMV what a typical output lookslike and Z(..DED X there aremore annotatedexamples 1.1] p DELETE LEADING, TRAILING AND EXTRA it0fX IN (X> in Fig. 3. [.:2] Z4-1tOrX En 4(1.ffX)0-1 ENVIRONMENT [4] The implementation of Iverson Nota- E5i ,vZ4---lt.2):(2vOr 14Z4-Xi07)/X tion asa computer language brought V vDLBDT:0[0]V realmuscle to the elegant notation. 7,74-DLBDTP X As a computerlanguageit is used interactively, thatisto say you sit at Ell R REMOVES LEADING ANDTRAILING BLANKS FROM TEXT INPUT (X) E2] Z4-((v\Z)A0v\OZ.4-Xix!' a terminal(orat your personal APL V machine!)and communicate directly and immediately with the computer. VCOMPRESSNAME[O]v You have the option of typing a 7..4-COMPRESSNAME NAME;L statement and obtainingits result on E1] N AN ALGORITHM FOE: NAMECOMPRESSION Cl] DELETE SECOND ELEMENT OF REPEATED CONSONANT PAIR the spot (immediate execution mode), E23 A writing a function or program (function En rf [2] DELETE ,AEIOUY. EXCEPT WHEN FIRST LETTER IN NAME [4] 1ST STATEMENT IS NOT ABSOLUTELY REQUIRED definition mode), and executing such CS] a function or program (again - immedi- E61:1 4(pNAME4-DED NAME) 4p::4-' ate execution mode).Various editing [7] 4-,,L4-NAMECAEIOUY. and line numbering facilities are pro- 1.8] L4-(0,14L),,NAME=14,NAME, vided for function writing, and diagnos- C91 4-L/NAME tics and error messages help to debug V functions. Fig. 2. Another example of what APL looks like, this printout from a DEC dot matrix terminal. The resolution is not quite as good, nor the resulting characters so exotic THE WORKSPACE looking, but the terminal is faster and quieter. On 'big systems', each APL user has a 'workspace', a fenced -offpiece of memory, as it were, of some arbitrary functionsarewrittenwiththe one left,regardless of functions (ie x does size, say 50k bytes, where all his work functionsymboltotheleftof the not take precedence over +). The order isstored,allvariables functions and argument, such as !F which means the may be changed using brackets.This programs, and in which the programs factorial of F, ÷X whichis the recip- order isconsistent with the normal areexecuted. On completion ofa rocal of X, or ?Y, a random selection use of functions such as sin, log, d/dx session the user can store his workspace, fromthefirst. Y integers,whileIA etc. even including partially executed pro- means absolute value of A. And remem- grams,as complete state information ber F,X,Y and A could be arrays! In THE APL CHARACTER SET is contained in the workspace.This fact, the APL user tends to think that In ordertowriteall functions storingprocessisusually onto disk, the basic data form is the array, which compactly, alarge collection of new and is done ina relatively fool proof occassionally 'happens' to be a scalar or symbols was designed, whichis now way as the user signs off.The work- vector. fossilizedin the type elements of var- space then sits in suspended animation, Similarly,alldyadic functions are ious impacttypeterminals. These awaiting theuser's continued efforts written with the symbol between the usually have all the upper case letters, next time. two arguments. plus numbers and punctuation and so A user mayalso copy functions Finally, execution order isright to forth, and of course quite a selection from another workspace into his own, 24 ETI CANADA-MARCH 1979 APL: Good For The Brain

E: PETRY ENTRYa lows the user to enter a list of names, (if so permitted) which of course gives E`E-1.0111 one at a time, alloting ten characters to each name, AE -A and filling any unused positions with blanks. access to alot of useful software which ENTRYstops if the user types a single "*". The resulting vector isA. others on the same system have develop- V ed. VRESHAPE RESHAPEchanges the list of names from a vector OTHER BIG SYSTEM APL C(((PAH-10),10 to an array with one name per row. FEATURES p A Just as a user may copy information OP DE F: fromanother workspace, so can he D, E.EALPHAI ORDERtakes the array makes a numerical array accesssystem'libraries'wherelarge E whose entries represent the letters inD,according toALPHA. Eis sorted by row, and the new order is volumesofsoftwareare typically then imposed onD.Job finished! found, such as routines for plotting, NE -10 various engineering, statistical, and work F4-F[4.F[AN];] processingpackages,andofcourse 1144-1 games. 45+3)04=0 Additionally, extensive file systems D4-DEF[ ;11 ] (usually disk) are generally available for storing large amounts of program code Below, the functions in action. or data. ALPHA APL CHARACTERS ON ABCDEFGH/JKLMNOPORSTUVWXYZ EXISTING MACHINES ALPHAis the vector variable to which we assigned the How do you put APL on a machine deSired organizing sequence. It's value is the character E Ni T F: "blank'" followed by the alphabet. Other orders or which has no APL character set? While characters could have been chosen instead. new machines will be able to display JOHN the characters,and newcharacter User types"ENTRY",the the function waits FF:ED for the users entries, until it encounters the """. generator ROMs maysatisfy a few ANDY other ways around the problem are possible. A One isto use three to five letter JOHN FRET.. ANUT The resultingAand 6 values afterENTRY. keywordsinsteadofsymbols,such a single signifythe that key could RESHAPE: function, and the whole keyword pops onto the screen.This doesn't provide RESHAPE,and the resulting C andDvalues. an elegant looking display, but it does 4 10 give you APL with only a small sacri- fice. JOHN IMPLEMENTATION ON MICROS FRED Theworkspace,libraryandfile ANDY concepts are more system dependent than theIverson Notation part of APL. ORDER They are alsolikely to be seen only E in limited form at first on small systems. User executes the function For instance, one workspace islikely 11 16 9 15 1 1 1 ORDER,and the resulting 7 19 6 5 1 1 values ofE, L,F, and finally tobe almost theentire memory of what we were waiting for ... 15 5 26 1 1 1 1 a micro -based machine, so there will D,now in order. 28 1 1 1 1 1 1 1 be only one user at a time.A disk unit will be essential, for storing work- L space(s) and files, and one will presum- 4 ably be able to create one's own librar- F ies,or buy library disks with various useful packages on them. 2 15 5 26 1 1 1 1 3 7 19 6 5 1 1 1 1 1 2 'Virtual Workspace' schemesare 11 16 9 15 1 1 1 1 1 1 already being worked on, wherein the 28 1 1 1 1 1 1 1 1 4 user thinks he has a large amount of memory available, wheninfactthe L ANDY machine hasonly a smallamount, FF:ED but swaps portions of the workspace JOHN

on and off a disk as they are needed. A This requiressomefancymemory management to accomplish effectively. 9 EXAMPLE [1] 0,.. Fig. 3. An example of how to sort a list of ENTF:Y EXAMPLEis a function which ties these [2] three functions together into one, and names. The 3 functions are listed at the top. F:ESHAPE Below is a series showing what the user did [3] then prints the result out. (indented), and what the machine's response [4] ORDER was.(Yes, we know it could be done in one [5] EI' line or less). V ETI CANADA-MARCH 1979 Want to read more about electronics? See card facing page 3. 25 'This historic photograph was taken in the hospitality suite at the recent APL users meeting. From left to right are Dick Lath well, Ken Iverson, Roger Moore, Adin Falkoff, Phil Abrams and Larry Breed. It is believed to be the first time thatall six originators of APL' have been in the same place at the same time, it is probably the first time that all six have worn jacketsand ties simultaneously and the first time that Ken and Adin have been observed to smile simultaneously." Reproduced by kind permission from The I. P. Sharp Newsletter.

Where has APL Been?Not hiding, just expensive?

It was in the late 1950's that Kenneth their Toronto systems via a vast com- thesedaysthatmicroprocessorsare Iverson,a Canadian,atthat time a munications network. the way to go but at the time develop- professoratHarvardUniversity,de- What was needed was a stand-alone ment started onthat MCM machine veloped his notation system. Iverson type machine which was inexpensive, people were skepticalofseeing any Notation was intendedfor analyzing inorderfor APL to be worthwhile kind of high level language on a micro, and communicating problemsinin- forthe smalleruser,or even as an let alone APL, and especially on the formation processing which he and his educational tool. Stepsinthat way 8008! More on thisin'The MCM students were involved with. were takenwithIBM's 5100 series Story'. Iverson and IBM joined forcesin (a dedicated APL machine which pre- 1960, and there, with the help of those tended to be a 360 cpu and thus could RECENT MICRO MOVES fellows in Fig. 4, IBM's APL interpreter run the 360 APL interpreter unchanged, Untilrecentlytherehasn'tbeen resulted. includingbugs!),also machines from much stiringinthe way of APL for Hewlett Packard and DEC. themicrocomputersystem, inthe way BASIC hasbeenavailablefor For a long time, APL was only avail- THE MCM MACHINE every microcomputer around. abletothosewithaccess large to In what might seem like attempting Now, suddenly there appears to be computers, which madeitexpensive to win the Indianapolis 500 on roller a terrificbattle brewing, as the race togetinto,but the enthusiasmof skates, MCM Computers,(a Canadian is on to feed APL to what is expected those who could use it was extrordin- company!) in1974introducedthe to be an open-mouthed market. Judging ary. So much so,infact, thatI.P. Sharp Associates now provide addicts MCM70 a desktopAPL computer by the almost astounding enthusiasm of withoneline in Europe, North America, Scandinavia alphanumeric display, current APL users, each new user will and Australia with access to APL on keyboard, dual cassettes and was based be spreading the word far more quickly on the 8008! It might be obvious than was true with BASIC, that is if he 26 ETI CANADA-MARCH 1979 Where Is APL Going? Microsoft's Bill Gates has a bit to say.

Microsoftisa name in the micro- computer software field regarded with a great dealof awe. The US trade magazine 'Electronics' describes Micro- soft as a'small...software house', but with customers like Radio Shack and Commodore(TRS-80Level II and PET BASICs) who are the leaders in consumerizedhome computing, and a hugelistof other microcomputer companies,Microsoft hasto be the major 'force' in micro software. BillGatesisthe president of the company, and the APL jobislargely his baby. So we asked him for his views on the micro APL scene. NEAR FUTURE What is about to happen in the way of micro APL? 'APL will see an incredible increase Fig. 5. Here's what the MCM 900 system looks like. This collec!ion costs around $20,000. The keyboard -display unit contains the guts. The display itself is a 12 inch screen with 21 lines in popularity because it will be exposed by 96 characters. to so many new people.To date, it has been an expensive language to use and is almostneverintroducedto can tear himself away from the console! will be ready with the 16 bit versions firsttimecomputerusers. APL's inearly1980. Vanguard are hoping strengths assure that a significant VIDEOBRAIN to manage the same feat. percentage of personal computer users First out with APL appears to be will adopt it as "the language".How- Umtech withtheirF8 based Video IT'S COMING! ever itis not the ideal first time langu- Brain. Fitting into 13k - worth of Well,it's almost here. It appears age and has some limitations of its own. ROM -in -a -cartridge, APL/S isa subset that the development of APL on a 16 BASIC will continue to dominate in of'fullAPL', although there isno bit microprocessorwill make the this role, although specialized languages standard APL. While a standard for first really comfortable implementation will be supported by personal computer APL is being worked on, big machine of APL for personal, home, business manufacturers. Microsoftwillintro- versionsprovide a referencewhich or educationaluse. Because of this duce APL on the TRS-80, Exidy Sor- differs only slightly from one to an- general purpose naturemost new cerer,Interact One, Nascom and NEC other, and then only in housekeeping APL machines will be easy to use and TK-80 in 1979. facilities rather than in the basic nota- henceeithercontain APL on ROM Also the old time APL users will tion. (fool proof) or on disk (most machines enjoy the low cost and ease of access Z80 AND VANGUARD will have a disk or two anyhow). to the low priced machines. These old Vanguard Systems Corp. have an- nounced an APL interpreter on floppy disk for Z80, and of course all compan- ies with Z80 based machines are eagerly waiting for it.It is reported to be 27K. MICROSOFT Meanwhile, over at Microsoft, much brain work is going into the develop- ment of APL interpreters for all kinds of processors, past present and future, ie 8080, Z80 and the 16 bit micros 8086, Z8000, and 68000.Bill Gates, president and APL Product Manager Fig. 6. This is the Exidy Sorcerer, which currently runs BASIC language. Plug in ROM -PACs, at Microsoft figures fall '79 will be the just visible to the right, will allow the use of other languages, with APL to be ready in the timehis 8080 and Z80 interpreters fall. ETI CANADA-MARCH 1979 27 time users will be key in generating new Availability ofallprimitives normally product was the MCM 70 desktop APL converts. New tutorial material making found. computer, which wasbased on the APL seemless mathematical and not Sophisticated system commands, error 8008thefirst8 bit microprocessor. forcing the user to see the utility of messages. This model was quickly superceded by all the operators will be required. The Initially only SAVE and LOAD work- the MCM 700 which was aslightly statistical, accounting, and model type space 'file' operations, but later random modified version. This machine had dual applications that APL isexcellent at access I/O on arbitrary objects. cassettedrives,andonelinealpha- willbe key ones for the new small Later on Gates thinks 16 bit APL numeric display. 32K of ROM con- business computers. With APL's fol- willhave up to 10 meg workspaces, tained the interpreter, with 2K RAM lowing, IBM's supportofitandits same libraryfacilitiesasI.P.Sharp. provided, expandable to 8K.The 700 strength, our OEMs have decided they Significantly, he comments that many even came with battery power, enough can't ignoreit. Our response on the language extensions may be persued, forthe APL addicttogethisfix product to date has been incredible.' something hefeelsIBM hasstifled. anywhere! This machine was offered for 'APL should not be allowed to stagnate. about $8000 in 1974. FIRST VERSION Itisvery weak in control structures. Kutt left the company in mid 74, Detailsof the 8080/Z80 version: General lists should be added.' and in the spring of 75 Ted Berg became 'Our 8080/Z80 version (long await- it's president. ed) will be out in April running under Inmid 76 the company's second CP/M. Otherversions such asthe AN EXCITING NEW COMPANY model, the MCM 800 was introduced. virtualworkspace onewillfollow.... Startinga new company can be a Because the APL interpreteralready Equivalencewith the 5100 was my thrill,anditsoundslikeMicrosoft developed was so good, but the 8008 a is an example: goal - and I met that with 24K of little slow, the 800 was centred on a code. 'Paul Allen and I started Microsoft in CPU board built with a couple of ALUs We will license our APL to most of November 1974. The incredible po- and other supporting chips imitating the our existing OEMs.' tentialforthe microprocessor when 8008.This resulted in a computation combinedwithgoodsoftwarepre- power improvement of around 10 over sented a unique opportunity for us to the 700. The 800 is generally used in a PERFORMANCE start on our own.The conventional system withdualfloppy disks, with What kind of performance is expected languagesand our enhancements of perhaps a printer. About $9,000 could from micro APL? them (BASIC, FORTRAN and COBOL) get you the 800 itself, which incorpor- 'Microsoft APL has all the features have kept us extremelybusyand ateda VDU and single cassette, and of IBM APL/SV (360/370) APL except delayed ourintroductionofAPL came with 8K RAM. that theI/O and shared variables are for over 18 months. Providing these Inmid'78,Berg moved to take handled differently and the math will packages for the 16 bit processors as on MCM's US distributorInteractive not be totally the same since we use wellas our new 8 -bitproducts: a Computer Systems Inc. The company's binary exponents where IBM uses hex. BASIC compiler, a Data base manager, new president, Chuck Williams explains Our APL is twice as fast as the 5100 a PASCAL based systems programming thatwith MCM'sthird generation which is very adequate and often better language and of course APL, will be machine, the MCM 900, the marketing than remote APL timesharing systems. our primary emphasis in 1979. strategy can now be more solidly aimed Our 8086 and Z-8000 APLs will be at The APL projectwasstartedin at a wide market of business applica- least five times faster and will be avail- January1976. At one time people tions. The 900 is based again on an ableinearly1980. This APL will haddoubtedtheabilityofmicro- 'imitation' high speed 8008, using a outperform APL on most minis. processors to support high level langu- pairof 29014bitsliceprocessors, The string search and block transfer ages. After BASIC had disproven this, giving an increasedperformanceof are an advantage that our Z-80 version APL seemedlike a great follow-on 5-10 over the 800 according to John willuse. In specific cases this could product. APL provided a new challenge Koiste,GeneralManagerofMCM's cause a 2:1 speed difference, but overall because of its complexity and require- Kingston R & D and production facil- theZ-80 to 8080 difference willbe ment forlots of memory. However, ity.Williams likens this improvement lessthan 15% at equal clock speeds. FORTRAN gothigherpriorityand from 800 to 900 to the production of More important are the design tech- only one person was left on APL after automobiles with top speeds of 60 and niques which allow a 32K byte work November 1976. FORTRAN was 80 miles an hour.While the perfor- space to be equivalent to almost twice introducedinJune1977. COBOL mance improvement is relatively small, thatmuch workspace onthe 5100 was introduced in June 1978. and the first car will accomplish trans- throughmoreefficientmanagement Microsoft now employs 14 full time portation, thereisa certain threshold and special representations.' technical people and has moved to new levelat which the product becomes and bigger offices in Seattle, Washing- widelyacceptable. This,Williams FAR FUTURE ton, as well as purchasing a DEC 2020 feels,has happened withtheir900, for in house development.' whichstrongly competes with time- Looking forward about a year sharing andothermoreexpensive Gates sees some of the following fea- THE MCM STORY models. The 900 itself is priced around tures being offered: This company, based in Toronto and $10,000, but is really intended for use Workspaces upto 40K with virtual Kingston Ontaio, has had a very interes- witha dual disk and printer. Essen- workspace to follow. tingpast,anda unique partinthe tiallyitispart of an $18 - 20,000 Libraries on disk. development of APL machines. business problem solving package. Unlimited number of dimensions for Inlate 1971, early 72, two fellows Asforthefuture,Koiste admits arrays. by the names of Mers Kutt and Gord that MCM has gone about as far as it 16 digit computation (floating point) Ramer started the company. Their first can withusing the 8008 interpreter 28 ETI CANADA-MARCH 1979 APL: Good For The Brain and will have to develop new software the software.The produce was based SUGGESTED BOOKS around 'more up-to-date technology'. on a GI 1600 microprocessor, and was This we take to mean they are looking to have floppy disk(s) and some colour Kenneth E. Iverson: "Elementary at 16 bit microprocessors.Meanwhile, graphics capability. The APL inter- Analysis"; APL Press, 1976. preter,whichwas developedon a Williams saysheisn't worried about The APL Press has available a comp- simulatingGI code,has competition from the hobby computer PDP11/34 rehensive collection of publications on even as they pursue dynamic workspace management, manufacturers, APL. the interested reader should write He floating point numbers, but only one APL on 8 and 16 bit machines. for a complete list. feels his personnel and their experience dimensional arrays. 16K of 16 bit words are the company's strengths, and that was, required. Unfortunately the whole Leonard Gilman and AllenJ.Rose: they willstay ahead of the game in combination was never tested as interest "APL An Interactive Approach"; John the business market, where they have in further development has appeared to Wiley and Sons Inc, 1974. lapse. Anybody want to take over an seven more years of experience than A. D. Falkoff, and K. E. Iverson, "APL almost debugged GI 1600 APL?Call the newcomers. Language", IBM Corp, 1975 (Form No. Sharp. GC26-3847)

I. P. SHARP IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII 11111111111111111111111111111111111111111111111 11111111111111111111111111111111111 An interestingstory came to our attention recentlyin connection with ACKNOWLEDGEMENTS micro APL. I.P.Sharp Associates, ADDRESSES known worldwide for their APL com- Our thanks to the following people who were very helpful in the prepara- APL Press, Box 378, Pleasantville NY munications networkand software 10570. expertise, were apparently working on a tion of this article: micro based APL consumer product! ExidyInc.,969 West Maude Ave., Sharp'sSteve Kohalmi described the Bill Gates, Microsoft; Sunnyvale, CA 94086. project. A major Canadian manufacturer Chuck Williams,JohnKoiste, MCM of entertainment products went to Sharp Computers; MCM Computers Limited, 6700 Finch with the idea, and developed the hard- Steve Kohalmi, I. P. Sharp Associates; Ave. West, Suite 600, Rexdale, Ont., ware prototype while Sharp worked on I. P. Sharp Newsletter M9W 5P5.

NEW LOW COST LX303 DMM

SPECIFICATIONS:

DC VOLTS (5 RANGES):0.1 $99.95 mVto1000V; Accuracy±0.5% rdg ±0.5% f.s.;Input imped: 10M ohm; Max. input 1kV except 500V Operates up to 200 hours on a single 9 on 200mV range. AC VOLTS (40Hz to 5kHz): 0.1V to 600V; Accuracy: volt battery.100 mV DC f.s.sensi- ±1.0% rdg ±0.5%f.s. (-2db max. at tivity.Features auto zero, polarity, 5kHz); Max. input: 600V. overrange indication. Nineteen ranges RESISTANCE(6 LOW POWER and functions. With easy -to -read Y2" RANGES): 0.1 ohm to 20M ohm; LCD display forconvenient use Accuracy:±0.5%rdg±0.5% inanykindoflight.Removeable (±1.5% rdg on 20M ohm range); stores inputprotectedto120 VAC all cover test lead set furnished ranges. as part of the unit. Excellent overload DC CURRENT (6 RANGES): .01nA protection. Colour coded panel. Car- to100mA; Accuracy:±1.0% rdg ries a full one year warranty. Avail- ±0.5% f.s. able accessories include 10 kV probe/ DIMENSIONS AND WEIGHT: adapter, 40 kV probe, 10 amp DC 5-7/8"x3-3/8"x1-3/4", 8oz.; shunt, AC adapter and deluxe padded POWER: 9V battery (not included) vinyl carrying case. orHickok AC adapter;READ RATE: 3/sec.

Duty and FST included. Chargex (Visa) accepted. R O G E R S electronic initrunienti ltd. HICKOK Ont. res. add 7% sales tax P.O. Box 31G, 595 Mackenzie Avenue Units 1 & 2. the value Innovator F.O.B. Ajax. Ajax, Ontario L1S 305. Tel. (416) 683-4211

ETI CANADA-MARCH 1979 29 NON -SUBSCRIBERS START HERE Quality Computer

HE DEPARTMENT STORE: *******'" Products THE CORNER SHOP: "MAGAZINES ? THAT'S JUST 'SORRY MATE, THE BEHIND COSMETICS. NO, DOG CHEWED YOUR WAIT A MINUTE....THEY'VE COPY." JUST MOVED TO THE NINTH Now available in Canada from FLOOR, OR WAS IT ," -gClIVIPUMART The Personal Computer Store

MEMORIES for the S-100 Bus Econoram IITM (8K) Unkit $215 Assembled $249 Econoram I V Tm (16K)Unkit $439 Assembled $479 Econoram VI ITm(24K IUnkit $679 Assembled $729 NEW! Econoram XTM (32K)Unkit $939 Assembled $989 FEATURES: Fully static memory. Dip switch address selection (no wire jumpers). 450 ns access time. High quality, double sided,platedthrough,solder masked and legended circuit board. Sockets for all ICs. UNKITS: Sockets, bypass caps pre -soldered in place for easy "SORRY, SOLD OUT as,,k;r111,Iy. HAVE YOU TRIED THE 4 MHz operation guaranteed for Econoram X. CORNER SHOP UP THE ROAD?" MEMORIES for other Buses HEATH H-8: 12K Econoram VITM Unkit $325 Assembled $395 NEW, DIGITAL GROUP: 32K Econoram IXTM Unkit $995 NEW! SBC (Intel/National 80/10 and 80/20 computers). 32K Econoram X ITm CSC* $1595 STAND: "WE'VE RUN OU.T, TRS-80 Conversion Kit: Upgrade, your 4K TRS-80 to 16K for BUT I CAN GIVE YOU only $215. Complete with DIP shunts. 1 Year warranty. 'CAMPING NEWS' ," I OTHER S-100 PRODUCTS from Godbout ACTIVE TERMINATOR KIT: Promotes reliable accurate data transfer by minimizing ringing, crosstalk, other noise only $49.95 11 SLOT S-100 MOTHERBOARD UNKIT: All 11 edge conn- ectors soldered in place. Includes active termination... $149.00 GIVE UP, GO HOME: AND TAKE OUT A 18 SLOT S-100 MOTHERBOARD UNKIT: 18 slot version of POSTAL SUBSCRIPTION above $195.00 TO ETI NORTH STAR PRODUCTS COMPUMART sells only the best equipment available. North Star's HORIZON Computer, now available with double density It can be a nuisance can't it, going from newsstand to diskette drives (180K bytes per diskette) satisfies our exacting requirements. Write for further information. Kits from $2359, newsstand? "Sorry buddy don't have it - next one Assembled and tested from $2759. should be out soon." Although ETI is monthly, it's very rare to findit APPLE IITM available after the first week. COMPUMART is Ontario's largest dealer of this high quality personal computer system. 16K systems start at $1775. Write Do yourself a favour. Place a regular orderfor ETI with for further information. a postal subscription, so there's nothing for you to remember - we'll do it for you. *CSC (Certified System Component program). 200 hour burn -in, guaranteed 4 MHz operation over the full comm- For a subscription, send us $14.00 (12 issues) or ercial temperature range, serial numbered, immediate replace- ment in the event of failure within 1 year of invoice date. $26.00 (24issues).For US addresses the rates are Also available for Econoram IV ($639), V 11($919). X($1195). $17.00 and $32.00 respectively. Do not send cash. TERMS: Visa/Master Charge (Please include Credit card orders give card name and number, expiry expiry date), check or money order. Add date and signature. Allow six to eight weeks for first issue. 2% for shipping and handling. Ontario resid- Place your order on the convenient order card. ents add 7% Provincial Sales Tax. Send to ETI Subs Dept, Unit 6, 25 Overlea COMPUMART, P.O. Box 6132, Station J, Blvd., TORONTO, Ontario M4H 1B1. Ottawa, Ontario, K2A 1T2 or phone (613) For overseas add $5.00 per year to Canadian rates. 725-3192.

30 ETI CANADA-MARCH 1979 ETI Project Tape Slide Synchronizer Tape Slide Synchronizer

This unit will let you tape record a commentary for your slide show, so you can even give a talk without being there...

WHEN PUTTING ON a slide show for your friends or a business meeting, it is usuallynecessaryto have some commentary with it. If it is a one-time presentation this is no problem, but if the show is to be repeated or if you simply want to be able to recall good memories a couple of years later then a tape recording of the commentary is ideal. The problem now is to keep the slides changing in synchronization with the commentary, without having to record that obtrusive phrase 'change slide now' onto the tape. This unit allows a control tone (120 Hz) to be recorded on the tape along with the normal voice recording; when replayed the tone will activate a relay which will change the slide while a notch filter removes the tone so it is not heard through the speaker. An earlier design recorded the tone on the second channel of a stereo recorder. While this worked well, a stereo recorder is not always available, and this design allows an economical mono recorder to be used. If you cannot find an appropriate insert mounted just behind the front panel. Thin adhesive vinyl was used CONSTRUCTION pc. mounting transformer, you can of course use a chassis mount type and to cover this panel, with a 25 mm dia. Assemble the pc board with the aid of omit the end of the pcb. hole behind to allow the panel to the component overlay in Fig. 1. With vibrate and transmit the sound to the the 120V wiring it is better not to use We built the prototype into a large microphone. However the noise of pc pins but solder the wires directly plastic box with the controls on the the relay operating could be heard on onto the pcb. A covering of epoxy glue front panel and the tape recorder/ the tape and therefore an external over the tracksleading to the amplifier connections on the side. The microphone is recommended. A socket transformer willhelp to prevent wiring of the front panel is given in can be mounted on the front panel in accidental contact. Fig. 3. We used an electret microphone the microphone position. ETI CANADA-MARCH 1979 31 ETI Project

-12V D3 D5 1N4001 1N 4001 IN IC1 OUT 781_05 5V DI 1N4001 ,C6 10p 0 120V AC OV 0 SW1 GROUND T1 +IC2 0-1.20V 1 8VCt/ 1000., .25A 16V 02 D4 1N4001 1N4001

12V

Pb 1

- R6 470k

MICROPHONE (ELECTRET) C7 R5 1..0 lk R8 100R OUTPUT TO TAPE RECORDER

OV

R10 INPUT FROM RECORD R9 100k TAPE RECORDER 100k 08 C9 0 - lOrt 10n PLAY sw2 10 R17 5 LN1324 100R OUTPUT TO 9 LM324 AMPLIFIER OV R13 non n 10K R11 220k +12V RV2 R15 50k 1k

C11 47n a A gRL I I 08 R14 120K 1N914 13 C13 Q1 2N3904 R19 IC2/4 R22 100k LM 324 2k2 12 b 1N 914 +12V D6 R18 C12 220k 1N91441 LED 1

NE567 OV ()V

2 41 ,C14 L,C16 T22p 33p

OV

32 ETI CANADA-MARCH 1979 Tape Slide Synchronizer

- HOW IT WORKS - 0dB

With this unit, unlike our previous design, we record a 120 Hz tone burst on the

same channel as the speech whenever we 10d13 require a slide to be changed. The tone is derived by full wave rectifying the output of the transformer and filtering out the 4-- harmonics by R2,3/C3,4. Pressing the slide change button mixes this tone with the output from the micro- -20dB phone which is amplified by IC2/1. This combined output is recorded on the tape. In the record mode SW2 connects the output of IC2/1 to the buffer amplifier IC2/2. In the playback mode it connects the output from the tape recorder to the amplifier. The output of this amplifier 30d8 issplit into two paths. One of theseis through a 120 Hz notch filter to IC2/3 effectivelyremoving the 120 Hz tone without much change to the rest of the isusedtodrivean spectrum.This 40dB amplifier/speaker system. 24 60 120 240 600 The other path for the signal after IC2/2 FREQUENCY HERTZ is via a low pass filter IC2/4. This removes frequenciesabove150 Hz andhasa response as shown infig.3. When the 120 Hz tone occurs, this filter passes it, rejectingspeechfrequencies, anditis passed to IC3. This is a phase locked loop tone decoder and its output on pin 8 turns on when the correct frequency toneis received. The output stage of this IC is an open collector npn transistor which can sink but not sourcecurrent. With no incoming tone this transistor will be off, ADJUSTMENTS USING THE UNIT preventing any emitter currentin01, hence turning it off also. The voltage on Set the unit up to record and with all With this unit a separate amplifier/ the base of Q1 in this case will be set at speaker system is needed. Also the slide 1.6 V by LED I. When a tone occurs the trimpots at the centre of their travel and output of the IC will saturate to about the microphone level at minimum, hold projector must have a remote change 0.6 V, forward biasing Q1, turning it on, the slide change button down. Probably button using normally open contacts. and closing the relay. The current in R22 some 120 Hz signal will be heard on the Connection has to be made between isnow bypassed into the base of Q1, output of the amplifier. Alternately these contacts and the relay in the unit. giving about 1.2 V on the base. This is too adjust RV2 and RV3 to minimise this Check that these wires are isolated from low for the LED to conduct and it will go signal. It should be necessary to wind the 120V line and if not be very care- out. up the volume of the amplifier to finally ful with the connections. The power supply is simply full wave adjust for a minimum level. Connect the unit to the tape recorder rectified and filtered for IC2, and a 5 V and projector, assemble the slides in the regulator is used for the PLL IC and the The other adjustment is of the phase microphone amp. locked loop centre frequency. With the correct order and switch on. With the push button pressed slowly rotate RV4 record/playback switch in the record until the relay either opens or closes. position and the recorder set to record, If it closes, continue to rotate it until it commence the commentary, changing The pcb for this project Is available from drops out then bring the pot back to the slides with the button on the unit. The Spectrum Electronics, 38 Audubon St., S. Hamilton Ontario L8J 1J7 and from half way point. If the relay opened, high level input on the recorder should B & R Electronics, PO Box 6326F, reverse the rotation to find the other be used and the microphone level pot Hamilton L9C 6L9. point at which it opens and leave RV4 set to give the correct recording ievel. midway between these two points. When playing back simply set the Check the operation of the relay record/playback switch to playback and when pressing the button. There should replay the tape. be about half a second delay before it closes. ETI CANADA-MARCH 1979 Please mention Electronics Today when responding to advertisements. 33 OUTPUT TO OUTPUT TO PROJECTOR OUTPUT TO TAPE RECORDER AMP Li Flfi R

RL1

D2 DI 04 03 G7 D5 96 C 006 b

C16

(;120UND

?POWER CORD

Fig. 3. The component overlay and wiring diagram.

PARTS LIST SW1

RESISTORS all '12W,5% R1, 2 3k9 R3 18k R4 1M R5 1k R6 470k R7 150k R8 100R R9,10 100k R11 220k R12 100k R13 10k R14 120k R15 1k R16 10k LED PUSH R17 100R BUTTON R18 220k R19 100k R20 1k R21 8k2 R22 2k2 INPUT FROM POTENTIOMETERS TAPE RECORDER RV1 1k log rotary RV2 50k trim RV3 100k trim RV4 SEMICONDUCTORS 5k trim MISCELLANEOUS IC1 78L05 PC board ETI 553 1C2 LM324 CAPACITORS C8, 9 10n polyester Relay 12V 28011 C1, 2 1000µ 16V electroC10 22n polyester IC3 NE567 (8 pin) Transformer 120V - 18Vct/.25A C3 1µ0 25V electro C11 47n polyester Q1 2N3904 Two toggle switches C4 330n polyester C12 2n7 polyester One push button switch N/O D1-D5. . . .1N4001 C5 10n polyester C13, 14. . . 1)10 25V electro Box to suit D6-D8. . . . 1N914 C6 10µ 25V electro C15 22µ 10V electro 3 wire line cord C7 1)10 25V electro C16 33µ 10V electro LED Output sockets etc.

34 ETI CANADA-MARCH 1979 Tape Slide Synchronizer - o

0

ETI553

co

MnnnfOOEBIIMOMIOMOOESIIIIIIIIMOEMOSMIMIIIIOIIIIIIMM OlIMMIIIIIIIIMII IIMIIIIIIIIIIII Emmons emelsomm000mme IIMOSIIIIIIIII ' MEMO NINE .111 SO .-.11 .--II ..11111111- ..8 .--M .--.. _gm' la 'Ill Mr.---II .-,'M MI '111' !.,.. VI 11.1"..,- N1 MM. MI.0111 '''il:_:1111 ''. .,, 11A "...AOI IMI -7'1IIIMIE ''''.0 -.1 i IL-7-1M. SD 7'00 --,M IMIIIMIIII MINIM m A IIM `1 .6..=IL ammomeO -NMI --.O21 ii. _7-.111 Of ILIM ISO ''''.111, Au 11lin ..1 11111":411.1.11111111 IL WM ill AMMO WHAT MEASUREMENT WOULD YOU LIKE TO MAKE?

Oscilloscope Model No. LBO -508A

Bandwidth: 20MHz

Sensitivity: 10mWcrn DMM Model No. LDM-851 Autopolarity -- - 3'h Digit LSI Circuitry Semi -auto ranging

NTSC Pattern Generator Distortion Model No. Meter LCG-396 Model No. LDM-170 Variable Video Output S/N Ratio to -70 dB Measures Distortion as low as 0.1% Progressive and Interlace Scanning

"WE'RE ON YOUR WAVE LENGTH"

LEADER TEST INSTRUMENTS IFLP51 omnitronix ltd. 1:'..;-.1!;2":;12.1.:.itia...1.;1:: 2056 SOUTH SEHVICE RD TRANS HWY "PUT US TO THE TEST."WRITE FOR OUR DETAILED CATALOG. DORL,VACANADA OUE H9P 2N4 PHONE: (514) 683-6993

ETI CANADA -MARCH 1979 35 FX

A CLOUDY, SNOWY midday itis, and the feeling of pressure in the air is so thickyou could cut it with a pair of wire snippers

. . . although not really the kind which are actually mostly intendedas wire strippers and are quite thin and flimsy, you would probably have to resort to quite a chunky pair to make a dent on it. The reader is usuallynot aware of what goes on behind the scenes at a magazine, so I'll tell you. "Next month in ETI" is thelast thing we normally do on the magazine. The last piece of the puzzle. We are all tired, after the end -of -issue rush,and thinking about what we have to do next month doesn't fill us with enthusiasm. In fact,we just want to go over to the plaza for a sandwich at the deli. Except I'm going to have a fish -on -a -bun, and Mark wantsa milkshake from the ice cream shop. Gail will probably go to the other deli for a .soup, and when she gets back she wnll be furiouswith the deli counter lady for not attaching the soup lid tight enough so that the soup will all leak into thepaper bag and then onto the carpet at the office. Meanwhile Sharon is buried under mounds of typing, and Senga is valiantly tryingto figure out where the extra penny went. Bebe is pacifying a subscriber on the phone who wants to know why the post office still has hiscopy, and please don't cut off his subscription just because it has expired, since he hasbeen in Brazil for the last three weeks and has been unable to renew; and with the other hand she is mediating/lightingwith the magazine mailers and post office to try and get them to talk to each other and agreeon how to mail magazines. In the next office Steve is encou- raging the printers to move faster, and generally makingsure the ETI crew don't go berserk by looking into the pos- sibility of more S -P -A -C -E for the workers. There's also the continuing debateover glossy paper for the magazine, (what will the readers think, well?)...... all in all, a potentially explosive situation. All it would take to set things off wouldbe a phone call from Wally. By the way, next month we've got a bit about solar power for heating houseor pool, how it's done, and a project to build the essential electronic portion of the system, the ETI Solar Differential Temperature Controller.There's also an Audio Compressor project, and Wheel of Fortune with sound effects. Learn about DesigningAudio Amps, and about RF Chokes (more than just a bit of wire you know!). And, oh yes, next month is... April ... It's faster, easier and lessexpensive. That's why .... s'S we call it ...

Super-Stripm. 410 _ - -

This versatile mini breadboard fea- DISTRIBUTORS tures the same superior contacts, Montreal, Quebec 514-735-6425 materials and construction we use in Montreal, Quebec 514-769-8861 Quebec, Quebec 418-647-4422 our full-scale ACE All Circuit Evaluators. Toronto, Ontario 416-484-9708 Any solid hookup wire up to #20 plugs right in to Downsview, Ontario 416-663-5563 connect DIPs, discretes and almost any components Ottawa, Ontario 613-820-9471 Ottawa, Ontario 613-746-4413 you have on hand. Super -Strip gives you 128 separate Brantford, Ontario 519-756-2468 five -point terminals in the circuit building matrix and Vancouver, B.C. 604-324-0505 8 power and signal distribution lines-enough Vancouver, B.C. 604-324-6831 Victoria, B.C. 604-385-2411 capacity to build circuits with as many as nine 14 -pin Winnipeg, Manitoba 204-786-1471 DIPS. And when you're done with your hookup, just Armdale, Nova Scotia 902-876-2920 pull it apart-everything's as good as new. Super- Faster and Easier is what we're all about. Strips come with your choice of nickel -silver or gold- plated terminals. Plus an instant -mount backing and A P PRODUCTS quick -removal screws for fast and easy stacking or INCORPORATED racking. Heard enough? Then stop looking and start Box 110 72 Corwin Drive Painesville, OH 44077 cooking with A P Products Super -Strips. (216) 354-2101 TWX: 810-425-2250

36 ETI CANADA-MARCH 1979 Ell Project Electronic Dual Dice

Electronic Dual Dice

A fine excuse to gamble and have some electronic fun too.

IT SEEMS THAT LEDs and games just As is commonly known, positioning or may be strengthened by sticking it naturally go together, and they are red leds behind ruby red plexiglass to some clear plexiglass or even glass. always popular to build and amuse improves the contrast immensely (look Check out your local community news- people with. Half the fun is showing it at calculators). If this material is hard to paper printer, ask for the guy who does off to your friends, the neighbours' get, then here's another suggestion.. the "stripping", buy him a coffee and kids, etc. and this dual dice project Printers use a sheet film material known he'll probably give you more than you should fillthis requirement nicely, as "ruby lith", in huge quantities too, could use in several decades. What he since it can be used with hundreds and they're always throwing it away. thinks of as "used" is quite suitable of board games and gambling passtimes. This material is sturdy enough to make for panel purposes. (No, stripping isn't This must almost classify it as useful! a display panel cover of reasonable size, at all risque!).

FEATURES The operation of this unit is very straightforward to anyone familiar with the normal dice. Two sets of seven leds represent the faces of two dice, and at the push of the "throw" button the electronics decides which pattern of leds to illuminate to provide a "random" dis- play. The second switch has a "fast" and "slow" position. When set to "fast", the display stabilises instantly when the "throw" button is released, while in the "slow" position the display gradually slows to a stop, imitating the rolling of actual dice.

CONSTRUCTION Building the project is quite easy, with or without the pcb, however the pcb definitely makes things easier once it has been made or obtained. We built our unit with the leds mounted on the board, but they could have been mounted remotely if a different display arrangement was desired. ETI CANADA-MARCH 1979 37 COCJ +8 to 12V C5 5V/%2AVR1 C6 p +5V LED2 V LED3 V LED5 LED7 LED8 LED10 LED12 LED14 +5V 1000u 1 100n 91RR4 91RR3 91RR6 18ORR5 < 91RR7 < 91RR8 91RR10 180RR9 E LED1 LED4 LED6 LED9 LED11 LED13 +5V I ofBottom 01 view 6 13 1/4 11 '4 8 IC4 IC4 2 IC4 10 IC4 9 +5V 4 IC3 IC3 8 13 12 IC3 11 2k2R11 S 3/6105 SW2b +5V 125 9 10 12 1013 SW1b. FAST THROW 4k7R1 11 9 813 A1/6 105 11 9 811 A1/6 IC5 C4 THROW 110.1 SLOW 1/6 IC5 SLOW 1 IN B QB IC1 7492 QC QD INQB B IC2 7492 QC QD +1 1000u 22kR12 2N2646Q1 b2 IC4IC3 74087400 RO1 6 R027 RO16 R02 7 100nC2 150RIR13 b1 100RR14 IC1,Connections 2 pin 5,10, andnot and shown: IC3, IC3, 4, 4, 5 5pin pm 14 / to ground+5V IC5 7404 countertheSupposingThe workings best -display place ofthere thesection, to isdual astart continuous specificallydice understanding is with streamIC1. the fromtically,each the although last stage its of input IC1. pulsesHence,IC2 comeevery and its leds are connectedHOW iden-is IT WORKS equal in the final outcome. reducingonenoise on the the randomness. power supplyWith line SW1 from die circuit in theaffecting "slow" position, the other, theof beingpulses 7492 will being count fed upwards, into pin the1 "IN count B", available in binary (in form on basethen,timeIC2 IC1sixIC1 increases counter, ticksand 2 over togetherby with one from very count. form 110 odd Ina to 2a 000, digitsense operatesoscillatorthe"throw" pulses as buttoncome follows: fromdepressed, C2 thecharges "relaxation" the up circuitdue involving Ql. With the R3,4,6,7,8,10R1,2RESISTORS 91R PARTS LIST 4k7 adecreasingoutputs die"states".like has QD, 6 significance).possibleThis QC, it does QB displays Naturally, as follows: we would since QD, the counter to cycle through 6 order of Whenintoing sequence. As long as the pulses keep onIC1 coming they the display keeps changing. stop, that's where the C2,denlyvoltageto current while conducts, the feeding through e-b1 somewhat currentjunction R12. throughAt dischargingof a Q1 certain R13,sud- R14R13R12R11R5,9 100R150R22k2k2180R normal110.QC,QB= (Note counting 000, that 011 sequence is missing - but from that's the 001, 010, 100, 101, stops"throw"rapidly apparently forbutton the eye is randomly. released to follow. the When display the reason Nowacrossand hence the it, cycle as making Q1 starts quickly a over.short turns voltage off again. pulse C3C2ClCAPACITORS 22u/16V220p100n electrolytic thisanjust additional IChow which the 7492is not counts.used.) ThereThe is gates also of IC3 and IC4 combine 1 bit binary counter in oscillator,displayIC1's stops.was to With avoid SW1 the probleminThe the of output, rather thanfor a separate IC2 counting off "fast" theareleased, voltage "atC3 the slowly top" charges, of R12,highThis gradu-reducing oscillator operates normally at rate. However when SW2 rate is SEMICONDUCTORSC6C4,5IC1,2 7492100n1000u/16V electr 000Noticetothe form outputs through that dice asof displays toIC1the 110, counterto turn the for on countsdieeach the display 7digit. from leds sectionsed,loopposition, the topulses of act IC5and as willwhich thean come oscillator."throw" are fromconnected button Thisthe three runspress- in a at display,charges.uallyally toslow The a stop. theoverall pulses, effect and hence the reducing the at which C2 is to grad- Q1VR1IC5IC4IC3 2N26467805740474087400 5V/'/2A importantreads 2, 4, so 6, long 3, 5, as 1. theThe probability order is not of andabout one million pulses per second, hence the display changes too asterminalof ides 8-12VDC,required regulator, by which the whoseTTL is fed ICs. outputinto C5 Thea prov-threeis power5V supply can be any source SW2SW1MISCELLANEOUSLED1-14 DPDTRed, to Slidespring suit return noiseC6 on the power supply line. is supply to reduce any high frequency input smoothing, while addressesSeeKits their for advertisement ofthis dealers. Wire,project IC are sockets, in availablethis issue battery from for connectors Jana. etc. SW18 SW1b LA FAST SW2b _c IMY4 Ft13 glyf AsTo r )0i,eals NV/ - - /' THROW GROUND L. THROW SW2a / C6 + SUPPLY co COMOVIEVI1 rvAoni ',I.. IMP AMP IMP II a I' AP omnitronix -- 18 ltd.' Specially Imported from England! FREE LITERATURE Visit your local distributor or drop us Electronic Projects a line on your letterhead. for Beginners

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This unit demonstrates the principles of generating a sequence of analogvoltages of varying time lengths, for use with music synthesizers or industrial and other controls.

7 3

1 2 2 8 2 11 2 11 2 2 11 2 1:508110111.

1 1 9 1 1 1 10

r4

3 7 3 3 7 8 2 8 8 2 2 I 2 0 C MAIM 11 1 1 1

10 0 10 10 10 11 12 4.1: 11.5

1- $ Si/rtGLf fall NOLO 2 14 157d

2 1. 11 MIA

0 Dt.144. CH 2 - OK* OWN 1 11

SEQUENCE LENGTH WOE SP11 O CQN TROt

OsAesel-Ned arsL.C.4frac

ONE OF THE accessories most requested for use with a synthesizer is a sequencer, which allows a rhythm to be played using spare VCO's and envelope generators,etc.,inthe SPECIFICATIONS synthesizer while playing the melody with the keyboard. In addition, a number of other Number of steps 2 - 16 single output problems arise in other areas, such 2 -8 dual output as industrial controls, were a sequence of analog voltages would be useful. Output voltage 0 -5 Volts This unit is capable of replaying up to 16 individual notes at a regular beat Speed 10 ms - 1s per step or up to eight steps where the beat is Output impedance variable as well as the pitch. If a regular <1 Ohm beat is used, two separate channels are Load resistance available, provided the length is limited > 500 Ohms to eight notes or less. Trigger pulse This unit could of course be expan- 2 ms negative pulse ded up to any length of sequence that Power supply 8 - 15 V dc your budget would allow, using the same principles.

ETI CANADA-MARCH 1979 41 ETI Project Ve 0 51 Synthesizer Sequencer (8-15VDC) INPUT 52 Cl10, RUN SW3CIV 0-0. +5V 0 15 016 0 '7 0 18 40 19 20 0 21 0 22 0 23 0 24 0 25 0 26 0 27 0 28 0 29 30 +Ve C510n 11--0.0V 13 14 15 12 2 4 3 14 15 12 4 PBI 64 5551C2 3 look 2 4520IC3 4051IC4 4051IC5 STEPSINGLE.' OV 7 4 3 11 10 9 6 11 A 10 B C TOinN 6 53 SW 12 04 OV OUTPUTTRIGGERO eac.SW2/1 5 +Ve 11 10kR5 R6 IC7 11 10 9 C8 PB2 06 LED1 7 4051 C6 3 330p +Ve ve 41-4e LED2 14 15 2 4 47 2 CA313UICO 49 Cri.NNEL 2 OUTPUT OV SW4 01312 31 32 33 34 135 136 137 /38 SW2 2 S 10kR21 10kR3 R8 +Ve R911 040 R19 CO 10 IC7/4 1M 9 1MC610n TOTHENOTES: OV FOLLOWING BUT NOT SHOWN. PINS ARE CONNECTED soOUTPUTCHANNEL 1 0v C7 14 LE D3 39 40 41 42 43 44 45 46 LED1O PIN 6,7,87.87,81,8 IC6IC5IC4IC3 1n0 R1010k 1kR11 lkR18 TOTHEPIN +Ve7 FOLLOWING BUT NOT SHOWN. PINS ARE CONNECTED IC7 Fig. 1. Circuit diagram of the sequencer. OV. PIN 16143.69,10,15,16 IC7IC6ICSIC4IC3 'SEE TEXT OV controlled by IC2 which is a 555 Thetimer. sweep It timeHOW of the sequencer IT WORKS is bufferbetweenIC4multiplexers IC9(RV3 the corresponds outputsto are RVIO) andto the IC8 output to that of of active, is the connectionopen and the RV18areoutputwhichclocks whichhowever givesIC3, athehave four is in a -bit fixedfour -bit supply binary Thevoltage form. individualset levels on the in thepotentiometers sequence RV3 to 16 steps required. The binary counter, bitssequenceandpositionIC5 of the IC7.(RV11 is binary onlyindicator IC6 to eight code decodesRV18). stepsLED's and drives Inlong.the is this donelower theControl mode eightby three IC6 the of sequence length and the ThisacrosssynthesizertoICI aboutreduces andthem. the 3.8 One otherthe VCOV bysiderange side thecan is israngeat overbe variable+5 varied, Vwhichcontrol as fromset making the RV2.by OV andbyoutputThe LED'sIC7/2 2upper which plus andindicating bit the are isIC7/3 normal theinverted row which output indicators. by drivecolumn IC7/1 are LED'sbuffered and is active.this 1 selectedeighttoset-up -inputthe easier.inputinputs depending of IC4 and on IC5 the Thesewhich binary 16 are output voltages are connected analogue multiplexers, the thelengthselector.to SW5 supply selected, whichWhen rail. When thethe sequencervoltage the next on step R9The occurs,is near output of IC6 is also connected is the sequence length is on the IC8fromallowenablecode presented IC4full line 16and input IC5 to the operation.both control are buffered inputs.The outputs The by and IC9 is usedto as a control line to prevent loading the zero).sequence,resetsthis pulsevoltage onto(provided falls one to inputzero the andotherof IC7/4, C7 input connects which is on IC3 back to the start of the identicalconnectedselectedpotentiometers. alternately outputs. In and the their dual outputsmodeIn the both are single mode the multiplexers are so that both buffers have lengthsslightresistorthe delay row of R8 8 toorandand give16 capacitor notes correct are operation selected.C6 provide whenThe asecond input to IC7/4 determines is selected by SW4. The

Fig. 2. Printed circuit layout. Full size 140 x 70 mm. Fig. 3. Front panel artwork. See Fig. 7 for dimensions. ETI Project

25 23 47 17 15 33 31 2 43 1 +12V 4816 18 32 34

51 1 I +12V C +1 c0 52 ka INPUT IC4 OV ... C2 0") 0 CO + CN 01 IN N 53 C 9 ct. j...R9 +5v cvl NII 10 ...... cR J....) Mto R19 m7C-38 C:) C7 0- OV

N c c -I 1- t-ao 2aW 49 CO 6'1)1 < R11

11 1 111111 CHANNEL 1 13 5 12 7 14 6 8 OUTPUT Fig. 4. Component overlay of the sequencer.

DESIGN FEATURES The front panel can be assembled as The mechanical construction we have shown in Fig.5 and interwired to the PC used need not be followed if the unit When initially looking at this unit we board using the numbers on the wires has to fit into an existing space and had to decide between two different for reference. Due to the large number none of the wiring is critical as regards approaches. The first, which is presented of wiresitisrecommended that length or layout. We didn't use a power here, is to use a heap of potentiometers 'rainbow' cable be used for neatness. switch as the module was used on the on which the individual voltages are When connecting the LED's note that synthesizer power supply. manually set up and a large multiplexer the shorter lead or the lead nearest the to select the potentiometers sequentially. notch or flat on the body is the negative The output of the unit is in the range This system is economical up to side (cathode). of OV to +5V if R19 and R20 are not about sixteen steps. Beyond this, the cost of the hardware, i.e. potentiometers, knobs, panel space, etc., is far more than the cost of the electronics involved. PARTS LIST In the second system, the tune is entered 'live' through the keyboard RESISTORS (all 4z W 5%) SEMICONDUCTORS and the individual notes, the key 78L05 or 7805 regulator depression times, and the intervals R1 100k IC1 R2,3 10k IC2 555 timer between notes are sorted in a memory. R4 100k IC3 4520 dual binary counter Long strings of notes or more could 10k IC4 - IC6 4051 8 -bit data selector R5 4001 quad 2 -input NOR be stored in this way and then replayed R6,7 1k IC7 IC8, 9 CA3130 op -amp as a rhythm (ormelody!). R8,9 1M This system is obviously much more R10 10k LED1 - LED10 Red LED with mounting R11-R18 1k clip flexible but it is more expensive and R19,20 see text complex if a short sequence is all that R21,22 10k MISCELLANEOUS is required. However, cost does not rise POTENTIOMETERS PC board ETI 603 DPDT toggle much for longer lengths. RV1 1M lin rotary SW1, 2 RV2 10k lin rotary SW3, 4 SPDT toggle RV3 - RV18 50k tin rotary SW5 single pole, 8 or 11 CONSTRUCTION position The PC board should be assembled as CAPACITORS PB1, 2 single make pushbuttons Front panel to Fig.7 shown on the overlay diagram (Fig. 4). C1, 2 10µ 16V electro Bracket to Fig. 6 The CMOS IC's should be installed last C3, 4 1110 16V electro The pcb for this project is available from C5,6 10n polyester Spectrum Electronics, 38 Audubon St., S. and the power supply pins (7 and 14 C7 1 n0 polyester Hamilton Ontario L8J 1J7 and from or 8 and 16) should be soldered first to C8, 9 330p ceramic B & R Electronics, PO Box 6326F, allow the internal protection diodes to Hamilton L9C 6L9. work. 44 ETI CANADA-MARCH 1979 Synthesizer Sequencer

LEO10 LED9 LED8 LED6 LED5 POLARITY LED7 LED4 LED3 OF LED 3--11 46 45 44 43 42 41 40 39

POLARITY* OF LED 1.2 (74 8S 37S 36S 35S 34S 33S 32S 3

LED2

LED1

23 5S 35 34S 34 33S

12 33 47 11 32S 48 13 37 37S 32 38 31S 31 38S

CHANNEL 2 14 RANGE RESET SINGLE HOLD SPEED OUTPUT MODE SEQUENCE LENGTH STEP NOTES: WIRES 315 TO 38S GO BETWEEN SWITCH AND LEDS.

Fig. 5. Wiring of the front panel.

Fig. 6. Details of the small bracket which Fig. 7. Details of the front panel metalwork. supports the PC board.

5 55 60 used. If a higher voltage is required the value of R19 and R20 can be calculated as follows, (V 2 HOLES 3.5mrn R19,20 = 1 I x 10000 ohms FOLD 90°

INTERCONNECTION MATERIAL: 1.25mm AL. While most synthesizers use some form of voltage control scheme for their oscillators and filters,it would be 2 HOLES 10rnrn wise to find out exactly the require- 0 ments and capabilities of your parti- cular unit before embarking upon, or 50 modifying this project.

0 13 HOLES 6.5mm DIA. Q 2 HOLES 7.5mm DIA.

12) 19 HOLES 10 mm DIA. MATERIAL 1.25 mm ALUM.

ETI CANADA-MARCH 1979 45 Getting Into Video Video Tape and Accessories

Steve Rimmer discusses add-ons in Part 4 of Getting Into Video.

VIDEO TAPES . A NEW MYSTERY The "secret" of video recording is the tape: it is only with the formulation of a recording medium capable of surviving the rigors of the helical scan tape transport and at the same time record and play back the "difficult" video signals involvedthatallofthe technology of video tape recording is possible. Whereas with audio recording the tape can be considered to be secondary, "any of tape that'll fit on th' machine'll do fine", with video the choice of what tape to use is of the utmost importance. First of all, the tape must be video tape. This statement is not as erudite as it sounds. One of thetemptationswhich sooner or later inspires most home experimenters is the bonanza of the data processing industry; computer tape. Largelymadeobsoleteby narrower gauge tape and disc stroage need not be attached nearly as firmly to The third hassle with video tape is systems, "fantastic, origi nally cost $300 the backing material as is necessary that all tapes are not created equal. a roll" one inch tape can often be had for with video tape. The rotating head of a Each machine is designed to use a less than the price of the reel it comes VTR would very quickly grind up the specific type of tape, and very often the on. However, if you do manage to get it oxide, and in so doing, wear itself down tapes suppliedfor machines ofa respooled and runitthrough your to a frazzle. different manufacture will not work machineitwill munch your three There are several other manifesta- satisfactorily. They probably will not hundred buck video head in less than an tions of one inch tape around, data harm your VTR; they simply will not recording tape, audio yield a picture. This can be rather hour, . . . besides producing a very (instrument) disappointing picture, if any at all. mastering tape and so on, none of confusing, as sound and sync will The problem with computer tape is which are usually suitable for video usually come out just fine. that, just as is video tape, it has been applications. This, in effect, rules out The difference between tapesis formulatedespeciallyforits buying "bargain" surplus tapes, largely in the thickness of the backing application.Dataprocessingtape because there is no way to figure out material. It seems that thick tapes used driveshavestationaryheads and what an unmarked reel of tape was on thin tape machines cannot get vacuum tape guides such that the head originallyintendedfor,shortof enough surface area over the head to and tape are always very slightly imperiling your VTR. When you buy effect a reasonable transfer of energy. separated, and do not actually come in video tape, do so from some party The last point regarding tape is its contactwithoneanother.Thus, dealing specifically in video products, care and housing: it is easily damaged computer tape can be much more and make sure that it isclearlydesigned by extremes of heat, cold and humidity. abrasive, and the recording surface "video" tape. Therecordingsurface may be 46 ETI CANADA-MARCH 1979 Video Tape and Accessories

degraded by any one of a number of Video signals can also be obtained you may want an adapter to mix the two agents, the most common of which is from several other sources. One of channels down to one). fingerprints. It shou Id not be exposed to these is called the "tele-cine chain" and There are further refinements to the dust, which can get ground into the is used to produce television pictures system, such as effects generators, oxide andlater act to abrade the from motion picture film or from still keys, video feedback loops, sync time recording head. To this end, it should slides. In its simplest form, thetele-cine base comparator -correctors, editing never be left threaded through the chain consists merely of a projector systems, and so forth which also fall machine when not in use, wherein it is coupled to a camera. However, for the into the scope of the expanding video susceptible to all sorts of foreign matter home experimenter who may not wish system, but are a bit complicated to get floating around.It should always be to tie up a camera in such a system, into here. When you get the system as it storedinitsbox away from the similar results can be obtained with a stands now, together and working, aforementioned bad influences. Even flying spot scanner. In this circuit, a these refinements can be added and the the boxes warrant some consideration: small cathode ray tube with a blank versatility of the whole mess expanded the blue and white plastic containers television rasterisplaced before a still further. supplied with 3M tapes, (which can photo tube. A slideisinterposed actually be sealed when not in use, may between the two. As the beam of the be decidely better than the cardboard CRT scans and excites the phosphor on STAYIN' ALIVE containersusedbyothertape its screen, it produces, at any given Despite the plethora of meters, belts, manufacturers, or the plastic ones that instant, a single spot of light, which is pulleys, gears, solenoids, relays and Sony makes (which are not sealable), applied to the photo tube and converted internal whizbangs that make your VTR especially if your tapes are to be stored back into an electrical impulse. The go, the routine maintenance which you in a particularly dusty environment. amplitude of the impulse is directly must lavish upon it is relatively minimal Lastly, make sure that the reels that proportional to the intensity of the light and, in fact, will probably not prove hold your video tapes are not warped, falling on the tube's photo -cathode. much more troublesome than the as this may fray the edges of the tape, The intensity of the light, in turn, is maintenance of an audio recorder. Still, eventually rendering it unusable. governed by the density of the slide at it must be observed carefully in orderto that particular point where the light keep your machine operating at peak passes through it. Thus, moving beam efficiency. ACCESSORIES scans the slide and produces, at the Thefirstconcernof VTR No systemwouldbecomplete photo tube, a video signal. Sync signals maintenance is the care of the video without the need for some accessories are added afterwards. head. Considering what this part is to render it incomplete as it stands. With The flying spot scanner can also be subjectedto,itisnotdifficultto the VTR, the range of accessories is adapted for use with a movie projector understand that its operating lifeis limited only by the size of the user's by replacing the projector's bulb with much shorter than that of a typical workshop. Just to get your imagination the photo -tube and focusing the lens on audio head. One manufacturer, for going, here is a brief rundown of some the CRT. In order to get the film to come instance, cites a pessimistic 500 hours of the other things you can hook into a out the right way 'round,it may be between head changes. However, the video system to expand its versatility. I necessary to reverse the polarity of the life of the head is largely determined by hope to elaborate on them in future CRT's horizontal yoke so as to make the hcw it is used and maintained. writings. scan go backwards. When the head is whizzing around The most obvious departure from Severalcircuitsforflyingspot during normal operation it develops a simply recording and playing back scanners have been published in ham cushion of air between itself and the broadcasted signal is to generate some radio magazines. An afternoon in the tape, several molecules thick, which of your own, and the medium which first archives of your local library should negates the abrasive characteristics of comes to mind is the television camera. produce one or two good designs. the tape surface. This cushion, however A simple vidicon unit will suffice quite Your VTR can record video from any cannot be maintained when the head is nicely, and these can occasionally be source, including some of the more travelling at speedssubstantially found surplus for less than a hundred recentlyintroducedtelevision - slower than those at which it is intended dollars. They can be built by the home associated devices, such as TV to run when in normal use. Thus, the experimenter with the ubiquitous "well typewriters,bio-feedback machines major part of head wear takes place stocked junk d rawer" foreven less. With and the like. "Pong" afficionados can when the headisaccelerating or a TV camera it becomes possible to even use the VTR torecord their decelerating, conditions which occur produce one's own shows and to matches and analyze their strategies. when the tape is started and stopped. experiment with the television medium Aside from things to feed into the Thus, multiple short recordings should as a tool for creativity. video, you will also want to put some be avoided in the interest of prolonging The capabilitiesoftheresulting sound on the tape and this is done in the head life. entity, the telvision studio (even if it is conventional manner. Most electronics Head lifeisalso reduced by only your living room), can be further experimenters will be familiar with the producing "stop action" pictures, that enhanced by the addition of a second various sound components now is, by turning off the reel drive motors camera and a method of selecting available; mixers, equalizers, while the head is spinning and manually between the two. This can be a simple synthesizers, and soforth,and a tightening the tape until a single frame toggle switch,butitcan also be detailed description of whar can be is displayed on the screen. expanded into effects boards which done in this area will probably not be The head must be cleaned produce split screens, wipes, fades, necessary. Suffice it to say that any frequently. For complete details of how dissolves and allthe other various audio component that is compatible and how often this procedure is to be devices familiar to television viewers. with your stereo system should work carried out, it is advisable to consult the The resulting "switcher-fader", as it is equally as well with your VTR (except literature of the manufacturer of your called, is a topic all in itself. that the VTR of course, monaural: machine, as different types of heads ETI CANADA-MARCH 1979 47 Getting Into Video

require different cleaning techniques. consult the manual for your machine currentavailabilityofequipment. The head is usually cleaned with a for the details of this procedure. Usually Hopefully, this article provided enough camel's hairbrush, an aerosol spray ora alcohol on a Q Tip or a clean camel's information and ideas to get you started Tip soaked in alcohol or a special hair brush is used. in this field; there are several good cleaning fluid. In those cases where a If your machine uses slip rings to books on the subject kicking around liquid cleaning agent is used, avoid transfer video signals to and from the and,perhaps,iftheresponseis applying an excessive amount such spinning head, your manual will also favorable, there will be further video that some of it drips into the workingsof provide instructions on the cleaning of articles appearing in ETI in the near the machine. Many of the synthetic these parts. future. rubber and plastic parts used in VTRs Stay tuned. are soluble in the chemicals commonly found in some head cleaning solutions. TRAI LER With thanks, for help with the machines The tape guides, pinch rollers, tape Video Tape Recorders are a and the series, BarryKushin at Philips, gates and the erase, audio and control fascinating and complex subject, one Emil Adamyk at Comad Communica- trackheadsalsorequireperiodic wellsuitedtothe advanced tions, Bob McEwen at McEwen Photo cleaning. Once again,itisbest to experimenter,especiallywiththe and Joy.

Needle Pulse Variable Zener Capacitor Substitution ALARMS Stable Linear Sawtooth Zener Boosting of Regulators FM Tuner Station Electronic Capacitor Zener High Power Current Flow Speeding Up Darlmgtons Basic Alarm Disco Cue Photo Intruder Alarm Noise Electronic Fuse Shutter Saver Intruder Alarm Pink Better Fuse Thyristor Sensitivity Photo Electric Relay Simple Relaxation Regulator & Fuse FLASHERS Sound Operated Flash Low Temperature Lights out Triangle with independent slope Fast Acting Strength Tester Temperature Sensor Exponential SCR Crowbar Dancing Lights Logic Noise Immunity Coolant level Widerange Multivibrator Voltage Polarity Low Frequency Strobe Water Level Multiple Waveform Ni CAD Discharge Current Limiting Hasher TIPS Electronic Lock Linear Sweep Ultra Simple Car Battery Watchdog Step Frequency Identifying 74 Series Simple Car Alarm Beeper TEST Supply Pins Simple Lock 7400 Siren POWER CONTROL Soldering ICs Simple Siren Diode Checker Tinning With Solder Wick Ship Siren GO NO GO Diode Tester LOP Mains Control PCB Stencils AMPLIFIERS & Two Tone Zener Check Floodlamp Control Front Panel Finish Toy Siren GOND GO Transistor Tester Zero Crossing Sync DIL Drilling PREAMPLIFIERS Kojak. Startrek Quick JFET Test Train Controller Fluorescent Starting Current Gain Tester High Input impedance Sound Effects Low Differential Thermostat Avoiding Insulated Heat Sinks Sound Effects Basic Transistor Tester Simple Temperature Control TTL Mains Interface High Impedance Buffer Simple Transistor SCR Low Output Impedance Full Wave SCR Control Boost Your Mains FILTERS SCR Tester Low Meters O Low Frequency Extender Crystal Check High Voltage Electrolytics Bandpass Crystal Checker AUTOMOBILE Transistor Identification Virtual Earth Preamp Good Bad Battery Tester IC Tape Head Preamp Low 8 High Pass Template & Heat Sink for Simple Stereo Tape Player Rejection Notch Battery Tester Brake Lamp Failure Power Transistors z Bandpass Op -Amp Tester Courtesy Light Delay Transistor Socket 2 5 Watt 20 Watt Slave Cartridge EC 5i Rumble Op -Amp Checker Simple Hazard Light Solder Flow Problems 10 Watt Hum Stopper '.:heap Logic Probe Light Extender & Reminder Odd Resistor Values cn Loudspeaker Microphone Tape Hiss Reduction tkudible TTL Probe Four Way Flasher Resistors in parallel Voltage Controlled Amp Simple Crossover Audible Slow Pulses Headlamp Dipper CMOS DIL Handling Wide Band Amplifier Logic Probe Wiper Delay Identifying Surplus ICS Logic Analyser Suppressed Zero Voltmeter Extending Battery Life Video Power Amp I and 0 Display Probe Broadband Amp DIGITAL Rev Counter Tachometer Battery Snaps Simple High Impedance Auxiliary Battery Power Supply or Battery Thermometer Voltmeter Battery Checking S Heads or Tails Audio/RF Tracer Muck Remover SIGNAL PROCESSORS Binary Calculator Thermocouple Thermometer DETECTORS & Transformers in reverse Voltmeter Fuzz Box Metering Stabilised supplies COMPARATORS Loudspeaker Checking Seven Segment to Decimal Simple Frequency Meter Guitar Fuzz Die Improving UJT Linearity Fuzz Box Random Binary Peak Detect & Hold Signal Tracer Waa Waa CMOS Die TIMERS & DELAYS Window Detector Crystal Earpieces Disco Autofade Multiplexer Hints Peak Program Cheap Varicaps Simple Autofade Learning Memory Positive Peak Zener Lifts Capacitor Rating Information Transfer CMOS Clock Low Standby Drain Reaction Comparator Optical Pulse Conditioner 741 Timer DATA TV Sound Pickoff Self Triggering Timer POWER SUPPLIES Pulse Timer RADIO FREQUENCY Cracklefree Potentiometer 741 Op -Amp Data Voltage to Frequency Pulse Delay Constant Voitage Controlled Monostable BC 107-109 Data Sine to Square Wave Temperature Stable Crystal Marker BC 177-179 Data Precision AC to DC Sequential Relays Constant Door Chime Delay 100 kHz Marker CMOS & TTL Data Voltage Processor Voltage Controlled RF Voltmeter 2N3055 Data Universal Meter Precision Voltage Divider RF Detector MJ2955 Dat Double Precision Dual Polarity SWITCHING LED RF Indicator Bipolar Data Tables Fast Halt Wave Simple Balanced RE Amplifier Protection Bipolar FETs Rectifiers Simple Chopper Voltage Divider Touch Triggered Bistable FETRadio Diodes Pinouts Zener Misc Noise Rejecting SCR Trigger Low Regulated Touch Sensitive Switch Op -Amp Radio Phase Shifter Short Circuit Protected Electronic Switch AN IDEAS BOOK Simple TTL Supply Sound Operated 2 Way MISCELLANEA SIGNAL GENERATORS ZN414 Supply SPST Switch Flip Flop FOR Stable Reference Two Signals on one Wire Simple Transformerless Invertor Phase Locked Loop EXPERIMENTS Variable Duty cycle DC to DC AC Touch Doorbell Fast Edge Voltage Multiplier INDICATORS Phase Lock Control SEND FET Automobile Convertor Audio Mixer $5.00 Improved Multivibrator Shaver Adaptor Line -o -Light Virtual Earth Mixer Variable Duty cycle DC -DC 3 Step Level Plop Eliminator To ETI Circuits, Stable R C High Voltage From Battery Light Level Loudspeaker Protection ETI Magazine, Cheap (CMOS) Variable ve or -ve output Bargraph Display Digital Capacitance Probe Simple TTL XTAL Simple Fuse Failure Digital Tape Recorder Adaptor,Unit Six, 25 Overlea Uncritical XTAL t 2V from Battery Charger Blown Fuse Breakdown Diode SubstitutionBlvd., Toronto, Pulse Bucket Regulator Back Up Lamp Uual Function Charger Zero Crossing Adjusting Zener Voltage DC Lamp Failure Dual Mode Amp Ontario. M4H 1B1 Simple Pulse

48 Five books on page 69. ETI CANADA-MARCH 1979 Home Climate Control Principles

The concepts are straightforward, and it's something you can play with. From Stephen MacLellan, Senior Engineer with Canadian Thermostats and Controls.

During the last few decades we have evaluated as a viable substitute foroil in ooserved around them. They used become more aware of the demands thermalelectricpower generating common sense and basic observations that modern society places on energy plants,andfor domesticheating of natural phenomena when they built reserves. As our desire for a better way purposes. Researchers are hard at work their homes and irrigation systems. of life sees fulfilment in more television exploringsolar energy conversion Through thecenturies wehave and radioentertainment, improved systems, wind turbines, tidal power somehow managed to lose that ability. telephone services, homes with central projects,and fusionreactors. Maybe we have allowed ourselves to be heating and air conditioning, Engineers are pushing our technology caughtupin thewondersof automobiles with luxurious options, to the limit to develop more efficient technology. Whatever the reason, it is and easy access by air travel to most motors and generators, and to reduce time we all take a good look around us, parts of the world, we overlook our the amount of power consumed by the and observe this world we live in. It hasa increasing consumption of energy. The equipment thatisessential in our lot of surprises in store for us. If we were very way of life we have come to take for society (computers, communication to take the basic knowledge and granted has a pretty big price tag, called systems, and transportation systems). common sense those ancestors of ours energy, and we are only just starting to Electronics isplayinganever used a couple of thousand years ago, be able to weigh the things we want increasingroleofimportancein and combine it with the technology of against an energy value that is going up society. Computers and communica- today, we would have an interesting with increasing demand. tions are obvious areas where this is so. world. Can you imagine what kind of Withrecentfuelshortages The not so obvious areas are just as world we can have if we add our modern experienced in the Western world, we significant. Modern medicine relies scientific knowledge to the other two? have become more aware of conserving heavily on electronics for investigation, Fascinating, isn't it.? energy, by increasing and restricting diagnosis, and treatment. Many The unfortunate factisthat our the price and availability of automobile machineryoperations havebeen society as a whole has learned toaccept fuel, and by increasing the cost of fuel turned over to electronic control, and what is, without asking why it is. Even oil used for domestic heating. The combinations of LASERs and engineersandtechnologistshave additional action taken by government computers fabricate components to generally stopped asking why things to increase taxes on larger cars, and tolerancesthat mechanical are the way they are around us, and yet applying a special tax for automotive air machining can't come close to. What is they are the very people who work in a conditioning, has also helped generally most important inallthisis these vocation the nature of which is to ask to cut down on a percentage of the improvements are actually reducing "WHY?". overall energy consumption. Media ads the amount of energy consumed, yet In this article,I am going to get you to turn down the furnace at night, keep productivity and quality are better. not only to ask WHY, but WHAT, HOW your car tunedup,shutoffthe The "key" to energy conservation is and most importantly, WHY NOT. I am refrigerator and air conditioner while intelligentuseof science and going to do this by appealing to away, and turn off unused lighting has technology. When we accomplish this, something that in this day and age is had it's effect as well. We have managed we will open wide the doors to a very very important to all of us, ourspending to reduce a portion of the energy promising future. money. wastage that was occurring. We have also become aware that there is a lot CONCEPTS OF THERMAL CONSERVATION more that we can still do to reduce and ENERGY CONTROL The field of energy conservation is possibly eliminate unnecessary energy vast, virtually everything you can think losses. ANCIENT CIVILIZATIONS MADE use of consumes energy in some way, and of the materials at hand to help them conservation of that energy saves each At present, many approaches are harness the sun, wind and rain to of us real money. being taken to preserve our energy improve their environment. They had The way in which we come closest to reserves, as well as developing new no outside help, or magic ircantations, energy conservation is our own home energy resources. Coal is being re- they simply put into use what they heating and cooling system. Most ETI CANADA-MARCH 1979 49 people think of a furnace as some sort of 90° (32°C, Istill tend to think in F°). As related when we try to heat and cool our big black box hidden away somewhere for wind and water, ask anyone who has homes to any degree of comfort. The in the dingy depths of the basement, lived on the coasts about that.I've whole trick here is to look at the heating amongst the spiders and other bugs. In walkedalongtheshoresofSt. and cooling problems of a home as a other words,people are generally Margaret's Bay, near Halifax, with my "thermal system". Being more aware of uninformed abouttheirheating favoriteladyon a day withthe the inter -related effects of temperature, systems. This situation isn't helped by temperature in the mid seventies, and humidity and wind is primarily a matter theserviceindustryeither. For actually felt cool, while friends a few of experience, but most of us know that whatever reasons, servicemen have miles away in downtown Halifax were wefeelcomfortable whenthe managed to terrify more housewives complaining about the heat. temperature is around 70°, the with thoughts of a furnace gone berserk Temperature and humidity were the humidity somewhere around 50%, and than Alfred Hitchcock ever dreamed of same, but while we were exposed to a a gentle circulation of air. These values with his movies. gentle sea breeze, our friends were willvary dependingonindividual "becalmed" as the saying goes. In the tastes, but it is the combination of the winter this combination of wind and three in the right ratios that will do the FEELING HEAT humidity can make life miserable. For job. My intention is to give a working I have already made a very brief those of us with fond memories of reference to the use of the sun, wind, sailing out of Halifax Harbour on a understanding of the concepts of ther- and rain in making a domicile more winter dawn, trying to get warm again is mal energy control, and I am going to habitable. We all know how warm the an exercise in frustration. That cold sea do that by introducing the reader to the sun can be, even on a cold winter day. aircut through the RCN weather "tools of the trade", and then going I've been living in Montreal for the past jackets and into your bones, and there it through the application of these tools few years, and I found out that it can get stayed. It isn't only temperature that we on a conventional home heating and cool here in the wi nter. There have been feel, it is the combinatin of temperature, cooling system. days that not even a Brass Monkey humidity and wind that gives us a would go outside, yet the sun shining comfortable feeling. .TOOLS through the livingroom window has The funny thing is, very few of us pushed the room temperature up over consider these three phenomena as In thermal energy systems, the "tools of the trade" are not something to hold in awe, nor is thereany"black magic"or two hundred years of study before you are allowed to gaze upon the OFF/ON switch. All that is required is common sense, a little reading, and a lot of work. Risking accusations of becoming technical, lets look at each of the tools in turn to find out what they are, how they differ, and how and why they are applied in the system. These "tools" are the temperature sensor, the temperature control, the unit being controlled(the furnace orair conditioner), the environment being -r controlled (the interior of a home or a greenhouse), and the thermal feedback loop. Together they form a thermal controlsystem,andunlesseach .., . individual part is considered in context with the entire system, reductions in operating performance and efficiency (t) ( 3) result. THERMAL SENSORS The temperature sensor is probably the most improperly used part of a thermal system. They can be as basic as a bi-metal switch, or as exotic as a Molybdenum/Rhenium sheathed Platinum/Rhodium thermocouple (used for temperature measurements up to 30000F). Each temperature sensor has an application and temperature Fig.1. In a conventional home heating system, hot air, heated by the furnace (1), is forced through the hot air ducts (2), and dissipates throughout the home, with some of the heat range it is best suited for. Table 1 gives being lost through the roof and outside walls (as indicated by the small arrows). As the air a brief listing of some temperature cools down, it sinks towards the floor and is circulated back to the furnace via the cold sensor types broken into three main air return ducts (3). categories, with a general description A surprising amount of hot air is actually trapped into the attic, and represents even in well insulated homes a fair portion of the heating costs lost since it is not circulated of the characteristics and application downwards. areas for each type.

50 ETI CANADA-MARCH 1979 Home Climate Control Principles

Some thermalsensorsarealso a visual display of the temperature THE "CONTROLLEE" controls. Primarily this refers to the bi- being sensed. Electronic controls of metallic types used for heating and this nature are inherently stable, very The unit being controlled is almost coolingthermostatsinhome accurate,and can bemadeto sel'-explanatory. The reason I say environments,where theydirectly compensateforsensoragingor almost is that since these units are so controlelectrical power applied to variation. They can also be made to be basic, a lot of people overlook them with heating elements, furnaces, and air programmable, varying termperature a simple observation that they either conditioners. The significant settings with time, or sensing several work or they don't. Although it is true advantage with these units are their low independent sensors to maintain large that furnace either works or it doesn't, it cost and simplicity, and with the bi- areasorseveralsmallareasat is also true that a furnace can work metal spring types described independently set temperatures. efficiently,orinefficiently, andstill previouslyinthisarticle,offer work. The point I am trying togetat here reasonably high sensitivity and low Their capabilities and applications is simply that any device used for hysteresis allowing relatively stable arelimitedonly by the designers heating or cooling purposes has an temperaturecontrolatanygiven imagination, but like any good thing of efficient or inefficient way of being setting.However they do have a its nature, the more you want itto do, the used, and sometimes inefficient use relatively long thermal time constant more expensive it is, and unless there can make a unit look incapable of doing (the timeit takes to respond to a are individuals out there who are into the job required ofit.Heating and temperature change) and as a result gadgetry, and will gladly pay a few cooling units(air conditioners and can have a fairly long settling time (the thousand dollars for a temperature furnaces) are rated in BTU's (British time that is required for the area being control that will control the stereo Thermal Units, a measure of the heat controlled to stabilize at the desired system throughout the home as well as required to raise one pound of water temperature).Theothertypesof maintainingtemperature,humidity, one degree Farenheit, which is 251.98 sensorsrequire some formof and air velocity in every room, and keep Calories). This figure relates to the electronic control circuitry, but offer tabs on where junior is, most electronic temperature change capacity the unit faster thermal response times and more temperature controls are really a little has, and is usually given in unitsper stable operation while sacrificing the expensive and unnecessary for home hour. What this means is thatif a significant cost advantage that bi-metal environmental systems. furnace has a BTU rating of 25,000 per devices offer. For most residentialapplications however,thebi-metaldevices presently available, if properly utilized, willadequately handle the requirements. Temperature controls are devices which interface between a sensor and the heating or cooling plant. One basic typeofdevice which I havenot mentioned previously is, like bi-metal devices,inherently a temperature sensor and control. This is the Bourdon tube and expansion bellows which are usually incorporated with an electrical switch and finds its primary uses as the lk temperature control in a refigerator. .111. - ---aft Although these units are fairly sensitive szliz to temperature variations, they are also Sa -- - more subject to mechanical failure problems since the active material is a pressurised gas within the tube that is Subjected to bends and flexing during installation and maintenance periods. The tube material is usually copper, and will crystalize, becoming pourous,or actually break, if flexed too sharply or too often. For this reason, its use is restrictedto minimum mantainance systems, where thetube, once installed, is not subject to flexingor mechanical damage. Othertemperaturecontrolsare electronicdeviceswhichactively transform the sensor characteristic Fig. 2. When an air conditioning system is added toa conventional heating system, the from a semi -linear to linear response, cooling coils are usually installed in the portion of the existing heatingducts that are used to supply hot air to the home. The cooling coil, (4), lowers thetemperature ofthe air flow and provide means to allow adjustment provided by the furnace fans (1), and is forted our into theroom. But since the air is cool to a desired control temperature and it tends to stay near the floor, and is drawn back into the furnace'scold air duct (3), and causing an output device to turn on or recirculated before significant cooling of the room takes place, whichresults in a layer of warmer air remaining at the ceiling. Item (5)is the heat exchanger unit of the basic off, or convert the sensors readings into central air conditioning in popular use today. ETI CANADA-MARCH 1979 51 hour, and the rate of heat loss of the lower capacity. Most residential LOBSTERS AND DUCTS system it is used in is a little less than heating systems areinstalledwith Although we have actually started 25,000 BTU's per hour, then the furnace furnaces or electric heating that has theenvironmentbeing been matched to the requirements of discussing will just barely be able to maintain controlled, the paragraph above temperature stability. If however, the thatbasic home type, and certain mentions the environment as an aspect sytem losses are greater than 25,000 assumptions are made by the installer of the heating and cooling plants. In as to the volume being heated, and the BTU's per hour, the temperature will reality,these twoportionsofthe decrease to a value considerably below rate of heat loss through outside walls surfaces when standard thermal system are very much inter -re- therequiredamount,giving the androof lated, since it is not just the capacity of impression that the furnaceis not insulation practices are used. In many the heating or cooling plant, but how working. In fact, the furnace is working, cases however, the basic home type is that capacity is applied to the system or but does not have enough output, since "modified" over a period of time environment in question. How many the requirements of the system are recreation room, enclosed garage, a times have you been sitting in a room, above the capacity of the furnace. Even second floor, etc), and these changes feet freezing, while from the waist up if the requirements of the system equal drastically effect the heating load that you feel like a well done lobster? The that of the capacity of the furnace, the the furnace "sees", with the end rasult furnace is obviously working well, but system will not be operating effectively, that certain rooms are colder, and other what is wrong is that no attention has since there are additional losses in any rooms are hotterunlesscareful been paid to the natural phenomenon system that are momentary or transient attention has been paid to normal air that cold air, being heavier than warm in nature. It isalso not practical to select flow through the new additions, and air, sinks to the floor. If some method for a furnace with considerably higher allowances made to reduce heat losses removing the colder air is not provided, capacity than the system requires, innew additions.Air conditioning it lies there, and creates the cold feet/ since this approach generally causes a systems are the inverse of heating hot head effect. It is a peculiar observa- system to overshoot thedesired control systems, and their capacities, if central tion, but I have rarely seen cold air re- temperature, will consume more fuel air conditioning is being considered, turn ducts in newer homes. The house I than is actually necessary,and will cost will equal the furnace's capacity under grew up in many years ago in Hamilton considerably more than a furnace with ideal conditions. had a cold air return duct in every down- stairs room, built into the furnace. I re- member them for the sole reason of the number of times my brotherand I had to clean them. That house was a warm house though. In any thermal system there will be a natural flow of heat energy from a warmer surface to a colder one. If the thermal system encloses a volume of space (a house) then this heat flow sets up a mild air flow as well, usually in a vertical direction. This process is called convection, and if taken advantage of can greatly increase the efficiency of the heating system of a home. How many roofs have you looked at in the winter that have snow around the edges, but most of the roof is bare? Have you ever stopped to consider how much lost heat energy that bare roof represents?Ifthat heat had been recirculated back into the house from the attic, can you imagine what savings that would cause to the fuel bill? The real shame of it all is that we pay for that energy, utilize only a small portion of it, and generally let the rest escape out through the roof. THERMOSTAT LOCATION The thermal system in a home is a combination of the heating system, the forced -aircirculationsystem,a convection circulating system, and the Fig. 3. A more thermally efficient air conditioning system would place the cooling coils and temperature sensor and control fan assembly in the attic (1) with the heat exchanger portion on an outside wall. Cooledair system. They form a loop thatis would flow naturally through the cold air ducting (2) with a minimum amount of blower dependent on the inter -relationship of energy, and sink towards the floor. As the air becomes warmer, it wouldrise and be collec- each part. This is why in a properly ted by the warm air return (3) and then to the cooling coils. The heating functions of the furnace are completely independent, and are as in Fig. 1. installed heating system thethermostat

52 ETI CANADA-MARCH 1979 Home Climate Control Principles

is situated in what at first may seem to and cold or hot drafts can be annoying These hints given here arevery basic. be an odd spot. The location of the while trying to enjoy a well prepared But then, the intention of thisarticle isto furnace is usually on the lowest floor, feast. Also, dining and living rooms are get us started on thinking of other ways with the cold air return (if there is one) where most of us do spend our time at ourexistingheatingandcooling being provided from either the area it is home, and it tends to be the area in systems can be made to operate more located in, or from the floor directly which we entertain our guests, so it efficiently.Installationof automatic above it. This is to take advantage of becomes the logical choice for me to thermostats (thatwill decrease the natural convection air flow to aid the select these two areas for temperature controltemperatureatnight), forced air system in distribution of stability. The location of the thermostat additional insulation where required heated air throughout the home. Air withinthisarea has totakeinto (or more insulation if the old insulation conditioning systems should be just consideration the air flow through the has settled, leaving open space), small about the opposite, but you usually see room. Basically, the thermostat should fans to aid airflow throughout the'home air conditioning systems installed as an be located away from the hot and cold (stirring up the room air to get rid of the integral part of the existing heating air inlets to the room, and away from cold feet/hot head effect), covering system so that they can both use the obvious drafts also. The height at which outside windows with semi -reflective same ductingwitha minimum of it is mounted on the wall should take mylar film (reflecting heat back into the renovation and expense. For single into consideration the length of your rooms),locatingthe thermostatin floordwellingsthisapproach is children's arms versus age ratio. If they the most effective spot, and leaving it acceptable,butformultiplefloor are not old enough to understand how set at one temperature, are all things we dwellings the operating efficiency is the system works, keep the control out can do now. reduced considerably, since the forced of reach, or put a locking cover over the air system has to move the cold air thermostat. These covers are readily NON -AIR HEATING against the natural convection flow. available from electrical suppliers, are Most of the above discussion has Also, for optimum efficiency, a cold air transparent, look nice, and install in been slanted towards hot air heating inlet into a room should be near the minutes. It issurprisingwhat a systems. A little thinking will allow ceiling,alongwiththe warmair reduction in fuel consumption occurs transferring these concepts tohot exhaust,taking advantage of when thethermostatisleftat a waterheatingsystems, and convection flow (the cold air inlet and particular temperature. independentelectricalheating the warm air exhaust should also be on systems.In both of these systems, the opposite sides of the room). With HOW TO NOT ADJUST THE moving the hot air from the attic down theheatingandcoolingsystems into the basement will recirculate warm installed and the combinations of both THERMOSTAT air, reducing the heating load required the natural convection air flow and the The primary reason that thermostats of the hot water system or the electrical forcedairflow takeninto are constantly being adjusted is due to heaters. consideration, the ideal location of the someone finding another room either For those of you lucky few who have thermostat starts to become apparent. too hot or too cold. A much more affec- open fire places, several improvements What alsomust be taken into tive way to correct this problem is to have been made that not only make a considerationiswhich roomisof increase or decrease the flow of air to fireplace more luxurious, but a lot more primary importance asfaras the theroominquestion.Thisis efficient as well.. For example, the temperature stability isconcerned. You accomplished by simply going over to "Physicist'sFireplace" holds the can rule out the kitchen immediately, the furnace, locating the ductthat leads burning logs so that they assist in the since the additional heat loads in a to the room in question, and adjusting radiation of heat into the room, while conventional kitchen, (stove, the duct "flapper" until the desired another burning log holder allows airto refrigerator, freezer, toaster and lights) results are achieved. Remember that flow through the support tubes where it will, in the winter provide almost all of when you are doing this, it will take a is heated by the burning wood, and the heat required for that room. In the while for the change to be felt, so be flowsoutintotheroom.Several summer, its another story. That heat patient. fireplace designs circulate room air has to be disposed of, otherwise wife Another simple but very effective around the firebox and back into the cooks before the meal she is preparing. method of improving the efficiency of a room. Ha person were to combine these Bathroomsaremomentaryuse residential heating and cooling system three independent ideas, he would have facilities, so temperature stability is not is to install a fan in the attic. In thewinter an efficient fireplace indeed. If a heat necessary (I agree it is nice, especially this fan should force hot attic air into the exchangerradiatorwere mounted when stepping out of a hot shower into a basement or into the cold air intake of along the inside of the chimney, then an cold bathroom). Since it is preferable to the furnace. This would be recycling air adcitional inexpensive source of hot keep bedrooms slightly cooler (we already heated, so the furnace would water is created also. seem to sleep better in a cool room), we not have to work as hard, and fuel Earlier I briefly mentioned ancient are left with the dining, livingroom, and consumption will be cut considerably. usesofsun,wind,andrainfor recreation room. Since most recreation In the summer this same fan would be environmental control of a domicile. rooms are located in an area adjacent to used to exhaust the hot attic air to the We now have the capability of utilizing the heating system, hot air inlets into outside, keeping the attic cooler, and these effects much more efficiently, the room willbe quite warm, and therefore upstairs rooms too, while also especially when modern materials and considering that this room also tends to reducing the risk of fire in the attic due technology are taken into considera- be irregularly used, the stability of the to the high temperatures created in the tion. Use one way reflective glass to room temperature is not that important. attic from sunshine on the roof. Air allow sunshine to enter a room, and at I personally feel thatthe most important circulation in attics is also important in the same time, reflect the heat back into room to keep at a stable temperature is the prevention of "dry rot"inthe the room (for winter) or reflect heat the dining room, since I enjoy eating, support members of the roof structure. away from a room (in summer). The use

ETI CANADA-MARCH 1979 Do not read page 36. 53 Home Climate Control Principles of plants in a room will help to refresh mentioned ones to be the most referred 1978 (Omega Engineering, Inc) the air, humidify it and actually help to to in my library. If you visit our local Published by Omega Engineering Inc. controlthe temperature somewhat. library you will find books on virtually PO Box 4047, Stamford CT, 06907 Ever noticed how a plant lover's home, every conceivable aspect of TheSolarDecisionBook (R H althoughfilledwithplants, always temperature measurementand control, Montgomery) seems fresh and comfortable? It takes a and through those books you will, like I Publishedby Dow Corning Corp, lot of plants to have a significant effect, have done, open your eyes to what we Midland, Michigan. but they are efficient and inexpensiveto can do now with the materials at hand to ThermoelectricHandbook,Second operate. make our homes more comfortable arid Edition Uses of sun, wind and rainare a lot less expensive to keep them that Published by Cambridge Thermionic detailed in many articles. For reference way. Corporation, 445 Concord Ave., Cam- reading, and scavenging of ideas (after bridge, Mass. 02138. all, a littlehonestplagerism is BIBLIOGRAPHY DecisionMakinginSolarEnergy beneficial), I recommend the following Semiconducting Temperature Sensors System Design publications. andtheir Applications(HerbertB. Published by Design Product News, Published by Instrument Society of Sachse) Nov 1978. America, 1973, Pittsburgh Pa. Published by John Wiley & Sons, Inc. Temperature - It's Measurement and There are many other texts available 1975. Control in Science and Industry, Vol 1 to 4 on thisfield,but I find the above Temperature Measurement Handbook

DEVICE TYPE CHARACTERISTICS APPLICATIONS

SWITCHES Gives a mechanical contact opening or closing Used in low cost thermal protection for ele- Bi-metal switches at a specific temperature, with an inherent ctric motors, transformers, heating elements, Mercury Switch/ Bi-metal coil hysteresis of 10C degrees or more. (for most consumer appliances, refrigerators, automo- combinations. bi-metal switches) The thermal response time tive and Industrial machinery. The combina- Thermal Fuses is quite slow. tion of Mercury switch with bimetal coil finds primary use as a thermostat in home en- vironments. (Covers OC to 200C) SEMI -LINEAR Thick Film Thermistors Generally exhibit a semi -linear impedance Used with support electronics for a variety Thin Film Thermistors change versus temperature plot, (some devices of temperature monitoring and precise temp Thermocouples give a volt/temp characteristic) Devices measurement and control in the industrial Semiconductor Devices generally exhibit very fast thermal response and scientific fields. (Used from -250C to IC Temperature Transducers times, excellent stability, and high reliability. 4500C) TRANSITIONAL Exhibit an abrupt change o f impedance at Primary uses in the thermal protection of Thick Film Pos. Temp. Coef. a specific temp point. Generally have a very semiconductor devices, ICs and in special- Thin Film PTCs fast thermal response time, excellent opera- ized "expanded scale" temperature monitors Thick Film Neg. TCs tional stability, and precise repeatability of and controls. The NTCs are finding increased Thin Film NTCs transition point. useage in the IC fabrication industry as on- board thermal protection. (Presently these devices cover from 10C to 140C)

Table 1. Characteristics of various thermal sensors, and their applications.

ALPHA TUNER. SERVICE The Name of Quality in Tuner Servicing VHF or UHF $13.95 Repairs to all types of tuners Domestic or Import. Colour or Black & White. Varactors $13.95 Tube, Transistor or Varactor. FM Tuners $15.95 UV Combo $21.95 Tuner repairs are our specialty. We use only original or Superior components to Parts and workmanship give top performance and reliability. carryfull12 months warranty. Fast Coast -to -Coast Service. Major parts and shipping charges at cost, ats electronics (dealer net). Bring your tuners to our 3226 6th Street, P.O. Box 172, Montreal centre or forward by mail. Chomedey, Laval, Quebec H7V 3P5 (514) 681-0501 Advertisement

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- 3,9 ZICASti9(j 9 First 0 PLAN TO ATTEND Canada's first CES April 3rd, 4th & 5th, 1979 Tues. & Wed., noon to 9 p.m. Thurs., noon to 6 p.m. CONSTELLATION HOTEL, TORONTO 4 e .b4 The theme of this year's show is "PASSPORT TO PROFITS". Every attendee will receive a CCES passport which makes him or her eligible for a daily draw for free vacation packages for two to such exotic places as Acapulco, the Bahamas, or maybe even Hawaii! Three such prizes will be awarded each day for a total of 9 free Tursda, trips in all. But that's just the 'fun' part of this trade show. You will see every imaginable consumer electronic pro- duct that is available in Canada from automotive hi-fi to CB, microwave ovens, video games, video cassette re- corders, watches, phones, calculators, etc. All items you can sell in your store. So fill out the coupon below today, and we'll see you Friday at the show!

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STATUS TO: Walgram Shows I TEL: 75 The Donway West, Suite 1009 Don Mills, Ontario M3C 2E9 Tel: (416) 444-1188 L Your Zenith Distributor has the parts and accessories you need in oneconvenient place yourZenith One -Stop Shopping Center.

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56 ETI CANADA-MARCH 1979 .qh. ...<5.4.,..96....4. ii,..., _...._ tis FS & Pic. ' 656, co,, wst:;;,:,601-,. /e?_0,. .,:ze,, eo Or e. C.6, 1, 6;)'sj.11610%-,i.k 64Z,'ab eilT

eh, ift.. ote,. 41111P 456, e, . 4r.s. e"e .0 4'1 Jr0,'1?dries News on Zenith, Electrohome, GTE Sylvania and keeping a small business afloat. % 1.66, 6?,

HI! JANUARY 8 and 9 the Zenith Radio Glen Andrews, the national service portables, but looking carefully around

Corporation held the first of their 1979 manager, and he reaffirmed to me that the racks I saw nothing other than shows in Toronto. The event seemed to the System 3 chassis was performing Electrohome products. It may be that be well attended and according to the satisfactorily as expected. No bugs had since it was Friday all finished work was company management it was a very developed and the general public's on delivery. Mr. Hofferdid point outthat successful one. Since I no longer have acceptance of this new chassis was theamount of non-Electrohome to concern myself with possible future extremely gratifying. servicehasnotyetreachedan sales, what to buy, and so on and so Mr. Andrews apologized for the fact appreciable percentageoftheir forth, and seeing no great change in the that the new schedule of cross-country complete work load. receivers on display, I spent most of my seminars had not yet been completed, time in the parts and service sections. but promised to let me havethisas soon SMALL BUSINESS A very effective active flea market was as possible. However since the time run by the service and warehouse now is early January and this will not An old friend of mine who has been a domestic personnel andthereweresome reach the newsstands until March, it electronictechnioanfor extremely good' buys availablefor may be in some instances too late to be many years recently came to see me, and after aperiod of reminiscing !asked those people who arrived on the ofanyreal usetointerested Monday. An old friend of mine (G. & G. technicians. However I would suggest him, as a one man operation, how his own small business was standing up to Electronics) was having a fine time. He that alltechniciansinterestedin is opening a new branch of his very well present day competition. He sounded attending the seminars should off at some length about manufact- establishedservice/sales operation, immediately contact their local Zenith which is going to be a retail partsoutlet. urers' intrusion into the service field representative with a view tofinding out and was not very happy about either George (the boss) informed me that exact times and locations for their area. thoughthenew department was Thanks to Zenith for a fine day. R.C.A. or Electrohome, however he primarily intended for the hobbyist, he finally calmed down and had to admit that in realityhisbusinessstill wouldbe delightedtooffera reasonable discount to all professional ELECTROHOME continued to give him a reasonable servicemen requiring such parts as standard of living. He told me that transistors, triplers, flybacks, rebuilt Reading some previous columns of although he did not consider himself to tuners etc. This operation is not to be mine I came across the November issue be a brilliant technician, he had by hard confused withthe established and was remindedofService work and often extremely long hours, wholesalers, but more in the nature of a Electrohome's expansion into other managedtosurvivewhenother convenience for local technicians who manufacturer's products.I decided to technicians of his acquaintance had need a part in a hurry. To assist in the visit Electrohome's large se -vice centre come and gone. He told me that when stocking of this new enterprise he was on Idema Road to see what, if anything, solid state first began to make its mark was transpiring, and was greeted most purchasing everythinginsight that he was quite concerned about his looked like a good buy. He certainly cordially by Mr. Hoffer and Mr. Bertin, ability to service this new development. took advantage of the old adage, the and we sat down to discuss how things However he assured me that by dint of early bird gets the worm. By the time he were going. It was not surprising to me considerable studying and knowing moved on to the B. & K. exhibition the to find Mr. Hoffer talking about still where to go for advice, and if necessary stockinthe flea market has been further diversification, closed circuit to sub -contract a chassis out, he was considerably reduced. (Any TV being one of their latest additions. abletomaintainhisoperation serviceman seeking some of the older He obviously is very much on the ball in satisfactorily. In passing I would like to Zenithreplacementspeakers, seekingstillfurther electronic say that this man has been in business fly - servicing. With some little reluctance for over 20 years and operates from a backs,etc.,contactG. &G. Electronics.) he let me into the main workshop area, small shop in North Toronto. He did not andI was quite surprised to find no start with a large amount of cap tal, and ZENITH CHASSIS AND evidence at all of other brands awaiting yet by tenacity and perseverance he SEMINARS service. The service reception area was had amassed a not inconsiderable inundated with sets (stereo and TV) and number of extremely staisfied clients. I had a long conversation with Mr. many black and white and colour TV Best of luck, J!

ETI CANADA-MARCH 1979 57 Service News SERVING CANADIANS FOR OVER 25 YEARS ott, ourCoraputev ana SLECTR.01-1. t&, SERVICE a UHF VHF FM VARACTOR TUNERS Great Solid State our Speciality Tead- assurance We service more TV Tuners and the than all other tuner compan- isperformanceback-up: systern maintenanceofproviding ies combined. comp capable good isadequatethan manufacturers, We also service all makes of to any more -system 'The key perforrnance are torsub TV cable convertors. oigood users. techniques, f.lectrohornematntenance, Service party andsystemadvanced you We at third houses using tooffer system engineers pfepared systems cornprehenSive offield are CASTLE staff equipmentminicomputer-bas fullytrained test for pnces. TUNER SERVICE Our sophisticated cornpetinve and maintenanceat ofsupport 24 Cranfield Road, professional penpheTals and theadvantagesElectrohorne East York. Toronto M4B 3H1 Systemof r withService Tel752-7330 1 preventive syste topquality cost, Low flexibility Electrohorne - of programmesservice fAectrohorneis acliviion aseventy 50 Projects Using Relays Service with over and Individualizedcoverage resourc Electrohorne - Company products Nationwideengineering Service Canadian quality - statistic limited, a of providing ProtessionalrePorting, ser SCRs Cl Triacs oftwenty-two - emergency yearhistory made up Maintenance is comprehensive - on By F.G. Rayer service. industry 24 -hour network the most - 102 pages. Ourservice Canada, electronicsprepared acToss in the team branches anyone with a Published March 1977 ht add,of statted and we is tully instructions Relays, silicon controlled rec- branch to your Each you, tifiers(SCRs) and bidirect- towork for ional triodes(TR IACs) have a guidelines. wide range of applications in Look what Electrohome is now into! A recent ad. electronics today. These may extend over the whole field Before closingI would like to point control digital tuner.

4 out to our readers that I unfortunately A buffet or Smorgasbord lunch will be of motor control; dimming know very little about service problems andheatcontrol;delayed, provided. 4 outside Metropolitan Toronto. I would Meetings will start at 9:30 a.m. at: and sensitive timing light very much like to hear from service Barrie: Wed Feb 14, Continental Inn circuits and include warning persons across Canada on any matters, 395 Dunlop St., W. devices, various novelties,li- largeorsmall,pertainingtoour Toronto: Tues & Wed Feb 20, 21 ght modulators, priorityin- industry.Pleasewrite me careof Holiday Inn at Warden and 401 dicators, excess voltage brea- Electronics Today. Kingston: Tues Feb 27 Holiday Inn kers etc. Belatedly, my I wish you all a Happy 1 Princess St. Inthisbook,the author, and Prosperous New Year. Chatham: Tues Mar 6 Holiday Inn Best of luck, Richard Cartwright. Mr.F.G.Rayer has given 25 Keil Dr. tried and practical working London: Thurs Mar 8 Lamplighter circuits which should present LATE NEWS ...GTE SYLVANIA TO Inn 591 Wellington HOLD SEMINARS. Here's what you'll Jordan: Wed Mar 14 Beacon Motor the minimum of difficulty. learn about, when and where. Hotel, Q. E. W. & Jordan Rd. $2.75 plus 34 postage. E48 and E49 feature a VIR module that Belleville: Wed Mar 21, Four Seasons provides automatic tint and colour Hotel, 11 Baybridge Rd. order. Pleaseusethe cardto control cicuitry. Cambridge: Wed Mar 28 Holiday Inn IMF 11, IF AEI, E49 is now available with a remote 401 and 24 N.

58 How about a subscription? See the card facing page 3. ETI CANADA-MARCH 1979 D\1K Q

% 4/24, ss°"s,zy 6°0'4 57-7 °%tj, e' /4VI, # .904, *1141*

Bill Johnson, VE3APZ, figures cleanliness is next to keeping Canada's repeaters repeating. He also draws some fire from the RSO.

WE'RE VERY LUCKY here in Canada. a prettylonely and boring job, yet be a very good idea, and many said so. Our southern neighbours have reams there are plenty of people willing to There were a few individuals, however, andreamsofregulationspertaining do it - just goes to show how dedicated who complained bitterly at having to toamateuroperation. Justabout some amateurs are. sign, saying we were taking away their everyconditionyoucouldpossibly rights and freedoms etc etc., but they think of has been - and thereisa IN CANADA signed, because they wanted the codes, regulation to cover it.The most pro- What's this got to do with us safely and they didn't want to be labelled as lific regulations are those covering VHF above the border you say? Plenty. dissenters.

and repeater operations.The way in Since America is ten times the size of As I said before, we are very lucky which a repeater station can be operated Canada, thenit follows that they will in Canada.For example, there are no and must be maintained is spelled out have tentimes theproblems,right? specific regulations on how a repeater explicitly.One would think from the The problem (let'stakeautopatch is to be run. There are some 'guidelines' degree of complexity of the regulations abuse,for example) thatis not big however, which basically state a repeat- that safety of life at sea, for example, enough yet to raise an eyebrow at the er should have an identifier, a timer, was totally dependent on the proper D.O.C.hasprobablyalready caused and thelicenseesshouldbe able to operationof an amateurrepeater theregulation - writersin America control it by physical or remote means station.Itis not my purpose to eluci- to sharpen their pens. So when we see possibly assisted by two or three people datetheentireregulations inthis regulationsbeingputintoeffectin whom he may designateinwriting column, but a few points may serve America then we should start taking to the department.This is the way it as words to the wise in Canada. One of a good hard look at the way we are is, and THIS IS THE WAY IT WILL the most recent effects of the tight doing things here, and possibly mend STAY, as long as the people that make regulations down south has been the our ways beforeitis too late. Ina therulesseethat we canregulate shutting down ofallfully -automatic way, you could say we almost have a ourselves and behave ina mature and phone patches (autopatches) unless a crystal ball. sober way with a minimum of super- central operator is on duty. vision.Two metre FM is a very good A central operator is a duly licensed TFM CASE example of this, and one to which most amateur designated by the licensee of a Last year, at a directors meeting of amateurs can relate, but is spreads into repeater to have control over the repeat- the Toronto FM Communications Soc- every facet, every subdivision of our er by using touchtone, usually on secret ietyInc., we decided that we should hobby.As long as we obey the rules 450 MHz inputs. The central operator's takeallthe operating cautions, notes we have, and don't try to stretch them job is to monitor therepeater and and hints that we have publishedin tosuiteourselfishwants then we shutitdownifany technicalmal- our bulletin over the ten year life of won't have to worry about having our functionor operator's abuse (usually the Society and formulate them into privileges taken away - 'the squeaky the latter) occurs.He has to sit there a set of rules for the use of our four wheel gets the oil'. 73 till next month hour after hour listening to the absolute repeaters. We went through several QRM LETTERS drivel that sometimes goes on on two directors' ideas of drafts, weeded out The January QRM column contained metres and is personallyresponsible the bad ones, amplified, re -wrote and comment on the RSO's proposed for any breach of the regulations that explained,andendedup withtwo repeater. Following its publication, I goes unnoticed and is allowed to con- pages of strict 'guidelines', to be follow- tinue. The number of central operators received a phone call from one of the ed by everybody using our repeaters. Vice Presidents of RSO Repeater Inc., is usually limited to two or three, and We changedallourrepeateraccess who says I only gave half the story. the job is further made difficult by the codes because they had been broken He has since written to me and his letter factthatyou cannotperformthis andpassed aroundovertheyears, functionfrom yourcardue toan and only gave them out to fully paid appears on the following page. Others on the RSO executive have also written, interpretationof a regulation which up members who had read the rules their views will be aired in future issues. says users of remote base stations have and signed a form to say they had read to be fixed stations themselves. them and would follow them.To the Several people have written in asking This makes being a central operator majorityof people, this appeared to how they may become an amateur. ETI CANADA-MARCH 1979 59 QRM

For Mr. Saik Teewatctah of tent 13, VE3KSR which was, as far as we are selfsacrificialassistance to othersin CheegaboogooReservation,Southern aware the first repeater in Canada to be pioneering a system to transmit code Northwest Territories,I can only advise licenced to a club and the first to use practice high in quality, reliable, inex- a good book and lots of self -study. touch tone for contol. pensive to use, and never before avail- (Not the kind Gurus peddle). Those In1969, a group of us who were able to would-be amateurs. who live in the larger population centres involved with repeaters formed what is Lloyd and I discussed the idea of will usually (almost always) find a radio now the Western New York and South- establishing a repeater at his house so club within driving or bussing distance ern Ontario Repeater Council. In 1970, others could originate code practice and of their home.There are several ways I was involved with the development feed it out on the network. Should we of contacting these clubs:- and testing on the Multi -Channel boards once againscroungeandbuildto 1.Beg, borrow, steal,or,as alast for VHF FM which was published in the produce a repeater for this project, or resort, buy a copy of the 'Radio Am- VHF Repeater Manual by AR R L.In should we solicit donations and pur- ateur'sLicensing Handbook' by Jim 1976, wehelpeddevelopthe now chase the best, most reliable repeater Kitchin VE7KN, publishedanddis- famous KSR power supplies for amat available? The answer to that question tributed by ALH distributors, P.O. Box eurs to use with their surplus mobile for me was clear after having built two 27, Vancouver, B.C.As well as being equipment released from a communica- repeatersandspendinghundredsof a valuable text for study, it also lists tions company which our club distribu- hours in the procbss: let's for once put Canadian Amateurs, province by pro- ted to amateurs all over Ontario. Thai on a super reliable commercial quality vince.Look through the list and find same year, VE3WFM repeater went on repeater for this demanding job of code one closetoyou. Get his number the air in Waterloo which was built and practice. from the phone book and give him a owned bymyself.The Kitchener I presented the idea to the Kitchener call. Tell him you want to learn how Waterloo Amateur Radio Club honour- Stratford FM Association Inc.in May to be a ham and don't know where ed me with the "Amateur of the Year" 1979. They agreedthat we should ,tostart. He'llprobablyinvite you award in 1977. proceed with the project and since a over to his shack to see what it'sall As youcan see from the above group in Londonhadobtained a about. He'llatleast be able to tell paragraphs,I too have been "intimately Wintario Grant to establish a repeater, you where thenearestclubmeets, involved in 2m FM for ten years." I'm we agreed to apply for a grant as well. and probably be able to put you in thereforeveryconcernedwiththe The next question to consider was touch with the person whoruns it. negative connotations which I feel you whether this project for ALL 2. Canada has two national organiza- would leave with readers of your article. AMATEURS ofOntarioshould be tions for amateur radio. Let me back -track just a little. After sponsored by alocalKitchener area a) The American Radio Relay League listeningto several busyrepeaters, group, or whether a large organization Canadian Division, P.O. Box 418, including VE3KSR, it occured tome such as RSO should become involved. SACKV I LLE,N.B.,EOA 3C0 (506) that much of the time that the repeaters Harold Braun and I presented the idea 536-1208. were on the air, they were being used in to the RSO executive and they thought b) CanadianAmateurRadioFed- a frivolous manner. A NEW CONSTR- it was a fine project, and agreed to help erationInc., P.O. Box 356, Kingston, UCTIVE use that they could be put to us getitgoing. A new incorporated Ontario, K7L 4W2. would be for CODE PRACTICE. This company, the VE3RSO Repeater Assn. Both of these organizations have lists code practice on a DAILY BASIS would Inc. was formed with Harold Braun as of clubs to whom they can refer you. assist new people to get into amateur President, and George Davis and myself Mostclubs have veryinexpensive radio. They would simply tune into the as Vice Presidents. training classes weekly starting in the LOCAL REPEATER on a readily This repeater will be on the air in the fall and going until spring. available public service band receiver. spring of 1979 and will have battery 3. You can get a book called 'From Thus, they would not have to invest ina backup supply designed to run for 3 five Watts To A Thousand' at your communicationsreceiverto pick up days in the case of a major disaster. It local Radio Shack store. W1AW. I proposedthisidea to the will have a micro -processor for the code The standard study guide for be- VE3KSR group, and they approved the generation, storage, and other "tricks" gining amateurs is 'Ham Handbook for system. forMorse code only.KeithBently, Beginners'byGlen Emo, VE3EME, Lloyd Ferns, VE3BZF,of the VE3DHL, is the engineer in charge of published by Arta Publishing, Box 571 Orangeville area, started to workon a thisarea of the project. While morse Don Mills, Ontario M3C 2T6.Don't teletype system of generating Morse. On codeisthe primary function of this buy thisif you plan to joina club December 9, 1975, he went on repeater and itis the largest and most course - they quite often buy them VE3KSR with about 150 sessions of costly repeater ever planned in this area, all together and get a discount. codepracticeat15,10,71/2, and 5 itwill be areal asset to the amateur words per minute. The followingyear, fraternity. We are awaiting approval RSO REPEATER COMMENTS he conducted 187 nightly sessionson from Wintario and as you are probably I would like to express my profound VE3TTY and VE3KSR. In1977, he not aware, the total budget represents disappointmentwith thetoneand went on the air with a 200 foot tower onethirdcashonhand onethird context of your article on the RSO and 6dB antenna to feed code practice Wintario grant, and one third donated Repeater Project in the January issue. to 6 repeaters simultaneously on labour. My involvement with VHF FM began 147.990. The full story of his efforts Recently I have been appointed to in 1963 when I worked on mobile radio appeared in the April 1978 issue of the head the VHF -UHF Advisory Commit- equipment and repeater stations eight Ontario Amateur. This year, Lloydwas teeofthe RSO and the Frequency years commercially. In 1969, with some awarded the Clifford Marsh Memorial Study Committee of the Western New assistance from other amateurs, I built Trophy, "Amateur of the Year" for his Continued on page 66. 60 ETI CANADA-MARCH 1979 Shortwave World SWLs and QSLs SWLs and QSLs

John Garner describes the fascinating hobby of collecting QSLs and tells how to go about getting them.

SINCE THE VERY early days of radio broadcasting,listenershavebeen sending reception reports to far away radio stations which they have heard. Perhaps the first request for reports from a station occured on Christmas Eve, 1906 when the first radio voice transmission went out to ships owned by the United Fruit Company from the Company's office in Brant Rock, near Boston, Mass. The host of that program which included Christmas greetings and music fortheoccasion, was Reginald Fessenden, the Canadian who invented radio as we know it to- day. That particular program was the first time radio was used to carry the human voice and also the first time music went out over the airwaves. A good reception report contains the following: Technical details which will enable the station's engineering department to evaluate the quality of the signal being sent out to a particular area of the world; Personal comments which help the producers to improve the contents of their programs to suit Thank you for your report on the reception the needs and wishes of their listening of our transmission from the audience; Details from programs heard in order to make verification possible. H. F. Verwoerd Shortwave Station WHAT TO SAY

Stationsreceive many reception 1j,'-11-761-IME reports every day so it is very important DATE: (GMT)22;0 to make your report easy to read and 95P5 understand. Many clubs issue printed FREQUENCY: kHz forms for this purpose. If possible your reportshould betypewritten - Mr. J.J. Garner, otherwiseprintedorwrittenvery RADIO RSA clearly. The Voice of South Africa 980 Georgina Bay, The language you use to write your Box 4559, 2000 Johannesburg, South Africa report should be in the same language Thunder Bay, as the program heard orthe language of the country broadcasting the program Ontario heard. English may be used for your DRAKENSBERG South Africa Tugela falls and the super/view from atop -The Amphitheatre" CAI,,ADA P7$ 3H7 report if it is going to one of the major Illth Royal Natal National Park. DRAKENSBERG Suld-Afriaa international broadcasters but in most Tugela-waterval an dl. pragtiga ultsig van -01 Arnfiteatar" cases will be of little use when writing to al in di Royal NatINasionala Park. most of the smaller domestic stations

ETI CANADA-MARCH 1979 61 Shortwave World where English may not be understood. interfered with, especially when they Personal comments should be on an start transmitting on a new frequency. If enclosedletterseparate fromthe you can identify an interfering station technical portion of the report. In this thestationisappreciativeofthis way the technical section of your report information. Also it is important to let can be passed on to the engineering them know if the interference is on the department while your comments will same frequency or on a higher or lower be directed to the program producer. frequency. If a station is being jammed, When writing a reception report to a this information should also be noted station, probably the first thing that you along with the type of jamming as well should do would be to clearly print your as you can determine it. name and address at the top of the page Noise Atmospheric noise from (as well as at the top of each additional electrical storms and polar lightis page). Many SWLs have criticised included here. The source of the noise stations for not OSLi ng when in fact the may be thousands of kilometres away station's staff were unable to read the and may just show up as a high noise name and address or it was completely levelinyour receiver. Man made missing from the report. electrical interference, such as vacuum While listening to a program on the cleaners,hairdryers,etc,are short wave bands it is always a good not included in the code. idea to jot down a few notes to enable Propagation Thiscouldbetterbe you to prepare your report later on. A described for most as fadi ng. A 5 for this tape recorder is also very useful in this portionof the SINPO code would respect to help you later on with indicate a stable volu me throug hout the program details. recorded logging period, while a 1 Mention the name of the station would indicate that the program was heard at the beginning of your report. fading completely away at times. State the frequency in kilohertz as Overall Merit This is a measurement of exactly as you can. The date and time of the readability of the station's signal. reception (in GMT) should be given Thestationwouldappreciate a next. Your local time is of no use to a comparison of their reception with station on the other side of the world so other stations on the same continent GMT (or Coordinated Universal Time, and broadcasting in the same bands. which isreally the same as GMT) Your local weather conditions are of should always be used for international no use to the station since radio broadcasting stations. propagation is mainly influenced by ionospheric conditions and not by If you live in a small community, weather in the lower atmosphere. explain the location of your town by Tell the station what type of receiver telling the station the distance and and antenna you are using. You might direction from a large, well-known city. mention the number of transistors Five or six details about the program and/or tubes in your receiver and the heard over a period of at least fifteen year in which it was manufactured. The minutes (preferably longer) should be antennalength andheight above sufficient to prove that you did indeed ground should be stated in metressince heartheprogramthatyouare the metric system is in use in almost all reporting. Some typical details might parts of the world. Be sure to indicate include the name of the program, the whether you use an indoor or outdoor name of the host or announcer, the antenna. name and/or composer of a piece of Iwill continue this discussion about music, the names of any products being Signal Strength If your receiver has a reception reporting and the resulting advertised,thesubjectof a built-in S -meter you can useitto OSL cards that you may expect in commentary or discussion. It is also a determine signal strength.If the S - return for your reports, in next month's good idea to list the time (in GMT) of meter shows between 1 and 3. the S (for column. each item you report. signal strength) willlie listed as 1; between 4 and 7, S = 2; between 8 and 9, SHORTWAVE WORLD MAILBAG RECEPTION QUALITY S = 3; between 9 and 9 plus 20 dbiS= 4; Andre Renes writes to say that he is and over 9 plus 20 db, S = 5. interested in converting a TV tuner for This is, of course the main purpose of If you do not have an S -meter on your VHF reception.Ifanyone has any the report - to let the station's staff receiver then you can judge the signal information on such conversions drop know how well their efforts are getting strength from the amount the volume us a line and we will pass it on to other out to their target areas as well as control has to be turned up from zero. A interested hobbyists. elsewhere in the world. signal strength of 5 would only be used Andrecontinues"Ihavealso For the major international for stations that are coming in as strong experimented with adding a variable broadcastersthe SINPO codeof as a local station on your medium wave condenser to the existing one in my reporting is preferred. This code is radio. Heathkit RX1 receiver. This allows me explained in Chart 1 and the following InterferenceAllstationsarevery now to tune in not only to the amateur paragraphs. interested in knowing if they are being bands but also to regular shortwave

62 ETI CANADA-MARCH 1979 SWLs and QSLs

broadcasts in the 16 -49 metre bands. I and fine-tuning bandspread are portable has the AM, FM, LW, PSB, and have already listened to some very included for shortwave. Also featured aviation bands as well as five short wave interestingbroadcasts fromEgypt, are an automatic AC/Battery switching bands covering the frequencies Australia,India,Israel,Netherlands circuit and a convenient battery check between 1.6 and 26 MHz. There is and many more... I am also interested button. The TFM-8000W measures 210 precise tuning on all 10 bands with LED in what is necessary to receive Amateur mm high, 290 mm wide and 105 mm tuning indicator, tuning meter and fine TV (Slow scan) - Isuppose a TV deep and weighs 3.2 Kg with batteries. tuning bandspread for SW. The BFO receiver could be rewiredfor this The list price in Canada is $199.95. signal generator allows reception of purpose." ICF-5900W - This set has the AM and SSB and CW signals and the PSB and Sincethis columnismeant for FM bands as well as three short wave aviation bands have a squelch control. shortwave listening, it is very nice to bands which cover the frequencies The CRF-5100 has a built-in AC power know you are enjoying broadcastsfrom from 1.6 to 30 MHz. The precision core but may also be operated or 8 'D' someofthe major shortwave tuning along with a built-in crystal cells. A World Time Zone reference broadcasters. In regardtoyour marker provides accuracy to within 5 chart is built into the case to allow the question about amateur TV reception, kHz on the shortwave bands. SSB and usertodeterminethebest SW perhaps this should be directed to the CW reception are also possible with this reception times of countries and cities Ham column in ETI. One manufacturer receiver's BFO switched on. The ICF- throughout the world. Measurements of Amateur slow scan TV equipment is of the CRF-5100 are 230 mm high, 340 Robot Research Inc., 7591 Convoy 5900W also has a battery check and tuning meter. Operation is by three 'D' mm wide and 160 mm deep and it Court, San Diego, CA 92111, USA. cells or on AC with the AC adapter weighs 6.4 Kg. The list price in Canada Good luck, Andre, in your conversions. suppliedwiththeset.Thisradio is $499.95. I'dlike to take this opportunity to measures 235 mm high, 222 mm wide Next month's equipment review will thank those who have enjoyed this and 102 mm deep and weighs 2 Kg. The feature the other three Sony shortwave column and taken the time out to write Canadian list price is $239.95. receivers - theICF-6700W,ICF- and let me know.If you have any 6800W and the CRF-320. So until then questions about short wave radio write CRF-5100 - "Earth Orbiter" - This 73 and good listening. to Shortwave World, P.O. Box 142, Thunder Bay, Ontario, P7C 4V5.

EQUIPMENT REVIEW 0, 0 A name well-known in the home entertainment field in Canada is the Number Signal Interference Noise Propogation Overall Sony Corporation. Sony introduced Strength Merit the world's first pocket sized transistor 5 Excellent Nil Nil Nil Excellent radio. They also produced the world's 4 Good Slight Slight Slight Good first AM/FM transistor radio, the world's 3 Fair Moderate Moderate Moderate Fair firstmedium wave/short wave 2 Poor Severe Severe Severe Poor transistor radio and the world's first 1 Barely AudibleExtreme Extreme Extreme Unusable radio using integrated circuits (ICs). With a record like this in the radio field Chart 1. The SINPO code. you can be assured of sound quality from Sony. Sony manufactures seven portable receivers that include the short wave bands. These range in price from $150 to $2150. ICF-5800L - This is a compact five band portable which features AM, FM, and LW (longwave) as well as two short wave bands covering the frequencies between 1.6 and 12 MHz. It has a large dynamic speaker, separate bass and treblecontrolsand a telescopic antenna. A built-in timer turns the radio on or off automatically. It is supplied with an earphone and carrying strap and operates off 4'C' size batteriesoron house current with the optional AC adapter. The ICF-5800L measures 208 mm wide, 228 mm high and 84 mm deep and weighs 2 Kg with batteries. The Canadian list price is $149.95. TFM-8000W - This receiver features AM, FM, PSB (Public Service band) and three shortwave bands covering the frequencies from 1.6 to 26 MHz. It has a built-in AC power cord or it can be operated on 4 'D' cells. A tuning meter

ETI CANADA-MARCH 1979 Please mention Electronics Today when responding to advertisements. 63 ETI Softspot

Calculator Hangman

Use your calculator for word games. By Rick Campbell of London Ontario.

THIS PROGRAM is a calculator version ENTER: ENTER GUESS DISPLAY LETTERS WORD USED 4 of the popular game "Hangman". The 00 R/S A 0 A ..** object of the game is to guess a hidden R/S 04 R/S E 3 AE *E** word which has been entered by yourStep 3. The player enters a guess. 08 R/S I 0 AEI *E** 41 AEIT opponent. Guesses are made by entering a The resulting game is shown inFig.1. 19 R/S T TE*T 18 R/S S 2 AEITS letter from the alphabet which the player TEST believes is contained in the hidden word. Fig.1. Sample game. Because calculators only accept numerical data the letters are represented by num- my.zo.::kw:::::::::z;:ms,kks.:mx,mm.*:...w:;szita:mm:ozwc:::**:::.,2m.s.sww..w..94km:x*.m...... wmcz&v.a: ber combinations, with 00 being "A", up Progarn for TI SR 56 to 25 being "Z". LOC CODE KEY After a guess has been made a response 00 38 CMS 01 1 04 4 will appear on the display.If the letter 33 STO 35 SUM 64 x guessed is not contained in the word, the 01 1 30 04 4 34 RCL display will indicate a zero.If the letter 33 STO 34 RCL 05 5 guessed is contained in the word the calc- 02 2 01 1 60 94

ulator display will show the position of 01 1 54 ± 35 SUM the letter in the word. 33 STO 01 1 06 6 Example: The hidden word is "LOUD" 05 5 00 0 27 dsz Theplayer'sguess is "0" (14). The 41 R/S 00 0 02 2 display indicates a 3, the third position 33 STO 94 08 8 from the right. 10 00 0 33 STO 34 RCL If the word contains more than one of 33 STO 07 7 02 2 the letters guessed, the display will indi- 03 3 40 29 INT 33 STO cate the position of all the correct letters. 41 R/S 33 STO 01 1 Example: The hidden word is "STRUT". 54 01 1 70 34 RCL

The guess is "T". The display will indi- 01 1 34 RCL 03 3 cate a 41, fourth and first positions. 00 0 07 7 33 STO SAMPLE GAME 00 0 12 INV 00 0 For TI SR 56. 94 29 I NT 34 RCL Step 1. The word is selected and entered 32 x y 12 INV 06 6

by the opponent. In this case we will use 20 01 1 37 x = y 54

"TEST". 33 STO 06 6 01 1 ENTER: 05 5 50 03 3 00 0 RST 00 5 01 1 94 19041819 33 STO 00 0 80 41 R/S R /S 04 4 30 Prod 22 GTO

Step 2. The word length is entered by the 33 STO 05 5 01 1 opponent. .!; 06 6 34 RCL 04 4 64 ETI CANADA-MARCH 1979 Calculator Hangman

START FLOW CHART SYMBOLS

riInformation Output

Data to be Input

/ENTER WORD LENGTH LOOP Branch COUNTER O

Operations

POSITION CTR = 0 OUTPUT CTR = 1 DISPLAY CTR = 0 V Program Entry Point

ENTER GUESS End

INCREMENT POSITION CTR, MULTIPLY DECREMENT POSITION CTR BY LOOP CTR OUTPUT CTR

SOIFTSPOT isETI's programmable calculator software department. We ADD RESULT TO know there are many of you who have IS GUESS YES DISPLAY CTR EQUAL TO NEXT gone to a lot of effort to write routines LETTER? foryour machines - how about sharing the fun. Send us a copy of your petprogram,preferably withflow chart. To make things interesting we NO MULTIPLY OUTPUT CTR BY 10 will restrict our choices to only those programs making use of loops or conditionals. All programs we publish will be paid for.

Mad to: ETI Softspot Unit 6, 25 Overlea Blvd., IS LOOP YES DISPLAY TORONTO, Ontario COUNTER EQUAL "DISPLAY" TO 0? M4H 1B1 COUNTER Don't forget to mention what kind of calculator you use - and we'd also be interested to know where you bought it.

ET! CANADA-MARCH 1979 65 JanaS. PLe."931 SEAT4rN 4. A 1 rc rEs ot ELECTRONICS LTD. You, ApVcA77.5C4454/7" 01E31461 7tyls .-0e'77. use ...NIUE. CT: ANenlOry 3c -N44-0 1./Nil 0,15 wt.., Pk., 004', Fetii-T ieug OULC4,,Es,uirrw You.. Totemic, MA/we e AvOthrs.5 ETI irf3S46C mu -roe Arfu r1.1 -H 1B1 ^lae ,,,,e,Z Distributors stocking Jana Projects:

A-1 Electronics ISLINGTON. ONTARIO Arkon Electronics MARKET PLACE TORONTO. ONTARIO Atwater Electronics MISSISSAUGA. ONTARIO ****FREE ADVERTISING**** Brant Electronic Supply BRANTFORD ONTARIO

Carsall Industries SAULT STE MARIE. ONTARIO OLD TUBES FOR SALE: 024A-42-80-89Y- FOR SALE: SENCORE ANALOG FET GD6-1642.EICO 625 TUBE TESTER. Robert J Buckland Co EICO 232 VTVM. A. BOISVERT, 4830 MULTIMETER MODEL FE 149 PUSH- LONDON. ONTARIO BUTTON RANGE/FUNCTION SELEC- DES PERVENCHES, ORSAINVILLE, QU- TION. EBEC 7, QUE. G1G 1R7. LINE OPERATED FOR BENCH Dominion Radio Ltd USE. CALIBRATED AND WITH MANUAL TORONTO. ONTARIO $30.00. B. WINTER, 6528 BUTLER ST., VANCOUVER, V5S 3K9 (604) 435-6215. General Electronics Co CLEARING OUT ELECTRONIC SHOP. WILLOWDALE. ONTARIO SEND ME YOUR NAME AND ADDRESS- FOR FREE LIST. FRANCIS LECLERC, WANTED: HEATHKIT HW-101 H.F. TR- Gladstone Electronics C.P. 1554, GASPE, QUE. POC 1RO. ANSCEIVER IN GOOD CONDITION. TORONTO. ONTARIO ALSO INTERESTED IN ACCESSORIES. Heath Company IF REPLYING, STATE PHONE NO. BERNIE MAC INTYRE, MARSHFIELD, MISSISSAUGA, ONTARIO FOR SALE! COSMAC ELF. ALL PARTS P.E.I. CIA 7J7, 902-892-3236. NECESSARY FOR BASICELF. NOT Jerry's T V ASSEMBLED. INCLUDES 14"x 8"x 4" SARNIA. ONTARIO CABINET WITH ASSEMBLED FRONT FOR SALE: SENCORE CB ANALYZER Kesco Electric Supply Ltd PANEL, TOGGLE SW. ADDRESS, DATA CB42 CB PERFORMANCE TESTER CB41. PETERBOROUGH. ONTARIO AND STATUS LEDS, SPRING -LOADED PRICE: $1,290.00 WITH ALL ACCESSOR- TOGGLE SW. ARE USED FOR INPUT, IES, LIKE NEW. ANDY CHAN (465-2889) Kingston Electronic Supply Ltd SINGLE-STEP AND ADDRESS LOAD. 330 DIXON, APT. 704, WESTON ONT., KINGSTON. ONTARIO ALSO INCLUDED IS8 VOLT 7 AMP M9R 159. POWER SUPPLY, ASKING $100. HENRY NING, 21 LAURIER CRES. KAPUSKA- Lighthouse Electronics 5ING,ONT P5N 2P7. (705) 335-5097. WINDSOR. ONTARIO FOR SALE: BINATONE MICRO -CASS- Lamp Land Ltd ETTE RECORDER WITH VINYL CARRY PETERBOROUGH, ONTARIO CASE. $30.00. :MULTI -SOUND EFFECTS FOR SALE: PCB MANUFACTURING GENERATOR- USES EQUIPMENT, . SPRAY ETCHER, SPRAY SN76477 CHIP - M ISupply Co Ltd LIMITLESS POSSIBILITIES- W/SPKR. BELLEVILLE, ONTARIO DEVELOPER, DIP COATER, VACUUM AND INSTRUCTIONS- $25.00 ASSEM- OPERATED LIGHT FRAME. BENCH TOP BLED. :T120 SWITCH KEYBOARD - Neutron Electronics Ltd TYPE, CAPACITY 12x12 INCH DOUBLE 1 -9,0,00,+, -,%,ETC. $5.00. :ASSORTED GUELPH. ONTARIO SIDED. SUITABLE FOR LIMITED RUN IC'S, AND SUPPORT COMPONENTS- PRODUCTION. ALL REBUILT LIKE NEW NEW AND USED- ASK FOR IT! PLEASE Niagara T V BARGAIN PRICED, OR TRADE FOR WRITE AHEAD BEFORE ORDERING! NIAGARA FALLS. ONTARIO SMALL METAL LATHE. MR. DAVID, B.J. PALMER,1303 -96THAVE.S.W. 484 MURRAY ST., PETERBOROUGH, CALGARY, ALTA., T2V-0Y2- (403) Northwestern Electronics Supply ONT. (705) 748-6769. 252-3031. OWEN SOUND. ONTARIO

Provincial Electronics Distributors LONDON. ONTARIO

Radio Trades Supply Ltd TORONTO. ONTARIO

Sonic Northern Continued from page 60. SUDBURY. ONTARIO

Teltronics Ltd York and Southern Ontario Repeater January1979 wouldhelp themto SCARBOROUGH. ONTARIO Council. In your article, you stated that become interested in Amateur Radio?? "Provincial D R Walling Co Ltd Organizationswere not We inthe RSO areinterestedin LINDSAY. ONTARIO interestedinit." I presume you are doing the best job for the Amateurs of excluding RSO since Waterloo Electronic Supply I remember many Ontario and we would greatlyappre- WATERLOO. ONTARIO fine articles in the Ontario Amateur by ciate your support in ETI. Wouldyou Jim Western Radio Supply Co McCullough, VE3CSO, who is consider doing an article onour code HAMILTON. ONTARIO indeed an expert in VHF FM. practice schemeina future issue? I Billinyour Westown Electronics article,youmissed would be pleased to assist. TORONTO. ONTARIO entirely the reason for our newrepeater Newcomers to our hobby will then and proceed to condemn RSO. ETI find out some helpful ways to learn Canada magazineis very likely to be Morse Code which of course isa pri- If you cannot find Jana picked by agreat many people who mary requirement. Projects in your area, would beinterestedin becoming an contact Doug Mann, amateur. Do you think your article of 73, J. Riddell, VE3AMZ. Jana Electronics Limited, P.O. Box 489, Winnipeg, 66 Manitoba R3C 2B3. Clever, easy -to -make, inexpensive jana kits Produces more random numbers than Las Vegas!

True randomness is hard to achieve in any kind of mathematics. But Jana Dice Game can keep the numbers more unpredictable and 'honest' than old-fashioned real dice, once they are even slightly worn. Friends who are unfamiliar with the powers of electronics will be most impressed with your Jana Dice Game's never - failing ability to reproduce faithfully the patterns of dice. The easy -to - follow Jana plans show you how to program your Dice Game so that the Jana kits for many useful and entertaining 15. O -20V Power Supply dots light up invariably in true dice purposes. 16. Single Channel Color Organ 1. Automatic Headlight configurations. Reminder 17. Electronic Siren Like most Jana kits (see list), Dice 2. Battery Operated 18. Slimmer Strobe Ught Game comes complete with detailed Fluorescent Ught 19. Tone Generator 3. Bug Shoo 20.5 Transistor 1 Watt plans, all parts except battery, and 4.Code Oscillator Amplifier the container converts to case. If you 5. Crystal Radio 21. Tube Continuity Checker 7. Curiosity Box II 22. Xenon Strobe enjoy putting electronics together, 8. Daily Lighter 23. LJ 12016A Color Organ here is your chance to harness 9. Decision Maker 24. Loudmouth Siren mathematics and make something 10. Fish Caller 25. Roulette Wheel 11. Hi Power 12V DC Flasher 26. Electronic Sheet Game new and different of every dice - 12. Photo Electric Night Light 27. Electronic Dice 13. 6V Power Supply 28. Super Roulette throwing game from Monopoly to 29. FM Mini Broadcaster Craps. 14. 9V Power Supply

Jana Electronic Projects are available through Cam Gard Supply For institutional inquiry contact: and other distributors across Canada (partial list on facing page). Mr. D. Mann Jana Electronics Limited

111111111111111111M11111111111HIBUOUNI CAM GAR© SUPPLYLTD

sommossommummommoussinsusses 0000000000 esomesso 00000 soon Vancouver Kamloops Calgary Edmonton Red Deer Regina ELECTRONICS LTD. Saskatoon Winnipeg Halifax Fredericton Moncton P.O. BOX 489, WINNIPEG, MANITOBA R3C 2J3 ETI Data Sheet CMOS 555!

One of the few exciting updates for the 555,a CMOS version from Intersil.

The 7555is inmost casesadirect frequency modulationintheastable frequency, are essentially independent replacement for the 555 timer. Because mode or even inhibition of oscillation, of the supply voltage. the 7555 does not produce large crow- depending on the applied voltage. In the The frequency of oscillation is given by: bar currents in the output driver, itis monostable mode, delay times can be 1 f = 1.46 not necessary to decouple the supply changed by varying the applied voltage t=(RA + RB)C lines with a large capacitor close to the to the CONTROL VOLTAGE pin. device. Secondly the controlvoltage decoupling capacitors are not necessary. RESET Thus for many applications two capacit- The RESET terminal is designed to have ors can be saved by using the 7555. essentially the same trip voltage as the The output driverisa CMOS inverter standard bipolar 555/6, i.e. 0.6 to 0.7OUTPUT capable of driving two TTL loads. volts.Itpresentsan extremely high -- input impedance. The mode of MONOSTABLE OPERATION operation of the RESET functionis, I OPTIONAL I CAPACITOR Initially the external capacitor(C)is however,much improvedoverthe held discharged. Upon application of a standard bipolar 555/6 in that it con- V (GND) - 6v-- (GND) negative pulse trigger topin2,the trolssimultaneously the state of the Fig. 3. Astable operation. voltageacross the capacitor increases OUTPUT and DISCHARGE pins. exponentially. When the voltage across the capacitor equals 2/3 (V+ - V-), the ASTABLE OPERATION comparator resets which discharges the The circuit can be connected as a multi - V (GND) capacitor rapidly and drives the output vibrator. The external capacitor charges to its low state. through RA and R Band discharges TRIGGER through R B only. Thus the duty cycle OUTPUT CONTROL VOLTAGE CONTROL may be preciselyset by the ratio of V 0- - VOLTAGE The CONTROL VOLTAGE terminal these two resistors.Inthis mode of

permits the two trip voltages for the operation, the capacitor charges and dis- OPTIONAL 2 (V' - V ) ISV THRESHOLD and TRIGGER internal charges between 1/3 and 2/3 (V+ - V.). CAPACITOR comparatorsto be controlled.This As in the triggered mode, the charge and V (GND)II TV (GND) provides the possibility of oscillation, dischargetimes, and thereforethe Fig. 4. Monostable operation.

OPERATING CHARACTERISTICS ITA = 25°C, v -v =+2 to +15 Volts unless other SpeCifiedl 8 -PIN DIP VALUE PARAMETER TEST CONDITIONS MIN TYP MAX UNITS Supply Voltage V (GND) V (Vcc) -20°C c TA ,- +70°C 2 18 V -55°C s' TA , .125°C 3 16 V TRIGGER DISCHARGE Supply Current ICM7555 V' -V --- 2V 60 200 0A OUTPUT THRESHOLD (Note 4) V* -V = 18V 120 300 ,,A, RESET CONTROL VOLTAGE Supply Current ICM7556 V. -V= 2V 120 400 ,,A (Note 4) V'Ar= 18V 240 600 A Fig.1. Pinout of the 7555 is identical to that Timing Error RA, Re = 1k to 100k of the NE555. (Note 5) C = 0.1,.F Initial Accuracy 20 % Drill with Temperature 50 ppm/. C WV Drift with Supply VoltageV' -V 5V 1 0 %/Volt

Threshold Voltage 2/3 X(V' -V I TA 25°C Trigger Voltage 1/3 X(V-V- / 400 Trigger Current WA/ = I8V 50 pA V' -V= 5V 10 pA

NP -V= 2V 1 pA 300 Threshold Current V' -V= 18V 50 pA SE/NE555 V -V- = 5V 10 pA V -V= 2V 1 pA 200 Reset Current VRESET = V V -V= 18V 100 pA V' -V- = 5V 20 pA V -V= 2V 2 pA 100 Reset Voltage ICM7555/56 V' -V-= 18V 0 4 0 7 I 0 V V' -V =2V 04 0.7 10 V Control Voltage Lead 2/3 Xur-V- I 0 4- Output Voltage Drop Output Lo II, -V= 18V Isms = 3 2rnA 0 1 0 4 V V --V- = 5V 'Sox = 3 2mA 0.15 0./ V Output Hi V' -V' = 18V 'SOURCE = I OrnA 17.8 17 25 V V' -V' = 5V 'SOURCE = 1 OmA /.0 4 5 V 0 200 400 600 600 Rise Time of Output RL = 10Mohms CL = 7pF V' -V- = 5V 400 TIME -nS nS Fall Tune of Output RL = 10Mohms CL = 7pF V -V- = 5V 40.0 Fig. 2. Power supply transients of the 555 and nS 7555 compared. Guaranteed Max Osc FredAstable Operation 500 kHz

68 Interested in LEDs? See page 69. ETI CANADA-MARCH 1979 I I I I I I I I I r-- 5 New Cheap! Cheap! Cheap! AUTOMOTIVE Paperbacks AUDIO/COMPONENTS.... 1 CHOOSE FROM - I These five books are advertised here for the 1 SONY, KENWOOD, JVC, 0 4 first time in ETI. More details will be publi- I shed in future issues. The books are in stock I SAE, BGW, THORENS, PROXIMITY, now. All 7 1/8 X 4 1/4 inches. ONKYO, DENON, MAXELL, FUJI, SCOTT, TDK, NAKAMICHI, Radio CircuitsUsingICs by Brian Dance JENSEN, CLARION, GRACE, SHURE, Published May 1978. 125 pages. GRADO, STANTON, POLK, AKG, $4.50 + 30$ postage & handling. Mobile Discotheque Handbook SENNHEISER, KLIPSCH, DECCA, by Colin Carson. VHER, AVID, ADS, BOSE, KEF, Published May 1978. 127 pages. DISCNASHER, RG, DBX, AKAI, $4.50 + 304 postage & handling. AUDIO TECHNICA, SHEFFIELD, Popular Electronic Projects by R.A. Penfold GRADO, GUSDORF, EPI, CONCORD, Published July 1978. 135 pages. PHASE LINEAR, $4.80 + 30$ postage & handling. .... AND MANYMANY MORE IC LM3900 Projects by H. Kybett. Published August 1978. 119 pages. Write For: $4.50 + 30$ postage & handling. FREE CATALOGUE AND PRICES Electronic Music and Creative Tape Recording To: ALBERTA AUDIO by M.K. Berry. DIV'N COI LTD. Published July 1978. 87 pages. $4.20 + 304 postage & handling. 1107 - 73rd AVE. S.W. CALGARY, ALBERTA T2V OR9 Pleaseusethe cardtoorder.

AN, AO,MI, MP ANI I AI I, AI II AI I" I, --1 50SimpleLED Circuits By R.N. Soar WITH 64 pages Published December 1977 KESTER SOLDER A Itis suprising how many of our readers do not under- stand these remarkable little devices. This book tells you how to use LEDs how to choose the value of the series resistor howtomake a zero - beat indicator Handymen! Hobbyists! make a constant -current charger DO-IT-YOURSELFERS! Let Kester Solder aid you in your home repairs or hobbies. For that household allkinds oftesters, for item that needs repairing -a radio, TV, model train, jewelry, appliances, minor voltage, current,transis- electrical repairs, plumbing, etc. - Save money - repair it yourself. Soldering tor good/bad, etc. with Kester is a simple, inexpensive way to permanently join two metals. noiseless volume control When you Solder go "First Class" - use Kester Solder. signalling circuit For valuable soldering information send self-addressed stamped envelope to much more Kester for a FREE Copy of "Soldering Simplified". $2.75 + 30$ postage 112.1 KESTER SOLDER COMPANY OF CANADA, LTD. Pleaseusethe cardtoorder. Litton P.O. BOX 474 / BRANTFORD, ONTARIO, CANADA N3T 5N9 III I, II, AEI AEI /I ETI CANADA-MARCH 1979 69 The

Funof .... Elect-

4tf:3. ronics EVER SINCE HE HAD HIS CB LICENSE REVOKED, HARRY'S BEEN ACTING A LITTLE STRANGELY...

I WENT OUT AND BOUGHT ONE OF THOSE SOLD- I THINK I'VE GOTTEN MY SIGNALS CROSSED WITH NASA - ERLESS BREADBOARDS, FRANK, AND IT'S A AND IF I'M RIGHT, MY SCALE MODEL BIPLANE IS RIGHT THIS REAL TIME-SAVER - IT NOW ONLY TAKES ME MOMENT TOUCHING DOWN ON VENUS. HALF AS LONG TO MAKE A WIRING ERROR AND BLOW UP EXPENSIVE PARTS!

AL'S TV REPAIR

0 . . 0 ff//1//1111/1/111,71 I fiilllifrah/i11///

THESE NEW PLUG-IN MODULES ARE A GREAT BOON TO IYESSIREE, JIM, GONE ARE THE OLD DAYS WHEN I USED TO BURN THE SERVICEMAN, SAM, NOW INSTEAD OF CHARGING OUT A $10 METER ABOUT TWICE A WEEK - NOW I'M A SOPHISTI- A CUSTOMER TO REPLACE A 980 TRANSISTOR, WE CAN CATED EXPERIMENTER, AND I ONLY BURN OUT DELICATE EQU- CHARGE THEM $35 FOR A WHOLE NEW MODULE! IPMENT COSTING HUNDREDS OF DOLLARS.

70 Have you seen page 30 yet? Right after page 29. ETI CANADA-MARCH 1979 CLASSIFIED

EQUALIZER Phaser, many other kits; quality components; send 250 for 1979 catalogue. CHIPS ELECTRONICS, Box 848, Oakville, Ont., L6J 5C5.

J & J ELECTRONICS LTD., P O. Box 1437 E, Winnipeg, Manitoba R3C 2Z4 Semiconductor Specialists Do you get our bargain flyers? Send $1.00 to receive the current literature and specials and to be placed on the mailing list for the future publications.

DEALERS Invited! Big Eye high intensity magnifying lamp. Useful for electronic assembly, inspection, hobbies, crafts, lowvisionreading,alldetailwork. Gooseneck table lamp withsuperb, distortion -free, 5 inch magnifying lens attached to shade. Permits use of both eyes and leaves both hands free. CSA certified.U.S.A. product with proven track record. COMMETRICS LTD., P.O. 715,het &yyo(tr:f Box 278, St. Lambert, Que. J4P 3N8. NEW STORE! for the ETI's new classified advertising section allows you to reach 30,000 readers HOBBYISTHAMAUDIOCB'R nation-wide. For as little as $15 (there's a 20 word minimum) you can pro- DIGITAL CLOCK KIT 12/24 HR. mote your business from coast to coast. WITH CASE $29.95 Ont. Res. add 7% sales tax WHAT DO YOU DO? General Electronics Send us your typewritten or clearly printed words, your permanent add- 5511 YONGE ST., WILLOWDALE, ONT. ress and telephone number, and your money (no cash please). Make your 221-6174 cheque or money order payable to 'ETI Magazine'. We're at Unit 6, 25 Overlea Blvd., Toronto, Ontario M4H 1B1. WHAT DO WE DO? AMPLIFIER Kits 120W Stereo with Power We typeset your words (and put the first word and your company name Supply. $78.00 60W Stereo $49 00 in bold capital letters). 20W Stereo with P.S. $33.00 60W Mono $31.00 20W Mono with P.S., Trans- If we get your message by the 14th of the month, it will appear in ETI former $32.00 IC Stereo Pre-Arhp. with 11/2 months later. For example, if we receive it by November 14th, you MicMixer$37.00.Money Back (and thousands. more) will see it in the January issue. Guarantee Free Repair Service Free catalogue:AUDIOVISIONSERVICE P.O. Box: 955, Stn. B, Willowdale, Ont., M2K 2T6. W S I SALES COMPANY SWL RADIOS - HAM RADIOS - PRINTERS: Dot Matrix ASCII I/O 18 SHELDON AVENUE NORTH Terminals - 30 Char/Sec. RS -232 LED Bar Displays, Audio power Ampli- KITCHENER, ONTARIO N2H 3M2 Interface -$800.00 COMBUSLTD.,90 fiers, many other kits; send 25(; for 1979 Telephone (519) 579-0536 Esna Park Dr. #4, Markham, Ontario L3R catalogue. CHIPS ELECTRONICS, Box WRITE FOR GIANT CATALOG 2R7, (416) 495-0109. 848, Oakville, Ont. L6J 5C5. FREE OF COURSE!! (VE3EHC)

ETI CANADA-MARCH 1979 71 ETI Project File

Updates, news, information, ETI gives you project support

PARTS PARTS PARTS PROJECT FILE is our department dealing with Should you find that there are notes you wish to information regarding ETI Projects. Each month read for which you do not have the issue, you may We are continually beseiged with we will publish the Project Chart, any Project Notes obtain them in one of two ways. You can buy ffi-e letters from readers asking where they whicharise, generalProjectConstructor's back issue from us (ref erto Project Chart fordate of can get parts in their area. Since we Information, and some Reader's Letters and issue and see also Reader Service Information on Questions relating to projects. ordering).Alternativelyyou mayobtaina can't take a country -wide tour to photocopy of the note free of charge, so long as check where all the elctronics parts - PROJECT NOTES your request includes a self addressed stamped places are, how about sending us a Since this magazine is largely put together by envelope for us to mail it back to you. Requests note on any stores you have found humans, the occasional error manages to slip by us without SASE will not be answered. into print. In addition variations in component useful, what they are good for (if you characteristics and availability occur, and many PROJECT own the place you can contribute too!) readers write to us about their experiences in CONSTRUCTOR'S and so on. At some time in the future building our projects. This gives us information INFORMATION we would like to help out the "lost" which could be helpful to other readers. Such information will be published in Project File under Useful information on the terminology and readers by publishing a rundown of Project Notes. (Prior to May 78 it was to be found at notation will be published each month in Project where to get what. the end of News Digest.) File.

ISSUE ARTICLE ISSUE ARTICLE DATE DATE Feb 78 Tachomonitor Aug 78 Sound Meter & Neg. ETI Project Apr78 Neg. Dec 78Note: N Feb 78 LCD Panel Meter Aug 78 Porch Light & Neg. Chart Apr 78 Note: C Aug 78 IB Metal Locater & Neg. Apr 78 Neg. Aug 78 Two Chip Siren & Neg. Feb 78 CB Power Supply Sept 78 Audio Oscillator Apr 78 Neg. Nov 78 Neg. May 78 Note: N Sept 78 Shutter Timer Feb 78 Freezer Alarm Nov 78 Neg. Apr 78 Neg. Sept 78 Rain Alarm Canadian Projects Book Mar 78 Hammer Throw Oct 78 CCD Phaser Metal Locator June 78 Neg. Audio Limiter Nov 78 Neg. 5W Stereo Heart -Rate Monitor Feb 79Note:C,D Oct 78 UFO Detector Overled GSR Monitor Mar 78 True RMS Meter Nov 78 Neg. Bass Enhancer Phaser Apr78 Neg. Oct 78 Strobe Idea Modular Disco Fuzz Box Jan 79Note:N Nov 78 Cap Meter &Neg. G P Preamp Touch Organ Feb 79Note:N Nov 78 Stars & Dots Bal. Mic. Preamp Mastermind Mar 78 Ceramic Cartridge PreampDouble Dice Home Burglar Alarm Nov 78 CMOS Preamp & Neg. Reaction Tester Apr 78 Computer PSU & Neg. Mixer & PSU Dec 78 Digital Anemometer VU Meter Circuit Sound -Light Flash Apr 78 Audio Delay Line & Neg. Feb 79Neg Headphone Amp Burglar Alarm Apr 78 Gas Alarm & Neg. Mar 79Note:C. D 50W -100W Amp Injector -Tracer May 78 White Line Follower Dec 78 Tape Noise Elim Note: N Apr. 78 Digital Voltmeter June 78Neg. Feb 79 Neg May 78 Acoustic Feedback Eliminator Dec 78 EPROM Programmer June 78Neg. Feb 79 Neg Key to Project Notes May 78 Add-on FM Tuner C:- PCB or component layout Jan 79 Log Exp Convert. D:- Circuit diagram June 78 Neg. Feb 79Neg N:- Parts Numbers, Specs June 78 Audio Analyser Digital Tach. Neg:- Negative of PCB pattern printed June 78 Ultrasonic Switch & Neg. Jan 79 0:- Other June 78 Phone Bell Extender & Neg. Feb 79 Neg 5:- Parts Supply July 78 Proximity Switch Jan 79 FM Transmitter T:- Text Aug 78 Neg. Feb 79 Neg U:- Update, Improvement, Mods July 78 Real Time Analyser MK II (LED) Feb 79 Phasemeter & Neg ':- Notes for this project of complicated Aug 78 Neg. .iature, write for details (enclose S.A.S.E., see Feb 79 SW Radio text) July 78 Acc. Beat Metronome. Feb 79 Light Chaser & Neg Aug 78 Neg. Mar 79 Tape -Slide Synch July 78 Race Track Mar 79 Synth. Sequ. Aug 78 Neg. Mar 79 Dual Dice 72 ETI CANADA-MARCH 1979 ETI Project File

PROJECT CHART Firstlydecimalpointsaredropped and Digital Anemometer This chart is an index to all information available substituted with the multiplier, thus4.7uF is written relating to each project we have published in the 4u7. Capacitors also use the multiplier nano (one This project appeared in our Decem- preceding year. It guides you to where you willfind nanofarad is 1000p F). Thus 0.1 uF is 100n,5600pF is ber1978issue. The printedcircuit the article itself, and keeps you informed on any 5n6. Other examples are 5.6pF = 5p6, 0.5pF = Op5. boardis Resistors are treated similarly: 1.8M ohms is correct where there are two notes that come up on a particular project you are errors in the circuit diagram. Pin 16 interested in.It also gives you an idea of the 1M8, 56k ohms is 56k, 4,7k ohms is 4k7,100 ohms is importance of the notes, in case you do not havethe 100R, 5.6 ohms is 5R6. of DSP 1(connected to pin 11, DSP 2) issue refered to on hand. should be labeled pin 6, and pin 7 DSP1 Every few months we print a pull out section in Kits, PCBs, and Parts should be shown connected to pin 9 of themagazinewhich maybeused as a We do not supply parts, for our projects, these DSP 2.Gail would like everyone to photographic negative for making printed circuit must be obtained from component suppliers. boards (as described in our January 78 issue). However, in order to make things easier we co- know that it was not her fault. Each edition of this sheet contains projects from operate with various companies to enable them to the preceding few issues. Information on where to promptly supply kits, printed circuit boards and find which negative is included in the chart. unusual or hard -to -find parts. Prospective builders should consult the advertisements inETI for Write to: Project File suppliers for current and past projects. Electronics Today International Any company interested in participating in the Unit 6, 25 Overlea Blvd., supply of kits, pcbs or parts should write to us on TORONTO, Ontario their letterhead for complete information. M4H 1B1 READER'S LETTERS AND Component Notations QUESTIONS We obviously cannot troubleshootthe individual and Units reader's projects, by letter or in person, so if you We normallyspecify components usingan have a query we can only answer it to the extent of international standard. Many readers willbe clearing up ambiguities, and providing Project unfamiliar with this but it'ssimple, less likely to lead Notes where appropriate. If you desire a reply to to error and will be widely used sooner or later. ETI your letterit must be accompanied by a self has opted for sooner! addressed stamped envelope. Please mention ETI when responding to advertisements.

um um miINEHNIN eti PANEL TRANSFERS

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ETI CANADA-MARCH 1979 73 Reader

Service Sell ETI 1977 1978 1979 ETI isavailableforresaleby February January January Information component stores. We can offer a good May February February discount and quite a big bonus, the June March chances are customers buying the July .6111.1. magazine will come back to you to Du y September May Editorial Queries theircomponents.Readers having November June trouble getting their copy of ETI could July Written queries can only be answered suggesttotheir component store August when accompanied by a self-addressed, manager that he should stock the September stamped enveloped, and the reply can magazine. October take up to three weeks. These must November relate to recent articles and not involve December ETI staff in any research. Mark your Back Issues and letter ETI Query. Photocopies We can supply photocopies of any Projects, Components, Previous issues of ETI-Canada are article published in ETI-Canada, for available direct from our office for which the charge is $1.00 per article, Notation $2.00 each. Please specify issue by the regardless of length. Please specify month, not by the features you require. issue and For information on these subjects article.(A special con- The following back issues arestill siderationappliestoerratafor please see our Project File section. available for sale. projects, see Project File.) LIABILITY: Whilst every effort has been made to ensure that all constructional projects referred to in this edition wilt operate as indicated efficiently and properly and that all necessary components to manufacture the same will be available, no responsibility whatsoever is accepted in respect of the failure for any reason at all of the project to operate effectively whether due to any fault in design or otherwise and no responsibility is accepted for or at all the failure to obtain any component parts in respect of any such project. Furtherno responsibility is accepted in respect of any injury or damage caused by any fault in the design ofany such project as aforesaid

FOR THE LONG, MED OR SHORT HAUL... Advertisers' Index it's the S". ESPECIALLY' LI new DESIGNED (7 A.P. Products LONG c FOR A 36 Allan Crawford Associates 6 MED ADJUSTABLE 4-", VACUUM STROKE Alpha Tuner Service SHORT 54 USI4O Castle Tuner Service 58 Ceres 13 UIMOV-EgaL, Classifieds 71 Compumart 30 5'qedfLii(0,q; Dominion Radio & Electronics 13 Compact tool for convenient tool GTE Sylvania 76 box storage.Precision molded Jana Electronics plastic barrel and low -mass 66,67 plunger creates rapid vacuum Joy of Sound 69 impulse with negligiblerecoil. Kester Solder 69 Three position plunger adjusts loading span to fit large or small Len Finkler 12,74 hands. Ample vacuum for most Metermaster 73 circuit board desoldering require- ments. McGraw-Hill 75 Omnitronix 35,40 Write for complete H. Rogers Electronic Instruments Edsyn catalogue 29 Walgram Publishing 55 len finkler ltd Zenith Radio 56 25 Toro Road, Downsview, Ontario M3J 2A6 telephone 630-9103 telex 065-24010

74 ETI CANADA-MARCH 1979 Everibody's. makingmoney se mg microcomputers. Somebody goingto makemoney servicing them. New NRI Home Study Course Shows You How to Make Money Servicing, Repairing, and Programming Personal and Small Business Computers Seems like every time you turn around, somebody comes along with a new computer for home or business use. And they're being gobbled up to handle things like payrolls, billing, inventory, and other jobs for businesses of every size...to perform household functions like budgeting, envi- ronmental systems control, indexing recipes, even playing games. Growing Demand for Computer Technicians...Learn in Your Spare Time Even before the microprocessor burst upon the scene, the computer industry fore- cast over a 100% increase in job openings for the decade through 1985. Most of them new jobs created by the expanding world of the computer. NRI can train you at home to service both microcomputers and their big brothers. itain you at your convenience, with clearly written "bite -size" lessons that you do evenings or weekends without quit- ting your present job. No Experience Needed meaningful experiments building and You don't need prior training in elec- Rush Card for Free Catalog studying circuits on the NRI Discovery tronics or computers to take this exciting Send the postage -paid card today Lab.Then you build your own test in- new course. NRI starts you with the basics, for our 100 -page, full -color catalog. It de- struments like a transistorized volt -ohm gives you a firm foundation to build on. And scribes NRI's new Microcomputer lechnology meter, CMOS digital frequency counter your personal counselor is always available, Course in detail, shows all equipment, kits, ...equipment you learn on, use later in ready to help whenever you have questions. and lesson plans. And it also tells about your work. other NRI courses... Complete Communica- Assemble Your Own And you build your own microcom- tions with 2 -meter transceiver...TV/Audio/ Microcomputer puter, the only one designed for learning. It Video Systems Servicing with training on NRI training also includes plenty looks and operates like the finest of its kind, the only designed -for -learning 25" diagonal of practical experience. You perform actually does more than many commercial color Tv with state-of-the-art computer units. But NRI engineers have designed programming. With more than a million components aid planned assembly so it students since 1914, NRI knows how to give demonstt..tes important principles, givesyou the most in home training for new you wonting experience in detecting opportunity. If card has been removed, and correcting problems. It's the kind write to: of "hands-on" training you need to repair and service units now on the NRI Schools market. McGraw-Hill Continuing NRI Education Center 330 Progress Avenue Scarborough, Ontario M1P 2Z5 or telephone 416-293-1911 SYLVANIAC.B. MARINE PRODUCTS The Sylvania 5/8" wave Marine antennas are ideal for use on all water craft, fiberglass sports cars and other recreational craft. 4', 6' and 8' models give you your choice for a wide variety of applications. 2035 4' 5/8" WAVE Base matched snap -in mount assembly. 2040 4' 5/8" WAVE Whip, coax cable, matching harness. 3/8"-24 stud mount. Rachet mount included. 2045 6' 5/8" WAVE Same as Model 2040. 2050 8' 5/8" WAVE 2 pcs.-Same as Models 2040-2045. 2055 17' 2PCS. MARINEFull base station antenna for pleasure craft. Rugged construction.Complete with rachet mount, stand-off bracket and 6' cable assembly. 2060 4' 5/8" WAVE 6' matching harness with sailboat or bulkhead bracket. 2065 6' 5/8" WAVE Same as Model 2060 3050 MULTI -PURPOSE RACHET MOUNT Stainless steel hardware. Tough ABS plastic. 3051 HEAVY DUTY RACHET MOUNT 1--14 thread.Stainless steel hardware.Tough polycarbonate mount. 3052 SIDE BRACKET MOUNT Clamps 1" orl'-(2" mast to bulkhead. Tough ABS plastic.Stainless steel hardware. 3053 SAILBOAT BRACKET Stainless steel hardware.

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for full particulars - phone or write: GTE Sylvania Canada Limited Electronic Components I 8750 Cote de Liesse Road SYLVANIA and Systems Montreal, Quebec H 4T 1H3 (514) 735.4201 Telex 05-825884