Popular Electronics Build a Subwoofer Let Your Home Theater Roar and Rumble

PRIMESTAR. THE DBS ALTERNATIVE Popular Electronics Build A Subwoofer Let your home theater roar and rumble

The Truth About Speaker Cables What's really inside those expensive audiophile cables?

Designing Speaker Crossovers Create your own great -sounding speakers d SBk'BDCCH.xux.xx 5-DIGIT 60506 Random -at Image k6O506C+HM997GA006M FEB96 P73 Make 3 -D images that pop o ROBERT RAHM RESP of your computer's screen 116 997 GRAND AUE AURORA IL 60506 -2513 $3.50: U.S. $3.95 CAN. FrJEL1t;Aricarí

www.americanradiohistory.comAmericanRadioHistory.Com MIXED-MODE POWER Design & Verify Faster with Electronics Workbench®

More Power s Simulate bigger and more Electronic complex circuits. Faster. On average, Electronics Analog, Digital & e nch Workbench Version 4 is o rb more than 5 times faster l compbner Mixed Circuits in a lab than Version 3. Electronics Workbench" The electronics Version 4 is a fully integrated schematic capture, simulator and graphical waveform More Parts generator. It is simple to Multiple parts bins mix analog and digital parts contain over twice the in any combination. components of Version 3. Design and Verify Circuits... Fast! More Models Electronics Workbench s Over 350 real world analog simple, direct interface and digital models are helps you build circuits included free with in a fraction of the time. Electronics Workbench. Try `what if' scenarios and And, if you need more, an fine tune your designs additional 2,0(X) models painlessly. are available.

Electronics Workbench delivers the power you need to design and verify analog, digital and true mixed mode circuits. Over 20,000 customers have already put Electronics Workbench to the test. The result: Better designs... Faster. And over 90% would recommend it to their colleagues. Electronics Workbench will save you time and money. We guarantee it.*

= Electronics Workbench Elle Edit ,"Ircuit Window tjelp Call Nov: 800-263 -5552 ® 3® i3C- mS 01=t w4 02,u;A' a nrO Just $299+s;H Foi Windows, DOS or Macintosh CI Active 1 r- 1 * 0 I©1!E A *30 day money-back guarantee Bpi Free unlimited technical support alma *}f Jall- IliizS. mm Yes, in Electronics i e I'm interested Workbench. BC . .:e_r. .i lido ® t.rfli. L DGC " ... olrNmizNon: I' GROUND . Addrtas'.

1UI T N[ 'fl E TRIGGER 4 EDGE Phone' Po® LEVEL. IIII I ® I t)rcrer to raint. Ils dVFacc at: D'.7 l'}I ¡ 6/r1 /9 fl, B EXT^ tc tul tnt I I \ CNflteO l fl CNPNN t ' 9EA1FE2 INTERACTIVE IMAGE TECHNOLOGIES LTD. Y PO®^POY V Pos c, 11C: 4g. ^' AC 4 -- 908 Niagara Falls Blvd. #068, North Tonawanda, NY 14120-2060 .i..-.. el] It CO Telephone: 41E977 -5550 FAX: 416 -977 -1818 True mixed -mode simulation Simultaneous AM transmission, ' E-mail: [email protected] digitization and pulse-code modulation of a signal. CompuServe: 71333,3435 BBS: 416 -977 -3540 INTERACTIVE Trademarks are property of their respective holders. 'Offer is in U.S. dollar. and valid only in the Urited States and Canada.

Ausual'ra:2-5t9 - 933 Bra7il:11453558S Cypnri:262- I0Xí:i I eimtai ::33-250109 Nitwit!: 0-297-5033 Frame: 14-Xkiitl1 0 (ìt 1 iiht 11 -62- k) Greece: I -52í- Yi1 Flungury: I- 215-6bí2 India: I I í 11-13,i3 Israel: 3647 -5(313 Italy: t1- 337 -554) Japan: 33382 -3136 Malaysia: ì-".í -21ía Mexi x.i(P,5 Netherlands: tsom-766 i' w l.ealnd 9.267 -1756 Norway: 2- 1([7045 Iiautl;.0: txl t-da M)

Singapoi :462.0006 Slovenia:6 1- 3 1 743311 Souci Africk: 33114430)9 South Korea: 2 -2 -222 -3431 Spain: l- 553-3234 Sri L tnka: 1 86 -597n Sweden:S740-551X) Thailand 6(.2-3áìL952 UK: 21rá.23 -3216 CIRCLE 114 ON FREE INFORMATION CARD

www.americanradiohistory.comAmericanRadioHistory.Com JULY 1995 Popular Electronics Vol. 12, No. 7 A GERNSBACK PUBLICATION

C O N S T R U C T I O N

43 Build a Subwoofer Is something missing from your home -theater or audio system? Give it the bass oomph it needs to make music and movies really rumble and roll - William R. Hoffman

60 Build a Telephone- Wiring Tester Test all types of telephone cable, jacks, and more; you can even test items while they are still connected to the telephone system - Christopher Zguris Page 9 63 Build the Galviamp It's two valuable test aids -a galvanometer and a variable -gain amplifier -in one handy device -Joseph J. Carr

F E A T U R E S

37 Designing Loudspeaker Crossovers Create your own great- sounding speaker designs with these easy - to -use computer programs - William R. Hoffman

46 The Truth about Speaker Cables Page 43 What's inside those expensive audiophile cables that makes them cost so much? Are they worth the money? Learn the answer to the first question in this article, and use that information to answer the second one for yourself- William R. Hoffman

49 Fun with Random -Dot Images Make them yourself on a PC, but don't go blind! -Marc Spiwak

54 ... And The Bananas were Green: The Early Days of Color TV The road to the color TV we enjoy today was far from smooth - Page 49 James P. Rybak

POPULAR ELECTRONICS (ISSN 1042-170-X) Published monthly by Gernsback Publications. Inc 500 -B Bi- County Boulevard. Farmingdale, NY 11735. Second - Class postage paid at Farmingdale, NY and at DdditionaI mailing offices. One -year, twelve issues, subscription rate US. and possessions $2195, Canada $2884 (includes G.S.T Canadian Goods and Services Tax Registration No. R125166280}, all other countries $29.45. Subscription orders payable in U.S funds only, International Postal Money Order or check drawn on a U.S bank. U.S. single copy price $3.50. Copyright 1995 by Gensback Publications, Inc All rights reserved. Hands -on Electronics and Gizmo trademarks are registered in U.S. and Canada by Gernsback Publications, Inc. Popular Electronics trademark is registered in U.S. and Canada by Electronics Technology Today. Inc. and is licensed to Gernsback Publications. Inc. Printed in U S.A.

Postmaster: Please send address changes to Popular Electronics, Subscription Dept., P.O. Box 338, Mount Morris. IL 61054 -9932

A stamped self- addressed envelope must accompany all submitted manuscripts and /or artwork or photographs if their return is desired should they be rejected. We disclaim any responsibility for the loss or damage of manuscripts and /or artwork or photographs while in our possession or otherwise.

As a service to readers, Popular Electronics publishes available plans or information relating to newsworthy products, techniques and scientific and technological developments. Because of possible variances in the quality and condition of materials and workmanship used by readers, Popula- Electronics dis- claims any responsibility for the safe and proper functioning of reader -built projects based upon or from plans or information published in this magazine. 1

www.americanradiohistory.comAmericanRadioHistory.Com J U L Y 1 9 9 5

Larry Steckler, EHF, CET, P R D U C T R E V I E S O W editor -in -chief and publisher 9 Gizmo EDITORIAL DEPARTMENT Carl Caron, editor A look at the Primestar DBS system, plus BeeperKid child- monitor- Dan Karagiannis, associate editor Plus Radio Shack ing system, WinNet internet- access software, Teri Scaduto, assistant editor Personal Emergency Phone Dialer, and lots more Evelyn Rose, editorial assistant Marc Spiwak, editorial associate Joseph J. Corr, K4IPV, 28 Hands -On- Report contributing editor Media Vision Reno portable CD -ROM player Marc Ellis, contributing editor Jeffrey K. Holtzman, contributing editor C O L U M N S Don Jensen, contributing editor Charles D. Rakes, contributing editor 24 Multimedia Watch Marc Saxon, contributing editor Two big games, and more -Marc Spiwak John Yacono, contributing editor

PRODUCTION DEPARTMENT 30 Think Tank Ruby M. Yee, production director More comments from our readers Yacono -John Karen S. Brown, production manager 68 Antique Radio Kathy Campbell, production assistant Putting the Minerva Tropicmaster back together -Marc Ellis ART DEPARTMENT 74 Computer Bits Andre Duzant, art director Russell C. Truelson, illustrator Soldering irons and cyber circuits -Jeff Holtzman

Jacqueline P. Cheeseboro, 78 Circuit Circus circulation director Using a voice -storage chip- Charles D. Rakes Michele Torrillo, POPULAR ELECTRONICS bookstore 82 DX Listening BUSINESS AND EDITORIAL Fun in the summertime -Don Jensen OFFICES Gernsback Publications, Inc 500 -8 Bi- County Blvd, 84 Ham Radio Farmingdale. NY 11735 All about selectivity- Joseph J Carr 1 -516- 293 -3000

FAX: 1 -516- 293 -3115 President: Larry Steckler

86 Scanner Scene SUBSCRIPTION Up in the air -Marc Saxon CUSTOMER SERVICE/ ORDER ENTRY 1- 800 -827 -0383

AM - PM EST D E P A R T M E N T S 7:30 8:30 Advertising Sales Offices listed on page 134 3 Editorial Composition by Motes Graphics 4 Letters Cover by Loewy Design 6 New Products Cover Illustration by Tim McGarvey 76 Electronics Market Place ABC AUDITED 88 Electronics Library Since some of the equipment and circuitry described in POPULAR ELECTRONICS 95 Popular Electronics Market Center may relate to or be covered by U S. patents, POPULAR ELECTRONICS dis- 134 Advertiser's Index claims any liability for the infringement of such patents by the making, using, or selling of such equipment or circuitry, 135 Free Information Card and suggests that anyone interested in such projects consult a potent attorney. 2

www.americanradiohistory.comAmericanRadioHistory.Com E A R N Y O U R EDITORIAL B.S. DEGREE IN A DBS ALTERNATIVE COMPUTERS OR Regular readers of my editorials might recall that earlier this year I dumped my cable service in favor of the DSS direct - ELECTRONICS broadcast satellite (DBS) system (see Editorial, February and March 1995). I've had the system for a while now, and I am as happy with it as I was the day I got it.

But that's not what we are going to talk about this month. Instead, we are going to turn our attention to another DBS system -Primestar. For those not familiar with it, Primestar was actually the first digtal DBS service provider, and while DSS has, at least for the time being, passed it in size, A Primestar has also shown dramatic growth over the past By at Home year. Studying Grantham College of Engineering, Primestar and DSS probably have more in common than now in our 45th year, is highly experienced in "distance education"- teaching like but there are also some either would to admit, by correspondence- through printed significant differences. Those differences might make one materials, computer materials, fax, or the other more suitable for your needs. modem, and phone. No commuting to class. Study at your own pace, while continuing on your The most glaring difference, and perhaps Primestar's chief present job. Learn from easy -to- advantage, is initial cost. If you want DSS, you must buy the understand but complete and thorough hardware, then either pay for installation or install it lesson materials, with additional help from our instructors. yourself. With Primestar, you pay only an installation charge Our Engineering Technology B.S. that varies by location. The installation charge is required Degree Program is available in either of because Primestar does not allow consumers to install the two options: equipment themselves. (1) The B.S.E.T. with Major Em- phasis in Electronics, OR (2) The B.S.E.T. with Major Em- On the negative side of the ledger, Primestar's monthly fee phasis in Computers. for programming (which includes a charge for equipment Our Computer Science B.S. Degree to the B.S.C.S. rental) is slightly higher than that of DSS, and the service Program leads -the Bachelor of Science in Computer Science. offers significantly fewer channels. Then again, Primestar's An important part of being pre- 70 channels might be more than enough for you! pared to move up is holding the right college degree, and the absolutely necessary part is knowing your field. In any event, if you are considering going the DBS route, Grantham can help you both ways -to Primestar represents a viable, and often more -practical learn more and to earn your degree in alternative for many. This month, our Gizmo section takes a the process. closer look at the Primestar system. Discussed are its Write or phone for our free catalog. Toll free, 1- 800 -955 -2527, or see The strengths, weaknesses, costs, and much more. story mailing address below. begins on page 9. Accredited by the Accrediting Commission of the Distance Education and Training Council GRANTHAM a Carl Laron College of Engineering ÿ Editor Grantham College Road Slidell, LA 70460 3

www.americanradiohistory.comAmericanRadioHistory.Com SQUARE -WAVE CORRECTION LETTERS I am writing in regard to Joseph Carr's article, "Making Square Waves at Home" (Popular Electronics, March 1995). Mr. vertical graticule lines at 3 kHz, across the zero axis has no DC extremely interesting, but a ma- Carr says that a square wave 5 kHz, 7 kHz, etc. component. jor protection -failure mode was contains "only even -order har- I have subscribed to many 2. A waveform with half -wave completely ignored. monics." That is contrary to electronics publications over the symmetry (such as a square When the main high- current everything that I learned when I past 40 years, including Popu- wave) has no even harmonics. series -pass transistor, 01, de- got my engineering degree. My lar Electronics, and have from 3. In a waveform with quarter- velops a collector-to- emitter training was that square waves time to time noticed some minor wave symmetry, but not neces- short, essentially all of the reg- were composed mainly of odd - errors. To state that square sarily half -wave symmetry, any ulator input voltage will be order harmonics, while even - waves are composed of even - odd-order harmonics present passed on to the output termi- order harmonics produced tri- order harmonics is more than a are in phase with the fundamen- nals. The over -voltage has the angular waveforms. Other minor error-it's just plain tal. capability of doing great harm to engineers in my work group are wrong. Sorry about the error - the connected load if, for exam- in agreement that this is still B.R. JOSEPH CARR ple, it was 5 -volt logic circuitry. true. Sunnyvale, CA The cute cartoon depicting a To test this theory, I checked mechanical crowbar removing the signal on an HP3585B low - You are correct, and my article SORRY, WRONG the power cord from the wall frequency spectrum analyzer is wrong: Square waves are NUMBER outlet is not true for the case with the HP3325B synthesis/ made up of odd -order There was an error made in the described in Mr. Kaliangile's arti- function generator as the harmonics (3f, 5f, ...), not even - phone number listed for re- cle. A true crowbar circuit will square -wave source. The test order (2f, 4f, ...) as stated. What questing Jensen Electronics' prevent over-voltage damage to frequency was 1 kHz, and the bothers me the most about the catalog (Popular Electronics, the load. When Q1 develops an spectrum analyzer was set to a mistake is that I've known the Electronics Library, March emitter -load short, a true start frequency of 1 kHz and a correct information since high 1995). The correct number for crowbar circuit will blow either a stop frequency of 21 kHz. Sure school (late 1950s). phone requests is primary circuit fuse or a second- enough, the peaks of the dis- The general rules are: 1- 800-426 -1194. We're sorry for ary fuse-a small price to pay played signal were on the 1. A waveform with symmetry any inconvenience that this may for not damaging the load. have caused.-Editor The case in which the load represents a short on the power $20 MINIMUM supply is only one of the protec- NU-TEK "

www.americanradiohistory.comAmericanRadioHistory.Com Obtain required certification... Give yourself the competitive edge it takes to suc- Enhance your career potential... ceed in the expanding world of communications. For Improve your earning power... the first time ever, McGraw -Hill offers you the opportunity to thoroughly prepare yourself to pass the difficult tests required for licensing and certification by Prepare Yourself major sponsoring organizations. Use Communications Licensing and Certification Examinations The Complete TAB Reference to "prep" to Pass The yourself in a wide range of electronics subjects and concentrate on the areas where you need to "brush up." Practice Tests for Communications Licensing and Communications Certification Examinations provides you with full- length practice tests that cover virtually every subject needed to Licensing and master the actual test. Answers let you focus on your weak points and improve your overall knowledge. Much more than just a textbook, this set provides a Certification Exams! focused review of the material you need to know. Fill out and return the coupon, or call, toll -free 1- 800 -822 -8158 - now - for this extraordinary study 'tics reference set. OKoats IC1N COMMU N lcA LIcE rI o N S LICENSINGR Nfl S CERTIFICATIONNSING AND

COi ¡RENCERIsse N SOa old losePh a REFERENCE

ISFCcal Sam Wilson E1A and Joseph 2 -Pi00K Ris-e SE1 ONLY FCC Cf $69 .9. ETA tand iplu, 51i SO taci applicable sale,

Get a TAB Electronics brief l ;ii TAB Electronics The P.O. Box 182606

bag, absolutely free! Aur tyElectrelics Columbus, OH 43271 -3033

Satisfaction Absolutely Guaranteed YES! Please rush my 2- volume set ( #587064 -9). Payment We're so sure that you'll be satisfied with your selection, of $69.90 (plus $6 S &H and applicable sales tax) is enclosed.

it. I we'll even pay the postage if you decide to return I understand that if I purchase this se: now, will receive a TAB Electronics brief bag, absolutely free. PAYMENT METHOD:

[ ] Check or Money Order Enclosed ] Pease charge my credit card: Name [][][]o-[] Address Account No. City State Expiration Date Zip Phone Signature Key= FOR FASTEST RESPONSE CALL VOLL- FREE,1800 822 -8158, 24 hours a day! SP75PEA 5

www.americanradiohistory.comAmericanRadioHistory.Com NEW PRODUCTS

ACIs Trident TR4500 pulls in be loaded and saved, and ac- broadcast frequencies from the tive frequencies to be stored. shortwave bands through the And, when used with a comput- microwave -range public- service er, the TR4500 effectively bands -from below AM broad- becomes a storage spectrum cast to 1.300 GHz -and can be analyzer. An MS -DOS "comm" controlled via a personal com- program is included. puter. Users can tune in to The desktop scanner mea- practically every type of voice sures just 21/4 x 55/8 x 61/2 inches. broadcast from around the It comes with a 12 -volt DC cord, world, including the broadcast, an AC adaptor, an earphone, a world -band, and civil and mili- flexible antenna, software, and tary aviation frequencies found operating instructions that in- Full- Spectrum in AM mode; police fire, and clude a listing of allocated uses nel hi -fi amplifier. Key features emergency services in Narrow for all frequencies covered by include switchable subwoofer Desktop FM; radio and TV -audio broad- the unit. output or headphone output, casts in Wide FM; and even The TR4500 desktop scanner polyolefin cabinet material to Scanner single sideband for transo- with computer interface has a dampen internal resonances, ceanic aircraft and ship suggested retail price of $849; automatic turn on /off, and an communications. the street price is expected to acoustically efficient design for be under $500. For more infor- loud sound levels. mation, contact ACI; The Media 3 (pictured here) Tel. 1- 800 -445 -7717 or and Media 4 multimedia speak- 317 -849 -2570; ers have suggested retail prices Fax: 1- 800 -448 -1084 or of $199 /pair and $299 /pair, re- 317-849 -8794. spectively. For more information, CIRCLE 100 ON FREE contact JBL Consumer Prod- INFORMATION CARD ucts, Multimedia Division, 80 Crossways Park West, MULTIMEDIA Woodbury, NY 11797; SPEAKERS Tel. 516 -496-3400. CIRCLE 101 ON FREE Although many of today's per- INFORMATION CARD sonal computers are equipped with a -ROM CD drive and FIELDPACK WITH sound card, the built-in speak- "STICK" DMM ers are usually inadequate. The Desired frequencies can be Media 3 and Media 4 speakers The HS24K11 Fieldpack from selected directly using the key- from JBL Consumer Products Fieldpiece Instruments consists pad, or the unit can be set to address the needs of PC users of a leather holster that holds a search through all active chan- seeking to enhance their multi- heavy -duty HS24 "stick" digital nels. The user can store any media experiences in learning, multimeter along with a 300 - interesting frequencies in any of entertainment, and game -play- amp current clamp head, deluxe 2016 permanent memory loca- ing. test leads, two short and two tions. Up to 16 different search The Media 3 powered speak - long probe tips, and one al- ranges can be set into memory. er incorporates a 4 -inch woofer ligator ground clip. All the Tuning increments can be se- and a 1.5 -inch tweeter with a accessories are modular, using lected in steps as low as 5000 seven-watt -per -channel hi -fi am- standard banana plugs and cycles. The TR4500 will scan plifier. Subwoofer output allows jacks for connections. through memorized frequencies the system to be further up- at up to 36 channels per sec- graded, dual inputs ond, and will lock on active calls accommodate a second audio to receive the broadcast. The source, and a headphone jack user can listen through the built - provides private listening. The in speaker or use the supplied Media 3 speakers also feature headphone. separate bass and treble con- With the TR4500 connected trols and automatic power to a PC's serial interface, the on /off. computer can be used to set The Media 4 incorporates a Specifically designed for field - the search ranges. The comput- five -inch woofer, a one -inch service use, the leather holster 6 er allows various frequencies to tweeter, and a 10- watt- per -chan- holds the meter and test leads

www.americanradiohistory.comAmericanRadioHistory.Com on the inside and has loops for agnostics for troubleshooting, LOW -PASS FILTERS the current clamp head and technical support, and system Intended for amateur -radio use, long probe tips on the outside. administration purposes. two low -pass filters from Tucker A belt loop on the back allows The MT283LT PCMCIA Electronics are designed to pro- easy carrying. modem costs $399. For addi- vide protection from TVI. The The HS24 meter offers the 12 tional information, contact Multi - T-100 the T-150 each use a most popular ranges for field Tech Systems, Inc., Tel. and 9 -pole Chebyshev filter. They service and will withstand 800-328 -9717 or 612 -785 -3500. operate from MHz and steady -state voltages up to CIRCLE 103 ON FREE 0-30 INFORMATION CARD provide 70 -dB or more of at- 1000 -volts DC and 750 -volts tenuation at 40 MHz and above. AC. It measures volts, ohms, PERSONAL POCKET The filters' impedance is 52 continuity, capacitance, and AC package, or to a TV or VCR DIGITAL MULTIMETERS ohms, and VSWR is less than current (with the included cur- using a video cable. The semiconductor 1.5:1 throughout their passband. rent clamp). A HOLD button The Model 380933 3200 -count, camera's The T-100 will handle 1500 freezes the display to make autoranging, digital multimeter memory can hold up to 96 color watts continuously. The T-150 is one -handed testing easy. Its from Extech Instruments offers still images that can be added The the first 2500 -watt continuous Valox plastic case withstands high- resolution, bar -graph dis- or deleted at any time. lens with mac- low -pass filter for amateur-radio drops up to 10 feet, "O" -ring play, function indicators, data fixed -focal -length use. Each carries a one -year seals protect against con- hold, diode test, and an audible ro positioning allows point -and- The warranty and a 30 -day no -ques- taminants, and metal -oxide conlinuity checker. It measures shoot picture taking. cam- high -speed tions -asked return policy. varistors (MOVs) protect against DC voltage from 300 mV to 450 era also Features a The T-100 T-150 low-pass voltage transients. An audible volts, AC voltage from 3 to 450 (1/8 to 1/4000- second) shutter, and 1/5 CCD element, and ap- filters have list prices of $49.95 beeper and a blinking red LED volts, and resistance from 300 -inch and $109.95, respectively. For warn of voltages over 28 volts, ohms to 30 megohms. The dig- erture- priority automatic system. additional information, contact even if the meter is set to the ital multimeter weighs just 3.4 exposure Tucker Electronics Company, wrong range or function. ounces and measures The 0V -10 LCD digital cam- 1717 Reserve Garland, The heavy -duty HS24K11 4.8 x 3 x 0.8 inches. era has a suggested retail price Street, TX 75042 -7621; Tel. Fieldpack costs $159. For more of $700. For further information, in Texas: information, contact Fieldpiece contact Casio, Inc., 570 Mt. 1-800-527-4642; Dover, NJ 214- 348 -8800; Instruments, 231 East Imperial Pleasant Avenue, Fax: 214-348-0367. Highway, Suite 250, Fullerton, 07801; Tel. 201 -361 -5400. CIFCLE 105 ON FREE CIRCLE 106 ON FREE CA 92635; Tel. 714- 992 -1239; INFORMATION CARD INFORMATION CARD Fax: 714- 992 -6541. CIRCLE 102 ON FREE INFORMATION CARD

PCMCIA MODEM The MT2834LT PCMCIA modem features a patent -pending "CoolJax" duplex phone The Model 380933 pocket - connector, eliminating the need sized digital multimeter, com- national Electronic Wholesalers for messy cables. The modem plete with a wallet -style carrying is compliant with the recently case, test leads, 1.5 -volt bat- adopted ITU standard for 28.8 - teries, and a user's manual, kilobyte per second, V.34 mod- costs $39. A 2000 -count, man- CHIPS ems, and also supports all lower ual- ranging version (Model 380929), which features a lamer display, 200 -mA range, Jerrold Compatible indication, data hold, continuity DP5,DPV5....as low as $5.00 ana diode test, costs $25. For further information, contact Ex- DP7, DPV7 ..as low as $7.00 tech Instruments, 335 Bear Hill Road, Waltham, MA R2F VS, CFI modules from $15.00 02154 -1020; Tel. 617 -7440; Fax: 617 -890 -7864. Atlanta CIRCLE 104 ON FREE Scientific INFORMATION CARD speed standards. It is designed Quick- Boards for: for use in standard Type II with 8570, 8580, 8590, 8600 PCMCIA slots, and comes DIGITAL STILL CAMERA 8550, MultiExpress fax and data communications software for Casio's QV-10 handheld digital all as low as $14.75 The MT2834LT uses still camera allows you to view Windows. ALSO AVAILABLE FOR TOCOM, PIONEER AND ZENITH industry- standard "AT" com- images as they are shot, thanks mands for modem configuration to a high -resolution, active -ma- and dialing, and includes a re- trix. 1.8 -inch color LCD screen. mote configuration feature that The images can then be trans- allows the user to remotely ferred to a personal computer optional transfer 1. 7 run di- by using an 800.639.6369 change parameters and CIRCLE 167 ON FREE INFORMATION CARD

www.americanradiohistory.comAmericanRadioHistory.Com TECHNOLOGY UPDATE

Unlimited extensions -no monthly charge. Most phone lines can only handle up to five extensions with regular phone jacks. Not with the Wireless Phone Jack. All you New device turns any need is one transmitter, and you can add as many receivers as you want. Six, ten, there's electrical outlet into no limit. And with the Wireless Phone Jack, you'll never get a monthly charge for the extra receivers. a phone jack Works with any phone device. Engineering breakthrough gives you unlimited This breakthrough phone extensions without wires or technology will fulfill all of your expensive installation fees single -line phone needs. It has a special digital interface for use with your fax machine or modem. You can even use it with your answering machine just by plugging it into the Wireless Phone Jack receiver. Special factory- direct offer. To introduce this new technology, we are offering a special ou don t have to have a teenager to able to move your phone to rooms or areas factory-direct pack- appreciate having extra phone jacks. that have never had jacks before. age. For a limited Almost everyone wishes they had more Clear reception at any distance. The time, the transmit- phone jacks around the house. Wireless Phone Jack uses your home's exist- ter is only $49. One When I decided to put an office in my ing electrical wiring to transmit signals. This transmitter works home, I called the phone company to find gives you sound quality that far exceeds cord- an unlimited num- out how much it would cost to add extra less phones. It even exceeds the quality of pre- ber of receivers The Wireless Phone Jack lets phone jacks. Would you believe it was $158? vious devices. In fact, the Wireless Phone Jack priced at $49 for the you add a phone, modem, No more excuses has ten times the pow- first one and $39 for fax machine or answering Today, there are a er of its predecessor. each additional re- machine almost anywhere. Is the Wireless Phone thousand reasons to Jack Your range extends ceiver. Plus, with right for you? get an extra phone jack as far as you have elec- any Wireless Phone Jack purchase, we'll throw and a thousand excus- The Wireless Phone Jack works with trical outlets: five feet in a phone card with 30 minutes of long distance (a $30 es not to get one. Now any single -line phone device. Almost or five hundred feet. If value) for only $9.95! an engineering break- anyone could use it, especially if... you have an outlet, Try it risk -free. The Wireless Phone Jack is backed by through allows you to Few jacks. You want more phone you can turn it into a Comtrad's exclusive 30-day risk - free home trial. If you're not completely satis- add a jack anywhere extensions without the hassle and ex- phone jack -no matter far fied, return it for a full "No Questions Asked" you have an electrical pense of calling the phone company. how away it is. The outlet. Without the Wireless Phone Jack's refund. It is also backed by a one -year manu- hassle. Without the ex- Bad location. You have jacks, but advanced companding facturer's limited warranty. Most orders are pense. And without not where you need them most, like noise reduction fea- processed within 72 hours and shipped UPS. the miles of wires. in the kitchen, garage, home office or tures guarantee you Wireless Phone Jack transmitter ...$49 $4 S&H outside on the deck. crystal-clear reception Like plugging in an Wireless Phone Jack receiver $49 throughout even the $4 S&H appliance. Now you Renting. You want to add exten- save $10 on each additional receiver-$39 can add extensions sions, hut you don't want to pay each largest home. with a remarkable new time you move. Privacy guarantee. 30- minute long distance phone card $SÖ device Wire- You $9.95 with Wireless Phone Jack purchase called the Other phone devices. You have can use The Wire- less Phone Jack. It Jack in an answering machine, modem or fax less Phone any allows you to convert electrical outlet in Please mention promotional code 017 -PL-6620. machine you want to move to a or your phone signal into around your For fastest service, call toll -free 24 hours day more convenient place. home, an FM signal and then even if it's on a differ- 800 -992 -2966 broadcast it over your The Wireless Phone Jack System ent circuit than the 'A1 home's existing elec- consists of a transmitter. Each Wire - = trical wiring. transmitter less Phone Jack uses To order by mail, send check or money order for the total Just plug the trans- (right) and a 4 one of 65,000 different amount including S&H (VA residents add 4.5% sales tax). Or receiver (left). charge it to your credit card by enclosing your account num- mitter into a phone One trans- security codes. You can ber and expiration date. jack and an electrical mitter will be assured that only outlet. You can then operate an your receiver will be CIIIKTRIIII insert a receiver into unlimited num- able to pick up trans- INDUSTRIES 8 ber of receivers. any outlet anywhere in missions from your 2820 Waterford Lake Drive, Suite 106 your house. You'll be transmitter. Midlothian, Virginia 23113

www.americanradiohistory.comAmericanRadioHistory.Com GIILO Prime Star Gazing

PRIMESTAR DIGITAL DIRECT BROAD- CAST SATELLITE SERVICE. Primestar Partners, Three Bala Plaza West, Suite 700, Bala Cynwyd, PA 19004; Tel. 610 -617 -5300; Price: Monthly fee varies with distributor and program options.

Astronomers tell us that the universe is expanding. We'll have to take their word for it, because it certainly isn't apparent to us, and doesn't have much effect on our day -to-day lives. We don't need astronomers, however, to tell us that the television universe is, has been, and continues to be, expanding. All we have to do is open up the latest issue of TV Guide, and then recall the way it looked during our childhood, when there were the three major commercial networks, three local stations, and PBS. Then cable TV hit the scene, offering first better reception on local stations in many areas and, later, a host of new programming choices. Most people who lived in areas where cable was offered con- AIM sidered themselves lucky to be able to see CIRCLE 58 ON_FREE INFORMATON CARD recently released motion pictures, sport- ing events, MTV, and the like. They were even happy to pay the reasonable fees that were charged to receive the improved services being offered. only folks to become disenchanted with town is so tiny that it has no doctor and no Over the years, however, the thrill wore the service offered by local cable compa- full- service grocery store. And, with only off. Prices for services (many of which we nies, but we did something about it. We 301 residents, providing cable service is no longer found enthralling) began slowly, finally got fed up and went cold turkey, not an economically feasible proposition. but very surely, to rise, and the cable corn - canceling our cable subscription, and re- People living in Arietta had rather lim- pany began using equipment and tech- verting to watching only the UHF/VHF ited viewing options. They could use their niques that tended to interact poorly with stations pulled in by our rooftop antenna. rooftop antennas to pull in (under optimal state -of-the -art TVs and VCRs. Movies Those who live in areas where decent reception conditions) two broadcast chan- came out on video long before they hit network reception is not possible without nels. Usually, those channels were cable -and it was much easier to fit a cable haven't had the option to disconnect. plagued by interference, and sometimes rented movie into the viewer's busy sched- And millions of households, mostly in they couldn't be seen at all. The only other ule than to watch a movie as it was shown rural areas, haven't even had the option to option -besides giving up on TV al- on cable. try cable to see if they like it -cable ser- together-was to buy and install a large - With virtual monopolies in their mar- vice simply isn't available in their neigh- dish satellite system. kets, many cable companies have taken borhoods. Satellite TV has been an option since advantage of their subscribers, charging One such spot is Arietta, New York, the 1970s for cable- deprived (or anti -ca- excessively high prices and offering poor located in the Adirondack State Park, ble) people. It provides hundreds of chan- service in return. We are certainly not the about 65 miles north of Albany. The rural nels, and generally better reception than 9

www.americanradiohistory.comAmericanRadioHistory.Com that offered by cable. On the downside, it requires somewhat complex, usually professional installation, a major financial outlay, and a dish -shaped antenna that measures up to 10 feet in diameter and must be mounted with a clear line of sight to the satellites orbiting above the earth. Although there is plenty of free programming on satellite, owners still have to pay an additional monthly fee for subscrip- tions to traditional cable channels. Last fall, however, Arietta entered the new age of satellite TV. The town was chosen as the site for a 60 -day free trial of Primestar, a digital DBS (direct broadcast satellite) service. The residents' viewing options jumped overnight from two to 77 channels. Primestar is one of 'two digital DBS systems making news across the country these days; the other is RCA's DSS. This The Primestar receiver should look right at home on your equipment rack. It's about month, Gizmo offers a hands -on review of the same size as a VCR. Primestar; RCA, Primestar's main competitor, chose not to participate in a head - Primestar customers, on the other hand, Primestar's antennas vary in size from 32 to- head review. Both systems are taking don't buy any equipment. Instead, they to 39 inches, depending on geographic the television world by storm. pay a one -time installation fee of about location and weather patterns. $150, and then a monthly fee that starts at DIGITAL SATELLITE SYSTEMS about a dollar a day for the rental of the PUTTING PRIMESTAR TO WORK The two systems have a lot in common. dish, the decoder, the remote control, and Our installation, on the south shore of Both Primestar and DSS use digital corn - some basic programming. A "nominal" Long Island, New York -an area that is pression to squeeze more channels from fee is added to the monthly bill for extra one of the most heavily penetrated by ca- less satellite, and both offer what they call set -top decoders. Maintenance and up- ble in the U.S.- contained one of "near laserdisc- quality" video and CD- grades are handled, and paid for, by the Primestar's new elliptical dishes. It mea- quality sound. The move to digital trans- Primestar supplier. sures approximately 39 inches across, and mission wasn't motivated to provide better The buy vs. rent debate reflects philo- 29 inches in height. For our temporary picture quality, but to increase channel ca- sophical as well as practical differences. installation, the dish was mounted at pacity. Both systems use higher -power sat- DSS advocates tout the independence that ground level on the backyard lawn, with ellites than standard satellite TV, allowing comes with owning your own gear. the mount secured by strategically placed smaller dishes to be used. (DSS broad- Primestar stresses the worry-free nature of cinder blocks. (Because we're familiar casts from the FSS or fixed satellite band. renting equipment, the lack of a high, ini- with C -band dishes mounted in concrete or Primestar broadcasts from a traditional, tial cash outlay, and the promise of free something similarly stable, we worried medium -powered Ku -band satellite.) upgrades as the technology improves. that our cats might accidentally knock the Both systems also promise to be an al- Those opposing viewpoints are not sur- dish off kilter. But the installers assured us ternative to standard cable services and to prising when you consider that DSS is the that, while they had seen a few cases of standard satellite TV. However, each ser- brainchild of a consumer-electronics com- cows rubbing against the dishes and caus- vice shares many similarities with cable pany, Thomson Consumer Electronics. ing problems in rural areas, not even our companies, and in fact, Primestar is Primestar Partners, on the other hand, is a largest domestic cat could do any owned by a consortium of cable providers. consortium made up of subsidiaries of six damage.) The biggest difference between the two major cable companies-Tele- Communi- Finding a clear line of sight to the small -dish systems is that DSS is a con- cations, Inc., Time Warner Cable, Corn - Primestar satellite, even from ground sumer product, while Primestar is a "ser- cast Cable, Continental Cablevision, level, presented no problem to the experi- vice." The potential DSS owner can go to Newhouse Broadcasting, and Cox Cable enced installer. (The installer, from his or her local electronics store and spend Communications-and G.E. American Halstead Communications in Albany, NY, between $700 and $1000 for a basic sys- Communications, Inc., which owns the actually used the installation to train a tem, and about $150 more for professional satellite used by Primestar. local crew.) Cable was run through a hole installation (although about 40% opt to The two systems also use different com- drilled in a basement- window frame, then install it themselves). Adding a second TV pression methods and satellite dishes. Al- up through a previously installed PVC to the system requires the purchase of a though both intend to upgrade to the conduit to the living room. The set -top $650 "slave" receiver. The DSS owner international MPEG -2 standard in the near decoder was connected to our TV and to a then calls one or two program suppliers to future, at present DSS uses MPEG -1, phone line, which allows the box's built -in subscribe. Maintenance and upgrades are while Primestar uses General Instrument's modem to communicate billing and pay- his or her responsibility. DigiCipher compression scheme. Perhaps per-view information. the most obvious physical difference be- The entire process was quick and Gizmo is published by Gernsback Publica- tween the two systems is dish size. Both tions, Inc., 500-B Bi- County Blvd., Farm- painless. From the front of the house, no use dishes that are much smaller than stan- ingdale, NY 11735. Senior Writers: Chris F. one would know that a satellite system had O'Brian and Teri Scaduto. Copyright 1995 dard C -band antennas, but at 18 inches in been installed. And, like the residents of by Gernsback Publications, Inc. Gizmo is a diameter, the DSS dish is somewhat small- Arietta, we suddenly had access to about 10 registered trademark. All rights reserved. er than those used by Primestar. 70 cable channels.

www.americanradiohistory.comAmericanRadioHistory.Com TAKING CONTROL The other on -screen display menus can theme: love stories, westerns, mystery, The Primestar 300D decoder box is be used to buy pay- per-view programs, and general interest). Two versions of The standard component size -much bigger view your purchase history, set program Disney Channel and two versions of TV than the typical cable box, but about the and sleep timers, and receive messages Japan (one in English, one in Japanese) same size as a VCR. A prominent display from your Primestar distributor. The pur- rounded out the premium stations. Special shows the channel number, and also fea- chasing submenu lets you know the name interest programming included C -Span, tures signal, timer, and SAT /TV indica- of the movie or event, the actors' names, The Weather Channel, CNN, Headline tors. Front -panel controls are limited to the price, the rating, the starting time, and News, TNT, Turner Classic Movies POWER; CENTER, used to confirm and acti- the amount of time remaining before it (TCM), TBS, The Discovery Channel, vate channel selections and to terminate starts. The sleep timer turns off the audio The Learning Channel, A &E, USA Net- user passwords; GO BACK, to return to the and video- although not your TV or work, the Sci -Fi Channel, The Family last- viewed channel; and CHANNEL UP and VCR -at a user -specified time. The pro- Channel; the Cartoon Network, The DOWN and VOLUME UP and DOWN arrow gram timer lets the Primestar decoder Nashville Network (TNN), and Country keys, arrayed around a MENU button that's work in conjunction with your VCR. It Music Television (CMT). Besides ESPN used to access Primestar's on -screen menu won't control your VCR, but it allows you and the Madison Square Garden Network system. When the menu is on- screen, the to set the decoder box to tune into as many (MSG), Primestar offers 14 regional sports four up and down arrow keys take on a as two daily programs and three one -time channels. In addition, it's possible to buy different role; selecting and maneuvering events up to a year in advance. The settings "season passes" to NBA basketball and through sub -menus. are saved in memory, and protected by a NHL hockey games. There are 10 All of the front -panel control keys are battery backup. You can use the program PrimeCinema pay-per -view channels, and duplicated on the remote. In addition, the timer to purchase a pay -per-view event in six PrimeAudio music channels -com- remote control offers a numeric keypad for advance for later viewing or taping. mercial -free, audio-only satellite radio. directly entering channel or password Should your distributor send you a mes- All the major broadcast networks- numbers, a BUY button for purchasing pay - sage, the word "message" will appear the ABC, CBS, NBC, Fox, and PBS-are per -view programming, a SAT /TV key for first time you press the VIEW key on the also represented, but not as we're used to switching between Primestar and local TV remote control, letting you know to check seeing them. Rather than local affiliates, inputs, and MUTE. Pressing the VIEW the message submenu. Primestar delivers NBC out of Boston, button calls up an on -screen display con- ABC from Miami, CBS from Washington sisting of the currently selected channel, TUNING IN TO PRIMESTAR DC, Fox from San Francisco, and PBS service, program name, rating (if applica- As soon as the installers left, we settled from Philadelphia. Although the program- ble), and time of day. The NEXT key pro- down, remote in hand, to see what ming lineups are virtually identical to vides the same information about the next Primestar was all about. A quick scan those on our local stations, it can be dis- program that will be shown on the current through the "dial" revealed several movie concerting to watch the evening news (par- channel. If the current channel is a pay - channels -three HBO, two Cinemax, and ticularly the weather reports) from other per-view station, the "view" or "next" four Encore (each dedicated to a different cities. Of course, the decoder's pass- display will also include prompt lines -for instance, "Press BUY to purchase program." The remote control that came with our system was one of Primestar's new, up- graded units, that also features five buttons labeled "future entertainment services." Those buttons currently serve no purpose, but they eventually will be used to access the interactive guide Primestar plans to launch next year, along with any future interactive capabilities as they become available. For now, the only interacting you'll do is with the on -screen menu system. The main menu offers eight options, any of which can be selected using the remote's numeric keypad or by scrolling through the main -menu options with the arrow keys and then pressing ENTER to access the submenu. Three of the sub - menus probably will be used only during the initial system set -up. Those include the Receiver Status Screen, used by the installers to check signal power and quality (if you call for service, your distributor might ask you to read some of the information shown on the status screen); the Set or Change Password menu; the Rating and Channel Lockouts screen, to censor your kid's viewing options; and Favorite Chan- nel Scan, for deleting channels from the Primestar's new elliptical dish can be quite unobtrusive. For our temporary installa- scan function. tion, no effort was made to hide it. 11

www.americanradiohistory.comAmericanRadioHistory.Com April 1994 marked the beginning of Primestar's national roll out. It is now available to every household in all 48 con- tiguous states. Primestar announced in March at the SBCA show that their subscriber count had surpassed the 300,000 mark -a dramatic increase from the total of 70,000 subscribers just one year earlier. Like all satellite delivery systems, the Primestar signal originates in ground stations, where it is digitized, compressed, and beamed up to a satellite, which then sends the signals back down to antennas on earth. Primestar uses several transmission locations in Colorado and New Jersey. The signal is boosted in power once it reaches the satellite. It is then channeled back via the dish antenna to the subscriber's set -top decoding box, where the signal is de- compressed before being sent on to the television set. Primestar dishes vary in size to suit the installation site, taking into account the geographic location and local weather conditions. They currently range in size Primestar digitizes its signals before they are transmitted to a geostationairy, medium - from 32 to 39 inches in diameter. power, KU -band satellite. They are then distributed across the continental U.S. That could change in the near future, however. Primestar plans to deploy two through antenna connector (sAT /Tv programming is a delight. As promised, high -powered satellites in 1996. Those button) makes it easy to watch local broad- the digital satellite system provides excel- birds, built by Loral, are said to be the casts or cable -delivered programming as lent video and audio quality. We had no most advanced satellites of their type avail- well. complaints about "rain fade," which is able. The more powerful satellites will al- Between our test period and our pub- often associated with small -dish satellite low the use of smaller dishes, and will lication date, Primestar added six new ser- reception. In face, we experienced no inter- increase Primestar's channel capacity to vices. Those include another premium ference whatsoever in our two -month trial up to 200 channels with Dolby AC3 digital movie channel, Starz!; Playboy TV pay - period. audio compatibility. per -view adult entertainment; CNN Inter- On a few occasions the picture would national news; QVC home shopping net- take on a very slight jumpiness. Perhaps WHAT DOES IT COST? work; CNBC for stock -market coverage that is an exaggeration -we couldn't pin- Because Primestar is a service, not a and business features; and The Golf Chan- point any digitization of the picture. On product, initial costs are limited to in- nel, featuring all golf, all the time. rare occasions, however, the video was less stallation fees, which vary by distributor. Completing the lineup is the PreVue than smooth. The effect never lasted lon- Generally, installation will set you back Channel on -screen program guide. It of- ger than a minute or so, however, and usu- between $150 and $200. fers a continuously scrolling program grid ally didn't detract from our viewing Next, you start paying for the service that displays what's on each channel for pleasure_ The only exception was when itself. Again, prices are determined by the the next 1' hours. Simultaneously, "corn- watching hockey -perhaps because the local distributor. Approximately $30 a ing attractions" or other advertising for white ice surface made artifacts more no- month gets you the Primestar basic pack- various movies and events are shown at the ticeable. However, during quick scene age, which includes use of the equipment top of the screen. changes, say, from a face -off circle to a and 30 or more "top" (not premium) cable The current PreVue Channel is not inter- comer, we could detect a slight, but per- channels. The 70 -odd channels that we active in any way -you can't click on a ceptible, delay. received would cost about $75 a month. If program choice for more details, or you want to hook up a second TV, a small choose to view only certain categories of HOW DOES IT WORK? additional monthly fee is charged for the programming. Nor will the channels you Primestar started out in I990. delivering extra decoder box required. blocked out using the "favorite channel 20 channels of satellite service to subscrib- There are no other fees involved. As the scan" on -screen menu be deleted from the ers located in rural areas not reached by new satellites and services are launched, guide. You have to watch the entire thing. cable. The original Primestar service de- Primestar distributors will absorb the cost Beginning in 1996, however, Primestar ex- livered analog Ku -band signals to rela- of the required equipment upgrades. They pects to offer an interactive program tively small (36-39-inch) stationary will supply subscribers with updated re- guide. dishes. mote controls, smaller dishes, and In general, we found it much easier to It wasn't until last year that Primestar MPEG -2- compatible decoder boxes at no refer to the free monthly program guide began using the General Instrument Digi- charge. that's included with any Primestar sub- Cipher digital compression system, which Of course, if programming pricing con- scription. To augment the printed guide - allowed them to squeeze 70 channels from tinues along the same lines (30 -plus chan- i.e., when we couldn't easily locate it- the same satellite, provided by GE Amer- nels for $30, 73 channels for $76), those we made frequent use of the handy VIEW icom. The April 1994 launch date did, distributors are facing a no-lose situation and NEXT keys on the remote control. however, make Primestar the first digital when Primestar begins broadcasting more 12 Watching, and listening to, Primestar satellite system on the market. than 200 channels next year.

www.americanradiohistory.comAmericanRadioHistory.Com Just plug it in. Are animals turning 1'ard Gard's trans- your yard into a zoo? former plugs into any standard household outlet. Elec- tricity consumption is very low and costs only about 25¢ a month to operate. Yard Gard is de- Do dogs like your signed for outdoor yard better than operation in all types their own? of weather. You can use your Yard Gard all year. Mount your Yard Gard on a wall, post, or fence or place it on Are rabbits eating as much from your a flat surface. Yard garden as you are? Gard is essentially maintenance -free and requires only a minimum of care. Three settings. How ultrasonic power can safely deter Yard Gard has three frequency settings. Do you have lowest fre- problems with from your yard... At its unusual animals? unwelcome animals quency setting, one away annoying Yard. Gard covers an Yard Gard creates a wall of silent noise that drives oval area of approxi- dogs, cats and many wild animals without harming them. mately 4,000 square feet the size of an average city lot. Anton by Charles Additional units can be added to especial- Do neighborhood think your gar- Be honest. Even if you're an animal Ultrasonic Power. Yard Gard's electronic cats ly large yards. den is a litter box? lover, you don't want strange animals ultrasonic generator broadcasts powerful Keep the birds. in your yard. "silent noise" that repels four-legged yard Do you love to watch and feed birds in your what I'm talking about... dogs pests, yet is generally unobtrusive to people. You know yard? If you have problems with cats chasing Tones are harmless but animals find the that dig holes and foul your lawn, cats that Yard Gard is the sounds so unpleasant birds away or killing them, trample your flowers answer. Birds are not affected by the high fre- your car. that they flee. and sleep on quency sound waves. They can't hear it, but in a rural Cruelty -free pest control Why it works. Small If you live cats can't stand it. area, you've probably that works... animals depend on their had trouble with un- acute hearing for sur- Risk -free offer. For a limited time, you can 'n the past, people relied on poisons or introductory invited visitors like vival. They can hear in get the new Yard Gard at the violent means ;oget rid of unwanted price of just $99. Call today to take advantage raccoons, possums, animal pests. Runt environmental the 18 to 25.5 kilohertz of this special factory direct pricing. All rabbits, or armadillos. awareness has increased the demand for range which is beyond Comtrad products are backed by our "No Until now, there clean, non -lethal methods of pest control. the range of most hu- Questions Asked" money -back guarantee. If weren't many options. Safe and humane. Yard Gard is the mod- mans. When critical you're not satisfied with the Yard Gard, sim- After all, you wouldn't ern solution for pest control. hearing frequencies are ply return it within 30 days for a full refund. want to harm a stray disrupted by strong Humane. Yard Card causes no harm Yard Gard is also backed by a two year man- animal, and your ani- a wall of high pulses, animals feel to animals. By creating ufacturers warranty. mal control agency frequency sound, it forces them to leave threatened and leave may take days to re- the area and creme new habitual routes. the noisy area. Yard Yard Gard $99 $12 S&H While the sound s very annoying to ani- Gard takes advantage of spond, if they ever do. Please mention promotional code 502 -PL-6621. mals, it is virtually unobtrusive to people. fact to protect your High -tech solution. this yard from pests. For fastest service call toll -free 24 hours a day Fortunately, modern Nature friendly. Poisons and pesticides technology has provid- can pollute soil aad water sources. Yard Break their habits. 800-992-2966 ed an answer: the new Gard deters Animals are creatures of Yard Gard. It uses high pests with habit. They establish a a a ® sound so it frequency sound waves territory and generally To order by mail, send check or money order for the causes no to force unwanted ani- follow the same travel total amount including S&H (VA residents add 4.5% damage to the )y+! r. credit card, endose mals to leave the area. routes. Yard Gard forces sales tax.) Or charge it to your environment. your account number and expiration date Yard Gard elimi- animals to change their nates the need for Non-toxic. Chemicals used to patterns and establish eliminate pests be dangerous to repellents, trapping or an new ones. They soon COMWD humans or neighborhood pets. Yard physical attacks. Pests modify their habitual INDUSTRIES Gard poses no health risk when used routes to avoid Yard learn to avoid the areas 13 as directed. zones. 2820 Waterford Lake Drive Suite 106 Yard Gard protects. Gard Midlothian, Virginia 23113

www.americanradiohistory.comAmericanRadioHistory.Com there was always the chance that he could have fallen or been knocked down by a wave. And it was impossible not to think of all the horror stories of kidnappings that are in the news. It was an experience that none of us-except the boy himself, of course, who wasn't aware that anything was wrong -is likely ever to forget. It's easy for anyone who doesn't have kids to think, "What kind of parents are you? Can't you keep an eye on your own kids ?" But anyone who has ever cared for a toddler knows that, once they learn how to walk, children can move as fast as lightning on those stubby little legs. We rarely told the lost -at- the -beach story without hearing similar tales from other parents, whose kids had wandered off at amusement parks, tourist attractions, malls, playgrounds, or even from their own back- yards. It's often said that parents need eyes in back of their heads, and even that might not be enough. In the time it takes to pay for an admission ticket or a Happy Meal, tie another child's sneaker, or greet a friend, a small child can disappear. Some parents rely on leashes and har- nesses to keep their kids from straying away in crowded public places. Such rigs are likely to draw disapproving stares from strangers who believe leashes are proper only for pets. But if your child tends to wander, we believe it's better to keep him or her safe than to pacify strangers. A less obtrusive, and more high -tech means of keeping track of your child is the BeeperKid child- monitoring system from A + H International Products. The wireless, digital system consists of a transmitter, worn by the child, that automatically sets off an alarm on the parent's receiver unit when it moves beyond a 15 -foot range. Beeper A series of beeps warns the parent that his Babysitter As soon as we'd settled in, the rest of us or her child is wandering. went down to the shoreline to help super- The parent's unit is oval- shaped and BEEPERKID CHILD MONITORING vise the kids who were swimming. We measures approximately 21/2 x 2 x 3/4 SYSTEM. From A+ H International automatically did the routine head count - inches. A clip built into the back of the Products, Shoreline Square Tower, 301 -and suddenly realized there were only receiver allows it to be attached to a belt or East Ocean Boulevard, Suite 1010, Long seven kids with us. The three -year-old had pocket. At the top of the unit is a yellow Beach, CA 90802; Tel. 800 -455 -4345. wandered off. MUTE button. A green LED on the front Price: $149.95. In a state of barely controlled panic, we blinks slowly to show that the unit is began to search for him. We knew he was charged and working. When the child is When friends who'd moved to the Mid- too afraid of the water to have gone in out of range, the LED flashes, even if the west returned to Long Island with their without being carried, so we concentrated unit has been muted. The speaker is also kids for a visit last summer, the old gang on the three other directions he could have found on the front of the unit. immediately planned an outing to the headed. We split up, with one person look- The transmitter is even smaller and beach. The group included four adults and ing either way along the shoreline, and a plainer. The circular unit measures just eight kids, aged 11, 9, 6, 5, 4, 3, and 2 third heading back toward the parking lot. over two inches in diameter and 3/4 -inch years, and 6 months. Less than 10 minutes later, a woman, wide. It also features a speaker and an As soon as we hit the sand, all of the holding the little boy by the hand, found LED on the front. Instead of a clip, how- kids who were old enough to walk stripped us. Having seen him wandering westward, ever, the transmitter has a "safety pin" down to their bathing suits and raced for she turned him around and led him back to built into its back panel, and there is no the ocean before we'd managed to spread where she'd assumed (correctly) that he'd MUTE button. That design makes it diffi- out a single blanket. One of the adults come from. cult for the child to remove or tamper with went to the water's edge to keep an eye on Those few minutes seemed like hours. the monitoring system. the kids, while the rest of us set up Although we were all pretty sure that he The BeeperKid also comes with a 14 "camp." wouldn't have gone in the water by choice, charging stand and an AC adapter cord.

www.americanradiohistory.comAmericanRadioHistory.Com The two units slide together, back-to -back, tary technology eliminates the reliability BeeperKid's proximity- detection tech- virtually all and then snap into the stand. An overnight' problems inherent in RF technology, and nology is extremely reliable in no clear charge provides up to six hours of monitor- complies with FCC regulations. environments, even when there is and the ing. When the two units are disconnected, In addition, each BeeperKid system has line of sight between the parent claims the system powers up automatically and its own code. That allows it to recognize its child. Our tests verified A +H's and receiver worked emits a confirming beep. Sliding the trans- companion transmitter/receiver even if that the transmitter the child mitter and receiver together again shuts other BeeperKid systems are being used in through walls, such as when up a flight of down the system. the area. moved into another room, or even into an Once charged, the BeeperKid is simple Despite the "secret" proprietary tech- stairs, out the front door, course, it also worked when to use. You simply clip on your receiver nology, the BeeperKid is affected by the elevator. Of off a backyard deck and your child's transmitter, and forget presence of a strong interference source - the toddler moved or the driveway, and out of about it -until you hear a series of beeps, such as a computer or a television- within toward the pool swing area of the that is. Then it's time to locate your little a few feet of the parent's receiver unit. the sandbox toward the was in danger of wanderer, knowing that he or she can't When there is strong enough interference playground, where he swings. have more than a half-second's lead, being present to affect communication between being hit by moving The 15 range was determined by approximately 15 feet away when the first the transmitter and the receiver, the receiv- -foot to be natural beep sounded. Should the child roam back ing unit will beep to alert the parent to the the manufacturer's tests "the their kids... into range, or be found, the beeping will situation. The manual advises parents to limit most parents place on that range, cease, and the unit automatically resets. become familiar with the effects of inter- when their child moves beyond and pay more at- The mute button will silence the alarm, but ference on the system before leaving they immediately notice with that opin- the LED will keep flashing as long as the home -by experimenting with the tention." We tend to differ range would vary child is out of range. BeeperKid near a TV or computer -so ion; in real life, the In the back- Although the idea behind BeeperKid is that they will realize when it is detected in according to the situation. there are few simple, its execution was anything but. a public place-at a check -out counter, for yard, for instance, where the has a fairly According to A + H, the original concept instance. The more interference being hazards and parent clear be given much relied on radio -frequency technology, but emitted, the shorter the effective range be- line of sight, a child could would, for instance, that design had several flaws. At the top of comes. greater leeway than he park. In the list was reliability. Two units moving The range also shortens when the bat- in a crowded mall or amusement quickly continuously, particularly in an urban en- tery power is running low. The unit will either of those places, he could a legs, a ticket vironment, were subject to signal -strength also begin to beep, even though the child disappear behind strangers merchandise variations -and dropouts-caused by re- remains in range, letting you know that book, a rack of clothing, or a than a cou- flection and blockages. Reflected signals recharging is needed. counter-without getting more parents. could cross and cancel each other out, With those two exceptions, the ple of feet away from his making the parent think incorrectly that the child was still within range. And the rate of false alarms was too high. The performance of RF -based products technology is also highly dependent upon antenna orientation. At one point during the design process, it was suggested that the parent wear an antenna on his or her head to provide an unobstructed view of the child's transmitter. Somehow, we can't see adults rushing out to buy a product that required them to walk around with an antenna sticking out of their heads! FCC regulations caused further problems with the original RF design. The FCC requires at least a ten -second delay between the time the child leaves the range and the time of transmission. To help eliminate false alarms, that delay is multiplied two or three times. That means that there could be a delay of up to 50 seconds in some situations. A + H finally abandoned the early, RF model. Instead, it licensed from a Fortune 150 defense contractor a proximity- detec- tion technology that had been developed for military applications by aerospace and defense engineers. The company is close- mouthed about the proprietary technology. except to say that it is "essentially a wireless modem, modulating and demodulat- ing digital data across a wireless medium," and that custom. Application The BeeperKid receiver (front) and transmitter (rear) slide together for easy storage Specific Integrated Circuits (ASICs) are and recharging when not in use. Note the "safety pin" fastener on the back of the 15 used in its manufacture. The adapted mili- receiver, which prevents toddlers from removing the transmitter.

www.americanradiohistory.comAmericanRadioHistory.Com ple who read them. If an engineer who Entering the regularly works on A/D- converter design reads your post and can contribute to solving your problem, he will. Internet The minimum computer requirements for running WinNET Plus are an 80386 - WinNET PLUS INTERNET ACCESS based system with two megabytes of RAM SOFTWARE. Published by: WinNET and a modem. The software is supplied on Communications, 330F Distillery Com- a single floppy diskette and is very easy to mons, Louisville, KY 40206-1919; Tel. set up: From the Windows Program Man- 502- 589 -6800. Price: $39.95; Subscrip- ager, just run SETUP.EXE. tion also required. The setup program copies all necessary program components to the directory of Are you on the Internet? The worldwide your choice, and sets up the subdirectories network-the much -heralded information that are necessary for the program's proper superhighway-is experiencing a fantastic operation. It then asks several questions so population explosion with good reason: that it can configure the system properly. it's not only incredibly useful, but it can be For example, it asks for your local time a lot of fun, too. zone. Most people on the Internet don't pay It also asks whether you wish to use CIRCLE AO for the access -it's provided by their com- ON FREE INFORMATION CARD WinNET Communications as your Inter- panies or schools. But a growing number net/Usenet provider-an alternative proof individuals are recognizing the impor- Internet to exchange e-mail and to com- vider can be chosen instead. If you do tance of the Internet and are setting up municate on Usenet newsgroups. People select WinNET as your Internet/Usenet private accounts to obtain access. One who access the Web frequently are happy provider (as we did), you must choose a popular way to get Internet access is with the information it provides -but they system name and a User Name that will be through the "big five " -America Online, still see much of it as a novelty. New Inter- used to create your Internet mailing ad- CompuServe, Prodigy, Delphi, or GEnie. net users find that e-mail and Usenet move dress. Your Internet address then takes the But there are plenty of smaller companies beyond the novelty stage and become inform: that can provide access as well. dispensable resources almost imme- user-name @system . win. net One of those is WinNET Communica- diately. -name tions, which has bundled an access pro- The WinNET software is designed to The program then asks you to provide gram, WinNET Plus, together with its work "hand and glove" with WinNET the information necessary for WinNET online service to give consumers an easy Communications' Internet/Usenet ser- Mail to talk with your modem-port, way to access the two most popular service. However, the software can work with speed, and setup string. You can also set vices available on the Internet. other providers as well, as long as they the CPU utilization in four steps from low There are many different ways to access support UUCP, the Unix -to -Unix Copy to very high. Setting it high can improve the Internet, and before you can choose an Protocol. the communications performance some- Internet- access provider, you have to deter- The primary use of e-mail is to send what. However, it makes it difficult to run mine what kind of access you need. Some messages to other members of the online other programs concurrently. So, for ex- dedicated access providers will supply you community. But there are ways to access ample, if you wanted to run other applica- with a Unix shell account. Others will set other Internet services via e-mail as well, tions while the mail program downloaded up what is known as a SLIP or PPP ac- which we'll describe shortly. your e-mail and news, you would set the count that lets your computer actually be- Usenet can be thought of as a global CPU utilization to a low or middle setting. come part of the Internet. WinNET Plus, bulletin board -the world's largest BBS. The setup software creates a new Pro- and the corresponding service from Win - It is divided into thousands of categories gram Group for WinNET programs. The NET Communications, offers Internet e- or newsgroups (now about 7000 and grow- five programs are: WinNET Plus, Call mail and Usenet newsgroups with the ing all the time). Anyone is free to read and Server, Scheduler, WinNET Setup, and friendly face of Microsoft Windows - post bulletins in categories that range from Account Setup. there's no need to even think about Unix. computer security to gardening, and that WinNET Plus (WNMAIL.EXE) is the The main benefit of WinNET Plus is cover virtually every subject in between. main program that is run daily to send and that it is very efficient. The software is Newsgroups are an incredibly vast source receive mail. Call Server (UUCICO.EXE) used primarily offline, so that users can of information because everyone can con- is the communications program that you compose mail and read mail and news "off tribute-and people on Usenet talk about can run directly when you want to send or the clock" without being charged for con- everything imaginable. receive your mail immediately. nect time. If you have a question, for example, Scheduler (DAEMON.EXE) is a back- By the time you read this, WinNET about who played drums on John Col - ground program that schedules communi- Communications will be able to provide trane's classic LP "Giant Steps," you cations calls for any time of the day or other services beyond mail and news, in- might post your query in the newsgroup night. You might set it to call your provider cluding SLIP /PPP connections that put rec.music.jazz. If you are wondering in the morning before you get to work so your computer directly on the Internet, about the security of the encryption in that when you arrive at your desk, you'll and that provide access to the World Wide PKZIP file- compression software, you have your mail and news waiting for you. Web. That access wasn't available during might ask for comments in the sci.crypt The Account Setup (ACCOUNT.EXE) our review. newsgroup If you have a problem trying to program is run to establish your WinNET Although the World Wide Web is get- choose the right analog -to- digital convert- Internet account. WinNET Setup (SET ting the most attention these days, e-mail er for a speech -recognition system that you UP.EXE) also provides an icon so that you and Usenet are by far the most popular are desiguing, you might post questions in can re-run it and adjust communications Internet services -each day, about 25 mil - sci .electronics . settings if it ever becomes necessary. 16 lion people around the world access the The real value of newsgroups is the peo- The rate for on -line usage of the Win-

www.americanradiohistory.comAmericanRadioHistory.Com and vandals. And they can keep you from tripping over unexpected objects in the path -like toys or ice and snow. Factory- direct offer. This advanced solar lighting technology would retail for hundreds Lin stores. But through this special factory -direct offer, you can get the Solar Pathway Light for just $59. Order extras, and receive them for just $49. The Solar Sensor Light is available for only $79 with additional lights costing only $69 each. Take advantage of this special offer to add beauty and safety to your home and yard.

Solar Sensor Light for extra security. Equipped with the same powerful technology as the Solar Pathway Light, the Solar Sensor Light offers you and your family extra protection for your home and outbuildings. This powerful f lood- light uses solar power to light your yard with a powerful gtrtrtz- halogen bulb. And it has a built - With convenient wireless installation, in heat and motion sensor. With no timers or switches to ;et, this light automatically switches on when triggered and stays on after you leave two lighting systems offer the brightest for 30 to 60 recconds. The adjustable 30 to 60 second delay ensures that you'll never be left in the solar light ever available! dark. With ro wiring, of it's easy to in- Alpan's industrially -proven solar technology harvests the power stall. The solar the sun to protect your home and family. panel mounts directly on yosr roof. by Bob S. Garrard The light mounts How many nights have you had to Industrial technology. Alpan has put the anywhere. The 14- negotiate a dark walkway to the single crystal cell, the same powerful cell foot plug-in cord simply door hoping you wouldn't trip on found in industrial power modules, to work connects the two. The solar something? Or how often have you stood in for you in the Solar Pathway Light. Using storage system is so powerful Economical the dark fumbling with keys? If you're like the energy collected by the cell during the it will switch on as many as and depend- me, you leave the porch light on all day, but day, the power source is charged. At night, 120 times with just a single able, the Solar Sensor Light you still have to fmd the porch in the dark! the built -in photo sensor detects darkness to full charge. And it's able has a built -in Now there's a better way to come home and automatically turns the light onto pro- run for up to two weeks - heat and mo- to the warmth and safety of a well-lit home. vide up to six hours of illumination. even if there's no sun. tion sensor. Alpan, in colabora- No bills, no wires. The solar system tion with Siemens, brightest lighting The Solar Pathway Try them both risk -free. Both systems has developed two Circuitry s.saled in Light can be in- are backed by a "No Questions Asked" 30- new lighting sys- weather-pwtectec casing Silicone staLed in minutes. day risk-free home trial and a one -year tems -the Solar encapsulated Simply twist the manufacturer's limited waranty. If you're not solar cell Pathway Light and two parts together satisfied, return them within 30 days fora full Solar Sensor Light. and put the light in "No Questions Asked" refund. Most orders High - The fluorescent the ground. All of 72 UPS. capacity are processed in hours and shipped advantage. Built batteries the connections are Solar Pathway Lgght° $59 $6 S&H with a fluorescent provide internal, so there Additional Solar Pathway Lights save $10 each bulb, the new So- up to six are no wires. And Solar Sensor Light' $79 $8 S&H hours of lar Pathway Light because these lights Additional Solar Sensor Lights save $10 each illumination promotional code 851 -PL -6622. provides the maxi- store and use ener- Please mention For fastest service call toll -free 24 hours a day mum amount of Energy- efficient gy from the sun, fluorescent for illumination while bulb bums up you'll never pay 800-992-2966 using a minimum to 100 times outdoor lighting. = ® ® amount of energy. brighter than Ensured safety. non -fluorescent To order by mail, send check or money order for In fact, the unique solar light bulbs Outdoor lighting is the total amount including S &H (VA residents add fluorescent tube is 4.5% sales tax.) Or charge it to your credit card by not just convenient. enclosing your account number and exp. date. up to 100 times Height-adjustable It makes your home mounting stakes brighter than non- safer. Well-lit walk- AY7'fltAn fasten together with 17 fluorescent solar - no hardware to rust ways and yards dis- INDUSTRIES 2820 Waterford Lake Drive, Suite 106 powered lights. courage burglars Midlothian, Virginia 23113

www.americanradiohistory.comAmericanRadioHistory.Com WinNET Plus Programs munications, less than 4 percent of its cur- QQN rent customers use more than four hours of connect time. Current customers will be able to opt to keep their current pricing D structure when the new pricing is introduced. WinNE T Plus Call Server Scheduler Queue Editor As mentioned previously, WinNET can communicate with alternate service providers. To do so, you need to give the software information about the provider. First, of course, is the provider's telephone number and such connection information CwI as the maximum connect speed. Also, you News WinNET must provide your assigned machine name Account or system name, your password, and your Cleanup Setup Setup provider's server's UUCICO machine name. You must also provide the login sequence for your provider's server. (Many providers can provide a sample login script WinNET Plus includes seven applications, including an automatic scheduler that lets you access the Internet even when you're nowhere near your computer! that shows what prompts and responses are required). Next, you must provide the e- File edit search Folders Mail News Window preferences mail address of the news administrator so that you can subscribe Q1 ?1 to newsgroups.

PIw tóox foment Dos The setup program generates a file a Incoming Mail called CHAT.RC that contains a simple S a Usenet News Group Folders script that the communications program L ° sci. electronics uses to negotiate the login sequence after it J 4 5 Ln Frn. Dale S connects to your UUCP provider. That N 'q Search 4 ° Results: sci.electronics:'Popular Electronics" chat.rc file will N 55 work unmodified for many N 46 S Ln Frame Dale S systems, but in other cases additional con- N 40 IIIN N 15 Aril, I. by Mart ;en., : IA .__._ figuration of the file might be required. .. - _ _.- .,. -'------. N 28 0 45 ham Mack Zssiw N J1 0 25 "Contact the author for software.', a common trend In Although e-mail is primarily for send- N 16 this publication's 'projects'. N 25 ing and receiving personal messages to N 6 3. PEEL18CV8 (EEPROM), from International CMOS Technology. Gould AMI N 1 other members of the on -line community, N 3 -Create Your Own IC's'. Boll Green you can do a lot more with it. For N 31 Popular Electronics. January 1990 example, N 82 A single board 280 based irhgrdescr for the PEEL18dV8 using you can send a message to a list of users, N 19 keyboard entry. No algorithm description. dLp and EPROM N 39 for z80 program' to duplicate. (Listed price vas N 52 needed send text files or binary files, and sub- cheap. about 880 in 1990.) Later versions were produced that N 25 had an interface to download from a cceputsr, rather than scribe to mailing lists. The number and N J2 keypad only entry. - N 45 scope of available mailing lists is tremen- N 7 t. CPLDe from Intel'Altera and Lattice dous, and include everything from discus- Databooks Eros Lattice, 'pLSI and ispISI Data Book and Handbook' and Intel. 'Programmable Logic' have the interface and download sions of the TV show Beverly Hills 90210 ...... specifications. (The catch here is that the data to be downloaded needs to be generated from a manufacturer provided software as to calculus. the internal layout and mapping of the device are still proprietary.) But e-mail can also be used to access This software is cheap or free. but wou need to contact the other Internet services, too. For example,

'¡fire 125W (lt-"°' 338éñ although WinNET Communications doesn't offer direct FTP (file transfer pro- A search for "Popular Electronics" allowed us to quickly find how members of the tocol) Internet community were using the magazine. capability, we were able to use e- mail to retrieve files from FTP archives. Archie, Gopher, and other Internet ser- NET system is $8.00 per hour, and the number-it isn't toll -free, however. In- vices are also available via e-mail. monthly minimum charge is $9.95. That stead, it is billed at a rate of 18 cents per Archie is an Internet utility that lets you means that if you use less than $9.95 minute during peak times (8 AM to 5 PM search indexes to locate files that are avail- worth of connect time, you will be billed Eastern Time) and 12 cents per minute of able on public servers. By e- mailing in- the minimum of $9.95. off-peak access. structions to an Archie site, you can Unlike many on -line services and bul- The 800 -number service is optional. If instruct the program to search through an letin boards, you are only connected to you are local to the company, or if you have index of files and e-mail a list of the match- WinNET for just long enough to send or a long -distance company with lower rates. ing files and the sites where they are lo- receive any pending e-mail at speeds as you are free to access WinNET at its stan- cated. fast as your modem will go. That results in dard number. Archie knows only four commands: connection times of typically one to just a A new price structure is due to go into help, prog, list, and whatis. Those com- few minutes. According to the company, effect when WinNET Communications in- mands can be set to the Archie server in an its customers average 1.75 hours of con- troduces its new SLIP /PPP services. As of e -mail message to locate files. The re- nect time per month, which results in a this writing, the service is expected to cost sponse that would be sent by e-mail would charge of $14.00. a flat $19.95 per month, for four hours of be the same as if you typed the commands In addition to connect -time charges, access though a toll -free number. After the at a terminal connected to the Internet. you are responsible for phone -line first four hours, each additional hour will Gopher is an Internet tool that allows 18 charges. WinNET does have an 800 cost $5.40. According to WinNET Com- (Continued on page 20)

www.americanradiohistory.comAmericanRadioHistory.Com Home Alone

PERSONAL EMERGENCY PHONE DI- ALER (CAT. NO. 61- 2659). From Radio Shack, 700 One Tandy Center, Fort Worth, TX 76102. Price: $99.99.

Over the last half century or so, several demographic trends have led to an un- precedented number of senior citizens living alone. First, of course, we, as a society, are simply getting older. Ad- vances in medicine and health care have resulted in longer life expectancies. While it used to be common for grown children to settle in the same areas in which they grew up, today's society is always on the move. Many young families pack up and move clear across the country, in search of better job opportunities, or simply "greener pas- tures." It is no longer common for grand- parents to live in the same neighborhood, let alone in the same house, as the younger generations and their families. It used to be the norm for several generations to live under one roof. These days, however, such a situation is often threaten- ing to all parties concerned. In part, that's because older people no longer hold the same respected position that they once independence. The biggest potential prob- well as the necklace loop, so that it could did, when their experience and opinions lem in such a situation is the threat of be attached to a shirt pocket or belt-an were valued. In our fast -paced, quick - sudden illness, injury, or other emergency. arrangement that most men would prefer. changing, technologically oriented so- If an elderly woman living alone was to The pendant is water resistant, so it can be ciety, senior citizens can have a difficult suffer a heart attack, or slip in the bathtub, worn in the tub or shower, the sites of many time keeping up with, and fitting into, the how could she summon help? household accidents. lifestyles of their children and grand- Radio Shack provides one solution: the The console measures approximately children. And it can be equally difficult for Personal Emergency Phone Dialer. It 7 x 5 x 11/2 inches. Its front panel features their busy, stressed -out children and makes phone calls for you if you can't get a numeric keypad; two piezoelectric buzz- grandchildren to find the time or patience to the phone in the event of an emergency. ers; a microphone; a RECORD button; an to appreciate their older family members The system consists of a pendant in- INSTALL/RUN Switch; and AC power, low At the same time, over the last few de- tended to be worn around the neck, and an battery, and record indicators. A 9 -volt cades, the number of women in the work easy-to- install phone -dialer console. The battery provides memory backup in case of force has dramatically increased. Many of dialer plugs into an AC outlet and is con- power failure. A telescopic antenna on the those women have also postponed having nected to the phone line. The user then back of the console picks up the RF signals children until they were established in records a message ( "This is Ann Jones. sent by the pendant. their careers. As a result, many women- I'm at home at 222 Main Street and I'm in To begin programming the console, you traditionally, the primary caregivers for trouble. Please help. "), and enters up to must switch it to its install setting, and young and old alike -now find themselves four phone numbers to be dialed in case of then press the CAu., button on the pendant, sandwiched between the demands of emergency. which lets the console recognize the trans- young children and elderly parents, while Pressing the call button on the pendant mitter. Next, you program in the phone trying to hold down a full -time job and sends a signal that sounds an alarm and numbers in the order you'd like them to be also care for the home. activates the phone -dialer console. The dialed, using the numeric keypad. As the nuclear family continues to re- console then automatically dials the pre- Keep in mind that the Emergency Phone place the extended family, and the Ameri- programmed phone numbers of family Dialer will not "wait for the tone" before can population continues to age, the members, neighbors, or friends, and plays leaving a message on an answering ma- number of senior citizens living alone is the prerecorded emergency message. A chine, or "press 1" if it has a touch -tone on the rise. For many older Americans, built -in microphone on the console allows phone. Make sure the numbers you input such independence is welcome. They the family member to listen to what is are likely to be answered by a real person, would much prefer to stay in their own happening in the older person's home. not an answering machine or voice -mail homes, near the friends they've enjoyed The pendant is a heart- shaped, off- system! for decades, and keeping to their own es- white unit that's about two inches in length Next, you can record your message. tablished routines, than uproot their lives and slightly more than 1/2-inch thick. At When you press and release the RECORD to move in with one of the "kids." the top of the heart is a loop through which button, the record indicator will light to let As long as the older person is in good a chain can be attached. The front of the you know to begin speaking. Unless health, capable of taking care of her own pendant features two buttons labeled CALL you're leaving messages with four of your daily needs, and not lonely living alone, Mid STOP. We would have liked to see a children -all of whom know who "Mom" there's no reason for her to relinquish her clip placed on the back of the device as is and precisely where she lives -it's a 19

www.americanradiohistory.comAmericanRadioHistory.Com good idea to include in the message your full name and address. With the set -up complete, the front -panel switch can be moved to the RUN position. GIZMO NEWS Should an emergency occur, a press of the pendant causes a piercing piezoelectric alarm to sound, and activates the console New Little Dishes with Dolby S -type noise reduction were phone dialer. It isn't necessary for the per- DirecTv Inc. has selected three addi- preferred by consumers. That held true son wearing the pendant to be in the same tional companies to manufacture DSS even when compared to the sound of com- room as the console for the signal to be satellite receivers: Toshiba America Con- pact discs. picked up. sumer Products Inc., Uniden America Attendees of the Winter Consumer The console is also compatible with the Corp., and Hughes Network Systems. The Electronics were asked to listen to audio X -10 control standard, so it can be used to three join Thomson Consumer Electronics demonstrations in different simulated en- control lights and appliances in the home. and Sony Corp. vironments. One survey was conducted in Using your home's wiring to send and Thomson, of course, rolled out the first a home -listening situation, where the receive signals to and from other, optional receivers in June of 1994, and began its sound of mass -produced Dolby S -type Radio Shack Plug `n Power modules, the national rollout in October. Thomson had prerecorded tape was compared to a com- system can flash indoor and outdoor lights the exclusive right to manufacture re- pact disc. The tape was recorded on Type 1 and sound a remote siren to help emergen- ceivers for 18 months or until the first mil- (ferric- oxide) tape at 80 times normal cy personnel find your house or to attract lion receivers were sold- whichever came speed. Eighty-five percent of the respon- your neighbors' attention. first. The million came first, however, as dents claimed to have heard little or no The system might not be foolproof, but DSS became the most successful new difference or actually preferred the Dolby it will surely bring some peace of mind to product introduction in consumer elec- S -type sound. the person well living alone, as as that tronics history. In "beach" and "car" environments, person's loved ones. Sony, as of this writing, was gearing up listeners compared Dolby B with Dolby S. to become the second supplier of DSS Dolby S noise -reduction clearly won with equipment, and was due to have product 88 and 90 percent, respectively, of the WINNET on the shelves by as early as May. The listeners in each environment preferring it. (Continued from page 18) three new suppliers are expected to release The study was conducted by Dolby Lab- product to the market in 1996. Hughes oratories. It was not a double -blind com- you to browse for resources using menus. Network Systems will be first, early in the parison- listeners were informed about When you find something you like, you year. Toshiba and Uniden will follow in what they were listening to. can access it without having to worry mid -1996. about domain names, IP addresses, or Cable Interface other such details. Gopher Mail is a tool Copy Protection The Electronic Industries Association's that allows you to use the Gopher search Macrovision Corporation's digital copy - Consumer Electronics Group has submit- system to find items of interest. It allows protection scheme will likely become the ted a new proposal for an interface between you to see and use a site's Gopher menus de facto standard for the digital set -top television sets, VCRs, and set -top cable through e-mail. Just send a message to a decoder industry and for pay -per -view net- boxes. Gopher Mail server, and you'll receive its works. The company recently signed a li- The FCC-in an attempt to solve con- menu in an e -mail message. You then reply cense agreement with Hyundai Elec- sumer complaints about the incom- to the message, marking the menu item or tronics, the fourteenth manufacturer of patibility of cable systems with such items that interest you with an "X ". The digital set-top decoders to be licensed. consumer-electronics features as picture - Gopher site then sends you the results by The copy -protection technology is in- picture, on -screen tuning systems, and e -mail. It's not point- and -click access -it based on a digital -to -analog converter that video recording of one program while is a little cumbersome, and you have to processes incoming digital video and con- viewing another -required the cable and become familiar with command -line op- verts it to an NTSC or PAL analog output. consumer-electronics industries to adopt a tions -but it does work! The output signal carries the copy-protec- suitable interface. If they are unable to Although UUCP service does have its tion process that allows the video to be come to an agreement, the FCC will im- limitations, we have no hesitation recom- displayed normally on a TV screen, while pose an interface standard on them. Up to mending WinNET Plus because of the at the same time preventing acceptable re- now, the two industries have been unable ease -of-use and efficiency it brings to cording on VCRs. to reach agreement. Usenet. Once you download the day's According to Macrovision, its copy - According to the EIA, the cable and news, you are free to take as long as you protection scheme will allow pay-per -view electronics industries had agreed on all want to read it and to compose replies. system operators to "offer the most cur- elements of a decoder interface that would s Better yet, unlike the "big guys" (read: rent hit movies and events to subscribers make cable boxes obsolete. However, the 2 America Online and CompuServe), you and to maximize current and future reve- cable industry insisted that an infrared by can be very selective in what you want to nues for those programs." pass be included. That would have allowed w see thanks to the program's built -in search Macrovision- enabled integrated circuits cable systems to circumvent the interface La capabilities. are available from nine authorized semi- and interfere with TV set and VCR func- Let's say you are interested in elec- conductor manufacturers: Analog De- tions. o tronics, but only as it pertains to digital vices, Brooktree, GEC Plessey, Philips, The EIA's new proposal calls for a de- rn signal processing. Rather than reading Raytheon, Samsung, SGS Thomson, scrambling -only interface. Besides mak- rn through all of the sci.electronics news- Sony, and Texas Instruments. ing it possible for consumers to use all of group, you could tell WinNET Plus to the features built in to their consumer -elec- search through all entries for "DSP" or Cassettes Live tronics equipment, the decoder interface "digital signal processing," and increase A market -research study conducted ear- should make set-top boxes open to compe- 20 the efficiency of your Usenet access. ly this year revealed that cassettes encoded tition.

www.americanradiohistory.comAmericanRadioHistory.Com ELECTRONICS WISH LIST

A Remote Possibility A new line of universal remote controls from Sole Control (46 -23 Crane Street, Long Island City, NY 11101) promises to "forever change the shape of remote controls." The remotes are designed with a vertical, standard format that should make them easier to find on a cluttered coffee table. They are also designed to be easier to use. The keys, for example, are color coded and grouped by function. The remotes offer the ability to control DSS and other satellite receivers, and they are designed to access the menu systems that are now common to feature-laden TVs. As an added bonus, the remotes can provide a sleep timer even to components that don't have one. Just leave the remote aimed at the component, and set it to shut down after a predetermined interval from one to 90 minutes. Price: from $14.95 to $29.95. CIRCLE 62 ON FREE INFORMATION CARD

Superhighway Telephone The multi- service PhonePlus telephone from US Order (13873 Park Center Road, Suite 480, Herndon, VA 22071) lets users pay their bills, shop from catalogs, and conduct ATM transactions from their homes. PhonePlus is a Sole Con :rol Universal Remotes speaker phone built around a Motorola 68000 CPU and 256 kilobytes of memory. It has a normally- hidden full alphanumeric keyboard, a 4 -line x 20- character display, and a credit -card and ATM -card reader. It can store up to 250 names, addresses, and phone numbers. The phone is designed to be used with BankPlus and ShopPlus, which are available by subscription for a monthly fee of about $15. Future services include EmailPlus and InfoPlus, which allow users to send e-mail through the Internet and to retrieve such information as sports scores, weather reports, stock quotes, and news. Price: $200. CIRCLE 63 ON FREE INFORMATION CARD

Automotive Sound. US Order ahonePlus Telephone The 7004A from Autotek (855 Cowan Road, Burlingame, CA 94011) is a four- band graphic equalizer that contains a two -way crossover and dual inputs. Each crossover switch has separate low- and high -pass crossover points and the dual inputs can accommodate dual-source units such as CD and cassette decks. The half-DIN sized chassis can be dash or console mounted. A front/rear fader is included, as are separate input sensitivity controls. Price: $199. CIRCLE 64 ON FREE INFORMATION CARD

Bedside Phone Its a close race between our desktop and night table -each is equally crowded. In an attempt to help out, AT &T (5 Wood Hollow Road, Parsippany, NJ 07054) has combined a clock radio and telephone in one package: the Clock Radio Telephone 340. The unit features such conveniences as a dual alarm (so that couples can wake up at different times), a sleep timer, a mute button, last- number memory, a lighted dial, and a 12- number memory. The AM /FM radio automatically lowers its volume when a phone call is answered. If that won't solve your clutter problem, you might choose to mount the unit on the wall. Price: $69.99 CIRCLE 65 ON FREE INFORMATION CARD AT &T Clutter- Reducing Phone 21

www.americanradiohistory.comAmericanRadioHistory.Com ELECTRONICS WISH LIST

More than a Videogame The Jaguar interactive multimedia home entertainment system from the ori- ginator of home videogame systems, Atari Corporation (1196 Borregas Ave., Sunnyvale, CA 94089) features 64 -bit architecture that makes it "more than twice as fast as 32-bit platforms," according to the company. The system is designed for high -speed animation, textured 3 -D graphics, and CD- quality sound. The system contains five processors: a proprietary graphics processing unit, a digital signal processor, an object processor, a "blitter graphics accelerator," and a Motorola 68000 16 -bit microprocessor that handles secondary processing functions. The machine is suppliéd with Cybermorph, a flying /action videogame. Other games are available at prices between $50 and $70. Price: $249.95. CIRCLE 66 ON FREE INFORMATION CARD

Atari's Jaguar Videogarne Syltern

Home - Theater Speakers Nothing brings video to life like great sound. Cerwin -Vega (555 E. Easy Street, Simi Valley, CA 93065) had that in mind when designing the Sensurround Home Theater Powered System 8. The system, which is designed for both home -theater and music applications, features three matched front speakers, a 150-watt, 12 -inch powered subwoofer with remote volume control, and two rear-channel satellite speakers. The front speakers are magnetically shielded so that they can be placed directly above or beside a TV monitor. Each has dual 51/4-inch high- excursion midrange drivers and a 1 -inch dome tweeter. They are rated to handle 80 watts. The rear-channel satellite speakers feature a single 5 -inch midrange and a I -inch dome tweeter, and are rated to handle 60 watts. A variable crossover control located on the rear panel of the subwoofer permits the crossover point to be adjusted from 45 to 150 Hz. Price: $1935. CIRCLE 67 ON FREE INFORMATION CARD Cerwin -Vega Sensurrouni Speaker System

On the Road Again Those traffic jams will become a lot more bearable with Kenwood's (P.O. Box 22745, Long Beach, CA 90801) KDC -PS900 car CD receiver. The head unit features the ability to control CD and MiniDisc changers, such as the KMD -C80 also offered by the company. Built with "autosound competition-level quality," the unit offers a signal -to -noise level of 96 dB and a dynamic range of 98 dB. The unit's total harmonic distortion (THD) is rated at 0.004 percent. Three RCA Kenwood Car Stereo preamp outputs are available, and can be switched for either two- or four-volt operation. A digital output is also offered. Kenwood's proprietary digital control system, called K -Bus, allows for system expansion. Price: $600. CIRCLE 68 ON FREE INFORMATION CARD

Shedding Some Light Nothing is worse than breaking down on the highway- unless it's breaking down on the highway at night. Eveready has two products that are designed for just such an occurrence: the Dashboard Plug -in Trouble Lantern and the Dashboard Plug -in Emergency Lantern. The Trouble Lantern is equipped with a swivel hook that rotates 360 degrees and allows hands -free illumination. That rugged ABS plastic lantern comes with a 16-foot cord that is designed to plug into a cigarette lighter to run off a car battery, and uses a bright automotive bulb. The Emergency Lantern also comes with a plug -in adapter and 16 -foot cord. Its head can tilt 120 degrees, and it comes equipped with an extra -bright krypton bulb. A red warning :31..1.,&a 2i7- flasher is built into the handle. Both lanterns come with a lifetime warranty. Price: n/a. 22 Eveready ALtomotive Lanterns CIRCLE 69 ON FREE INFORMATION CARD

www.americanradiohistory.comAmericanRadioHistory.Com A Shocking Offer! Now you don't have to be enrolled at CIE to receive our ment. This special introductory price includes all the introductory Electronic and Electricity Lesson Modules. benefits and assistance CIE normally extends to its full This program is available for a limited time to non- time students. You'll be entitled to unlimited access to students for the shockingly low pice of only $99.50. CIE's faculty and staff to assist you in your studies via a With CIE's patented AUTO -PROGRAMMED method toll free 800 number six days a week, 24 -hour turn- of learning you will quickly learn and then master the around on grading your submitted exams, CIE book- basics of electronics and electricity and then move on store privileges, a patented learning method, reference to... DC /AC circuit theories, fundamentals of bi -polar library, access to CIE's electronoc bulletin board and a junction transistors (BJT), field effect transistors (FET), free issue of CIE's school newspaper The Electron. wiring, diagram and schematic readings, component And best of all, when you decide to continue identification, soldering techniques... and much, much, your electronics education in any of CIE's programs more. This introductory offer you'll receive full academic includes the first 39 lessons credit for successful lessons in CIE's Associate in submitted and a $100.00 Applied Science in Elec- Tuition Credit Certificate. tronic Engineering Technol- All this knowledge and ogy Degree. support will put you on the road Your commitment to CIE to understanding digital electron- ends with your payment, but ics, automotive and industrial CIE's commitment to your electronics, microprocessing success just begins when principals, computer systems, you receive your lessons, telecommunications and much, exams, binder and equip- much, more.

All This For Only!

$100.00 Tuition Credit Academic Credit 39 theory and hands -on training Free issue of The Electron lessons and exams. Build your personal burglar alarm Patented learning method Toll Free Instructor Assistance CIE electronic bulletin board 24 -hour grading privileges CIE bookstore privileges

Yes! Send me CIE's Introductory Total Merchandise: $99.50 Electronic and Electricity Lessons Ohio Residents add 7% Sales Tax: and Equipment. A7332 California Residents add 6 1/2% Sales Tax: Total This Order: Name: Shipping and Handling Charge: $5.00 Street: Apt# Method of Payment/Amount Enclosed: Personal Check or Money Order City: Master Card Visa Discover State: Zip: Card Expiration Date: Age: Phone: ( ) Signature' BOOKSTORE CHARGE BY PHONE! 1776 East 17th Street coos' Ce`ard 9 AM to 4:30 PM Eastern Time: iii:--' Cleveland, Ohio 44114 1- 800 -321 -2155 ext. 7332 23

www.americanradiohistory.comAmericanRadioHistory.Com MULTIMEDIA WATCH

By Marc Spiwak Many of us remember arrived. Legions of game quality of The 11th Hour The 7th Guest as players were disappointed. indistinguishable from that being one of the best multi- What was taking so long? of a N show or movie. The media games to date. The game is to have instant 7th Guest took place in an TOPPING THE BEST responsiveness and speed, eerie haunted mansion It's always hard to top the and will run at 30- frames- where the player had to best, and The 7th Guest was per- second in full- screen solve the mystery of the one of the best. With multi- video -not just in a small house and its deceased media technology accel- window. There will be 65 Worth the owner, toy maker Henry erating at such a frantic minutes of full- motion video Stauf. The game would pace, and all multimedia in all, and audio will be CD- Wait keep a person busy for products continually im- quality. weeks on end playing it. proving, Trilobyte, Inc. had It takes a lot of data to

That was the only problem I to make The 11th Hour even make a multimedia game had with the game, that it better than The 7th Guest, of this magnitude. The 11th was too much game for me and not simply just as good. Hour is twelve times the size

to finish in the free time I The 11th Hour should fi- of The 7th Guest. Trilobyte have, Others, however, nally be released by the got it to fit on two CD -ROMs,

thought that it was the best time you read this, and I even though it is 134 gi- hope to take a look at it gabytes uncompressed - before then. The main rea- that would normally fill son its release has taken so nearly 200 CD -ROMs. Clear- long is that most of the ly something had to be technology that enhances done, so Trilobyte set out to the installation and playing develop its own compres- of the game did not exist sion schemes. when its development and Encode, Trilobyte's pro- production phase began. prietary software tool, The game will be a story- allows compression ratios telling thriller with multiple far greater than MPEG, but endings, and not just an does not require any spe- interactive movie. Through- cial hardware for playback. out the game, puzzles Even with the newly de- related to the thriller, but veloped compression It's been a long wait, but The 11th Hour, the sequel to The 7th able to stand on their own, techniques, it would have Guest, is expected to be out by the time you read this. will help the player unlock taken years to compress bits and pieces of the story. nearly 200,000 frames of game ever, and played it The story will be divided video, so the animations through to the end, solving into five acts, and solving were run on a number of its many mysteries. the final puzzle in each act computers simultaneously The 7th Guest played well reveals the completed tale within a NEXTSTEP Dis- on most PCs, its graphics to that point. At the end of tributed Computing were superb, and there was the final act, the player will Environment (DCE) network. obviously enough action decide how to end the Another problem that there to keep millions of story. All throughout the can plague multimedia game players happy. But game's development, the software is a difficult in- where was the 'ong- intended content and how stallation process for the awaited sequel? After a it would be delivered was game player. The 11th Hour few false starts, it was what drove the tech- will automatically retrieve rumored that The 11th Hour nology's evolution. configuration information would be released in Oc- One of Trilobyte's goals from the machine on which 24 tober '94. But it never was to make the video it is played, so no one

www.americanradiohistory.comAmericanRadioHistory.Com is that it should have any trouble others. The game takes you you will not be happy with in the latter combo larger getting the game to work. to the radioactive streets of the game's performance features slightly elements. Will The 11th Hour be worth post -World- War -III San Fran- on such a machine. In- speaker deed, the documentation To be more precise, I the wait? I think so, consid- cisco, where you follow the the Reference ering how good The 7th exploits of a down- on -his- that came with the game evaluated the "A" mean- Guest was, and how much luck private eye, Tex Murphy, recommends a 486 DX2/66, 10A speakers, 16 MB ing that they come with a more work is going into The as he unravels a series of local -bus video, and (The 11th Hour. We're all anxious seemingly unrelated myste- of memory, and suggests 20 -watt amplifier. Reference 30A to see what The 11th Hour ries that eventually lead to that the game will perform equivalent come with brings. a crime of timeless horror. even better on a Pentium. speakers also 20 amplifier.) It is an understatement to The documentation in- the same -watt The 10 speakers ANOTHER BIG ONE say that this game is big. cludes a card that explains Reference -inch tweeter While I'm on the subject Two years and $2.5 million why the memory is needed contain a 0.5 mid -bass speak- of big games, I've got an- dollars in the making, the and illustrates a typical and 3 -inch er enclosed in a wood other one for you. Under a game is over 2.4 gigabytes game scene on a system the 30s have Killing Moon, from Access in size, includes 3.5 hours of with 4 MB and on one with cabinet, while the game a 1 -inch tweeter and a 5- Software, is billed as an video sequences, and 16 MB. That said, mid -bass driver. "interactive movie." UKM comes on four CD's! You'll performed fine on a 486 inch MB, One of the most impor- features a number of well - also need a big computer DX2 /60 with 8 although that any good known actors including to get the big results. While between -scene transitions tant features have is a Brian Keith, Margot IGdder, the minimum requirements could have been speedier. speaker should The ProSound Russell Means, and James seem modest enough On the plus side, installa- solid cabinet. have wood cab- Earl Jones, along with 25 (386/25 MHz, 4 MB of RAM), tion was a snap (relatively), speakers the richness of the detail inets. When I first looked at made for a stunning visual the Reference 10s, although experience, and the total they were extremely heavy freedom of movement for their size, I couldn't see within the game lets you how they were made of explore every inch, includ- wood because there were ing the ceilings and the no visible seams or joints. floors, of the virtual world it Upon further reading of the

presents. To be honest, I manufacturer's literature, I haven't gotten that far into learned that the cabinets the game, but so far the are made of medium -den- puzzles are challenging sity fiberboard, assembled enough without being to tight tolerances with ep- needlessly difficult to solve. oxy cement, sanded If you dó get stuck, an on- smooth to remove seams, line hint system is available. painted, sanded again, If you have the hardware, and painted again. All I can Under a Killing Moon is a say is that they are rugged, must have. If you don't, it's a heavy cabinets, and that great excuse to upgrade! goes a long way toward producing excellent sound. SUPERB SPEAKERS The SW300 subwoofer is We have some more soft- about a foot tall, and very ware to cover this month, heavy; it made with the but first I'd like to report on same type of construction one of the best multimedia as the Reference 10s. The speaker setups I've seen 20 -watt amplifier, a small and heard so far. The stand -alone unit, connects ProSound product line from to the line -level output on a Audiophile includes speak- sound card or any other ers that are of very high audio component and to quality and are also ex- the inputs on the subwoofer. tremely versatile. I've tested The Reference 10s connect their Reference 10 /Sub- to outputs on the sub - woofer SW300 combo, and woofer, and additional be added to I was very impressed. They speakers can also offer a more expensive the setup. combo, the Reference 30/ The amplifier has a vol- This Audiophile 10A /SW300 combo has some of the best desktop ume- control knob on it 25 sound I've ever heard. SW20; the main difference

www.americanradiohistory.comAmericanRadioHistory.Com which eliminates the need If you have been consid- experience "V" at a posh for software volume con- ering purchasing high -end WHERE TO GET IT resort are dying. trols. Plenty of wire is speakers for your PC, you I've also got two new included to connect the should seriously consider Access Software discs this month from Sony speaker in any location, The these. The 10A/SW300 com- 4910 West Amelia Earhart Drive Imagesoff, and one of Salt Lake City, UT 84116 system can also be con- bo lists for $299, but one CIRCLE 50 ON FREE them features the two most nected to a regular stereo national chain, Egghead INFORMATION CARD famous personalities ever amplifier. sells it for $199. Software, Audiophile from M1/, Beavis and Butt - To get the best perfor- Speakers and subwoofers 7416 Washington Avenue South Head, in MTV's Beavis and mance out of the system, it are also sold separately. As Eden Fraríe, MN 55344 Butt -Head Multimedia is important to place the far as desktop sound goes, CIRCLE 51 ON FREE Screensaver. The disc lets INFORMATION CARD speakers properly. That the 10A/SW300 combo is you play preset or means setting the sub - hard to beat. Cores Corporation customized scripts of video woofer on the floor, and The Corel Building clips pulled directly from placing the satellites on ei- NEW STUFF 1600 Carling Avenue the animated series. The ther side of the monitor, at Getting back to the soft- Ottawa, Ontario disc also includes many Canada K1Z 8R7 about ear level. When set ware, another big action/ .WAV files CIRCLE 52 ON FREE and wallpaper to up that way, the highs were fantasy game this month is INFORMATION CARD let you customize your desk- high, there was bass aplen- Dragon Lore from Mind - top with the pair of funny Creative Multimedia ty, and more than sufficient scape. If dungeons and idiots. This is 513 NW 13th Ave.. Suite 400 one $34.95. The volume for any desktop ap- dragons excite you, then Portland, OR 97209 second, The Women of plications. Games such as you'll love this game. Cen- CIRCLE 53 ON FREE Playboy, is another multi- Doom are better with a turies ago, a fellowship of INFORMATION CARD media screen -saver subwoofer, and the PC now Dragons and Knights es- Mindscape package, but this one in- doubles as a Hi -Fi CD play- caped a war -torn world 60 Leveroni Court cludes photos and video of

er in the living room. I even and joined together in a Novato. CA 94949 the women from Playboy CIRCLE have to turn it down all the beautiful remote valley, to 54 ON FREE Magazine. You can even INFORMATION CARD time. establish peace of mind make your own custom and a better quality of life. Sony Imagesoft screen -saver modules. The Broadway But today, after eons of 2400 Ave., Suite 550 disc includes magazine Santa Monica, CA 90404 peace, the most powerful CIRCLE 55 ON FREE covers, centerfolds, car- enemy knight has sworn to INFORMATION CARD toons, bunnies, artwork, and 414./Tt01111... destroy the valley. Only you Trilobyte, Inc. more, from the 1950s =MUMS OP nexetrs can restore things to what 1225 Crater Lake Ave. through the 1990s. There's moms they once were. Players Medford, OR 97504 an adults -only version and can take multiple ap- CIRCLE 56 ON FREE a mature- audiences ver- proaches to Dragon Lore. INFORMATION CARD sion; both cost $39.95. The One can fight with weap- Viacom Newmedia disc is a must -have for fans ons of steel or with intellect. 1515 Broadway of the magazine. There's over 50 hours of New York. NY 10036 And now for something gameplay with rich, 3D CIRCLE 57 ON FREE INFORMATION CARD completely productive. CD graphics and fluid anima- Creator from Corel soft- tion. Realistic sound effects ware, lets you create your and full voice support 1995, determine dealer in- own digital audio, data, or round off the game. voices, and study over 275 mixed -mode compact New from Creative Multi- reviews and road tests by discs in the Windows 3.1x media this month is the editors of Automobile environment. A CD recorder Automania, a $29.95 CD- Magazine. becomes necessary only ROM filled with automotive MTV is getting into the when it's time to make the information from the ex- multimedia action with a disc; everything until that perts at Automobile new game that feature the point is done on a PC. The Magazine. The disc con- network's unique graphics software includes an audio - tains specifications on and captures its sense of tracks editor, a data -files thousands of new cars and humor. Club Dead, from editor, a jewel -case insert trucks to help people make Viacom Newmedia, lets you editor, a photo -CD editor, the right car -buying deci- play Sam Frost, the best and more. It keeps track of sions. You can search cyberplumber in the busi- CD space used and space Sony ¡magesoft lets you through over 1600 vehicles ness, who also happens to required for new tracks. For decorate your screen with and 75,000 specifications, be a virtual reality, or "V" only $249, users can make Playboy Playmates or the view photos and video, see addict. You've been their own custom CDs, right antics of Beavis and Butt - pricing information on new plucked from jail to figure down to the artwork for the 26 Head-you decide. and used cars from 1977 to out why people who try to jewel box.

www.americanradiohistory.comAmericanRadioHistory.Com What Do These Prestigious Companies Have In Common?

AIPANY OF Leadership in electronics is not Aerovox. just a matter of designing mnRafa products better and DC Film and RFI Suppression Capacitors, Aluminum manufacturing them better, but Caparison. Variable Capacitors and Electrolytic and A( Oil Capacitors, EMI filters Dale Electronics, Inc. Fixed Ceramic Resistors, Crystal Oscillators, Ceramic Filters, also of marketing them better. Resistors, Networks, Oscillators, Displays, Resonators, EMI Filters, Hybrid Circuits and more. Inductors, Thermistors, Connectors, & And the sponsors of this Transformers AMP Panasonic message understand that better Electrical/Electronic Connectors, IC Sockets, Industrial Company service to customers requires DINDUSTRIES. INC, PCB Switches Resistors, Resistor Networks, Ceramic, film, effectively involving distributors Batteries Computer. Cordless Phone, Laptop, Electrolytic, Double Layer Capacitors, Scanner, Alarm and Medical Potentiometers, Switches, Inductors, Filters, as part of their marketing Antenna :: Cordless Phone and Scanner Resonators, Varistors, Thermistors M teams. RAD Engineering, Inc.

Motor Run Capacitors, HID Lighting Capacitors, WIRE ANI) CABLE Philips Components naiv Ai.+ti ci Distributor involvement means Elecf,cr,C] Nor, Co,u,ai Power Factor Correction Capacitors

Resistors, Ferrite Components lower prices, quicker deliveries, Alluminum Electrolytic, Film & Ceramic Capacitors better service over -all. The E:TN Buyer wins...the Seller wins. Eaton Corporation, Commercial They sell Miniature and Subminature Coaxial & Military Controls Operation Distributors help achieve Connectors and (able Assemblies. through Switches, Relays. Displays and Keyboards distributors. marketing leadership. So does /..\SAX CORPORATION the manufacturer's involvement in the Components Group of MCC, Tantalum and Thin Film Capacitors, Resistors, Ati\ They belong Networks. Integrated Passive Components. ELECTRONICS the Electronic Industries Trimmers, Oscillators, Resonators, Filters, Pieto Quarts Crystals, Clock Oscillators, Surface Mount to the E.I.A. EIA fosters better Devices, and Connectors Products. Programmable Devices Association. industry relations, coherent A They belong industry standards, and the BERG' GERNSBACK 011 your RuBL 'CATION sharing of ideas, which helps High Density and Industry Standard Itiadlegmis vendor list. Electronics Now Magazine one another and serves Connectors/Subsystems Quam customers better. CAROL GUARDIAN In choosing your component Loudspeakers and Commercial Sound Products Electronic and Electrical Wire and Cable and supplier, look for the marks of Power Supply Cords Relay. aad Solenoids R13Hfi1 leadership -- KEMET Rohm Electronics Division Resistors, Ceramic Capacitors, Electronics Corporation availability through distribution Transistors/Dioces, Opto Components and IC's

Tubing, Conduits, Hose, Sleevings, Splices, Multilayec Ceramic and Solid Tantalum membership in E.I.A. Insulation and Cable Harness Products, Power Capacitors Cords and Cordsets °071-SEIECTA Our MInstruments, Inc. XOA1 SPEER Switches, Relays, Terminals, Indicator /Pilot 70th .II Lights, LED Indicators, Test Clips, Test Leads, Inductors, CO Midtex Resi {tors, SMT Tantalum Capacitors Anniversary Cable Ties and Heat Shrinkable Tubing Resistor Networks, SMT Thermistors Relays and Solenoids Year

Electronic Industries Coogit MALLORY Association/Components Group 2001 Pennsylvania Avenue, N.W.. Bussmann North American Capacitor Company Tantalum Capacitors, Wet Si Foil Capacitors, 11th Floor Fuses, fuseholders, fuse Blocks, and Fuse Tantalum, Aluminums, SonaltertsR Ceramics, Resistor Networks, Resistor Capacitor 20006 Accessories Films and AC's Washington, D.C. Networks, Filters Phone: (202)457 -4930 CORNELL thvitchcraft Fax: 202)457-4985 A eryf%euat Company DU BILIER Mtron Committed to the competitiveness Connectors, Jacks, Plugs, Jackfields d Capacitors- Aluminum Electrolytics, Mica, Quartz Crystal Switches, of the American electronics Hybrid Oscillators Audio Accessories, Cable Assemblies 27 AC Oil, Film, MICA Paper and Relays producer.

www.americanradiohistory.comAmericanRadioHistory.Com MEDIA VISION RENO PORTABLE CD -ROM DRIVE CIRCLE 119 ON FREE INFORMATION CARD

Take CD -ROMs along for the ride with the Reno portable CD -ROM drive.

It seems that CD -ROM drives have ble music -CD player. The Reno comes portable music -CD player. The back become as popular in new corn - with an AC adapter, a SCSI cable, of the drive docks into a similarly puter systems as the venerable headphones, Mac and PC drivers, shaped SCSI interface /AC adapter floppy drive. As a matter of fact, the and a carrying case. that links the drive to the computer. double -speed CD -ROM drive has The Reno is a fully capable CD -ROM The docking station adds about 4 more or less replaced the 51/4 -inch drive on the desktop or on the go. For inches in length to the player. A SCSI floppy drive as a standard PC pe- desktop use, an AC adapter makes it cable connects the docking station to ripheral. Most new PCs come with a behave just like any other CD -ROM your computer. The Reno will also work CD -ROM drive and no 51/4 -inch floppy drive; for portable use, a set of M off a parallel port with an optional drive. alkaline batteries is used for power. parallel -to -SCSI adapter, although With computer users beginning to performance will likely be reduced. rely on the presence of a CD -ROM Specifications. Reno will work with a Four M batteries install in the dock- drive, the absence of one can be a PC or Mac. PC use requires a SCSI2 ing station, and two M batteries install real nuisance. Once CD -ROM be- interface card -a tiny one is avail- in the player. For portable use as a came standard on the desktop, it was able for $39 from Media Vision. Macs CD -ROM drive, Reno runs off all six only a matter of time before people have a SCSI connector built in, and so batteries, while as a music -CD player, wanted to use CD -ROMs on the go. Mac users don't need the card. Reno's it works from only the two batteries in People now want to be able to use a SCSI2 interface is more versatile than the player section. That eliminates the CD -ROM drive with their powerful lap- a proprietary interface, as the drive bulk and weight of the docking -sta- tops and portables, and maybe even can be controlled by anything with tion section, which is unnecessary for swap a CD -ROM drive from computer SCSI2 compatibility. Many sound music CDs anyway. When used as a to computer. cards contain a suitable interface. battery- powered CD -ROM drive, the Short of buying a new laptop with a The double -speed Reno drive has a six AA batteries will last about 11 hours built -in CD -ROM, which can cost a fast seek time of 180 milliseconds, with continuous use, but rarely does a king's ransom, the ideal way to do that which is faster than many other dou- CD -ROM drive run continuously. would be to have a CD -ROM drive ble -speed drives -portable or not. For fixed operation, an AC adapter that you could take along with your Transfer rate is up to 306 kilobytes per can be used to save batteries. Both laptop. But of course it would have to second. Discs load into the drive with- the player and docking station have be light and portable, battery out a caddy, which is quite conve- 13.5 -volt DC input jacks that the AC powered, and specially tailored for nient. The drive easily meets MPC adapter can plug into; the jack on the portable use. That fairly accurately level -2 specifications. It is photo -CD docking station is used when the two describes the Reno, Media Vision's and multisession compatible, and pieces are joined together. portable CD-ROM drive. As a bonus, features a 64- kilobyte buffer memory. As a music CD player, Reno has the 28 the Reno can also double as a porta- Reno is about the same size as a usual Open, Reverse, Stop, and For-

www.americanradiohistory.comAmericanRadioHistory.Com ward play controls on the front panel, "YOUR and a small liquid -crystal display. Reno is light in weight, even with the batteries installed (about one poundà. FREE The player can be shaken around ELECTRONIC pretty well while playing a music CD without skipping. An audio- output CATALOG COMPONENTS jack can be used with either the included headphones, or with a pair of Whether you order 1 part or amplified speakers. KNOCKED all 51,092...MOUSER stocks Reno is a fine CD -ROM drive, and it and...ships same day!! doesn't take up a drive bay-another MY SOCKS advantage as many of today's com- CALL... 800) 992 -9943 pact PC cases are short on drive bays to begin with. For portable use, an OFF" for your adjustable carrying case fits and protects Reno with or without the docking FREE station attached. You won't be afraid We get that sort of comment to carry the unit around when it's in the the time. People are CATALOG protective custody of the spongy rub- all ber case. impressed that our free Main St. The portable CD -ROM drive can be Consumer Information 958 North purchased separately for a list price Catalog lists so many free Mansfield, TX 76063 of $349; street prices are well under and low -cost government $300. The drive -only package in- booklets. There are more cludes an AC adapter, a SCSI cable, than 200 in all, containing a MOUSER` headphones, Mac and PC drivers, wealth of valuable ELECTRONICS a carrying case. The optional and information. sales a Stocking Locations Nation/:de SCSI adapter card for a PC is $39. The CARD unit is also available as part of a multi- They tell you how to make CIRCLE 115 ON FREE INFORMATION media upgrade package that in- money, how to save money cludes the drive, a 16 -bit sound card, and how to invest it wisely. amplified speakers, headphones, mi- They tell you about federal Earn $1000 crophone, a carrying case, and 15 benefits, housing, jobs, and A You Learn High -ROM titles; that package has a list Week While CD activities for price of $599. learning Paying VCR Repair. children. They fill you in on Reno is a good investment for any- Earn While You Learn . . . a CD- nutrition, health and much, one who doesn't already have Secrets Revealed . . . ROM drive, and who wants the added much more. Train at Home bonus of CD -ROM portability and a Our free Catalog will very If you are able to portable music CD player. Anyone work with small contemplating the purchase of just a likely impress you, too. But hand tools and pos- portable CD player might want to first you have to get it. Just sess average mechanical ability, you consider throwing in some extra bucks send your name and could earn top dol- to get a CD -ROM drive, as well. Any address to: lar part time or full way you look at it, you really can't go time. Our learn by doing method teaches you how wrong with a Reno. The many ways it Consumer Information Center to work on VCR's without boring unnecessary can be configured and used make it Department KO electronic basics. For Free Information Package Send Coupon to: as versatile as a CD -ROM drive can Pueblo, Colorado 81009 Foley -Belsaw Institute, 6301 Equitable Road, get. Kansas City MO 64120 For more information on the Reno o B« a,y) portable CD -Rom drive, contact Me- I CAsek VCR (Check or another VCR Repair, Dept. 62332 dia Vision directly at the address given HighPaying Computer Repair, Dept. 64230 below, or circle no. 119 on the Free Career TV /Satellite Dish, Dept. 31115 Field Information Card. fiï Advance VCR Repair, Dept.65043 FULE9 El Camcorder Repair, Dept. 66053 BE4SBU1> FOR MORE INFORMATION E Fax Repair, Dept. 67053 Since 1926 Printer Repair, Dept. 68052 Media Vision Name 47300 Bayside Parkway Address Fremont, CA 94538 A public service of this publication and City Tel. 510- 770 -8600 29 the Consumer Information Center of the [State Zip U. S. General Services Administration J CIRCLE 154 ON FREE INFORMATION CARD

www.americanradiohistory.comAmericanRadioHistory.Com THINK TANK

By John J. Yacono We've almost com- So far when we've talked a few minds out there, it's Technical Editor pletely covered about voltage and current, worth the effort to write. Windows Magazine resistors, so this will be the they have always been A couple of notes on the

last tutorial regarding them constant. But what if volt- THD: I used a length of 6 -32 specifically. Right after the age and current change? threaded rod with a small tutorial we'll explore letters How does that affect Ohm's nylon "clevis" (used on R/C regarding past Think Tank Law and Joule's Law? Well servos) connected to the columns. the laws are still valid, but slide -pot sliders as a push - As you know, the power they only apply to the rela- pull tuner. The pots were (heat) dissipated by a re- tionship between current, mounted in the cabinet More sistor can be found if you voltage, and power at any with the rod protruding know the amount of current given instant. through a clearance hole Readers' flowing through the resistor To indicate the imperma- in the side. Coarse tuning and the component's value nence of the variables was done in the TUNE Comments by using: (when applicable), they position, and a very fine null would have to be written in was accomplished by rotat- P = 12R lowercase. So our equa- ing a knurled 6 -32 nut on is which Joules Law. Now, tions would become: the rod in the TEST position, let's use that with Ohm's using the cabinet side as a p = i2R Law: stop for the nut. That meth- p = v2 /R od is very useful for I = V/R i = v/R measuring THD below and substitute V/R for Ito Note that the resistor's value about 1 to 2 percent. Also, get: is constant (it does not vary use a shielded cable on over time), so it's written in P = (V/R)2R the input only-the twisted upper case. Frankly, in most pair should only be used at That simplifies to: circumstances, knowing the the output to your RMS P = V2/R heat dissipated by a resistor meter. You'll love the perfor- at a given instant is not very mance of this circuit! That equation is typically useful. If the changes in Thanks again. more useful, as you usually power dissipation (really in -Skip Campisi, South voltage and current) occur Bound Brook, NJ J1 J2 C4 quickly enough, we really You and I have the same VIN 0.1 VOUT need to know the average opinion about what this col- C1' C2' +3V -*--11-1( 0 .01 .01 power dissipation required. umn is about-stimulating Averages of current, volt- the mind. Thank you for your age, and power will be next continued participation. R1 R2 R3 month's topic; for now, let's You have sent me more 1K 50052 1K read those letters. circuits than any other -- reader. The quality of your R4 THD ADAPTER work is much appreciated, 1/2 TLC272 *7.68K REVISITED too. 1% TEST Ui-a O I just wanted to thank R5 31 O O TUNE you for the nice write -up WALKMAN AMP 15.40K R6 4 1% C3' 15.40K you did on my THD adapter How can the small am- .02 1% C5 R9 (see Fig. 1) in your plifier circuit on page 31 of 0.1 10K November 1994 Think Tank =1% MYLAR -3V the December issue of column. Your final com- Popular Electronics (shown Fig. 1. This THD adapter can be enhanced by using a threaded ments were really here as Fig. 2) work? There rod to set the slide pots to precise values. That allows you to get appreciated. As a semi -re- are no bias resistors on ei- readings down to I or 2 percent. tired electronics ther base. Also, C5, which

professional at 48, I still en- bypasses R1, would bypass know the voltage across a joy seeing my letters all the highs letting only

resistor rather than the cur- published. I figure that if I very low frequencies come 30 rent through it. am successful in stimulating through. Both Q1 and Q2

www.americanradiohistory.comAmericanRadioHistory.Com v+ ion. Therefore, if you 5-12V limit- measure the current- D1 D2 ing effect of the circuit with 1N4001 1N4001 a digital multimeter that SPKR1 reads the slope of an AC SPEAKER OR EARPHONES waveform, or if you do not have a load that draws current above the circuit's INPUT { set limit, you will not detect any current drop. To date, a number of people have re- success with the Fig. 2. If a down -and-dirty audio amp is what you need, try this ported miniature unit. Among other things, it can be used to boost the circuit and I have made no output of an earphone for the hearing impaired. changes to my unit, which still functions. However, U1 PINOUT need some current flow in tually provides a good please see the next section INPUT the base to function at any high -frequency path to the for details on the types of OUTPUT ADJUSTMENT So it helps resistors used. level. I bet you've received voltage source. that. charge C2 more rapidly The earlier article was in- a lot of mail on Fig. 3. This is the soldering - R1 high frequen- correctly listed as Incidentally, I have on my than when iron controller in the buff. in 1994; it was in wish list a circuit suitable for cies are present, thus appearing The application is unusual. a traffic sensor such as the enhancing HF response. the May 1992 issue. Sorry for but functional. With the It ex- type used at traffic lights to That said, I like your car the inconvenience. component values specified, detect the approach of a sensor idea -any takers out plains the controller more the circuit should be used car. My house affords no there? And by the way, why thoroughly; however, it does with a soldering iron of 25 view to cars from my drive- don't you send in your mail- not mention the device's 1t 1tts or less. like a maximum current, which is way, so I would like to put a box circuit? It sounds cellent heatsink, though, sensing coil in the pave- worthy contribution, and I 0.7 amps. Reaching that to reduce ment to alert me to an need a letter on alarm cir- maximum requires an ex- and you will have approaching car. You also cu is to round out a column might be interested in the fact that I have equipped LOW -RF SWITCH

my mailbox with a pho- I read, with interest, your Electronic tocell and a music circuit. Think Tank column in the Now when the mail comes, February 1995 issue of Pop- Securit E6( a tune plays in the house. ular Electronics regarding Low-RF Switch (See Fig. I would appreciate a the 0,w ß, .w r note back on the amplifier 3). After finally locating the circuit. TL783 chip and assembling y Mini Long Range FM Voice (3 mi) Ultra Sensitive - I Transmitter -Dwight Eggleston, Hen- the project, I found that couldn't regulate the cur- with fine tune, range control, more! Detects dersonville, NC even whispers! FMXI Kit and Plans .$4 First, the main function of rent. Were there are any Tiny Telephone a bias resistor is to establish changes to the circuit? If FM Transmitter -- the output level of a tran- possible could you also tell ! (3 ml) - automatically operates when phone is me how much current the sistor when no signal is used. Crystal clear clarity with- fine tune and applied. Because Q1's out- circuit will handle? I range control. TELX-1 Kit and Plans $49:51 couldn't find any details put is AC coupled to Q2, Both Easy -to-Build Kits Above only $49.501 Q1's output level is unimpor- concerning the TL783 chip. tant-only its alternations Also, I can't locate your ear- Extended Play to lier article, "Soldering Iron are passed Q2. Telephone Second, Q1 does receive Controller," which was listed base current -the current as being on page 53 of the Recording System - $129.50 from the input signal. Tran- May 1994 issue of Popular - Automatic - Crystal Clear - Easy to Use - - Automatically controls sistor Q2 also receives Electronics. Connects to Any Phone records both sides of the conversation on our current via C2, provided C2 Thank you very much for and extended play recorder. Caution - check local is dis- your consideration. being charged and laws as some states require an alerting beeper. William J. Tannahill, charged. - TAP2OX Ready -to-Use System only $129.50 Whittier, CA Third, with regard to C5, if FREE CATALOG with order- or send S1.00 NH that capacitor went to The circuit prevents cur- TICK MC, VISA, Check, Cash or C.O.D. rent from going above a Send or Fax Orders to: Dept pe16 ground you'd be right, highs 1 1JNUMITED Box 719, Amherst, NH 03031 from Q1 would be specified value. It does not PO Orders: 800-221-1705 FAX 603672.5406 Tel 603673.4730 31 grounded. However, C5 ac- limit current in a linear fash-

www.americanradiohistory.comAmericanRadioHistory.Com the value of R1 to around R3 Shack circuit uses 0.2 ohms.

1.7 ohms, at 5 watts. 100 I think I would use one or 10WATT two ohms as a starting val-

SWITCH II D1 ue. Because the LM317T has

I would like to build the MR750 internal current limiting and low -RF switch mentioned on 50PIV thermal 6A overload protec- pages 29 -30 in the Febru- FROM tion, little external 15-50V TO ary 1995 Popular protection is needed. SUPPLY BATTERY

Electronics. You stated that When I started building it had previously appeared my battery charger, I used on page 53 in the May D1, but because of the volt- issue under "Soldering Iron age drop across it, which Controller." Guess what, it is Fig. 4. Keep those batteries nice and juicy all year long with this varies non -linearly with cur-

I not there! also researched trickle batten' charger. Be sure to use heavy-gauge wire for all rent, I took it out. Removing every issue from April 1994 connections. D1 causes one possible

to January 1995 and I could problem: if the charger is not find it. the pot shorted. Nonethe- ohms for R1, and a corre- connected to a battery be- Even if I find your old less, the resistor should have spondingly lower value for fore power is applied, a

article, however, I would still been denoted as a 1/2-watt R2. Sometimes smaller val- backwards current will flow have difficulty with it if the unit. The artwork was lifted ues such as 220 or 120 through U1 to charge Cl. schematic is the same as from the old article, in ohms are used for R1. Be- The LM317T does not like that shown in February. I'm which the wattage was cause the LM317T maintains backwards current! That skeptical about the wat- mentioned in the parts list a voltage of 1.25 volts be- can be remedied by con- tage of the resistor and the instead of the drawing (the tween the output and necting a 1 -amp diode pot. Following the discus- reprint of the schematic in adjust terminals, that gives between the input and out- sion of this circuit is a Fig. 3 reflects Those a current of 5 mA in R1 and put terminals of U1 section called "Label Di- changes). R2. A 12 -volt battery (connect the cathode to lemma," which states that The TL783 is actually a charger shown in the "Typ- the input terminal). Then Cl unless otherwise indicated special, floating, high -volt- ical Applications" section would charge through the on a schematic or parts list, age regulator (see the old for the 317T in the 1990 diode instead of U1. That all resistors are 1/4-watt units article for more information Radio Shack Semiconduc- diode, although offen omit- in this magazine. With 110 - on the chip's features). I tor Reference Guide shows ted, should always be used volts AC applied to the cir- would not recommend a value of 240 ohms for R1 with three -terminal reg- cuit, should the resistor using another regulator in and 2400 ohms for R2, even ulators in battery chargers values still be 1/4 -watt? its place. I got mine from though Radio Shack does or other circuits where there My other problem is that Active Electronics (Tel. not stock either value. is a possibility of a voltage

no electronic parts store in 800 -677 -8899), so give In the last few months, I on the output terminal that town can cross reference to them a call to get one. have built battery chargers is higher than that on the

a TL783 part. I have a suspi- Unfortunately, even under and power supplies using input terminal. cion that it might be a 9- or optimal conditions (see the the LM317T and other 3- Next, the value of R4 (330 12- volt -DC voltage reg- previous letter), the best you terminal regulators. The ohms) will give a current of

ulator. Am I right? I want to can do is control a 75 -watt trickle- charge voltage for a 36 mA- rather high for a use the circuit to dim a 100 - bulb with the circuit. Of 12 -volt lead -acid battery standard LED. I like to keep watt light on my ceiling fan. course you might be able should be about 13.8 volts. If LED current at or slightly Would any 1 -amp 12 -volt to piggyback Iwo such cir- 5- percent resistors are used, below 20 mA, which would DC regulator work? cuits, provided that you can the output could vary by a require a resistor of 590 I'm sorry to bother you on mechanically connect the volt, Therefore, either 1% re- ohms (the standard value all those details, but there is Iwo pots. sistors should be used, or R2 of 560 should be close limited in space my light/ should be variable. There enough). In my charger, I fan, and store -bought dim- CHARGE! are also slight differences used a 300 -mA transformer

mers are too large. I hope I I have found a circuit in between LM317T's. I would and wanted the entire 300

could fit this dimmer into Think Tank that I have prob- use a 240- or 220 -ohm re- mA available for charging, light. the Thanks, I'm waiting lems with. It was Joseph sistor for R1, and a pot so I used a low- current LED to hear from you. Gaskill's Charge It in the (either 2000 or 5000 ohms) (Radio Shack 276-044 or - George Kozar, Erie, PA June 1994 Popular Elec- in series with a 1000 -ohm similar) which is easily visible You are right about the tronics (see Fig. 4). In that resistor for R2. at a current of 2 mA. resistor wattage; however circuit, the values of R1 and My next concern is the A 7805 or 7806 regulator not because it is exposed to R2 are much larger than value of R3. Although the will also work well in this 110 -volts AC. In fact, be- are usually used with an LM317T can supply 1.5 circuit. Use the ground ter-

cause of the regulator, the LM317T. Most circuits I have amps, with a 1 -amp current minal of the 78xx as the resistor never sees more seen, and some spec the voltage drop across 10 adjust terminal, and 32 than 1.25 volts, even with sheets, use a value of 240 ohms is 10 volts! The Radio (Continued on page 81)

www.americanradiohistory.comAmericanRadioHistory.Com Be a high-paid computer service technician Train With NRI - America's #1 Choice in Computer Training Only NRI gets you inside a powerful 486DX2/66 MHz Intel -based computer NEW! YOU GET EVERYTHING YOU system you keep - giving you the 486DX2/66 MHz NEED FOR SUCCESS hands -on experience you need to Multimedia PC and work with, troubleshoot, and repair Windows 95 POWERFUL 48611X2I66 MHz INTEL -BASED today's most widely used computer COMPUTER systems. There's no more affordable Features IBM compatibility, 8 meg RAM, Pentium Overdrive -ready way to start a money -making career, mothe:board, and math coprocessor even a business of your own, as a computer service technician. r SUPER VGA COLOR MONITOR With .28mm dot pitch for high -resolution graphics and tilt -swivel base A7°-T___ Rely on the 420 MEG HARD DRIVE original -- NRI For greater data storage capacity and data access speed Over a decade ago, NRI pioneered at -home training rgefri NI EXCITING MULTIMEDIA PERIPHERALS in computer Double -speed CD -ROM servicing. Today, 4 drive, 16 -bit sound NRI offers the -4 card with speakers, only computer and reference CD servicing course FAXIMODEM with real -world Gives you access to a experiments world of on -line information using state -of -the -art f ULTRA -X DIAGNOSTIC computer equipment PACKAGE R.A.C.E.R. plug -in card and and professional diagnostic tools. computers before, NRI's interactive training QuickTech -PRO software help you detect There's no doubt about it: Working problems on virtually all IBM-compatible builds such a solid foundation of know -how machines, even if computer is 5% operational. "hands -on" with all the most sought -after and practical experience that tomorrow's technology gives you practical skills and NRI DISCOVERY LAB jobs can be yours. confidence. Performing key tests Complete treadboarding system lets you design lasting and modify circuits, diagnose and repair faults and demonstrations, you're able to see for Right from the start, hands -on reinforce DIGITAL MULTIMETER yourself how things work, what can go experiments concepts presented in NRI's bite -sized lessons. And because Professioni, hand -held test instrument for quick wrong, and how you can fix it. and easy measurements your work is reviewed by your personal WINDOWS 95 Train with and keep instructor, you know for certain that you can apply theory to real -world demands. The time- saving operating system that everyone the most advanced computer will be usirg tomorrow in home study today FREE NRI catalog tells more If the coupon is missing, write to: NRI NRI's unique training has you explore a top- Send today for your free, full -color catalog Schools, McGraw -Hill Continuing Education notch computer system and its peripherals, describing every aspect of NRI's innovative Center, 4401 Connecticut Avenue, NW, beginning with the 486DX2 Intel CPU and computer training in the up -and- coming Washington, DC 20008. Pentium Overdrive-ready motherboard. field of your choice. Your features 8 meg RAM, computer IBM is a registered trademark of the IBM Corporation. R.A.C.E.R. and OuickTech-PRO are registered trademarks of Ultra-X, Inc. 420 meg hard drive, and fax /modem to store, receive, and send huge amounts of data. SEND TODAY FOR FREE NRI CATALOG! nq' You'll also appreciate the brilliant McGraw -Hill Continuing Education Center . display of your Super VGA color monitor, 4401 Connecticut Avenue, NW, Wash ngton, DC 20008 New the drama of your CD -ROM drive and 16 -bit sound card, as well as the U Check one FREE catalog only Check for details on career courses 95. cutting -edge technology of Windows 0 MICROCOMPUTER SERVICING approved under GI Bill Plus learn to use Ultra -X professional Computer Programming LAN Specialist diagnostic hardware and software to pinpoint TV/Video /Audio Servicing Bookkeeping and Accounting problems on any IBM -compatible machine. 0 Desktop Publishing & Design Programming in C ++ with Windows Noexperience needed, Name (please print) Age NRI builds it in Studies show that jobs for computer service Address technicians will be up by 38% in the next City State Zip 10 years. Even if you've never worked with 35 LAccredited Member, National Home Study Council 1B -0795,

www.americanradiohistory.comAmericanRadioHistory.Com RETAILERS THAT SELL OUR MAGAZINE MONTHLY

Alaska Whitcomm Electronics Illinois Sylvan Wellington Co. 105 W. Dakota #106 269 Canal Street Frigid North Co. Tri State Elex Clovia, CA 93612 New York, NY 10013 1207 W. 36th Avenue 200 W. Northwest Hwy. Anchorage, AK 99503 Marvac Dow Electronics Mt. Prospect, IL 60056 Unicorn Electronics 265 -B Reservation Road Valley Plaza Alabama Marina, CA 93933 Kentucky Johnson City, NY 13790

Radio Distribuiting Supply Minuteman Electronics P.I. Burks Co. Ohio 121 East Broad Street 37111 Post St., Suite 1 842 S. 7th Street Gadsden, AL 35903 Fremont, CA 94536 Louisville, KY 40203 Philcap Electronic Suppliers 275 E. Market Street HCS Electronics Arizona Maryland Akron, OH 44308 6819 S. Redwood Drive Dalis Electronics Cotati, CA 94931 Mark Elec. Supply Inc. Oregon 2829 E. McDowell Road 5015 Herzel Place Halted Specialties Co. Norvac Phoenix, AZ 85008 Beltsville, MD 20705 Electronics 3500 Ryder Street 7940 SW Nimbus Avenue California Santa Clara, CA 95051 Massachusetts Beaverton, OR 97005 JDR Micro Devices Portland Radio Supply California Electronics U -Do -It Electronics 2233 Branham Lane 234 S.E. Grand Avenue 221 N. Johnson Ave. 40 Franklin Street San Jose, CA 95124 Portland, OR 97214 El Cajon, CA 90202 Needham, MA 02194 Metro Electronics Ford Electronics Texas 1831 J Street Michigan 8431 Commonwealth Avenue Tanner Electronics Sacramento, CA 95814 Purchase Radio Supply Buena Park, CA 90621 1301 W Beltine The Radio Place, Inc. 327 East Hoover Avenue All Electronics Carrollton, TX 75006 5675 -A Power Inn Road Ann Arbor, MI 48104 1498 Oxnard Street Mouser Electronics Sacramento, CA 95824 The Elec. Connection Van Nuys, CA 91411 2401 Hwy. 287 N HSC Electronics 37387 Ford Road Mansfield, Willy's Electronics TX 76063 4837 Amber Lane Westland, MI 48185 1636 D. Avenue Electronic Parts Outlet Sacramento, CA 95841 National City, CA 91950 Minnesota 17318 Highway 3 Webster, TX 77598 Gateway Electronics of CA Colorado Acme Electronics 9222 Chesapeake Drive 224 Washington Avenue N. Gateway Electronics of CO Virginia San Diego, CA 92123 Minneapolis, MN 55401 2525 Federal Blvd. Elec. Equipment Bank Mac's Electronics Denver, CO 80211 Missouri 323 Mill Street, N.E. 191 South "E" Street Centennial Electronics Vienna, VA 22180 San Bernardino, CA 92401 Gateway Electronics Of MO 2324 E. Bijou 8123 -25 Page Blvd. Cain Electronics Co. Electronics Warehouse Colorado Sps., CO 80909 1530 Ingleside St. Louis, MO 63130 Road 2691 Main Street Norfolk, VA 23502 Riverside, CA 92501 Connecticut Nebraska Washington Orvac Electronics Signal Electronics Supply Phil's Fun Stuff Amateur Radio Supply Co. 1645 E Orangethorpe Ave. 589 New Park Avenue 616 Broadway Fullerton, W. 5963 Corson Ave., Ste 140 CA 92631 Hartford, CT 06110 Imperial, NE 69033 Seattle, WA 98108 Say -On Electronics Electronic Service Prod. 13225 Harbor Blvd. 437 Washington Avenue New Jersey Wisconsin Garden Grove, CA 92643 North Haven, CT 06473 Lashen Electronics Inc. Appleton Electronic Dist. 21 Broadway Marvac Dow Electronics 205 W. Wis Avenue Georgia Denville, NJ 07834 980 S. A Street Appleton, WI 54911 Oxnard, CA 93030 Norman's Electronics, Inc. 3653 Clairmont Road New York Wyoming Kandarian Electronics Chamblee, GA 30341 Computrs 1101 19th Street Chris Supply 7 Great Jones Bakersfield, CA 93301 Street 2007 S. Douglas Hwy., Ste. C New York, NY 10012 Gillette, WY 82716

If you'd like to sell our magazine in your store, please circle 180 on Free Information Card. 36

www.americanradiohistory.comAmericanRadioHistory.Com BY WILLIAM R. HOFFMAN

Designi program should appear on your monitor. If you have BASIC& then start with: BASIC& a space, the filename, Lou and the enter key. Once you have the program running, simply answer the various prompts that appear on the Crosso screen by entering the data required, and the program will automatically calculate the values for the circuit components.

Some easy -to- XDES- 2.BAS. The program XDES- 2.BAS, shown in Listing 1, will pro- use programs to vide crossover- circuit values for first -, help you create second -, and third -order networks (6 -, 12 -, and 18- dB- per -octave filter impressive - slopes, in that order). Figure 1 shows sounding the circuits and component designa- speaker designs.

Designing loudspeakers might information about your drivers, and seem like an occult art to might require actual measurements those who are not initiated in of a speaker's frequency- response, the techniques used There's obviously impedance, and its voice coil's DC a lot more involved than just hooking resistance and inductance values. If up a few drivers together and apply- you purchase raw drivers from one of ing a signal. Now, with the help of the the more reputable sources, you simple computer programs pre- might find that they can provide you sented here, you can lift the veil of with much or all of that information, mystery from the practice of loud- making use of these new programs a speaker design, and create terrific - lot easier. Now, let's proceed. sounding speaker systems of your own. Program Use. The programs in this Incidentally, this article builds upon article were written in generic BASIC, a previous one, "Design Your Own and should work with all current ver- Loudspeakers" (Popular Electronics, sions of both GWBASIC and BASICA for WOOFER February 1994), in which we took a the IBM -compatible PC. Enter the pro- B look at three BASIC programs for de- grams into your computer and save signing loudspeaker systems using a them in the directory that is used by PC. Those programs calculated the your computer for its BASIC interpreter, correct dimensions for an enclosure being sure to use all the letters, punc- for a particular bass driver, and aided tuation, and spacing exactly as in the design of a simple, speaker - shown. If you aren't familiar with BASIC, crossover network. The five programs just ask a friend who is; entering pro- in this article make it possible to de- grams is as easy as typing a letter. sign even -more -sophisticated Once the programs are entered, crossovers, as well as compensate for accessing them is also simple. If you WOOFER driver -effièiency differences, and have GWBASIC on your PC, do it like c eliminate peaks in a speaker's re- this: from the DOS prompt type Fig. I. The three crossover circuits that sponse. GWBASIC, a space, and the filename can be used with a two -way speaker Before we start, though, something of the program (for example, configuration (consisting of a woofer and should be made clear: These new XDES- 2.BAS); then hit enter. In a few tweeter) are first -order (A), second- programs will require highly accurate seconds the opening screen of the order (B), and third-order types (C). 37

www.americanradiohistory.comAmericanRadioHistory.Com LISTING 1

5 CLS 360 PRINT:PRINT " To print above information, 10 PRINT:PRINT:PRINT:PRINT use key now." 20 PRINT" A PC BASED PROGRAM TO 365 PRINT:PRINT " Do you wish to try another CALCULATE CROSSOVER" set of values?' 25 PRINT 370 INPUT" (1 =yes 2 =no, and Enter) =";F 30 PRINT " NETWORK VALUES FOR 2 -WAY 375 IF F =1 THEN 100 SPEAKER SYSTEMS" 380 IF F =2 THEN 990 35 PRINT 400 LET C1= .0796/(E *C) *10 ^6 40 PRINT:PRINT 410 LET C2= .0796/(D *C) *10 "6 45 PRINT" By William R. Hoffman" 420 LET L1= (.3183 *E) /C *10 "3 46 PRINT 430 LET L2= (.3183 *D) /C *10"3 55 PRINT " The following program computes 440 CLS crossover network values" 445 PRINT:PRINT:PRINT:PRINT 60 PRINT " for 2 -way speaker systems using 450 PRINT " The inductor /capacitor values for a either UR or Butterworth" second order" 65 PRINT " transfer functions and first thru third 455 PRINT " Linkwitz -Riley crossover at ";C "Hz orders." are:" 70 PRINT:PRINT 460 PRINT:PRINT 75 INPUT " Do you wish to continue? (1 =yes 465 PRINT" L1 = "L1" mHy." 2 =no) and Enter. ";A 466 PRINT:PRINT 80 ON A GOTO 85 467 PRINT" L2 = "L2" mHy." 85 IF A =1 THEN 100 468 PRINT:PRINT 90 IF A =2 THEN 990 469 PRINT" Cl = "C1" uF." 100 CLS:PRINT:PRINT:PRINT" 470 PRINT:PRINT CROSSOVER TYPE SELECTION" 471 PRINT " C2 = "C2" uF." 110 PRINT:PRINT:PRINT 475 PRINT:PRINT " Where the LF driver has an 120 PRINT " (1) First order Butterworth (all pass)." impedance of "D" ohms," 125 PRINT:PRINT 476 PRINT " and the HF driver has an impedance 130 PRINT " (2) Second order Linkwitz -Riley." of "E "ohms." 135 PRINT:PRINT 477 PRINT:PRINT " To print above information, 140 PRINT" (3) Third order Butterworth (all use key now." pass)." 478 PRINT:PRINT " Do you wish to try another 155 PRINT:PRINT:PRINT set of values ?' 160 PRINT " Enter number of crossover type and 479 INPUT " (1 =yes 2 =no, and Enter) = ";F order from above list," 480 IF F =1 THEN 100 165 INPUT " then . ";B 481 IF F =2 THEN 990 175 CLS 500 LET C1 =.1061 /(E *C)* 10 "6 190 PRINT:PRINT:PRINT 505 LET C2= .3183/(E *C) *10 "6 200 PRINT" CROSSOVER 510 LET C3= .2122/(D *C) *10 "6 PARAMETERS" 515 LET L1= (.1194 *E) /C *10 "3 201 PRINT:PRINT:PRINT 520 LET L2= (.2387 *D) /C *10 "3 205 INPUT " Crossover frequency is (Hz) =';C 525 LET L3= (.0796 *D) /C *10 "3 206 PRINT:PRINT 527 CLS 210 PRINT " Impedance of low frequency driver at 530 PRINT:PRINT:PRINT:PRINT the crossover' 535 PRINT " The inductor /capacitor values for a 211 INPUT " frequency is (ohms) =";D third order" 212 PRINT:PRINT 536 PRINT " Butterworth crossover at "C "Hz are:" 220 PRINT " Impedance of high frequency driver at 537 PRINT:PRINT the crossover' 538 PRINT " L1 ="Ll" mHy' 221 INPUT " frequency is (ohms) = ";E 539 PRINT " L2 = "L2" mHy" 222 CLS 540 PRINT " L3 = "L3" mHy' 250 IF B =1 THEN 300 541 PRINT" Cl = "C1" mHy" 260 IF B =2 THEN 400 542 PRINT " C2 = "C2" mHy" 270 IF B =3 THEN 500 543 PRINT " C3 = "C3" mHy" 300 LET C1= .159/(E *C) *10 "6 544 PRINT:PRINT " Where the LF driver has an 310 LET L1= D/(6.28 *C) *10 "3 impedance of"D "ohms," 320 PRINT:PRINT:PRINT:PRINT 545 PRINT " and the HF driver has an impedance 330 PRINT " The inductor /capacitor values for a of'E "ohms." first order" 546 PRINT:PRINT " To print above information, 331 PRINT " Butterworth crossover at "C "Hz are:" use key now." 335 PRINT:PRINT 547 PRINT:PRINT " Do you wish to try another 340 PRINT" L1 ="Ll" mHy." set of values?' 341 PRINT:PRINT 548 INPUT" (1 =yes 2 =no, and Enter) = ";F 345 PRINT " Cl ='C1" uF." 550 IF F =1 THEN 100 350 PRINT:PRINT " Where the LF driver has an 551 IF F =2 THEN 990 impedance of'D "ohms," 990 PRINT:PRINT:PRINT:PRINT "Good listening!" 355 PRINT " and the HF driver has an impedance 999 END of'E "ohms."

www.americanradiohistory.comAmericanRadioHistory.Com tions (the values of which are calcu- each other. Therefore, the calcula- lated by the program) for a two -way tions must take that into account. Pro- speaker with a bass (woofer) and a vided that the upper crossover high-frequency driver (tweeter). Fig- frequency is at least 4-5 times the ure 1A is a first -order crossover, Fig. 1B is lower one, the calculated compo- a second -order crossover, and Fig. 10 nent values should provide a good is a third -order crossover. "all pass" type of response, similar to You might notice references to un- the Butterworth filter. familiar names in the program; let's (One important thing to note here is clear that up now. Butterworth was the that if you use the second -order de- name of a mathematician who sign, be sure and reverse the connec- showed that a particular set of math- tions to the midrange driver as the ematical coefficients will give the fast- crossover network inverts its signal est filter slope possible with both flat- phase relative to the other drivers.) in -band response and minimJm phase shift in the circuit. In speaker WOOFER Some General Rules. Here are a A design that is highly desirable, so we'll couple of things to keep in mind: First, use that filter type. Also, two engineers while a 6 -dB -per- octave crossover at Hewlett Packard whose names are (first order) can be designed with only Linkwitz and Riley noted that cascad- approximate driver -impedance val- ing two Butterworth filters to create a ues, a second- or third -order design second -order type (which is not possi- requires more -exact information to be ble directly with the Butterworth successful. That means you have to equations) will provide a more desiir- know the precise values of driver im- able flat phase and amplitude, along pedance and, in the case of a third - with a faster 12 -dB -per- octave filter order (18 -dB per octave) crossover, action. the acoustic response of the drivers used. That is because the sharper the XDES- 3.BAS. This second program filter action, the more the driver's im- is another crossover program, like pedance and frequency response XDES- 2.BAS, that also allows for filter slopes of 6 -, 12 -, and 18 -dB per octave, but this time for a more ad- WOOFER vanced three -way system. That is, we B can use three drivers: bass (woofer), midrange (sometimes called a squawker), and high- frequency (a tweeter). Input the XDES -3.BAS program from Listing 2, once again being careful to see that it is entered exactly as shown, and access it by typing either GWBASIC XDES -3,BAS or BASICA FREQUENCY XDES -3.BAS at the DOS prompt. Fig. 3. This graph shows the rising When you run the program and the impedance curve of a typical moving - opening screen comes up, simply an- coil driver in comparison to the swer all the prompts for information. corrected impedance of the same coil The program will then automatically connected to a Zobel circuit. calculate all the values of the components shown in Fig. 2 (Fig. 2A is a first - become significant. As mentioned order crossover, Fig. 2B is a second - WOOFER earlier, quality drivers from major sup- order crossover, and Fig. 2C is a third - C pliers will usually come with that information, or the information will at least order crossover). Note that the mathe- Fig. 2. Here are the three crossover be made available from the man- matical coefficients used in deriving circuits that can be used with a three - those circuit values do not exactly way speaker configuration (consisting of ufacturer. The same goes for recom- match those of Butterworth or Link - a woofer, midrange, and tweeter): they mended crossover frequencies. witz- Riley. The reason for that is that all are a first -order crossover (A), a second - Second, the impedance of the driv- passive filters of the type used as order crossover (B), and a third -order ers in a second- or third -order speaker crossovers are never ideal crossover (C). crossover system must be constant to (i.e. their effect never sharply starts make the network work correctly. Be- and ends). Because of that, the action and midrange) and the higher-fre- cause a driver's voice coil has sub- of the filter for the lower -frequency quency crossover (between the mid- stantial inductance (about 30 to 300 crossover point (between the woofer range and tweeter) will interact with µH for tweeters and 0.5 to 1.5 mH for 39

www.americanradiohistory.comAmericanRadioHistory.Com large woofers) the impedance might capacitor /resistor combination is the all commonly use. The voice coil is vary quite a bit with frequency. There- purpose of our next PC program. essentially a coil of wire and therefore fore, compensation must be added has inductance; it produces a rising to make it appear to the crossover as Driver -Impedance Equalization. impedance with frequency because if it were constant instead. Compen- Figure 3 is the impedance curve of a of inductive reactance. sating for the individual drivers with a typical moving -coil driver, the kind we So how can we make sure that a

LISTING 2

10 PRINT:PRINT:PRINT:PRINT 210 LET C3= (.023/(Z3 *X2))*10 "6 15 PRINT" A PC BASED PROGRAM TO 215 LET C4= (7.900001 E- 02/(Z1 *X1))* 10 "6 CALCULATE CROSSOVER" 220 LET L1= ((.32 *Z4)/X2) *10"3 16 PRINT:PRINT " NETWORK VALUES 225 LET L2= ((.1 *Z2)/X1) *10 "3 FOR 3 -WAY SPEAKER SYSTEMS" 230 LET L3= ((.088*Z3)/X2) *10 "3 20 PRINT:PRINT:PRINT" by" 235 LET L4= ((.32 *Z1)/X1) *10"3 21 PRINT:PRINT " William R. Hoffman." 240 PRINT:PRINT:PRINT 22 PRINT:PRINT 245 PRINT " Crossover values are:" 25 PRINT " The following program calculates the 250 PRINT:PRINT" Cl = "01" uF." inductor and capacitor" 251 PRINT:PRINT " C2 ='C2" uF." 26 PRINT " values for first thru third order 252 PRINT:PRINT" C3 ="c3" uF." crossovers for a 3-way" 253 PRINT:PRINT " C4 = "C4" uF." 27 PRINT " speaker system." 254 PRINT:PRINT " L1 = "L1" mHy." 30 PRINT:INPUT " Do you wish to proceed? 255 PRINT:PRINT" L2 = "LZ' mHy." (1 =yes 2 =no) and Enter ",A 256 PRINT:PRINT" L3 ='L3" mHy." 31 ON A GOTO 35, 990 257 PRINT:PRINT " L4 = "L4" mHy." 35 PRINT:PRINT:PRINT 258 PRINT:PRINT " NOTE: midrange driver 40 PRINT " What order of crossover do you must be wired out -of- phase" wish ?" 259 PRINT " to correct for phase inversion by 42 INPUT " (first =1, second =2, third =3) and crossover network." Enter? ",B 260 PRINT:PRINT " To print the above 43 PRINT information, use key." 45 PRINT:PRINT " Crossover frequency from 270 PRINT:PRINT " Would you like to try low frequency driver to" another set of values ?" 46 INPUT " midrange driver is (Hz) _ ",X1 275 INPUT " (1 =yes 2 =no) and Enter? ",Y 47 PRINT:PRINT " Impedance of low 295 ON Y GOTO 35, 990 frequency driver at "X1 "Hz is " 400 LET C1= (.11/(Z4 *X2)) *10 "6 48 INPUT " (ohms) = ",Z1 402 LET C2= (.29/(Z4 *X2))* 10 "6 49 PRINT:PRINT " Impedance of midrange 404 LET C3= (.083/(Z3*X2)) *10 "6 driver at "X2"Hz is" 406 LET C4= (.33/(Z2 *X1)) *10 "6 50 INPUT " (ohms) _ ",Z2 408 LET C5= (.99/(Z2 *X1)) *10 "6 52 PRINT:PRINT " Crossover frequency from 410 LET C6= (.21/(Z1 *X1)) *10 "6 midrange driver to" 412 LET L1= ((.12 *Z4)/X2) *10 "3 53 INPUT " high frequency driver is (Hz) = ",X2 414 LET L2= ((.062 *Z3)/X2) *10 "3 54 PRINT:PRINT " Impedance of midrange 416 LET L3= ((.027 *Z3)/X2)* 10 "3 driver at "X2 "Hz is" 418 LET L4= ((.36 *Z2)/X1)* 10 "3 55 INPUT " (ohms) _ ",Z3 420 LET L5= ((.22 *Z1)/X1) *10 "3 56 PRINT:PRINT " Impedance of high 422 LET L6= ((.086 *Z1) /X1) *10"3 frequency driver at "X2 "Hz is" 425 PRINT:PRINT:PRINT 57 INPUT " (ohms) _ ",Z4 430 PRINT " Crossover values are:" 60 IF B =1 THEN 100 431 PRINT" Cl = "01" uF." 61 IF B =2 THEN 200 432 PRINT " C2 = "C2" uF." 62 IF B =3 THEN 400 433 PRINT" C3 = "C3" uF." 100 LET C1= (.16/(Z4 *X2)) *10"6 434 PRINT " C4 = "C4" uF." 110 LET C2= (.53/(Z2 *X1)) *10"6 435 PRINT " C5 = "C5" uF." 120 LET L1= ((.047 *Z3) /X2) *10"3 436 PRINT " C6 = "C6" uF." 130 LET L2= ((.16 *Z1)/X1) *10 "3 437 PRINT " L1 ="Ll" mHy." 150 PRINT:PRINT:PRINT 438 PRINT" L2 = "L2" mHy." 155 PRINT " Crossover values are:" 439 PRINT" L3 = "L3" mHy." 160 PRINT:PRINT " Cl ="C1" uF." 440 PRINT" L4 = "L4" mHy." 16 PRINT:PRINT" C2 ="02" uF." 441 PRINT " L5 = "L5" mHy." 170 PRINT:PRINT" L1 ="Ll" mHy." 442 PRINT " L6 = "L6" mHy." 175 PRINT:PRINT " L2 ="L2" mHy." 450 PRINT:PRINT " To print the above 180 PRINT:PRINT " To print the above information, use key." information, use key." 460 PRINT:PRINT " Would you like to try 185 PRINT:PRINT " Would you like to try another set of values?' another set of values ?' 465 INPUT " (1 =yes 2 =no) and Enter? ",Y 190 INPUT " (1 =yes 2 =no) and Enter? ",Y 470 ON Y GOTO 35, 990 195 ON Y GOTO 35, 990 990 PRINT:PRINT " Good listening!" 200 LET C1= (7.900001E- 02/(Z4 *X2)) *10A6 999 END 205 LET C2= (.31/(Z2 *X1))*10 "6 40

www.americanradiohistory.comAmericanRadioHistory.Com crossover has a constant impedance electronic components in parallel as "corrected impedance." instead? Many years ago, an engi- with it. The program, ZOBEL.BAS After entering the ZOBEL.BAS pro- neer by the name of Zobel showed (shown in Listing 3), will give us a set of gram, run it as you did with the others, that it is possible to make a circuit values for a resistor /capacitor series and follow the prompts. The voice - operate as if it has a constant imped- combination that will do just that. That coil's DC resistance and its induc- ance by adding a series network of will give the result in Fig. 3 that is shown tance can usually be found in the manufacturer -supplied specifications. If the information is not there, or if

LISTING 3 it's not available, the values can be measured using an ohmmeter and 10 PRINT:PRINT an inductance meter. The values that 15 PRINT" LOUDSPEAKER ZOBEL DESIGN PROGRAM" 20 PRINT:PRINT:PRINT 25 PRINT" by AMP 30 PRINT ZOBEL William R. Hoffman" 35 PRINT" CIRCUIT 40 PRINT:PRINT:PRINT 45 INPUT " Proceed? (1 =yes 2 =no) and Enter ",A CROSSOVER 50 ON A GOTO 60, 990 60 PRINT:PRINT:PRINT 65 INPUT " Driver voice coil DCR is (ohms) = ",R more 70 PRINT Fig. 4. A Zobel circuit is nothing 75 INPUT " Driver voice coil inductance is (millihenries) = ",L than a capacitor and resistor connected 76 LET L= L*10 ^ -3 in parallel to the driver's leads. 80 LET R1 =R "1.2 85 LET C= (L/(R1 ^2))`10 ^E DRIVER 90 PRINT:PRINT:PRINT SERIES R 100 PRINT " Series resistor- capacitor combination in parallel" 1M 105 PRINT " with the driver voice coil is:" 2 PARALLEL R 110 PRINT:PRINT:PRINT 115 PRINT " R = "R1 "ohms" 120 PRINT:PRINT 125 PRINT " C = "C1 "microfarads" Fig. 5. These two resistors, one in 126 PRINT:PRINT " To print above values, use key" parallel and one in series with the 127 PRINT:PRINT:PRINT driver, make up the attenuator circuit. 130 PRINT " Would you like to try another set of values ?" 135 INPUT " (1 =yes 2 =no) and Enter ",B 140 ON B GOTO 60, 990 990 PRINT:PRINT" Good listening!" 999 END

LISTING 4

100 PRINT:PRINT:PRINT 110 PRINT " DRIVER RESISTIVE ATTENUATION" FREQUENCY 115 PRINT:PRINT " CALCULATION PROGRAM" Fig. 6. This graph shows the parameters by" 120 PRINT:PRINT:PRINT" for determining the upper - and lower - 125 PRINT:PRINT " Wiliam R. Hoffman" frequency ranges of an audio peak. 130 PRINT:PRINT " Do you wish to continue?" 135 INPUT " (1 =yes 2 =no) and Enter. ",B 140 ON B GOTO 200, 990 the program calculates will be for the 200 PRINT:PRINT:PRINT capacitor and resistor shown con- 210 INPUT " Driver average in -band impedance (ohms) = ",Z nected to he black diagram in Fig. 4. 215 PRINT PRINT " Required attenuation, in dB, as a negative" 220 -Level Matching. Not all 230 INPUT " value (i.e. -3dB) = ",A Driver 300 LET R2= (10 ^(A /20) *Z) /(1- (10 "(A /20))) speaker drivers are matched in their 310 LET R1= Z- (1/R2 +1 /Z) ^ -1 efficiency (or more properly, sen- 320 PRINT:PRINT:PRINT sitivity), with the result that a system 400 PRINT " Resistor in series with the driver is = "Rl" ohms" might not have flat frequency re- 410 PRINT:PRINT sponse. Typically, a tweeter or mid- 420 PRINT " Resistor across the driver voice coil is = "R2" ohms" 430 PRINT:PRINT range is several dB more sensitive 440 PRINT " To print the above values, use key." than a woofer, wiich will make the 450 PRINT:PRINT " Do you wish to try another set of values?' sound of a system very "forward" or 460 INPUT " (1 =yes 2 =no) and Enter. ",C "bright." Check and compare the 470 ON C GOTO 200, 990 driver -sensitivity specifications using 990 PRINT:PRINT " Good listening!" 999 END the data supplied by their manufacturers, or use a small sound -level 41

www.americanradiohistory.comAmericanRadioHistory.Com shown in Fig. 5). That circuit arrange- LISTING 5 ment keeps the apparent load impedance of the crossover network the 100 PRINT:PRINT:PRINT same as that of the driver alone. 110 PRINT " PARALLEL ELEMENT TRAP FILTER" 120 PRINT:PRINT " CIRCUIT CALCULATION PROGRAM" Therefore you don't have to go back 125 PRINT:PRINT:PRINT and recalculate any crossover -com- 130 PRINT" by" ponent values. If the required resistor 135 PRINT:PRINT" William R. Hoffman" values are odd, simply use the nearest 140 PRINT:PRINT:PRINT standard value available, or a com- 145 PRINT " To calculate a parallel L/C/R filter that will 150 PRINT " selectively reduce a band of frequencies in the" bination of resistors in either series or 155 PRINT " output of the loudspeaker." parallel to get the necessary value. 160 PRINT:INPUT " Proceed? (1 =yes 2 =no) and Enter? ",A Exact values are not usually required ON A GOTO 200, 990 165 as the application is not very critical; 200 PRINT:PRINT:PRINT however, be sure the resistors have an 210 PRINT " What is upper -3dB frequency of the peak to be 220 INPUT " reduced (Hz) ? ",FH adequate power rating, because 230 PRINT:PRINT quite a bit of current might be flowing 240 PRINT " What is lower -3dB frequency of the peak to be" through them. For a tweeter, use at 250 INPUT" reduced (Hz) ? ",FL least a 5 -watt unit, and for a mid- 300 LET B =FH -FL range, use a resistor rated at 10 watts 310 LET FM= (FH +FL) /2 320 LET C= .03/FM or more. If you encounter a situation 330 LET L= .023 /((FM ^2)'C) where the woofer is more efficient, 340 LET R=1/(6.28*C*B) never "pad it down" with resistors be- 350 LET C1= C "10 ^6 cause that will reduce the amplifier's 360 LET L1= L *10 ^3 damping effect upon its bass reso- 370 IF L1 >8 THEN 380 ELSE 400 nance, likely a 380 LET R =R -.5 and create muddy 400 PRINT:PRINT bass sound. In that case, start over 410 PRINT " The parallel L /C /R network values are:" with either a less- efficient woofer, or a 420 PRINT:PRINT" L = "L1" mHy." more -efficient tweeter. 430 PRINT:PRINT " C ='C1" uF." 440 PRINT:PRINT " R = "R" ohms." Smoothing the Sound. Our last pro- 450 PRINT:PRINT " NOTE: this network is wired In series with the driver." 455 PRINT:PRINT" To print the above values, use key." gram, TRAPFIL.BAS, can be very useful 460 PRINT:PRINT " Would you like to try another value?' if a driver is discovered to have a peak 470 INPUT" (1 =yes 2 =no) and Enter. ",C in its response, especially if that peak 480 ON C GOTO 200, 990 happens to be in the mid range, 990 PRINT:PRINT" Good listening!" where the ear is most sensitive. TRAP - 999 END FIL.BAS designs a trap filter that can

TRAP ATTENUATION FILTER CIRCUIT

TWEETER

DRIVER

Fig. 7. A trap filter contains three TRAP ATTENUATION ZOBEL AMP CROSSOVER components-a capacitor, a resistor, and FILTER CIRCUIT CIRCUIT an inductor-in series with a driver. MIDRANGE meter like the inexpensive one from Radio Shack (part no. 32- 2050), and an oscillator or tape with test tones on TRAP ZOBEL it to determine each driver's sensitivity. FILTER CIRCUIT Then, to compensate for the level dif- 1--(4 ferences, use two resistors to form a WOOFER voltage divider that will reduce the Fig. 8. This block diagram shows the proper way to make all the speaker circuits input power to the more sensitive driv- described in this article work together. er. Calculating those resistor values is done in our next PC program: DRIV- swer the prompts asking for the driver "notch out" or attenuate a small band ERAT.BAS, shown in Listing 4. Enter that impedance and attenuation re- of frequencies in the speaker's re- program into your BASIC directory, quired, and it will calculate the values sponse. Enter the TRAPFIL.BAS program and load it as you did the others. of series and parallel resistors needed shown in Listing 5 and run it. 42 Once the program is running, an- (the placement of those resistors is (Continued on page 93)

www.americanradiohistory.comAmericanRadioHistory.Com The first thing that everyone Our design is easy to build, notices about a big, expensive stereo or home-theater speak- inexpensive, and a great way er system is always the bass. Whether to add oomph to your stereo you're listening to the sound of a giant pipe organ, or the footsteps of the T. or home -theater system. Rex in Jurassic Park, it's always the bass la\III that makes the sound so exciting! o So, does your own speaker system provide you with all the bass that you -o. want? If your answer is no, then how

73 1 2) T m about making some changes to your BY WILLIAM R. HOFFMAN O system so that it does! By building the Subwoofer described in this article, it is possible to get all the extra bass you could possibly use in an average -size living room or den. Best of all, you can build it for less than $50, and in about an evening.

About the Subwoofer. Figure 1 contains two graphs that display the performance of the Subwoofer. The graph in Fig. 1A is the actual frequency response of the unit (measured Build a PC FFT and a with -based analyzer condenser microphone) in a room of about 1600 cubic feet, with the known standing waves and sonances of the room eliminated. Note the flat re- a solid 35 Hz ubwoofer sponse down to -the system will have little trouble meeting mensions, taken from the require- mize any possible standing waves the frequency- response requirements for a box with 1.8 cubic feet of within the enclosure. ments of the current THX/Dolby home - interior volume, was chosen to mini- Supports that raise the cabinet theater standards! about 3 inches above the ground are Shown in the graph in Fig.1B is the also required. Those can be rubber maximum, continuous sound -pres- feet, short blocks of wood, or even sure level that the system is capable nicely carved rounded feet with brass of: 105 dB SPL above 35 Hz and more or plastic glides. That's up to the build- than 100 dB at 28 Hz, with both reader. Finishing of the system is also up to ings taken at a 1 -meter distance from the builder. The cabinets can be ei- the system. Again, those are definitely ther covered with veneer in a finish to 20 40 60 80 100 200 up to home -theater standards! (For match the furniture in the room, or FREQUENCY Hz) additional information on the woofer else given a painted finish. The au- used in the unit, see the "Subwoofer A thor's prototype Subwoofer was

Specifications" box.) LLI finished with textured, interior house point that matched the color scheme co 0-0-105 The Cabinet. Let's begin by looking wá of the room it was intended for. at the general assembly of our system. o>w100 Figure 2A shows the construction of zuj Construction. The process of build- 95 the cabinet itself. It is a simple rec- o ing the Subwoofer, as described here, ca tangular box that measures about 1 x is simple enough so that even the 20 40 60 80 100 200 11/2 x 2 feet, and is made from Yo- most amateur of wood workers can inch -thick chipboard material. The FREQUENCY (Hz) probably build one or more of them. Simple "butt joints" are used through- bass driver is placed on the cabinet's B bottom side behind the larger hole out the design. But that is not meant to Fig. I. This graph (A) shows the prevent more- advanced cabinet shown in Fig. 2B, and faces downward frequency response of the unit; note the builders from using other woodwork- toward the floor. As shown in Fig. 2B, flat response down to 35 Hz. That the Subwoofer is a vented system, with response, along with the speaker's ing methods. Provided that the interior the ducted port cut adjacent to the maximum continuous sound - pressure volume and shape of the enclosure woofer. In addition, the aforemen- level (B) is up to home -theater remains as specified, mitered, tioned particular set of physical di- standards! dovetailed, or even routed corners 43

www.americanradiohistory.comAmericanRadioHistory.Com SIDE 16 INCHES

END

23-1/2 INCHES

10-1/2 INCHES

23-1/2 INCHES

9 N` ALL MATERIAL IS 3/4-INCH CHIPBOARD (SEE TEXT)

INCHES H-5 --I BOTTOM DETAIL 10 INCHES

SEE TEXT B

Fig. 2. When assembling the cabinet (A), attach the top and bottom pieces last, as they must be inserted flush with the side and end 44 pieces. As the bottom detail shows (B), two holes must be cut -one for the speaker and one for the port -tube vent.

www.americanradiohistory.comAmericanRadioHistory.Com PARTS AND MATERIALS SUBWOOFER SPECIFICATIONS LIST FOR THE SUBWOOFER TO 8-INCH DRIVER Note: All wood material is 3/4 -inch AMP WOOFER Cone: 8 -inch diameter thick chipboard, plywood, or Voice coil: 1.5 -inch diameter similar material; see text. Magnet weight: 20 ounces 'SEE TEXT Nominal impedance: 6 ohms (2): 101/2 x 16 End pieces inches Fig. 3. Here's how to wire the low -pass Resonance frequency: 26 Hz Side pieces (2): 231 x 16 inches with the speaker. It Sensitivity: 88 dB@1W /1M Top and bottom pieces: 23' x 9 inductor in series inches can be placed either inside or outside of ENCLOSURE Low-pass filter (see text) the cabinet. Enclosure type: vented, 4th order 8-inch woofer (see text) Tuning frequency: 33 Hz Two- position pushbutton terminal ameter. With the tube on hand, cut Internal volume: 1.8 cubic feet (Radio Shack part no. 274 -315) and file the cabinet's bottom panel 2%s -inch diameter, 3- inch -long port SYSTEM tube (see text) until the tube just slides into the hole. 3d8 frequency: 31 Hz Wood glue, 2 -inch finishing nails, When the cabinet is actually as- Frequency response ( ± 3dB): 29 Hz to 3/4 support legs (see text), -inch sembled, the port tube will protrude > 1 kHz wood screws, 18 -gauge 2- into the Subwoofer cabinet. Maximum continuous SPL: about wire, solder, conductor hardware, 105 dB above 35 Hz etc. Now it's time to assemble the Sub - woofer cabinet. Because all of the en- Power capacity: 50 watts RMS, 70 watts maximum Note: The following are available closure joints are butt type, they can from Parts Express (340 E. First be assembled by applying a thin line 45402; Tel. St., Dayton, OH of wood glue along the surfaces to be 800 -338- 0531): An 8 -inch Thruster air leaks occurring. woofer, part no. 290- 053- $26.80; joined. After the pieces are carefully fit possibility of small a port tube, part no. 260 -322-72 together to make sure they are That is important, as leaks will cause cents; any of the inductor coils straight, finishing nails will be used to the enclosure to be tuned improperly, mentioned in the text -call for hold the wood pieces together. Let's affecting the system's performance. prices. Shipping costs vary by use to assemble the Now you are ready to mount the region and type of delivery chosen; that technique please contact Parts Express for cabinet in the following order: woofer and make the wiring connec- more information. Attach one of the side panels to an tions. Pick a place on the enclosure's end piece; consult Fig. 2A. Note that in bottom, preferably near where the the cabinet assembly, the side pieces woofer mounting hole is, and install a can be used to make the cabinet's are fitted in between the ends. That terminal block. Drill the necessary corners. Also, solid wood material, or makes up the four walls of the box. holes for the electrical connections plywood, as long as it is 3/4 inches thick, When those are glued and nailed to- on the enclosure's bottom, and after can be used instead of chipboard In gether, insert the top and bottom soldering some short lengths of 18- addition, extra internal cabinet brac- panels down flush with the top or bot- gauge wire to the terminals, feed ing can be added to make the system tom edges of the cabinet's walls. them through into the cabinet's inte- more rigid. For those who wish to do When fitting the top and bottom rior, toward where the woofer will be any of those things, just study Fig. 2, pieces, first nail them in place, and mounted. Also, be sure and mark draw up your own plans, and then then reach in through the woofer's which wire goes to the red or "hot" proceed! cutout and run a bead of glue around terminal on the strip. That one must go Now, let's take a look at the method the joining areas. Using your finger or to the " +" or "hot" terminal on the that was used to build the Subwoofer a rag, smooth and spread the glue woofer so that the Subwoofer and prototype, step -by -step: First, you will around until all the seams are filled. other speakers in the system will be of course have to get all the materials Also, go back over all the other cab- connected in phase. If the wires were together. The woofer, as well as other inet seams as well, and fill and seal reversed, nothing would be harmed, speaker components are available them as necessary so that there is no but less bass would result. from the source given in the Parts and After mounting the terminal strip, Materials List. Also, be sure and ar- seal around its edges (or around the range for whatever you will use for holes going through into the interior of legs to support the cabinet off the the cabinet) with more glue so that floor. everything is airtight. Solder the wires Second, cut the wood to the sizes from the terminal strip to the terminals listed, and cut the openings for the on the woofer. Mount the woofer by bass driver, and port -tube vent, as in- inserting it face out into the hole cut dicated in Fig.2B. The hole for the port for it in the cabinet. It will rest in place tube is slightly larger than 2 inches in because of its outer rim. Secure the diameter; that extra thickness is to ac- woofer by fastening a 3/4 -inch wood commodate the width of the tube it- screw through each of the mounting self, which has a 2 -inch inside The 8 -inch Thruster woofer shown here holes in the rim, making sure that the diameter, and a 21/8 -inch outside di- makes the Subwoofer really come alive. (Continued on page 92) 45

www.americanradiohistory.comAmericanRadioHistory.Com The Truth About Speaker v Cables

BY WILLIAM R. HOFFMAN

Some of them cost a lot, but does that make them any better?

Any audiophile who has ever might even cite tests and studies, out on, and the other for it to return by. seen one of those monstrous "proving" their point. So then, where Because of that, there is a difference sets of speaker cables pro- does that leave you? in potential between the Iwo adja- truding out of the back of an amplifier Well, the best bet is to decide on cent conductors, which gives the ca- and running to the nearest loud- your own if there really is a difference. ble capacitance. The currents in the speaker, might have wondered what And the best way to start is to under- two conductors, being in opposition was so important about them. Or stand just what is inside some of those to each other, cause the inductive more important, how could they be fancy audiophile cables. fields to be opposing, and therefore worth their enormous asking prices? to partially cancel each other. And then, if audiophiles look to buy a Some Cable Basics. To begin with, (Note: Low capacitance can be pair for themselves, they discover that the conductors (wires) in a cable especially important with some types there are about 60 manufacturers of- come in two basic forms: round (cir- of solid -state amplifiers that use large fering them in a bewildering array of cular cross -section) conductors, and amounts of negative feedback. Too shapes, materials, and designs! On flat (square or rectangular cross -sec- much capacitance can lead to in- top of all that confusion, is it really tion) "ribbon" types. Both those forms stability and oscillation, and can be possible to hear a difference in sound are used today by many manufac- damaging to the amplifier's circuitry) quality at all? turers, although the round conductor Now, lets move on to the cable de- Starting with the last question first, is certainly the most common. By signs themselves. To begin with, we'll try asking some of your audiophile using one of those wire types, most review those that are based on the friends what they think. It's likely that as manufacturers attempt to create a use of round conductors -the most many as you ask, you would probably cable that has low DC resistance, and common type in use today. also get the same number of different a low or selective, reactance charac- answers! Although each would likely teristic (capacitive or inductive) that Round -Conductor Cables. Cables acknowledge that differences exist, it they feel will make a stereo system using round conductors generally is doubtful that any two would consid- sound better. come in 7 basic configurations. In Fig. er the same manufacturer's product But how does a speaker cable have 1, those types of cables are illustrated as being the "best." Still no help! inductance and capacitance? Any (A through G). Let's discuss each one in Then, if you approached an "ex- current flowing through a conductor turn: pert" with questions about speaker induces a magnetic field around it- Figure 1A shows a stranded parallel cables, what could you expect to get? self; a wire is therefore said to have pair. That is the common "zip -cord- Many researchers in the electronics inductance. In a single speaker cable type" speaker wire we're all likely to and audio field would probably say there are usually two conductors, one be familiar with; part of the wire's pop- 46 there is no audible difference. They for the current from the amplifier to go ularity has to do with the fact that it's

www.americanradiohistory.comAmericanRadioHistory.Com mass produced and quite cheap. The therefore have very low values of in- conductors are stranded (usually 7 -25 ductance (because of the mutual strands per conductor), and com- cancellation effect). High frequencies monly used in 14 -, 16 -, and 18 -gauge will therefore find that the easiest sizes for a home stereo. Because it is path. While at the same time, those stranded, the wire is quite flexible and near the outer circumference will has a greater surface area than a sim- have minimized cable -to -cable ca- ple, solid- conductor type would have. pacitance, making that the easiest The circumference, and therefore the path for the low frequencies. surface area, is proportional to the Figure 1E shows a cable with multi- radius squared. Also, as we have just ple, circumferentially stranded sets discussed, the proximity of the two around a large -core conductor (a conductors affects both the capacii- variation of the design shown in Fig. tance and inductance of the com- 1C). Here, the cable is designed to plete cable assembly. The conductors have an absolute minimum of induc- are usually molded into a ther- tance. With the center, large -wire moplastic -type material, for flexibility bundle as one conductor, and the and ease of cutting and stripping. multiple, smaller -wire bundles circum- In Fig. 1B is shown a round, solid - ferentially arranged around it as the core, parallel pair. That type of wire is other, the surface area between the commonly used for household AC wir- two conductors is maximized, there- D ing, and comes in 12- through 16- fore also maximizing the mutual in- gauge sizes. Being a solid core wire, it ductance cancellation effect be- has the most conductivity for a given tween them. (The only way that could conductor outside circumference be made more effective is by creat- (there are no wire strands with air ing a cable with a single, round inner spaces between them). As far as the conductor surrounded by another other properties go, it is similar to the conductor formed as a solid circum- stranded type mentioned above. ferential shell.) The down side of that is, Some years back, 4- or 6- gauge, sol- of course, the very high conductor -to- id-core conductor cables commonly conductor capacitance. used in arc -welding rigs were used for Figure IF shows a cable with multi- audio, and some audiophiles liked ple parallel pairs, terminated at ends. them very much, despite the difficulty That design consists of multiple paral- with the stiffness and bulkiness of the lel bundles of smaller bundles of cables. Such speaker wiring certainly stranded wires. The many small wires had low DC resistance because of its make for a low DC resistance, while large cross -sectional area and dr- Fig. 1. Cables containing round the spacing of the bundles can allow cumference! conductors come in the seven basic the maker to adjust the values of in- Shown in Fig. 1C is a circumferen- configurations shown here. They are: a ductance and capacitance to any- tially distributed, stranded, multiple - stranded parallel pair (A); a round, thing desired. It's an interesting conductor cable. One of the first at- solid-core, parallel pair (B); a "universal" design. tempts at improving the standard, circumferentially distributed, stranded A cable with parallel stranded wires with a colid two- conductor parallel -pair cable multiple- conductor cable woven together as a parallel flat core (C); a radially distributed, stranded types was to up of the braid is shown in Fig. 1G. It is an inter- break each multiple- conductor cable (D); a cable loosely on the conductor -wire bundles into multiple with multiple, circumferentially stranded esting design, based smaller ones, and distribute them sets around a large -core conductor (E); parallel- conductor ribbon cables around the circumference of the ca- a cable with multiple parallel pairs, used in computers. In the only known ble surrounding an insulated, solid terminated at ends (F); and a cable with example of the flat -braid design, 36 core. That method of construction al- parallel stranded wires woven together heavy, 16 -gauge insulated wires were lowed the manufacturer to maximize as a parallel flat braid (G). woven together to form a ribbon the number of wire strands (and about 5- inches wide. Very low DC re- therefore the wire surface area), and tributed, stranded multiple-conductor sistance and minimum capacitance to keep the Iwo sets of conductors cable. With that design we have the were its features. On the other hand, apart as much as possible (reducing unique opportunity to have the low the weight and extreme stiffness of the the cable capacitance). The only audio frequencies pass through a dif- cable made it extremely difficult to slight disadvantage is that the cable ferent set of wires than the high fre- use. inductance rises because the effect quencies! Consider the arrangement of parallel inductive -field cancella- of the cable wire bundles shown in Ribbon -Conductor Cables. Figure 2 tion due to opposing currents in adja- Fig. 1D. Those near the center of the shows three (A through C) basic flat - cent conductors is reduced. cable assembly will be completely wire (ribbon conductor) cable designs. Those are usually much more Figure 1D shows a radially dis- surrounded by others nearby and 47

www.americanradiohistory.comAmericanRadioHistory.Com expensive than the simple round -wire of 0.5 to 1.2 ohms by itself. So, as long types because of the cost of the wire as we keep the speaker cable's resis- in the ribbon form, and the increased tance down to a few tenths of an cost during manufacturing of molding ohm, or less, the inductor's resistance the conductors accurately into the will make those cable losses insignifi- insulated sheathing around them. A B C cant. Lets discuss the designs in order. Fig. 2. The three basic flat -wire cable Now, let's turn to the basic resistivity Figure 2A shows a cable design that types shown here are designed to have of the metal conductor itself. If we look has ribbon conductors that are either: ribbon conductors that are at Table 2, we can see that copper spaced apart with parallel flat sides (A): spaced apart with parallel flat sides. (which is commonly available and ribbon conductors that are spaced apart That is probably the most common quite cheap) is almost as good as can with their edges closest together (B): or flat-wire cable form. The advantage be had. Only silver is better, multiple ribbon conductors per cable and then is, of course, that each conductor has (C). only slightly. But considering the cost a large cross-sectional area, yielding of silver, most manufacturers would a low DC resistance. But there are agree that using copper is just fine. TABLE 1 some definite problems with the de- What about the exotic alloys, pure sign too. The cable can very stiff be A.W.G. Resistance metals, and other "special" materials and difficult to use: it might be possi- Gauge (Ohms per Foot) used by manufacturers to eke out ex- ble to bend it in only one direction, tra performance? We'll get to them in 4 .00026 perpendicular to the large, flat sides a moment. of the conductors. Also, unless the 6 .0004

conductors are spaced some dis- 8 .0065 TABLE 2 tance high apart, capacitance from 10 .0010 wire -to -wire is possible-something Material Resistivity 12 .0016 that is definitely not desirable. (Ohms /Meter x 10) The type of cable shown in Fig. 2B 14 ;0026 Aluminum 2.7 contains ribbon conductors that are 16 .0042 Beryllium 4.6 spaced apart with their edges closest 18 .0066 Copper 1.7 together. That is a variant on the cable in Fig. 2A. By placing the ribbon con- 20 .0105 Gold 2.3 ductors with their edges (instead of Magnesium 3.9 flat faces) facing each other, cable resistance of stranded, drawn copper Molybdenum 5.7 capacitance is much reduced -a wiring (7 strands per conductor). Note Nickel 6.8 good feature to have. On the other that the sizes commonly used for hand, the cable's bending problems speaker cables, 14, 16, and 18 gauge, Rhodium 4.7 might even be worse with that design. have very low resistance: from about Silver 1.6 Another variant, shown in Fig. 2C, 2 to 6 milliohms per foot. For cable Tungsten 5,5 features multiple ribbon conductors lengths of, say, 30 feet or less, that will Zinc per cable. Unfortunately, that con- be only about a third of an ohm in 5.9 ductor arrangement has the poten- total resistance, which is probably tial to be worse than either of those small enough that it can be ignored. About Insulation Materials. we have already mentioned, com- Why? Let's look at an example for the Besides preventing electrical shorts bining the potentially high cable -to- answer. between conductors in a cable, in- cable capacitance of the cable Let's say the damping factor of the sulation has only one other significant shown in Fig. 2A, with the very stiff bass driver in our speaker system is effect: It is one of the factors that de- physical form of the cable shown in what we are most concerned about. termines the capacitance between Fig. 2B. The higher the DC cable resistance, opposing cable conductors. the poorer the damping will be, so it Conductor -to- conductor capaci- Conductor Materials. Because it is should be kept down. An audio power tance is basically determined by four very desirable to have a cable with amplifier might have an output im- factors: conductor spacing, area of the highest conductance possible, a pedance of about 50 milliohms, conductor surfaces facing each good cable should start out with a which will act like a near dead short other, potential difference, and the di- basic wire type that has the lowest (and a good "brake ") on the back electric constant of whatever is be- possible resistance. Two choices are EMF (electromotive force) generated tween the conductors (the constant possible: The first is to make the wire as by the dynamic motion of the woofer's of air is approximately 1). The first three large as possible, and the second is to voice coil. That is good because it capacitance- defining parameters use a conductor material that has as would control the driver's bass reso- are determined by a cable's physical low an intrinsic resistivity as is possible. nance, and lower its distortion. But design, so we now need to examine Taking those in order, let's start out there is one other factor here we can- only the dielectric constant. Because with conductor size, (or more properly, not forget: The crossover inductor it is desirable to keep cable capaci- cross -sectional area). Table 1 shows us, placed in series with the woofer's tance down, a material with the 48 by A.W.G. (American Wire Gauge), the voice coil might have a DC resistance (Continued on page 93)

www.americanradiohistory.comAmericanRadioHistory.Com

Random-dot images are lots of fun, and it is easier than ever to make your own.

The image that appears at the beginning of this article might appear as a random hodgepodge of color, out if you loo< at it correctly (or is it inconectly''), a 3-D image of a warrior wi-h a sword will jump out of the page. That image is an example of a Single Image Stereogram ISIS), and it is a member of a family of related images that also includes -andormdot images, stereograms, Sing e Image Random Dot Stereograms (SIRDS), 3D images, and more. Those images have become quite popular in recent year with T-shirts, posters, greeting cards, and puzzles decorated with them for sale ir stores everywhere. The images can be in black and white or n calm and can be formed from pa-terns, photographs, drawings, or any other kind of image. The trick to seeng the stereograms is to focus your eyes not on the image, but behind t. It's Ike having droplets of water cn a pair of glasses; you don't really see the drops unless you try, but you can see them Some ceople find it easier to see the image when looking at it through glaEs, and -ocusirg their eyes not on the mage but on the glass.

www.americanradiohistory.comAmericanRadioHistory.Com Seeing Random -Dot Images. There are various tricks and techniques to seeing the images. One 's to relax yourself and hold the image between 8 and 16 inches from your eyes. Get into a trance -like state, and try to "unfocus" your eyes on the image. If you are quick to pick up the technique, you`il see the image after only a few seconds. Another technique is to bring the image to the tip of your nose. Let your eyes settle into focus, then slowly move the image away without changing that focus. Some images, like the black -and- white ones that accompany this article, include two dots to aid the viewer. Before you try the dots, though, try this: Hold two fingers in front of your eyes Can you see the bull's head in this SIS image? The pattern used to form the image was and focus them on something farther supplied with the Stereolusions package. Unlike some SIS images, this one also works away. At first you should see four fin- in black- and-white. gers. If you vary your focus, the two center finger images will) overlap at top of each image are used in the to see the image, the Iwo dots should some point and you'll see the illusion same way to help focus your eyes. appear as three dots. Once you see of three fingers. The two dots at the When your eyes are prooerly focused that, the trick is to transfer your focus from the dots to the image below.

`} i . .4%, 1,7 ',.:y.. `..,a0r4-1'. How The Images Are Formed. When you look at a three -dimensional object, your brain uses the different perspective between your two eyes to judge depth. Most people have seen stereoscopic art that provides a slightly different image for each eye to give the illusion of depth. Three - dimensional movies require the viewer to wear glasses with different-col- ti+ ored filters for each eye to achieve a3,y1.9.,¿^,q the same effect. î:K R;,,,,,,.ir °r}M The random -dot images do the ? +iM i,T. , l.rMi- 9.+ drY same thing by hiding different images for each eye in vertical strips of dots. Yrr '" y} '`* 4 ,r.?r:bi .ai`!;;. -1,, The strips are as wide as the distance '::..% %... between the Iwo dots. When one eye ^1' ,a,,;dti°v ,`4 is looking at a dot in one strip, the f :.T,uÌ°TàX rle. other eye should be looking at the same dot two strips over. Sometimes you'll see some very unusual double images when one eye focuses on a dot three strips away from the other. Some people find it easier to see the image if they cross their eyes slightly.

Where You Can Get Them. If you haven't seen any of these images anywhere, it's probably because you don't go out to the shopping mauls very much; the images are everywhere. But there is also a mail -order The image of a horse, a flock of birds, and the planet Saturn are hidden in the company that specializes in these im- 50 random -square pattern of this S/RDS picture. (Continued on page 92)

www.americanradiohistory.comAmericanRadioHistory.Com COMMURICATIONS TROUBLESH0071NG LICENSING AND AND REPAIRING CERTIFICATION AUDIO & VIDEO EXAMINERIONS CASSETTE PLAYERS THE CONIWLETE & RECORDERS TAB REFERENCE

3785P 919.95 3795P $19.95 0708223-XX $44.95 Counts as 2 Hardcover

...... ViC

ANALOG AND DIEITAL C.A RO. L COMMUNICATIONS

when you join the Electronics Book Club®

4261P 624.95 0306362 $13.95 0304165 921695 Hardcover

MICROWAVE

0158773-XX 044.95 0487375 524.95 Count, as 2111adcover

ßLTLI) YOUR OWN ROBOT BUILDER'S 111ST FQCl11y1INT BONANZA 99 INEXPENSIVE 1 F ROBOTICS PROTECTS

417911 028.95 3258P $19.95 3475P $21.95 4491P 922.95 2800P 817.95 0378514 -XX 844.95 2790P 517.95 Yardcnvec Counts as 2 /Hardcover

Mt'G5 w F50 I_URCU 1 PRACTICAL ENCYCOPEDIÂ ANTENNA AND' HANDBOOK ELE+"IRJNIC Second Editln TROU'$LEINOO1fl ç COMM GUIDE, Volume nrariptm Basic Xefeence for Elects oores Ymtt Builder, Course

0376167a(X 459.50 4227P 815.95 3711P 519.95 2613P $19.95 0873784-XX $54.95 3671P 3I8.95 0111049 -XX $49.95 Counts as 2/Hardcover Counts as 2 /Hardcover Counts as 2 /Hardcover

READING SCHEMATICS As a member of the Electronics Book Club ...

you II t rt oy rece ;v1' -1g CAUL) bulleons every 3 -4 weeks containing exciting offers on the latest books in the field at savings of up to 50% of of regular puolishers' prices. If you want the Main Selection. do noth ng and it will be shipped automatically. If you want arothe- book, or no book at all, simply return the reply iorm to us by the date specified. If 380211-XXX 884 -..95 4270P $19.95 3632P $10.95 0376026 542.95 Counts au 3/Hardover Hardcover you ever receive a book you don` want due to late delivery it at You'll have TEAr-H POIIFlFI of the bulletin, you can return our expense. 'tHB GL.NT ROOK OF at least 10 days to decide. And you'I, be eligible for FREE EIECiR(CITI" ELECTRONICS BOOKS through the Bonus Book Program.Your only obliga- PROJECTS o tion is to purcnase 3 more books Bring the next 12 months, after which you may cancel your membership at any time f. shipping/handling charge and sales tax will be acdod to all orders. All books are suftcover unless otherwise toted (Publishers' prises shown.) II you select a book that counts as 2 choices, write the took number in one box and XX in the nest. It you select a book that counts as3 choices, write the book number in one box and XXX in the next 2 hoses. 1995 Electrorics Book Club PE795

It card is missing, write to Eloctrdrics Book Cite. A Division of McGraw-Hill, Inc . Glue Ridge Summll. PA 17294.0810 3279P $2695 4199H $29.95 1367P $29.95 4230H -XX $39.95 Hardcover Counts as 2/Hardcover 53

www.americanradiohistory.comAmericanRadioHistory.Com The monkeys were green, the bananas were blue, and everyone had a good laugh," according to David Sarnoff, RCA's ...The president and chairman. The "everyone" who had laughed at the 1949 demonstration of RCA's experimental, Bananas all- electronic, and compatible color - television system, however, had not included Sarnoff. At the time, the situa- Were tion had not been the least bit funny to him. That's because Sarnoff and RCA Green: were locked in battle with CBS, who advocated an electromechanical, BY P. non -compatible, color -TV system. JAMES RYBAK While in hindsight, the winner of that battle should have been obvious, in 1950 things were not so clear. In fact, after hearings and demonstrations that dragged on for eight long months, the FCC disregarded the compatibility issue and endorsed the CBS system.

What Does "Compatible" Mean? A "compatible" color -television system is one that is capable of producing, without any modification, a high - quality monochrome version of a color transmission on an ordinary black- and -white receiver. Similarly, in a compatible system, a monochrome television transmission produces high - quality monochrome images on a color receiver. If the new color system were not compatible with the existing monochrome system, the millions of monochrome receivers already in existence at the end of 1949 would have to undergo expensive modifications in order to receive the color transmis- in sions black and white. Harold B. Law led the team that developed the three electron -gun shadow -mask color - The FCC seemed not to realize that TV picture tube. the technologically outmoded CBS system, although it seemed to offer ticular "battle," the 'bear" to establish came a practical reality that could be somewhat better picture quality, was the ultimate superiority of RCA's color - enjoyed by all. performing about as well as it ever television system was far from over. He On July 3, 1928 in England, John could and was fundamentally inca- was convinced that he would have Logie Baird conducted the world's first pable of achieving compatibility with the last laugh. documented demonstration of color the then existing monochrome- televi- television. Baird also had conducted sion systems. The commissioners also The Beginnings of Color Televi- in London the first public demonstra- apparently 'did not realize that the sion. Most people are not aware that tion of a crude monochrome "televi- RCA system, in addition to already the birth of color television occurred sion" system in March of 1925. having demonstrated that it was in the late 1920s. However, the tech- Work was taking place on this side compatible with existing mono- nology did not exist at that time to of the Atlantic as well. Three months chrome television receivers, still was in produce a color- (or even mono- after Baird's 1925 demonstration of the developmental stages and clear- chrome-) television system capable monochrome television, Charles ly had the potential for greatly im- of transmitting and receiving "enter- Francis Jenkins demonstrated his own, proved picture quality. tainment quality" broadcasts. The similar, monochrome system near David Sarnoff, however, was con - American public had to wait well over Washington, DC. By 1928, there were 54 fident that while he had lost that par- thirty years until color television be- 15 licensed experimental mono-

www.americanradiohistory.comAmericanRadioHistory.Com The road to an all -electronic, compatible, color - spiral sets of holes had its own photocell detector. TV system was far from smooth. Here's a look at At the receiver, Baird also used a the people and discoveries that made such a Nipkow disk with three sets of spirals. He used two gas- discharge tubes as system possible. his light sources. One tube contained neon and provided light for the "red" spiral of holes. The other tube contained a mixture of helium and mer- cury vapor. That tube provided the light for both the "blue" and "green" spirals. Acommutatorwas used to turn The Early Days the gas -discharge lamps on and off at the proper times. That arrangement, coupled with the persistence - of Color TV of- vision effect supplied by the ob- server, resulted in sequential reconstruction of the image in recognizably appropriate colors. chrome -television stations in the U.S. the Nipkow disk increased the Researchers at the Bell Laboratories broadcasting over the airwaves at number of scanning lines and, hence, used a color -television system in 1929 various times. In June of 1929, scien- increased the amount of definition, that had some somewhat different tists at Bell Laboratories demonstrated but decreased the size of the image features from Baird's. The Bell Labora- a color -television system that was reconstructed at the receiver. tories' system was based on the "flying somewhat different from Baird's. All An identical Nipkow disk at the re- spot scanner" principle. Rather than those color and monochrome sys- ceiver was located between a neon flooding the entire scene to be tele- tems displayed only coarse images glow lamp and the surface on which vised with bright light, a carbon arc due to the type of "scanning" used. the image was to be reconstructed. lamp was located behind a rotating The intensity of the neon lamp was Nipkow disk that had only one set of What Is "Scanning ?" When a per- proportional to the intensity of the spiral holes. That caused a moving or son reads a page of printed text, all light reaching the photocell at the "flying" spot of intense light to scan the the information on that page is not transmitter. Because the rotation of objects comprising the scene. transmitted to the brain in- both Nipkow disks was synchronized, Photocells responding only to red, stantaneously. Rather, the person's the light passing through the Nipkow green, or blue light, respectively, and eyes "scan" the page, line by line, disk at the receiver reconstructed the located at strategic locations around from left to right and from top to bot- televised image, As long as the rota- the scene detected the reflected tom (assuming, of course, that the tional speed of the Nipkow disks ex- light. The selective responses of the page is written in English or another ceeded 15 revolutions per second, photocells were achieved through Western language). The video infor- and the brilliance of the image was the use of appropriately colored fil- mation to be transmitted by television kept low, the persistence -of-vision ca- ters. The outputs of those three sets of must be scanned in a similar manner. pability of the human eye and mind photocells were transmitted to the re- In the early days of television, the interpreted the reconstructed image ceiver using three separate wire cir- scanning of a scene to be transmitted as being 'flicker free." cuits. and its reconstruction at the receiver Very large, rapidly rotating Nipkow Reconstruction of the image in was achieved through the use of a disks were required to achieve even color at the receiver was accom- rotating " Nipkow" disk (see Fig. 1). The moderately high- definition, flicker - plished using a single Nipkow disk, like Nipkow disk consists of a thin, circular free images of what then was consid- that used in monochrome television, sheet of metal with a series of small ered "acceptable" size. Disks with a together with separate red, green, holes arranged in a single spiral ring diameter of approximately 40 inches and blue light sources. The intensities around the circumference. Each hole and rotating at 1200 rprn were re- of the three light sources were made in the Nipkow disk allows only the light quired to produce twenty 60 -line im- proportional to the light detected by from a designated portion of the ages per second with an image width the photocells at the transmission lo- scene to be televised to reach a pho- at the receiver of two inches. cation. The outputs of the three light tocell. John Logie Baird used special sources were simultaneously directed A scene was completely scanned Nipkow disks, each with three sepa- on the appropriate portion of the in one complete revolution of the rate spiral sets of holes, in his 1928 Nipkow disk through the use of spe- Nipkow disk. The spacing between color television demonstration. At the cially designed semi -transparent mir- the holes in the Nipkow disk deter- transmitter, the three sets of holes rors. mined the width of the reproduced were covered with red, blue, and image while height of the image was green filters, respectively. That pro- All Electronic Television. It was determined by the pitch of the spiral duced sequential scanning in the clear to many by the early 1930s that pattern of holes. Putting more holes in three primary colors. Each of the three mechanical scanning could never 55

www.americanradiohistory.comAmericanRadioHistory.Com netic deflection of the electron beam in both the horizontal and vertical directions, together with electrostatic focusing. With the IInescope and the Iconoscope, Zworykin was able to achieve monochrome television consisting of 120 lines per image and 24 images per second. Philo Farnsworth, working by himself and without the financial backing of a large corporation, was developing similar all- electronic television equipment concurrently with Zworykin. By 1930, Farnsworth had obtained patents on his "Image Dissector" camera tube and "Oscillite" receiving tube. Work on developing all- electronic television was progressing in Europe as well. However, while a definite improvement over mechanical scanning, the expensive equipment required for all- electronic television still could not produce "entertainment quality" images. One problem was the flicker associated with high -brilliance images. It was eventually found that the flicker Fig. 1. A Nipkow disk, like the one shown here, consisted of a thin, circular sheet of problems could be reduced by using metal with a series of small holes arranged in a single spiral around its circumference. a process called "interlaced scanning." With interlaced scanning, lines achieve the "entertainment- quality" literally millions of individual points of 1, 3, 5, 7, etc. are scanned first, The images necessary to make television light at the transmitter in order to result is called a "field." Lines 2, 4, 6, 8, commercially successful. In addition, achieve high -quality image definition etc. are then scanned to produce a the large physical size of the equip- at the receiver. He and his research second field. The two fields are finally ment required for reception of even associates developed a means for combined to produce a complete very small color images made me- producing a mosaic of microscopic picture, called a "frame." chanical scanning impractical for individual photocells on a mica or Work also was continuing during home use. Although John Logie Baird glass surface. the 1930s to develop a practical continued his work with mechanical The photocells converted the color -television system. The lack of scanning until the late 1930s, most of points of light from the scene into phosphors capable of producing the the research was by then being di- electrical charges proportional to the primary colors of red, green, and blue rected toward developing all -elec- amount of light received. The charges in the receiving tube, together with tronic television. were sequentially converted into numerous other technological prob- For some time, many researchers electrical impulses by a scanning lems, kept the development of all - had recognized that the ability to beam of electrons. Those impulses electronic color television consider- control a beam of electrons in a cath- then were transmitted. Zworykin ably behind that of its monochrome ode-ray tube offered the possibility of called his device the "Iconoscope." counterpart. As a result, color- televi- completely electronic image scan- (The Greek word eikon means image sion systems that used some mechan- ning at both the transmitting and re- and skopon means to watch.) He filed ical moving parts continued to be ceiving ends of a television transmis- a patent application on the Ico- investigated. sion. The companion technology noscope in 1923, but legal challenges needed to achieve electronic scan- delayed the granting of the patent First Color -TV Broadcasts. In 1940. ning was lacking, however. Vladimir until late in 1938. Peter Goldmark, President of the Co- Zworykin achieved the first step to- Vladimir Zworykin also had begun lumbia Broadcasting System (CBS). ward that goal while working for the work on developing a cathode -ray demonstrated a color -television sys- Westinghouse Electric & Manufactur- tube suitable for displaying the re- tem based on Farnsworth's "Image ing Company in Pittsburgh in 1923, a ceived television image. His progress Dissector" camera tube. Color was mere four years after immigrating to in that area came more slowly, how- added to that fundamentally mono- the United States from revolution -rav- ever. Zworykin was working for RCA in chrome system by placing rotating aged Russia. 1933 when he developed his first "IG- disks containing red, green, and blue Zworykin realized that a scene to be nescope" (Knema means moving in filters in front of both the camera tube 56 televised had to be broken down into Greek) receiving tube. He used mag- and the receiver picture tube.

www.americanradiohistory.comAmericanRadioHistory.Com The 1200 -rpm rotation of the filter moderately high brilliance levels. The the disk needed for a larger picture disk in front of the camera tube was CBS technique for generating color tube. A 21- inch -diameter picture tube synchronized to the scanning process. television pictures was called the would require a filter disk 5 feet in di- Three fields, formed by using only al- "field- sequential" method because ameter. For a home- receiver picture ternate scanning lines, were scanned the red, green, and blue fields were tube, 30 inches in diameter, the engi- in succession. The first field was scan- produced sequentially. neers showed that a filter disk 8 feet in ned with the red filter in front of the CBS began demonstrations of color diameter, driven by a 5- horsepower camera tube, the second with the television broadcasting using the motor, was required! green filter, and the third with the blue aforementioned system on August 28, An equally important negative fea- filter. The process was then repeated 1940 in New York City. Initially, color ture of those color-television systems to generate three additional fields motion- picture films were broadcast was that they were incompatible with with the scanning lines unused in the but soon after, "live" broadcasts were the industry-wide standards adopted previous field of a given color. made as well. On July 1, 1941, CBS for monochrome television in 1941. The filter disk in front of the picture began a limited daily schedule of The National Television Systems Com- tube rotated in synchronization with color -television broadcasting. During mittee (NTSC), an agency of the Radio that at the camera tube. Con- that same year, RCA rushed to put to- (later Radio and Television) Manufac- sequently, a red field was formed first, gether a similar field -sequential sys- turers Association, had established followed by a green field, then a blue tem of its own design and also began 525 scanning -lines per interlaced field, and so on. Those fields, com- test transmissions using that system. frame, and 30 interlaced -frames per prised of alternate scanning lines, Color television seemed to be off to a second, as the standards. The CBS were effectively combined into 60 good start. color system used 343 scanning -lines fully scanned fields (20 red, 20 green, Several problems existed, however. per interlaced frame and produced and 20 blue) per second by the per - A filter disk 20 inches in diameter was 60 interlaced -frames (20 in each of sistence-of- vision capability of the required for the 9- inch -diameter pic- the primary colors) per second. RCA's human eye and mind. Persistence -of- ture tube Goldmark used in his dem- field sequential system also was in- vision then effectively combined the onstration. In an attempt made after compatible with the monochrome 20 fields in each of the primary colors World War II to demonstrate the im- standards. to produce 20 complete color pic- practicality of rotating disks for color The Second World War brought all tures (or frames) per second. That re- television, engineers at the DuMont commercial television research to a sulted in flicker -free viewing, even at Laboratories constructed a model of halt. During that period, the major re-

PHOSPHOR SCREEN

THREE ELECTRON SHADOW MASK GUNS DEFLECTION YOKE

Fig. 2. The three electron -gun, shadow -mask color -TV picture tube led to RCA's successful development of a compatible color -TV system. 57

www.americanradiohistory.comAmericanRadioHistory.Com ous types continued at both CBS and RCA. CBS began demonstrating a modified field -sequential system that now occupied only a standard 6 -MHz bandwidth. The CBS engineers accomplished that using 405 scanning lines and 144 fields, but could achieve only 77 and 55 percent, respectively, of the vertical and horizontal resolu- tions of standard black- and -white transmissions. Even though the bandwidth of the CBS color system now was the same as monochrome television's, the two systems were not compatible due to the different number of scanning lines and field rates used. By early 1949, RCA was committed to developing a truly compatible, all - electronic, color -television system that occupied the standard monochrome-channel bandwidth of 6 MHz. That reduction in bandwidth was achieved using a "time-division multi- plex" system for transmitting periodic samples of the signals rather than transmitting entire signals. In addition, RCA soon incorporated a technique called "dot interlacing." That permitted increased picture brightness without increased flicker, while still maintaining a 6 -MHz bandwidth. CBS continued to produce color pictures at the receiver through the use of a large filter disk rotating in front of a monochrome kinescope (picture tube). RCA, however, used three sepa- David Sarnoff of RCA led the fight to develop an all electronic and compatible color - rate picture tubes, each one with its TV system. own special phosphors, to produce the red, green, and blue images, research laboratories devoted their viewed in black and white on mono- spectively. The three picture tubes efforts to war -related work. chrome receivers equipped with a were mounted in a single very large UHF -to -VHF frequency converter. Un- cabinet with mirrors to combine the Post -War Developments. In the fall fortunately for RCA, that system could three images into a single picture. of 1946, CBS petitioned the FCC to produce shades of gray and good RCA knew that the large size and approve a field -sequential color -N detail on monochrome receivers only high cost of the three -picture -tube, or system with 144 fields per second and if green subjects were being televised! "triniscope," receiver was not likely to 525 lines per frame as the color- televi- Both the field -sequential and simul- have much appeal to potential sion standard. That required a 12 -MHz taneous color -television systems actu- home viewers. A crash program was bandwidth per channel, twice that ally transmitted three separate pic- initiated to develop a single display used by monochrome broadcasting. tures. As a result, the bandwidths tube that would produce a color pic- The FCC denied the CBS request. required for those transmissions were ture without the use of rotating disks At the same time, RCA was de- inherently greater than that required and other external equipment. David veloping a "simultaneous" color -N by monochrome television. With more Sarnoff made sure that all the re- broadcasting system that required and more television stations being li- sources of RCA were made available four separate transmitters (one for censed all the time, available fre- to that project. each of the primary colors and one quency space was becoming scarce. for the sound) that occupied a total A new color -television system that Standards for Color TV? In Sep- bandwidth of 14 MHz per channel. could operate within the 6 -MHz chan- tember of 1949, the FCC began hear- RCA claimed that its system was nel bandwidths used by mono- ings to determine if industry -wide "compatible" by maintaining that chrome television had to be de- standards now could be established one video signal (the green one) to- veloped. for color television. Testimony began 58 gether with the sound signal could be Color television experiments of vari- immediately, while demonstrations of

www.americanradiohistory.comAmericanRadioHistory.Com the systems being proposed were scheduled to begin later on, in Oc- tober. The testimony and demonstrations would continue off- and -on for many months. The only serious con- testants in that technological competition were CBS and RCA. The RCA system required numerous adjustments to be precisely set in order to have it perform reasonably well. Color instability, a serious problem even under the best of conditions, was aggravated by temperature and humidity effects. The day of RCA's initial demonstration was one of record- breaking heat and humidity. It was in reference to that initial demonstration that David Sarnoff later reported that "The monkeys were green, the bananas were blue " The demonstration of the CBS system went much better. The picture quality was more than acceptable; it was good. However, the hearings were not yet over. Many more months of testimony and demonstrations re- mained. RCA engineers were at work virtually around the clock to improve the design of their system. Noticeable improvements were made prior to the next demonstrations, held in

Further Reading

Abramson, Albert, The History of Television, 1880 -1941,, McFarland & Co. Pub., Jefferson NC, 1987. Barstow, J.M., "The ABC's of Color Vladimir Zworykin, who made many important contributions to the development of all - Television," Proc. IRE, vol. 44, pp. electronic television, is shown :folding his `Iconoscope." (All photographs courtesy of 1574 -1579, November 1955. the David Sarnoff Research Center.) Brown, G.H., and part of which I was -Recollections a Research En- of The Tube. gineer, Angus Cupar Pub., Princeton November. By the end of the Shadow -Mask Picture NJ, 1982. November demonstrations, the most ROAS crash program to produce a Dreher, Carl, Sarnoff-An American serious and obvious remaining draw- single -tube co or display paid off. Success, Quadrangle/The New York back to the RCA system was its need After only approximately four months Times Book Co., New York, 1977. to use three picture tubes in the re- of intensive work, RCA scientists and Harold, Edward W., "History and De- velopment of the Color Picture Tube." ceiver. RCA already could very con- engineers succeeded in producing Proc. Soc. Info. Display, vol. 15/4,pp. vincingly demonstrate the com- prototypes of Iwo versions of what 141 -149, 1974. patibility of its color system with was called a "shadow -mask" picture Ives, H.E., "Television in Colors," Bell existing monochrome television. tube. The company then planned to Lab. Rec., vol. 7, pp.439 -444, July 1929. CBS were busy use both types at the next round of Knapp, J.G. and Tebo, J.D., "The His- engineers also at tory of Television," IEEE Communica- work during that time. They at- demonstrations scheduled for March, tions Society Magazine., vol. 16, pp. tempted to overcome thei- "incom- 1950. 8 -22, May 1978. patibly" problem through the use of a The shadow -mask picture tube Lyons, Eugene, David Sarnoff, converter circuit that could be added used many tiny phosphor clusters, Harper & Row Pub., New York, 1966. Ryder, J.D. and Fink, D.G., Engineers to monochrome television receivers each consisting of three different and Electrons, IEEE Press, New York, built in the future. The question of how light- emitting phosphors arranged in 1984. to enable the millions of already exist- tiny dots on the surface of the viewing Udelson, Joseph H., The Great Tele- ing monochrome sets to receive the screen, One dot in each cluster emit- vision Race, Univ. of Alabama Press, University AL, 1982. CBS color transmissions was left un- ted red light when activated by a answered, however. (Continued on page 94) 59

www.americanradiohistory.comAmericanRadioHistory.Com TRANSMITTER Save time and money with this

PAIR easy -to -use tester that can check 1 the condition of telephone lines, 2 jacks, and more. 3

TELEPHONE TELEPHONE WIRING WIRING TESTER BUILD PHIS TESTER TELEPHONE- WIRING TESTER

As most of you probably know, BY CHRISTOPHER ZGURIS Now, if you look straight into a mod- since deregulation allowed ular jack you will notice tiny bare wires. homeowners and businesses Each tri -color LED contains a red and When the modular plug goes into the to own their own telephone equip- green element wired in parallel. modular jack, the grooves on the ment, phone companies have re- When DC is applied to the LED, it will modular plug guide those little wires sponded by taking no responsibility glow either green or red (depending onto the teeth and contact is made. for any gear, including the wiring, in- on the polarity); if AC is applied, both The 6- position jack is designed to car- side a building unless an extra charge internal elements will glow, resulting in ry up to three voice pairs, depending is paid. As a result, calling the phone an orange color. The Tester can test on the number of contacts. Even company in the event of a service up to four voice pairs at once using though the jack could be a 4- contact outage can be an expensive proposi- one tri -color LED for each voice pair unit, it can only carry two voice pairs if tion. If the problem does not Vie with (each voice pair has two wires that it is hooked up to multi -pair wire. the phone company's equipment carry one telephone line). If the wire going to and from the outside, you can be charged a hefty jack has four conductors (red, green, fee fora service call, and the problem Modular -Jack Basics. Both the yellow, and black) it is a quad cable might still not be resolved. transmitter and receiver each con - and not meant for Iwo voice pairs. If you'd like to avoid that problem, tain three modular jacks: one 6 -posi- That cable is meant for a single voice or if you regularly install or maintain tion, 6- contact jack, and two 8- pair, carried on the red and green telephone equipment, the position, 8- contact jacks. Let's look wires, with the yellow and black ones Telephone - Wiring Tester described in closely at each of those, as well as the carrying power for telephone ac- this article could be for you. The Tester plugs that match them. cessories. If the cable going to and consists of Iwo units, a transmitter and The 6- position, 6- contactjack is sim- from the jack has white -with -blue, a receiver, and is designed to test in- ilar to the jack used for single -line tele- blue -with- white, white -with -orange, stalled telephone wire, modular phones, with one difference: the and orange-with -white wires, it is twist- cords, modular jacks, or any com- single -line version of the jack has 6 ed -pair cable that is designed to car- bination of those for continuity and positions and 4 contacts. Even though ry more than one voice pair. The reversed polarity. the 6- position, 6- contact jacks used in difference between the quad and As we will see later on, the transmit- the Tester units have more contacts twisted -pair cable is that the latter has ter and receiver can be used to- than the ones used for single -line tele- the two voice -pair wires twisted together or individually, depending on phones, they are compatible and the gether throughout the length of the what is being tested. When both units latter can still be tested. If you look at cable, as opposed to the bundled, are used together, the 9 -volt battery in the clear modular plug on the end of individual wires in quad cable. The the transmitter provides power (on a telephone cable, you will notice twisted voice -pairs are highly immune the transmitter's face, there are four from four to six gold "teeth;" those are to crosstalk and noise. standard single -color LEDs that will the contacts. You should also notice If you find a modular plug that has glow when the two units are properly that the "teeth" are set within grooves; eight teeth, then it is not compatible connected to each other). those grooves are the positions. Not with a 6- position jack. Although it looks The receiver uses tri -color LEDs to all the grooves (positions) will neces- similar and works in the same manner, 60 indicate line operation and polarity. sarily have "teeth" (contacts). it is noticeably larger and can only be

www.americanradiohistory.comAmericanRadioHistory.Com R4 PARTS LIST FOR THE B1 22 à 222oS 252 2S20 :11° sl 9V TRANSMITTER T LEDO [ 31 LED3 O LED2 O LED1 - LED1 LED4- Light- emitting diode, //O 1 J. f ***.:42 any color (see text) R1 R4-220 -ohm, 1/4-watt, 5% 2 o resistor 3 o J1, J2 -8- position, 8- contact, 4 modular phone jack O 5 J3- 6- position, 6- contact, modular O phone jack 6 o B1 -9 -volt battery 7 o Perforated board, project enclosure, 8 red and green alligator clips (four of each), battery clip and leads, J2' telephone wire, wire, solder, o hardware, etc. 2 o = 3 O 1 4 o _ 5 o PARTS LIST FOR THE 6 O RECEIVER - 7 O 8 LEDI LED4 -Two -lead, tri -color o light- emitting diode (see text) R1R4-330 -ohm, 1/4-watt, 5% J3' 1 resistor o - J1, J2-8- position, 8- contact, 2 o modular phone jack (see text) 3 o J3-6- position, 6- contact, modular 4 0 phone jack 5 Perforated board, project enclosure, O 6 red and green alligator clips (four n n n RED (;RFFN n of each), telephone wire, wire, solder, hardware, etc. Note: The following is available from RING(-) TIP( +) RING( -) TIP( +), RING( -) TIP( +) RING( -) TIP( +) Christopher Zguris (521 West 26th ` PAIR 4 PAIR 3 PAIR 2 PAIR 1 St. 5th Fl., New York, NY 10001): 'SEE TEXT A partial kit of parts for both Fig. 1. Here is the schematic for the transmitter unit of the Telephone Wiring Tester. Tester units containing all LEDs, The alligator clips shown at the bottom of the diagram can be used to connect the resistors, modular jacks, alligator transmitter to the receiver or to telephone -line voice pairs. Of course, telephone lines clips, and four-conductor wire: can also be connected to modular jacks JI J3. $23.00 + $4.00 S /H. New York residents please add appropriate sales tax. used with an 8- position, 8- contact connected to a closed circuit (that modular jack. could be the receiver unit, a tele- The two 8- position, 8- contact jacks phone line, etc). When all the lines in each unit are wired differently. One (pairs) of the circuit are closed, power When the receiver (see Fig. 2) is atis wired as a USOC (Universal Service from the 9 -volt battery, 81, flows tached to the transmitter (using the Order Code) jack (usually used to car- through the 220 -ohm current -limiting modular jacks or the alligator clips), ry four telephone lines) and the other resistors, R1 -R4, to the single -color power flows through the 330 -ohm is wired for the AT&T standard (used for LEDs, LEDI -LED4, causing them to current -limiting resistors, R1 -R4, to the the Merlin and other key systems). The light. If only some of the line pairs ore tri -color LEDs, LEDI -LED4, If power 6- position, 6- conductor jack in each connected to closed circuits, then comes through the modular jack con- unit is wired to the USOC standard, only the LEDs in series with those lines tacts or alligator clips with the correct which is what most standard tele- light up (LEDI connects to pair 1, LED2 polarity, the tri -color LEDs on those phone devices use. connects to pair 2, etc.). lines will glow green. When power Power from the transmitter goes out comes in reversed, the tri -color LEDs in Finally, if How it Works. Figure 1 shows the the positive contacts on the modular the proper lines will glow red. schematic of the Tester transmitter. No jacks or green alligator clips. The there is a short, the LEDs in the trans- power switch is used in the unit; the negative contacts and red alligator mitter will glow because the short has circuit is turned on either when the clips are attached to ground (the completed the circuit, and the tri- clips in pairs 1-4 or jacks J1 -J3 are negative terminal of B1). color LEDs in the receiver w11 not glow. 61

www.americanradiohistory.comAmericanRadioHistory.Com Jacks J1 -J3 in the transmitter (Fig. 1) PAIR 4 PAIR 3 PAIR 2 PAIR 1 are exact matches for jacks J1 -J3 in RING( -) TIP(+) RING(-) TIP( +) RING(-) TIP( +) ' RING( -) TIP( +) the receiver (Fig. 2), and are wired in the same way. Modular-jack J1 is a 8- position, 8- contact unit that is wired as RED GREEN a USOC jack. Jack J2 is also an 8- LEDI RED R1 position, 8- contact unit, but is wired for 33oú the AT &T standard. Finally, jack J3 is a 6- position, 6- contact unit, that is also wired as a USOC jack. J1' Construction. The author's prototype units were built on perforated board using point -to -point wiring, but any standard project -building method can be used. Just make sure that the correct wires are connected to the correct LEDs. To make things easier, use multicolored connection wires to connect each point on the modular jacks to the correct component or common point. The project enclosures used for the prototype units are the transmitter cases available from Radio Shack (catalog no. 270 -293); they have built - in 9 -volt battery compartments with slide -off covers. You will probably have to cutthe circuit boards to make them fit into the cases. For that reason, make sure to keep the circuit connections close together; the wiring can get a bit cramped, but if you are careful you should have no problems. You will also have to cut holes in the cases *SEE TEXT for the LEDs. Make sure to label those holes with the matching pair number 5 o (LEDI in both units should be labeled "Pair 1," LED2 is "Pair 2," etc.). The tri -color LEDs used in the re- Fig. 2. The receiver circuit shown here contains tri -color LEDs to let the user ceiver have to be of the type with only determine whether polarity on a phone line is correct (a green glow) or reversed (a red two leads; the ones used in the pro- glow). Also, it indicates if AC is on the line (an orange glow). totype are available from Radio Shack (catalog no. 276 -012). Three - semblies for the pairs of alligator clips. bers on it. If you use the colored tape, lead tri -color LEDs are available, but To do that, take eight short lengths of the colors should be blue for pair 1, they will not work in the receiver cir- 4- conductor, 22- gauge, solid- copper orange for pair 2, green for pair 3, and cuit. If you cannot find Iwo-lead tri- station wire, strip off the ends of the brown for pair 4. Those colors corre- color LEDs you can get the same result outer sheaths, and clip the protruding spond with the standard color order by taking a red LED and a green LED yellow and black wires at both ends. for twisted -pair cable. and wiring them together in parallel Then solder one red and one green When you have completed all the with their polarities crossed (anode - alligator clip to the remaining red and electrical connections in the circuits, it to- cathode, cathode -to- anode), or green leads on one end. Repeat that is time to attach the modular jacks to you can order the LEDs as part of the for the other seven cables. When each other, side by side, using a few partial kit available from the source that's completed, solder the red and drops of epoxy. Then take those three - given in the Transmitter Parts List. Tri- green leads at the other end of the jack assemblies and attach to them color LEDs must be installed correctly cable pairs to the correct points in the to their respective project cases using to get the color results mentioned in circuit. epoxy. After the epoxy dries, use a few the tests. In the Radio Shack LEDs that Each cable pair should be num- more drops of epoxy to glue the wire were mentioned earlier in this article, bered to correspond with the voice assemblies to the cases. Once the ep- the flat pin should be connected to pair it is connected to. To accomplish oxy dries the whole assembly should the negative line. that, you could use colored wire - be very strong. 62 The next step is to create wire as- marking tape and write the pair num- (Continued on page 94)

www.americanradiohistory.comAmericanRadioHistory.Com Azero -center DC voltmeter, cilloscope, external voltmeter, or also an output indicator. That device is often called a galvanometer, other display device). a zero- center milliammeter with a is a useful addition to any The voltage gain (A) of the Gal- range of -1 to + 1 mA. Because the hobbyist's workbench. That's because viamp is a function of the resistance output signal at pin 1 of U2 -a is a volt- many circuits, including the Wheat- between the inverting outputs of U1 -a age, and the meter is a current meter, stone bridge, need to be used with (pin 2) and U1 -b (pin 6). That function it is necessary to convert M1 into a that type of null indicator. Also, an- can be solved for using the formula: voltmeter. That is accomplished by re- other handy device to have around is sistor R13, which is connected in series R = 112,000/( - 1) a variable -gain amplifier that can be with the meter. The value shown for used with an external device, such as where R is the resistance in ohms be- R13 is probably suitable for most com- an oscilloscope. Of course, purchas- tween the two inverting outputs. In the mon milliammeters, but there is a pos- ing both of those devices could be Galviamp, that resistance value is se- sibility that it will have to be replaced expensive. lected by a double -pole triple -throw for certain meters (more on that later). So, do you want an inexpensive way (DP3T) switch, S1. That switch selects a The value of R13 is set to produce a 1- to get both units? Build the Galviamp 220 -ohm resistance in the HIGH mAcurrent in M1 when the outputvolt- described in this article. The project is position, a 2200 -ohm resistance in the age of U2 -a is at its maximum per- a combination of a gal- missible value. Because 9- vanometer and a variable - volt batteries are used for the gain amplifier in the same power supply in the Gal- package. And best of all, the viamp, the maximum output Build voltage will be around 8.5 sacrifice the Galviamp doesn't performance for com- volts. pactness. The third output indicator for the Galviamp is made up Circuit Description. Figure of LEDI and LED2. Because - 1 shows the schematic for they are connected "back the Galviamp. Op -amps Uf- to- back," the LEDs become a, U1 -b, and U2 -a form a dif- forward biased with op- ferential amplifier with a very posite polarities. In other high input impedance, while words, when a positive volt- U2 -b is used as a driver for a age is applied to the point pair of back -to -back LEDs where pins 6 and 7 of U2 -b (LEDI and LED2) that help are connected, LED2 emits find the null condition. Both light and LEDI remains off. U1 and U2 are CA3240 "Galviam " But when the voltage is p LED2 off BiMOS dual op -amps, avail- negative, remains able from Digi -Key (IO. Box BY JOSEPH J. CARR and LEDI lights. Resistors R11 677, Thief River Falls, MN, and R12 limit the current to 56701 -0677; Tel. protect the LEDs. It's two handy devices -a galvanometer The LEDs are driven from 1- 800 - 344 -4539), as well as other sources. and variable -gain amplifier - the output of U2 -b. That op- A differential -input ampli- amp is connected in the uni- fier is formed by U1 -a and U1- in one compact case. ty -gain, noninverting-fol - b. Each of those op -amps is lower configuration, which is connected in a noninvert- when the output (pin 7) is ing- follower configuration. That con- Low position, and a variable resistance connected to the inverting input (pin figuration is used because the input of 150 to 1150 ohms in the VARIABLE 6). The voltage gain is + 1, so the volt- impedance of the overall amplifier is position. The HIGH and Low positions age where pins 6 and 7 meet is equal essentially the input impedance of produce fixed gains of about 500 and to the output of U2 -a. the device (which is not true if the 50, respectively, and the VARIABLE The DC power for the Galviamp is inverting follower circuit is used). For a position results in a variable gain of 96 supplied from a pair of 9 -volt bat- BiMOS op -amp, the input impedance to 745 (depending upon the adjust- teries. The op -amps require two is approximately 1012 ohms! ment of R4). power supplies because their outputs Op -amp U2 -a is configured as a There are three output indicators might have to swing either positive or DC- differential -amplifier circuit that used on the Galviamp. First, there is negative, depending on the input sig- combines the outputs of U1 -a and U1- the analog- output jack, J4, which can nals and their polarities. Battery B1 b. The output of U2 -a is equal to the be used to drive any of several display supplies a negative power source difference between the outputs of U1- or recording devices (for example, an with respect to ground or common, b and U1 -a. That output voltage is ap- external voltmeter, an oscilloscope, or while battery B2 supplies a positive plied to both meter M1 and output - the analog -to- digital- converter input source with respect to ground or com- jack J4 (which can be used to send of a computer). mon. Those power -supplies are .the analog output signal to an os- Second, the built-in meter, Ml, is switched on and off by switch S4, a 63

www.americanradiohistory.comAmericanRadioHistory.Com R17 10K ZERO R11 CONTROL 3300 R15 10K 12CA3240

R14 -IN 8 100K R16 + J1 o C3 - 10K R4 U1-a 1 R12 2 1K 3300 VARIABLE R3 '12CA3240 J4 GAIN ADJ 1500 VARIABLE R7 ANALOG 4l144- O LOW Sl-a 10K OUTPUT

HIGH I R5 'Oh 1 /%1 LED2 COM R1 56K R2 I GAIN O LED1 J3 2.2K 2200 I d 01 R6 R8 i 56K 10K 3 I S1-b

O S4-a R9 --0 6 5.6K R13`S 1 7 6.8K 7' I POWER +IN J2 R10 S4bi 4 --040.0-1 10K M1' CMRR ADJ B1 B2

1 9V 11 I 9V = C4 'SEE TEXT C2.1 .1

Fig. I. Here's the schematic for the Galviamp. Notice that batteries BI and B2 are configured to provide either positive or negative power to UI and U2; those op -amps require two power supplies because their outputs might have to swing either positive or negative, depending on the input signals and their polarities.

double -pole single -throw (DPST) tog- of which are referenced to ground) the Galviamp operates as a one -in- gle switch. and the amplifier responds to the dif- put inverting amplifier. Third, when S2 Note that a 0.1 -µF capacitor is conference between the signal voltages is closed and S3 is open, the J1 input is nected between the power -supply applied to each. The +IN input, J2, is grounded, and the circuit operates as pins of both op -amps and ground. "noninverting" (that is what is indicat- a noninverting amplifier. Fourth, if S2 Those capacitors are needed to pre- ed by the " +" sign) so it produces an and S3 are both open, the circuit goes vent the op -amps from bursting into output that is in -phase with the output. into a differential mode. self -oscillation -an undesirable prob- In other words, a positive signal at J2 lem. Those capacitors must be will produce a positive -polarity output Construction. In the author's pro- mounted as close to the power -sup- signal at J4 and M1; similarly, a nega- totype, the amplifier electronics were ply pins (pins 4 and 8) of each op- tive input on J2 places a negative sig- built on a perforated board with a amp as possible, and the leads must nal at J4 and M1. ground bus, using point to point wir- be kept as short as possible. The -IN input, J1, is inverting (as indi- ing, but any other project-building Potentiometer R17, the zero control, cated by the " " sign), so it produces technique can be used. The intercon- is essentially an offset null control. It is an output signal that is 180 -degrees nections on the board can be made adjusted to force the output voltage out -of -phase with the input signal. with 24 -gauge solid hook -up wire. As of U2 -a to zero when the input voltage That is, a positive signal applied to J1 with most projects, install the ICs last, is zero. That is done with both inputs, J1 produces a negative signal at J4 and to prevent them from being and J2, shorted to the common termi- M1, while a negative signal at J1 pro- damaged. Several components nal, J3 (more on that later). The CMMR duces a positive signal at J4 and M1. mount off -board, on the front panel of (common -mode rejection- ratio) ad- Switches S2 and S3 can be used to the project enclosure. Those are: just control, potentiometer R10, is used set the circuit to four operating J1 J4, S1 -54, R4, R17, LEDI and LED2, to balance the amplifier to make it modes: First, when both S2 and S3 are and M1. truly differential (a differential ampli- closed, both inputs (J1 and J2) are Before mounting milliammeter M1, fier does not respond - to common shorted to ground; that mode can be make sure that you have a proper- mode signals -signals that are ap- used for testing, and for ensuring the value resistor for R13. If you find that a plied equally to inputs). both zero -volts baseline is, indeed, zero value other than 6800 ohms is The Galviamp uses a differential in- volts. Second, if S2 is open and S3 is needed, try this method to find a suit- 64 put. That is, there are two inputs (each closed the input of J2 is grounded, so able substitution: To begin, determine

www.americanradiohistory.comAmericanRadioHistory.Com the value of your meter's resistance. pare their light output. Try several, and You might find that number inscribed use the pair that seem to match the in nearly imperceptible type in a best. lower corner of the meter face. Other- The project enclosure used in the wise, you might have to consult the author's prototype is the Radio Shack manufacturer's catalog or data sheet. A "Experimenter's Box" (270- 627) -it is In a pinch, you can measure it with an made of plastic, and has an alumi- ohmmeter, but that might be dan- num front panel (if the Galviamp is to gerous to the milliammeter. be used in the presence of strong RF If you use an analog ohmmete to fields, then an all- aluminum cabinet measure the resistance, then make can be substituted to provide shield- sure that it doesn't use an internai bat- ing). Insulated 24 -gauge hook -up tery with a value of more than 1.5 volts. wire can be used for connecting the Some older -model vacuum -tube volt- panel- mounted components to the meters used a 22.5 -volt battery, and remainder of the circuit. However, you those are guaranteed to wipe out a might want to use wires of different milliammeter being tested. Your best colors to spare yourself some eye bet is to use a digital multimeter on strain. the low- powered ohmmeter setting. vOD When you are done wiring all the Be careful not to use the "diode" set- on- and off -board components to- B ting, however, as that will probably gether, carefully go over all your con- damage the milliammeter as welll. Fig. 2. A simple resistor voltage-divider nections a second time. Make sure in Whichever ohmmeter you use, start network (A) is one half of a Wheatstone - particular that the ICs are hooked up bridge circuit (B). correctly. PARTS LIST FOR THE GALVIAMP at the highest ohms scale and con- Adjustment and Setup. Adjusting nect one lead of the ohmmeter to the the Galviamp is relatively simple, es- RESISTORS milliammeter. Then quickly and lightly pecially if you have an oscilloscope or (All fixed resistors are 1/4-watt, 5% tap the other lead to the other milli- AC voltmeter available to use as an units, except where noted) ammeter terminal while watching AC output indicator. To begin, turn on R1 -2200-ohm that meter's pointer. If that pointer switch S4 and note the indication on R2 -ohm -220 doesn't deflect rapidly, then it's proba- Ml. If M1 slams to one peg, R3- 150 -ohm bly safe to continue. If it does move immediatelyturn off S4 and look for a R4- 1000 -ohm, linear-taper the wiring error. But if M1 is either at zero, or potentiometer rapidly to one end, then lower moderate positive or negative RS> R6- 56,000-ohm ohmmeter scale and try again until some R7, R8, R15, R16- 10,000 -ohm you don't get a deflection. deflection, then proceed with adjust- R9-5600 -ohm Once you know the value of the ment after letting the unit warm up for RIO, R17- 10,000-ohm, linear -taper meter's resistance (Rm), then the value about 5 minutes (to control drift). potentiometer of R13 (in ohms) can be calculated Next, short J1, J2, and J3 together by R11, R12- 330 -ohm, Y2-watt from: closing switches S2 and S3. Turn R10 R13---6800 -ohm (see text) approximately to the middle of its R14-100 ,000-ohm R13 = 1000Vmax Rm - range, and set S1 to the Low position. ADDITIONAL PARTS AND where Vmax is the maximum output Adjust R17 (zero control) for a zero -mA MATERIALS voltage at pin 1 of U2 -a (that should indication on Ml. Then set S1 to the Ul, U2-CA3240 BiMOS dual op be approximately 8.5 volts). HIGH position, and re- adjust R17. Con- amp, integrated circuit Once the value of R13 is deter- nect either an AC voltmeter or an os- light -emitting LEDI, LED2-Red mined, select an actual resistor that is cilloscope to analog- output -jack J4. diode (see text) of the next- higher standard value. Al- Open switches S2 and S3, and con- CI-C4 ß.i -µE Mylar capacitor ternatively, make a series combina- nect a short piece of uninsulated wire MI -Zero- center milliammeter (see text) tion of a potentiometer and a fixed from J2 to J3. Connect an audio -sig- Si--DP3T rotary switch resistor; adjust the potentiometer so nal generator to that wire (use 100 to S2, S3-SPST miniature toggle that the combination equals the cal- 2000 Hz if an oscilloscope or AC volt- switch culated required resistance value. meter is used at J4, or 100 to 400 Hz if S4-DPST miniature toggle switch There are Iwo other components the "AC" function of an ordinary multi - 31-13- Binding post that need to be selected carefully for meter is used). Adjust the signal gener- J4--Phono jack, chassis -mounted use in the circuit: LEDI and LED2. They ator output to about 1- to 3 -volts peak - BI, B2 -9 -volt battery are connected in a back -to -back to -peak. Perforated board, project enclosure configuration, and to work properly, Set S1 to the Low position again, and (Radio Shack 270 -627 or the LEDs should be uniform in output adjust R10 for minimum AC- signal out- equivalent), two battery clips, two light levels. To test LEDs for that, con- put. Set switch S1 to the HIGH position 8 -pin IC sockets for Ul and U2, wire, solder, hardware, etc. nect them in series with 470 -ohm re- and adjust R10 again until no further sistors to 9 -volt batteries and corn- improvement is possible. Disconnect 65

www.americanradiohistory.comAmericanRadioHistory.Com the audio -signal generator and re- family of medical, engineering, and move the short from between J2 and scientific instruments. J3. The Galviamp is now ready for use. The photoresistors can be any two As a matter of practice, keep S2 and matching units. Once you have se- S3 closed when the amplifier is not lected two identical ones, use an being used. ohmmeter to measure their nominal resistance at normal room- illumina- Wheatstone Application. The Gal- tion levels (be sure that the resistance viamp Fig. 3. Simply connect the V output of can be used for a wide variety , is not less than about 500 ohms, or a Wheatstone bridge to the -IN and +IN of workbench and experimenter ap- battery life will be short, and the pho- inputs of the Galviamp to use the two plications, but it also has its applica- toresistors circuits together. might self -heat, causing er- tions in scientific instrumentation. One rors). Select fixed resistors for R1 and R3 such application is to use the Gal- R5' that have approximately the same re- viamp as an amplifier for a Wheat- sistance value as the photoresistors. stone bridge. The value of R5 should be from 0.381 A Wheatstone bridge can be de- to 1.581 to make it easy to balance the veloped from a simple resistor volt- bridge. age-divider network, shown in Fig. 2A. Build the circuit on a piece of perf- Output -voltage Vo is a fraction of ap- board, keeping photoresistors R2 and plied- voltage V. The value of Vo is R4 about 2 to 3 inches apart. If the found from: photoresistors have clear edges, Vo = VR2 /(R1 + R2) cover the perimeter with black tape or black paint to prevent scattered In the context of the Wheatstone VOD light from entering. Make sure that bridge, Fig. 2A is sometimes called a (TO GALVIAMP) light only enters through the front of half- bridge circuit. If R2 is either a ther- Fig. 4. By using two photoresistors in a the lens over the active region. mistor or a photoresistor, then the out- Wheatstone bridge, and adding a Connect the output of the color- put voltage will be proportional to potentiometer, you can make a imeter (Vod) to the input of the Gal- either the temperature light colorimeter for use with the Galviamp. or level, viamp, and then expose the pho- respectively. A disadvantage of that toresistors to room light so they are circuit is that there is a perpetual DC Suppose R2 is a potentiometer, and equally illuminated (with no shadows). offset unless R2 has a value of zero R4 is a temperature sensor. Calibrate Adjust R5 for a null condition on the ohms. If we have a temperature a dial connected to the shaft R2 in of Galviamp meter. By interposing col- probe at R2, therefore, a zero -degree units of temperature, using the ored filters between the light source temperature does not yield a zero - characteristics of the thermistor used and one (only one) photoresistor, it is volt output state. That problem can be for R4 to determine If the range. you possible to get a rough idea of the solved by the Wheatstone bridge cir- allow the thermistor to stabilize, and percentage of the white light that the cuit shown in Fig. 2B. then adjust R2 for a null condition on color represents. Just consider the If we connect two half bridges in Ml, the temperature can be read one -milliampere range of M1 to be a parallel, in Fig. 2B, as we have the from the dial attached to R2. 100 -percent range. classic Wheatstone bridge circuit; R1 When designing Wheatstone (Note: The response of a pho- and R2 form one half of the bridge, bridge circuits for an experiment, re- toresistor is not consistent across the while R3 and R4 form the other. The member this: The ratio of the Iwo half entire visible -light spectrum, so any differential output voltage is the bridges must Vod be equal for a null to percentages derived with the color- difference between the output volt- occur, but the actual resistance val- imeter are approximate only.) ages of the two half bridges, and can ues can be different. That is: One use for the colorimeter in sci- be calculated using: ence is to measure the absorption of R1 /R2 = R3 /R4 R2 R4 certain wavelengths of light or in- Vod = Figure 3 shows how to V Rl + R2 R3 + R4 connect the frared (with different sensors) of a Wheatstone bridge to the Galviamp. sample. In one measure of blood -oxy- When the two half bridges are in The output voltage Vod is connected gen level (p02), for example, a stan- balance, the output voltage is zero. In across the differential inputs ( -IN dard- wavelength red filter is placed that state, the bridge is said to be in a to +IN) of the Galviamp. The output in front of one photoresistor, and a null condition. If the values of resistors voltage Vo is equal to the product of calibrated volume of blood is placed R1 through R4 are correctly selected, the differential gain of the Galviamp in front of the other. The unbalance of then the null condition can exist when and the bridge output voltage (Vod). the bridge is proportional to the oxy- the physical parameter (e.g. temper- gen saturation of the blood sample. ature) is also zero. Exact values of the A Colorimeter. Figure 4 shows an Although blood analyzers are now applied parameter can be read as application for the Galviamp that complex instruments driven by com- deviations of Vod from zero. uses two photoresistors, R2 and R4. puters, early models (some still used) The Wheatstone bridge can also be That little circuit is called a color- are little more than expensive, preci- 66 used for comparison measurements. imeter, and is the basis for a large sion versions of Fig. 4!

www.americanradiohistory.comAmericanRadioHistory.Com 1990 was a Great Year for Popular Electronics The twelve 1990 issues PAST of Popular Electronics TOPICS FROM THE reveal many fascinating ar- Selected Projects External Drive for Laptop, June Aud o Ambiance Ditherizer, April First Electric Motor Project, October ticles. There's a bonanza of Bit Grabber for Parallel I/O Testing, December Ground Fault Technology, November build -it project plans, infor- Car -Radio Silencer, October Keeping Up with Pacemakers, July mative theory articles and Cordless Test Probes, January Living with Lightning, October Receiver, May Make Your Own Iron -on PC Patterns, July stories. CW and SSB, Add to a SW timeless feature Digital Entry Switch, November Old -time Radio Circuits, March Check out the partial list of Economy Portable SW Receiver, August Oliver Lodge: Radio's Forgotten Pioneer, July April titles packed into the 1990 Exhaust Monitor for Car, June Restoring a Classic SW Receiver, Experimental AC Hum Sniffer, September Solar Power, Experimenting with, June. issues and you'll agree that Game Reaction Timer, April St. Elmo's Fire, September 1990 was a banner year. If Headphone Output for Your CD Player, July Surface Mount Technology, November Television Night, a Look Back. July you see an article about a Hot -Wire Glass Bottle Cutter, December Alarm, December Tune -in to Satellite Radio, May project, theory topic or Indoor Burglar IR- Triggered Sound -Effects Generator, October Using Appliances Overseas, January newsworthy feature, you can Lie Detector, Simple, January Theory for Everyone Microphone Preamp, Simplest, March have that article, with the en- 3- Terminal Voltage Regulators. May Mobile Battery Charger, March tire issue for only $6.50. To 200,000 -volt van de Graaff Generator, October NiCd Battery Tester, August All About Batteries, August 1990 issue(s) of Display, Custom, February get your Plasma All About Thermistors. December Receiver Circuits You Can Build, March Popular Electronics, place CCTV Installation Guide, November FAX Switch, August Remote -Control Connect Anything to Your Computer, August a the box that indicates /in Cable Tester, January Serial Designing Power -supply Circuits, February want and Toll Totalizer, August the month you Telephone Digital Electronics Introduction, April Tesla's Lightning Generators, September complete the coupon below. Experiments in Electrophotography, March The Lepton Candle, October six or Fiber -Optic Communications, April Note that ordering Morse -Code Transceivers, July Ultrasonic Galvanometer, Build and Learn, September reduces the 3- Terminal Power Supply, November more copies Universal Lasers, All About, September Titler, Super Simple, September price per issue! Tear out this Video Printer Technology, October Vision System for Robotic Toys, March November make a photo copy Signal Generator Circuits Cookbook, page, or and Transmitter, July VLF Receiver Stepping Motors Introduction, March or FAX it Leak Alarm. January of it, and mail Water Troubleshooting Computer Disk Drives. May today! Just follow the direc- Special Features Troubleshooting Your Printer, December tions below. Antenna Installation, September Typing Practice Program, August Capacitors, Choosing and Using, June Sideband Amplifiers, January Classic Amateur Receivers, November Wimshurst Machine, December Drying Out Flood- Damaged Equipment, January WW1 Long Island Spy Station, December Popular Electronics Early Radio Transmitters, May 1990 Issues

January February March April May June July August Sept. Oct. Nov. Dec.

Check the issue(s) you want. Visa MasterCard USA Bank Check US or Internnational Money Order How to Determine Cost per Copy Exp. Date / Price per copy Credit Card Number (If used) Quantity United States Canada Foreign Signature Total No. of Copies 1 -5 $6.75 US $7.75 US Print Name Total Amount $ 6 -12 5.75 6.75 $8.50 US Address Prices include handling and shipping costs. Prices subject to change. All Canada and foreign orders payable in U.S.A. City State ZIP funds only, via international money order, check drawn on a U.S. bank, or acceptable credit card (Visa, MasterCard) in P.O. Box 4099, Farmingdale, NY 11735. No COD orders. U.S.A. funds. Allow 6-8 weeks delivery. Minimum foreign Send orders to: CLAGGK, Inc. or FAX 516 -293 -3115. 67 order --6 issues. Foreign orders may take longer. Credit Card user may telephone or FAX order. Telephone 516-293-3751

www.americanradiohistory.comAmericanRadioHistory.Com ANTIQUE RADIO

By Marc Ellis As those who have been Later on in the session, I outside of the winding to following this column treated all of the controls further protect the leads for the past few months with a control cleaner /lubri- and give the repair a more know, we're in the process cant and spent some time finished appearance. The of restoring a Minerva Trop - on the damaged filter winding was then slipped icmaster Model W-117. Not choke, which had been dis- back on the choke's "E "- much is known about the mantled for inspection and shaped iron core, and the history of either the set or its repair in the last session. iron pole -piece was laid Putting manufacturer, but the ra- Both choke leads had be- across the open end of the dio's high -performance come disconnected from "E." After returning a fiber circuitry, Minerva battleship con- the winding inside. They spacer/shim to its place on Back struction, and just -post -WWII were successfully recon- top of the pole piece, the Together release date war strongly nected, then secured in choke's metal frame could suggest that it is really a place on the surface of the be slid over this assembly to surplus military morale ra- winding with a couple of hold everything together. dio in civilian dress. globs of epoxy cement. The metal tabs that lock- Finally, the tuning capaci- ed the coil /core assembly tor frame, which someone into the frame had been had dismounted from the removed during a previous chassis (it was held in place disassembly, but that didn't only by its wiring), was snug- matter. Once the choke ged down against its was reinstalled, the open rubber -grommet shock ab- end of the frame would be sorbers with a new set of pressed tightly against the screws, nuts, and washers. chassis, locking all parts to-

gether. I now fed the REINSTALLING THE chokes new leads down CHOKE through the grommeted

I had gotten a lot of "pass-though" hole pro- satisfaction out of replacing vided for them and the Tropicmaster's dingy refastened the frame to the and mold- covered paper chassis. It certainly felt good and electrolytic capacitors to have the unit's leads, coil, with a new set of depend- core, and other parts se- The early stage of the reassembly process. The filter choke able, modern units. But I curely reunited once and (behind the forward IF transformer) and the dial plate are in was no less pleased to be for all! place; the speaker is mounted on the front panel. putting the filter choke back together at last. Dig- SPEAKER AND DIAL At the start of last month's ging out the ends of the REASSEMBLY session the set was already winding from the sticky Next, I took a look at the partly dismantled to facili- layers of electrical and speaker, which those who tate the restoration work, Scotch tape that had tem- have been following the and the top surfaces of the porarily secured the leads story from the beginning chassis were given a care- to the choke core had know was covered by a ful cleaning with Brasso, been a an annoying experi- coating of fine rust. I had relatively non -abrasive met- ence, but it felt good to originally intended to clean al polish. The radio was also have successfully recon- up the rust a bit and try to completely recapped, a nected a new set and duplicate the original finish procedure deemed neces- securely anchored them so of the speaker frame with sary because of its that they would not pull coat of aluminum paint. But obviously long residence in loose again. now I reexamined this plan a damp environment (very Now that the epoxy "an- and decided not to go destructive to the wax -cov- chors" had completely set, I through with it. ered paper capacitors carefully taped a layer of The chassis itself had not 68 found in sets of that era). black duct tape around the come out exactly pristine-

www.americanradiohistory.comAmericanRadioHistory.Com Just like these Graduate with an Associate Fully Trained Electronics Degree from CIE! Professionals CIE is the best educational career skills. Each lesson is value you can receive if you designed to take you step - want to learn about by -step and principle -by- electronics, and earn a good principle. And while all of electronics. And every CIE income with that knowledge. CIE's lessons are designed Course earns credit towards CIE's reputation as the world for independent study, CIE's the completion of your leader in home study instructors are personally "Thanks to CIE I have tripled my previous Associate in Applied Science electronics is based solely available to assist you with salary, and 1 am now in a challenging and Degree. So you can work rewarding new field where only the sky is on the success of our just a toll free call. The result toward your degree in stages the limit." graduates. And we've is practical training... the kind Daniel Wade Reynolds or as fast as you wish. In fact, earned our reputation with of experience you can put to Industrial Electrician CIE is the only school that an unconditional commit- work in today's marketplace. Ore -Ida Foods actually rewards you for fast ment to provide our students study, which can save you with the very best electronics LEARN BY DOING...WITH money. training. STATE -OF- THE -ART 91T ED Just ask any of the EQUIPMENT AND 150,000 -plus graduates of TRAINING. the Cleveland Institute of CIE pioneered the Electronics who are working first Electronics in high -paying positions with Laboratory 'CIE was recommended to me by my boss. aerospace, computer, It was appealing since I could study at my own pace at home and during business medical, automotive and ravel." communications firms Dan Parks throughout the world. Manager/Consumer Products Marketing They'll tell you success Analog Devices, Inc. didn't come easy...but it did come... thanks to their CIE training. And today, a career in electronics offers

more rewards than ever . before.

" loved the flexiblity CIE offered. It was the CIE'S COMMITTED TO Course only way I could continue both school and BEING THE BEST...IN ONE and the first my demanding job." AREA...ELECTRONICS. Microprocessor Britt A. Hanks no Director of Engineering CIE isn't another be- Course. Today, Petroleum Helicopters, Inc. everything-to-everyone other home study school. CIE teaches only school can match CIE's one subject and we believe state -of- the -art equipment we're the best at what we and training. And all your do. Also, CIE is accredited laboratory equipment, books by the National Home Study and lessons are included in YES! I want to get started. Council. And with more than your tuition. It's all yours to Send me my CIE course catalog including details about the 1,000 each year, use while you study and for graduates Associate Degree Program. (For "I liked the way the school was set up with on- the -job after you we're the largest home study your convenience, CIE will have a laboratory assignments to enforce graduate. conceptual learning. The thing which school specializing exclu- representative contact you - there impressed me the most about CIE's sively in electronics. CIE has is no obligation.) curriculum is the way they show application been training career -minded PERSONALIZED Please Print Clearly for all the theory that is presented" students for nearly sixty TRAINING....TO MATCH Daniel N. Parkman Name Missile Electro- Mechanical Technician years and we're the best at YOUR BACKGROUND. U.S. Air Force our subject... While some of our students ELECTRONICS... have a working knowledge of Address electronics others are just IT'S THE ONLY SUBJECT City WE TEACH! starting out. That's why CIE has developed twelve career State Zip Age CIE PROVIDES A courses and an A.A.S. LEARNING METHOD SO Degree program to choose Phone No GOOD IT'S PATENTED. from. So, even if you're not Check boa for G.I. Bill Benefits. 'Completing the course gave me the ability CIE's AUTO -PRO- sure which electronics career Veteran troubleshoot modern o efficiently a is best for you, CIE can get Active Duty AH67 microprocessor based audio and video GRAMMEDO lessons are proven learning method for you started with core lessons ystems and enjoy a sense of job security." Cleveland institute of Electronics, Inc. Tony Reynolds building valuable electronics applicable to all areas in 1776 East 17th Street Service Manager/Technician Cleveland, OH 44114 Threshold Audio & Video Send for CIE's FREE Course Catalog and A School of Thousands. LA Class of One. Since 1934. See How We Can Help Your Career Too!

www.americanradiohistory.comAmericanRadioHistory.Com looking after cleaning. The complete the panel -and- SMOKE TEST TIME Tropicmaster does not have

grime was gone, but there radio sandwich-locking Now all I had to do be- a built -in loop antenna, I were plenty of dark and everything together in a fore it would be possible to moved the set into my ra-

pitted spots where moisture rigid assembly. try the set out was to re- dio shack, where I could had attacked the anodized Once mounted between install the tubes. They had hook it up to the long -wire finish. A completely re- the panels, the radio chas- been tested when the set ham antenna.

finished speaker frame sis is suspended about a was originally dismantled, However, I decided to would look quite out of half -inch above their bot- and (although some of the check for signs of life before place, and I'm not sure how tom edges so that -after metal tubes had suffered actually connecting the set well the aluminum paint the set is mounted in its from corrosion) all except to the skywire. Since all of would have matched the metal cabinet -the chassis the 25Z6 rectifier had tested the capacitors were new, frame's original paint (or can't come in contact with good. The latter was dead there was no need bring anodizing) anyway. the cabinet floor. All of that as a doornail, probably a the line voltage up slowly

Using a fine emery cloth went together quite casualty of the same short- during start -up. I just flicked (I had to stay away from on the power switch, steel wool because of the whereupon the room was danger of fouling the bathed in white light from speaker's permanent mag- the biggest dial -light flare -

net with metal dust), I up I had ever seen! I don't cleaned off as much rust as know why the bulb didn't

I could. That resulted in a burn out before it dimmed speaker that was definitely down to its normal operat- better looking and quite ing level. consistent in appearance Making a mental note to with the rest of the chassis. investigate the pilot -light sit-

The speaker was now uation later, I continued to mounted on the front panel observe the set as it warm- and that assembly was set ed up. No plumes of smoke

aside while I turned my at- drifted out of the chassis, tention to replacing the dial but-even after several

cord. That is something I do seconds -there was no

with every set I restore sound from the speaker. It whether it needs it at the Here's the Tropicmaster chassis completely reassembled, re- was beginning to look as if time or not. I've had too tubed, and ready to try out. more troubleshooting many old cords break after would be necessary before

a set was reassembled and smoothly, although I had to ed capacitor that caused I could have an operating put back into use! stop and backtrack a bit the demise of the filter set.

The Tropicmaster's dial - when I realized I had for- choke. As sometimes happens cord arrangement was gotten to install the new The 25Z6 is not the most during moments that are quite simple and the re- "cabinet isolation capaci- common rectifier tube, and pregnant with tension, the

stringing was accomplished tor," a 0.005 -11F unit wired I didn't happen to have phone rang. Being the only

in a matter of minutes. between the chassis and one on hand. However, I one in the house (and be- the front panel. was able to buy a new -old- cause the ringing phone PANEL INSTALLATION After poking the leads stock replacement at a lo- was at my elbow and

AND FINAL WIRING from the speaker's output cal hamfest and had it couldn't be ignored), I had

With that done, I re- transformer primary down standing by to fill the empty to take the call. It was brief

mounted the dial plate and through their pass- through socket. Before installing it, I and, returning my attention

was ready to reinstall the grommet, I was ready to ran it by my tube checker, to the Tropicmaster, I could radio's front and rear pan- finish the last few wiring which gave it a clean bill of hear a reassuring low hum els. Those fasten, at their connections that would health. in the speaker when the bottom edges, to pairs of need to be made. Those That was something of a volume control was turned Bakelite spacers mounted included hooking up the relief because the original up full. Tuning around on

on the front and rear chas- output transformer primary 25Z6 had given no reading the broadcast band, I

sis apron (the idea is to to the push -pull audio -out- at all on the tester. I had heard a couple of faint insulate the front panel and put stage and wiring the never seen a tube with a stations.

cabinet from the chassis, choke back into the set's good filament not cause at Now I hooked up the which -being of AC/DC de- filter circuit. The last capaci- least a flicker on the meter outside antenna to the sign-has the potential of tor to be installed in the set and wondered if the fault Minerva's antenna post and being "hot' to ground). The (the second of the Iwo might be in the instrument. was gratified to hear many tops of the panels are fas- electrolytics) would also be But the moment of truth strong signals all over the tened together by a pair of installed in conjunction with had now arrived; it was broadcast band. Switching

72 transverse braces, which the wiring of the choke. smoke test time! Since the over to shortwave, I was

www.americanradiohistory.comAmericanRadioHistory.Com Minerva at last September's =III El= MI= \,)ealthy- AWA Rochester meet. He \° ,wer had just seen the first col------av\e \foad- umn on this series and NEW B eoè>-aoemed wanted to let me know that co`'`\ dop dial the set's cabinet-insulating for the Project Builder e dugh sev- spacer blocks were not c,oSível original, having been re- Electronic BP350- ELECTRONIC BOARD Board Games f-I placed by him some time I I passing GAMES $6.00 in the past. P.6ElNPUGrp, b. Twenty novel electronic board games g is prob- He also informed me that that you can build from the plans in this cf the cabinet had been book. Whether you are interested in nsformers. spray -painted by a prior motor racing, searching for buried trea- ,nat during owner. That would certainly sure on a desert island or for gold in Fort / Knox, spinning the wheel of fortune, or ,,K session- explain why the outside of doing a musical quiz -there is some- 411 give the Tropic - the radio looks so much thing for you to build and enjoy! r a complete better than the inside! How-

alignment, which will ever, I never suspected a PCP119- ELECTRONIC MUSIC (hopefully) return it to top repaint because the cab- D AND MIDI PROJECTS $14.95 operating condition. inet color was such a good Save cash by building the MIDI gadgets Looking into the pilot -light match to the front panel you need. Want a MIDI THRU box, pro- I (which still has its original problem, checked the gram change pedal,. Metronome, analog Tropicmaster's original spec- silk- screened control labels, echo unit, MIDI patchbay or switcher? ifications. They called for not to mention its rust spots, Over 16 practical and very useful music the usual type -47 (brown and so probably wasn't and MIDI projects -all in this book! The bead) 6-8-volt lamp. The part of the repaint project). projects are explained in detail with full lamp in the set was marked The paint also didn't look instructions on assembly. "6-8 volts," all right, but had new, perhaps because it a white bead. It also had a was done some time ago. F-1 BP301- ANTENNAS FOR VHF round bulb instead of the And, more important, the Antennas for AND UHF $6.00 UHF to elongated cylinder usual flamboyantly calligraphed VHF and From installing a TV or FM antenna setting up a multi- antenna array for on the type 47. silk-screened Tropicmaster shortwave listening or amateur radio, Searching through my logo on the cabinet's front this book explains the basics of VHF and stores, I was to find door -which would have able the UHF antenna operation and installation. proper lamp. It was marked been all but impossible to The text describes in easy -to- understand as a type 47, and had both mcsk for repainting -was in terms the essential information about a brown bead and the usu- perfect condition with no how antennas works, the advantages of al elongated envelope. sign of any overspray. Alan different antenna types, and how to get When that lamp was sub- tells me that this is due to the best performance from an antenna. stituted for the one his meticulous clean -up originally in the set, things with acetone. Mail to: Electronic Technology Today, Inc. returned to normal. Flare - Thanks, Alan! I think that P.O. Box 240 Massapequa Park, NY 11762 -0240 up was reduced to a prop- was the only true restoration Shipping Charges in USA & Canada er level and died down work done on the radio. My $0.01 to $5.00 $1.50 $30.01 to $40.00 $5.50 much more quickly. own efforts have been con- $5.01 to $10.00 $2.50 $40.01 to $50.00 $6.50 fined to making practical $10.01 to $20.00 $3.50 $50.01 and above $8.00 POSTSCRIPT FROM repairs and returning the $20.01 to $30.00 $4.50 THE PREVIOUS OWNER set to serviceable operat- Sorry, no orders accepted outside of USA and Canada. All I just received a note ing condition. payments must be in U.S. funds only. from Alan Douglas, from That's it for now. See you Number of books ordered. whom I purchased the al' next month. El Total price of books $ Shipping (see chart) $ Subtotal $ Sales Tax (NYS only) $ Total enclosed $ Name Address City State ZIP Please allow 6 -8 weeks for delivery. "He's waiting for he warranty to run out." = N = M

www.americanradiohistory.comAmericanRadioHistory.Com COMPUTER BI

By Jeff Holtzman I was just a kid when LEDs LEDs. For a couple of dol- When I was a kid, n came along (ca. 1965). lars, you could get perhaps ous magazines were Before LEDs, there were in- ten LEDs, of which six or publishing articles on el candescent lamps and seven wouldn't even work! tronics, parts were readily neon lamps. Incandescent I remember the thrill I available, and there was a lamps are available in a had when I connected my incredible feeling of innova- wide range of voltages, but first LED to a nine -volt bat- tion and experimentation. they have an insatiable ap- tery and a resistor. My ten - petite for electrons year -old perception of the LATER (current). Plus, they gener- world changed in an in- Fast forward about ten ate heat, they're fragile, stant, and my expectations years. A magazine called Soldering and they're simply not cool. changed forever. I couldn't Radio- Electronics published Neon lamps, on the other have articulated it at the plans for building a com- Irons And hand, have very low current lime, but something in me puter. Six months later, drain, and they do produce knew that the bulky old another magazine called Cyber Circuits a cool glow. But they re- vacuum -tube radios and Popular Electronics (then quire voltages much higher Ns were dead. They might owned by Ziff -Davis Publish- than are available in a not have known it yet, but ing Corp.) published its own they were dead; walking plans for a computer called dead perhaps, but none- the Altair. And the Altair

theless dead. I did know changed history.

that I wanted to have as The energy and innova- little as possible to do with tion once seen in electronics that dingy, dusty, hot, fragile, was now shifting to comput- high -voltage world of vac- ers, microcomputers. A new uum tubes; and as much as generation of magazines possible with cool, clean, (Byte, kilobaud, 80 Micro, miniature semiconductor and many, many others) devices like LEDs. sprung up to fuel that revo- I experienced a similar lution, and to profit from it. thrill when interesting, useful Only a few of those original integrated circuits were in- publications remain today, troduced. Devices like the and those in a much -al- 78xx series of voltage reg- tered format. Where once ulators totally changed the they catered to technical scope of project building. users and hobbyists, they Prior to the 78xx, just creat- focus now on business users ing a reliable source of and product reviews. That's power for a given project where the money is. But could consume a major where is the fire? part of the project. In fact, Look at it another way. As general -purpose, variable I define it, the "Golden Age power supplies were them- of Electronics" occurred As our world becomes ever more cyber, will the components and selves popular projects. (roughly) from 1965 -1975. test gear of our hobby give way to computer software and I remember when the The "Golden hardware? Age of Person- 555 "programmable" timer al Computers" occurred was introduced. Another from 1975 -1985. What hap- typical solid -state circuit. messy, repetitive problem pened between 1985 and They're also fragile. solved once and for all. 1995? And what will the I remember seeing ads I also remember when next decade bring? for the first LEDs. They were National Semiconductor expensive. Eventually, prices started introducing its LM VIRTUAL, CYBER, AND dropped, and surplus ven- line of audio amplifiers, pre- ARTIFICIAL dors and other retailers amplifiers, tuners, and so I experienced and par- 74 began selling grab-bags of on. Ditto. ticipated directly in those

www.americanradiohistory.comAmericanRadioHistory.Com first two Golden Ages. But ware on a hobbyist scale. then I entered the work The closest we've come is force, had my own family, projects based on micro - and settled into middle controllers, which represent age. I simply don't have the a real boundary- crossing same type of intuitive, cer- phenomenon between tain knowledge about the physical and cyber spaces. last decade as for those I'm not saying that no

preceding it. But I do have one uses a soldering iron - a theory (and you're wel- it hasn't come to that yet. I come to challenge it, am saying that fewer peo- confirm it, or confound it; ple are doing it, and of you can e -mail me at those who do, they do it not jkh @acm.org). The theory as a socially compelling goes like this: and captivating activity, as AN IMPORTANT PART

I believe that technically occurred in the 1960s and OF YOUR PHOTOCOPIER inclined youth need a 1970s. I don't know what the channel for communicat- next step will be. But given ISN'T PART OF ing, experimenting, both the popularity and the YOUR PHOTOCOPIER challenging, building. It is immaturity of the on -line- both an intellectual and a services industry in general, Having a machine may not permit you to photocopy social channel. I believe and the Internet in par- books, journals, newsletters and magazines. that prior to the 1960s, that ticular, my hunch is that The Copyright Clearance Center CAN. channel evolved much networking-internetwork- Contact us to find out slower. For perhaps as long ing -will be a strong area how you too can COPY RIGHT!SM as five decades leading up of growth. And there's no to the 1960s, that channel soldering on the net. COPYRIGHT CLEARANCE CENTER centered on vacuum -tube About ten years ago, in a 222 Rosewood Drive, Danvers, MA 01923 '&1. (508) 744-3350 Fax (508) 741-2318 electronics, ham radio, and discussion with a popular ©1993 Copyright Clearance Center shortwave listening. In the author of electronics proj-

1960s, things burst wide ects, I made the rash open. Technology started prediction that it wouldn't COMING NEXT MONTH to evolve much faster, and be long before people In the AUGUST 1995 issue of so did people. wouldn't know how to use a From roughly 1965 to soldering iron, that they 1985, hardware reigned in would never have seen a that channel, first in analog real resistor, capacitor, tran- electronics, then in digital sistor, or LED. I had a hunch electronics. Affer 1985, the that we would be building Popular Electronics channel turned 'Virtual" or "circuits" (or actually, cyber- " cyber." I dislike both words circuits) on computer That station went off the air minutes ago! Surprised because of their appropria- screens and viewing volt- exclamations like that one are uttered by many amateur tion by the technically ages and waveforms on operators and SWLers after hearing signals that appear to be seconds, or even minutes, late. What causes those delays? Are illiterate, but I have nothing simulated test equipment. aliens involved? The next issue of Popular Electronics will try to My Today, better to offer. Whatever friend laughed. answer those and other questions. you call it, the idea is that however, every issue of this PLUS.. . the underlying physical re- magazine advertises sev- ality became infinitely less eral such programs. A TV Transmitter: Build it and rebroadcast TV programs throughout house. important than the things The days of the soldering your you could do in the "ar- iron may soon be over. For Guitar Players: Coax some rock- and -roll distortion effects out of your favorite guitar with our preamp /distortion box. tificial" or "virtual" or " cyber" Long live the computer. space offered by the com- For the Workbench: Build our oscilloscope calibrator and use puter. it to check your oscilloscope's vertical gain, time base, probe compensation, and more! Affer 1985, people put down their soldering irons, And: Outstanding columns and departments like Gizmo, Think Tank, DX Listening, Scanner Scene, Multimedia Watch, Circuit and started to learn BASIC, Circus, and a whole lot more! C, or the script language of their word processor or mul- On Sale June 15, 1995 timedia- authoring environment. The reason is that it's won't believe what he's Pick Up Popular Electronics at your favorite Newsstand, to really "You hard do anything invented now." Bookstore, Convenience Store, or Supermarket new or interesting in hard- 75

www.americanradiohistory.comAmericanRadioHistory.Com ELECTRONICS MARKET PLACE

FOR SALE SECRET cable descramblers! Build your own FREE catalog. Chips, ICs, parts, products. descrambler for less than $12.00 in seven easy Amiga, C64/128, IBM, quality electronics. J.S.P., CABLE test chips. Jerrold, Tocom, S.A., steps! Radio Shack parts list and free descram- SSF, CA 94083 -5060. 24hrs. (415) 871 -5158. Zenith. Puts cable boxes into full service bling methods that cost nothing to try, included. model $29.95 to $59.95. 1(800) 452.7090, (310) Send $10.00 to: INFORMATION FACTORY, PO ZAP IT! For Jerrold or Pioneer cable boxes. Other 902 -0841. Box 669, Seabrook. TX 77586. For COD's (713) quality cable products too! Toll free: 1 (800) 922-3512 any time. 899 -9707. PARTS for $1.00. Resistors .25W 12, .5W 8. Capacitors .001uF 5, .01uF 5, .1uF 4, luF 3, 10uF 2, 100uF 1. Semiconductors 1N4004 4, 2N2222 1, 2N3904 2, 2N3906 2, TIP31A 1, TIP32A 1, LM741 CLASSIFIED AD ORDER FORM 1, LM555 1, LEDS red 3, green 2. Catalog $1.00, foreign add $1.00. ZIPFAST, Box 12238, To run your own classified ad, put one word on each of the lines below and send this form along with your check to: Lexington, KY 40581 -2238. Popular Electronics Classified Ads, 300 Experimenters Circuits - Complete in 6 500 -B Bi- County Boulevard, Farmingdale, N.Y. 11735 practical books using diodes, relays, FET's, LED's, IC 555's, and IC CA3130's for building PLEASE INDICATE in which category of classified advertising you wish your ad to appear. For blocks. Only $33.00 plus $6.00 for shipping. USA special headings, there is a surcharge of $11.00. and Canada only. US funds. ETT, INC., PO Box ( ) Plans /Kits ( ) Business Opportunities ( ) For Sale 240, Massapequa Park, NY 11762 -0240. (( )) Education/Instruction ( ) Wanted ( ) Satellite Television

ANTIQUE RADIO CLASSIFIED Special Category: $11.00 Free Sample! g. PLEASE PRINT EACH WORD SEPARATELY, IN BLOCK LETTERS. -,- rt (No refunds or credits for typesetting Antique Radio's `G errors can be made unless you clearly print or type your J' copy.) Rates indicated Largest Circulation Monthly. J ,,- are for standard style classified ads only. See below for additional Articles, Ads & Classifieds. EI charges for special ads. Minimum: 15 words.

6-Month Trial: $17.95. 1 -Yr: $34.95 ($51.95-1st Class). A.R.C., P.O. Box 802-L14, Carlisle, MA 01741 Phone:(508) 371 -0512 VISA/MC Fax:(508) 371 -7129 1 2 3 4 5

CABLE descramblers. Bargain headquarters, below wholesale prices. Absolutely the lowest 6 7 8 9 10 prices! Money-back beats us! AP ELECTRONICS,CT NICS, 1 (800) 304 3604. CABLE descramblers and test turn -on kits avail- 11 12 13 14 15 ($23.25) able for most makes and models. No catalog, no 800 number equals your lowest prices. Call others, then compare prices! We for our pay cash 16 ($24.80) 17 ($26.35) unwanted cable boxes. No Florida sales. (305) 18 ($27.90) 19 ($29.45) 20 ($31.00) 425 -0751. DESCRAMBLE cable with simple circuit added to Radio Shack RF modulator and using VCR as 21 ($32.55) 22 ($34.10) 23 ($35.65) 24 ($37.20) 25 ($38.75) tuner. Instructions $10.00. TELCOM, PO Box 832 - P7, Brusly, LA 70719. SURVEILLANCE Privacy security protection. 26 ($40.30) 27 ($41.85) 28 ($43.40) 29 ($44.95) 30 ($46.50) Catalog $5.00. SPY EMPORIUM, 6065 Hillcroft 414, Houston, TX 77081. (713) 774 -1000. 31 ($48.05) 32 ($49.60) 33 ($51.15) 34 ($52.70) 35 ($54.25)

We accept MasterCard and Visa for payment of orders. If you wish to use your credit card to pay for your ad fill BEST BY MAIL in the following additional information (Sorry, no telephone orders can be accepted.): Ratea: Write National, Box 5, Sarasota, FL 34230 BUSINESS OPPORTUNITIES GUARANTEED! BIG MAIL Home Based Businesses And Op- portunities. Only $5.00: J & M SPECIALTIES, 3403 Cameron Card Number Expiration Date Drive, Henderson, NC 27536. PERSONAL COMPUTER OWNERS CAN EARN $1000 to $5000 monthly offering simple services part time. Free list of 100 best services. C.B.C.A.Z, PO. Box 926168, Houston, TX 77292. PRINT NAME SIGNATURE MANUFACTURING GIANT SCREEN Projection TV'S. Big Profits, High Quality, Simple, Catalog $1.0 P &H: SP-Vision, IF YOU USE A BOX NUMBER YOU MUST INCLUDE YOUR PERMANENT ADDRESS AND PHONE Box 115, Taylor, PA 18517. NUMBER FOR OUR FILES. ADS SUBMITTED WITHOUT THIS INFORMATION WILL NOT BE ACCEPTED. EARN $3000.00 MONTHLY By Fax, FREE DETAILS FAX IN- CLASSIFIED COMMERCIAL RATE: (for firms or individuals QUIRIES TO: 412-343-5643. offering commercial products or services) $1.55 per word prepaid (no charge for ZIP code)...MINIMUM 15 WORDS. 5% discount for same ad in 6 PT /FT PEOPLE Needed To Prepare Labels At Home. Call issues within one year; 10% discount for 12 issues within one year if prepaid. NON -COMMERCIAL RATE: Now 1- 809 -474-2836. LD Toll. (for Individuals who want to buy or sell a personal item) $1.25 per word, prepaid.... no minimum. ONLY FIRST FINANCIAL WORD AND NAME set In bold caps at no extra charge. Additional bold face (not available as all caps) 306 per WANT FINANCIAL word additional. Entire ad in boldface, $1.85 per word. TINT SCREEN BEHIND ENTIRE AD: $1.90 per INDEPENDENCE? Send $1.00: RONNIE, word. 923 Realty, Carson, CA 90745. TINT SCREEN BEHIND ENTIRE AD PLUS ALL BOLD FACE AD: $2.25 per word. EXPANDED TYPE AD: $2.05 per word prepaid. Entire ad in boldface, $2.45 per word. TINT GUARANTEED LOANS weeks! SCREEN BEHIND ENTIRE WITHIN two No Income, EXPANDED TYPE AD: $2.55 per word. TINT SCREEN BEHIND credit checks! PLUS! $1,000 credit card! GUARANTEED AP- ENTIRE EXPANDED TYPE AD PLUS ALL BOLD FACE AD: $2.95 per word. DISPLAY ADS: 1" x 2Va $225.00; 2" x x PROVAL! Limit increased $300.00 annually! Reports, PRE- "- 21/4-$450.00; 3" 2 +W-$675.00. General Frequency APPROVED applications, $5.00. NEWSOM, 3352 Broadway, Information: rates and prepayment discounts are available. ALL Garland, TX 75043. COPY SUBJECT TO PUBLISHERS APPROVAL. ADVERTISEMENTS USING P.O. BOX ADDRESS WILL NOT BE ACCEPTED UNTIL ADVERTISER SUPPLIES PUBLISHER WITH PERMANENT ADDRESS OF INTEREST TO ALL AND PHONE NUMBER. Copy to be In our hands on the 13th of the fourth month preceding the date of HIGH SCHOOL DIPLOMA At Home, Accredited, Fast, "Failure- issue (I.e.; Sept. Issue copy must be received by May 13th). When normal closing date falls on Proof" 1- 800 -470 -4723, American Academy, 12651 S. Dixie Saturday, Sunday or Holiday, Issue closes on preceding work day. Send for the classified brochure. Highway, Miami, FL 33156. Circle Number 49 on the Free Information Card. MEXICO TRADE DIRECTORY $15.00 Postpaid. Box 661, Dal- Please make checks payable to Gernsback Publications Inc. 76 las, GA 30132.

www.americanradiohistory.comAmericanRadioHistory.Com HOME automation & computer control: Two -way EDUCATION /INSTRUCTION IR, two -way X -10, & hardwire. Control devices from serial computer link or stand -alone opera- FCC General Radiotelephone Operator's license. TIPS FOR MAIL ORDER tion. COMPCO, (615) 436 -5189 BBS, (615) Answers, solutions to latest 889 for elements 1,3 436 -6333 evenings. examinations. Prepared by professional engineer. PURCHASE To receive this publication, send $20.00 to T.V. Single dual cable CABLE Installers Manual. PO Box systems. Telephone poles, houses, apartments, UNIVERSAL COMMUNICATIONS, 11646, Palm Desert, CA 92255 -1646. It Is Impossible for us to verify the claims of ad- explained! Send $14.95 to INFOTEK, PO Box 71072, Milwaukee, WI 53211. LEARN VCR repair. Great profits. Home study. vertisers, including but not limited to product Free literature. 1 (800) and existence PRINTED circuit boards etched, drilled, tin P.C.D.I., Atlanta, Georgia. availability, credibility, reliability - -7070 Dept. VRH341. plated. Single sided $1.25/sq. inch. CHELCO 362 of warranties. The following information is pro- ELECTRONICS, 61 Water Street, Mayville, NY BECOME an electrician. Approved home study. vided as a service for your protection. It is not 14757. 1 (800) 388 -8521. Fax (716) 753 -3220. Free career literature. P.C.D.I., Atlanta, Georgia. 1 Intended to constitute legal advice and readers (800) 362 -7070 Dept. TEH341. CABLE TV equipment & accessories. Whole- are advised to obtain independent advice on salers welcome! 30 day moneyback guarantee! LEARN PC repair - troubleshooting, servicing. how to best protect their own interests based Free cata ! PERFORMANCE ELECTRONICS, Home study. Free literature. P.C.D.I., Atlanta, upon their individual circumstances and juris- INC.,1(: i)815.1512. Georgia. 1 (800) 362 -7070 Dept. JJH341. dictions. UNDETECTABLE Cable /satellite descrambler will work on all systems guaranteed! Serd 1. Confirm price and merchandise information SASE -info, $98.95 -kit, $14.95 -plans. MYSTICAL ELECTRONICS, PO Box 481 Cooper Station, SATELLITE TELEVISION with the seller, including brand, model, color or New York, NY 10276. rebates included in the EXCLUSIVE new 18" satellite broadcast network finish, accessories and FREE: Send name & address for unique gifts & with multi -educational programming. Extra busi- price. collectable catalogue. A & J THINGS, PO Box ness opportunity and more! 1 (800) 899 -9707. 879, Dept. PE, Apple Valley, CA 92307. 2. Understand the seller's return and/or refund including the allowable return period, who ELECTRONIC sales installation of Intruder ID policy, security systems for home, apartment, or busi- BUSINESS OPPORTUNITIES pays the postage for returned merchandise and ness, call (812) 295 -4240. whether there is any "restocking" or "return" THE Case Against Patents. Thoroughly tested EASY work! Excellent pay! Assemble products at charge. home. free 1 (800) 467 -5566 ext. 5730. and proven alternatives that work in the real world. Call toll $28.50. SYNERGETICS PRESS, Box 809 -C, START your own technical venture! Don Lan- 3. Understand the product's warranty. Is there Thatcher, AZ 85552. (520) 428 -4073. Visa /MC. caster's newly updated Incredible Secret Money a manufacturer's warranty, and if so, is it for a II how. We now have T.V. notch filters, free brochure, MICROTHINC, Machine tells autographed U.S. or foreign manufacturer? Note that many copies of the Guru's underground classic for Box 63/6025, Margate, FL 33063. (305) manufacturers assert that, even if the product 752 -9202. $18.50. SYNERGETICS PRESS, Box 809 -C, Thatcher, AZ 85552. (520) 428-4073. Visa/MC. comes with a U.S. manufacturer's warranty, if you GET paid $268.20 per roll taking easy snapshots! purchase from an unauthorized dealer, you are No Film supplied. PHOTOTEK, Box not covered by the manufacturer's warranty. If PLANS & KITS experience. 2457, Dept. 2, Pinecove, CA 92549. Recorded in doubt, contact the manufacturer directly. In information: (909) 659-9757 ext. 8. 60 Solderless Breadboard Projects in two easy - addition to, or instead of the manufacturer's war- to pocket books. Complete with circuit de- -read INCREDIBLE opportunity! New 18" satellite ranty, the seller may offer its own warranty. In scriptions, schematics, parts layouts, component system sells itself! Now you can participate in "the either case, what is covered by warranty, how listings, etc. Both books (BP107 & BP113) only most lucrative business opportunity of the 90's!" 1 $11.90 plus $4.00 for shipping. USA and Canada (800) 899-9707. long is the warranty period, where will the prod- PO Massape- only. US funds. ETT, INC., Box 240, uct be serviced, is there a charge for service, what qua Park, NY 11762 -0240. COMPUTER profit secrets revealed! Discover many homebased businesses. Free information. do you have to do to obtain service and will the SURVEILLANCE /countersurveillance, bugging/ S. B. COMPANY, 51 MacDougal Street #24E, product be repaired or replaced? You may want phone tapping detector, telephone /fax encryption, New York, NY 10012. vehicle tracking, covert video, transmitter kit, and to receive a copy of the written warranty before more...A.B. ELECTRONICS, 1 (800) U -ANTI- placing your order. BUG. 4. Keep a copy of all transactions, including CRYSTAL set Handbook - Visit antiquity by INVENTIONS grandfather built. Assem- but not limited to cancelled check, receipt and building the radios your FREE Invention package: DAVISON & ASSO- a that work and For phone orders, make a note ble "Quaker Oats' rig, wind coils CIATES offers customized development, patent- correspondence. make it like 1920's! $10.95 plus look the Only ing, and licensing for new products and ideas. of the order including merchandise ordered, price, $4.00 for shipping and handling. CLAGGK INC., Proven results: 1 (800) 677 -6382. salesper- PO Box 4099, Farmingdale, NY 11735. US funds order date, expected delivery date and only! USA and Canada - no foreign orders. son's name. FIBER optics experimenters parts, supplies 5. If the merchandise Is not shipped within the and tools: Fiber, cable, connectors, splices, de- NEW DESCRAMBLER no was with- tectors, lasers, kits, plans, newsletter. Send $2.00 TECHNOLOGY REVEALED promised time, or if time promised, for catalog. LIGHTLINE ENGINEERING, PO Box in 30 days of receipt of the order, you generally 24, Mullica Hill, NJ 08062. REVEALED Halcyon's new universal 4000 de- have the right to cancel the order and get a re- My manuals /kits all universal MINI -transmitters. Low to high power! Voice scrambler! perfects fund. descramblers guaranteed. SNOW, POB 22048, changers and much more! Send $2.00 for infor- Lansdowne, St. John, Canada E2K 4T7. mation. PARSEC ELECTRONICS, PO Bcx 8. Merchandise substitution without your ex- 34594, Phoenix, AZ 85067. press prior consent is generally not allowed. PRECISION power zener diode kits. Available a with your order or the assembled and calibrated to your voltage specs. PROGRAMMABLE LOGIC 7. If you have problem Build inexpensive IC power supplies with custom merchandise, write a letter to the seller with all the LOW -cost FPGA training kit teaches you FPGA split voltages. Free info. Write LINTON, 325 pertinent information and keep a copy. Marston, Suite 212, Glen Ellyn, IL 60137. design for only $165.95. Includes textbook, programming software, experimenter's board, re- from SURVEILLANCE schematics. State of the art de- useable 3500 -gate FPGA chip. Money -back 8. If you are unable to obtain satisfaction signs. Large selection. Free literature. guarantee. Contact XESS CORP: 1 (800) the seller, contact the consumer protection STACKHOUSE, POB 502, Dayton, OH 549 -9377 or devb@ vnet.net. agency in the seller's state and your local Post 45401 -0502. Office. FREE phone calls through your CB radio. Project plans $5.00. DB INTERNATIONAL, POB 1933, If, after following the guidelines, you expert - Lynnwod, WA 98046. MASTERCARD AND VISA are now accept- ence a problem with a mall order advertiser ed for payment of your advertising. Simply that you are unable to resolve, please let us complete the Classified Ad order form and know. Write to Advertising Department, WANTED we will bill you. Gernsback Publications Inc., 500B BI- County Blvd. Farmingdale, NY 11735. TEST equipment repair, including power supplies, THIS IS A BOLDFACE EXPANDED AD. If and other measuring devices, excluding oscilloscopes, power supply repair of computer you like this format, request it. Your cost Be sure to Include copies of all correspondence. equipment, call (812) 295 -4240. is $2.20 per word. 77

www.americanradiohistory.comAmericanRadioHistory.Com CIRCUIT CIRCUS

By Charles D. Rakes ather around, cir- a single sample- and -hold to RECORD, pin 27 (PA) and cuiteers, because this circuit, and then record it in pin 24 (PD) of U1 go low. visit we're going to investi- one of 128,000 EEPROM Holding down switch S1 will gate a most interesting cells. That amount of mem- then cause pin 23 (CE) to voice -record/playback inte- ory allows the storage of a go low. That starts the re- grated circuit. It's the 20- second sample with 8- cording process and ISD1000A Direct Analog bit accuracy. After the data activates the electret mi- Storage Technology (DAST) has been stored in the crophone, MICI. IC manufactured by Infor- EEPROM, the memory is During recording, LEDI mation Storage Devices; maintained without power. will remain on and will go the chip is available from Only a minimum amount out when the end of mem- Radio Shack (catalog no. of external components are ory is reached. Letting go 276 Voice -1325), as well as other required to build a com- of switch S1 will stop the sources. That neat little 28- plete voice recording and recording process. If the re- Recording and pin chip stores data in ana- playback system. The pre- cording is stopped before log form in a special amplifier, filters, AGC, power the end of memory is Playback EEPROM requiring neither amplifier, control logic, and reached, an end- of -mes- an analog -to- digital nor a analog storage are all in sage bit is set internally to digital -to- analog converter. the same chip! mark where the message The ISD1000A can sample ended. That allows other an audio signal at a 6.4 -kHz SIMPLE RECORDER/ messages to be recorded rate, store each input bit in PLAYER in a sequential manner until Our first entry is a record- the total memory is used +5V er /player circuit (see Fig. 1) up. Cl C2 C6 that is similar to the one Setting switch S3 to PLAY 1 .1 47 shown in the IC's data causes pin 27 to go high, SPKR1 sheet. When switch S3 is set and pin 24 to go low. To 16 28 14

2 R6 PARTS LIST FOR THE 3 1052 15 SIMPLE RECORDER /PLAYER (Fig. 1) 4 1N 1111- 20 +5V 5 SEMICONDUCTORS U1 6 ISD1000A U1- ISD1000A voice record /playback, integrated circuit 21 9 QI-2N3904 NPN transistor LEDI-Light -emitting diode, any color 10 17 RESISTORS R1 S 12 (All resistors 1/4-watt, 2.2K} 13 are 5% units.) RIR3 -2200 -ohm S1 26 R4 -4700-ohm Z 23 -O o--* CE R5- 470,000 -ohm S2 18 R6-10 -ohm Z 24 R7- 10,000 -ohm PD R8-470-ohm 27 25 22 +5V P/R EOM R2 CAPACITORS 19 R7 2.2K 10K R8 C1, C2-0.1 -µF, ceramic -disc 4700 C3, C4 0.22 -µF, C5 Mylar PLAY + 4.7 0.7 16 -WVDC, electrolytic O S3 C6, C7 -47 -11R 16 -WVDC, electrolytic

RECORD R5 LEDI ADDITIONAL PARTS AND MATERIALS Q1 470K 2N3904 SI, S2-Pushbutton switch, normally open S3 -SPDT switch MICI- electret microphone Fig. 1. This basic recorder /player circuit is easy to use. Turn S3 SPKR1 -8 -ohm speaker to RECORD and hold down SI to record your message. To play it Wire, solder, etc. 78 back, turn S3 to PLAY and press S2.

www.americanradiohistory.comAmericanRadioHistory.Com +5V -- R2 R4 47K 47K PARTS LIST FOR THE R1 R3 PICTURE -FRAME AUDIO (Fig. 3) 47K 47K o AO ISD1000A voice record /playback, integrated circuit 2 Ul- o- Al R1 -10 -ohm, 1/4-watt, 5% resistor -disc capacitor 3 CI, C2- 0.1 -p.F, ceramic A2 C3-47-11F, 16 -WVDC, electrolytic capacitor 4 SI- Pushbutton switch, normally closed A3 U1 SPKR1 -8 -ohm speaker 5 ISD1000A Wire, solder. etc. o

9 +5V o- A6 +I C7 10 C2 A7 47 1 R5 R7 R1 SPKR1 47K 4. 47K 7' 47K R6 R8 16 28 47K P 47K 14 +5V Fig. 2. Adding an 8- position DIP switch to the ISDI000A makes R6 3 100 it possible to find a particular location in the 20 seconds of 15 4 message time. +5V 5

6 R3 9 2.2K PARTS LIST FOR THE c4 MESSAGE -START LOCATOR (Fig. 2) 10 U1 .22 ISD1000A 12 Ul- ISDI000A voice record/playback, integrated circuit R4 13 4.7K R1 R8- 47,000 -ohm, 1/4-watt, 5% resistor 26 MIC1 S1 -8- position DIP switch Wire, solder, etc. C8 R2 47 8 47K 23 I W C5 24 .22 begin playback, switch S2 must be depressed mo- D1 27 19 1N914 mentarily to set pin 23 low. ¡ R5 MESSAGE -START 470K O IA Si LOCATOR El

II PAY RECORD Pins 1-6, 9, and 10 can be used to address the ISD1000A for multiple mes- Fig. 4. This recorder /player is real easy to use. Hold down S2 to sages. Those pins control an record a message and then hold down Si to play it back. internal register called the Message Start Pointer, or segments of 0.125 seconds 0.125; that equals 80. Be- MSP The MSP indicates the each. The address -input cause the address inputs location where the next decimal values are as fol- use positive logic, switches record or play operation lows: AO = 1, Al = 2, A2 = S1 -e (decimal value of 16) will begin. 4, A3 = 8, M = 16, A5 = and S1 -g (decimal value of So, how do you find a 32, A6 = 64, and A7 = 128. 64) are placed in the open particular message loca- To start the recording or position to obtain the deci- tion to either begin playback function at a de- mal value of 80. All other playback or recording? To sired time (MSP), divide the switches must be closed. do that, an eight- section time in seconds by 0.125. DIP switch, S1, must be con- That will be the decimal PICTURE -FRAME nected to the eight address number that is set by the AUDIO inputs of the IDS1000A (see address switches of S1. As Now that we know how Fig. 2). Address inputs an example, to start the to make the ISD1000A per- AO-A7, which correspond recording or playback form, it's time to have some to switches S1 -a to S1 -h, Fig. 3. This circuit could function at the 10- second fun. Add the simple play- allow you to split the mes- make a favorite picture frame point of memory, you would back circuit shown in Fig. 3 sage area into 160 equal speak out. have to first divide 10 by to a photo of a special 79

www.americanradiohistory.comAmericanRadioHistory.Com PARTS LIST FOR THE +6V ADVANCED RECORDER /PLAYER (Fig. 4) C1 C2 C9 01 1 1 47 1N4002 -1r RESISTORS v (All resistors are 1 -watt, 5% units.) 16 28 - Rl, R2- 47,000 -ohm 14 R3- 2200 -ohm 2 R11 3 R4-4700-ohm 1052 15 A R5- 470,000 -ohm 4 SPKR1 -ohm R6-l0 5

CAPACITORS 6

Cl. C2-0.1 -1.F, ceramic -disc 9 C3 C5- 0.22 -RF, Mylar U1 10 C6- 4.7 -µF 16 -WVDC, electrolytic ISD1000A C7. C8- 47 -4LF, 16 -WVDC, electrolytic 12 13 ADDITIONAL PARTS AND MATERIALS Ul- ISD1000A voice record /playback, integrated circuit 26 C3 Dl -1N914 silicon diode ... R2 .1 SI, S2- Pushbutton switch, normally open 47K 23 MICI- electret microphone 1M 1 SPKR1 -8 -ohm speaker R1 24 Wire, solder, etc. 47K D4 27 1 N914 R3 2.2K N4A R10 R6 PARTS LIST FOR THE LEDI' Q3 l 10K 1K SOUND -ACTIVATED PLAYER (Fig. 5) C8 ' 2N3904 R9 47 R5 220K 4.7K SEMICONDUCTORS R4 R7 U1- ISD1000A voice record/playback, integrated circuit C5 4.7K R8 10K Ql Q3- 2N3904 NPN transistor C6 .22 220K DI- IN4002 silicon rectifier 4.7 diode ` 'w I( I IE- D2 D4 -IN914 silicon diode K c4 D2 C7 LEDI- Light- emitting diode, any color .22 1N914 47 2N3904 RESISTORS D3 1 N914 (All resistors are 1/4-watt, 5% units.) MICI = R1, R2- 47,000 -ohm R3- 2200 -ohm R4, R5 -4700 -ohm Fig. 5. When this circuit "hears" a noise, it plays back a R6 -1000 -ohm prerecorded sound, such as a dog barking. R7, R10- 10.000 -ohm R8, R9- 220,000 -ohm in Fig. 3 is a good choice ing all component leads R11 -10 -ohm for the photo caper be- short and close to the IC. CAPACITORS cause it makes it impossible Using the solid -state re- CI C3- 0.1 -µF, ceramic -disc to accidentally erase a corder is easy. To record, C4, 0.22 -RF, Mylar C5- message which at a later depress switch S2 and hold C6, C7- 4.7 -11F, l6 -WVDC, electrolytic date might be impossible it closed until you have C8, C9 -47 -RF 16 -WVDC, electrolytic to recreate. So how do you completed your message ADDITIONAL PARTS AND MATERIALS get a message onto the or until the 20- second mes- MICI- electret microphone chip? Simply use either the sage limit has run out. To SPKR1 -ohm speaker -8 circuit in Fig. 1 or Fig. 4 (we'll play the message back, Wire, solder, etc. get to that in a moment) to hold switch S1 closed. record the message and then move the chip to the SOUND -ACTIVATED friend or relative and you frame is resting in place, playback -only circuit. PLAYER can have his or her looks the switch is open. When Now let's take a look at a and voice frozen in time. the picture is picked up, the ADVANCED RECORDER/ sound -activated talk -back Place the circuitry in a small switch will close and the PLAYER circuit (see Fig. 5). One plastic case and attach it frame will appear to speak. Our next entry (see Fig. 4) great application for the to the back of the picture. Of course, that might cause is a mini solid -state mes- circuit is as a simulated Mount S1, the normally the person holding the sage recorder /player watchdog. You could rec- closed pushbutton switch, frame to drop it when it circuit. To keep Murphy at ord the sound of a barking on the bottom of the case starts talking! bay, follow good project- dog onto the ISD1000A 80 so that when the picture The playback -only circuit building practices by keep- using either of the recorder

www.americanradiohistory.comAmericanRadioHistory.Com circuits we already exam- THINK TANK Coil Design and ined, insert the chip into the Construction YOU CAN WIND (Continued from page 32) Manual sound -activated player, and locate the circuit near an YOUR OWN COILS? entry door. When someone change R1 from 240 ohms There's no trick to it except knowing what bangs on the door a fero- to 1000 or 1200 ohms. you are doing. In a unique, 106 -page book cious dog will bark back. -Bill Stiles, Hillsboro, MO you can become expert in winding RF, IF, With a little thought, I am The values of R1 and R2 audio and power coils, chokes and trans- sure you can come up with are not too important; their formers. Practically every type of coil is dis- other uses for the circuit. ratio is. That's why the ratio cussed and necessary calculations are given An electret microphone, of the values in the spec with the mathematical data simplified for use by anyone. Get your MICI, picks up sounds sheet is The same as that copy today! which are amplified sev- shown here. The 240- and eral- hundred times by 2400-ohm values are hard rMail coupon to: transistors Q1 and Q2. The to find (even at Radio Inc. audio output at the collec- Shack), and that's probably Electronics Technology Today, tor of Q2 feeds a voltage - why Joseph used more - P.O. Box 240 Massapequa Park, NY 11762 -0240 aside, doubler detector circuit common stock. That Please send me my copy of Coil Design and Construction Manual about using that supplies a positive bias your comment (BP160). I enclose a check or money order for $8.45 to cover the to Q3. Transistor Q3's collec- precision units or an ad- book's cost and shipping- and -handling expenses. NY state resi- tor then goes low, lighting justable circuit is well taken, dents must add local sales tax. LEDI and forcing pins 23 Regarding R3, the circuit Name and 24 of U1 low. That starts is designed to be a trickle the play function. As long as charger-a 1 -amp current Address the sound level reaching draw is not a trickle, The City State ZIP the microphone is sufficient circuit is supposed to keep to keep Q3 on, the record- batteries at The ready, not All orders must be paid in U.S. funds only. Sorry, no orders ac- ing will continue to play to recharge them after a cepted outside of USA and Canada. Please allow 6 -8 weeks for de- until the 20- second time significant drain. For that every. period runs out. When the reason, the drop across D1 audio reaching the micro- is insignificant. It can also phone ceases, the be overcome by adjusting playback will stop within a the value of R2 Placing a few seconds (the value of crowbar diode across a C7 determines how long regulator in most power - that is; increase the value of supply circuits is a good C7 to make it longer, and idea. But in this case, using ON WATCH FOR reduce the value to make it to replace D1 still does not the time period shorter). prevent the battery from AMERICA. The next time the circuit is discharging Through the re- activated, the playback will sistors if the charger losses start over at the beginning power. As shown, D1 pro- and repeat the message. tects both the regulator While the circuit is not and the battery. playing, power consump- You are absolutely right tion is only a few milliamps. about the value of R4-it's When pins 23 and 24 of U1 too low. I generally shoot for are high, the IC is in a sleep an LED current of 15 mA, mode drawing only about but LED life should not be 10- microamps of current. significantly reduced with If you would like to in- your value of 20 mA. How- crease the playback audio ever, I generally round -up a On ships, planes and submarines, in locations level, you can connect an current- limiting resistor's val- around the world, the men and women of the external amplifier to the cir- ue to the next standard United States Navy are on watch. They re putting cuit. The audio can be value, not down. That pro- their training to work in jobs that make a difference, taken from either pin 14 or vides a tiny safety margin. while developing skills they 11 need for a successful 15 through a suitable coup- That's all until next month. future. Just as important, they re doing it for their ling capacitor. In the meantime, send your country. They re Navy people, working hard for That's all for now. If you circuits to Think Tank, Popu- America. And that makes us proud. would like to see more on lar Electronics, 500 -B Bi- the ISD1000A, check out the County Blvd., Farmingdale, Navy. Full Speed Ahead. "Circus" next month. NY 11735. 81

www.americanradiohistory.comAmericanRadioHistory.Com DX LISTENING

By Don Jensen Some SWLs abandon eastern Pennsylvania for a "In addition, don't forget their listening during weekend of alfresco listen- to bring along the other the summer months. More ing fun. This month, Rich things you'll need for your static, some say, and yes, continues with his answers SW listening, maybe a tape

there's some truth to that. to questions I put to him recorder to capture those For others, there are too about organizing a SW DX- rare SW signals you hear, many other outdoor ac- pedition. reference books, frequency tivities to compete with DX What goes into planning lists and the rest." listening, and that's true too. a shortwave DX outing, How about creature But before you pull the plug Rich? comforts? on shortwave listening until "In addition to bringing "Our cabin is comfort- Fun in the autumn, be aware that if along the receivers and able and little more than you're up to battling the other gear, it is wise to plan an hour's drive away for Summertime band noise, there can be your listening time. You want most of us. And we all cook, some terrific DX out there. to maximize the oppor- sort of. I'm in charge of the Summertime can pro- tunities to catch those DX traditional Friday -evening duce some of the best signals when they appear. spaghetti dinner. Fred trans- equatorial signals to "Have a list of 'target' brings lunch meats and stations ready to go. Since, rolls. Hans has made his hopefully, you are in a DX- breakfast muffins legendary. UNITED NATIONS RADIO ing environment that's Dave's mom has supplied 4Q LA RADIO DES NATIONS UNIES better and quieter than us with delicious pies...." home, don't `. IIV PAANO 06bEANHEHHbIX HAuNH be afraid to Okay, okay, Rich, we get stretch your listening goals the idea. Is there an ideal LA RADIO DE LAS NACIONES UNIDAS and interests. size for a DXped!tion "For example, maybe group? you've never heard a SW "Four or five, and their station from Indonesia be- listening setups, fit easily in fore. Decide in advance a cabin. More can fit in with which frequencies and a bit of crowding, but a Thanks,. Mr..Jensen, for the report times may give you the best larger group means plenty 0815 -0830 QIT, 26 Oct. on a United Nations broadcast at opportunities. Then, with a of enjoyable conversation on IQ19H,. 9,53.5 toe.... the details of which are correct. good propagational open- and storytelling. And it's nice ing and reduced band to have the extra ears lis- RADIO DIVISION noise, Indonesian reception tening for the rare DX DEPARTMENT OF PUBLIC INFORMATION may become a reality!" signals. Here's a vintage QSL card from United Nations Radio, which at What sort of DXing equip- "Actually, though, we've the time was rebroadcast via the powerful Voice of America ment should one bring had DXpeditions with as shortwave transmitters. along? few as two people and we "At more primitive loca- had a ball. What's impor- Northern Hemisphere SWLs. tions, battery portables tant is that everyone has Those signals can include would be required, but similar DX interests." some very elusive African since the cabin where we What about antennas? and South American SW set up has electrical power, "Gifford Pinchot State ones. And, as I suggested that's not a concern for us. Park in eastern Pennsylvania last month, you can add "Today's AC- powered is a wooded area, which more fun to your summer tabletop SW sets are light- allows the opportunity to SWLing by doing at least weight and compact, experiment with antennas, some of it in the great excellent for our SWLing in more so than back home. outdoors. the 'wild.' But one of our We've tried truly long, long - In our June column, long- guys, Hans has brought wire antennas. We've used time DXer Rich D'Angelo along his old and very special switching arrange- told us about his regular heavy military surplus R-390 ments to couple several DXpeditions with a group of tube receiver, which is a antennas to a receiver. 82 friends to a state park in real 'boat anchor.' We've experimented with

www.americanradiohistory.comAmericanRadioHistory.Com 'delta loops' and 'eaves- picture of an SWLing week- world. But in 1985, faced attention to some of the SW droppers,' and they've end. with a hike in airtime broadcasts that are being worked well. charges levied by the VOA, logged on the bands these are you hear- "I may be an antenna AN INTERESTING IDEA the U.N. decided it could days. What cynic, but I'm convinced In an Op Ed think piece no longer afford to lease ing? Drop a line to me in Pop- that in a low -noise environ- in the New York Times, Keith the facilities. care of 'DX Listening," ment, just 100 feet of wire Spicer, chairman of the Ca- The United Nations, of ular Electronics, 500 -B Bi- produces as good results as nadian Radio -TV and course, didn't abandon ra- County Blvd., Farmingdale, almost any other antenna Telecommunications Com- dio entirely. It continued to NY 11735. combination. Our long an- mission, noted that hate furnish brief weekly news CUBA-9,820 kHz. Radio tennas are simply strung broadcasts have helped to and current -event pro- Havana Cuba was heard at over low tree branches. At brew some of the worst grams to world SW 0345 UTC with its English - the state park, fortunately, horrors in places like Bosnia broadcasters willing to re- speaking shortwave -listeners program, "DXers there is no shortage of tree and Rwanda. broadcast them. Today, branches. Although we'd In those trouble spots, the those continue, broadcast Unlimited," with host Arnie love to leave them up, mak- United Nations staggers un- by just a handful of stations Coro. It's also on 6,010 kHz ing for a more permanent der huge peacekeeping in places like Nigeria, Egypt, at the same time. kHz. Radio installation for our next visit, bills that are a result of China, Zambia, Poland, and JAPAN -11,885 that's not possible in the those conflicts. Couldn't the others. Japan, out of Tokyo, was park. We put them up when UN head off or stop ethnic Needless to say, the im- noted at 0530 UTC with an we arrive and take them wars by mobilizing airwaves pact of these broadcasts is English -language feature, down when we leave. that are too often used to insignificant. So maybe then into Japanese pro- has a worthy idea. gramming at 0600 UTC. "Although I wouldn't rec- set them off? Spicer ommend going on a Spicer notes that broad- Maybe U.N. Radio should MOROCCO -17,595 kHz. DXpedition with only the casts can convey anti -racist be beefed up to air "Propa- Radio TV Morocaine was portable receiver's built -in facts and perspectives in ganda for Peace." logged at 1400 UTC an- whip antenna, Larry man- the same powerful way that nouncing, "Welcome to the aged to log the Indonesian broadcasts now are used to DOWN THE DIAL International Service of Ra- station, RRI Tanjunkarang on inflame ethnic hatreds. Un- Time again to turn our dio Morocco." 3,395 kHz two years ago on like the print media, radio a Sony 2010 with just its can reach all social and whip. Since the station was cultural groups, especially booming in on our Drakes the illiterate or poorly edu- From Not -Workin and NRDs with long wire cated, he points out. 'Beverage' antennas, he Broadcast stations require to Networking! thought it worth a try with only a modest amount of the portable and whip. It equipment and supplies, Troubleshooting worked, but I wouldn't ex- and only a few staff mem- Local -Area Networks! pect results like that on a bers. Volunteers from the the first regular basis." West's private media -aid or- Now, complete for Any other tips? ganizations could be time in one detailed booklet! to help the U.N., "Be careful during hunt- enlisted Gain a fuller knowledge of network ing season? Stringing an Spicer suggests. fundamentals and how they antenna in the woods, and "We're talking about developed from the early days of hearing gunshots in the dis- technology, a few volun- main frames, from XNS to Ethernet tance, can shorten a teers and some vision -all technology, the OSI stack for longwire antenna faster at a pittance -to stop eth- interconnecting different computers, than bad weather! And the nic bloodbaths," Spicer basic and specialized test instruments, etc. Several usual camping -out cautions says. tough LAN case histories bring from theory to the also apply. Longtime SWLs re- practical side of troubleshooting. 'As far as our group is member that the U.N. once concerned, another safety was a major presence on CLAGGK Inc., Reprint Bookstore tip is to keep Hans away shortwave. U.N. Radio, then P.O. Box 4099, Farmingdale, NY 11735 Voice from the stove. He earned relayed by powerful Please rush my copy of "From Not -Working to Networking." I enclosed the nickname 'Torch' last of America transmitters, was payment of $5.00 which includes shipping charges. year when he almost easily heard around the Name burned the cabin down Address a shrimp CREDITS: Richard D'Angelo, while cooking State ZIP PA; Marie Lamb, NY; Ed City dish. It made for some Rausch, NJ; Robert Tucker, GA; great conversation and pic- Sorry, no orders excepted outside of United States and Canada. All North American SW Associa- Payments must be in U.S. funds. Send check or money order payable to tures!" tion, 45 Wildflower Road, CLAGGK Inc. -do not send cash or stamps. New York State residents Thanks, Rich, for your vivid Levittown, PA 19057. add applicable sales tax. 83

www.americanradiohistory.comAmericanRadioHistory.Com HAM RADIO

By Joseph J. Carr, K4IPV Although transmitter interference. Or to put it An implication of the fact power is often the first another way, it's the ability that radio signals have thing a ham looks at when to reject interference from bandwidth is that the re- looking for a transceiver, signals on frequencies ceiver must have sufficient that's actually one of the close to the desired signal bandwidth to recover all of least important specifica- frequency. the signal. Otherwise, infor- tions. For overall operating In order to understand mation might be lost, Receiver usefulness, the specs of the the selectivity requirements resulting in distorted audio. receiver are much more of a receiver, you must first On the other hand, allow- Selectivity important. And among re- understand a little bit of the ing too much bandwidth ceiver specs, one of the nature of real radio signals. increases the noise picked most important is selectivity. An unmodulated radio car- up by the receiver and rier theoretically has an thereby deteriorates the infinitesimal bandwidth (al- signal -to -noise ratio. The though all real unmodu- goal of the selectivity sys- lated carriers actually have tem of the receiver is to a very narrow bandwidth match the bandwidth of because they are modu- the receiver to that of the lated by noise and other signal. That is why receivers artifacts). As soon as the will use a 270 to 500 -Hz radio signal is modulated to bandwidth for CW, 2 to 3 carry information, however, kHz for SSB, and 4 to 6 kHz the bandwidth spreads. An for AM signals. They allow on /off telegraphy (CV sig- you to match the receiver A nal spreads out on either bandwidth to the transmis- side of the carrier frequen- sion type. cy by an amount that The selectivity of a re- depends on the sending ceiver has a number of speed and the shape of aspects that must be con- the keying waveform. Figure sidered. Those are the front- 1A shows an unmodulated end bandwidth, IF band- CW signal. When the carrier width, IF shape factor, and is keyed, however, the sig- more. I nal spreads out as shown in L c tH Fig. 1B, with a bandwidth FRONT-END centered on the carrier of BANDWIDTH B fH -fL. The "front-end" of a mod- Fig. 1. An unkeyed carrier (A) An AM signal spreads out em superheterodyne radio has only a very small an amount equal to twice receiver is the circuitry that bandwidth, but when the the modulating frequen- is between the antenna in- carrier is keyed, the signal cies. That means that the put terminal and the first spreads out as shown in B. AM waveform will occupy a mixer stage. Front -end se- spectrum that is equal to lectivity is the key factor Of course, sensitivity, dy- the carrier frequency (fc) that keeps out -of -band sig- namic range, third -order plus /minus the audio band- nals from raising havoc with intercept point, and other width. For example, in the the receiver. For example, matters are important as case of an AM transmitter AM- broadcast band trans- well, but in the limited with audio components mitters located near your space that a column af- from 300 to 3,000 Hz trans- 6TH can easily overload a fords us we can tackle only mitting on a carrier poorly designed shortwave one topic at a time ... so frequency of 14,300 kHz, the receiver. Even if those sig- this month it's selectivity. upper and lower sidebands nals are not heard by the Selectivity is the measure will extend from 14,297 kHz operator (as they offen of a receiver's ability to re- to 14,303 kHz (fc ± 3,000 are), they can desensitize a 84 ject adjacent -channel Hz) as shown in Fig. 2. receiver, or create harmon-

www.americanradiohistory.comAmericanRadioHistory.Com lectivity also helps improve receiver's first -IF frequency. a receiver's image- rejection For example, if your receiver and 1st -IF- rejection ca- has a first IF of 8.83 MHz, it pabilities. All superhetero- must be able to reject radio dyne receivers are subject signals operating on that to image responses. An im- frequency when the re- age is the response to a ceiver is tuned to a different signal that is located at a frequency. Although the point that is the RF frequen- shielding of the receiver is cy plus /minus the IF on the also an issue with respect to other side of the LO from that performance, the front- the RF signal. In the exam- end selectivity affects how ple shown in Fig. 3, the LO is well the receiver performs on the low side of the RF against 1st -IF signals. If there signal, so the IF frequency is is no front -end selectivity to 4f, or RF - LO. But if there is discriminate against signals a signal at frequency f, it at the IF frequency, then also is Af from the LO, so it is they arrive at the input of 14,297 14,300 14,303 seen as a valid IF signal by the mixer unimpeded. De- RF FREQUENCY (kHz) the receiver! pending on the design of If the IF frequency is low the mixer, they then may Fig. 2. Assuming an audio spectrum of 300 Hz to 3,000 kHz, and compared to the RF fre- pass directly through to the a carrier frequency of 14,300 MHz, as AM signal's upper and lower sidebands will extend from 14,297 to 14,303 MHz. quency, the image might high -gain IF amplifiers and

dB ics and intermodulation 21F I, -I -6 dB BANDWIDTH products that show up as "birdies" or other types of interference on the receiver. Strong local signals -60 dB BANDWIDTH can take a lot of the receiver's dynamic range, it and thereby make harder IF to hear weak signals. (RF - LO) Two forms of front -end frequency selection are typically found. A designer f4 fZ tC 3 LO RF might choose to use only -6 dB BW SHAPE FACTOR - one of them in a design. Fig. 3. An image is a response -60 dB BW Alternatively, both might be to a signal that is located the Fig. 4. The shape factor is determined by measuring the ratio of used in the design, but sep- same distance away from the the bandwidths at the -6 dB and -60 dB points. arately (i.e. the operator desired signal, but on the the local selects the type used). Or opposite side of well fall within the pass - be heard in the receiver oscillator frequency. finally, both might be used band of most front -end output. together. Those forms can tuning schemes. For exam- be called the resonant-fre- sections; one section tunes ple, at 25 MHz, a 455 -kHz IF IF BANDWIDTH quency- filter and band - the LO and the other sec- could produce images at Most of the selectivity of pass- filter approaches. tion tunes the tracking RF 24.55 MHz and 25.455 MHz. the receiver is provided by The resonant- frequency- input. A 1 -MHz bandpass filter the filtering in the IF- ampli- filter approach uses L -C el- The other approach uses would scarcely affect that fier section. The filtering ements tuned to the a bandpass filter to admit problem. However, if the first might be L -C filters (es- desired frequency to select only a portion of the RF IF frequency is 9 MHz or 50 pecially if the principal IF is which RF signals reach the spectrum into the front -end. MHz (as it is in many mod- a low frequency, like 50 mixer. In some receivers, For example, a shortwave em shortwave receivers), kHz), a ceramic resonator, a those L -C elements are de- receiver that is designed to then the images would be crystal filter, or a mechan- signed to track with the take the HF spectrum in 1- far enough removed from ical filter. Of those, the local oscillator (LO) that sets MHz hunks could have an the RF signal that a 1 -MHz mechanical filter is usually the operating frequency. array of RF input bandpass bandpass front -end design regarded as best, with the That's why you see two -sec- filters that are each 1 MHz would work well. crystal filter and ceramic tion variable capacitors for wide (for example, 7-8 The 1st -IF rejection specifi- resonator coming in next. AM- broadcast receivers MHz). cation refers to how well a The bandwidth is ex- with Iwo different capaci- In addition to the reasons receiver rejects radio sig- pressed in kilohertz, and is tance ranges for the two cited above, front -end se- nals operating on the (Continued on page 90) 85

www.americanradiohistory.comAmericanRadioHistory.Com SCANNER SCENE

By Marc Saxon Widen America Corpo- med to alert its user with ners often write requesting ration tells us that their audible and visual alarms frequency information so new BearTracker 8CT-7 announcing the presence they can tune in as the scanner is the most com- of any mobile extenders sleek FA-18 aircraft go plete highway- information within a three -mile radius. through their paces. Up In The Air system available. If it isn't, it One might then assume Thanks to Ron Bruckman, must be pretty close to the that there's a possibility that of the Radio Monitors News- top of the list. the vehicle is heading to- letter of Maryland, we have ward a speed -clocking the following current (and area. confirmed) frequencies More than that, the BCT-7 used by the Blue Angels. is also preprogrammed Even better, Ron has fur- with a complete frequency nished wed MUTE LOCKOUT frequencies for the list of highway -patrol, local - other military demonstra- !. .'. FIRE/NEWS WX /PVT 95s..0iú'LiiJ police, Department of tion teams. HOLE A SACK T LOCKOUT 0MO fl-ASK Now you can

$_-STATE HIGHWAY POL/DOT Transportation, and get in on all the action. weather channels. Literally The U.S. Navy Blue Angels' thousands of frequencies lead pilot uses 238.15 MHz. are stored in a state -by- Air coordination at show state matrix. All U.S. and sites is on 123.4, 142.00, Canadian weather chan- 143.00, and 241.4 MHz. nels can be scanned. Show -site frequencies in- Uniden's BearTracker BCT-7 "highway- infornuuion- .9slem The BCT-7 is also a full - clude 250.8, 251.6, 275.35, scanner detects and alerts the driver to the presence of any featured scanner that 360.4, 384.4, 391.9, and mobile extenders -used by state police and highway patrols-in a covers all of the standard 395.9 MHz. Other related three -mile radius. It also comes preprogrammed with thousands action bands (including the frequencies include 34.35, of highway- patrol, local- police, D.O.T, and weather channels. 800 -MHz band). It offers 100 118.1, 118.2, 121.9, 141.45, user -programmable chan- 142.025, 142.625, 143.60, Basically, the BCT-7 is a nels, and features 12 250.4, 251.4, and 394,4 MHz. "Highway- Patrol Driver- Alert- separate band- search ca- The U.S. Air Force Thun- ing Machine." The pabilities, including CB derbirds' show-site sophisticated, multiband radio and the VHF aero- frequencies are 114.95, scanner responds to trans- nautic band. One -touch 118.1, 120.45, 123.4, 123.45, missions from what Uniden band -search includes 124.925, 138.875, 141.85, describes only as "special weather-scan, news, police, 148.552, 236.55, 236.6, secondary radios installed fire, and more. 241.4, 241.6, 250.85, 273.5, on most highway patrol ve- You can get a look at the 283.5, 294.7, 295.7, 322.3, hicles across the United versatile BearTracker BCT-7 322.6, 382.9, 394,0, and States." You and I know that at any of Uniden America's 413.025 MHz. Listen for such non -technical wording many dealers. ground support on 66.90 refers to mobile extenders, MHz. which are low- powered, DEMO TEAMS The U.S. Army Golden short -range mobile trans- Since 1946, millions have Nights Parachute Team uses mitters used especially by been awed by the inspiring 32.30, 42.35, 123.4, and many state police and aerial artistry of the U.S. 123.6 MHz. highway patrols. For exam- Navy's flight demonstration The Canadian Snowbirds ple, Florida Turnpike mobile squadron, the Blue Angels. operate on 227.0, 227.6, extenders use 156.18 MHz, Their name has become 236.0, 236.6, 239.4, 239.8, while the Ohio Turnpike ex- synonymous with precision. 240.5, 243.4, 245.0, 245.7, tenders are on 465.525 Those who have attended 266.3, 275.8, 283.9, 294.5, MHz. their demonstrations and 295.6, 310.8, 316.5, 322.8, 86 The BCT-7 is preprogram- seen others there with scan- and 344.5 MHz.

www.americanradiohistory.comAmericanRadioHistory.Com Readers who would like erations, airport security at a ham swapmeet. Ben want to monitor. The to obtain a sample copy of and fire, Air and National didn't say which scanner it PRO -2035 can receive the Radio Monitors Newslet- Guard, ultralights, and was, but it worked fine. Fine, nearly 200,000 different fre- ter of Maryland can obtain more. There are complete that is, except that he can't quencies, so 91 birdies one by sending $2 to Radio VHF listings of all U.S. and hear stations on 155.295 really isn't many. Many lie Monitors of Maryland, PO. Canadian ARTCC remote MHz, which is an active EMS on oddball spots, including Box 394, Hampstead, MD sites and all their frequen- channel in his area. All he frequencies that the set 21074 -0394. A one -year cies. Much more is also hears on that frequency is doesn't receive. The odds membership, which in- contained in the sixth edi- an "open carrier," although are long that you'd ever be cludes 12 newsletters, costs tion of the largest single 155.295 MHz comes in with- inconvenienced, but it does $15. source of aeronautical fre- out any problems on his happen on occasion -for quency listings. other scanner. instance, if you wanted to MONITORING DATA Air -Scan, 6th Edition can Alas, Ben has encoun- monitor a PRO -2035 birdie The updated and ex- be ordered for $18.95, plus tered a birdie. It happens in frequency such as 155.625 panded Air -Scan Guide to $5 shipping and handling the best of scanners! In MHz. It's a real police fre- Aeronautical Communica- ($6 'o Canada), from CRB order to function, all scan- quency and is used in some fions, 6th Edition has just Research Books, P O. Box 56, ners require circuits that use cities. Ben "beat" the odds come out. It is the one all - Commack, NY 11725 -0056; certain frequencies. Those with 155.295 in his particular inclusive scanner- monitor- Tel. 1- 800 -656 -0056 frequencies vary from one scanner. ing guide to VHF (1- 516 -543 -9169 in Canada, model to another, and Try backing down on the aeronautical communica- Alaska, and Hawaii). New every modern scanner has scanners squelch to see if tions facilities in the U.S. and York State residents must its own share. As an exam- you can knock out the bird- Canada. Civil and private add $2.36 tax. MasterCard ple, the sophisticated Radio ie. If the scanner has a airports, seaplane bases, and Visa are accepted. Shack PRO -2035 has no less sound squelch, try that as heliports, military fields, and than 91 birdies sprinkled well. Maybe readers can some "unlisted" landing BYE, BYE BIRDIE between 25 and 1200 MHz. suggest alternate cures that towers are listed. Frequen- Ben, from Cherry Valley, Usually, a birdie won't co- have worked for them. cies are provided for New York, writes that he incide with a particular That's all for now. See you control towers, approach/ purchased a used scanner local frequency that you next time. departure, ground control, clearance delivery, unicom, ATIS, weather, operations, Flight Service Stations, VOR, Whether you wish to save money, etc. boldly go where no guitarist has gone before or simply have fun building electronic gadgets designed for your musical pleasure, then read Electroniciii =TAR Projects for Some of the add -on guitar gadgets you can build are:

Preamplifier Headphone Amplifier Soft Distortion Effects Unit Compressor Auto -waa Waa -waa Pedal Phaser Dual Tracking Effects Distortion Unit Expander Dynamic Treble Booster Direct Injection Box Dynamic Tremelo Thin Distortion Unit you're looking for a single If and Guitar Tuner. source of VHF aeronautic is ended Anyone with some previous electronic project building experi- listings, your search ence should have no problem assembling the projects. with the 6th edition of Air - Scan Guide to Aeronautical ELECTRONICS TECHNOLOGY TODAY INC. Communications. P.O. Box 240, Massapequa Park, NY 11762 -0240

Yes, send my copy of ELECTRONIC PROJ- Please charge my E Visa CI MasterCard U.S. listings are supple- ECTS FOR GUITAR by RA Penfold to the Signature mented (as known and address at right. I am enclosing $12.95 plus $2.95 for shipping charges in USA and Can- applicable) with additional Account No. Expie. Date ada. All payments must be made in US on -site frequencies, in the funds. Sorry, no orders accepted outside of Name 30-800 -MHz range, for USA and Canada. New York State residents add local sales tax.. Allow 6 -8 weeks for Address aeronautic -related activities delivery. including airline ground op- Check enclosed. City State ZIP 87

www.americanradiohistory.comAmericanRadioHistory.Com ELECTRONICS LIBRARY

There's much more to radio - radios. The book also explains frequency scanning than listen- how to establish a professional ing to police, fire, and listening post and find scanning ambulance calls. If you know clubs and publications. It in- Tuning in to where to tune, you can also cludes a chart that lists monitor aircraft communica- hundreds of frequencies. 1,1 Ai, iltI ti!il RF tions, satellite signals, and even Tuning in to RF Scanning; 11t!11!il (tltl° Scanning the Space Shuttle. From Police to Satellite Bands This guide to the world of costs $14.95 and is published From Police scanning teaches beginners all by Tab Books Inc., Blue Ridge they need to know to get start- Summit, PA 17294 -0850; Tel. to Satellite ed, and provides experienced 1- 800 -233-1128. scanners with the information CIRCLE 98 ON FREE Bands they need to make their hobby INFORMATION CARD more interesting and exciting. It Users can design their own by Bob Kay begins with the basics: choos- MACINTOSH icons, paint their desktop with ing a scanner and an antenna, REVELATIONS: interesting patterns, have Elvis Customizing, Upgrading drop by, or have Bullwinkle the & Troubleshooting Using Moose remind them to call System 7.5 home. by Ken Maki Macintosh Revelations costs $32.95 and is published by Macintosh computers are par- John Wiley & Sons, Inc., 605 ticularly easy to use. With a Third Avenue, New York, NY simple click of the mouse, Mac 10158 -0012; Tel. 1- 800-CALL- users can play games, write WILEY. letters, enter a spreadsheet, or CIRCLE 92 ON FREE do almost anything else. But INFORMATION CARD they are also powerful machines, and this book shows WERNER VON users how to unleash that SIEMENS: Inventor power. and International With an emphasis on the un- Entrepreneur documented features of the by Wilfried Feldenkirchen Mac's latest operating platform, the book and its included CD- Although Werner Von Siemens ROM provide practical advice is best known as an inventor and valuable hints that can and pioneering electrical engi- make a System 7.5 run like a neer-he developed the electric 10. It teaches readers how to dynamo and an improved point- customize their Macs, guides er telegraph -this biography them through the upgrade pro- focuses on his life as a busi- cess, and provides nessman. Siemens was also an troubleshooting help for both entrepreneur with a broad and software and hardware. The international business vision. book also offers chapters on His firm, Siemens & Halske, networking and system enhan- built Germany's first important cements. telegraph line and then built buying and installing accesso- The CD -ROM contains more lines elsewhere in Europe and ries, and laws and regulations. than 600 -MB of System -7.5- Asia. When he later turned his The book goes on to tell you compatible software. It contains hand to electric technology, Si- how to monitor cordless tele- software for games and enter- emens was instrumental in phones and baby monitors; tainment; telecommunications; creating the conditions for the military aircraft, exercises, and fonts, graphics, and sounds; ed- advagcement of electrical tech- ground maneuvers; NASA; ucational programs; nology, helping to bring it from sports and entertainment fre- programming utilities; PowerPC the experimental stage into the 88 quencies; computers; and utilities; and BMUG information. modern electrical industry.

www.americanradiohistory.comAmericanRadioHistory.Com The book is divided into five EPROM programmers, power The Whole Spy sections. The first, "9600 supplies, custom tool kits, mea- Catalog BitsIs," shows readers how to suring tools, adhesives, data - ., -¢., A Resoune Encyclopedic, increase their basic packet communication tools and test- sie for Rrsennhen, pis, speed to Spies, and Generally 9600 bits per second. ers, heat guns, reference books, Nosy People It includes basic information on portable and bench -top digital high -speed packet, hands on storage oscilloscopes, ELF advice for getting started, and a meters, precision hand tools, review of modems that work at and breadboards. The catalog both 1200 and 9600 bps. The also offers full lines of communi- second section, "56 kBits /s and cation test equipment, static - Faster," is aimed at those who protection products, inspection equipment, soldering/desoldering systems, ozone -safe cleaners, workbenches, and cases. All products are fully gx: l .r 1l;rxs ' into a powerful room monitor. It From their earliest days, Si- guaranteed, and orders placed and Applications also offers a look at the newest had by 4 PM will be shipped by 5 emens businesses a bugs, antennas, listening -post multinational PM that same day. flair, with activities equipment, and intelligence kits nearly In spanning the globe. from around the world, and lists covering the business history of sources for buying it all -even Werner Von Siemens, this book actual KGB surveillance equip- also depicts the history of Euro- ment. industrialization, pean German The book also shows readers history, and the history of busi- how to locate and tap any tele- ness and technology. phone. It provides distribution Werner Von Siemens: Inven- schemes, details the equipment tor and International needed, and shows how to use Entrepreneur is available for want to go even faster-up to it. Photos, tips, and tricks from $19.95 in hard cover and $12.50 two megabits per second. Sec- professionals are included, as in paperback from Ohio State tion 3 is devoted to packet are tests of cellular-phone inter- Press, 180 Pressey projects, including modems, a University ceptors (including how they Hall, 1070 Road, Co- telemetry adapter, and a Carmack work, and how to follow and lumbus, OH 43210 -1002; modem interface. The fourth intercept any nearby cellular Tel. 614 -292 -6930; section covers special topics The 1995 Catalog of Products calls). Also included is software Fax: 614 -292 -2065. including the future of packet for Testing, Repairing & Assem- that turns your PC into a cellular CIRCLE 93 ON FREE radio, and Section 5 provides bling Electronic Equipment is reader, as well as sources. INFORMATION CARD references. free upon request from Contact The book explains how to Packet: Speed, More Speed, East, 335 Willow Street South, research a person's background and Applications costs $15 and North Andover, MA 01845 -5995; and finances from the comfort is published by The American Tel. 508 - 682 -2000; PACKET: SPEED, MORE of your living room, using mail Radio Relay League, 225 Main Fax: 508 - 688 -7829. SPEED, AND forwarding, warranty -card infor- APPLICATIONS Street, Newington, CT 06111; CIRCLE 85 ON FREE INFORMATION CARD mation, magazine subscrip- Tel. 203- compiled by Bob Schetgen, 666 -1541; tions, reverse directories, and Fax: 203 KU7G -665 -7531. credit information to find and CIRCLE 94 ON FREE build a dossier on anyone. It have a lot of INFORMATION CARD There been excit- THE WHOLE SPY shows how to track down a ing in developments packet CATALOG person's real property, bank ac- radio recently, if you look 1995 GENERAL by Lee Lapin counts, stocks, bonds, offshore local beyond the BBS and pack- CATALOG OF accounts, and cars. et cluster. Hams are increasing PRODUCTS FOR This 440 -page, hands -on ency- Other chapters cover Starlight high -speed clopedia "secret their speed, building TESTING, REPAIRING & of sources' night-vision technology, on -line LANs that span whole towns, ASSEMBLING provides a wealth of profession- resources, scrambling and en- weather using packet to report ELECTRONIC al secrets, tricks of the trade, cryption to protect your own conditions automatically, map- EQUIPMENT "insider" phone numbers, and personal information, high -tech from East ping positions using Global Contact cutting -edge techniques for countermeasures, and how to Positioning receivers or tracing, tracking, surveillance, find and hire a good private pages full -line LORAN -C, tracing the flow of The 144 of this and investigating anyone or detective. with hundreds messages through the packet catalog are filled anything. The Whole Spy Catalog costs new test instruments and network, and exchanging pack- of The book shows how to lo- $44.95 and is published by In- et information via meteor scatter tools for engineers, technicians, cate and bug people, using the telligence Incorporated, 2228 propagation. This book -actu- hobbyists, and managers. Qual- latest audio bugs and telephone South El Camino Real #349, a of articles from ity, brand -name products for taps. It shows where to buy ally collection San Mateo, CA 94403; Tel. electronic testing, repair, and inexpensive such publications as QST and exotic and subcar- 415-851 -3957 (1- 800 -805 -5544 QEX, and ARRL Conference assembly are featured. riers, narrow -band, and burst for credit-card orders); how of the 1995 Proceedings -shows you Highlights catalog bugs that are easy to hide and Fax: 415 -851 -5403. to find the areas that interest induce digital multimeters and almost impossible to find; and CIRCLE 86 ON FREE you. accessories, soldering tools, how to turn a $45 tape recorder INFORMATION CARD 89

www.americanradiohistory.comAmericanRadioHistory.Com VCR HAM RADIO notion of bandwidth. The Cross Reference (Continued from page 85) cited bandwidth (e.g. 2.8 kHz for SSB) does not take NOW Find the right Part into account the effects of for your VCR measured from the points strong signals that are just on the IF frequency -re- beyond those limits. Such sponse curve where gain signals can easily "punch drops off -3 dB from the through" the IF selectivity if mid -band value. That is why the IF passband "skirts" are you will sometimes see se- not steep. After all, the lectivity referred to in terms steeper they are, the closer such as "2.8 kHz between a strong signal can be with- -3 dB points." out messing up the The IF bandwidth is that receiver's operation. Thus, which must be matched to selecting a receiver with a the bandwidth of the re- shape factor as close to 1:1 ceived signal for best as possible will result in a performance. If a too -wide more usable radio. bandwidth is selected, then Some manufacturers With the the received signal will be specify the shape factor noisy, and the signal -to- based on - 50 -dB band- ISLET VCR noise ratio deteriorates. If width, rather than - 60 dB. CR055 REFERENCE too-narrow, then you might That could indicate that the experience difficulties re- receiver is being made to This 119 -page reference contains covering all of the appear a lot better than it both model and part- number cross - information that was trans- really is ... so be careful. references to include 1994 updated mitted. For example, an When comparing shape units. AM- broadcast -band radio factors, make sure that you VCR's are made in a few factories signal has audio compo- are comparing apples and from which hundreds of different nents to 5 kHz, so the signal apples, not apples and brand names and model numbers occupies up to 10 kHz of oranges. identify changed iden- cosmetically- spectrum space (fc ± 5 tical and near -identical manufactured kHz). If a 2.8 -kHz SSB IF filter is MORE ON THE SW units. Interchangeable parts are very selected, the audio will RECEIVER common. An exact replacement part may be available only a few minutes tend to sound "mushy" and Following the offer of a away from you even though the distorted. schematic for the AAVSO- manufacturer supplier is out -of- stock. Solar Division VLF SID re-

You may be able to cannibalize scrap IF PASSBAND SHAPE ceiver I made a few months units at no cost! FACTOR ago (Popular Electronics,

The ISCET VCR Cross Reference The shape factor is a February, 1995), I received is pre -punched for standard loose - measure of the steepness and filled more than 80 IF leaf binding. . .$38.00 plus $3.00 for of the receiver's pass - requests. Since then, the shipping for each Reference. band, and is taken by Chairman of the AAVSO -SD, measuring the ratio of the Peter O. Taylor, contacted Claggk Inc. bandwidth at -6 dB to the me and informed me that VCR CROSS REFERENCE OFFER bandwidth at 60 dB (see they have a new receiver P.O. Box 4099 - Farmingdale, New York 11735 -0793 Fig. 4). The general rule is design based on the op- Name that the closer those num- amp gyrator circuit. That

Business bers are to each other, the new SID receiver does not Address better the receiver. Any- require the hard -to -find in- City thing in the 1:1.5 to 1:1.9 ductances needed by the

State Zip range can be considered older design. Pete offers in-

Phone high quality, while anything formation on the gyrator SID Enclose $38.00 for the Fifth Edition of the ISCET worse than 1:3 is not worth receiver to anyone sending VCR Cross Reference and $3.00 for shipping for each looking at for "serious" use. him a business -sized ( Reference. #10) The total amount of my order is $ If the numbers are between self -addressed envelope Check enclosed -do not send cash. or please charge my credit card. 1:1.9 and 1:3, then the re- with 32 -cents postage affix- Visa MasterCard Exp. Date /_/ ceiver could be regarded ed. If you are interested in Card No. as being middling, but getting that information, his Signature useful. address is: 4523 Thurston New York State residents must add applicable local sales tax to total. US funds only. Use US bank check The importance of shape Lane, #5, Madison, WI, 90 L or International Money Order. CB02 J factor is that it modifies the 53711 -4738.

www.americanradiohistory.comAmericanRadioHistory.Com GET THE LATEST ADVANCES IN ELECTRONICS SUBSCRIBE TO-

M PANE4METER FACES WITN YOUR PC

Mneoes Elec on R Elscumica ENJOY THE WORLD OF ELECTRONICS EACH MONTH! Budd This Subscribe to the best informed electronics maga- laser zine -the one that brings you the latest high -tech and create construction projects, feature articles on new tech- dazzling displays Show nology, practical troubleshooting techniques, circuit Pm Thal Phone On Hold design fundamentals, and much more. hrom anywáere in IM house

Now In work wit Electronics Now looks to the future and shows you Oft -Line Rep g what new video, audio and computer products are on In your npel br the horizon. You'll find helpful, monthly departments low-power Voltage Converter such as Video News, Equipment Reports, Hardware circulls Mr experimenters & Hacker, Audio Update, Drawing Board. Computer 9olla a Products, more. All designed to Telephone Meter Connections, New and and hap InIeIN8eo1 mask of give you instruction, tips, and fun. your phi cools Electronics Now gives you

exciting articles like: A 0 Electr°01f roU1 Sc Buyer's Guide to Digital Oscilloscopes sgäT he {L1.ò Build A Scanner Converter A Single -Chip Voice Recorder Pró1wnlor .. Yor Car nam ° Build A MIDI Interface for your PC Troubleshoot Microprocessor Circuits Remote Build A High -Power Amplifier for 1N your Car Add Music On Hold to your Phone ro All About Binaural Recording ,: VGA -to -NTSC Converter

FOR FAST SERVICE CALL OUR TOLL -FREE NUMBER! 1- 800 - 999 -7139 CD DON'T DELAY SUBSCRIBE TODAY! If you prefer, just fill out the order card in this magazine and mail it in today. 91

www.americanradiohistory.comAmericanRadioHistory.Com followed BUILD A SUBWOOFER by the crossover frequencies using that software, which has a list they work with: use a 10 -mH inductor price $39 (Continued from page 45) of (street prices are, of for an 80 -Hz crossover frequency; án course, lower). 8 -mH inductor for 100 Hz; a 7 -mH in- The Windows software is very easy driver is tightly fastened down to the ductor for 125 Hz; and a 6 -mH inductor to use. Several sample images are in- surface. If necessary, use a little silicon for 150 Hz, Those inductors can be ob- cluded; you simply open them as you sealer, or putty, to make sure the tained from the source given in the would any other file. Then you select mounting is really airtight. Parts and Materials list; prices vary "Render" from a menu that transforms Of course, the type of finishing from about $10 to $15 each. the image. Special adjustments can chosen for the Subwoofer cabinet is Figure 3 shows a wiring suggestion be made, if necessary or desired, for at the discretion of the individual for the inductor. The distance be- such things as coarseness, depth, builder. Here are a few of suggestions tween the inductor and the woofer is color, and so on. that you might want to consider: Foil - not important, so the coil can be lo- An image can be imported and backed wood veneer is available at cated outside of the speaker cabinet, instantly turned into a Single Image cabinet shops and some lumber -sup- or if you know ahead of time just what Random Dot Stereogram (SIRDS) that ply houses. Those might require a spe- value you want, then it could be hides the image in a field of small cial adhesive, so check with the mounted inside. However, if it is squares or circles. Or a separate pat- person who sells you the veneer for mounted inside the enclosure, make tern or image can be used to disguise the right product to use. Also, applying sure it is very firmly secured to one of the hidden image in a Single Image the veneer will require a very smooth, the cabinet surfaces with glue or sil- Stereogram (SIS), rather than just ap- clean surface, so be sure and sand off icon sealer so that it doesn't rattle. pearing as dots or squares. Stereolu- or fill -in any ridges or uneven edges After installing the inductor and wiring sions comes with several sample on the cabinet's walls. the Subwoofer to the terminals of your images and patterns that can be su- As was mentioned, painting the en- amplifier, along with the other speak- perimposed on other included im- closure is also a possibility. After sand- ers, you are finally ready to enjoy ages, or on ones you import or make ing and priming the cabinet's some first -class bass! on your own. The possibilities are end- surfaces, use a good grade of house less, and the ease with which the soft- paint. It fills small surface imperfec- ware works makes it very encourag- tions easily, dries quickly, and can be RANDOM DOT IMAGES ing to keep trying new possibilities selected to match any room interior. (Continued from page 50) that stretch the imagination. The rendered images appear on- Wiring and Testing the System. screen in the colors that they are cre- Before you try out your system, you ages. N.E. Thing Enterprises (19C ated. The beauty of Windows is that should arrange some kind of Crosby Drive, Bedford, MA 01730; Tel. anything can be printed easily, includ- crossover filter for it, to allow only low 617- 275 -6960) carries a full line of ing the 3D images. And if you are for- frequencies to go to the Subwoofer. clothing, calendars, posters, post tunate enough to have a color printer, Here are the values of inductor coils cards, puzzles, software, and more, all you can print the images in color as that can be used as low -pass filters, in full color. All kinds of three- dimen- they appear on your computer sional images and illusions are fea- screen. When printed on a black -only tured. But there's also another way to printer, a few of the SIS images lose get your hands -or eyes-on some of some of their effect. But the SIRDS im- these images: You can make your ages, which appear as multi -colored own on your personal computer. We speckled patterns on- screen, don't took a look at Stereolusions, which is lose any of their visual effect when just one of the several software pack- printed in black and white, as you can ages available that let you have fun see from the ones that are presented with 3 -D images. in this article. The worst thing about these 3D im- Stereolusions. The Windows en- ages is that a lot of people don't be- vironment has become a great place lieve they are there, and think they are to work with images. With all the soft- being made fools of. But for people ware that lets you create and manip- who can see them, there's nothing like ulate graphic images, it's the perfect making your own. Making these im- place to create an image that you ages is just one more thing that a per- want turned into a 3D image. Ster- sonal computer makes short, and eolusions from I/O Software (10970 entertaining, work of. Cucamonga, CA 91730; Tel. 909 -483 -5700) lets you import any image in the Windows Bitmap (BMP) or Windows Metafile (WMF) format and BUY This bottom view shows the placement of turn it into a Stereolusion. The images BONDS 92 the woofer and the vent. pictured in this article were created

www.americanradiohistory.comAmericanRadioHistory.Com these theories? Let's see if we can by DESIGNING CROSSOVERS SPEAKER CABLES limiting our discussions to those with at (Continued from page 42) (Continued from page 48) least some backing in reality: Wire Metal Crystals: Back in 1980, Now, using the program will require lowest dielectric constant possible A. J. van den Hul did some research on some exact knowledge of just what should ideally be used in its design: the electrical behavior of speaker ca- the sonic problem is: With a test tape Table 3 is a listing of the standard di- bles. Using a spectrum analyzer, he or oscillator and a sound -level meter, electric constants for most of the discovered that "good- sounding" ca- take a series of readings to determine common speaker -cable insulating bles seemed to have one charac- just what the frequency range of the materials. Note that the values of teristic in common: they produced a peak is. See Fig. 6 for an example of those materials do not vary by much. "regular set of harmonics" starting the type of measurement to be above 500 Hz. He then went on to made. Once that is done, answer the attribute that to an effect of the crystal TABLE 3 program prompts with the required structure of the wire, and developed a information and it will calculate the Material Dielectric Constant wire -manufacturing process to dupli- necessary component values for a (At 1 kHz) cate the effect. trap filter (see Fig. 7). Inserting that cir- Polyethylene 2.26 Pure -Metal Conductors: Research cuit as part of the speaker's crossover by some cable manufacturers sug- Nylon 3.5 and compensation network should gests that very pure metals (specifi- have the desired effect, but.it is always Vinyl Chloride/ cally copper) make a more perfect good to go back and check because Vinyl Acetate conductor. From that, the use of very (Polymer) 3.15 the other networks in the system might pure copper (more than 99.99%), oxy- affect the filter's action a little, in which Polypropylene 2.25 gen -free copper, and long -grain case, some trial- and -error work with Teflon 2.1 copper, is presumed to make a no- other component values might be re- ticeable difference. Based on that, a quired to make things work just right. great -many manufacturers use those Also, be sure that the resistor that is Resistance and Capacitance. Now materials in their products. used in the filter has an adequate that we have reviewed several cable Litz Wire Cables: Some years ago, power rating -at least 10 watts or so. designs, you might have noticed just when the first special -purpose audio how many factors determine the resis- cables were being developed, insu- Putting it all Together. The complex tance and capacitance of the ca- lated, fine, stranded wire woven in a network of circuits with varying com- bles. That results in there being a braid was thought to be very good. ponent values that we have just cal- range of resistance and capacitance That was a form of what is commonly culated might seem confusing to a values for currently produced speaker called Litz wire. Typically it is used home experimenter. Where do all the cables. The minimum resistance value where extreme flexibility is important,

pieces fit in relation to each other; is less than 1 milliohm per foot, and the like in headphone cable wiring. The can we just put them anywhere, in any maximum value is about 50 milliohms problem with those early cables was circuit arrangement? In this case, the per foot. The minimum capacitance that the two conductors' wires were all answer is no. To work correctly, they value is about 5 pF per foot, and the braided together in one piece, mak- must be assembled in a particular se- maximum is about 160 pF per foot. ing the inductance extremely low, but quence in the overall circuit. Note that the resistance values the capacitance extremely high! Figure 8 shows, in block- diagram have an upper to lower value spread Many amplifiers dian't "like" that form, the wiring sequence that should of about 50 to 1. Also, the capaci- much capacitance, and blew fuses or be used. Here is that sequence in tance values have a spread of about activated their protection circuitry. order, along with the programs used 30 to 1. Most manufacturers don't give Stranded -Wire Noise: Some man- to determine the component values: inductance values, so none were ufacturers have claimed that in 1. The crossover network, 2- or 3 -way available to make a comparison. That stranded but uninsulated wiring bun- as needed -XDES -2.BAS or is not unreasonable, because it is re- dles, a small amount of "noise" is gen- XDES- 3.BAS. sistance and capacitance that are erated by the wire current crossing 2. The trap filter, as needed -TRAP- the most critical parameters. back and forth from strand to strand FIL.BAS. as it moves down the length of the 3. The attenuation circuit, as Weird Science? Anyone who keeps cable. For that reason, some man- needed -DRIVE RAT. BAS. up with all the happenings in the au- ufacturers use wire where each strand 4. The Zobel impedance- compensa- dio world knows that from time to time is individually insulated from the next. tion circuit, as needed -ZOBEL.BAS. there are claims made of unex- Metal -Alloy Wire Materials: This is Note: All circuits are independent of plained physical processes, es- a relatively new development, and each other, and any can be deleted pecially when it comes to cables and only a few commercial cables of that anywhere in the network without sig- wire. In many cases, though, only a type exist. Companies using alloys in nificantly changing the performance few people have been able to "hear" their cables are not saying too much of the other circuits, as long as the the results of those phenomenon. at this time, other than that some of sequence of those remaining are as Is it possible to sort through (and the alloys are a hybrid of a certain shown in Fig. 8. avoid) some of the more suspect of metal and carbon. 93

www.americanradiohistory.comAmericanRadioHistory.Com November 20, 1950. A furious COLOR TV David TELEPHONE TESTER Sarnoff directed RCA's legal staff to file (Continued from page 59) (Continued from page 62) suit to reverse the FCC's directive. The legal challenge ultimately reached beam of electrons, the second dot the Supreme Court where the FCC's Checkout and Use. To test the trans- emitted green light, and the third ruling was upheld. mitter and receiver, connect a bat- emitted blue light. Those three pri- CBS was then forced to begin color tery to the transmitter. Then attach the mary colors of light could be com- broadcasting despite the fact that vir- pairs of alligator clips on one of the bined to produce any desired color. tually no one owned a CBS color re- units to the corresponding pairs on Three separate electron guns di- ceiver. The incompatible broadcasts the other unit. Make sure that the rected beams toward the phosphors caused video "garbage" on mono- proper colors are connected and the through a metallic grid of tiny holes chrome sets. CBS rapidly lost viewers pairs are matched. The LEDs on both located only one -half inch from the and sponsors. Fortunately for CBS, the units should glow green. If some or all phosphor screen. The holes were ar- government suspended the man- of the tri -color LEDs on the receiver ranged so that only the electrons from ufacture of color -television equip- glow red, something has been wired the red gun could strike the red -emit- ment late in 1951 so that manufac- backwards (possibly the LEDs them- ting phosphor dots, the beam from turers could direct their efforts toward selves). If an LED on either unit doesn't the green gun could strike only the aiding the Korean War effort. That al- glow, check for a poor connection. green -emitting dots, and the beam lowed CBS to stop color telecasting. Once you have verified proper op- from the blue gun could strike only the eration of the clips on the units, check blue- emitting dots. The three -gun RCA Vindicated. An ad hoc sub- the modular jacks of the transmitter shadow-mask picture tube is illus- committee of the NTSC had been es- and receiver using a patch cable. If trated in Fig. 2. tablished in November, 1950 to review the patch cable you are using has The demonstrations by RCA of its the state of the art as it existed with reversed the voice pair or pairs, the tri- shadow-mask picture tubes (a single - respect to color television. Clearly, color LEDs will glow red. If you are test- gun prototype had also been de- most of the industry had not been ing the 6- position, 6- contact jack, the veloped) went well. The RCA color - pleased with the FCC's decision to en- third voice pair might not be present television system still had a few "rough dorse the CBS system. After many in your patch cable and the LEDs for edges" but improvements and modi- months of discussion, the subcommit- that voice pair won't glow. fications were being made almost tee's report recommended establish- In addition to being used with the daily. Because of that, RCA could not ing a totally electronic and compati- transmitter, the receiver can be used provide the FCC with exact numerical ble color -television system that was on its own to test "live" voice pairs. recommendations for the "standards" remarkably similar to the one RCA When the receiver is connected di- that would have to be established if its had been proposing. rectly to a live, standard telephone system were to be adopted by the The result of that report was the line (using the modular cord, alligator industry. creation of what became known as clips, etc.) the proper LEDs should the "Second NTSC" to conduct addi- glow. Red indicates that the respec- The First Standard. The color -tele- tional tests of and establish complete tive voice pair is polarity- reversed, vision hearings ended in May, 1950 standards for the system proposed by green means its polarity is correct, no after eight months of testimony and the subcommittee. Field tests and sys- glow means the circuit is dead, and demonstrations. Over 9700 pages of tem modifications would take place orange means that there is AC on the testimony had been taken from 53 for approximately two years. line (if you get that indication you witnesses. The FCC issued its "First Re- On July 21, 1953, the NTSC filed a should determine where it is coming port of the Commission on Color Tele- petition with the FCC proposing the from and have the problem cor- vision Issues" on September 1st. adoption of the color -television stan- rected immediately). It was obvious in the "First Report" dards we know today. To his credit, Please note that the test just de- that the FCC had relatively little con- Peter Goldmark of CBS took a lead scribed should not be done on multi- cern about the issue of compatibility part in recommending the adoption line key- system wiring. If the system in with existing receivers despite the fact of those standards. The FCC adopted question is a multi -line telephone unit that now some 8- million mono- the NTSC- recommended standards (especially with more than two lines) chrome television sets were in use. The on December 17, 1953. While those the modular cable and jack might television industry was told that it had color television standards were not es- only appear to be standard tele- only three months to demonstrate a tablished solely from RCA's efforts, phone jacks. Those systems usually color system superior to CBS' field -se- they did follow directly from RCA's have digital signals -not telephone quential system. work to achieve "all electronic com- lines -that are carried on one or Despite the formal protests by RCA patible color television." The fact that more of the pairs. If you use the Tester and most other manufacturers (with those same standards remain in use in on one of those you might damage the obvious exception of CBS), the the U.S. today attests to the job done the telephone, the telephone system, Commission soon issued its "Second by the television engineers and the or both. For those systems, the Tele- Report on Color Television." In that re- NTSC at that time. Indeed, David Sar- phone- Wiring Tester should be used to port, the CBS system was established noff now was able to have the "last test cables only after they have been 94 as the industry standard effective laugh." disconnected at both ends.

www.americanradiohistory.comAmericanRadioHistory.Com Supplement to Popular Electronics Popular Electronics altJuly 1995 r 1 Paperback Books GREAT BOOKS AT BUDGET PRICES

100 RADIO HOOKUPS ,41 iXPERIMENTERI IIMRRRY NO 7 INTERNATIONAL RADIO _re"-:;`-:. International -#7 -$3.00 l! STATIONS GUIDE -BP255 Radio Stations AA -$9.95 First published in May, 1923 this Guide popular booklet went into reprint Provides the casual listener, editions nine times. It is packed amateur radio DXer and the with circuits, theory, antenna professional radio monitor with an ' t'hCt t M'"! EMAN installation and tips on consumer essential reference work designed

: r radio receivers that were popular in _ as a guide for listening tothe the early 1920's. Antique radio buffs complex radio bands. Includes and those inquisitive about the early coverage on Listening to Shortwave days of radio will find this booklet Radio, ITU Country Codes, an exciting, invaluable and excellent 2 EDITION Worldwide Radio Stations, reference into the minds of early - REVISED European Long Wave and Medium day radio listeners. Sorry, we Wave Stations, Broadcasts in THE I. CO cannot honor the original 25 -cent E. English and more. cover price.

HOW TO USE OP AMPS i WIRELESS & How to Use -BP88 -$5.95 ELECTRICAL CYCLOPEDIA Op Amps -ET T1 -$5.75 The engineer's best friend is the op amp. This basic building block is A slice of history. This early found in many circuits, analog and electronics catalog was issued in digital alike. The op amp finds many 1918. 't consists of 176 pages that useful purposes such as: document the early history of oscillators, inverters, isolators, electricity, radio and electronics. It high- and low- filters, notch and was the "bible" of the electrical band -pass filters, noise generator, experimenter of the period. Take a power supplies, audio, MIDI, and look a4 history and see how far we much more. Prepared as a have come. And by the way, don't designer's guide, some limited math try to order any of the radio parts is used, however engineers and and receivers shown, it's very hobbyists alike find it a useful text unlikely that it will be available. for their design needs.

ELECTRONIC TECHNOLOGY TODAY INC. SHIPPING CHARGES IN SORRY No orders accepted Number of books ordered USA AND CANADA P.O. BOX 240, Massapequa. NY 11762 -0240 outside of USA & Canada $0.01 to $5.00 $2.00 $5.01 to $10.00 $3.00 Total price of merchandise S Name $10.01 to 20.00 $4.00 Shipping (see chart) S Subtotal S Address $20.01 to 30.00 $5.00 $30.01 to 40.00 $6.00 Sales Tax (NYS only) 5 S City State Zip $40.01 to 50.00 $7.00 Total Enclosed $50.01 and above $8.50 All payments must be in U.S. funds! ET01 IL

www.americanradiohistory.comAmericanRadioHistory.Com ALFAELECTRONICS -.,1',:Q,1,1 DMM 89 $199.95 DMM 2360 DMM 20 Fluke Multimeter Most Advanced DMM $119.95 Fluke 12 $84.95 $74.95 Holster C -10 $10 All Purpose & Communication Inductance: 1µH -40H DMM +LCR Meter II Capacitance: 1 Fluke 70 $67.5 -80.7 to 81.4 dBm with 40 -1200O pF-20µF Very Versatile Frequency 1 Hz -20MHz Fluke 73 II $94 20 reference impedances DMM Volt, amp, ohm, diode, Fluke 75 II $129 True RMS Inductance: 1p1-4-40H 20 Amp AC/DC current Frequency counter. 0.01 Hz -10MHz Capacitance. 1 pF -40uF Transistor HFE Holster C -70 $16 Capacitance: 1 pF- 50,000µF Frequency: 1 Hz - 4MH6 Continuity, duty % Fluke 77 II $149 Temperature: -40-302 F hold /Max Measure AC volt to 20kHz Peak Fluke 79 II $169 5000 counts, 0.1% accuracy TTL Logic Test 20MHz Ruggerdized case Fluke 29 II $169 Auto/manual range, fast bar graph Diode, Continuity Rubber holster $8.00 Min/Max/Ave/DH /Relative/Zoo m Volt, Amp, Ohm Fluke 83 $225 Auto power off 3999 count display Full line of DA/Ms, .. economy, compact, Fluke 85 $259 Input warning Peak Hold AI ,MmCdl`.. Vfi ruggerdized, solar cell, Fluke 87 $287 Splash proof Auto power off automotive, heavy Volt, amp, ohm, logic, diode, continuity Ruggerdized case. duty, industrial Fluke 97 Temperature Pote rdrdad starts from $15.95 Ruggerdized case C.`, PlIOCTIMETE. Scope Meter$1785 Rubber holster included Rubber Holster $8.00 LCR Meter 131D LCR Meter 814 Frequency Counter $229.95 $189.95 FC -1200 $129.95 j Most Advanced LCR Frequency 0.1 Hz -1 25GHz Best Resolution LCR Display. 8 digit LCD I Dual display UQ or C/D Period 0.1 -0 is I Inductance: 0.1µH -1000H Inductance: 0.1µH -200H Capacitance: 0.1 pF- 20,000µF Records Max/Min /Average Capacitance: 0.1pF- 10,000µF Data hold, relative mode Resistance: 1 mt0 -20Mí1 Impedance:1 mQ -1OMC1 Telescoping antenna $8.00 0.7% basic accuracy 1% basic accuracy Deluxe case $5.00 Auto/manual range Dissipation factor indicates leakage Also Available: Dissipation factor & O factor in capacitor and Q factor in inductor AC /DC clamp meter,Light meter, Serial & parallel mode Zero adjustment to reduce parasitics Thermometer, pH meter High Relative mode for comparison Best for high frequency RF voltage probe, Digital caliper, and to remove parasitics SMD and chip component test probe Anemometer Electronic scale, Statistics, tolerance, 525.00 gauge,Tachometer Force& Best for design, incoming Stroboscope, Humidity EMF LIMITED QUANTITY SPECIAL adapter, Sound level meter, testing & production DIGITAL LCR METER $74.96 Frequency counter, SWR/field SMD and chip component strength /power meter, Dip meter test probe $25.00 0.1pF, 101, 1OmQ resolution 20 MHz Oscilloscope with Delay Digital Storage Scope Sweep PS -205 $429.95 DS-203 20MHz, 10M Sample/sec $729.96 Dual Trace, Component test, 6" CRT, X -Y Operation, TV DS-303 30MHz, 20M Sample/sec $849.96 Sync, Z- Modulation, CH2 Output, Graticule Ilium, 2 probes each has x1,x10 switch. Best price with delay sweep. DS-303P with RS-232 Interface $1,049.96

{ PS-200 20 MHz DUAL TRACE $339.95 Switchable between digital and analog modes a PS-400 40 MHz DUAL TRACE $494.95 2 K word per channel storage PS-405 40 MHz DELAY SWEEP $569.95 8 bit vertical resolution (25 Lerel /div) PS -605 60 MHz DELAY SWEEP $769.95 Expanded Timebase lUms/div - 0.5 s/div Scope Probe:60MHz x1, x10 815, 100MHz x1, x10 $22 Refresh, Roll, Save all Save CH2, Pre-Trig 250MHz x1, x10 $29, 250MHz x100 $39 Plotter control DC Power Supply DC Power Supply Triple Output PS-303 $159.00 PS-8202 $499.95 VDC , 0-30 0-3A output Two 0-30 VDC , 0-3A outputs constant voltage 8 constant curent mode 1111Lm One fixed 5VDC, 3A output 0.02% r 2mV trie regulation 1E31 Capable of independent or tracking operation 0.02% + 3mV load regulation Constant voltage and constant current mode 1 rnVrms noise and ripple Four digital meters for volt and current display Short drain and overload protected Excelent regulation and low ripple PS -8200 with digtal voltmeter $179 00 :to to,. Short circuit and overload protected Also available: 30V/5A, 60V/3A, 60V/5A Also available: 30V/5A triple output $549 95 16V/10A, 30V /10A Dual tracking 30V/3A, 30V/5A, 60V/3A, 60V5A RF SIGNAL AUDIO GENERATOR FUNCTION GENERATOR GENERATOR AG-2601A $119.00 FG -2100A $169.95 0.2 Hz -2 MHz in 7 ranges SG-4160B $119.00 10Hz - 1MHz in 5 ranges Output0 -8Vrms sinewave Sine, square, triangle, pulse and ramp 100 kHz- 150MHz sinewave in 6 0- 10Vp -p squarewave Output 5mV- 2OVp -p ranges Synchronization. +3% of oscillation 1% distortion, DC offset + 10V RF Output 100mVrms to 35 MHz frequency per Vrms VCF: 0 -10V control frequency to 1000:1 Internal 1 kHz, External 50Hz -20kHz Output distortion. AM modulation FUNCTION GEN /COUNTER 0.05% 500Hz - 50kHz Audio output 1 kHz, I Vrms 0.5 % 50Hz - 500kHz FG-2102AD $229.95 Output impedance: 600 ohm Generates signal same as FG -2100A Frequency counter 4 digits RF SIGNAL AUDIO Feature TTL and CMOS output GEN. /COUNTER GEN. /COUNTER SWEEP FUNCTION SG -4162 AD $229.95 AG- 2603AD $229.95 GEN. /COUNTER $329.95 0.5Hz to 5 MHz in 7 ranges Generates RF signal same as Generates audio signal same as Sweep: Linear 10:1 /Log 10.1 20ms to 2s SG -4160B AG-2601A AM Modulation 6 digit frequency counter 1Hz - 150 6 digit frequency counter 1Hz- Gated Burst, Voltage Control Generato- MHz for internal and external 150MHz for internal and external rc[pUrwcv Generator Control Voltage & 8 digit counter source Sensitivity <50mV sources Sensitivity <50mV 1Hz-10MHz for internal & external sources ALFAELECTRONICS (800) 526- 2532/(609) 520 -2002 15 DAY MONEY BACK GUARANTEE .1 YEAR WARRANTY FAX:(609) 520 -2007 CALL OR WRITE FOR FREE CATALOG AND BEST OFFER. 741 Alexander Rd., Princeton, NJ 08540 96 Visa, Master Card. American Express, COD, Purchase Order Welcome

CIRCLE 26 ON FREE INFORMATION CARD

www.americanradiohistory.comAmericanRadioHistory.Com Are Cable Companies Sucking You Dry?

Take a Bite out of High Rental Fees with your own Converters & Descramblers

Everquest Panasonic Jerrold Zenith Pioneer Scientific Atlanta Oak Eagle Hamlin Tocom

E.t.,Ce.] ToOlrFerree 1 800 624 -1150 MDCall today for a FREE catalog!

Member of NaG nal Consumer National Consumer S. Omaha, NE 68114 72 Street Association 875 Cable Cable Association 97

www.americanradiohistory.comAmericanRadioHistory.Com CALL TOLL FREE 1- 800 -292 -7711 C & S SALES WRITE FOR 1- 800- 445 -3201 (Can) EXCELLENCE IN SERVICE FREE CATALOG Line Tracker Dual- Display Electronic Tool Kit Model TK -1000 MV-963 LCR Meter A professional organizer tool kit at affordable prices. No yg9n $52.95 w/ Stat Functions student should be without this unique tool kit that holds all the tools you need. (Infra -red Sensor) # B +K Model 878 Including: The robot follows a $39.95 $239.95 Diagonal Cutter a black line - Auto /manual range Long Nose Pliers on white paper ,,- Many features 6" Wire Stripper Preassembled PCB with Q factor Solder 60/40

High Accuracy 6" Screwdriver i I 6" Phillips Driver .i

Robotic Arm Stereo Cassette Player Safety Goggles t Y -01 Kit IC Puller $49.95 ÿ Model 3pc Nut Drivers Q ú -_ - Iron 25W gin% n (Wired Control) TR -18K Stand } Movement grabs ..+. $16.95 Solder Wick ` & releases, Headphones Desoldering Pump lifts & lowers, Included 5 pc Solder Ease Kit pivots from side to side ` "" 6.c Precision Screwdrivers Digital Elenco Digital Digital Function Generator LdElpgi Multimeter LCR +OMM Capacitance LCR Meter GF -8026 - EDM -83B LCM-1950 Meter LCR -680 r. $239 $175.00 $79 CM -1555 I $79.95 Almost every 12 Functions Int/Ext $49.95 3 -2v DlDigit feature Freq to 4MHz available =- Measures capacitors LCD Display Operation Bargain of Inductance Sine, Square, Triangle, Pulse from .1 pf to 20,000µf Inductance the decade Capacitance Ramp, to 2MHz, Freq Ctr 1 uH to 20MG i 3 -3/4 Digit Multimeter Digital Frequency Counter Fluke Multimeters BK -390 Multimeter Kit F -1225 (All Models Available Call) vnn ' $ 139.00 w/ Training Course << = - $225.00 - Scopemeters 70 Series = 0.1% DCV accy ,'" `- M -2665K iv, if É Model 97 $1,795 . 8 Digit LED display Model 7011 $69.95 Analog bar graph *. Wide meas range 10 Series Model 7311 $97.50 9 Auto /manual ranging $49.95 r High sensitivity Model 10 $62.95 Model 7711 $149 Capacitance meas - .;:,. Full function 34 ranges Data hold function Model 12 $84.95 Model 7911 $175 _? Temperature probe =n Ideal school project Input impedance 1 Mf or 50c 20 Series 80 Series M -2661 (Assembled) $55.00 10:1 input attenuation function Model 2911 $175 Model 87 $289 Triple Power Quad Power High Current DC Wide Band Supply Supply Power Supply Signal z XP -620 ` , XP -581 BK -1686 $169.95 Generators .. a By Elenco ¡ By Elenco 3 to 14 VDC Output ± . SG 9000 VA 0C 12A @ 13.8v , $75.00 i $79.95 For servicing high $124.95 3 fully regulated supplies; 1.5 -15V @ Four supplies in one unit; 2 -20V © 2.5A, power car stereos, RF Frequency 100K- 450MHz 1A, -1.5 to -15V @ 1A or 3 -30V © 1A 5V 3A, -5V @ .5A and 12V 1A. All © © camcorders, ham radios, etc. AM modulation of 1 KHz Variable & 5V @ 3A Kit XP -620K $49.95 regulated and short protected Connect 2 or more in .arallel SG -9500 150MHz $239.00 Telephone Kit Function Generator Learn to Build & Program Digital /Analog Trainer PT -223K Blox Computers with this Kit Complete Mini -Lab For Building, $14.95 #9600 Testing, Prototyping Analog and Digital By Available _* Elenco By Elenco Assembled ' $29.95 PT -223 --- _ _ in U.S.A. $15.95 Kit 828.95 ,la 1--.,, XK -525 Sine, Triangle, Square Wave 0 v 1E-I: -- .. $159.95 AM /FM Transistor Telephone Line r` iic vi+ Radio Kit Analyzer I quo with Training Course 'ii, XK -525K °' °c By Elenco Model AM /FM 108 -',.c $129.95 S o - $129.00 -- 629./F From scratch you build a complete system. Designed for school projects, with 5 built -in 1aTnsistor, 5 Diodes '% supplies. Includes a function Easy to build because Our Micro -Master trainer teaches you to power generator schematic is printed on the PCB write into RAMs, ROMs and run a 8085 with continuously variable, sine, triangular, Makes a great school project Kit 11-400K $19.95 microprocessor, which uses similar square wave forms. All power supplies are Model AM -550 AM Only $17.95 Assembled TT -400 $26.951 machine language as IBM PC. regulated and protected against shorts. WE WILL NOT BE UNDERSOLD C& 15 DAY MONEY BACK UPS SHIPPING: 48 STATES 5% S S A L E S I N C. eel GUARANTEE IL RES 7.5% TAX ($3 min $10 maxi 1245 ROSEWOOD, DEERFIELD, IL 60015 FULL FACTORY WARRANTY OTHERS CALL 7x 1 FAX: 708 -520 -0085 (708) 541 -0710 PRICES SUBJECT TO CHANGE WITHOUT NOTICE 98 CIRCLE 132 ON FREE INFORMATION CARD

www.americanradiohistory.comAmericanRadioHistory.Com FREE PROBES ELENCO HITACHI B +K WRITE FOR WITH ALL FREE SCOPES CATALOG SCOPES AT GUARANTEED LOWEST PRICES QUALITY - ELENCO OSCILLOSCOPES B+K 20MHz 2- YEAR WARRANTY 60MHz S -1360 $775 tosoommee Delayed Sweep Delayed Sweep S-1365 $849 7Itesda 212s $539.95 Cursor Readout 40MHz DUAL -TRACE

Voltage, Time 1 mV /div sensitivity Frequency differences Wt.ede1 1s41á Video sync separators displayed on CRT Z axis input Single sweep $749.95 V mode -displays 2 signals AESIMENBENSIEMEEM 40MHz unrelated in frequency 60MHz DUAL -TRACE s -1340 $495 1mV /div sensitivity 2- Channel %14dcl 2160 Sweep to 5ns/div Dual time base Signal delay line S -1345 $575 $949.95 Component tester Delayed Sweep V mode -displays 2 signals unrelated in frequency Beam Find Component Tester 100MHz THREE -TRACE

,,,,,,,, , 1 mV /div sensitivity Model 2190 Sweeps to 2ns/div 25MHz Dual time base $1,379.95 Signal delay line S -1325 $349 19kV accelaerating voltage Calibrated delay time multiplier 2- Channel 20MHz ANALOG with S-1330 $449 DIGITAL STORAGE Delayed Sweep 20MHz analog bandwidth Beam Find 20MS /s sampling rate %adld 0522.4 2k memory per channel Component Tester 20MHz equivalent $869.95 time sampling Delie«d4Gle £gsci, -oceot at / endaWe Paced.

HITACHI POPULAR SERIES Elenco DS -203 20MHz, 10MSIs FLUKE SCOPEMETERS V -212 - 20MHz, 2 Channel $425.00 Digital Storage Oscilloscope A handheld instrument that combines a V -222 - 20MHz, DC Offset $695.00 50MHz, 25MSis dual channel digital storage V -422 - 40MHz, Dual Trace $849.00 oscilloscope with feature -packed 3000 count V -522 - 50MHz, Dual Trace $975.00 digital multimeter. V -523 - 50MHz, Delayed Sweep $995.00 goad 93- $1,225 V -525 - 50MHz w/ Cursor $1,369.00 7X.edel 95 - $1,549 HITACHI COMPACT SERIES SCOPES 71tICedel 97 - $1,795 V -660 - 60MHz, Dual Trace $1,375.00 Autoset, automatically w $1,449.00 V -665A - 60MHz, DT, /cursor sets voltage, time & trigger V -1060 - 100MHz, Dual Trace $1,549.00 Multimeter display; V -1065A - 100MHz, DT, w/cursor $1,595.00 Plotter Output 2K Word Per Channel 3 -2/3 digits ( >3000 counts) V -1085 - 100MHz, QT, w /cursor $2,125.00 8 Bit Vert. Resolution 2048 Pts Hlor. True RMS volts; AC or VC -6045A - 100MHz, Digital Stor CALL $749 Resolution Much More AC +DC up to 600V VC -6025A - 50MHz, Di ital Stor CALL ' CALL TOLL FREE 15 DAY M `c' C &S SALES INC. r1 FULL FACTORY WARRANTY IL 60015 1245 ROSEWOOD, DEERFIELD. 1- 800 -292 -7711 I 1k" ALL PRODUCTS ARE FACTORY NEW 708- 520 -0085 (708) 5411 -0710 PRICE'S CHANGE WITHOUT FAX: 1- 800 -445 -3201 (Can) I 99 CIRCLE 132 ON FREE INFCRMATION CARD

www.americanradiohistory.comAmericanRadioHistory.Com OGet instant tech information FREE from your Fax or Computer! You can .11 obtain specs, freq. info, software and more from our automated services. For fax facts, call from your stand = = alone fax machine and follow the voice prompts. Use the BBS from your modem of fax/modem equipped computer. Dial 317- 849 -8683 for fax back service, or dial 317 -579 -2045 for our computer bulletin board service. Continuous Coverage Shortwave Radios COMMUNICATIONS Sangean ATS -818CS $219.95 Sangean ATS -818 $184.95 Total Coverage Radios J Sangean ATS-803A $169.95 Sangean ATS-808 $179.95 TRIDENT Sangean ATS-606 $149.95 TR 1200XLT Sangean ATS-606P $169.95 AM Broadcast to Sangean ATS -800 $89.95 Microwave 1000 Scan Three new Bearcat units offer Grundig YB400 $219.00 Channels $389.00 expanded coverage and more memory Grundig Satelit 700 $399.00 than before. The 890 offers 200 500KHz to 1300MHz coverage in a channels, base /mobile operation, VFO programmable hand held. Ten scan tuning, service search, weather alert, banks, ten search banks. Lockout on search and store, and more. The 2500 search and scan. AM plus narrow hand held has 400 channels, fast scan and broadcast FM. Priority, hold, and more. The Bearcat 8500 has 500 delay and selectable search increments. Cell channels in 20 banks, VFO, auto Lock. Permanent memory. 4 AA ni -cads and store, alpha numeric display, 10 Hand Held Scanners wall plus cig charger included along with belt priority channels, aux tape output clip, case, ant. & earphone. Size: 6 7/8 x 13/4 x jacks, and coverage to 1.3 Gigahertz. Bearcat 200XLTN 2 1/2. Wt 12 oz. Fax fact document # 205 $209.95 200 Channels 800 MHz TRIDENT Bearcat 2500XLTA hand held $349.95 Ten scan banks plus search. Covers29- Bearcat 8500XLTC mobile S389.95 54, 118 -174, 406 -512 and 806 - TR4500 $449 Bearcat 890XLTB mobile 956MHz (with 2016 Channels 3259.95 cell lock). 25- 1300MHz, 500 ch. in 8500, 400 in 2500. 890 has 200 ch & Featuresscan, search, delay, 10 1 to 1300MHz 29- 956MHz All cell locked. Features include turbo scan, VFO, search priorities, mem backup, lockout, Coinprlter Cara of and store, Priority, LCD display, and more Fax Facts474,475,476 WX search, keylock. Includes NiCad 62 Scan Banks, 16 & Chrgr. Size: 1 3/8 x 2 11/16 x 7 1/2. Search Banks, 35 Channels Mobile Scanners Bearcat 120XLTJ 100Ch H/L/U $149.95 per second. Patented Computer control for Bearcat 150XLT 100Ch H/L/U/8 $199.95 logging and spectrum display. AM, NFM, TRIDENT Bearcat 220XLTJ 200 Ch H /L/U /8 $249.95 WFM, & BFO for CW /SSB. Priority bank, TR2C Coverage of above hand helds delay /hold and selectable is: 29 -54, 136 -174, 406 -512, and search. Cell Lock Police & CB 800MHz band as indicated. Fax facts 9475 Permanent memory. DC or AC with adaptors. $69.95 Mtng Brkt & Antenna included. Size: 2 l /4H x 5 Scans police pre- Table Top Scanners 5/8W x 6 l /2D. Wt. llb. Fax fact #305 programmed by state channel plus the CB channel of your choice. Also has Mobile Bearcat 855XLTE 50 Ch w/800 $159.95 TRIDENT Repeater and Weather. Extra cost option of CB Bearcat 142XLM 10Ch H/L/U $ TR980 73.95 $279.00 and laser detectors built in. Compact size allows Bearcat 147XLJ 16 Ch H /L/U $ 89.95 126 Channels for dash or visor mounting. Mtng hardware and Bearcat 172XM 20Ch H /L/U /Air $124.95 5MHz to power connectors included. Size: 5 5/8 x 4 7/8 x Bearcat 145 16Ch H /L/U $ 79.95 999MHz 1 3/4. Wt: I.SIbs. Fax fact #580 Most Economical receiver in Bearcat 700AX 50Ch w/800 $159.95 Accessories & Etc. its class, offers AM, NFM Wide FM, Bearcat 350A 50 Ch Ií/LN $119.95 Mag Mount Mobile modes. 5KHz increments. Delay & Bearcat 560XLJ 16 Ch H/L/U S 89.95 Ant MA100 $ 19.95 Base Ant. 25- 1000MHz hold & Search. Cell Lock NiCads, chger & whip Bearcat 760XM100Ch H/LJl1/Air/800 $219.95 AS300 $ 59.95 Pre -Amp .1- 1500MHz ant. Size: 5 7/8H x 1 1 /2W x 2 D.Wt 14oz. Bearcat T2 state/state scan 5144.95 GW2 S 89.00 Wide Coverage Antenna S 119.95 Base Discone Ant DA300 $ 89.00 Winner of the 1994 INNOVATIONS TRIDENT External Speaker MSI90 /opt. amp $ 19.95 'W.! Design & Engineering Honors, Electronic Industries Old Scanner Repair, all brands S CALL Extended `1°' z Association. Trident TR2400 Total Coverage Receiver Warranties $ CALL Frequency Info FaxFact/Modem $ Trident TR2400: 100KHz to 2060MHz. Ten scan banks of 100 channels FREE each, ten search - On Glass Mobile Antenna $ 32.95 banks. Tuning increments as low as 1KHz. Beat Freq. Oscillator for SSB and CW modes. Search lockout and store. VFO tuning knob. Permanent memory. Bank lock and 2 Way Radios I I linking. Attenuator switch. Backlit LCD. 1 Yr Warranty. AM/NFM/WFM. Selectable Vitr'hi-barid 'programmable increments . Delay, Hold, Priority. 5 7/8H x 1 I /2D x 2W. Wt 14 oz. $499.00 mobiles as low as $299.95. Call for quotes or Fax Fact #775

1 Toll Free, 24 Hours! 800 -445 -7717 Fax Orders 800-448 -1084 Fax Facts 317-849-86831 Computer BBS Modem & Fax/Modem, 317 -579 -2045. Toll Free Tech Support, Dial 800 -874 -3468 I International Fax: en Espanol, en Francais, und auf Deutsch, or just fax in plain English to: 317 -849 -8794 1 ACE Communications 6975 Hillsdale Court, Indianapolis, IN 46250 7-01 Service & Support hours: Mon. -Fri. 9AM to 6PM, Sat. 10-4 EST. Mastercard, Visa, Checks, Approved P.O.'s & COD (add $5.50) & AMEX, Discover. Prices, specifications and availability subject to change. Flat rate ground shipping and handling charge only $6.95

per unit. Express Air only $9.95 , for most units, to most locations. One week trial, no returns loot 0010 accepted two weeks after original 1 receipt without substantial restocking charge. All units carry full factory warranty. Indiana residents add 5 per cent sales tax. FLY /II ONLY $9.95 L J CIRCLE 125 ON FREE INFORMATION CARD

www.americanradiohistory.comAmericanRadioHistory.Com Check Out These Deals From CIRCUiTSPECIALISTS! Circuit Specialist's Positive Photo Resist Electronic Soldering System Pre -Sensitized Printed Circuit Boards Here's the ideal solution when Tempera- These pre- sensitized printed ture Control is required. Easy to use slide circuit boards are ideal for control allows user to set system from 300 °F small production runs. They to 840 °F. Voltage to iron from control unit provide high resolution and is 24V. Iron heating power is48W. Replace- excellent line width control. able 5.3mm tip is standard. Replacement high sensitive positive resist irons and tips are available. PRICE EACH coated on 1 oz. copper foil CAT NO DESCRIPTION 1 5 allows you to go direct from SL10RE Temperature Controlled $56.00 $50.00 your computer plot or art work Soldering Iron layout. No need to reverse art. SL24VRE Spore 24V Soldering Iron 10.50 7.50

Single- Sided, 1 oz. Copper Foil on Paper Phenolic Substrate PRICE EACH Electronic Soldering SystemAs Low CAT NO DESCRIPTION 1 10 50 with LED Display AS $7500 PPIO1RE 100mm x 150mm/3.91" x 5.91" $2.55 $1.90 $1.70 PP 114RE 114mm x 185mm/4.6" x 6.6" 2.98 2.45 1.98 temperature controlled system with PP152RE 150mm x 250mm/5.91" x 9.84" 5.40 3.98 3.60 Deluxe maximum accuracy. Tem- PP153RE 150mmx300mm /5.91 "x11.31" 6.15 4.48 4.10 LED display for perature is adjustable from 160° -480 °C (320° - Single- Sided, 1 oz. Copper Foil on Fiberglass Substrate is48 Watts. Runs on PRICE EACH 900°F). Iron heating power 24V from controller unit. Replacement iro`ts CAT NO DESCRIPTION 1 10 50 and tips are available. Tip size is 5.3mm. GS1O1RE 100mm x 150mm /3.91 "x5.91" $ 3.90 $2.98 $2.60 PRICE EACH x 3.49 3.20 GS114RE 114mm x 185mm/4.6" 6.6" 4.80 CAT NO DESCRIPTION 1 5 GS152RE 150mm x 250mm/5.91" x 9.84" 8.69 5.98 5.78 SL3ORE Deluxe Soldering System $86.W $75.00 GS153RE 150mmx300mm /5.91 "x11.81" 10.20 7.20 6.80 SL24VRE w /LED Spare 24V Soldering 10.50 7.50 Iron for SL10 or SL30 Double -Sided, 1 oz. Copper Foil on Fiberglass Substrate PRICE EACH

CAT NO DESCRIPTION 1 10 50 Replacement Tips for SL 10/SL30 GD1O1RE 100mm x 150mm/3.91" x 5.91" $ 5.07 $3.68 $3.38 GD114RE 114mm x l 85mm/4.6" x 6.6" 5.95 4.29 3.99 We now offer a variety of replacement tips GD152RE 150mm x 250mm /5.91 "x 9.84" 10.47 7.39 6.98 for the SL10 /SL30 soldering stations. GD153RE 150mmx300mm /5.91 "x11.81" 11,95 8.69 8.30

Etching Chemicals /Ferric Chloride PRICE EACH tì,1 D1425/ ff CAT NO DESCRIPTION I 5 821 RE 1/32" Pencil Tip S 39 5 .19 826 822RE 1/32" Pencil Tip .39 .19 1/64" Pencil Tip .39 .19 A that mixes with water to 823RE dry concentrate f,;`f> 824RE 1/16" Chisel Tip 49 29 make 1 pint of etchant, enough to etch 400 825RE 1/8" Chisel Tip .49 .29 sq. inches of l oz board. 826RE 3/64" Chisel Tip .49 .29 39 PRICE EACH 827RE 3/64" Pencil Tip .59

CAT NO DESCRIPTION 1 5

ER -3RE Makes 1 pint $3.50 $2.75 RECEIVE YOUR .° OUTPERFORM Developer FREE COPY OF rh.n .11 This product is used as the developer on our positive photo -resist printed circuit boards. OUR 100 PAGE Includes instructions. 50 gram package, mixes

with water, makes 1 quart. CATALOG! PRICE EACH Its chock full of all types of elect- CAT NO DESCRIPTION 1 10 25 ronic equipmentand supplies. We've POSDEVRE Positive Developer $ 95 $ 80 $ 50 got I.C.'s. capacitors, resistors, pots, equipment, bread- Etching Tank inductors, test boarding supplies, PC supplies, industrial computers, REDUCES ETCHING TIME! data acquisition products, personal computers and computer parts, plus much, much more. FAX us your This attractive injection moulded de- name and address or call 800- 528 -1417, ext. 5 and leave signed tank is ideal for etching your a message on our catalog request line. PCBs. It includes a thermostatically CIRCUIT SPECIALISTS, SINCE 1971 controlled glass heater, electric agi- tator and PCB hanging accessories. Measuring graduations are included. 800- 528 -1417 Maximum PCB size is 160mm x 250mm or 200mm x 250mm w/o heater. Typi- 602 -464 -2485 cal etching time is 4 minutes. 602- 464- 5824(FAx) CAT NO DESCRIPTION PRICE WE ACCEPT: ETIORE Etch Tank System $52.00 VISA, Mastercard, Discover Card

QUANTITY PRICING DOES NOT APPLY TO MIXED ITEMS' & American Express 101

www.americanradiohistory.comAmericanRadioHistory.Com RRINROÍ'W KITS

INCLUDES STROBE The Exciting New Laser Pens 2 AAA Batteries LIGHT Pen Size: 51/2' x 1/2' Do you need TELEPHONE MONITOR 4mW an attention getter, warning Beam visible up to 500'. SUPER light,or flashing light for model NEW LOW PRICE DANGER airplanes? Then this kit is for you. Use it as an emergency light for your Lacer Radiation AVOID DIRECT auto, radio tower, even use it on your EYE EXPOSURE bicycle. Has a variable flash rate. Lase, radiation u omitted from Monitors the APERTURE Size 3.5'x1.8' operates on 6 or 12v your phone system, LASER RODE W...lanaa, 170n,n See how accurate Mu ORS. .eW CLASS SIS DC only. your phone USER PRODUCT ST -1 $9.95 company really is!

1. RECORDS OUTGOING CALLS : MICRO-MINIATURE MICRO- MINIATURE WIDE BAND Date & time of each call. PREAMP PHONE S Length of the call. The ideal preamp MIE TRANSMITTER So small you could What number was dialed. for scanners, hand We havent seen a smaller hide this one on some If you use a credit card it records held phone transmitter than the radios, fre- real bugs! It's the MMPT2 kit. Powered the card number. quency counters. by smallest we've ever the phone, it requires no Amplifies low level seen. With it's super sensitive mike it trans- 2. RECORDS INCOMING CALLS : battery. Transmits bo h sides of a phone conver- (weak) signals. If he signal is mits a whisper or a room of conversation to an Date & time of extreme- sation to an FM adio up to a 1/4 mile call. FM radio, tunable from 88 to 108MHz FM. ly low 2 amps can be used in series. away.Tunable from 88 to 108MHz FM. Attach it to How many times phone rings. With a proper antenna & 9v it transmits about 1MHz to 2.5MHz CD 2.8dB of 1dB com- one phone or add i to the line to pick up all If 1 mile. The kit is made with surface mounted answered the length of call. pression = +0 gain: 1 incoming calls. The MMPT2 is undetectable if dBm MGHz -20dB parts, we have already mounted these parts. properly installed. Uni has surface mounted parts, 3. RECORDS ANY DTMF TONE : to 2.5Hz -6dB Requires 12vDC © 16Ma You install the leaded parts. Can operate on 6 you install the leaded parts.Size .45'x.6" Detects any tone on line sent by WBA -6 $19.95 to 12v DC. Size .35'x.9' MMPT2 $29.95 MMWM5 $34.95 phone company or any other source. Records to Screen or Floppy Disk WIRELESS FM TV NOTCH MICROPHONE FILTERS EASY TO INSTALL FOR CHANNELS Small but mighty Connects to parallel port this little jewel will 2 thru 22 Our TV filters Phone line in. out perform most SNOOP & eliminate unwanted Phone line out to telephone. units many times its TV channels or price. It really BULLET interference that alters both All software included! stomps out a signal. The WM -1 kit is a buffered wireless m'ke that operates from sound and video with a beep - beep - beep. 80MHz to 120MHz FM , the frequency of any broadcast FM adio. Includes mini - TM -1 ONLY MT a NOTE: All TV Filter Kits are sold for educational purposes only. You must obtain permis- $9995 electret mike. SIZE: .85(1' 6 to 12vDC sion from your local cable company before using these filters on your cable system. WM -2 $14.95 DF -222 Kit $14.95 BUILT$16995 FM STEREO TRANSMITTER 5.0 mW This Manual contains all Own your own FM radio Laser Diode schematics, parts lists , P.C.B., station. Any stereo signal Great for making a layouts for most of the Rainbow you plug into the FMST- gun sight, use as a 100 will be transmitted to transit, makes a Kits. Use your own parts to any FM radio tuneable super experimenters construct any of our kits. from 76 to 108MHz FM. Transmit a wireless link project. The beam is through an auditorium, from your car to your visible with a wavelength of 670 nm. Size of camper, listen to your cd's while mowing the KIT beam is 6mm at 5 meters. Operates on 3 BOOK lawn,Play music on one channel sing on the other. volts DC at 85mA. Size: 10.5mm x 18.5mm Clarity is excellent, aprox. 40dB stereo separation. with an adjustable collimating lens. $14.95 Length of antenna determines the distance of transmission. Complete with stereo input level $9.95 with the purchase controls , & crystal fo stereo separation. 9v bat- LDM-5 of any kit. tery operation 4G FMST -100 $29.95 / FMSTC cabinet $8.95 Please add sufficient postage First lb $5.00 Canada $7.00 PHONE SUPER SNOOPER Additional LB. Add $1.00 US FUNDS ONLY TRANSMITTER BIG EAR We will accept telephone orders for Visa or Mastercard Small but mighty,it fits Listen through walls, anywhere. Phone line hear conversations powered, never needs across the room. Add MasterCard To Order Call batteries. Transmits a parabolic reflector both sides of a phone and hear blocks 317- 291 -7262 conversation loud and clear, wireless, to any away. The BIG EAR can be hidden about FM radio at great d'stances. Variable tunes anywhere. Makes an ultra sensitive inter- com. Can be used a 1.5W AMP. from 70MHz to 130MHz FM. You can also as We supply a mini -electret mike in the kit. use it as a speaker phone. SIZE .5 "x1" (ELECTRONIC RAINBOW SIZE: 1"x.75" 6 12vDC . = to TEL -B1 $12.95 AA -1 $10.95 6254 LaPas Trail Indianapolis, IN 46268 FAX 317- 291 -7269 102 BUILT $29.95 BUILT $29.95

CIRCLE 147 ON FREE INFORMATION CARD

www.americanradiohistory.comAmericanRadioHistory.Com CircuitMaker®vs. Electronics Workbench®

A NEW STANDARD HAS BEEN SET ! State -Of- The -Art Analog Simulation Superior Digital Simulation CircuitMaker's analog simulation results are shown in graph win- CircuitM ker has an exclusive Trace feature where the state of every dows that provide powerful, interactive analysis options. You can node is indicated in color as the simulation runs. You can monitor as plot multiple waveforms by clicking on the desired nodes and can many waveforms as your screen will allow, set edge or level break - select linear or logarithmic axes. Horizontal and vertical cursors points for analysis, and interactively see the state of any node by facilitate quick and-accurate measurements. You can also zoom in on the logic probe to it. The data sequencer provides 1U24 words any portion of the graph to obtain additional detail. of pattern data. Additional digital instruments include ASCII and HEX input keys and an ASCII display. CircuitMaker includes tri -state Electronics Workbench offers a single, small scope or Bode plot devices and devices have programmable propagation delays. Instrument window. The windows are not sizeable and only two waveforms can be plotted at a time. EWB has a single measurement Electronic Workbench has no interactive logic probe or Trace cursor and provides no direct way to read results from the instru- capability and no Hex or ASCII keys. Their ' word generator" is ments. limited to 16 words. EWB does not have tri -state devices and digital devices do not have programmable propagation delays. o.I ClrcufìMaker - - I I File Edit Macros Options View L1 L2 L3 L4 L5 L6 L LO L9 L10 4iICIM[] IMI® NQV= OMED WI o C1CM25tANAL OG.CIR« 100X(1) - o DC Analysis (4) Ai*I -:°:' %b:-150 -b_ lBO.Oa BOk a ïa: 12.19 Yb- 5.519 -b: 6.601 V cc i oI ,,,61 '7 v,r, ul DC(3) 7 lOk Ul Jl jA041 1: 00Ì `% : :,I 10_kHx -.ow 100aV AL N 5k > Va. i y 7 rcu r1 . ..

1 , y ' ' %volctf.'IV) r + ' ' A.[.rowd \ I1 _ _ II .`rr'" . ilÿ i , 1'. .6 I Ol. x. - 0 a _0 -b: , _Ja . _ -3.0 ' ARPO c , onun.m w.Imm I.m n '1 .,q'hp nli.1nili..wl ..II 11111 I .. IW1!1

Comprehensive High -Performance Device Libraries Schematic Capabilities

CircuitMaker includes libraries containing --. .... CircuitMaker puts you in control of your programmable, TTL, CMOS, generic analog schematic with SmartW iresTM bussing, page and -digital devices, and many powerful 1/O devices. connectors, and rubberbanding. You can la- With CircuitMaker's macro function bel devices and pins, add fully stylized multi - you can quickly and easily create your own Competitive line text, and create a parts list or netlist. functional devices and symbols. Now that's With the Macro feature can add user giving you the tools you need to get the job Upgrade Offer you done right! defined symbol; to your device library. You deserve the best. Upgrade from any (Call Electronics Workbench dictates wire place- Electronics Workbench ships with only 17 competing roduct for only $149 ment to you. ER B limits your overall "work- digital devices. If you want additional devices for details-).-For new users CircuitMaker bench" layout to 2 byl pages. EWB has no you pay extra. is a tremendous value at just $299. bussing, age, connectors, pagebreaks, print scaling, labelingg, free text fields netlisting, Technical Support zoom, undo, and no Toolbar or toolbox. MicroCode Engineering, supports its customers with free unlimited phone support from knowledgeable FREE engineers. And, you won t find yourself endlessly listening to music when you call for help. The quality FUNCTIONAL of our customer support isi unmatched! DEMO C(.mr nson fused un Cir.u,Meker 2 n for Window. and EIe.tron ., W at 3 0 fur Windnova. All p and are uadem_rk, uf rheu VERSION MicroCode vailahle on most major BBS' Engineering or sent direct for $10 s &h CALL 800- 419 -4242 Oret, UT 84057 USA pilzio Phone (801 )226 -447( Fax (801)226 -6532 103 CIRCLE 42 ON FREE INFORMAT ON CARD

www.americanradiohistory.comAmericanRadioHistory.Com QUALITY PARTS DISCOUNT PRICES FAST SERVICE HUGE SELECTION

JUMBO LEDs SUPER SAVINGS (USED) 9 VOLT 60MA 6-` SUPER VHS TAPES Liton # LTL 327C - 8MM SOLAR PANEL Super VHS tape users! Save Ideal for eye -catching indicators and a bundle on name -brand displays. A recent quantity purchase of These 6' X 6" glass enclosed S -VHS tapes, T-120. photovoltaic panels produce these BIG, 8mm diameter, red diffused These tapes were 9 Vdc at 60 ma. Ideal for LEDs enables us to provide some very used for a brief charging batteries and pow- special pricing. The leads on these devices are wing small devices. Put two period, then bulk 0.325' long with plenty of room for soldering. or more together for more erased. The record - current and voltage. Includes Uo protect tabs have hook -up instructions. 5 for $1 been broken out, 100 of $E5 0 0 CAT# S -VHS CAT # SPL -960 so you will have to 1000 for $ 120.00 cover the notch with a piece of tape, but they $ 25 work great and cost a fraction of the "new" price. each GREAT DEAL! Try some, you'll be back for more. 5 SURFACE MOUNT $3óo 10 for $28.00 100 for $250.00 SPEAKERS each 7 Vdc MOTOR Matsushita These surface mount speakers were designed for SMALL # MMX- 7AC O 8A use with car stereo, but they will 1.25" diameter x 1.25" high work as well, or better as inter- ELECTRET MIKE motor. Prepped with 1.61" com or communications diameter flywheel, pulley in your home speakers or and fiberglass mounting CAT# DCM -54 workshop. board. 10 for $9.00 0.31" diameter X 0.325 ". $1 00 100 for $80.00 0.7" long leads terminated with a two pin con- each nector (0.1" centers). $1 75 CAT # MIKE -18 each A.C. LINE CORDS

4 ", 4 ohm, speakers mounted in an unbreakable black plastic, slant -faced MINIATURE SWITCHES 6 INCH IEC POWER CORD enclosure. They are rated 5 watts. Enclosure measures 4.82' X 4.5" X 2.45'h. Each pair is D.P.D.T. boxed and includes two short (ON -ON) pieces of hook -up wire. $0175 ALCOSWITCH ä MTM206NPC THATS RIGHT! 6 INCHES...Standard 3 prong perr pair Short bat handle 0.25 long. CAT# SK-411 grounded male one end and 3 prong IEC recep- PC terminals @@ tacle on other end. CSA listed. Large quantity CAT # MTS -82PC $ 25 available. VIDEO 1 each "HI -8" # LCAC -36 25 for $25.00 100 for $90.00 $1 00 CAT CASSETTE (USED) 2 for 10 for $4.50 100 for $35.00 8 mm Video Camcorder Users!. MINIATURE D.P.D.T. SONY Hi -8 PUSH /ON PUSH /OFF ROUND 4' BLACK 16/3 CORD Top quality, metal particle Augat/Alcoswitch a MPE206N 120 minute video cas- Miniature DPDT, push/on push/off switch. settes. Used for a short Splashproof: O -ring on shoulder and inside movable shaft provides moisture seal. time, then bulk-erased. 0.32" od, SJT insulation. Standard 3 prong Rated 6 amps ® 125 Vac. RED 0.4" dia. cap. 0.25" Each cassette has its own grounded plug one end, moulded strain relief diameter threaded bushing. 0.8" behind panel depth. plastic storage box. on end. Pigtail leads. CSA listed. Solder lug terminals. UL and CSA listed. other Satisfaction Guaranteed. each Large quantity available CAT# MPB -20 CAT # VCU-8 75 CAT # LCAC -35 1 25 for 100 $150.00 $1 each 10 for $28.00 100 for $250.00_ $ each $37.50 for MANUFACTURERS - We Purchase EXCESS INVENTORIES... Call, Write or Fax YOUR LIST.

CALL, WRITE ORDER TOLL FREE 1 For A -800-826-5432 or FAX MAIL ORDERS TO: ALL ELECTRONICS CORP. FAX (818) 781 -2653 Free 64 Page P.O. BOX 567 VAN NUYS, CA 91408 -0567 INFO (818) 904 -0524 CATALOG. NO MINIMUM ORDER All Orders Can Be Charged to Visa, Mastercard or Discover Checks and Money Orders the U.S.A. Accepted by Mail Orders Delivered in the State of California must include California State Sales Tax NO C.O.D 104 Outside Shipping and Handling $5.00 for the 48 Continental United States - ALL OTHERS including Alaska, Hawaii, P.R. and 77[R $2.00 postage. Canada Must Pay Full Shipping Quantities Limited Prices Subject to change without notice. L send CIRCLE 28 ON FREE INFORMATION CARD

www.americanradiohistory.comAmericanRadioHistory.Com PHONE: 1-516-756-1750 FAX: 1- 516 -156 -1163 KELVIN ELECTRONICS 10 Hub Dr, Melville, NY 11747

KELVIN 200LE THE ULTIMATE METER Popular Electronics (reviewed 5/93) "Not only does the Kelvin 94 boast a lot of .4u-_ features...the features go the extra distance." "If we had to run into a burning building to ._ do some emergency trouble -shooting and 1 could carry only one piece of equipment, the Kelvin 94 would he n .+e:.,.xK it!' *True RMS, LCR, Hi, dBm * 0.1% Accuracy * 12 INSTRUMENTS IN ONE! 100 -LE 150 -LE 200 -LE 400 -LE DC Voltmeter, AC/DC Voltages Transistor Freq. Counter Inductance AC Voltmeter, Cont. Tester- up to 20MHz Ohmmeter, Battery Test resolution of 1 uH Buzzer Capacitance AC Current, DC Current Freq. Counter 3 -1/2 Digit LCD from 1 pF to 20uF DC Current, Low Battery 10 Amp Transistor up to 20MHz Diode Tester, Indicator AC /DC Current Cap. from Audible Cont. Battery Test 10 Amp 1 pF to 200uF Tester, dBm, #990087 #990122 #990123 AC /DC Current Freq. Counter, 51985 $2995 sq,9es Transistor Capac. Meter, Inductance Duty % Meter, AC /DC Voltages STANDARD A DC Current Resistance 20 Continuity Tester Buzzer Diode Test Amp Logic Probe 10M ohm Input Imp. Accuracy RDG :FEATURES: +/- 0.5% #990124 KELVIN TRUE FINS 94 #990111 Protective Meter Cases for 100 -300LE ....990088..$4.95 $7995 do. Protective Meter Case for 400LE 990094..$4.95 519995 2MHz Sweep Function Protek MB °8011-L Generator Protek p003L o Output Frequency of 0.02Hz to 2MHz on 7 ranges o Output: sine, triangle, square, sl' I I .»., , I.:,.... 'Irz: pulse, ramp or slewed sine wave í Il - (r9.41r:" .. o 4 digit frequency counter o With sync output (TTL), VCF, DC offset, variable symmetry o Square wave rise time: 100ns or less $29995 #720129 Regulated DC MODEL 20MHz Power Supply Protek P -3502C "Afford -A- Scope" o 0 -30V, CV; 0 to 3A, CC o 2 Channels o 2 Seperator LED displays (green for voltage, red for o Built -in component tester for current) Constant voltage & constant resistors, capacitors, and diodes o current operation o 6" CRT with internal graticule o Fully isolated outputs allow o TV trigger series or parallel operation Invert o CH2 o Includes (1) set of test leads & o 2 -Axis input operation manual 2 o Includes probes o Overload p - otected o 2 -Yr. warranty o 2 -Yr. warranty $ 105 #720085 385 $25

CIRCLE 38 ON FREE INFORMATION CARD

www.americanradiohistory.comAmericanRadioHistory.Com New and Pre-Owiied Test Equipment

Substantial SAVINGS on New & Pre -Owned B +K Precision, Fluke, Hewlett -Packard, Goldstar, Leader, Tektronix, and more -..

o GoldStar Precision Pre -owned Oscilloscope Specials New Oscilloscope Specials Tektronix 465 100 MHz $499.00 Tektronix 465B 100 MHz $599.00 Tektronix 475 200 MHz $749.00 Tektronix 475A 250 MHz $849.00 Professionally Refurbished Calibrated to Original Specifications Dual Channel, Calibrated Delayed Sweep 90 Day Warranty Model OS -9100P Full 100 MHz Bandwidth! Art` MY 11.0 INT'EpNATlONIM_ Cali1O. SUPER SALE! S999.00 TV Synchronization Trigger NTSC Generator with RGB Dual -Channel, High Sensitivity Model 1249A $569.00 Calibrated Delayed Sweep FASE SHIPPING! NTSC Color Bars ± 5° and ± 5 IEEE Units Two Probes Included ON ALL GOLDSTAR EQUIPMENT Ch. 3, 4, and IF Outputs Crystal Controlled ANYWHERE IN THE U.S. 2 Year Warranty Excluding AK & Calibrated I Vp -p or Variable Composite Video Output 7 It RGB Outputs on BNC or 9 -pin D Connector Model OS -904RD Composite, Vertical, and Horizontal Sync. Outputs On- Screen Measuring Cursors & Readout! Interlaced or Progressive Scan 40 MHz Bandwidth S699,00 1 Year Warranty Professional Quality DMM Hand -Held Parts Tester at an Affordable Price! Model 815 $99.00 Model DM -334 $99.00 Large 0.8" digits, 26 User Ranges 3.75 Dgts, 4000 Cnt, Auto Ranging Tests Transistor hFE and Leakage Iceo DC /AC Volts (1000/750V) Checks SCR's, Diodes, LED's, Capacitors, and Resistors DC /AC Current (10 A) Tests Resistance (40 Meg Ohm) Batteries Under Actual Load Conditions Bar Graph. Min /Max, Data Hold 1 Year Warranty Frequency Counter (1 MHz) Safety Holster & Test Leads Included 1 year Warranty

Full line of Oscilloscopes, RF, Video & Audio Test Equipment, FOTRO N I C Power Supplies, Meters, Probes and Accessories. CORPORATION P.O. BOX 708 TOLL FREE 1-800-99-METER Medford, MA 02155 VISA AMEX FAX (617) 665 -0780 106 IIMNE C.O.D. 1- 800 -996 -3837

www.americanradiohistory.comAmericanRadioHistory.Com NEW PRODUCTS Electronic Equipment Bank...Nation's Largest Radio Outlet! HF 150 AOR AR2700(^) .5-1300MHz(' -" 11001r SDU5000A L O W E Rated * * ** by IBS. 30kHz Replaces older AR1000/TR1200 Imagine "seeing" the spectrum up - 30MHz, 60 memories, multi - models w/Hi Quality surface mount to ±5MHz from the station you're tuned to. A Spec - mode AM/AMN/LSB/USB /CW, technology, many advanced features, ral Display Unit (SDU) allows just that. Input power 10- 15VDC, 120VAC incl, cloning, computer I/O (opt. RS232 10.7MHz (ICOM 7000, 7100, 9000, mod AR3000A synchro detection. OPTIONS: converter), 1000 memory 50ch x 20 PRO2006, digital control AR3000 or 1CR7100) SDU5000A (AOR) $995.00 Keypad, RS232 computer bank, AM/FM/FMW auto band. control, List $499.95 SONY ICF SW7600G PR150 Preselector (shown), Introductory $...CALL AP150 (shown) SONY's hot selling RK150 (shown) .5- 1900MHz'' A01g` ÁR8000 '' LIST $699.00 EEB $599.00 The only TRUE SSB scanner on receiver now at an the market. Listen to AM /SSB voice from unbeatable price!! Bemat Scanners around the world as well as local signals. BC3000XLT 25- 550/760- 1300MHz' n Several new -patented features. Alpha - AM/FM/SW /SSB /CW Digital Scan 100ch/sec, search 300ch /sec, 400 Numeric, 4 level LCD read out, bar list $$249.95 EEB $199.95 memory channels, 20 x 20 banks. graph "S" meter, Band scope spectral LIST $499.95 EEB $369.95 display, computer I/O (opt. RS232 & NOW $169.95 Software), 1000 memory 50ch. x 20 BC9000XLT 25 -550 /760- 1300MHz"' ( AC adpt. AC -E6OHG $24.95) Alpha numeric LCD on all 500 memory ch. Scan banks. At time of purchase ask for a FREE Radio Stand and KOSS List $799.00 Headset (No Dealers Please) 100 ch/sec, search 300 ch/sec, data skip, SW Special Sale $599.95 Other SONY's at Special attenuator 15dB, Cor recorder control. Spring Prices LIST $769.95 EEB $389.95 BCT -7 All Band 26- 956MHz'" AOit AR3000A .1- 2036MHz' ICFSW55 $339.95 ICFSW100 $344.95 A must for the frequent highway trav- Compact, Professional quality, a favorite with many ICFSW77 $459.95 ICFSW30 $104.95 eller. 7135 preprogrammed channels, agencies that want Hi- Performance at a low cost. All ICF2010 $344.95 ICFSW33 $159.95 mode, including SSB, one small unit does it all. 400 search by state & service. Police, HP, DOT, Fire, memory 100ch. x 4 banks, RS232 computer ready GRU DIG SAT700 News, WX, CB, plus 100 User memories, scan 100 (opt. DOS & WINDOWS soft- $388.00 ch. /sec. LIST $319.95 EEB $179.95 ware) EEB offers many Other BEARGAT Scanners... options to satisfy any BC120XLT $144.95 BC760XLT''" $229.95 special need...CALL YB400 SC150Y/B" $194.95 BC860XLT" $189.95 List $1195.00 $188.00 BC148XLT -1'' $99.95 BC890XLT''i $244.95 EEB $1029.00 BC220XLT" $229.95 SANGFAN

l';uduç I cdlullc.dnm Ill (;Ilul:,i IlniAutl,:.bn,,bl. REALISTIC SAVE!!! IL ('rllulur 14Lk'k. bul ran h: r:.wrd ATS606P $169.00 t, Mocked. SINI- 41NI\III/. ATS818 $169.00 CALL EEB before you buy 1 n IILorkrdlt.F.m,pinhlladUn\;r.tthnt..I' ,pot L;lc .l PRO 2035 $359.95 ATS818CS $219.00 PRO 62 $259.95 `"I' ilOI{ AR3030 30kHz -30MHz I" PANASONIC FREE Catalog... Superior Performance & value, leading edge tech- RFB45 nology in an HF receiver design. Compare features . By now you should have our 95 with receiver costing over $1000. Collins Filter, $159.00 Catalog. If not...CALL/FAX/Write AMW 6kHz opt, .5, 2.4 & 4kHz. DDS tuning, 3 ant. DRAKE Both Hot Sellers... ;Inputs, 10Hz step tunin' R8A Special $1069.00 today! Sync AM, RIT. RS232 SW8 Special * 96 Pages SWL ready (opt, Software). $679.00 Scanners Amateur List $949.00 2 -way GPS Enlarged EEB $799.95 (leek out EEB's NEW BBS!!! book section FREE CW filter or VHF converter Dail in and give us your continents nor EREL in the U.S., 3rd class (4 weeks). $2 1st class (1 week). $2 Can/Mex. $5 elsewhere. (tell July)...a $149 value! 1- 703438 -3781 ELECTRONIC [(Hill'MIiN"l' BANK ORDERS: K00-365-3270 *Sorry. no C. )I Y\ , Free c:uatlo_' in USA 3223 MILL Sane( NE L(,ral Tech: 703-93S-3350 Ihrice. Suhiccl tu changr Vicuna, VA 22150 I'/\X: 7(13-938-69I I Price\ du n, t include freight

\\; ac.: pl \ IS \/\la.l:ll ;u,l' \mrn:an pir../UI.:,,; \\; .lup , IA I I cd; I,d I ync.. aud Al.ul I(eltlril\ \IIhYCI'I lU' rc\luek fee up to 20`r 107

www.americanradiohistory.comAmericanRadioHistory.Com r PROBE MASTER -Heavy Duty Scope Probe 3900 SERIES

RUGGED FIXED TIP (.055" DIA.) 12 PIECE KIT $Ì5

PM3915 Master Kit 100 MHz

$26 MODEL 3901 -2 SHOWN USA 100 MHz SWITCHABLE lx, REF, 10x REPLACEMENT PROBE KITS PROBE ONLY The PM3915 "Master Kit" contains LENGTH BW MHz RISE TIME LOADING V 1 three probes (a 1X, 10X and switchable MODEL ATTEN. FT. M. AT-3DB ns pF mû PRICE MODEL PRICE SWITCHABLE probe) in a high impact protective 3901 -2 1X/R /10X 5 1.5 10/100 35/3.5 57/15 1/10 $26.00 3901 -2P $20.00 case. Included are sprung hooks, 3903 -2 1X 5 1.5 26 13.5 54 1 $24.00 3903 -2P $20.00 ground leads, trimmer tool, and a 4" 13904 -2 10X 5 1.5 100 3.5 15 10 S25.00,904 -2P $20.00) extender tip.

Modular Test Lead Kit 9100 SERIES

INCLUDES: (2) Leads PM9152; (2) Probes PM9153; (2) Spade INCLUDES: (2) Leads PM9151; (2) Probes PM9153; (2) Sprung Hook Lugs PM9159; (2) Alligator Clips PM9156; (2) Extender Probes Probes PM9169; (2) Alligator Clips PM9156; (2) Spade Lugs PM9159; PM9154; (2) Minigator Leads PM9161; (2) Sprung Hook Leads (1) Pouch PM9175 PM9164; (2) .025" Wire Wrap Leads PM9168; (2) Pico Hooks for

W.W. PM4958; (2) Pincer Hooks for W.W. PM4956; (2) Sprung LOW RESISTANCE GOLD CONTACT Hook Probes PM9169; (1) Pincer Probe PM91 71; (1) Pouch RETRACTABLE SAFETY SHROUD

PM91 76 BLACK VINYL POUCH INCLUDED

SILICONE LEADS, BURN RESISTANT 18 GAUGE (440 STRANDS) 48" LONG

1000 WORKING VOLTS 10 AMP RATED VINYL STRAIN RELIEF

Softie Test Lead Kit 2000 SERIES BUY FACTORY DIRECT IT'S SOFT $19.90 IT BENDS 800- 772 -1519 V- 24 HOUR SHIPMENT 4110. L) (IF REQUESTED) SILICONE LEADS 90° 18 GAUGE MALE CALL FOR FREE CATALOG Solely (OVER 2(X) ITEMS) Standard Size Standard See Safely Banana Plug Banana Plug FAX 619 -258 -7413

PM2028S PM2043S SCREW ON ACCESSORIES 215 Denny Way PROBE MASTER El Cajon, California 92020 108 Ir

www.americanradiohistory.comAmericanRadioHistory.Com ARE YOU BEING "BUGGED?" EVEN AS YOU READ THIS, countless individuals and firms are being enormously damaged by having their private conversations overheard, monitored, and \or recorded. Almost without exception and AFTER the fact, the victims make a statement something f along the lines of "But, I never thought it OUR FINEST would happen to ME!" @w@tLc@@ L@wt@@ THE ULTIMATE IN "BUG" DETECTION EQUIPMENT "DEBUGS" ROOMS AND TELEPHONES! If you require GUARANTEED PROTECTION against electronic telephone monitoring devices and also require COMPLETE CONFIDENTIAL PRIVACY in certain rooms and areas, we highly recommend the COUNTER- SURVEILLANCE DETECTOR CSD -18. EXTREME SENSITIVITY! This is our finest piece of detection equipment! The CSD -18 quickly locates electronic eavesdropping devices it telephones, homes, offices, vehicles, boats, or concealed on the body. It will actually pick up many eavesdropping transmitters at ranges exceeding 25 feet! Extreme sensitivity is obtained via ultra- efficent amplification circuitry following the RF detection stages. Excellent quality Dynamic Headphones exclude ell CONDUCT A PROFESSIONAL external sounds to further enhance detector output SEARCH... ANYTIME...ANYWHERE! The presence of any "bug" is immediately indicated vie a pronounced meter deflection. The CS0 -18 quickly "homes -ir" Every newspaper and magazine article end every radio and TV on eavesdropping transmitters and immediately pinpoints FULL RANGE story discussing some their new episode involving "Bugging" location. The closer you get DYNAMIC " devices, to the "bug ", the further the continues to increase the ever growing demand for HEADPHONES electronic needle moves to the right. It's as simple es that. Counter -Surveillance "sweeps" and equipment. The very limited supply of competently trained and Counter -Surveillance equipped "FLASHING" LED WARNS YOU INSTANTLY! specialists has created e situation where "sweep" exceeding rates $250 per hour are now considered reasonable and appropriate. And, for maximum telephone security, the CSD-18 automatically analyzes a sophisticated series of electronic This is en exciting, immensely measurements interesting and profitable field that you can enter along the telephone line and converts the with a minimum investment. Two hours actual practice with the CSD -18 / analysis into an easy to follow, step by step, test procedure. will have you "reading" and No technical is required "clearing" telephones and rooms with professional ease knowledge or necessary. A visual and competence. The average indication (vie a flashing LED) immediately reveals fee for "debugging" a single telephone is over S the presence 9200.00. It requires of the various types of about 45 minutes to complete the job and once it gets telephone "taps" and the flashing around that YOU can provide sequence identifies the actual this service, you'll quickly have more clients than type of eavesdropping device. you can handle. Even if you choose to provide "sweeps" for only a number of friends small MAXIMUM SECURITY EASY and associates, your initial investment will quickly be returned - OPERATION! many times over. Latest Computer -Age IC circuitry designed ecclusivey for maximum security and ease of operation, assures the utmost privacy protection possible today against virtually all types of room "buns" and telephone laps ". The CSD -18 detects even the very latest uhra- sophisticated devices FREE BONUS! specifically designed to defeat detection via polarity negating circuitry -' Also includes multi -line option for testing business elephones FASCINATING HI -TECH THE ONE "BUG" INFORMATION PACKAGE TO FEAR MOST! MAXIMUM PROTECTION- INCLUDED FREE! While most individuals are now somewhat guarded in their telephone conversations, they still rather naively feel secure in The CSD -18 provides maximum protection LATEST EAVESDROPPING DEVELOPMENTS the "privacy" of their own home or office. However, the against ALL major catagories of surveillance most common type of tap used A detailed analysis of a variety of extremely presently by eavesdroppers equipment including: fascinating hi -tech devices and procedures picks up ALL SOUNDS AND CONVERSATION WITHIN A used for ultra -sophisticated audio and video ROOM....WITH THE TELEPHONE STILL ON THE HOOKI ALL TYPES OF "CONCEALED TRANSMITTERS" eavesdropping including infrared monitoring, "BUMPER BEEPERS" Due to this devastating capability, this "Infinity" tap (variously multi -data eavesdropping and Interception, "INFINITY" DEVICES miniature micro-wave devices, new methods referred to es Infinity Transmitter, Hookswitch Bypass, 3rd for listening thru walls, etc., with many Wire, Harmonica Bug, etc.), has become the "bug of choice ". "BODY" TRANSMITTERS schematics included. You'll learn about In flagrant violation of federal law prohibiting their use and "TELEPHONE RECORDING DEVICES" electronic voice changers, corporate spying, sale, in "SERIES" & "PARALLEL" PHONE TRANSMITTERS how data banks are accessed to research these devices various forms are openly advertised in anyone and anything, eavesdropping by many technical publications for es little as $75. Literally neighbors; space age personnel and vehicle thousands of these devices are now in the hands of tracking systems, how missing persons are unscrupulous individuals all over the countryl CSD -18 found, how lie detectors are deceived, and a response Complete fact-filled In to this ever -growing threat, a uniquely engineered $295 section on Eavesdropping Law. feeturs of the CSD -18 now also detecte Infinity type devices Including batteries, antenne /probe, headphones, all plugs anywhere "down the line ". BIG MONEY IN COUNTER -SURVEILLANCE & adapters, extensive information package and instructions. In other words, if anyone ... ANYWHERE ... is utilizing the Complete information describing the fantastic telephone tip and /or ring wires opportunities that are now open to trained to monitor your private room HOW TO ORDER Counter-Surveillance technicians and exactly conversations while your telephone is on the hook, you'll how a number of individuals and firms are immediately be made aware of it via e fleshing LED! Order NOW by Mail or Telephone. 10 DAY MONEY a huge bonanza the booming ¡reaping BACK GUARANTEE if you're not 100% pleased and Debugging- business! You'll learn how the 100% POSITIVE INDICATION ever increasing use of Electronic Listening The CSD -18 also flawlessly detects "Series" and "Parallel" completely satisfied. We pay shipping charges on Devices by investigative agencies, government telephone transmitters and "Telephone Recording Devices ". all prepaid & credit car -i orders. Add $15 for CODs. agencies, unscrupulous business competitors, And, a separate feature silently indicates when extension 1992 jealous suitors, etc., has created a tremendous phones are picked up or being used. The CSD -18 completely foi Great Southern Security demand for this type of service. elimina-es all doubt and guesswork. 513 Bankhead Highway (SF) Carrolton, Georgia 30117 EXCLUSIVE "LISTEN -IN" FEATURE! A comprehensive information package The CSD -18 will even allow you to "listen-in" to exactly what FASTEST : tHirlt;t CALL TOLL FREE JAM -PACKED FULL of some of the most the eavesdropper is monitoring. And, without the exciting and fascinating reading imaginable. ORDER Reads like a Jemes Bond novel, with one eavesdropper ever becoming aware that he has been detected! 1 800 732 -5000 Importent exception ..IT'S NOT FICTION! We ere unaware of ANY other detection equipment having this combined capability AT ANY PRICE! PHONE (_' V amr rc.,n DtlCWfA 109

www.americanradiohistory.comAmericanRadioHistory.Com EARN MORE CABLE TV Converters & Descramblers MONEY! Compatible with Jerrold, Scientific Atlanta, Pioneer, Oak, & Hamlin Be an FCC Equipment BRAND NEW! LICENSED 6 -MONTH GUARANTEE ELECTRONIC TECHNICIAN! LOWEST PRICES Volume Control & Parental Lockout Available Greenleaf Electronics - 1- 800 -742 -2567 NO ILLINOIS SALES Earn up to It is not the intent of Greenleaf Electronics to defraud any pay television operator $60 an hour and we will not assist any company or individual in doing the same. and more!

1 \ Learn at home in spare time. DESKTOP MANUFACTURING! F" a No previous experience needed!I o / only No costly school. No commuting to class. The Original Home -Study course prepares $595! you for the "FCC Commercial Radio- telephone License." This valuable license is your professional "ticket" to thousands of exciting jobs in Communications, Radio - TV, Microwave, Maritime, Radar, Avionics and more...even start your own business! You don't need a college degree to qualify, but you do need an FCC License. No Need to Quit Your Job or Go To School THIS IS THE MACHINE YOU'VE BEEN WAITING FOR! Have you ever dreamed of letting your computer manufacture products directly frcm This proven course is easy, fast and low your CAD drawings', If so, the Neuractor CNC -4+ Desktop Manufacturing System may cost! GUARANTEED PASS You get your be just the edge you needi This fourth- generation CNC machining center can FCC License or money automatically drill, mill and route three -dimensional products in wood, plastic and light refunded. Send for metals DIRECTLY FROM YOUR CAD DRAWINGS! You 've seen the rapid- prototyping Er FREE facts now. MAIL COUPON TODAY! and "Santa Claus" machines that cost thousands of dollars, but did you know that as an electronic technician you can assemble one yourself from this inexpensive it Or, Call 1- 800 -932 -4268 Ext. 240 Utilizing patent pending technology the Neuractor CNC -4+ kit provides you with everything you need to machine products in three dimensions with a resolution of .001" ro All mechanical components are pre -fabricated, pre -machined, plated and painted. 1 commanD PRODUCTIOMS Includes four 83 oz /in digital CY- MOTORs, interface card. 5 amp power supply, 10 pitch ó I FCC LICENSE TRAINING, Dept. 240 I steel lead screws, 4 proprietary Slide Block actuator mechanisms, 4 aluminum linear actuator channels, polished steel guide -rods. Dremel bracket, hardware, etc.. (You a- I P.O. Box 2824, San Francisco, CA 94126 provide Dremel MotoTool(tm) or flex -shaft router and work surface ) It's a complete kill rn . Please rush FREE details immediately! All you do is put it together and calibrate rti IF THATS NOT ENOUGH, WERE THROWING IN A FREE FULL -FEATURED 3D CAD /CAM SOFTWARE PACKAGE WITH NAME I EACH UNITI Large 18"x18N4 6" cutter travel for crafts, electronics and printed circuit -making, I ADDRESS I board drilling and routing, not to mention model mold -making and even painting! Get started by ordering your own Neuractor CNC -4+ today' ACT NOWI Kit CITY _ STATE ZIP $595 + $24.95 UPS S /H. (For heavy -duty upgrade add $149) Allow 4 -8 weeks for

J delivery U S CYBERLAB, 14786 Slate Gap Rd , West Fork, AR 72774 (501) 839 -8293. Free info! X -Y Power /Rotary Tables and larger CNCs now availabie!

www.americanradiohistory.comAmericanRadioHistory.Com SETING THE STANDARD SA130011 SPECTRUM ANALYZER

SWEEP IF GFLM wow RANKERS SPEED vEST rY WO., -MOM

,eu KAU/4

C[içrIOU MHZ aNZ SYNC ea ® US ÓB P[NIdV TOP OF SCREEN LEVEL

TRACK.; DISPLAY CENTER f REOUENCY( MNZI GENERATOR COURSE FINE TUNE aa

ow i FarEa

n m.

6" x 12' x 16" (H x W x D) (only 16 LB) SAI800C Shown $2396.0

MADE IN THE USA 1 -1300 MHz In One Sweep $1995.00 1 YR WARRANTY COUNTER SURVEILLANCE, CATV, AM-FM-SW, TWO WAY -HAM RADIO, FCC TESTING, SATELLITE SPECTRUM ANALYZER /DISPLAY MONITOR $995 CHOOSE FROM 2 FULL FUNCTION ANALYZERS Screen, -110 Sensitivity, The SAMOA easily attaches to any receiver IF output jack. Providing Quality & Performance with 80dB on dBm +1- 50 a panoramic signal display of your scanner or communication receiver. Center Freq. Display, 5KHz Narrow Band Filter MHz Marker. Speed, The SA500A is a Full Function Spectrum Analyzer with +/- 51(Hz DISPERSION ZOOM, Baseline Clipper, Adjustable Sweep 300B 1- 1300MHz Narrow Band Filter, Center Freq. Display, 50 MHz Marker. SA500A Video Filter, and 40dB Input Attenuation. SAI The first affordable Professional Spectrum Monitor/Analyzer for all SA1800B 1 -1300 & 850- 1850MHz $2395 With Opt. 1,3,5,6 serious Ham Radio and Radio Monitoring Operators. With Opt 1,3,5,6 1.3GHz F ll.l:OIJIEN(;Y COUNTER .001 ppm $499.00 ITC FC1300: the first truly Accurate low cost Frequency Counter. Accuracy is the #1 Frequency Counter Requirement. The $200 - $800 counters being advertised the past few iUUÚÚÚUU years are but toys when it comes to accuracy. These guess -so-matic units are off 5 to 10 PPM over temperature & time (That's +/- 6,000 -13,000 Hz at 1.3 GHz) The FC1300 is accurate to within +/-13 Hz at 1.3 GHz 0-40 degrees C. Period Averaging, Time Interval, External Counter, Freq. Ratio, 4 Gate Times FIVE YEAR WARRANTEE REG. $599.00 Save $100 on FC1300 Laboratory Performance Stabilized Oven Osc .001 ppm All New ITC Low High Performance Oscilloscopes Cost TAKE ADVANTAGE 25 MHz Scope 40MHz Delayed Sweep Scope Call 800-566 -1818 Model ST3304 otoy $349.95 Model ST3315 only $569.95 Free 1995 Catalog

www.americanradiohistory.comAmericanRadioHistory.Com CELLULAR SOFTWARE AND MODIFICATION GUIDES i i Call Spy Supply for all of your Cellular needs!

We Carry:

We have the Motorola CELLULAR SOFTWARE new Software (We have the software to do New Motorola Phones) and Cables

CELLULAR CABLES (For the Motorola, Panasonic, and Nokia Phones)

CELLULAR MODIFICATION GUIDES (Covers all cellular manufacturers)

CELLULAR PHONES (We carry a complete line of cellular phones) FREE TECHNICAL SUPPORT! SPY SUPPLY Don't Get We now offer Cellular Find out why the Phones cloned with your Ripped Off! CIA - FBI - DEA - existing number! Buy a SECRET SERVICE Have handheld, transportable Before you buy our ordered from our catalog or car mounted phone competitor's manual, To receive yours, send $5.00 to: ready SPY SUPPLY to go and have call and ask if they offer 1212 Boylston St. #120 only one monthly bill! FREE TECHNICAL SUPPORT Chestnut Hill, MA 02167

SPY SUPPLY, 1212 Boylston St. #120, Chestnut Hill, MA 02167 (617) 327 -7272 Sold for educational purposes only

112

www.americanradiohistory.comAmericanRadioHistory.Com There's No Easier Way to TROUBLESHOOT AND REPAIR Your Electronics! 900-PAGE, MODULAR FORMAT It's easy, fast and rewarding to do it yourself with the Electronics Repair Manual! MANUAL TROUBLE ANALYSIS FLOWCHARTS Ns VCRs SCHEMATIC DIAGRAMS HANDS-ON, DETAILED, Electron¡ Hi-Fi Stereo TROUBLESHOOTING Repair INSTRUCTIONS Repair Electronics Amplifiers a. Manual "HOW TO" PRIMER FOR TEST EQUIPMENT Manual SUCH AS Turntables OSCILLOSCOPES, Repair Instructions Specific Diagrams FREQUENCY Basics Schematic Electronic Repair Indices COUNTERS, AND Speakers Equi Component/Manufacturer Tools and Test and antenance VIDEO ANALYZERS Troubleshooting Shortwave SAFETY PRECAUTION CHECKLISTS

Radios COMPREHENSIVE REPLACEMENT PARTS Camcorders LISTS PREVENTIVE Tape Decks MAINTENANCE TECHNIQUES

CD Players. DIRECTORY OF MANUFACTURERS Walkmans,

AM & FM 30 Day Free h'ial Order Form Yes, Please rush me my copy of Electronics Repair Manual for

Receivers only $59.95 ( I may take $10 off the price when I enclose my check or credit card authorization with my order within the next 30 days. PC Systems Plus, I get free shipping and handling!) I understand that if I am not satisfied I may return the book within 30 days for a full 100% refund of the purchase price. Automobile My payment of $59.95 is enclosed ($49.95 when ordering within the next 30 days.) Sound Systems vim. ' Check enclosed. Optional express delivery (available in U.S. only). Enclose an addi- PC Peripherals tional $10.00 and we'll guarantee delivery within 5 business days from receipt of your order (prepaid orders only). Telephone

Creml card no

Systems ( exp,at. Date Daytime phone no. Fax Machines Signature Bill me later for $59.95 plus $6.50 shipping and handling, subject to Home credit approval. Signature and phone number required to process your Electronic order. P.O. Box addresses must be prepaid. Mr./Mrs./Ms. Appliances Company

Address Keep Your Skills Up -to -Date! City State Zp The Electronics Repair Manual will be a valuable reference for years Shipping and handling to Canada. $10 (U.S. moer y). Overseas. $15 (foreign orders must be prepaid). to come. Supplements, each containing 140 pages, add new repair CT residents add 6 °0 sales tax. Supplements will be sent 0 -5 Gres a year on a fully-guaranteed. 30-day insights into new technologies, diagnostic and repair siat basis. They may be cancelled at any time. projects, valuable 31171 techniques, and more schematic diagrams into your manual. Just $30 MAIL TO: WEKA Publishing, Inc. each plus shipping and handling. Supplements are sent 4 -5 times a 1077 Bridgeport Avenue, Shelton, Connecticut 06484 year and are fully guaranteed. Return any supplements you don't want 1-800-222-WEKA FAX: 1-203-944-3863 113 within 30 -days and owe nothing. Cancel anytime.

www.americanradiohistory.comAmericanRadioHistory.Com MIRACLES NEVER CEASE

MICRO TX2000 KIT VFC400 VHF/UHF FM VOICE TRANSMITTER KIT -SMALLEST 120 MW FM VOICE/PHONE TRANSMITTER Agree -SMALL SIZE 1- 7/16" z 21/32" cnpin.Hry B ONLY 55995 -88- 110mhz ON ANY BROADCAST RECEIVER -ROCK SOLID TUNING, DOESN'T DRIFT -5 MIN. ASSEM., HEAR A WHISPER UP TO 2 MILES S9995 -SMT PARTS PREASSEMBLED 444 -INCLUDES TXMTR. MIC. ANTENNA, BATTERY CLIP, TUNING TOOL, AND INSTRUCTIONS -SMALLEST 400 MILLIWATT VOICE TRANSMITTER ANYWHERE! (1.5" x .56 ") -RECEIVE ON ANY SCANNER OR VHF/UHF SURVEILLANCE RECEIVER VOICE SCRAMBLER/DESCRAMBLER KIT -RELIABLE CRYSTAL CONTROL OSCILLATOR -5 MILE RANGE (OR BETTER!) -WORLDS SMALLEST AUDIO SCRAM./DESCRAM. -SUPER SENSITIVE OP-AMP PICKS UP SOUNDS AT WHISPER LEVEL $6995 -TALK IN PRIVACY ON AUDIO, SPKR. OR MIC LINE -LINE LEVEL AUDIO INPUT FOR DATA, STATION ID, OR INTERFACE TO OUR POPULAR VOICE RECORDERS -HEAR THOSE GARBLED SCANNER VOICES -SIMPLE 5 MINUTE ASSEMBLY, ALL CHIP COMPONENTS ARE PRE- ASSEMBLED 2 FOR -SMALL SIZE 1 "x7/8 "x1/4" -CUSTOM FREQUENCIES AVAILABLE FOR LAW ENFORCEMENT -CRYSTAL CONTROLLED DIGITAL SPEECH INVERSION -INCLUDES TRANSMITTER, CRYSTAL, BATTERY HOLDER, MICROPHONE. ANTENNA, & INSTRUCTIONS $129.95 -7 -15 VOLT DC SUPPLY -CHANNEL A) 146.565 MHZ B) 149000 MHZ (SELECT ONE WHEN ORDERING) -LOUD HALF WATT AUDIO AMPLIFIER -EXCELLENT AUDIO QUALITY -INCLUDES FULL DOCUMENTATION MICRO -4 MULTI -MESSAGE VOICE RECORDER -DUPLEX SCRAMBLE B DESCRAMBLE AT THE SAME TIME -EXACT SOUND REPRODUCTION

«TCCC?21A -SMALL SIZE 1 -3/4" z 1 -5/8" 8aß' . MICRO 1.2 VOICE RECORDER -NEW EDGE CARD DESIGN IS e- STANDARD .100 SPACING -4 MESSAGE MAX. UP TO 20 SECONDS -SMALL SIZE 1 -1/4 "x15/16 "x1/4" HttltRtltttt -HUNDREDS OF APPLICATIONS w -LED INDICATES RECORDING IN PROGRESS ; $69" -EXCELLENT AUDIO DUALITY -6 VOLT INPUT ONLY DRAWS .5 uA STANDBY -60 SECONDS REC/PLAY tr -7 -13.8 VOLT REGULATED INPUT 61 30ma -8 OHM SPEAKER OUTPUT xr t"r -8 OHM 50 MILLIWATT SPEAKER OUTPUT -7 -15 VOLT DC SUPPLY t Ht -LINE LEVEL AUDIO OUTPUT (VARIABLE) ,- -FULLY ASSEMBLED (NOT -100 YEAR MEMORY WITHOUT POWER 9Yt 'ti -1' A KIT) -INCLUDES MIC. SWITCHES AND FULL -100'S OF APPLICATIONS, ALARMS, PRODUCT DISPLAY, DOCUMENTATION NOTE PAD, HAM, CB, MUSEUMS, ETC -SWITCHES. MICROPHONE, 8 INSTRUCTIONS INCLUDED MICRO 2B VOICE RECORDER ONLY 95 MICRO 2B FEATURES $89 COMING SOON $10995 SAME AS 1.2 PLUS -MULTI MESSAGES (UP TO 600 HEM.) -SMALL SIZE 1- 5/16 "xl- 5/8 "x1R" MICRO -3 -VARIABLE AUTO PLAY TIMER GF2ELCD -5 VOLT KEY OUT DURING PLAYBACK RECIPLAY UP TO 4.5 MINUTES UP TO 1800 MESSAGES (NO DIODES ORDER BY PHONE OR MAIL C.O.D. CHARGES APPLY 1145 CATALYN STREET MESSAGE CUEING (FAST FORWARD) IN U.S.A. ADD $5 FOR S &H NYS RESIDENTS ADD SALES TAX SCHENECTADY, NY 12303

TECH. FAX: 518- 381 -1058 TO ORDER: CALL 1- (800) -588 4300 -E, TECH. SUPPORT: 518 -381 -1057

Motion Control System C249.9s

Includes Stepper Controller Card, I2VCT Transformer, (2) 4 Phase Stepper Motors, Easy to use I.B.M Software! Connects to any I.B.M. Compatible LITT Port (1,2,3)....

Cable TV Descramblers ' Converters Absolutely The Lowest Prices!

All Major Brands *#1 In Customer Service

30 Day Money Guarantee - 2 Year Warranty Call For Price Quote. Please Have Make And Model

* Nothing more to Buy! Number Ready When You Call. * Easy Installation 15 minutes or Less! No Tools Required! Design Robots, Plotters, Laser Systems! Drives (2), 4 Phase Stepping Motors! Frequent Buyer And Quantity Discounts * Bi- Directional 8 Bit Read and Write Port! * Board Addressable, 16 Possible Choices! Fits in Standard 19" inch Card Rack!

With Additional Cards Control 32 Motors on 1 LPT Printer Port! Features Include: Variable Speed, Step, Range, Direction, and On'Of Control! " Free QBasic & Gwbasic Source Code $ 59.95 value! I 8002037077 Send Check or M.O. to: The C.W. Outlet CYBERMATION Call Us Today! 9030 West Sahara - Las Vegas, Nevada 89117 "Intelligent Conbvllerx" Tel (714) 879 -2000 Visa/Master Charge Accepted 1943 Sunny Crest Dr., Suite 288, 114 Fullerton, CA 92635 " Add $12.00 MN; CA residents please add sales sax

www.americanradiohistory.comAmericanRadioHistory.Com AMREL Offers Lowest Prices & Best Warranties on DC Power Supplies ANYWHERE!

AMPEL Offers Superior Analog Power Supplies Starting as Low as $149.00 Low Output noise rating less than 0.3mV. Line/load regulation rated at low 0.01% + l mV. Transient response time of 5011 Sec. Overload protection, and Output enable/disable. Coarse and fine voltage /current adjustment. Auto series/parallel operations for triple output supplies.

AMPEL Offers Features And Prices on Digital Power Supplies That The Competition Can't Beat! Microprocessor controlled. User friendly keypad data entry. Low output noise rating less than 1mV. Line/Load regulation rated less than 2nW. Output enable /disable and Power off memory. Optional RS-232 interface capability.

Model LPs - I t) I I.1'4- 102 us-103 LPs-104 LPs-105 LPS -]106 LPs -301 LPs-302 LPs -303 LPs-304 LPs -305 Rating 304/IA tuv?2n 30V /3A +30V/1A +30V /3A 60V /1A 15V /2A(H) 15V/4Aí1-) 30V/34 +30V/1A +30V/2.5A 30V /lA -30V/3A 30V /IA(L) 30V /2AÍL) -30V /lA -30V/2.5A 3- 6.5V /3A 3- 6.5V/3A 5V /2A 3.3 -5V /3A List Price $195 $225 $295 $395 $495 $245 $249 $299 $369 $399 $599 tiac Price $149 $170 $199 $375 $469 5219 $199 $285 $350 $579 5569

caii 1100138-2020 USA

P-ocüaa I a.inntun,:,1 Inc 8931 Brookville Road Silver Serine Mary aryl 2097 0 Fex: 800- 54°nn=F,

CIRCLE 46 ON FREE INFORMATION CARD ATTENTION CABLE VIEWERS CABLE VIEWERS.. .get back to your BASIC Cable Needs Call 800 -577 -8775 For information regarding all of your BASIC cable needs.

5 GOOD REASONS TO BUY OUR FAR SUPERIOR PRODUCT PRICE EFFICIENT SALES AND SERVICE WE SPECIALIZE IN 5, 10 LOT PRICING ALL FUNCTIONS (COMPATIBLE WITH ALL MAJOR BRANDS) ANY SIZE ORDER FILLED WITH SAME DAY SHIPPING

We handle NEW equipment ONLY - Don't trust last year's OBSOLETE and UNSOLD stock! BAS C COMPETITIVE PRICING- DEALERS WELCOME ELECTRICAL HOURS: Monday -Saturday 9 -5 C.S.T. St SUPPLY It is not the Intent of B.E.S.W. to defraud any pay television operator an we will not assist any company or individual In noting the same. WAREHOUSING 'Refer to sales personnel for spec.flcstions. CORPORATION P.O. Box 8180 Bartlett, IL 60103 in 800- 577 -8775 115

www.americanradiohistory.comAmericanRadioHistory.Com WE ACCEPT VISA. MC. MO. COD SHIPPING & HANDLING EXTRA VISA FM TRANSMITTERS SATISFACTION GUARANTEED! BUY WITH CONFIDENCE FROM XANDI ELECTRONIC KITS AND MORE 30 -DAY REFUND POLICY TECH SUPPORT NUMBER (602-894-0992) Tunes 88 -108 MHz. Miniature photo battery mounts right on Up to 1 mile range. Smallest Phone transmitter anywhere! circuit board. (Included) Powerful 2 stage audio amplifier. Miniature photo battery mounts Tunes 88 -108 MHz. Tunes 88-108 MHz. batteries required, Sensitive, picks up sounds at the nght on circuit board. No powered by phone line. level of a whisper. Up to 12 mile range. ft:Yu Transmits at 143 MHz. Up to 1/4 mile range. Up to 1 mile range. Sens4re 2 stage audo amplifier, picks up Amazing audio sensitivity, picks up 40 Attach to phone line anywhere in Requires 9V battery. Not incl.) sounds at the level of a whisper. sounds at the level of a whisper. house, even inside phone. SUPER -MINIATURE FM TRANSMITTER MICRO -MINIATURE FM TRANSMITTER CRYSTAL CONTROLLED FM TRANSMITTER SUPER -MINIATURE PHONE TRANSMITTER Super FM small transmitter. Use with any FM broad- Including the battery. this is the Worlds smallest FM Including the battery, this is the Worlds smallest crystal con- Worlds smallest FM phone transmitter. Use with any cast receiver. Easy assemble, to all chip (SNIT) parts transmitter. Use with any FM broadcast receiver. Easy trolled FM transmitter. Transmits to any scanner type re- FM broadcast receiver. Easy to assemble, all chip com- are pm- assembled to the circuit board. to assemble, uses pre -assembled circuit board. ceiver. Easy to assemble, uses pre -assembled circuit board. ponents are pre -assembled to the circuit board. XST500 (E -Z) Kit S44.95 XWB1000 E -Z KIT S49.95 XTL1000 E-Z KIT S69.95 XSP250 E-Z Kit S34.95 Dial your phone from Transmits a continuous beeping tone. anywhere Uses sensitive microwave tran- Use with any FM broadcast receiver and listen to the sounds in- Adjustable from 88 sistor amplifier Hear every soundnanentiretouse! tom. sde your home. to 108 MHz. Covers 1 to 2,000 MHz. Up to 1 mile range r. Two digit Touch Tone code Up to 1 mile range. Compact hand held unit. for secure operation. Powerful 2 stage audio ` FM Includes minatore Works with any bud speaker for amplifier. TELEPHONE SNOOP broadcast receiver. audio indication of detected signals. Call home from anywhere, enter a two digit security code, TRACKING TRANSMITTER MINIATURE FM TRANSMITTER and hear the sounds in your home . Automatically turns SUPER SENSITIVE BUG DETECTOR on Only 0.7 by 2.4 inches, the XTR100 without ringing the phone, verifies code, then acti- operates at voltages of 3 to When the XBD200 intercepts a signal in the 1 to 2,000 MHz The XFM100 has a super sensitive microphone and is ca- vates for one and a half minutes. 18 Volts is ideal and for use in locating lost model rodarls, bi- range, lt emits a growl that increases to a high pitched squeal pable of picking up sounds at the level of a whisper and cycles, automobiles, games of hide and seek and contests. transmitting them to any FM broadcast receiver. XTR100 C Kit $33.95 XFM100 C Kit S32.95 Digital voice changing male to Digital voice changing: male to fe- Uninterrupted 800 to 950 MHz Transmit high quality stereo to any FM - female, female to male. adult to male, female to male, adult to child, coverage. yR.; stereo receiver. child, child to adult. child to adult. / Works with any scanner that Built-in output level monitor for Maintain anonymity on any call. , - Use with any modular phone. can receive 400 to 550 MHz, quick and easy tiring. Button for normal operation. 16 levels of voice masking. -'' deal for use with personal CD 800-950 16 levels of voice masking, ' MHz SCANNER CONVERTER player. V Connects between handset and phone. If your scanner can receive 400 -550 MHz, just add the FM TRANSMITTER VOICE CHANGING TELEPHONE VOICE CHANGING ACCESSORY XLC900 for uninterrupted 800 -950 MHz coverage. It STEREO Transmit full -bodied Hi Fi stereo to any FM stereo receiver. STOP THOSE ANNOYING TELEPHONE CALLS! STOP THOSE ANNOYING TELEPHONE CALLS! converts all 800 -950 MHz signals to 400 -550 MHz so your scanner can receive them! Add our custom case Separate left and right inputs and gain controls. Includes Sound older and tougher when you want to. Not a kit. Sound older and tougher when you want to. Not a kit. kit for that 'Professional' look. an output booster stage for greater range. Fully assembled. Single phone operation only Fully assembled. Use with single or multi -line phones. XLC -CASE KIT $13.95 XFS -CASE KR $13.95 TRANSITION 2000 $89.95 TRANSITION 2001 S59.95 XLC900 C KIT $49.95 XFS108 C KIT $41.95 acitisno T S°vra9 tive p'6Gc .nuce IA91 TOLL FREE ORDER LINE SEND MAIL XANDI ELECTRONICS ELEG TRONZCB 1- 800- 336 -7389 ORDERS TO: BOX 25647 1270 E Broadway Rd. # 113, Tempe AZ 85282 ASK FOR FREE CATALOG OF OUR PRODUCTS TEMPE AZ 85285 -5647

CIRCLE 134 ON FREE INFORMATION CARD Make Digital Storage Oscilloscope your projects For $169.95 ? ?? speak for themselves... And much, much more! Ours dot O -Scope I turns PC -ATs into DSO, spectrum analyzer, frequency counter, DVM. DC -50KHz DIGITAL VOICE RECORDERS ...... Record up to 218 seconds 111f=I.l.. 1 to 8 messages Iwiil High quality speech 12 bit Switch -closure actuation tSinewave Sweep Sample rates up to 20Khz On -board backup Actual O -Scope Direct speaker output Signal Traces Wide operating range Small size 2.6" X 2.6" Made in U.S.A.

MODEL Audiode218 Call or write for more information Spectrum OEM price and delivery available Custom designs and enclosures Single unit price $149.00 plus s +h For Orders and Inquiries Call: 1- 800 -980 -9806 Quantity pricing as low as $99.00 For Technical Assistance: 1- 713 -777 -0401 Allison Technology Corporation 402 Riley Road, New Windsor, NY 12553 116 8343 Carvel, Houston, TX 77036 (914) 564-5347 FAX and BBS 1- 713- 777 -4746 Specifications and price subject to change.

www.americanradiohistory.comAmericanRadioHistory.Com PE MARKET CENTER CABLE TV CLASSIFIEDS DE SCRAMBLERS REPAIRS-SERVICES Best Wholesale Prices in the U.S.A.! TEST EQUIPMENT: repair including power supplies and other measuring devices excluding 50+ oscilloscopes, power supply repair of computer 1 -4 5 -9 10-19 20-49 equipment, call (812) 295 -4240. For Jerrold Systems TNT+ 59 55 49 45 40 BUSINESS OPPORTUNITIES 55 49 44 39 34 START your own technical venture! Don Lan- Stealth+ caster's newly updated Incredible Secret Money 49 39 35 32 30 Machine Il tells how. We now have autographed FTB3 copies of the Guru's underground classic for Atlanta Systems $18.50. SYNERGETICS PRESS, Box 809 -C, For Scientific Thatcher, AZ 85552. (520) 428-4073. Visa/MC. M80 69 62 55 45 40 GREAT EXTRA income! Assemble craft products at home. Easy /fun! Program guaranteed! Call: 1 SA3 55 45 40 36 33 (800) 377 -6000 ex7930. EARN COMPUTER $$$$$ Start a home comput- For Pioneer Systems er business or enhance ANY business with computer business needs. Complete packages! Super -PIO+ 69 62 55 45 40 Manuals, video tapes, business software, turn- key computer systems. FREE brochure. The Harsin Company, 8681 -F West New Bethel Road, Panasonic Converter Lexington, IN 47138. (812) 866 -4076 (24 hr. message) TZPC1003 75 67 62 59 57 MAKE $75,000 to $250,000 YEARLY. Repairing all kinds IBM monitors. Successful home based business, anywhere. Telephone required. Details: 1- 800 -818 -9688 USA $3.00 cash (no checks), Dealerships: Canada -all foreign countries: $85.00 for U.S. Cable TV Inc. M -F: 9-6 EST application- brochure. Randall Display, Box 4100 N.Powerline Rd., BJdg.F4 Pompano Beach, FL 33073 2168H, Van Nuys, CA 91404. U.S. Cable will only sell the cable equipment to authorized cable subscribers. It is illegal to operate this equipment without paying for the basic and the premium services. U.S. Cable will not sell to anyone who will not comply with Federal and State laws. No Florida Saks. PUBLICATIONS HISTORIC AND Classic hardware support magazine. The Computer Journal provides how -to information on keeping S -100, Kaypro, Z80, 6809, SURVEILLANCE CP/M, and PC /XT systems running. Over TEN years of hardware, software projects. 6 issues FM TRANSMITTERS MINI (KITS) $24.00. Free 1 (800) 424 -8825. TCJ, PO sample. 3 -VOLT FM XMTR, up to 300 ft. indoors, 1500 ft. outdoors Box 535, Lincoln, CA 95648. PHONE XMTR, range to 500 ft., uses phone-line power Sound- Activated XMTR, range to 500 ft. 2 -STAGE XMTR, 9-Volt, very powerful

All above require simple soldering at 2 to 4 places. - If you are not getting $29.95 ** this catalog you are MASTERCARD AND VISA are now accept- TELE FM WIRELESS MONITORING SYSTEM. missing Out on some ed for payment of your advertising. Simply (Kit) $99.00* of the best deals in complete the Classified Ad order form and TELE CALL FORWARDER. Transfers incoming electronics today! We have thousands of we will bill you. calls. $99.00* items ranging from unique, hard -to -find incoming number. CALLER ID. Registers parts to standard production components. $99.00* Call, write. or fax today to start your free TEL REGISTER WITH PRINTER. Records dialed to the most unique catalog in number, duration, and prints record. $139.00* subscription the industry, filled with super values on 12 -HOUR LONG -PLAY RECORDER. Modified Panasonic. Records 6 hrs. on each side of 120 surplus electronic and hobbyist type Yours for only tape (supplied). Compatible with VOX and Tel items. If you have a friend who would $350 Rec Adapter. $119.00* like to receive our catalog, send us their VOX VOICE- ACTIVATED SWITCH. Makes re- name and address and we will gladly Prices includes self- activating with voices or other corder forward them a complementary 100 page sounds. $28.50 ** shipping! catalog. TELE RECORDING ADAPTER. Records incoming and outgoing calls. $28.50* Why pay more'? Call today. HAVE A THOUSAND YUCKS FOR ONLY TELEPHONE SCRAMBLERS. Over 4,000 THREE AND A HALF BUCKS! That comes separate codes. $199.00* to one -third of a cent per laugh. Electronics VOICE CHANGER. Changes man's voice to Comics is a compilation of over 125 riotous, lady's and vice versa. $49.00 ** and phenomenal cartoons that outrageous For Shipping & Handling add *$5.00 and *$2.00 per item. appeared in Popular Electronics and Elec- residents add sales tax. Mail Order, VISA, M /C, COD's Colo. Fax Order Line tronics Now. Only $3.50 -price includes o.k. Inquire for dealer prices. Free catalog. 340 East First Street shipping. Claggk, Inc., Reprint Bookstore, MUCH, MUCH MORE - OUR 25TH YEAR! Dayton, Ohio 45404 1- 800 -344 -6324 P.O. Box 4099, Farmingdale, NY 11735- TOLL FREE 1- 800 -926 -2488 payments in U.S. funds. Sorry, no 0793. All A.M.C. SALES, INC. orders outside U.S.A. and Canada. Check or 193 Vaquero Dr., Boulder, CO 80303 Order Toll -Free money order only -send no cash. NY state Tel: (303) 499 -5405, Fax: (303) 494-4924 117 residents add applicable tax. MAO4 Mon. -Fri. 8 a.m. -5 p.m. Mtn. Time 1- 800 - 344 -4465

CIRCLE 140 ON FREE INFORMATION CARD CIRCLE 149 ON FREE INFORMATION CARD

www.americanradiohistory.comAmericanRadioHistory.Com STOPPING POWER METERS As reported on 9 ' mules : How torten can slow down - even slop - waffhour meters - rlll i0lr1 whlle loads draw lull power! Device simply plugs into 1' scribes meter crepal !overload droop, etc. Plans $29 i. SI(,1'J J External magnetic ways (applied to the meter flsel) to slow down and stop watthour meters PCB Artwork CON B U M E R T R O N I C S whsle drawing full loads. Plans. $19. MUM 2011 Crescent Dr., P.O. Drawer 537 METER51 How watthour meters work, calibration, Alamogordo, NM 88310 error modes (many), ANSI Standards, etc. Demand and FTlittards Made Easy! Vice (505) 439.1778, 439.8551; Polyphase Meters. Experimental results to slow and sto. meters b others . 19. An 2 38. All 3 59. BAM - BPM MST, Mon - Sat Pax: (505) 434.0234, 434.1778 (orders AUTOMATIC TELLER MACHINES PRINTED CIRCUIT DESIGN SOFTWARE Only; 11 you get voice, enter 'ral t et t any time); 24-hr ATM crimes, abuses, vulnerabilities and defeats ex- for Frew Tech_Hup ort (relates directly to your posed! 100+ methods detailed, Include: Physical, Reg. order or prospective order : Tues. and Thurs. only. E, cipher, PIN compromise, card counterieltlng, mag- Layout - Autoroutinq - Schematic spot ng,pIn false front, TEMPEST, Van Eck tap 10%1111gDjrdert S100í IMe_01LpyeLS200.f spoofing, Inhere super-cool, vibration, rmea Mgh Add $5 total SM (US. Canada). All items In stock. VISA, 1 voltage - others. Case hrstolabe law, countermeasures, * Supports all Video Modes including SVGA MCard OK. No CODs or 'bill mg's. New NO._yy (200+ of- detailed security checklist labeled Internal photos, fi - fees) $2 Warder, $5 wit (check or MO - NOJzeLCatalog_ ores. ATMs contain up to $250,000 in cash! Recent HO dealers. Since 1971. As seen on CBS '60 Minutes' * Copper Flooding for Ground Areas $350 000 ATM crime scree still unsolved! Forbes, etc. By John Williams - loaner Lockheed Senior $39. Engineer, NMSU Computer Science Professor, NIH Health CREDIT CARD SCAMS * Mirror Imaging for Laser Physicist. MAC Output Wanted; 9 1lcl. PC366, bener - buy, trade. Cardholders, merchants, banks suffer Billions In A11 software supports all IBM -PC corm losses annually because of Credit card fraud. Describes * Circuit Simulation Programs patibi 88 systems (8088 Pentium) every known means of credit card fraud and scams. available Protect ourself? 29. Off -The -Shelf HARDWARE * NEW -WINDOWS tin versions 'an c ys ems, la a ar, ea'e "r ens CONS SCAMS & SWINDLES ATM2, RF/ENNRadavtlitrasonicr1R Jammeru'Delec- Cons E scams and related swindles fleece Americans of * NEW - DOS versions Iorslieceivers'Xmitlers, Securlly'Surveillance De- $100+ Billion per year) The most comprehensive sur- vices, EM LabWeaponnvtountermeaaures, Neur- rival manual on cons 8 scams of all kinds - from the ophonsltllalNeronymuwResonant Crystal Radios- classic to hi-tech. Details on 1005 and their many varia- * FREE - Heat Transfer Film with Order kea, Voice Disguiser:, Phone Color Boxes, Line- lions and countermeasures. Protect ourself! 39. man's Handsets, DTMF Decoder, Bug & Tap Detec- STEALTH TECHNOLOGY * Great for All Printed Circuit Projects tor/Blaster, Cariackl(Idnap Follar, Nearing Assistor, Police radar Is fascinating! It also has error rates of 10- Shriek Module, TENS, 6th Sense Communicator, 20 %1 Every known error mode - stealth method and ma- Subliminal MI :et/Amp, Download Levltator, Vortex Generator, teniui used to minimize radar reflections - tactic and Demos from BBS (205)933 -2954 Noise Cancelling System, Unknown Presence De- strategy to fight unjust radar tickets at cost you lector, Electronic Dowser, Bacteria Detection Kil - $100s in insurance and risk cancellation methods to many, many more devices. See our New Catalog. detect and am siinals - full described) 29. PCBoards Layout Only ... $99.00 CELLPHONE MODIFICATIONS & SECRET SURVIVAL RADIO Layout for Windows tm starts at ... See our Catalog for our inlamous ceiiphone moddica- splimum survival and security radio equipment, me, - $149.00 lion guide ($69) - detailed, comprehensive, covers all ods, freq allocations and volcetata scramblingbncod- makes - 10 times more Info than competitor's 'guide). ing. Includes small receiverstnansmitters, telemetry, an- Call or Write for Full Product Line, Prices d Demo Packages (Do Special Projects (below) for up -lo -date hardware' lesna optimizations, remote monitoring and control, se- software . curity, surveillance, and ultrasonic, fiber-optic and kdn- PCBoards SPECIAL PROJECTS red commo. 70+ circuit 'tans tables. $20. (800) 473 -7227 We deslgnbuildbblaintepaivtnodify- tnaintaintonsufl on HIGH VOLTAGE DEVICES 2110 14th Ave. South Fax (205) 933 -2954 any devlcstystemgrocesssqrrdject - electdcalblectronkc HV devices plans: Stun un, Taser, Prod, ana, Birmingham, AL 35205 phonstomputeetnechanicalbpflcaláutomotive for bust- Flasher, Blaster, Zapper, AudIoAFAiadar Jammer, Phone (205) 933 -1122 nessbersonaltnvention need. Confidentiality guaranteed. Jacob's Ladder, Plasma 8 Van de Graaff Gene., Fence Describe and Include 530 pre -engineering lee (does not Charger, Geiger Counter, Ozone Gen., Fish Stunner, obit i ale ou . Time and cost estimates In 7.10 da s. Plant Slim. Kiriian, morel All .fans for on S29. The HACKER FILES UNDER ATTACK! Compilation of 1005 (In of the best articles written ectromagne i r n e none an. Iectraele ASCII) by top hackers S. phreakers. Covers every major Weapon Attacks cause: Cancer, birth defects, and pro - lo.ic in hackerdoml 3 HD Disks* S59. found psychological, neurological, cardiovascular and VOICE MAIL HACKING immune system disorders! Destructive to people, ant- mats, p!ants, equipment! Includes CASES OF ow 'o ce ' a :ox ' ' ; sys ems are use. an I e ACIUAI Investigated)! Includes how to verity specific ways they are hacked. Includes ASPEN, MES- EMTSACKS (we CABLE TV SAGE CENTER, BIX, GENESIS, EZ, SYDNEY, PHONE and pinpoint EMI and electronic attack sources, and spe- MAIL. AUDIS, CINDY, CENTAGRAM, SPERRY LINK, cllk countermeasures. $29. £M.DRAIHBJ.ASTn Tutorial for RSVP, etc. Absolutely required for all users, sysops and ill: and plans powerful ELECTROMAG- Universal Descrambler securi .ersonnell $29. NETIC WEAPONS and LAB DEVICES. Optimum circuits, tregs, waveforms, duty cycles, Intensities. Thorough. NEW PRODUCT PBX HACKING $29. Both S49. 1,000s of PBXs are hacked to the tune of Billionsyrl RADIONICS MANUAL While 'VOICE MAIL HACKING' details how VMSs are 1NIVERSAL 5000 $199.95 Exciting electrical, electronic, electromagnetic therapeu- hacked for 'oho' and profit - Including VMS methods ti c, diagnostic & preventi ve devices (mostly experhnen- tor hacking PBXs themselves - 'PBX HACKING' ad- Our fully assembled is . product factory tested dresses ALL issues relating to PBX hacking, Including tat) History, descriptions, plans (dozens), avallab9ltks and of While countermeasures! Can your business or agency afford a Radlonics Devices from early to modem. drugs 590,000 phone fraud loss (the average loss due to cost S Hundreds, electricity costs pennies! $29. HEAL GUARANTEED to work on your system. THYSELF: Plans for 3 major electronic therapeutic hacked PBXs ? As descdbed In Forbes Ma ' awe. $29 PHREAKING ANI devices of .es a..rovedb FDA. 19. Both 39. MODEL 4000 KIT $ 79.95 CALLER ID & TECHNIQUES s on ow they wo an..ozens o eective ways CRYPTANALYSIS Five menu .COM of defeating Caller ID, ANI, 69. '57, and Call Blocking powerful -driven cryplo programs (in The 4000 KIT comes with all the electronic parts . AS to and 67. Also describes Caller ID, Orange, Belge, and source code) analyze, decrypt 'secure' cl- Waked -ou( examples. Recommended b( CheeseCetai and CF Boxes, ESS, 557, E -911, various phertexts. CLASS services, CWA, NON PUB DA, CAMA, DNR, prestigious'Computers 8 Security. Manual + Disk and our Cad designed PC board. We provide parts 800 -ECR Olverters Extenders Centres - more $29. Be and PHONE COLOR BOXES B an ORDER of the MAGNITUDE list, full schmatic, wiring diagram and tutorial. The most comprehensive, hard -hieing, hl-tech cur - Dozens phone color boxes described - many circuits. vivai book ever veillent Topics include electronics, Plus Call Forwarding, Canterencing, Phreak Hlsiorrvy, MODEL 4000A Enclosure energy, weapons, concealment revenge, $ 44.95 Glossary, Dlrtere,Dinners, Extenders, Loops, REMOBS, alarms, etc to suive today's dangerous world. We all Bridging Heads 8 Cans, Optocom, 3rd Party and many face increasingly financially and physically brutal times! The 4000A Enc. Package will provide the hobbyist, other non -box methods - more. $39. Field- expedient use of technology in various threat and ROBOFONE AUTODIALER connect environments and scenanos. $49. who has our4000 Kit, a custom enclosure, AC Powerful, versatile, menu -driven Wargames autodi- ROCKET'S RED GLARE aler lets you dial any quantity (up to 10K) or mix of local, ow to 'coign an. i w . so a -prope an ama cur long distance numbers in any order, over any length of adaptor and finish accessories to enclose their kit. survival rockets. Emphasis on formulation, manufacture, time, whether busy or answered (your choice) and lop Installation of propellants, motors, Igniters, etc. includes the times, commands and results to monitor. printer list of commonly available materials, and he design of and -or disk. Quick -dial directory of up to 600 numbers. launch pads and test beds and their electronics. $29. BUSY redial options. Direct modem command and con - How firecrackers (M -80s, blockbust- MODEL 4000 And troi. All Result Codes, Including VOICE and RINGING. FIREIN9HKSI 5000 Features ers, cherry bombs), small rockets, volcanos, fountains, Optional shell to terminal pro.ram upon CONNECT. Exit sparklers and safety fuses are made and colored. to menu or DOS for batchln.. Manual + Disk* $29. Simple, cheap, common Ingredients. $9. Both $36. The latest in Video Amplification Technology. COMPUTER PHREAKING _ r escn.es n .etas ow computers pene ra e eac of er, New clocking circuits to stabilize Legendary eau ies cope ra, a en o roy, N color and and how VIRUSES, TROJAN HORSES, WORMS, etc are others augmented beauty with natural preparations. De- Implemented. Dozens of computer crime and abuse scdbes In detail how many personal cam products (nc picture performance. methods and countermeasures. Includes disk filled with skin care, hair care, makeup, soaps, grooming prepare- hacker text files and uektes, and the legendary FLU - lions and fragrances) are made from sale, natural Ines- The most SHOT+ protection system (Ed. Choice, PC Magazine). advanced picture locking circuitry. pensive substances. For all skin colors, shades. Also in- BBS advice, password defeats, glossary - much morel dudes theatrical ceremonial wa 'alot makeu. 29. Manual + Disks* $39. Inverted Video Option is available. ULTIMATE SUCCESS MANUAL overworked, NO CONVERTER BOX is necessary. eves ropPmp on an compu er n eo sipna s usmq of office politics? Stuck a dead- endrlob? Cant find a an ordinary TV described in detail. Includes security en- Kb? Expect to be laid off, fired or transferred soon? dustry reports. Range up to 1 KM. Plans include both ?tieThe ultimate no- holds -barred, looking- aver -N1 Machia- The Halcyon Group 1- 800 -664 -6999 the Ceesumertronics and the original Top Secret Van vell!an techniques to find, obtain, optimize and keep top Eck designs! $29. 118 lobs, pay and benefits. THE RULES OF THE GAME FOR sold for educational purpoeee only A GAME WITHOUT RULES! From resume to CEO. $29. From Canada Call 1 -508- 643 -4102

www.americanradiohistory.comAmericanRadioHistory.Com A $3 Billion Forest Market in '94 Electra Voice Activated Inc. Home Automation Are you overpaying .. . The ultimate in luxury, security, safety, ... your cable company? convenience, and energy savings for new or existing homes! The ultimate Yo u are if .. . business opportunity of the '90s! ... you are leasing their Huge Untapped Market equipment. Incredible Profit Potential Forest Electronics, Inc. offers a complete line of Little or No Competition Protected Territories New Cable Decoders and Converters that Unique Products are fully Compatible with your cable system. Complete Training & Support All systems come with: Remote Control, & Simple to install and Use Parental Guidance Feature. Volume Control Free National Advertising is also available. No Experience Necessary All Equipment is fully guaranteed & comes For Free Dealership Brochure & Tape with a 30 day money back option. Call 24 Hours For More Information Call Us 24 Hours a Day At: 1- 80044HOUSE 800..332..1996 (512) 263 -5199 Fax (512) 263 -5499 FAX: 708 -860 -9048 Complete Dealer Package From $6900

., B SPICE B2 LOGIC for windowsTM and macintoshTM .: $149 o,,:. Simulation: Transient, DC Operating r Point, DC sweep, and AC sweep amit s-110 - Library: MOSFETs, BJTs, JFETs, op amps, & many more -r ., 'rvl Y Circuit analysis based on Berkeley SPICE r- Device & Model Property Editing ,,_fl. Flexible Visualization of Results: customized graphs and tables Why Design Circuits the Hard Way? B' Loct1: 3.0 $199 B2 SPICE v.1.1 and B2 LOGIC v.3.0 are the most powerful and affordable integrated EDIF File Format Output analog and digital circuit design, simulation, and analysis packages available. B2 SPICE Enhanced PI D Simulation Capture and B2 LOGIC neatly integrate the schematic editor, simulator, and graphics post processor. Subcircuit Pobing They are fully integrated and interactive and are extremely easy to use for Windows'^', Over 100 components available

Macintosh'", and Power MacTM Both B2 SPICE and 82 LOGIC are currently in use at over 100 major universities and many leadiig Fortune 500 companies such as The University h.I.h.crüoNN: Dtsu:N P U I. 11.F: $269 of Michigan, Stanford, AT &T, General Electric, and Hewlett Packard, to mention a few! Includes B2 SPICE and B2 LOGIC

Demo Disks Available Phone 313. 971. 4227 University & Student Prices Available Beige Bag Software Site Licenses Available 2000 Hogback Road Suite 2 Fax 313. 971. 3632 Ann Arbor Michigan 48105 E -Mail info @beigebag.com Dealer Inquiries Welcome Visa /Master Card Accepted

119

CIRCLE 161 ON FREE INFORMATION CARD

www.americanradiohistory.comAmericanRadioHistory.Com I F1.STEk Test & Measuring Instruments 20 MHZ, 2- Channel, OSCILLOSCOPE Az model #0S-622B AD 20MHz, Dual Channel 4 High Sensitivity 1 mV /DIV AD TV Synchronization AD Z axis input

AD ALT Triggering Function

AD Hold Off Function

AD Trigger Level Lock Function ,D CH 1 Output 4 Includes Probes (x1, x10) AD 2 Year Warranty Regular $499.00 Sale $389.95 800-638-2020 PRINT (ííiì Masre Care Products International l v 11 Test Instruments, Equipment, Tools & Supplies For Electronic Production, Maintenance & Service 8931 Brookville Road, Silver Spring, MD, 20910 * 800 -638-2020 * Fax 800 -545 -0058

CIRCLE 162 ON FREE INFORMATION CARD

Interactive Development Environments for the Microchip Technology, Inc. PIC family of PIC microcontrollers. Microsoft Windows 3.1 MDI Applications MiCrOVieWTM Simulation Environment Assemble!' Universal PIC Assembler

.. LI 1, .+H.k., wY x... w.i.,.la..luc. sy.wa,,.rwr,

n*1 ,,.,., á i41.. ».d,.»...... -q . .» ...

MICROVIEW''' is a full- featured simulation environmet t for ASSEMBLE! is a universal macro assembler for the the Microchip Technology, Inc. PIC 1605\ microcontrollers. Microchip Technology, Inc. microcontrollers. Assemble! Other simulation engines available. supports all of the Microchip device families. Features: Features: Integrated Programming Editor, Macro-Assembler Integrated Programming Editor, Macro -Assembler Simultaneous Multiple Device Simulations Bookmarks. Macro Key Recording, Search and Replace Graphical Timing Diagrams, Input Stimulus Generation Error Report, Listings, Context Sensitive On -Line Help Step. Register, Full Break Point Capability COD File Format, INHX8S, INI-IX8M, INHX16 Direct Download to PICSTART. Compatible with Direct Download to PICSTART. Compatible with PICMASTER. and the Parallax Downloader PICMASTER, and the Parallax Downloader

MicroViewTM $149.95USD VISA/MC Assemble!T"r $99.95USD VISA/MC TRISYS Send check or Money Order. VISA/MC Accepted, Company Purchased Orders Accepted, Shipping and Handling Included. TRISYS, Inc. P.O. Box 11087 Glendale. AZ 85318 -1087 USA PH: (602) 581 -1760 FAX: (602) 516 -0582 120 [PIC, PICMASTER, and PICSTART are trademarks and tmdenames of Microchip Technology, Inc. , Parallax is the tradename of Parallax, Inc.]

CIRCLE 163 ON FREE INFORMATION CARD

www.americanradiohistory.comAmericanRadioHistory.Com Low Cost CAD Software for the IBM PC and Compatibles SHOW TIME CABLE Now In WindowsTM Your Cable *II Design & Connection Simulation To The Stars!

rIllItart111.1 PCB. Order your FREE Layout catalog today! 10 1- 800 -643 -4258 t 1'' Easy to use schematic entry program (SuperCAD) for circuit diagrams, only $149. Includes netlisting, bill of materials, extensive parts libraries, More parts, and automatic wiring available in enhanced CAD package (SuperCAD+) for only $249. Powerful, event -driven digital simulator (SuperSIM) allows you to check logic circuitry quickly before actually wiring it up. Works cirectly within the SuperCAD editor from a pulldown menu and displays results in logic analyzer" display window. Starting at $149 this is the lowest cost simulator on the market. Support for PALs, a larger library, and a separate interactive logic 1 viewer are available in full- featured SuperSlM+ for only $399. Library parts STARGATE SST include TTL, CMOS and ECL devices. Circuit board artwork editor and autorouter programs (SuperPCB), starting at Converters & Descramblers $149. Produce high quality artwork directly on dot matrix or laser printers. You can do boards up to 16 layers including surface mount. Includes Gerber and All Makes & Models Excellon file output. Autorouter accepts netlists and placement data directly Discounts from the SuperCAD schematic editor. Quantity Low cost combination packages with schematics and PCB design: 2 -layer for 30 -day Money Back Guarantee $399, 16-layer for $649. Best Warranties DOS version available. Write or call for free demo disks: \\ Show Time Cable MENTAL AUTOMATION, 643 N 98th St STE 260 5415 - 136th Place S.E. * Omaha, NE 68114 Bellevue, WA 98006 (206) 641 -2141 COD MasterCard Visa Amex Discover BBS (206) 641 -2846

Think you have all the tools ?..., What about the ELECTRONIC DATA BOOK

FINDER MDS is a New Electronic Components Data Base software especially designed for Engineers, Repair companies, Students and Hobbyists.

32,000 components with their data sheets,283,000 IC's substitutions,more than 9,000 pages of information,15 families of components, Thousands of equivalences for Transistors, Diodes and MosFets,more than 500 package designs,12 Mb of Technical information.

FEATURES Searching for components by Name, Function or Characteristics - Customizable search forms - User friendly Interface - Graphic and Text Editors included - Ultra fast search - Information can be add to any component - Technical forms similar to Manufacturer's Data Books - Printout facilities - Technical forms can be exported to any word processing software Custom data base to add your own components. FINDER MDS runs on IBM PC /AT or compatible with 1 Mo RAM, HD, EGANGA display, DOS 3.1 min.

FINDER MDS 5.0 - Now only $ 149.95 (S &H charges not included) To order call : 1 (800) 279 0393 Electronics Software Solutions 3025 N. Ocean Blvd - Fort Lauderdale - FL 33308 - Tel (305) 561 4340 - Fax (305) 561 4418 121

www.americanradiohistory.comAmericanRadioHistory.Com Enter A World Of Excitement with a Subscription to Popular Electronics

Get the latest electronic technology and information monthly! AUTOMOTIVE ELECTRONICS FOR THE 21ST CENTURY Now you can subscribe to the magazine that plugs you into the exciting world of electronics. With every issue of Popular Elec- tronics you'll find a wide variety of electronics projects to build and enjoy, and feature articles that inform and entertain. Build a Radar Popular Electronics brings you feature articles on technology, computers, test gear, and more -all designed to keep you tuned into the latest developments in electronics. So if you love to build ¡pod S-1111---- fascinating projects , just fill out the subscription form below to It works just ' t Simple PC subscribe to Popular Electronics... It's a power -house of fun for like the ones used r. (- -Upgrades the electronics enthusiast. by the police " You Can Do EXCITING MONTHLY FEATURES LIKE: Adding hard- and Build the tloppydisk drives CONSTRUCTION -Exciting projects that range from simple Sun Tracked Get the most out radios to working robots of solar-power gea FEATURES -Learn about new technology, see how to troubleshoot all types of electronics gear, refresh your knowl- Builfan

edge of basic electronics theory, see how components work nvel IP A and how to use them in your own designs, and much more J l' J PRODUCT REVIEWS -Get in depth, hands -on reviews of all 11í14%U! types of hobby gear, and learn about the latest and the great- est in consumer electronics in our no- holds- barred Gizmo

section Computer Bits, Ham Radio, Scanner Scene, SPECIAL COLUMNS -Think Tank, Circuit Circus, Comput- Circuit Circus, and More! er Bits, DX Listening, Antique Radio, Scanner Scene, Amateur Radio, Multimedia Watch, and more FOR FASTER SERVICE CALL TODAY PLUS: ALL OUR GREAT DEPARTMENTS! You'll get 12 exciting and informative issues of Popular Electron- ics for only $18.95. That's a savings of $23.05 off the regular sin- 1- 800 -827 -0383 gle copy price. Subscribe to Popular Electronics today! Just fill out (7:30AM- 8:30PM) EASTERN STANDARD TIME the subscription order form below. APEG5

Popular Electronics SUBSCRIPTION ORDER FORM P.O. Box 338, Mt. Morris IL. 61054 YES! I want to subscribe to Popular Electronics for PLEASE PRINT BELOW: 1 Full year (12 Issues) for only $18.95. That's a savings of $23.05 off the newstand price. (Basic Subscription Rate -1 yr /$21.95) NAME Payment Enclosed Bill me later Please charge my: [J Visa Mastercard ADDRESS

Acct #I111I 111111111 CITY STATE ZIP Allow 6 to 8 weeks for delivery of first issue. U.S. Funds only. In Canada add $6.68 Postage (Includes G.S.T.). 122 Signature Exp. Date All Other Foreign add $7.50 Postage.

www.americanradiohistory.comAmericanRadioHistory.Com ''..1.1 V .:.1

We understand the needs ottodays service professional. Wide selection, fast delivery and competitive prices are vital to the survival of your (Atrajo business. For over 15 years MCM has provided all three. Our 324 page 200C catalog is packed with over 21.000 items including Test Equipment, Semiconductors. Chemicals. Tools. Computer Products, TVNCR Parts and much more. Deep inventories enable not only competitive pricing, but rapid delivery. Over 99 of all orders are shipped within 24 hours. One call puts all of this at your fingertips. Call today for your tree catalog and you'll discover... MCM is your #1 source.

Product questions ...1- 800 -824- TECH(8324)

MCM ELECTRONICS ' 650 CONGRESS PARK OR Hours: M -F 7a.m.- 9p.m., CENTERVILLE. OH 45459 -4072 Sat. 9a.m.- 6p.m. EST A PREMIER Company GET FAST DELIVERY FROM OUR DISTRIßN CENTERTON, OH AND RENO, NV! POP -20

CIRCLE 160 ON FREE INFORMATION CARD PROTOTYPE PC BOARDS! co NTURELAYS LIGHTS MOTORS only MTEMPERATURE EASeJ PRESSURE LIGHT LEVELS HUMIDITY RE $595! free CAD'CAM SWITCH POSmONSN PVTTHERMOSTATS LIQUID LEVELS

PLUGS INTO PC BUS RS -232 INTERFACE 24 LINES DIGITAL I/O 8 DIGITAL I/O 8 CHANNEL. 8 ANALOG INPUTS 8 BIT A /0/ IN 2 ANALOG OUTPUTS 1I BIT COUNTER 2 COUNTERS.24 BIT 18"x18 "x4.6" WORK AREA UP TO 14K SMP/SEC

THIS IS THE MACHINE YOU'VE BEEN WAITING FOR! 12 BIT 100 KNZ A/U RS-23I INTERFACE Have you ever dreamed of letting your computer prototype PC boards directly from 4 ANALOG OUTPUTS TRMS, 20 AMPS your CAD drawings', If so, the Neuractor CNC -4+ Desktop Manufacturing System may 3 TIMER COUNTERS 1281T A/D i$iy. be Just the machine you need! This fourth -generation CNC machining center can a 2109 24 DIGITAL I/O OPTO ISOIATED automatically drill, mill and route printed arurt boards, not to mention three - COMPLETE OMM dimensional products in wood, plastic and light metals DIRECTLY FROM YOUR CAD DRAWINGS! You've seen the rapid- prototyping and "Santa Claus" machines that cost thousands of dollars, but did you know that as an electronic technician you can MODEL ., 4e , M- ::g9,. assemble one yourself from this inexpensive kit, Utilizing patent pending technology the Neuractor CNC -4+ kit provides you with everything you need to machine products RS.232 INTERFACE RS-232 INTERFACE in with 28 LINES DIGITAL I/0 18 BIT A/O three dimensions a resolution of 001" All mechanical components are pre- 8 ANALOG INPUTS 5.5 DIGIT fabricated, pre-machined, plated and painted. Includes four 83 oz /in digital CY- PWM OUTPUT UP TO 60 SMP/SEC MOTORs, interface card, 5 amp power supply, 10 pitch steel lead screws, 4 proprietary Slide Block actuator mechanisms, 4 aluminum linear actuator channels, polished steel

guide -rods, Dremel bracket, hardware, etc (You provide Dremel MotoTool(tm) or flex -

shaft router and work surface ) It's a complete Kit! All you do is put it together and calibrate Al IF THAIS NOT ENOUGH, WE'RE THROWING IN A FREE FULL -FEATURED 3D CAD /CAM SOFTWARE PACKAGE WITH EACH UNIT! Large 18'xlB x4.6 "cutter travel Prairie Digital, Inc. directly from CAD -generated or scanned ASCII, DXF 8 HPGL plot files I. Get started by ordering your own Neuractor CNC -4+ today ACT NOW! Krt $595 + $24 95 S/H PHONE 608- 643 -8599 FAX 608 -643 -6754 For PC board routing the heavy -duty upgrade is suggested, add $149) Allow 4 -8 weeks 846 SEVENTEENTH STREET PRAIRIE DU SAC, WISCONSIN 53578 for del. U S. CYBERLAB, 14786 Slate Gap Rd West Fork, AR 72774 (501) 839 -8293 Free info! X -Y Power /Rotary Tables and larger CNCs now available! 123 Enter No 47 on Reader Service Card

www.americanradiohistory.comAmericanRadioHistory.Com FREE TM catalog and construction plans for any of these kits (limit two) WeederTechnologies Call 513- 752 -0279 Pro' it P.O. Box 421, Batavia, OH 45103 Educational Kits for the Serious Hobbyist

Caller Block Telephone Caller ID Telephone Call Restrictor 50 MHz Frequency Counter

Connects between your telephone Connects to telephone wall jack. Connects to telephone wall jack. Disables Reads frequency from 1 Hz to 50MHz and and its wall jack, and prevents the Shows the telephone number of all phones on the line if attempting to displays it on a 16x1 character LCD phone from ringing unless the the calling party along with the either: dial a number that has been stored display. Auto-range feature provides calling party Is one which you've time of day the call was received, in memory 'Block Mode' or, dial a number floating decimal point and automatically entered Into memory using your one 16x1 character LCD display. that has not been stored in memory 'Allow affixes the correct suffix (Hz, KHz, or MHz). touch -tone phone. Your answering Stores the info from the last five Mode'. Use touch -tone phone to enter Microcontroller based, very few additional machine can handle all other calls. calls in memory. Complete stand telephone numbers into memory, and components. $46.50 Change between two separate alone, no computer interface choose mode. Program from any phone directories of callers with a simple needed. $52.50 on the line using your password. $35.00 flip of a switch. $48.00 DTMF Decoder /Logger Vocal Filter Telephone Scrambler Electronic Message Module Keep track of all numbers dialed An audio device which can be from any telephone on your line. Scrambles your voice before Use a set of four pushbutton switches to used with a home component Connects to your telephone wall sending H over the telephone write and store your own personal message stereo system, to filter out the jack. Decodes all 16 touch -tones line, and descrambles it on the in a B -pin non -volatile EEPROM, which can main vocal sound track from and displays them on a LCD other end. Connects between then be printed across a 16x1 LCD display. standard stereo recordings (CD, display. Holds the last 240 digits in your telephone and wall Jack. No Message can be up to 240 characters long. tape, record or FM), leaving the a nonvolitile memory. Use the 'shift modifications are required to EEPROM can be removed from socket and background music to sing along back' and 'shift forward' buttons to your telephone. Full duplex still retain message. Re- program over and with. Produce your own karaoke scroll through and view all numbers operation. $43.00 over with new messages. $44.50 tapes. $40.00 in memory. $54.50

able Test Orders only A Information PE MARKET CENTER CLASSIFIEDS -8004311-7090- !11 s (310)902 -0841 Test chips for JERROLD, 71COM ZEMTIL SA. & Pots cable boxes in full servia moda Easy inrt- adon. Zenith only $39.95. Most others under $50ra. MISCELLANEOUS CABLE TV FAX- (3 l)05102 - 063 I Qs+aötY Frias available.a 1YV Ck .A: ltbr for tae in tableen owned equip For am .!.r aid only ELECTRONICS FOR SALE "BULLET" BUSTER. Protect your cable box against the infamous cable "bullet." The "Bullet" THE CASE Against Patents. Thoroughly tested Buster acts as an electronic shield. Installs in -line and proven alternatives that work in the real world. in seconds. Don't wait until it's too late! $19.95 $28.50. PRESS, Box 809 -C, SYNERGETICS +$3.00 S &H. Visa /MC. ELECTROMAN, Box Thatcher, AZ 85552. (520) 428-4073. Visa/MC. 24474, New Orleans, LA 70184. (504) 482 -3017. IMPROVE TURBO CHARGE your amplifier. Guide to in- CABLE SAFE. Guarantee cable privacy. The wattage of existing power amplifiers. Send - crease one way valve for your cable TV signal. Cable $7.50 for complete book. JAM Electronics, 7391 signals come in, but they don't go out! $29.95, + YOUR St. Hwy 78, Gratiot, WI 53541. $3.00 S &H. Visa /MC. ELECTROMAN, Box CAN TEST CHIPS for testing converter boxes in 24474, New Orleans, LA 70184. (504) 482 -3017. full service mode. Jerrold, Tocom, Scientific Atlan- 1111tA1501 DESCRAMBLER SCHEMATICS REVEALED. A ta, Zenith, Pioneer. Descramblers clears E2 -E5 powerful guide to descrambling schemes. $10.00. Masters, 1 (800) 360-76M PST. WITH OUR Micro Visa /MC. ELECTROMAN, Box 24474, New REMOTE CONTROL miniature encoded trans- Orleans, LA 70184. (504) 482 -3017. A mitters receivers. Send for free catalog to: and CABLE UNSCRAMBLED. Everything you want Inventive Solutions, PO Box 8, Stratford, NY to know about cable, but are afraid to ask. $10.00. 13470. Visa /MC. ELECTROMAN, Box 24474, New TESLA COIL parts, enameled wire, secondary Orleans, LA 70184. (504) 482 -3017. coils, more. Catalog $1.00. K &D Electric, PO Box UNIVERSAL DESCRAMBLER. Unscramble sig- 659, Newcastle, OK 73065. nals using your VCR as the tuner. Works with virtually any system, this is the only one you need. Declare cable box independence! $129.95 + Quality Microwave TV Antennas $5.00 S &H. Visa /MC. ELECTROMAN, Box 24474, New Orleans, LA 70184. (504) 482 -3017. WIRELESS CABLE - IFTS - MMDS - Amateur TV Ultra Hipp Gain 5816(+) Tuneable 1.9 to 2.7 GM. ATTN. CABLE box owners. Get your Bullet and ID 55- Channel Dish System $199.95 stopper before it's too late. Send $20.50 to R.A. The clearest picture possible Channel Dish System $149.95 36- Enterprise, Box 3532, Easton, PA 18043. movies. 20- Channel Dish System $124.95 playing back Optional Commercial Grb Antenna (not slaws) Add 550.00 Vagi Antennas, Components, Custom Tuning Available CABLE DESCRAMBLING, New secret manual. GUARANTE Call or este (SASE) for "FREE" Catalog Build your own descramblers for cable and to eliminate copy protection. MIIIIIPS -TECH BFCTNOMCS subscription TV. Instructions, schematics for Dos Byatem P.D. Box 8533 Scottsdale, AZ 85252 SSAVI, gated sync, sinewave, some free No Rolls/Jitters/Flickers /Fading all phone order's) UFETIME 1502) 947-7700 153.00 Credit methods (HBO, Cinemax, Showtime, UHF, aer Express COO's Quantity PA Works on all TV's, VCR's Beta & Cable WARRANTY aadUCard Yon Ñ, Adult) $12.95, $2.00 postage. CABLETRONICS, Gold Video Connectors & Cables Included Box 30502PE, Bethesda, MD 20824. 2 Year Warranty OWN YOUR cable box or ZAP IT! Quality prod- Money Back SECURITY ucts. Money back guarantee. 1 -year warranty. Toll Guarantee _ The for less, 1 HI -TECH. ELECTRONICS, best free: (800) 899 -9707. (spy, security, laser), catalog $5.00 postage: F & P Enterprises, Box 51272, Palo Alto, CA 94303 -A. VISION MISCELLANEOUS ELECTRONICS ELECTRONICS WANTED EDUCATION TEST EQUIPMENT WANTED. I will buy your late model test equipment, electronic components, 1-500-562-2252 LEARN IBM PC ASSEMBLY LANGUAGE. Disk commercial and military connectors. Small quan- $5.00, Book $18.00. ZIPFAST, Box 12238, tities or entire inventories. Bob Morgan, Test 124 2125 S. 156TH CIRCLE OMAHA. NE 68130 Lexington, KY 40581 -2238. Equipment Sales, Ph /Fx (717) 842 -1534.

www.americanradiohistory.comAmericanRadioHistory.Com Learn MICROCONTROLLERS Tap into a World of... EMBEDDED SYSTEMS and FREE ELECTRICITY PROGRAMMING with Our 150+ page Self-Reliance Catalog IS JUST LOADED WITH DC to AC the New AES -10 ENERGY INDEPENDENCE ... The AES-10 .. a complete '' kV 1:5í''' V We offer: learning system, a complete Solar, Wind & Hydroelectric embedded control system v Extensive manuals guide you 'AN . energy systems. True Sine through your 8051 development project. ya?*« Wave DC to AC Inverters. Assembly, BASIC, and C programmable. trd 40 Electric Boat & Car kits. All hardware details, complete schematics. Learn to program the LCD, keypad, digital and Portable power packs. analog UOs . The entire board is software reconfigurable Solar Lighting & Cooling for your applications. Everything you need, nothing extra required. systems. Solar Pool Heaters. 80C32 Computer /Microcontroller board with: Solar Battery chargers. Solar Books & Toys. DC Appliances. 32K Byte ROM , 32K Byte RAM 2 by 16 Liquid Crystal Active & Passive Solar Air & Display 4 by 5 Keypad Two serial ports 5 interrupt sources 3 timers A/D , D /A, PWM and digital I/O Built in Water Heating Systems. Logic Probe Power supply (can also be battery operated) Composting Toilets. Hydroponic, Extended Intel BASIC and AES Monitor in ROM RS -232 Fish -Farming, Solarium & Green- cable to connect to PC for programming 8051/52 DOS Cross house Systems. Water Testing, Assembler Program disks with well documented examples User's Manual, Language Manual, and Text (over 400 pages). Treatment, & Pumping Systems. Emergency Food & H2O Kits. High Efficiency AC /DC Refrigeration + More... AES -l0 $285 Complete Free Info Pack, M/C Visa FOR ... Money Back Guarantee 714 - 550 -8094 A LOT OF INFORMTION ONLY $5.75 Fax 714 - 550 -9941 SEND CHECK or MO TO: Self- Reliance Company Inc. CALL 1 - 800 - 730 -3232 AEA P.O. Box 306, Florisssant, MO 63032

970 W. I 7th St.. Santa Ana, California, 92706 USA

Cellular Programming Software $$ SLOW COI PRICES Si WE'LL BEAT ALL COMPETITORS' ADVERTISED PRICES

MOTOROLA ABOVE 9122 ALLMODELS SOFTWARE OR LOADER FROM $395.00 NOKIA & TECHNOPHONE 100.101.121 - 201 - 400 - 405 - 415 - 515 - TANDY MODELS NEC P100- P110- P120- P180- P400 -P600 - ATT3610

PANASONIC ALL PORTABLES HP600 - HH700 - HH900 - EBH30 - EBH40 - EBH50 - EBH60

GE & ERICSSON HOTLINE - POCKET II - MICROPORTABLE - AH97 - AH98 -CT100 - .CT700 MITSUBISHI & DIAMONDTEL 3500 - 4500 - 20X - 22X SONY CMR -111 -333 MOTOROLA SOFTWARE TO REPAIR LOANER AND 000FFFFF

All PRODUCTS ARE IN STOCK CopyCat® No PC - No Loaner SHIPPED OVERNIGHT UPS /COD Only 10 Seconds Programs & Repairs Complete with Cables * * * All Motorola Including Digital - Analog - All Versions L.1 :...,$ .. * * * OFT Available from $2300.00 Models I * ** 609-751-2242 Ext 2 Sony - Erlceeon - Panasonic Audlovox - NEC - Mitsubishi FAX 609 -751 -5549 FREE TECHNICAL SUPPORT Dlmontel - GE - Uniden 125

www.americanradiohistory.comAmericanRadioHistory.Com CABLE TV DESCRAMBLER KITS Universal-New Product Tri -Mode Descrambler SB -3 Descrambler This Product includes all the Parts, This product includes all the parts This Product includes all PC Board, Complete Schematic PC Board and AC Adaptor. the Parts, PC Board and with Functional Guide. Generates NO Enclosure included. AC Adaptor. Enclosure Sync for most Video Applications. is not included. $79.95 S59.95 $44.95 Call Toll Free 1- 800 -886 -8699 M & G Electronics, P.O. Box 3310, No. Attleboro Mass. 02761 VISA

Anyone implying theft of Cable service will be denied assistance. NO MASSACHUSETTS SALES!

PE MARKET CENTER CLASSIFIEDS

PLANS -KITS -SCHEMATICS YOU WON'T be caught flashing with SILENT CABLE TV EQUIPMENT SAM. Patented vehicle turn signal reminder warns We carry a complete line of all major brands BUILD FIVE- digit, ohms, capacitance, fre- when not to. See PE's Apr. '95 Hands -On Report. Including test chips and all accessories - quency, pulse, multimeter. Board and instructions Call toll free 1 (800) 398 -5605 Visa/MC. Kit w /case BELOW WHOLESALE PRICES QUANTITY DISCOUNTS $9.95. Bagnall Electronics, 179 May, Fairfield, CT $15.00, $22/$27.00 wired models, plus $2.50 30 DAY MONEYBACK GUAR. 1 YR. WARRANTY 06430. P &H. Flyer. 1627 Basil Dr., Columbus, OH 43227. YEARS OF CUSTOMER SATISFACTION C & C ELECTRONICS ALL-IN -ONE catalog. AM /FM /ham /spy, trans- NIGHT VISION kits! Build a night vision scope mitters, amplifiers, receivers. Voice scramblers/ with our easy to assemble, complete kits. Save $! CALL NOW 1- 800 -995 -1749 disguisers, audio, TV, Tesla Immed. Delivery from Giant Stock' Sorry no Florida Sales. coils, plans, "secret" Our best scopes are capable of 0.0005 lux! U.S. books, kits, imports, exports and more. Start your made image intensifiers, I.R. tubes, etc. Great for own licensed or unlicensed radio station, 60 full astronomy, science projects or any nocturnal ac- pages for $1.00. PAN -COM INTERNATIONAL, tivity. We also sell a complete line of brand name PO Box 130 -H7, Paradise, CA 95967. U.S. and foreign units to suit any need. North East Night Vision Supply, PO Box 1088, 320 Main FM STEREO TRANSMITTER kit broadcasts any MA Ph /Fax (508) Prototype audio signal to FM stereo radios Street, Sturbridge, 01566. it FAST! throughout your 347 -7238. with ßuloaaica IOS1 or a home. Uses unique BA1404 IC. Completelcit: PC I!` C010 squ camm top &VI board /components $24.00. Visa /MC. ra .,or+0+ve,... - o mewl L. oa : R .w TENTRONIX, 3605 Broken Arrow, Coeur d'Alene, ö ..P,-P,.. ID 83814. (208) 664 -2312. SATELLITE EQUIPMENT uDOSmüsnm e., ProloOuld HOBBYIST CIRCUITS n aM 10.51 - Remote room monitor, SATELLITE RADIO BOOK AND GUIDE. New tone decoder, long distance circuit control and book covers all audio services, SCPC, subcar- $99.00 more. Simple .. experiments for the beginner. CAT- riers, FM squared, facsimile, press services, ALOG $2.00 Garrett Plans, Box 155, R n - weather p.0w4,0. 11pnCAM1One o, pe,,., a,,,n. services. Simple how-to- receive instruc- 561.2060 Jamesburg, NJ 08831. M. IMfenal pon WRNOUT PROGRAMMING ® (513) tions. $16.95 plus $3.00 Priority Mail. UNIVER- SURVEILLANCE TRANSMITTER klts. 65 to 305 SAL ELECTRONICS, 4555 Groves Road, #12, MHz. Quick & Easy. Partially assembled units. Columbus, OH 43232. (614) 866-4605. Five minutes completion. 110 -volt duplex recepta- VIDEOCYPHER II descrambling manual. room Sche- cle, battery types, and telephone. Counter - matics, video and Explains surveillance. audio. DES, EPROM, Catalog: $2.00. SHEFFIELD ELEC- CloneMaster, Pay-per -view (HBO, Cinemax, TRONICS, PO Box 377940 -B, Chicago, IL Showtime, Adult, etc.) $16.95, $2.00 postage. !!! BROADCAST FARTHER !!! 60637 -7940. The model 1525 is a 75- 110MHz RF amplifier the connects to mono or Schematics for Videocypher Plus, $20.00. Sche- stereo FM transmitters and produces a powerful 15 -20 watt signal which CRYSTAL SET Handbook - Visit antiquity by matics for Videocypher 032, $15.00. Collection of could broadcast up to 5 miles or more! Requires 75 -250 mW drive. building the radios your grandfather built. Assem- software to copy and alter EPROM codes, $25.00. Step by step plans complete with part source PLUSUS $2 S &H ble a "Quaker Oats" rig, wind coils that work and VCII Plus EPROM, binary and source code, information and antenna designs ... ONLY 14 c.o.o.. make it look like the 1920's! Only $10.95 plus $30.00. CABLETRONICS, Box 30502PE, Progressive Concepts Bethesda, MD 20824. C 1434 N. MILLS AVE.. SUITE A $4.00 for shipping and handling. CLAGGK Inc., CLAREMONT, CA 91711 (909) 626 -4969 (909( 626.4© PO Box 4099, Farmingdale, NY 11735. US funds LOWEST PRICES. Shop around, call us last. only! USA and no Canada - foreign orders. Free price list. 43 years in business. ANTENNA SCHEMATICS, PARTS, equipment - can't find? KING, 6502 6th Ave., Bayridge, NY 11220.1 (800 Arnold Enterprises, 1218 Dandridge Drive, 814-5377. International (718) 745-8200. Fax (718) SOUP EWE ILLANCE Lynchburg, VA 24501. 921 -3900. & COUNTERSURVEILLANCE Electronic Devices CIRCUITS! CIRCUITS! The very best in plans, Hidden Video Cameras Electronic Kits Voice Changers kits, schematics, and books. Too many to list. Bug and Phone Tap Detectors Shotgun Mies Micro Recorders Satisfaction guaranteed! Send for free listing. Vehicle Tracking Locksmithing AND MORE! HOBBYTECH, Dept. PE1, 1748 SE Alder, AUDIO -VIDEO -LASERS Hillsboro, Extra Long Play Telephone Recorders - Silently Tapes $12500 OR 97123. LASERS, LIGHTSHOWS, Holography. Lowest lncoming/Outgoing Phone calls automatically.. and Up UNBELIEVABLE! MICRO 1.5V FM transmitter prices. For free catalog write: Midwest Laser Prod- SDY FOR CATALOG SEND $5.00 TO...P.O. Box 337, kit. Reg.$39.95, now $12.00! HURRY! RJJ, Box ucts, PO Box 2187, Bridgeview, IL 60455. Or call: OUTLET Buffalo, NY 14226 (716) 691 -3476 - (716) 695 126 -8660 6555 Stn. D. London, Ontario N5W 5S5 Canada. (708) 460 -9595.

www.americanradiohistory.comAmericanRadioHistory.Com DC /CAD introducing... THE TERMINATOR CABLE T.V. EQUIPMENT Super High Density Router (Complete with Schematic & PCB EDITOR) Friendly, Knowledgeable Service

Features the following powerful algorithm & capability:

Rip - up and Retry Pre- routing of SMT components C all tocpC, Real-Time via minimization CIC price Real-Time clean up passes pomr;t\ 5pc gZy- ORDERS CALL: User defined strategies $Z 1 -800 -361 -4586 Window 3.0 capability as DOS Task

1 -mil Autoplacer and Autopanning Two-way Gerber and DXF Automatic Ground Plane w/ Cross -Hatching 011111111 Complete w/ Schematic & Dolly Libraries All Equipment New Optional simulation capability & protected mode for 386 users Convertors & Descramblers *PCB LAYOUT SERVICE AT LOW COST * 30 Day Money Back Guarentee 6 Month Warranty LEASE PROGRAM & SITE LICENSE AVAILABLE q%MI Visa, MC, C.O.D. Welcome % i VDE ELECTRONICS, INC. , 17 kadrr P.O. B DX 1494 Design Addison. IL 60101 Computation Info. 708-889 -0281 1771 State Higaway 34 Farmingdale NJ (77"7"27 Fax 708-889-0283 (9081 681 - 770(T (9Ò8g 681 - 8733' (FAXT " DC /CAD ... The focal point cffrisure CAD market

Electronics made Easy with UCANDO

UCANDO's unique computer animation makes learning electronics fast '+'/./ff..%% ry , '+ easy. These videos will...allow you to learn at your own pace...help :i't "': -er jf and f y.''..'.,. you remember more of what you learn ... give you years of quality use... become a valuable source of reference material...make your understanding of electronics complete ... and help you build your future today. Call today and see how UCANDO is... "Changing The Wati' The World Learns Electronics."

New Release!!! VT405 TV Part 2 "The Front End" $44.95

VT102 Introduction to VCR Repair ... $44.95 VT206 Oscillators . $44.95 VT401 AM Radio $44.95 VT103 VCR Maintenance & Repair .. $29.95 VT301 Digital 1 $44.95 VT402 FM Radio Part 1 $44.95 VT201 Direct Current $44.95 VT302 Digital 2 $44.95 VT403 FM Radio Part 2 $44 95 VT202 Alternating Current $44.95 VT303 Digital 3 $44.95 VT404 TV Part 1 "Intro to TV" $44.95 VT203 Semiconductors $44.95 VT304 Digital 4 $44.95 VT501 Fiber Optics $44.95 VT204 Power Supplies $44.95 VT305 Digital 5 $44.95 VT205 Amplifiers $44.95 VT306 Digital 6 $44.95 SAVE!!! Buy any 6 videos for only $240 ... SAVE MORE!!! Buy any 12 videos for only $450 MONEY BACK GUARANTEE! Call for details Call toll -free 1- 800 -678 -6113 VI SA l or mail check or money order to UCANDO Videos, P.O. Box 928, Greenville, OH 45331 MasterCard \-)C.-1, FREE Shipping ... FREE Catalog CIRCLE 136 ON FREE INFORMATION CARD

www.americanradiohistory.comAmericanRadioHistory.Com BLACK FEATHER ELECTRONICS

3 1/2 Digit LCD Panel Meter Stepper Motor Controller Kit Camcorder Video Tape

features: 200mV full scale input 9VDC opera- Ibis kit allows you to adjust the speed and direction HI-8 120 MINUTE TAPE (used) tion. Decimal point selectable. 13mm digit of a stepper mots. You can move the motor in one height, auto polarity indication, zero reading They were recorded on once and played only a step increments or rotate it at a constant speed. few times. Made by a major brand name manu- for 0 volt input. Measures 2.67' o 1.73" o Visual indicator. show the sequence of motion. 0.28" above panel thickness, 0.51" overall facturer. Professional series metal tapes. Includes stepper motor, pc board, parts and instruc- Includes plastic jewel box. thickness. LCD size: 1.83" x 0.8 ": Has many hons.112vdc power source not included.) useful applications and is easy to install. CAT# CCT-1 $3.00 each One match can burn CAT# PM -1 $17.00 each (AT #SMK.I $25.00 each 10 or more - 2.80 each 3,000,000 trees.

1.800.526.3717 1. California residents must include sales tax. Black Feather 2. Checks and money order accepted. 645 Temple it A long Beach A California 90814 A Publie r ELECTRONICS Setier of Th Map ,ne & The AIM/17, Cpl., A (310) 434.5641 A FAX (310) 434-9142 a 3. Ouanties li -iteri - prices subject to change. t7"

NEW!!! New Jerrold eeAe AMERO h.. "Descrambler "! RE/ VP

Only $69.95! we« FTEI-0os Video RE L-00] ANDNEllVl (plus $8 S &H) Learn how to repair today's electronic 30 Day Warranty! communication equipment and SAVE big SUC by repairing it yourself!!! NN'T EASY. Electronic equipment seem to always Wireless command the break down just when the warranty Especially for one person expires. By using these training videos, Jerrold box you rent to you can do most repairs quickly like yourself who's trying to do without descramble ALL channels! added expense. the work of three. So why not These well -illustrated videos show So small, it fits in the you how communication devices hire one or two of the thou- operates, from its features down to palm of your hand! component level. sands of young disadvantaged Works on DP5,DPV5, DP7, people looking for work this DPV7, DPBB, CFT models. Previously released Video summer. Hiring them can also TEL -001 also available help you get as much as an Jerrold & SA 8600 test TE LE PHONE THEORY 85% tax credit on the first chips also available. REPAIR $3,000 in wages you pay to one of these summer employees. Order Toll Free 24 hrs For further information, write Video /TEL -0a1 1 -800- 417 -6689 the National Alliance of Business P.O. VISA /MC /DISC, MO & COD Order today!!' at Box 7207, Washington, D.C. 20044. And Video #TEL -001 - Do not use these devices without authorization Video #TEL -002 support your local summer from your local cable company. Video #TEL -003 jobs- for -youth programs. No GA & TN sales. for only $33.95 each Make living in the summer- (Includes $4.00 S &H cost) time easy. Illinois Residents add (7 %) state and/or sales tax LET'S GET ALL OF AMERICA WORKING AGAIN.

Satisfaction Guaranteed - OYMB giA PUBLIC SERVICE Satellite -TV OF THIS PUBLICATION & THE ADVERTISING COUNCIL. SAVE 40% - 60% Send Check or Money Order to: ,.6,40;/ 800. 334.6455 218-739-5231 Intl PCW Technical Productions 218- 739.4879 Fax P.O. Box 1492 Skyvision Inc.' Arlington Heights, IL 1 . FRONTIER DRNE FERGUS FALLS MN 60006-1492

www.americanradiohistory.comAmericanRadioHistory.Com FROFESSIONAL SURVEILLANCE EQUIPMENT Used By Law Enforcement Agencies Free ' Parts VHF -FM CRYSTAL CONTROLLED TRANSMITTERS 149.450 Catalog! A - 139MHz, B - 139.970 MHz, C -149 MHz, D - MHz All kits assemble in less than 5 mins. Fxpress' AD- Featuring the F300 Gargeo Best New us brass plant Products from Parts with 6 Express is mirrors and Major sa Many proud to concealed BOW video AD -700 iAD -80 AD -550 AD-400 Manufacturers announce that camera and video Mic Mic Tel, Mic we now stock the transmitter. Great for Range: Range: Range: Range: v Hand Tools monitoring in living upto5 up to 1.8 up to .5 upto2.5 NTE line of replace- roam, conf. room, Mile Mile Mile Mile v Tool Kits & Cases office, or anywhere. Power Power Power Power ment semiconductors. Range 150 ft. 3880 750MW 80MW 35MW 400MW Test Equipment NTE has been 13990 wlaud) $272 $187 $150 3163 supplying the electronics If you need our technology in a diff. configuration for your needs. Soldering Supplies have -the industry with tap riot lh replacement parts call! We can probably build it for you. We other state -of . Wire /Cable /Connectors art surveillance equip. too! for over 15 years. Ail NTE Bench Accessories We sell a variety of cameras, bug detectors, night vision products meet or exceed equipment, video transmitters, time lapse recorders, and Call: 800 -426 -1194 FAX: 800 -366 -9662 industry specifications remote video monitoring systems, and many more... offer an exclusive 2 year A &D ELECTRONICS manufacturer warranty. JENSENTOOLS INC. We also offer a complete P.O. Bou 601, Mousey, Nv 10952 7815 South 461" Street 914- 356 -7541 Fax 914- 356 -7505 line of parts for the service repair Phoenix AZ 85044 -5399 Request our full catalog for 56, get 510 off your first order. industry. Test equipment, loudspeakers, Credit Cards accepted video and audio heads, magnetrons, 4CIRCLE 116 ON FREE INFORMATION CARD belts, idlerassembl es,

r tools, soldering egLip- ment, just to name some of the 12,000 items we stock. Ask about our new EASY PC i dealer program for NEW resellers. Call toll free for a copy of our FREE 212 l _ page catalog. Source en:*,swxao Code: POM SCHEMATIC and PCB C.A.D CALL TOLL FREE ONLY The Pocket Programmer Includes 1- 800 -338 -0531 The portable Eprom programmer that Parts Express 340 E Fest .31, Dayton, Ohio 45402 -1257 MGA, CGA, EGA Pone: 5 -3-222 -0173 Fax. 513- 222 -4644 & VGA compatible. uses the printer port of your PC instead CIRCLE 148 ON FREE INFORMATION CARD an internal card. The software has 24 Design luge multi layer of boarda. easy to use functions and programs

One level pull down 27/25/28/68764 & Cmos from I6K menu and quick keys (2K x 8)-2M (256K x 8) Eproms for fast layout. (32 pin socket, UpGradeable to CABLE TV HIO Dot matrix, hater, planer, UTOMATION 8Meg). Adapters available for MCU's, Gerber & N.C. drill output. 4111111"Mi DESCRAMBLERS 40 -Pin Eproms, 5 -Gang and Eprom 6 Mouth Free x -te 7840 ANGEL RIDGE ROAD Emulator to 32K 8. Free Demo ATHENS, OHIO 45701 INTRONICS, INC. $129e95Vr (614) 592-1810 Box 13723 Add $4.00 for shipping. Visa 8 MasterCard Accepted -_ Edwardsville, KS 66113 Add $4.50 for COD. (913) 422 -2094 Visa /Master Charge

We have Descramblers for: PROGRAMMERS Jerrold-`'' Systems EOUIPME 1349 DATA 110 CHIPLABS 4800 Scientific Atlanta ' r Dinot 799 DATA I/O CHIPLABS 3200 nationwide source Systems 579 EETOOLS ALLMAX for cable TV equipment SUPERPRO (R) 249 XELTEK *BUY WHERE THE DEALERS BUY.' . To --on' Systems 599 LOGICAL DEVICES 3000 599 ADVANTECH PC -UPROG TV Cable Deecremblers . Zenith1l Systems and Convertsrters Catalog. 269 SUNSHINE UNIVERSAL Open Every Osyl . 449 TUP -300 HILO SYSTEMS 111111 Pioneers Systems , MCT-EMUP YOUR VCR TAPES 1 I 449 JDR strsekrlp GUARANTEED TO WORK 539 TUP-400 HILO CAN PLAYAS OR YOUR MONEY BACK! -20 429 NEEDHAMS EMP CLEAR AS DAY! BEST DRICEE FREE CATALOG 679 NEEDHAMS SA -20 UNJAM NOW WITH Please have the MAKE & MODEL # of your 139 EETOOLS 1 GANG area's caole b.» reedy when you cal! 199 EETOOLS 4 GANG Video Decoder 49 SUNSHINE 1 GANG Easy Connections ALLSTAR ELECTRONICS 99 SUNSHINE 4 GANG ,,,f Elimktetee lemming' ! JlrD Cogy env tape 2 veer Wwrerey 169 SUNSHINE 8 GANG 800 -782 -7214 RC Pkge Included 30 Day Money Bad Gurarese 349 SUNSHINE 16 GANG HOURS: 9 -6 M-F 10 -3 Sa: EST TV AIE6A EI(OTROAICS , Is rot the talent o Adstar Electronics to defraud any pay VISA 129 GENERAL DEVICE INSTRUMENTS sire operetor. Poyone írrplying haft of service will be denied C.O.D. 1 -800- 676 -6342 Nor. assistance. fill brand lam -used rsteredceonlyerks of they (408) 241 -7376 Fax 2414375 BBS 983 -1234 ecprchve o mers :ne aroused for reference only. 21 S. Main St., Winter Garden, FL 347117

www.americanradiohistory.comAmericanRadioHistory.Com Moton1ess: It started in America! Motion! The creators are the masters in manufacturing the finest video products...

You probably don't associate VCR's with Amer- ican technology. Fact is, video recording has its origins in America and it was 3M that brought video recording out of the lab and into your liv- Create direct linear action with Muscle Wiresa- ing room. Today, 3M video tape is the choice of they actually contract up to 5% when powered! all the major networks. No other tape company Use them in robots, planes, railroads - anywhere has ever won an Oscar or an Emmy. 3M Black you need small, strong all- electric motion. Watch tape follows in this tradition- service and quality go hand in hand. Here are three Black What are Muscle Wires? a" Watch products you should be using at home! For the :Maio Vi'ires are highly processed strands of a clearest nickel -titanium alloy called nitinol. At mom Clean up! With constant playing and using of de- temperature they are easily stretched by up to 5% pictures grading dry or wet cleaners, the output of your of their length. When conducting an electric cur- you ever rent they return to their original -unstretched- video tapes has slowly diminished to an unac- rhape with a force thousands a /times their weight. ceptable level and the VCR plays as if it has a head record! cold! The culprit is most likely clogged and dirty production. This means your Hi 8 format cam- How strong are Muscle Wires? video and/or audio heads. The 3M Black WatchTM corder will produce the best video and audio def- This varies with the wire's size. A single wire can litt from 35 to 930 grans (over 2 lbs)! For more Head Cleaner Videocassette uses a patented mag- inition possible. With the 3M Black WatchTM 8mm ,trength. use several wires in parallel. netic tape -based cleaning formation to remove cassette, the recording capability and performance head clogging debris. No foreign substances such of your camcorder will be significantly enhanced. How fast can Muscle Wires activate? as cloth, plastics or messy liquids and no harsh Priced at $14.95. I ici contract as last as they arc honed - as quickly as 1.1000 of a second. To relax. the wire abrasive materials are present. The cleaner's us- mast cool again. Rates of many cycles per second able life is 400 cleanings or more! 1 are possible with active cooling. rClaggk Inc. - 3M VHS Special Offer P.O. Box 4099, Flexinol Muscle Wire S ecifications It's easy to use. Place the 3M Black WatchTMHead Farmingdale, Wire Diameter (pm) 50 100 150 250 Cleaner Videocassette in the VCR and press the New York 11735 Resistance (S2/m) 510 150 50 20 Play button. A prerecorded message will appear Contract Force (grams) 35 150 330 930 clearly on your screen and an audible tone is heard, Yes, I like your offer and here is my order for Typical Current (mA) 50 180 400 1000 telling you that the cleaning process is now com- 3M Black WatchTM products! How much power do Muscle Wires need? pleted. No guess work; you never over clean! Power varies with wire diameter. length, and Priced at $19.95. 3M Black WatchTM 0900 Hi Band -120 surrounding conditions. Once the wire has fully 8mm Cassette shortened. ($14.95 each) $ power should be reduced to prevent For VCR! overheating. the Once your VCR's record and playback heads are and the cured, unit plays like new, 3M Black WatchTM T120 Hi Pro VHS What are the advantages of Muscle Wires? consider using the finest videocassette you can 4410 Videocassette Small else. light weight, low power. very high buy -the 3M Black WatchTM TI20 Hi Pro VHS ($8.00 each) $ strength -to- weight ratio, precise control. AC or DC 4410 Videocassette. The 4410 is the highest per- activation, long life and direct linear action and much more! forming videocassette available today for use with 3M Black WatchTM Head Cleane' all standard format VHS recording hardware! Videocassette ($19.95 each) $ Get our new 128 page Muscle Wires Here's what you hear and see....A sharp, clear pic- Project Book with full plans for Boris and 14 Shipping and handling per order $4.00 freedom other motorless motion projects, and our ture- brightest ever colors- from streaks, flashes and snow Deluxe Sample Kit with one meter each of -outstanding high -fidelity audio Total Amount in U.S. Funds only$ 50, 100 and 150 pm dia. Muscle Wires - reproduction- optimum camcorder perfor- everything you need to get moving today! mance-maintains recording integrity. 3M Black New York residents add local sales tax. WatchTM video tape is 100% laser inspected to Canadians add $6.00 per order. No foreign 24 -hour Voice Order tone - VISA MasterCard guarantee surface smoothness and drop-out free orders. Do not send cash. performance. Priced at $8.00 800- 314 -5164 Bill my VISA MasterCard To, Request our FREE Muscle Wires Technical Brochure You saw it here first! 3M Black WatchTM 0900 Card No. New 8mm video tape cassette loaded into your Hi Band Book & Expire Date _/_ /_ Deluxe Kit camcorder delivers the finest picture and sound Mondo- tronics Signature only possible in the 8mm format. Extremely fine par- Anselmo Ave. -62 Name (Please print) 524 San #107 $, ticles of pure iron 'alloyed with nickel and cobalt San Anselmo, CA 94960 59.95 deliver a video performance exceeding 400 lines of Address Questions: 415- 455 -9330 Plus horizontal resolution. You get the advantage of an Fax: 415- 455 -9333 $5.00 P &H LCity State ZIP CA orders Internet: mondo @holonet.net add tax exceptional video image with superior audio re- J

International Orders Welcome! First Class P &H: $11.00

www.americanradiohistory.comAmericanRadioHistory.Com Data Acquisition EPROM + & Control Hardware for PC's PROGRAMMING SYSTEM USES PARALLEL PORT ANA100 Analog I/O $ 99 DIG100 Digital 1/0 $ 39 EPROMS (24,28,32 & 40 PIN *) PLUS 27CXXX 1702 *,2708; l 'MS2716 *,32,32A,64,64A,120,128A 8 Channel 8-Bit 8255 PPI 256,512,513,01-1,010,101,1001,1000,1024,210,020 O to 5 Volt input 24 or 48 TTL I/O 2001,220,2048,4001,040,240,4096,25X X,68764/66 14 TTL4 /O lines Lines 28F512, 28F010 Analog output Selectable Base FLASH EPROMS 28F256, 400 Khz sampling Address 28F020, 290257, 290010, 29F0I0 EEPROMS & NVRAMS (18,24 & 28 PIN+CXX) 2210,2212,2804,2816,2916A.29 l 7,2864,286528256 28C010, DS 1220, DS 1225, DS 1230 SERIAL EEPROMS* (8 & 14 PIN PLUS CXX) ADAM Analog/Counter... $ 89 DIG200 Counter I/O $ 79 ERI400, M586572401 ,02,04,08,16,2444,59C:' I 9306, 46, 56, 66, 8572, 82, 92 SYSTEM INCLUDES: 8 Channel 8-Bit 3 16-Bit Counters BIPOLAR PROMS* (16 THROUGH 24 PINS) PROGRAMMING UNIT 0 to 5 van Input 8-Bit input port 74SXXX AND 82SXXX FAMILY PRINTER PORT CABLE 3 18-Bit Counters 8-Bit output port MICROCONTROLLERSI8741, 42, 48, 49, 8751 POWER PACK, MANUAL 400 Khz sampling Selectable Clock C5I,8752,87C52,87C5X XX,87C751 ,87C752,68705 AND SOFTWARE. frequency Input 68HC705, 68HC711 E9, PIC I6C5X, TMS7742 *ADAPTER REQ'D- DIAGRAMS INCLUDED

SOFTWARE - READ,VERIFY,PROGRAM,COPY DISK FILE LOAD /SAVE, CHECKSUM, FULL ANA200 Analog I/O $ 79 ANA201 Analog $129 SCREEN BUFFER EDITOR W/20 COMMANDS 289 READS HEX, S- RECORD AND BINARY FILES 12 ADD $5.00 SHIPPING 1 Channel 12 -Bit 8 Channel -Bit FAST -DEVICES PROGRAM IN UNDER 60 SEC 0 to 5 Volt input x1, x5. x10, x50 $5.00 C.O.D. RUGGED (8 "X7 "X3 ")ENCLOSURE W/HANDLE optional bi -polar Programmable VISA/MASTERCARD MADE IN USA - I YEAR WARRANTY 100 Khz sampling channel gain 24 TTL I/O lines 100 Khz sample ANDROMEDA RESEARCH, P.O. BOX 222, MILFORD, OH 45150 (513) 831 -9708 FAX (513) 831 -7562

Engineering Software - PC /MSDOS

Analyser Ill - Linear Circuit Analysis S 149 AuloSkem - Schematic Drawing program S 29 More Hardware and CompDes - Circuit Design program S 29 Software items available EasyPC - PCB Layout and Circuit Drawing S ?49 Fitted' - Filter Circuit Design and Analysis 5 229 Ask for our current catalog MICRO CAMERA PC -Scope - Digital Storage Oscilloscope for ANA100 ANA150 or ANA201 board 5 39 MasferCardNisa accepted Pulsar - Logic Circuit Analysis 5 149 Sees an entire room through an 1/8" hole

BSOFT Software, Inc. $21 5 introductory price Only 1.65 x 1.65 x .5 inches -491 -0832 * FAX 614 -497 -9971 PHONE 614 90° field of view COLUMBUS, OHIO * 43207 444 COLTON ROAD * operates on 12 volts DC 380 lines of resolution built in electronic iris low light .5 lux standard video output 1- 201 -794 -9766 Northeast Micro ext. 828 Po box 176 Elmwood Park NJ 07407 "What a great collection

fOS AUTOMATE YOUR HOME

of Hundreds of hard- to-find home automation and (noun) wireless control products. Computer control of your home, security systems, surveillance cameras, audio/video control, HVAC, pet care automation and much more. Easy do- it-yourself installation on most products. Affordable, systems start at about $20. The Tax Information Booket has t OOOD . ® -' all the info to fill out your oaaaoeo-` r EIDE) Oat i:-_,_:_ taxes right. Pick one up wherever -n you find tax forms. Largest Selection of X10 Compatible Products in the World Call for our Free 64 page Color Catalog 800-SMART-HOME (800- 762 -7846) Internal HOME AUTOMATION SYSTEMS, INC. Revenue 151 Kalmus Dr., Ste L4, Dept. PE2, Costa Mesa, CA 92626 Service Questions 714 -708 -0610 Fax 714 -708 -0614 ,ublic service message 131

www.americanradiohistory.comAmericanRadioHistory.Com USE PE MARKET CENTER CLASSIFIEDS READ BY 87,877 BUYERS OF ELECTRONIC EQUIPMENT ACCESSORIES AND PARTS INSTRUCTION FOR PLACING YOUR AD!

HOW TO WRITE YOUR AD per ad per insertion (15 words). Any words that you want set in TYPE or PRINT your classified ad copy CLEARLY (not in all bold or caps are 200 each extra. Bold caps are 400 eách capitals) using the form below. If you wish to place more than one extra. Indicate bold words by underlining. Words normally written in ad, use a separate sheet for the additional ads (a photocopy of all caps and accepted abbreviations are not charged as -caps this form works well). Choose a category from the list below and all words. State abbreviations must be Post Office 2 -letter write that category number into the space at the top of the order abbreviations. A phone number is one word. form. If you do not specify a category, we will place your ad under Miscellaneous or whatever section we deem most appropriate. CONTENT All classified advertising in the PE Market Center is limited We cannot bill for classified ads. Payment in full must accompany to electronics items only. All ads are subject to the publisher's ap- your order. We do permit repeat ad or multiple ads in the same proval. We reserve the right to reject or edit all ads. issue, but in all cases, full payment must accompany your order. WHAT WE DO DEADLINES Ads received by our closing The first two words of each ad are set in bold caps at no extra date will run in the next issue. For example, ads received charge. No special positioning, centering, dots, extra space, etc. by November 13 will appear in the March, can be accommodated. 1995 issue that is on sale January 17. The PE Market Center is published monthly. No cancellations permitted after the closing RATES date. No copy changes can be made after we have typeset your Our classified ad rate is $1.00per word. Minimum charge is $15.00 ad. NO REFUNDS, advertising credit only. No phone orders. AD RATES: $1.00 er word, Minimum $15.00. Send your ads with payment to: Popular Electronics Market Center, 500-B Bi- County Blvd. Farmingdale, NY 11735 CATEGORIES 100 Antique - Electronics 270 - Computer Equipment Wanted 450 - Ham Gear Wanted 630 - Repairs- Services 130 - Audio -Video- Lasers 300 - Computer Hardware 480 - Miscellaneous Electronics For Sale 660 - Satellite Equipment 160 - Business Opportunities 330 - Computer Software 510 - Miscellaneous Electronics Wanted 690 - Security 190 - Cable TV 360 - Education 540 - Music & Accessories 710 - Telephone 210 - CB- Scanners 390 - FAX 570 - Plans- Kits -Schematics 720 - Test Equipment 240 - Components 420 - Ham Gear For Sale 600 - Publications CLASSIFIED AD COPY ORDER FORM Ad No. 1-Place this ad in Category #

1 - $15.00 2 - $15.00 3 - $15.00 4 - $15.00 29 - $29.00 30 - $30.00 31 - $31.00 32 - $32.00

5 - $15.00 6 - $15.00 $15.00 7- 8 - $15.00 33 - $33.00 34 - $34.00 35 - $35.00 36 - $36.00

9 - $15.00 10- $15.00 $15.00 11- 12- $15.00 37 - $37.00 38 - $38.00 39 - $39.00 40 - $40.00

Ad No 1 -Total words x $1.00 per word = $ 13- $15.00 14- $15.00 15 - $15.00 16- $16.00 All Caps words x .20 per word =$

17- $17.00 18- $18.00 19 - $19.00 20 - $20.00 Bold words x .20 per word =$

Bold Cap words x .40 per word =$ 21 - $21.00 22 - $22.00 23 - $23.00 24 - $24.00 TOTAL COST OF AD No. 1 $

25 - $25.00 26 - $26.00 27 - $27.00 28 - $28.00 Card # Total classified ad Payment $ enclosed. Expiration Date - _ / [ ] Check [ ] MasterCard [ ] Visa ($15.00 minimum credit card order) Signature

Name Phone

132 Address City State Zip

www.americanradiohistory.comAmericanRadioHistory.Com - Radiotelegraph DESCRAMBLERS DC /AC POWER Radiotelephone FCCCommercial $$$$ SAVE $$$$ INVERTER License 7 Specializing in r Why Take Chances? CANADIAN MARKET I Discover how easy it is to I I pass the exams. Study with the I Call us for all your most current materials available. Our Just plug the DC /AC Power Inverter into your CAR, Electronic needs RV. or BOAT cigarette lighter and you've got up to I Homestudy Guides, Audio, Video I 400 Watts of peak power (200W continuous)for your I pools make it so fast, AC- operated appliances! The DC /AC Power Inverter or PC "Q &A" I is perfect for TVs, VCRs. stereos. CD playes. com- easy and inexpensive. No college or Jolly R. Electronics puters. mobile phones. fax /copy machines, lamps. battery chargers. and hundreds of other AC -oper- experience needed. The new Visa, Mastercard, C.O.D. ated items. Features low battery alarm /shutdown. I FCC exams have been I high surge current capability. and modified sine commercial wave output for stable power source. NIGHER revised, covering updated Aviation, POWER UNITS ALSO AVAILABLE. 1 year warranty 1- 800. 279 -0614 I and 30 -day money back guarantee. Order tow! Call I Marine, Radar, Microwave, New for your FREE CATALOG! 9 -6 ht -F 10 -3 Sat.. EST Rules & Regs, Digital Circuitry & I ONLY $59.95 + S/H more.We feature the Popular A -Plus Electronics 1 -800- 877 -7587 I "Complete Electronic Career Guide" I 110-64 Queens Blvd. 1465. Forest Hills. NY 11375

1000's of satisfied customers II Control your project Guarantee to pass or money back. Send for FREE DETAILS or call I with a PC. Operate relays, 1- 800 -800 -7588 j motors, fans, lights etc. via the WPT Publications parallel port. No programming Save Big $ and watch what you want! 470) N.E. 47th Street Vancouver. WA 98661 necessary. Includes IBM comp- TV Name atible software and a step -by -step Cable manual. Send $29.50 to: Descramblers Address Project Solution Converters *Filters * Accessories City St. Zip Free Free Trial - NO RISK! L 1-800-800-7588 242 Ashboume Trail 30 day Catalog GA 30243 Unbeatable wholesale prices! Lawrenceville, Affordable extended warranty

(404) 963-6382 1 Year Warranty on all products £ JiI cahL nro/eio,mL CABLE Credit Cards Welcome! 11:11 HECT 1- 800 -379 -3976 CONVERTERS Rent NOW USA We'll beat anyone's price! J DESCRAMBit.ERS L755 AVAILABLE Prices starting VIDEO S?AnaáZERS SHARPER PICTURE CLEARER SOUND $699.00 as low as $99! FILTERS GREATER CHOICE U.S. CURRENCY Introducing the RCA brand ()SST' (Digital Satellite System) the ulti- +SOH AND RECEIVE mate digital entertainment expe- 1 MONTH rience. The advanced digital FREE iusSBi compression technology delivers HBO broadcast pictures with laser disc precision accuracy and CD -quality sound clarity All from a small 18" dish that can be easily in- SOLAR ELECTRIC PANELS stalled on your home or property RCA Brand DSS. The future of television today...and beyond! POWERGLASSTM $79.95 350 mA at 14.5 VDC 17.5" x16.0'x1.25" 3.8 lbs. FREI, ,REE Cable TV Catalog. POWERGLASSTM PLUS TFt1A $ 169.95 = m a 1.OAat14.5VDC Now you can tune -in your favorite Get copy of the cable TV programming and your 17.5" x16.0" x1.25" HANDBOOK SAVE S' 00'S - EVEN $1000'S CRYSTAL SET 4 lbs. on premium CABLE TV EQUIPMENT. Go back to antiquity and build the These affordable solar panels generate radios that your grandfather built. noise, Build the `Quaker Oats" type rig, useful electric power without wind coils that work and make it pollution, fuel costs, or electric bills. CVtOOERItI look like the 1920's! Only 510.95 Stop buying and throwing away han- plus $3.50 for shipping and Solar Photovoltaic ELECTRONICS dling. Claggk Inc., P.O. Box batteries. Start using 4099, Farmingdale, NY 11735 Electric Panels from SECO. USA Funds ONLY! USA and To order call 1- 800 -700 -1867 1-800-906-6664 Canada -no foreign orders. Visa /Master Card Accepted 2125 S. 156TH CIRCLE OMAHA. NE 68130 133

www.americanradiohistory.comAmericanRadioHistory.Com ADVERTISING INDEX POPULAR ELECTRONICS magazine does not assume any responsibility for errors that may appear in the index below.

Free Information No. Page Free Information No. Page ADVERTISING SALES OFFICE - A &D Electronics 129 - Intronics 129 Comeback Publications, Inc. A -Plus Electronics 133 116 - Jensen Tools 129 500 -B Bi- County Blvd. 125 Ace Communications 100 - Jolly R Electronics 133 Farmingdale, NY 11735 164 Advantage 1 Instruments 1I I - KDE ELectronics 127 -(516) 293 -3000 - Agrelo Engineering 114 38 Kelvin Electronics 105 Larry Steckler, EHF /CET President 26 Alfa Electronics 96 - M &G Electronics 126 28 All Electronics 104 160 MCM Electronics 123 Christina Estrada Assistant to the President Allen Engineering 125 - MD Electronics 97 Allison For Technology 116 - Mega Electronics 129 Advertising ONLY 516-293-3000 Alistar Electronics 129 149 Mendelsohn's - 117 Fax 1-516-293-3115 140 AMC Sales 117 - Mental Automation 121 Larry Steckler Andromeda Research 131 42 MicroCode - Engineering 103 publisher Antique Radio Classified 76 Modern Electronics - 133 Arline Fishman Basic Electrical Supply 115 Mondo- - - tronics 130 advertising director 161 Beige Bag 119 115 Mouser Electronics 29 Denise Mullen Black Feather - 128 167 National Electronic Wholesalers .. 7 advertising assistant - Bsoft 131 - Northeast Micro 131 Kelly Twist - C &C Electronics 126 - NRI Schools 35 credit manager C &C - Specialties 124 - Nu -Tek Electronics 4 132 C &S Sales 98 Ohio Automation 129 Subscription/ - Customer Service/ The Cable Outlet 114 43 - Optoelectronics CV4 Order Entry Cellsoft - 125 - Orion Electronics 133 1- 800 -827 -0383 - Circuit Specialties 101 148 Parts Express 129 7:30 AM - 8:30 PM EST CLAGGK, - Inc. 83, 90, 130 - PC Boards 118 Cleveland Inst. of Electronics 23, 71 PCW Technical Production 128 ADVERTISING SALES OFFICES - Command Productions 110 Performa Home 119 EAST/SOUTHEAST Comtrad Industries 8, 13, 17 Phillips Tech 124 Stanley Levitan - Consumertronics 118 47 Prairie Digital Inc 123 Eastern Sales Copyright Clearance Center 75 46 Print 115 1 Overlook Ave. Great Neck, NY 11021 - Cybermation 114 162 Print 120 1- 516- 487 -9357, 1- 516 -293 -3000 - Design Computation 127 Probemaster 108 Fax 1- 516 -487 -8402 EDE Spy Outlet 126 Progressive Concepts 126 MIDWEST/Texas /Arkansas/ EIA 27 - Project Solution 133 Oklahoma, Colorado, Arizona - Electronic Equipment Bank .... 107 RP Enterprises 114 Ralph Bergen 147 Electronic Rainbow 102 SECO 133 Midwest Sales Electronics Software Solutions 121 Self- Reliance Co. Inc. 125 One Northfield Plaza, Suite 300 Electronics Tech. Today.... CV3, 73 Show Time 121 Northfield, IL 60093 -1214 1-708-446-1444 Electronics Tech. Today 81, 87 Skyvision 128 Fax 1-708-559-0562 154 Foley -Belsaw Institute 29 Software Science 126 PACIFIC COAST /Mountain States Forest Electronics 119 Spy Supply 112 Fotronic Corporation 106 Tab Books 5, 53 Anita Bartman Hutch Looney & General Device Instruments 129 Tri Star Satellite Systems 133 Assoc., Inc. 6310 San Vicente Blvd. Get -Tech Inc. 116 163 Trisys 120 Suite 360

Grantham . College of Engineering 3 136 UCANDO Videos 127 Los Angeles, CA 90048 Great Southern Security 109 US Cable (Zentek) 117 1- 213 -931 -3444 Fax 1- 213 -931 -7309 - Greenleaf Electronics Inc. 110 US Cyberlab 110, 113 Halcyon - Group 118 - Vision Electronics 124 - Home Automation Systems 131 - Weeder Technologies 124 - I.E.C. 128 - Weka Publishing 113 Information - Unlimited 31 - WPT Publications 133 134 114 Interactive Image Technologies. CV2 134 Xandi Electronics 116

www.americanradiohistory.comAmericanRadioHistory.Com Hobbyist's Paperback Budget Books

cal Design BP271 -How to Ex- Popular 1 BP80 /98- Popular Design end L #160 -Coil BP276- Shortwave Electronic Electronic Circuits - ... s°o and Construction Man- pand, Modernize and Superhet Receiver Circuits Books 1 and 2...$11.90. ual...$5.95. A complete Repair PC's and Corn- Constructlon...$6.95. Contains a wide range of book for the home build- patibles...$7.75. All the Provides construction de- 4 circuits which are ac- er on how to make RF, practical information you tails, including coil wind- by text giving IF, audio and power are likely to need to up- ing, of a number of ad- ia" I` a brief introduction, cir- chokes and transform- - - grade your PC and cam- vanced- design receivers á cuit description and spe- ers. Practically every patible. Also contains which should have per- is V 1. useful information and il- ¢ r° .r.- cial notes on construc- possible type dis- formance levels at least tion and setting -up that cussed and calculations ? lustrations to help you equal to commercial sets may be necessary. are explained in detail. with repairs. of similar complexity.

SOProio°a #223-50 Projects Using IC BP122 -Audio Amplifier Con- BP107-30 Solderless Breadboard u.orerc 553130 ao SOU/MUSS CA3130...$5.00. One of the more prat- d'JDIo struction...$5.75. Practical designs are B.ED.OPXU Projects -Book 1...$5.95. Each project tical and useful operational amplifiers ''^Pr1niR featured and include circuit diagram and PROIEcis is designed to be built on a "Verobloc" CONSTRUCTION (opamp), the CA3130 integrated circuit , description, Veroboard or printed -circuit °`,' ' breadboard and is presented with a brief tf chip is the heart of several easy- to -as- board layout and construction notes. The circuit description, circuit diagram, com- semble projects covered in the book. text is divided into two parts. The first ponant layout diagram and components _ with many types of list. Notes on construction and applica- The projects are divided into five cate- , deals preamplifiers.r I I I goriest audio projects, RF projects, test The second covers power amplifiers tions are provided. Wherever possible, equipment, household projects and a from a simple low -power battery type to the components are common to several catch -all miscellaneous group. Ideal for á a 100 -watt DC- coupled amplifier using projects to keep project costs down. all skill levels. four MOSFETs in the output stage

BP266- Electronic BP329- Electronlc BP31 9-Making BP303- Under- Modules and Systems eirciro°m M °um Music Learning Pro- Mt,kin9 MS-DOS MS -DOS Work for You UNDERSTANDING standing PC Software For You for Beginners...$7.25. i-""'°9 r' ° }^." jects...$6.25. A begin- ' work -$6.50. What you need p SOFTWARE ...$6.95. Covers main of PC Shows the reader how to - - ner's book that will assist to know first, comes first, types software, build a number of simple -' you in assembling such i however the text is writ- giving details of typical analog and digital circuit projects as the Elexylo- ten in a circular style so uses, the basics of how modules, all suitable for I !r- phone, Gildaphone, 'i7 that the reader can they are used and their limitations. Each chapter ' battery operation, and all Melody Ranger, Cord- h ?+ anywhere in the text. c1u - ?' This book is relevant to covers popular software based on only 1 or 2 maker, Appealing Hand ', 0 l , ..: transistors or ICs. bells, Electronic Sol -Fa, all versions of both MS- and programs of a Simi- - .- Tune -up Box and more. DOS and PC -DOS. lar type.

BP105 Aerial (Antenna) Pro- Electronic i BP33- Electronic Calculator Users â= ;..._. BP125 -25 Simple Amateur Band [ter ú i P.oiecb db USA'. Plans build an- jects...$5.50. In this book the author has Ñ ;°F Handbook...$5.75. The book eliminates Arne.* Antennas...$5. 50. to considered practical antenna designs, in the mysteries of the calculator and of "40P tennas that are simple and inexpensive ideas for the simplest to most ' s' to construct and perform well. From the cluding active, loop and ferrite antennas 7 U q fers unique which perform well and are relatively sim- complex calculators. Covers the basic simple dipole to beam, triangle and even made from four TV ple and inexpensive to build. The corn- i 4 ß E functions plus trigonometric, hyperbol , mini- rhombic types ic, logarithms, square roots and powers / yip masts and about 400 feet of wire. After plex theory and mathematics of antenna ;° /7 the antenna discussion you will find a design have been avoided. Also included 1 Included are formulas and data for VAT / -s I \ are construction details of a number of o discounts, and mark up, currency con -' complete set of dimension tables that antenna accessories including a pre -se- version, interest, binary and octal num will help you 'tune" an antenna on a par - lector, attenuator and filters. bers, and much more! titular frequency.

l PCP104- Electron- BP302 -A Concise BP146 -The Pre- nand.. BP263 -A Concise oalas The pll introduction to Introduction to dBASE E \actE.P.^ ics -Build and Learn... Users Guide to Lotus prom W :!; BASIC Book...$6.95. dBASE ...$6.95. The most popu- a Em,^ $9.95. Construction de- ` °' °" " " " " " "'' 1 -2.3 Release 3.1... 'look :al Ju; Another book on BASIC . to help Illi r but with a difference. It lar data -base program, a k a" tails are given to build a $6.25 Written dBASE, is difficult to circuit demonstrator that existing spreadsheet concentratesonintro- -q!5 P4 Bd masterwithouthelp. This is used throughout the users upgrade to 1-2-3 k ;3411 ducing technique by 3.1, which has looking in depth at the ` y book helps you spend book to introduce corn- Release .o. I I your time using dBase. Ri mon electronic compo- the ability to work 3-di- ', §R most frequently used ¡I'- ICI and more easily under - not setting it up. A user's nents and how these mensionally with both . °o : . stood computer instruc- guide that covers all the .! components are built up multiple worksheets and Omrn011nt'ri III CBI R- lions. - basics up to dBase IV. to useful circuits. files.

Just What the Project Builder Is Looking For! #160 -Coil Design and Construction Manual $5.95 1596T -24 Silicon-Controlled Rectifier Projects $9.95 #219 -Solid State Novelty Projects $4.95 BP58-50 Circuits Using 7400 Series ICs $5.50 - #222 -Solids State Shortwave Receivers for Beginners...... $5.50 BP69- Electronic Games $5.50 r: #223 -50 Projects Using IC CA3130 $5.00 BP71- Electronic House Projects $5.00 #225-Practical Introduction to Digital ICs $5.25 BP84- Digital IC Projects $5.50 C PCP111- Electronic Test Equipment Handbook $13.95 BP93- Electronic Timer Projects $5.50

IN ELECTRONIC TECHNOLOGY TODAY INC. SHIPPING CHARGES SORRY No orders accepted Number of books ordered USA AND CANADA P.O. BOX 240, Massapequa, NY 11762 -0240 outside of USA & Canada $0.01 to $5.00 $2.00 $5.01 to $10.00 $3.00 Total price of merchandise $ Name $10.01 to 20.00 $4.00 Shipping (see chart) S Subtotal $ Address $20.01 to 30.00 $5.00 $30.01 to 40.00 $6.00 Sales Tax (NYS only) $ City State Zip $40.01 to 50.00 $7.00 Total Enclosed $ PE5 Allow 6 -8 weeks for delivery $50.01 and above $8.50 All payments must he in U.S. funds!

www.americanradiohistory.comAmericanRadioHistory.Com i Fish in< BLAST your way through the Frequency Spectrum Featuring the SCOUT and the OPTOSCAN456 Ct.tid

.7-50 MHz Marina 0500 MHz Universi ty Po-.ice

Ct+uise Line Charter Air

.5875 i #z Hardware Store ,5375 MHz Hardware Store CoMpa Poli er Compa

LOCHOUT EDIT RE ET i )olesaíe C Hardware St

WW1 TMP L O ? OPT I ON HELP :5 4%581,Silv Hardware St 6 uutwdiu STORE BAND

CLOSE NEW

MIA8

Each SCANBLASTER''" series SCAN&ASTER SCAYBLASTFR includes in the accessory set: IarIuIC,: c1n(1,,:

CX12A Computer interface S I Si"OUT;., 1\1C(I FM Notch ;ilter CtPT(A+SC ,c....st--orP Set - BLP-70 Low Pass F ilter Aeueti,cty Set ,111't BHP -800 ss Filter r $999 , ` S849 DB32 F \liniAntenna RD27 A ttenna RD440 440 MHZ Antenna RD 800 800 MHZ Antenna SCA N B1 ASTER ' " Ill SCA hBLAs TER Spectrum CD -ROM FCC Database 1 :_cludes: Utility Diak SCOUT Download Program U°GRAJE ) PTJSCAN45 6 ACI')0 Rapid Charge Adaptor Si t tn*, Accessory Set Cable /Adaptor SCOUT Reaction Tune <« X11 CC3I) Carry Case for SCOUT 3 YEAR EXTENDED WARRANTY S6)9

) F.L1A Ir r/ w I I m ® 800127..`

v,` FAX: 3i15-771-2052 5821 N :: lath Avmue Ft. Lauderdal ., 1.1. 33334 Contart Factory for shipping prices. Visa, Master Cat d, & C.O.D. (casit >r II on-) order onl3;

OPTCSC N456 _ softwareiV f4atured S'ANSTAR COMM '" Sur A uC al,u ao a lstblt from PRORt:,' SC A N( AT. SCANNI RADIO MGI,. 1+.R'vn, All price,,rt anJ>¡i i 1«tiui .; i ,uh¡ I ir :han, eeithuut not or 43 ON FREE INFOFilAT70NCqRD www.americanradiohistory.comAmericanRadioHistory.Com r