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www.americanradiohistory.comAmericanRadioHistory.Com MARCH 1995 Vol. 12, No 3 Popular Electronics

C O V E R S T O R Y

33 Build a Headphone Amplifier for your Guitar Prepare for your 'rock- and -roll" career, without annoying your family or waking up your neighbors, with this versatile headphone amp that even features special effects- Rodrick Seely

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

37 Build a Novel Nightlight Let the gentle glow of a vacuum tube light up the night -Larry Lisle

39 Getting Started in Surface -Mount Technology Learn how to work with surface -mount components when you build these two classic yet simple projects -Ronald A. Reis

51 Build a Frequency- Response Tester A welcome workbench addition for anyone who troubleshoots audio gear -Randy Constan Page 33

F E A T U R E S

46 SIM -EQ: The Simultaneous Equation Program Let your computer do the work -James E. Tarchinski

49 Exploring the ImagiNation Your computer comes alive with fun when you explore this on -line service -Donna Roach

57 Making Squarewaves at Home Page 37 Generating squarewaves is easy when you follow the recipes in this cookbook -Joseph J. Carr

-B Bi- County Boulevard, Farmingdale. NY 11735. Second - POPULAR ELECTRONICS (ISSN 1042 -170X1 Published monthly by Gernsback Publications, Inc. 500 issues, subscription rate U S and possessions $2195, Canada Class postage paid at Farmingdale. NY and at additional mailing offices One-year. twelve R125166280), all other countries $29 45 Subscription orders payable in U.S. $28 84 (includes G.ST. Canadian Goods and Services Tax Registration No $3 50. Copyright 1994 by Gernsback Publications, Inc. All funds only. International Postal Money Order or check drawn on a U S. bank. U5 single copy price by Gemsback Publications, Inc. Popular Electronics trade- rights reserved. Hands -on Electronics and Gizmo trademarks are registered in U.S and Canada Inc. is licensed to Gernsback Publications, Inc Printed in U.S A mark is registered in U S and Canada by Electronics Technology Today. and

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

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

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

www.americanradiohistory.comAmericanRadioHistory.Com M A R C H 1 9 9 5 Popular Electronics

P R O D U C T R E V I E W S Larry Steckler, EHF, CET, editor -in -chief and publisher

9 Gizmo EDITORIAL DEPARTMENT Carl baron, editor Magnavox CD -i player, Compaq Presario computer, Sharp Dan Koragiannis, associate editor portable music system, Desper Products Spatializer audio Teri Scaduto, assistant editor processor, and much more Evelyn Rose, editorial assistant Marc Spiwak, editorial associate 24 Hands -On- Report Joseph J. Carr, K4IPV, contributing editor Elenco Electronics Digital /Analog Trainer 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 6 Multimedia Watch Marc Saxon, contributing editor A multimedia monitor -Marc Spiwak John Yocono, contributing editor

28 Think Tank PRODUCTION DEPARTMENT Ruby M. Yee, Model- railroad circuits -John Yacono production director Karen S. Brown, production manager 64 Antique Radio Kathy Campbell, production assistant It's mailbag time again -Marc Ellis ART DEPARTMENT 68 Computer Bits Andre Duzant, art director Russell C. Truelson, illustrator Objects and hierarchies -Jeff Holtzman

Jacqueline P. Cheeseboro, 70 Circuit Circus circulation director Controller circuits Charles D Rakes - Michele Torrillo, POPULAR ELECTRONICS bookstore 76 DX Listening BUSINESS Shortwave from Austria -Don Jensen AND EDITORIAL OFFICES Gernsback Publications, Inc 500 -B Bi- County Blvd 78 Ham Radio Farmingdale, NY 11735

Some antenna topics- Joseph J Carr 1 -516- 293 -3000

FAX: 1 -516- 293 -3115 President: Lorry Steckler 82 Scanner Scene SUBSCRIPTION PC- powerful scanning -Marc Saxon CUSTOMER SERVICE/ ORDER ENTRY 1- 800 -827 -0383 D E P A R T M E N T S 7:30 AM - 8:30 PM EST Advertising Sales Offices 3 Editorial listed on page 128 Composition by Mates Graphics 4 Letters Cover by Loewy Design 73 Electronics Market Place Photo Illustration by Chris Gould 84 Electronics Library 43 ABC AUDITED 88 New Products Since some of the equipment and circuit- 97 ry described in POPULAR ELECTRONICS Popular Electronics Market Center may relate to or be covered by U.S patents. POPULAR ELECTRONICS dis- 128 Advertiser's Index claims any liability for the infringement of such patents by the making. using, or selling of such equipment or circuitry. 129 Free Information Card and suggests that anyone interested in such projects consult a patent attorney. 2

www.americanradiohistory.comAmericanRadioHistory.Com E A R N Y O U R EDITORIAL B.S. DEGREE IN HELLO DSS COMPUTERS If you were with us last month, you already know how I feel OR about my cable company. Because of that, I had long wanted to put in a satellite installation. Unfortunately, aesthetics (there ELECTRONICS was no getting around the need for an 8- to 10 -foot dish) and other factors (namely numerous trees) made that virtually impossible. That's why Thompson's DSS (digital satellite system) was like a dream come true.

For those of you still unfamiliar with it, DSS uses two (soon to be three) closely spaced, high -power satellites to beam roughly 175 channels of audio and video programming directly to consumers homes. The high power means that you can j use a small (18 -inch) dish, while the close spacing means that By Studying at Home you do not need an actuator to move the dish from one satellite to the next. Grantham College of Engineering, now in our 45th year, is highly experienced in "distance education " - teaching I've had my system for a little under a month now, and so far I by correspondence- through printed am very pleased with it. While not perfect, the video and audio materials, computer materials, fax, modem, and phone. quality far surpass what I was getting from cable, and should No commuting to class. Study at scheme is improve as a more advanced digital- compression your own pace, while continuing on your phased in early this year. As for programming, although I am present job. Learn from easy -to- complete and thorough paying a little less per month than I used to for premium cable, understand but lesson materials, with additional help I have picked up almost 125 additional channels, including 50 from our instructors. pay -per -view channels and 25 audio -only music channels; and Our Engineering Technology B.S. the number of channels is expected to expand still further Degree Program is available in either of during the year. Of course, there is also the initial outlay of two options: (1) The B.S.E.T. with Major Em- $699 to $899, plus installation costs. Due to high demand, phasis in Electronics, OR there is little if any discounting going on at this time. (2) The B.S.E.T. with Major Em- phasis in Computers. Our Computer Science B.S. Degree In deciding whether or not DSS is for you, there are a few Program leads to the B.S.C.S. -the -of -sight to downsides to consider. First, you need a clear line Bachelor of Science in Computer Science. the satellites. Second, if you want local programming, you will An important part of being pre- right need to either get it off -the -air or subscribe to your cable pared to move up is holding the degree, and the absolutely neces- "broadcast basic." The five major networks are also college company's sary part is knowing your field. available via satellite if you live in an area where over-the -air Grantham can help you both ways -to reception is not satisfactory. Finally, unlike large dishes, there learn more and to earn your degree in are no in- the -clear (unscrambled and free) signals. the process. Write or phone for our free catalog. Toll free, 1- 800 -955 -2527, or see DSS is an evolving technology, but the early results, and mailing address below. acceptance, are promising. We will be keeping an eye on it, as Accredited by well as other satellite -TV services, and are planning some in- the Accrediting Commission of the depth coverage for later in the year. Look for it. Distance Education and Training Council GRANTHAM College of Engineering Carl Laron Grantham College Road Editor Slidell, LA 70460 3

www.americanradiohistory.comAmericanRadioHistory.Com PINNING US DOWN A sharp -eyed reader spotted two errors in my article, LETTERS "Switching with PIN Diodes" (Popular Electronics, De- cember 1994). In Fig. 5, diode D3 is drawn in backwards. The believe that the use of a heat December 1993 issue of Popu- sound as if it is electronics. The "arrow" should point up. In Fig. sink for Q1 would be easier and lar Electronics. I was trying to learning will then be replaced by 7, diodes D3, D6, D9, and D12 more cost -efficient. According to get parts and a service manual a natural desire to know all he are also shown backwards. I the data in the November for my Gulbransen electronic can about the field, and it won't hope those errors did not cause December 1994 Digi -Key cata- organ. Health problems, both seem like learning at all. anyone too much confusion. - log, the IRFZ40 has an ID my wife's and mine, including a F.B. Joseph J. Carr. continuous rating of 35 amps, couple of small strokes, kept me Canada and a PD maximum rating of from my computer and from LOW -VOLTAGE POWER 125 watts. Even with derating to working on the organ. CONTROLLER one -half, heat sinking of Q1 I received letters from New MONITORING SOLAR would allow a current much York, Minnesota, We have been advised of a few and Missouri, FLARES larger than 4 amps. Also, for and even as far away as Puerto corrections for the article "Build Thank you for the article lower currents, the IRFZ20, at Rico. A gentleman a Low - Voltage Power Control- from Con- less than half "Ground Zero: The Other End of ler," the cost of the necticut even phoned and which appeared in the the Radio Spectrum" by Karl T. IRFZ40 and the IRFZ42, should offered to test the tubes, replace December, 1994 issue of Popu- Thurber (Popular Electronics, be an excellent choice. The them, and provide a service lar Electronics. First and October 1994). That is an area IRFZ20 is rated at 15 amps and manual! foremost, there has been a revi- that deserves more visibility. 40 watts. Because of the higher Again, thank you. You sion in the foil pattern for the can be Unfortunately, on resistance the information of the IRFZ20 (0.1 sure that any time I have a main board; the revised foil pat- contained in the section on so- ohm versus 0.028 ohm for the problem with an electronic de- tern is shown here in Fig. 1. lar-flare monitoring is a bit IRFZ40), a small heat sink vice, I will turn to Popular Second, the phone Fax number outdated -much has happened should probably be used if the Electronics for a solution. for the supplier, TW Engineer- since Chernan's book was pub- current is as high as 3 or 4 J.W.H. ing, has changed; the new lished. For readers who might amps. Leawood, KS number is 714- 527-2547. There be interested in this fascinating The article presents an excel- were also a few typographical area, I would like to direct their lent idea. I have never seen a errors: In Fig. 1, pins 6 and 7 of attention to Peter O. Taylor's similar DC power controller, and LEARNING VS. U2 -b are reversed; in Fig. 4, book, Observing the Sun I can think of several uses for TEACHING connection points Pl and P2 (Cambridge University Press, one. I think most of the con- are reversed; and in the parts This letter is in response to the 1991). The author is the chair- struction articles (and others) in list, D2 should be specified as a letter by A.S. from Taneytown, man of the Solar Section of the Popular Electronics are good, 1N751 Zener diode. We apolo- MD, which appeared in the De- American Assocation of Varia- although I frequently make gize for any problems those cember 1994 issue of Popular ble Star Observers (AAVSO), minor changes in the projects, errors may have caused. Electronics. I cannot claim to and his book covers - which (I think) are improve- electronic Editor fully understand the U.S. edu- ments. solar -flare observation as weil cational system, nor will I as visual B.S., CET techniques. Peter Tay- I am writing Fazal about A. pretend to. I wish to state, how- lor leads an active network o: Rehman's Hillsboro, MO article, "Build a Low - ever, that claiming that amateurs who, with simple ra- Voltage Power Controller" (Pop- trigonometry and complex al- dio equipment, monitor and ular Electronics, BELATED December THANKS gebra are not important in report solar -flare activity. Those 1994). I am wondering about the today's I'm offering a very belated society is pure non- observations currently make .ip use of multiple IRFZ40's for sense. There are virtually thank -you for publishing my no more than 70% of all stations currents of more than 4 amps. I engineering fields "Haves & Needs" letter in the -electronics reporting data to the National among them -in which you are Oceanic and Atmospheric Ac- not required to use those ministration (NOAA). Thus, it s branches of mathematics. an excellent way for electronics No one is forcing the writer to hobbyists to make very useful forget his skills; it is solely his contributions to science. responsibility that they remain The AAVSO observers re-

strong. Most teachers I know do ceive regular reports that their absolute best when it summarize all contributions, as

comes to teaching, and I have well as a technical newsletter yet to see one who will not that describes new receiver cir- answer a question that is off the cuits, antennas, computer - beaten path of what is currently based and electromechanical being taught. I believe that the data recording methods, sur- writer has a bad attitude when it plus- equipment conversion, etc. comes to learning or just is not Mr. Taylor has also published interested in the subjects being related information in taught. Perhaps both. My advice Communications Quarterly. for him is to find a field that S.H. 4 FIG. 1 grabs his interest -it does not Amherst, NH

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By Marc Spiwak For a long time, basic neat zoom feature built -in. sion. But Phoenix is much computer peripherals That eliminates the need to more than just a joystick. performed the same old reposition and resize the That bizarre -looking con- functions. A keyboard was picture for different ap- troller combines a joystick, c just a keyboard, a modem plications. throttle and rudder control- was just a modem, a The speakers are not self - ler, and 24 programmable monitor was just a monitor, amplified, so you need buttons all in one unit. The and a joystick was just a some kind of amplification, buttons can be set to ex- A Multimedia joystick. But at some point, either from a sound card ecute any joystick or various kinds of pointing de- with a built -in amp or a keyboard command. The Monitor vices started to appear on separate add -on one. buttons can also serve pri- keyboards and fax ca- While the speakers are not mary and secondary pability was added to the kind that an audio en- functions, for a total of 46 modems. thusiast (or loud -music customizable functions. The Today we also have listener) will want, they are unit ships with pre- config- monitors with speakers built - more than adequate for ured control settings for in, just like they are in a TV the average guy or gal many popular games, and set. Specifically, I am now who just wants to enjoy a custom settings can be little multimedia, as well as saved to disk. for most business -audio ap- Phoenix can control so plications. many functions because it The best thing about the connects to both the Audio 15's speakers is that joystick port and the key- they don't take up any extra board connector. A Phoenix space on the desktop, connector plugs into the

which I know is always a keyboard connector on

very crowded place. I your PC, and your keyboard would not be surprised if plugs into the end of the eventually all monitors have Phoenix connector. built -in speakers, and audio Phoenix has a list price of enthusiasts will simply buy $149.95. For people who better ones just as they al- want the utmost in flight ways have in the past. realism and control con- The Audio 15 has a sug- venience, there's nothing gested retail price of $499. like a Phoenix. Street prices, of course, will surely be much lower than NEW STUFF that. This month I have a few discs that are particularly A NEW CONTROLLER useful to the staff here at The Audio 15 from Tatung adds a pair of speakers to an excellent I mentioned before that Popular Electronics. The 15 -inch computer monitor. It makes for a near -perfect multimedia at one time, joysticks were first one, Books in Print Plus workstation. simply just joysticks. But I've from Reed Reference Pub- played with some unusual lishing, is basically a testing out a new 15 -inch joystick-like controllers re- database of all books that monitor from Tatung, the cently, including the new are in print. Naturally, the Audio 15. Besides having a Phoenix flight- and weap- power of a computer and nearly flat screen and a ons- control system from a CD -ROM make it easy to crisp, clean picture, the Au- Advanced Gravis. To start find what you are looking dio 15 has built -in stereo with, Phoenix includes Grav- for. Books in Print does not speakers. The digitally con- is' usual high -quality joystick come cheap, though. A 6 trolled monitor also has a control with adjustable ten- year's subscription to the

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Troubleshoot down to the The Encyclopedia of Science component level - ariy and Technology is a component! Verify poorly comprehensive reference narked parts, test for toler- work that includes 7,300 ances and damage. Wavetek's articles and more. new DM27XT is not only a full - function DMM, but also the disc sells for $1,095 for includes complete inductance, regular version and $1,595 capacitance, and frequency a year for the version that measurement capabilities. includes 238,000 book reviews. Pricey as it is, it is Wide LCR range: mighty useful. 10 0 to 2000 MS2 The second disc that's 10 pF to 2000 pF pro- 100 pH to 20 H useful in the everyday t,, duction of a magazine like frequency mV V Autoranging pA mA A this one is the McGraw -Hill 10 Hz to 20 MHz kHz MHz meter II Mil Multimedia Encyclopedia .BAT nF to 20 A of Science & Technology for Ac and do current LOGIC -04 a) MAX Windows. That disc includes Logic test, diode test, max 7,300 articles, 105,100 terms, reading hold, continuity and 122,600 definitions beeper, input warning from 81 major subject beeper, fused input I areas. It is loaded with pic- protection, battery saver 000 = tures, audio, and video. This V 520 20 with , disc is also an expensive Consolidate your test bench 2 one, priced at $1,300, but it one meter that does it all - 200m A high -performing, is an exceptionally useful Wavetek's 200m disc to have on hand for full -function XT Series DMM. 20m 20A anyone who can afford it, It's all in one compact, rugged, 2m as it contains information field -ready package with a big j' on almost any conceivable 0.7 -inch, 31/2 -digit display. 200µ and alligator 2n technical or scientific top- Insulated probes '_. ic- including electronics. clip leads are included, and 20n The third disc is a year's there is a huge selection of _. 2µ current, 200k 20µ worth of Ziff-Davis' PC Mag- accessories, including F 2 )k 200 :coo azine on CD- ROM -the rf and HV probes, temperature converters, holsters, and cases. complete text of 22 issues. DM27XT Ask for Wavetek DMM5. They're While I prefer to read the printed version of the mag- the meters to pick when you azine, the CD -ROM version have things to fix. is the best way to look up information on a particular subject or product that has been covered within the

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www.americanradiohistory.comAmericanRadioHistory.Com rine mammals. It seems WHERE TO GET IT that The Discovery Channel plans on producing lots of Advanced Gravis new CD -ROM's #101 -3750 North Fraser Way on various Burnaby, B.C. topics. One of them, Canada V5J 5E9 Normandy-The Great Tel. 604 -431 -5020 Crusade, is certainly history - CE3 Incorporated related. That disc chronicles 3134 Pacific Coast Highway D- Day -June 6, 1944. That's Suite 216 the day that Allied forces Torrance, CA 90505 invaded Tel. 800- AutoDisc the beaches of Normandy in order to liber- Discovery Enterprises ate Europe and crush the 7700 Wisconsin Avenue Bethesda, MD 20814 Third Reich. Two other new Tel. 301- 986 -1999 discs have less to do with history Future Vision Multimedia and more to do with 300 Airport Executive Park the neat stuff you see on Nanuet, NY 10954 The Discovery Channel. An The Phoenix flight and weapons control system from Advanced Tel. 914- 426 -0400 Interactive Journey With . . Gravis is a game-player's dream come true. LucasArts Entertainment Sharks is an entertaining Company look at those creatures that all deal with history in P.O. one and culture from prehistoric Box 10307 have roamed the seas for way or another. The San Rafael, CA 94912 first times to around 1840. The 400 -million years. Tel. 415- 721 -3300 Beyond one, America's Civil War-A is disc a wonderful study aid Planet Earth takes you on Nation Divided, McGraw -Hill from Soft- for history students and his- an interactive journey Professional Book ware Marketing torians, alike. It has a retail Group through 11 West 19th Street the heavens. Corporation, is a complete price of $99.95. New York, NY 10011 I like cars -I've been in- collection of Civil War trivia Leonardo The Inventor, Tel. 800-722-4726 terested in them for as long presented via stories, pho- from Future Vision Multi- MPI Multimedia as I can remember. If cars tos, videos, narrations, media, is about one man 16101 South 108th Avenue are also your passion, this maps, and more. All of the who made his own histo- Orland Park, IL 60462 month I have Iwo discs that major players are covered. ry Tel. 708 -460 -0555 -that man being you won't want to miss. Any war buff or person Leonardo daVinci. Many of Reed Reference Publishing The 1994 Auto Almanac needing to research the 121 daVinci's inventions, or vi- Chanlon Road from CE3 Incorporated war between the states New Providence, NJ 07974 sions, while unused in his contains over 2,000 pages should check out the Tel. 908 -464-6800 disc. It time, have come to pass in of automotive information. retails for $59.95. ours. His many Software Marketing accomplish- There's almost a quarter - The next Corporation disc deals with ments can be explored million vehicle specifica- history on a much larger through animations 9830 South 51st Street and Building A -131 tions and prices, photos, scale than just one war. The more on this disc that's a lot Phoenix, AZ 85044 video, and more. The 1995 Story of Civilization, from of fun Tel. to play with. 602-893-3377 version should be out by World Library, Inc., is Will Another disc is or was - Tatung Inc. the time you read this. The and Ariel Durant's compila- history in the making. A 2850 El Presidio Street disc has a suggested retail tion of more than Long 3,000 Hard Day's Night from The Beach, CA 90810 price of $14.95. Voyager Tel. 213-979 -7055 Company is the The second disc on cars complete The Voyager .._2.Y and uncut Beat- Company is called Cars! Cars! Cars! les 578 Broadway, Suite 406 movie in QuickTime for and is published New York, NY 10012 by MPI Windows format with lots of 212 -431 -5199 Multimedia. The disc is extras thrown into one CD- loaded with videos, photos, World Library, Inc. ,, .. ROM. While it better to see facts, wJl v,d M:d ITuu 2809 Main and trivia on all kinds the movie Street on the big Irvine, CA 92714 of cars ranging from dream screen, The Story of Civilization the disc includes Tel. 714 - 756 -9500 cars to racing cars to wacky stuff that might covers more than 3,000 years be hard to Ziff -Davis cars, and will be enjoyed of history on a single CD- find elsewhere, such as the One Park Avenue by any car buff. ROM. original script New York, including de- NY 10016 Last this month is a new Tel. 212 -503 -5100 leted scenes, the theatrical screen saver from LucasArts years of history on a single trailer, and more. Beatles called Star Wars Screen En- multimedia CD -ROM. The fans will probably want this a disc published by The tertainment. The software full text of all 11 volumes of -ROM CD in their collection, Discovery Channel, In The comes on floppy discs, but the Durant's work, including simply because it's the Company Of Whales; it's an is great nonetheless. At over 800 illustrations, audio, Beatles. entertaining multimedia $35.95, it's a must -have for 8 and video, details history A while back, I looked at look at those unusual ma- fans of the film.

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IA CHRONICLE %Itit) OF CONSUMER ELECTRONICS

Video CD -i

MAGNAVOX CD1450 COMPACT DISC - INTERACTIVE MULTIPLAYER WITH ADD -ON DIGITAL VIDEO CAR- TRIDGE. Manufactured by Philips Con- sumer Electronics Company, One Philips Drive, Knoxville, TN 37914 -1810; Tel. 615 -521 -4316; Suggested retail price: $299; Digital Video Cartridge: $249.

We've always said that when we have kids, there will be no video games allowed in the house. Sitting zombie -like in front of a TV, controller in hand, cannot be a positive, life -enhancing way for kids to spend their time. Shouldn't they have some better things -sports, reading, playing, chores -to do? Will they ever do anything else if video games are around? After all, we -and our editors-are well aware of the fact that we've yet to meet a deadline when we've had a game ma- CD has been de- chine in for review. And we're "responsi- a quarter of the size and a third of the price cast standards, Video multiple ble adults." What effect would vid- of the original. The 11.75 x 7.5 x 2.6 -inch signed for compatibility with dedicated eogames have on our kids' homework player carries a suggested retail price of playback platforms, including compatible assignments? $299. Video CD players, Video CD- CD -i players Well, if the system is Philips' Magna- It offers all the functions of the original computer systems, and Video Car- vox CD1450 or CDI550, it's possible that player, with a very special optional equipped with the Digital CD -i players those school assignments would be im- bonus -a Digital Video Cartridge that al- tridge. The new generation of on proved. Compact Disc -Interactive, or CD- lows the CD -i unit to play full -length fea- are the first-and, so far, only-devices be used to play Video i, is more than just a game system. It's an ture films and advanced action games. The the market that can videos. interactive "multiplayer" that can be used add -on cartridge (Model 22ER9956) re- CD movies and music players are also blessed to research term papers (with an interac- tails for $249.95, and can easily be The new CD -i available software, tive encyclopedia); improve one's tennis plugged into a slot on the top of the with an abundanc., of since the or golf game (with interactive sports in- CDI450 by the user. The step -up model which has grown substantially three years ago. structions); play audio CD's; view Photo CDI550 comes with the Digital Video Car- product was introduced re- The is bundled with "Interna- CD's; watch full -length movies in full - tridge already installed, at a suggested CDI450 and the CDI550 with color, full- motion video; and, of course., tail price of $499. tional Tennis Open," hit., Ace." Both players play games. The Digital Video Cartridge is based on the arcade "Space CD -i version of Compact Disc- Interactive has been the MPEG -1 international standard, de- also come with the Interactive Encyclopedia." evolving rapidly since its market introduc- veloped by the Moving Picture Experts "Compton's well as the quantity, of tion about three years ago (see Gizmo, Group. It delivers computing performance The quality, as improved; many newer February 1992). In fact, the latest genera- of 400- millions instructions -per- second the software has have been specifically designed to tion of CD -i products bears little outward (MIPS) with multiple RISC (reduced in- titles of CD -i's full- motion vid- resemblance to its earliest ancestors. struction -set computer) processors. The take advantage Philips' software division, The first CD -i players were full -sized result is a 5 -inch disc that contains more eo capabilities. created four pub- components, designed to look like every- than 72 minutes of 30- frame -per -second, Philips Media, recently Games, Family En- thing else in your entertainment center. full -motion digital video, along with CD- lishing subdivisions -- Entertainment, and And they bore a hefty suggested -retail quality audio. tertainment, Home of which has been busy 9 price tag-$1000. The CDI450 is less than Independent of NTSC and PAL broad- Video CD-each

www.americanradiohistory.comAmericanRadioHistory.Com creating new CD -i titles. More than 150 (An optional splitter allows two -player titles are currently available, including play with the addition of a second control- new releases resulting from Philips' agree- ler.) A 12 -foot cord allows freedom of ments with such major motion -picture stu- movement while playing. The controls are as dios MGM /UA and Paramount. A found on the rounded section that tops a review of some assorted CD -i software fol- narrower grip. At the center of the round lows our look at the latest hardware. section, a circular, directional thumb -pad The CDI450 and CDI550 are virtually moves the cursor up, down, left, right, identical; the only difference is that the and, in some programs, diagonally across Digital Video Cartridge, which is included the screen. To either side of the thumbpad with the latter, must be purchased sepa- are action buttons. rately for the CDI450. The top of each CD- The controller is fairly accurate and i player contains two covered compart- easy to use. We had one problem with it, ments. The smaller one, on the left side, however. We tended to accidentally hit the holds the plug -in Digital Video Cartridge. left-side action button while working the To the right is the larger disc compart- The two- player version of International directional controller, with the unfortunate ment. The only thing on the front of the Tennis Open is included with the result of inadvertently exiting a game - unit is the input for the wired game con- CDI450. usually at a crucial point. troller. The power switch is found on the Several optional CD -i controllers -a left side panel. The rear panel contains a co-I joystick, a mouse, a trackerball, and a jack for the outboard power supply and a World of mf muri.Onl'wrTk.úien roller controller -are available. We tried set of three RCA phono jacks for con- out the Model 22ER9017 joystick, which necting the CD -i multiplayer to a TV and, carries a suggested retail price of $29.95. if desired, a stereo audio system. That controller has a more traditional look; Installation of the Digital Video Car- COMPTON'S designed for two -handed play, it has a tridge is simple. With the player switched joystick on one side and four action but- off, the disc compartment cover is opened INTERACTIVE tons on the other. Traditional with a twist, to reveal latches used to remove the cover ENCYCLOPEDIA that is: The optional controller is adaptable of the Digital Video Cartridge compart- for left- or right -handed play. The player ment. A special, pen- shaped tool is then can hold the controller with the joystick on used to remove a protective metal cover the right side, or flip it over so that the from the connectors within the compart- joystick is on the left. When a slide switch ment. The cartridge plugs into those con- is also "flipped," the controls are reversed nectors, and the compartment cover is PHILIPS COMPACT DISC INTEAACTIVE as well, so that pressing the joystick for- replaced. Because the Digital Video Car- ward Including "Compton's Interactive still makes the cursor move up or tridge also contains memory that is re- Ency- clopedia" with the CD -i player will make forward. The four buttons on the other side quired for some programs and games, parents view it as more than just a game of the controller are actually two sets of A removal is not recommended unless repair system. and B buttons; they are in the proper places is required. no matter which way the controller is held. When the CDI450 is turned on, an The model 22ER9017 gave a finer de- opening screen appears on the television than others -a 14- year -old relative using gree of control to game play. It also totally screen. It contains the Magnavox logo, a CD -i for the first time never even glanced eliminated the problem of hitting the small box that notes the time and date, an at the instructions, yet he easily beat our wrong button at an inopportune time. indication if a disc is in place or if the disc high scores on every game!) The CDI450 comes with "International compartment is open, and a bar labeled We were particularly impressed with the Tennis Open" and "Compton's Interactive "Options." Clicking on the options bar quality of CD -i movies. The video was not Encyclopedia." The tennis game allows opens the options screen, which is used for laserdisc quality, but it was easily equiv- you to assume the persona of Victor Player, CD audio play, setting the time and date, alent to VHS tapes, and the digital audio a promising young hopeful just starting and storage of audio and Photo CD pro- sounded every bit as good as a CD or out on the pro circuit. Player strives to win grams. laserdisc. The full- spectrum sound was the three major international Tennis Open To play a CD -i disc, the disc compart- most obvious on "Star Trek IV: The Un- Championships, held in London, New ment is opened by pressing on the front discovered Country." When the Enter- York, and Paris. On the way, he trains and edge of the cover. The cover gradually prise's engines were placed on warp speed, plays "friendly" exhibition matches opens to a 60° position, where it remains they could be felt, as well as heard, against four top players-Julio Jimenez, until the disc is in place and the cover is throughout the viewing room. (Don't Thomas Ullman, Erik Andersen, and pressed closed. An LED flashes while the throw out the old VCR yet -the CD -i Robert Garrett. This two -player game also disc is starting up, and remains lighted movie selection is still pretty limited, al- allows competition with a friend. At the while the disc is in play. though several new ones are in the works.) end of each match, Player receives his In- Each disc contains a brief set of instruc- The full- motion video capability also is ternational World Partner player ranking. tions. Further help is often available on- used to enhance some CD -i games, many We wish we'd had "Compton's Interac- screen, if needed, although most play is of which require a Digital Video Car- tive Encyclopedia" back when we were in largely intuitive. (More so for some people tridge. For instance, the adventure game school, writing reports. Not only is it "Dragon's features Gizmo is published by Gernsback Publica- Lair" motion -picture much more convenient than going to the tions, Inc., 500 -B Bi- County Blvd., Farm- style animation, and the interactive drama library and hoping that none of the other ingdale, NY 11735. Senior Writers: Chris F. "The 7th Guest" uses real actors in ghost- 29 kids in the class, all with the same O'Brian and Teri Scaduto. Copyright 1995 ly digital video sequences. assignment, were using that volume of the by Gernsback Publications, Inc. Gizmo is a The game controller included with the printed encyclopedia -it's also more inter- 10 registered trademark. All rights reserved. CDI450 is a wired, one -person device. (Continued on page 19)

www.americanradiohistory.comAmericanRadioHistory.Com The Mazemaster, you must complete a maze be used to enhance game playing. is -colors bright, CD -i Games level within a pre-set time limit, or guide animation excellent all four purple balls home before the blue motion seamless -as is the accompanying People Play ball. soundtrack. The game requires speed, "The 7th Guest" ($59.98) is one of timing, and cunning, as the wizard attacks those "interactive dramas of mystery and in various unexpected ways. Dragon's Lair CD-i SOFTWARE ASSORTMENT. Pub - intrigue" that leave us totally baffled. The was created by Don Bluth, who is best lüshed by Philips Interactive Media,11311 double -disc set takes place in the haunted known for the arcade hit Space Ace. Santa Monica Blvd., Suite 400, Los An- mansion of toymaker Henry Stauf, who "Litil Divill" stars Mutt, a little demon geles, CA 90025; Tel. 310 -444 -6600; disappeared a couple of months before the who has been "volunteered" to navigate Price range: $20 to $60. start of the game. He has invited six guests through a winding obstacle course called the to a party at his home, and none of them The Labyrinth of Chaos to retrieve The following are some admittedly sub- Mystical Pizza of Plenty. Players must jective reviews of several CD -i titles from guide Mutt through five levels of in- each category. They represent each catego- creasingly difficult game play, all the Games. ry produced by Philips Media: while avoiding a wicked character called Family Entertainment. Home Entertain- The Entity, who tries to whisk Mutt off to a ment, and Video CD_ Where available, torture chamber. Poor Mutt suffered prices for specific games are included. mightily at our hands-being beaten by a club -wielding monster, and repeatedly GAMES drowning while trying to cross a river- We are no experts when it comes to video- gaming, and our tastes differ from the average gamer. For instance, we tend to steer clear of any games that feature graphic violence and are won by brute force. And we've yet to play one of those interactive drama/mystery games to a successful conclusion -we just don't have the patience. However, we do get hooked on are ever seen again. The player takes on the those games that combine strategy and persona of the 7th Guest, "a mysterious timing. entity known only as Ego ... [whose] role, identity and purpose is not shown or explained, but is rather experienced as a seamless, integral[ part of the total environ- ment." The goal is to explore the mansion, obtaining clues by solving puzzles and viewing dramatizations of the missing even when we switched to the upgraded guests. Perhaps if we'd had more time or game controller. "Litil Divil" also uses patience, we'd have done a bit better:, as it the Digital Video Cartridge, and has the is, we gave up after solving only a few enhanced video and audio to show for it. puzzles. A Digital Video Cartridge is required, and results in video quality that far FAMILY ENTERTAINMENT surpasses that of any of the other platforms By "family entertainment," Philips on which we've seen the game. Media means software for young children. "Dragon's Lair" ($49.98) pits Dirk the In this category, there is no violence, and Daring against a host of villainous obsta- the emphasis is on learning. cles as he battles his way through the evil Keeping those criteria in mind, it's not wizard Mordroc's castle to rescue the love- surprising that our favorite game by far - ly Princess Daphne. This game, which and the reason for this month's missed also requires a video cartridge, is an excel- deadline -was "MegaMaze" ($34.98). lent example of how full- motion video can To be fair, its packaging did contain a clear 41.0 tat game was highly addic- warning that the , o tive. Aimed at players aged 10 to adult. MegaMaze is essentially an electronic version of one of those handheld mazes in which you must guide a small ball into a if Ake, hole by tilting the board. The CD -i adds some twists, however, including purple balls, which also move as you tilt the "hoard" but which explode on impact and PHILIPS COMPACT DISC INTERACTIVE can destroy the blue ball that you are trying Bears on Their Own to get "into the vortex." Then there are "The Berenstain for ages 4 sink holes, and laser guns, and trap doors, and You on Your Own" ($39.98, skills" such as and, well, you get the picture. There are: 75 and up) teaches "school and the like, but its main levels of increasing difficulty, with a total counting, colors, responsibility. The proof 165 mazes. To reach the rank of emphasis is on 11

www.americanradiohistory.comAmericanRadioHistory.Com TECHNOLOGY UPDATE

World's first wireless home theater system makes professional -quality surround sound affordable... Now you can add surround sound to your home entertainment lineup with the amazing new Chase Technologies decoder that works with your existing stereo and an assortment of wired and wireless speakers. by John Lindner

Let's face it. As much fun as renting a like you're actually there when events are hap- video can be, it's just not the same as pening. Now there's an incredible new device seeing a movie in a theater. I remember that lets you use your stereo receiver to get the first time I saw Jurassic Park -I nearly that same surround sound in your home. jumped out of my seat when the dinosaurs The secret's in the signal. To get sur- roared. One of the reasons movies seem so round sound, you need to do more than real is because surround sound makes it seem simply add extra speakers. There needs to be a way of separating the signal from the musi- The secret of surround cal score or movie soundtrack into distinct sound channel for each speaker. The new Chase Surround sound has become the rage of the Technologies HTS-1 surround sound decoder '90s because it adds depth and realism to does just that, and in a revolutionary way that stereo sound, giving you the home theater rivals the best Dolby Pro-Logic and THX sys- experience. In short, it makes you feel like tems available today. you are actually at a concert a theater. Wins over critics. In the September 1994 To get surround sound, some people issue of "High Performance Review," noted have tried simply adding additional speak- audio critic Daniel Kumin said "the HTS-1 can ers to their home entertainment lineup. But do quite a job of recreating a 3D theatrical exit takes more than additional speakers to get perience...surround effects emanated with sat- surround sound; there needs to be a way of isfying fullness...sound was clean at any separating the original signal into distinct level... with quite involving channels so that you're not just duplicating and natural sound ambience." the same sounds and broadcasting them Plus, from different areas of the room. John Sunier, a leading authority on surround sound The new Chase Technologies HTS -1 sur- and producer of Audiophile round sound decoder does just that. and in Audition, a nationally syndi- a revolutionary way that rivals the best Dolby cated radio program for au- Five channel options. The HTS-1 decoder Pro -Logic and THX systems available.The dio enthusiasts, says, "...the can be used with two, three, four or five chan- HTS -1 provides five channels of sound from The new HTS-1 new Chase HTS-1, when used nels of amplification, making it the most cost any two -channel stereo source. decoder won to decode the hidden ambi- effective method for upgrading your stereo The HTS -1 works with a variety of speak- the Design and ence in all musical recordings, system to full home theater performance on ers. In the front, you can use your existing Engineering definitely outperforms all the the market. Best of all, the HTS-1 works with stereo Award speakers. For the rear. choose from at the Dolby and THX processors a variety of hard wired and wireless speakers. inexpensive wired Consumer speakers. high -quality (which could cost you up to In the front, most people use wired stereo wireless speakers. Electronics or even an audiophile - $3,000)...I am impressed!" speakers. Use your existing stereo's Show for being speakers quality wireless satellite subwoofer system. or use one of one of the Decoding breakthrough. a variety of wired speakers. The HTS -1 also gives you the ability to add best and most Last year, audio industry vet- Comtrad also offers the Chase Dialog center a powered center channel speaker (instead innovative eran Bob Rapoport invented a channel speaker. If your front speakers are of using your Tv's built - new products. new five -channel more than eight feet apart, in speaker). "passive" The Chase HTS-1 circuit for decoding the Dolby adding a center channel speaker will help keep decoder is Surround' signals in every stereo, videotape the most cost - voices and sound effects or laserdisc. This passive method is superior effective method centered on the to active decoders such as Dolby and THX be- screen for for upgrading stunning localization cause it requires no AC current to decode. As and an existing clarity. a result, you experience more clarity, more de- The Dialog is self stereo system to tail, and a greater sense of space. Plus, you powered and video shield- full home theater won't experience the noise or distortion which ed to prevent interference performance can occur with active decoding methods. You with your television set. on the market. don't need any extra amps! Just connect the HTS-1 to your stereo, add your speakers, and you'll experience the magic of home theater at a fraction of the cost of other systems.

www.americanradiohistory.comAmericanRadioHistory.Com Speaker Options Wired Speaker Options

Front Speakers: The Chase HTS -1 surround sound decoder can utilize your existing stereo speakers, or any of a variety of wired speakers available through Comtrad or your local electronics dealer. Center channel speaker. lf the front speakers are more than eight feet apart, adding a center channel speaker will keep voice cues centered on the screen. We offer the Dialog. It is self -powered and video shielded to prevent interference with TVs. Dialog $75 $8 S &H

Rear channel speakers. We recommend the quality Chase ELF -1 in either white or black for inexpensive rear channel speakers. Mount them with the enclosed color -matched mounting brackets or flush mount them on the wall. ELF -1 $99 /pair $10 S &H Wireless Speaker Options

Rear channel speakers. Recoton W440 wireless speakers are the perfect option for people who want quality stereo rear channel speakers without having to run speaker wire. Their two -inch tweeters and four -inch woofers deliver 10 watts per channel -clear, strong stereo fill sound. The speakers work up to 150 feet from the transmitter without loss of sound quality. T51000 transmitter 1f $7 S&H (works unlimited speakers) $69 W440 wireless speaker (each) $89 $9 S&H

Get the Chase HTS -1 half o f ($49) when you buy the W440 speaker system!

Rear channel speakers. For true audiophile-quality rear channel speakers, we offer the Recoton wireless satellite subwoofer system. This first- of -its- kind system combines a 10-inch rear- firirg subwoofer with a pair of 25-watt The subwoofer pro- The rew Chase Technobgies HTS -1 satellite speakers. vides that distinctive "low -end punch" surround sound decode gives you that you feel in movie theaters, while the ootion of using eith -sr tradition- the satellites are designed to coincide al wi-ed speakers like the Chase with surround sound processor specifications balance per- ELF -'s, or using wireless speakers fectly with the front speakers. W14T470 transmitter... $69 $7 S &H $24 S &H or a wireless satellite subwoofer WHT421 wireless 50-watt subwoofer $299 wHT462 pair of wireless 25-watt satellite speakers $329 $24 S &H system for additional convenience and enhanced sound quality. Get the Chase HTS -1 FREE when you buy the satellite subwoofer system!

Wireless freedom. When it comes to rear Audiophile quality. For the true stereo en- connect speaker wire to the front and rear speakers, you can again choose standard thusiaEE t, we offer the Recoton self- amplified speakers. When using wireless speakers, con- trans- wired speakers like the Chase ELF -1s. But if wireless satellite subwoofer system. The satel- nect the transmitter to the output. One you want to avoid the hassle of running speak- lite speakers in the system each bolster 25 mitter will broadcast to each wireless speaker. er wire up and down walls, behind furniture, watts of clean, distortion -free sound. The sub- Risk-free home trial. The best way to eval- and under carpet, you can add the freedom woofer adds a whole new dimension to your uate surround sound is in your home -not a and convenience of wireless speakers. home theater with its 50-watt amplifier that's showroom. That's why we're offering the 30- capable of creating enough rumble to make Try these products in Recoton wireless speakers utilize a trans- day risk -free home trial. you feel like you're in the home and if you're not delighted with mitter which broadcasts sound signals up to The Recoton your middle of an earthquake. the the surround sound experience, return 150 feet through walls, floors and ceilings. The wireless sub - a Questions Asked" refund. speakers can be placed anywhere; they plug woofer's 50-watt Even the most discrim- them for full "No into a standard electric outlet. This eliminates 10 -inch speaker inating surround sound HTS -1 surround sound decoder $99 $10 S &H need to have wires running from the stereo delivers thunder- enthusiast will be en- the Please mention promotional code 711 PL1111. to the speakers, which can be a nuisance with ous bass that gulfed by the abundant -free 24 hours a day surround sound since the rear speakers are adds depth and power and delighted with For fastest service call toll often elevated or wall mounted. realism to the the full- range, first -rate surround sound sound from these black 800-704-1211 Affordable option. Recoton 's W440 speak- experience. oak vinyl veneer speakers. E+mRE to add wireless rear channel = [12 Zito ers allow you Every speakers without compromising the sound Easy to install. To order by mail, send check or money order for the total quality that wired speakers deliver. Each self - speaker option offered by amount including S6H (VA residents add 4.5% sales tax.) Or charge it to your credit card, enclosing your account amplified speaker contains a two -inch tweet- Comtrad can be easily in- number and expiration date. er and four -inch woofer. They deliver 10 watts stalled with the HTS-1 in a per channel for strong, clear fill sound. Their matter of minutes. Just CQNITAAA compact design (9" high x 6" wide x 5.5" long), connect the speaker out- INDUSTRIES make them the perfect bookshelf -sized com- puts of your receiver or 2820 Waterford Lake Drive, Suite 106 panion to your home entertainment set up. amp to the HTS -1, then Midlothian, Virginia 23113

www.americanradiohistory.comAmericanRadioHistory.Com gram has two distinct parts: a cartoon, and won't get bored quickly. The Digital Video a self-paced tour of Berenstain Bear coun- Cartridge is recommended but not retry. In the cartoon, the two Berenstain cubs quired; with it installed, the video quality want to go to the Country Fair by them- was excellent. selves. Before their parents will grant per- mission, the cubs must prove that they can HOME ENTERTAINMENT behave responsibly, by completing a list of Philips Media Home Entertainment chores and challenges -get ready for produces a wide variety of adult interactive school on time, go to the market, share, titles. By "adult," they mean programs of etc. Further lessons in responsibility are interest to grownups. "Time -Life Astrolo- found in the "on your own" segment. As gy," for instance, offers customized the players travel through the bear's house, astrological information for every day of the market, the school, the park, and the the year, draws astrological charts, pro- fair, they learn important safety tips and vides personal horoscopes, and offers play learning games. Successful comple- compatibility reports. "Titanic," takes tion of the games earns them gold stars, as players on a tour of the ill -fated ship, nar- well as tickets to the fair, where they can rated by Star Trek's Patrick Stewart, that explore the possibilities of the format, play still more games. The story is charm- includes more than 2500 historical photos, which would put 135 minutes of video, ing, and there are plenty of activities to actual ship diagrams, videos of the re- preferably of laserdisc quality, on a single keep kids busy. This version does not re- discovery of and more recent exploration 5 -inch disc. Philips and Sony are currently quire the Digital Video Cartridge. of the wreck, and storylines of actual pas- collaborating on a digital video system, as The "Hanna- Barbera Cartoon Car- sengers and crew members. are Toshiba and Time Warner. nival" ($39.98) brings back some fond In the meantime, however, Philips Me- memories for Baby Boomers who grew up dia's Video CD Group was the first to re- with the Jetsons, Top Cat, Yogi Bear, the lease full- length movies and music videos Flintstones, and the other characters fea- on five -inch CD's. The video CD-i discs tured on this disk. Each cartoon character can hold 72 minutes of VHS -quality vid- has his own "booth" at the interactive eo, along with CD- quality sound, so most carnival. The player (aged 6 and up) is movies come on two -disc sets. The plat- challenged by a different game at each form also allows publishers to include booth -guide Scooby Doo through a such "value -added features" as behind - maze, help Fred Flintstone catch balloons the- scenes information about the film and even on -screen sales of tie -in merchandise (parents, beware!). The CD -i player allows customized control over the viewing experience. Via an on- screen panel, the Video CD viewer can select slow motion or freeze-frame with continuing sound, as well as fast forward, The only Home Entertainment title that remote, and pause modes lacking the jitter we received for review, however, earns its associated with VCR's. It's also possible "adult" label in more ways than one. "The to skip forward or back to a specific scene Joy of Sex" transforms Alex Comfort's in the movie, conveniently listed classic book into an interactive in the sex man- table of contents. ual, complete with full- motion video (Digital Video Cartridge required), ex- plicit line drawings, and partial nudity. While some segments are certainly titillat- ing, the disc is not about gratuitous sex. Aimed at couples in committed, monog- in a butterfly net, match colors at amous, loving relationships, it looks at sex Huckleberry Hound's Gift Emporium and from the points of view of four people -a sounds at Yogi's Pic- a -Nic. (Top Cat's triv- twenty- something man and woman who ia game reminded us just how long ago it each miss the passion of the honeymoon was that we watched those Saturday morn- phase, and a man and woman in their ing cartoons!) Some of the games seem fifties who would like to rediscover sex designed to hone the youngster's gaming from a more mature perspective. "The Joy skills in preparation for the more sophisti- of Sex" tries to help those four represen- cated games he or she will be playing a few tative people make the most of their sex all about US years down the road. For instance, the lives through expert advice, game playing, PHILIPS VIDEO CD young gamer must help George Jetson quizzes, drawings, and video. navigate his space car past dangerous as- In "Star Trek VI: The Undiscovered teroids while trying to pick up stray satel- VIDEO CD Country," as the Federation and the lites. Every time the player wins a game, Video very CD could well be the wave of Klingons are preparing for a "glasnost - he is awarded a letter on the "Cartoon the future. Recently, seven major motion - like" peace summit, Captain Kirk and the Carnival" banner. When the banner is picture studios -Disney, Warner Broth- crew of the Enterprise (they're baaack) are completely filled in, the player is rewarded ers, Columbia Pictures, MGM, Viacom, accused of attacking a Klingon vessel. The with a short cartoon. Each game has sev- MCA/Universal, and Paramountjoined CD -i version of the film provides video 14 eral increasingly difficult levels, so players together in an "ad hoc advisory group" to (Continued on page 19)

www.americanradiohistory.comAmericanRadioHistory.Com Family Computing

COMPAQ PRESARIO CDS 520. From Compaq Computer Corporation, P.O. COMPAa Box 692000, Houston, TX 77269 -2000; PRESARIO Tel. 713 -370 -0670. Price: $1699. 500 SERIES

Choosing a TV or home -theater system is confusing enough for most consumers-in fact, it can cause severe anxiety attacks. If you make the wrong choice in 1111211y ,® home-theater equipment, you can simply - chalk it up to experience. But if you make the wrong choice when buying a computer 1 for your family, you might permanently ban them from the heralded information 1 Alai I 1 1 1 has{rl superhighway! a I',I1+'fÌTlel°r r, r r .Ìii r Back in the early 1980's, everyone pre- r_r ,I 1-3:14 . LCL x,t. dicted a home -computer revolution. Even r though millions of computers were sold, the revolution didn't happen back then. The incompatibilities between the com- software is provided with puters that were sold, and the growing eliminates the need for a disk controller, communications system other than the Terminal pro- pains of the industry were only partially to local -bus video card, fax/modem, sound the gram that is part of Microsoft Windows. blame; the main reason was that the com- card, I/O card, and CD -ROM controller. It easy to build a computer that can puters weren't powerful enough for the (The CD -ROM drive is run from the hard isn't at a local mainstream mass market. What was drive's IDE controller.) be purchased as a commodity store, taken out of the box, and set up powerful enough for many business uses The case can accept two 3/4- length ex- even by someone who has just couldn't provide entertainment. pansion cards. It wouldn't take much to successfully used a computer before. But build- Today, of course, things are quite a bit run out of expansion slots. If you installed, never ing such a "family" computer is exactly different, as can be seen with the latest for example, a video -capture card and Compaq sought to do with the Pre- computers introduced by Compaq. We ex- PCMCIA adapter, you'd have no room what which is now available in more than amined the base entry model of the com- when you went to install a network, radio, sario, stores across the country. pany's new introductions, the Presario or TV card. Because the case offers only 5600 is packaged in a single, CDS 520. three drive bays-which are already oc- The system with un- intimidating pho- Just what is an entry-level computer to- cupied by the floppy- and hard -disk drives large carton of a father and son building a day? The CDS 520 is powered by a as well as the CD unit-an expansion to tographs while referring to software 486SX2 processor running at 66 MHz. include, for example, a tape -backup drive model airplane historic aircraft. If everything The 486SX does not have a math would require an external case. describing to plan, the largest prob- coprocessor. However, according to Corn - Although those somewhat limited ex- goes according someone will have setting up the paq, it performs 26% better than a pansion capabilities would be cause for lem that is getting it out of the box. For 486DX2/50 in most Windows applica- concern to us, we doubt its important to Presario the only other require- tions. The computer contains a single, most new users, who probably have no hardware setup, to plug in the cables for the high- density, microfloppy disk drive; a intention of ever opening the computer ments are mouse, and telephone line. double -speed CD -ROM drive; a built -in case. keyboard, is a breeze because of clearly sound card; and speakers. A Fax/modem The Presario CDS 520 is equipped with Even that -panel jacks. Purchasers who and speaker phone are also standard. a generous bundle of software, including labeled rear intimidated might find some com- The standard configuration for the CDS MS -DOS 6.2 and Microsoft Windows 3.1. are still fort in the VHS videotape that is included 520 is 4 megabytes of RAM (which is Application programs shipped with the unit. installed directly on the motherboard). computer include Microsoft Works for with the event that any problems occur, Our machine was equipped with 8 mega- Windows, Quicken for Windows, Micro- In the does offer a free (and toll -free) bytes; the machine can be expanded to 64. soft Encarta CD, Kidsoft CD, the Home Compaq -hour technical hotline. Be prepared to The Presario CDS 520 has a unique all - Survival Toolkit, and The Even More In- 24 wait for the service, however. In random in -one design; everything except for the credible Machine. In short, there's some- calls, our wait times -when we didn't lose keyboard and mouse are contained in a thing for every member of the family. patience and hang up- ranged from 10 single package with a small footprint. Be- Some utilities are supplied expressly for minutes to about 40 minutes. cause of that, a Presario setup can be sur- the Compaq machine, including the Wel- the computer is out of its box and prisingly neat. Neat enough, for example, come Center/Control Center /Learning Once plugged in, and the keyboard, mouse, and to be kept in the family room. Center, and Compaq Utilities. Startup phone line are attached, the power switch To keep the size of the unit down, Com- kits, which provide one month's free ser- be turned on. Setup software that is paq came up with an interesting configura- vice (but which also require that you sub- can installed on the hard disk takes care of the tion. First, the unit has no plug -in cards scribe by entering your credit card The user is asked for his or her lan- installed. All of the features that would number), are provided for America rest. and country. When selected, the normally reside on plug -in cards are in- Online, CompuServe, Prodigy, and the guage software is installed (de- 15 stead integrated on the motherboard. That Imagination Network. Unfortunately, no appropriate

www.americanradiohistory.comAmericanRadioHistory.Com In our opinion, Compaq would have 42 served its customers better by including all of the installation software on a CD -ROM iE ! iE ? instead of on the hard disk. The software that the setup program installs is a collection of programs that a family will likely find useful along with some software that is probably of little use,

:1 and some demonstration packages that might whet a family's appetite to buy more. The Documentation supplied with the CDS 520 should help most beginning computer users get familiar with the system. The default configuration for the machine is to boot up running Windows. In- stead of the Program Manager that is the default shell of Microsoft Windows, the Presario loads TabWorks, an alternate shell. Although there is nothing inherently wrong with TabWorks, it doesn't seem to provide any better interface than the de- The Presario does its best tomake even computer neophytes feel comfortable with the fault Program Manager shell. If someone system. TabWorks (top left) ds a replacement for the Windows Program Manager. The in the family is somewhat familiar with Phone Center (top right) is easy enough for anyone who has ever used a traditional Windows through exposure to it at work or phone. The sound -system controls (bottom left) also mimic real audio components. school, TabWorks An "operator" (bottom right, tries So guide users along. could be a detriment to learning how to use the computer efficiently. Fortunately, Compaq makes it easy to switch between the TabWorks and Program Manager shells. The CDS 520 offers energy-saver power-management options. During periods of inactivity, the monitor and hard disk can be turned off to conserve power. A strike of a key or movement of the mouse restores the computer to full operation virtually immediately. The monitor comes up to full brightness in only a matter of seconds; the hard disk takes a little longer to come up to speed. The time -out settings for the monitor can be set in five -minute intervals from five minutes to a half hour, and the hard - disk time -out can be set in one -minute intervals between ten and twenty minutes. The energy -saver feature can be turned off if it is not needed. Because the system looks as if it's off when in its sleep mode, the user can choose to have the power LED blink. The Presario's motherboard contains many of the functions that would normally be An interesting and useful feature of the incorporated on separate plug -in cards. For upgrades, the motherboard simply slides Presario is a built -in, full -duplex speak- out in a drawer from the main chassis. Note the clearly labelled input and output jacks. erphone, with an answering machine that can be set up with individual voice mail- compressed) from the hard -disk drive. The applications, including Microsoft Win- boxes for family members. Although the software that is configured for other lan- dows. If power were turned off (or lost) speakerphone performance was sur- guages is deleted. The entire setup process during installation, it would likely cause a prisingly good, we were happy that a takes about 35 minutes. The only other fatal error. If files became corrupt, a user handset could be plugged in for more pri- questions that the user needs to answer is would have no way to correct a problem vacy. for printer setup. unless he or she had done a full backup. When we initially saw the Presario CDS Although the software installation is (As with most computers, a practical 520, we thought that it would be fine for straightforward and almost foolproof, it backup system isn't included with the non -serious users, but unsuitable for per- does present some potentially serious CDS 520 except to floppy diskette.) Even a forming serious tasks. We no longer think problems. Most of the software is con- full backup, however, doesn't give a user that, and, despite some limitations, would tained only on the hard disk; no installa- the same flexibility to correct a problem as feel comfortable recommending the ma- 16 tion diskettes are supplied for most of the having installation diskettes. chine to most families.

www.americanradiohistory.comAmericanRadioHistory.Com Slip Slidin' Away

WQ -CH800 PORTABLE MUSIC SYS- TEM WITH FIVE -DISC CHANGER. From Sharp Electronics Corporation, Audio Division, Sharp Plaza, Mahwah, Nj 07439 -2135; Tel. 1- 800 -BE- SHARP. Price: $249.95.

Most of us associate portable music with the Walkman-pocket- sized, light- weight, and private. But there are times when we'd like to take music with us, and still be able to share it with friends. That's where the boombox comes in. Aimed primarily at teenage and twenty- something males (who tend to prefer their music loud, and are strong enough to lug around a good -size portable music system), the boombox can be carried from a dorm room to the park or beach. It allows the listener's choice of music to be heard radio, into the program mode, and the program by anyone in the immediate vicinity. inch woofers flank the CD changer, indicator appears in the display. To select Today's portable stereo systems often and tape deck. a each song, first the disc number button is incorporate a CD player, along with the The back panel is stark. It contains pressed, and them the up /down buttons are requisite AM /FM radio and tape deck. headphone jack, the input for the included used to reach the desired track number. A Some even offer CD changers. AC power cord, a flip -up telescoping an- second press of the MEMORY button stores Sharp's WQ -CH800 is a portable stereo tenna, and a large battery compartment the track in memory, and the programmed system with a unique five -disc changer. that holds the eight D -size batteries re- number will appear in the display. The discs are loaded label- side -up into the quired to power the WQ- CH800. By Repeat play can be used to repeat all the top of the unit. The changer mechanism Loading the CD player is a breeze. tracks on every disc in the disc holder, or to slides the stored discs to either side of the pressing the disc select buttons in order repeat a sequence programmed using center position. To move a CD into play (one through five), you can position five APMS. Pressing the PLAY /REPEAT button position, the changer glides to the left or discs in the changer. Each disc is placed on is twice causes all the tracks on all the discs right to pick up the selected disc. The its tray, and when the next button whisks it in the disc holder to be repeated. If the labels of the discs remain face up and visi- pressed, the tray lifts the disc and load PLAY /REPEAT button is pressed twice when ble as they pass through the system. The off to the side. You're then ready to When all five are loaded, the a sequence of tracks has been programmed time needed to change from disc 1 to disc 5 the next one. manually. (the program indicator will be lighted), is an impressively quick 4.7 seconds. CD compartment lid is closed that sequence will continually repeat. The WQ -CH800 is about the size of To play a disc, you simply press its Other CD functions include Auto Pro- many of today's mini, bookshelf stereo number to move the CD into the play posi- Playback gram Search System (APSS) and cue -and- systems. It measures 211/4 x 103/Ie x 91/4 tion and press the PLAY button. review. APSS automatically locates the inches, and weighs in at a hefty 15 pounds. automatically begins with the first track on beginning of the next track. Cue and re- A handle folds up from the top to facilitate the first disc and proceeds in order through view allows you to fast forward audibly to carrying. The CD changer also is set in the the tracks and discs, unless you opt for one reach a specific portion of a track. top of the unit. Three windows allow you of the available playback options. se- The tuner is the weakest section of the to view the disc in the play position and Those options include disc-number play, WQ- CH800. Tuning is manual, not dig- those in the top slot on either side of it. CD lection, direct- selection play, random ital, so it is not as accurate and, of course, controls include track- selection buttons Automatic Programmable Music Selec- tion (APMS), and repeat play. Any disc it is not possible to store station locations (numbered 1 -5), and PLAY and STOP or in memory for immediate access. buttons. number can be selected during playback by The dual -cassette deck allows you to The front center section of the boombox when the changer is stopped, simply button. record from the CD, radio, or tape 1 to tape contains a small display that indicates the pressing the desired disc number track 2. A synchronized recording system disc and track number, and mode or pro- It's also possible to select a specific makes it easy to record from the CD player. gramming information when applicable. on any disc in the disc holder, by pressing the up When the RECORD button on the tape deck To the left of the display is a four-band first the disc number and then using track and the PLAY button on the CD player are graphic equalizer; to the right are the re- or down button to choose the pressed, recording begins automatically. maining CD controls. number. simply The tape stops when the disc ends or is The tuner is centered on the front panel, Random play is programmed by either during stopped or paused. Pressing the STOP/ with the rotary VOLUME and TUNING knobs pressing the RANDOM button The random EJECT button of the tape deck ends the placed to its left and right. Just beneath the playback or in stop mode. random play recording session. Although continuous radio dial is a four-position slide switch indicator will light up, and playback (from tape 1 to tape 2) is possi- that doubles as a power switch and func- will begin with the next track, in any ble, only tape 2 can be used for recording. tion selector. The dual -well tape deck is Up to 32 tracks can be selected sequence That means that the WQ -CH800 can't be located below the tuning dial, with tape order to create a programmed button used to record long radio programs on two controls arrayed along the bottom of the using APMS. Pressing the MEMORY tapes, for instance. 17 front panel. Two -way speakers with four- while in stop mode puts the WQ -CH800

www.americanradiohistory.comAmericanRadioHistory.Com The heart of the board is a 20 -pin integrated circuit mounted on the bottom of the board. The bypass switch on the EMR 4.0 demonstration board also switches the chip between its three separate Spatializer

modes: Type E (Spatial Expansion), Type D (Directional Positioning), and Type S (Spatial Synthesis). Spatial Expansion enhances and ex- pands the sound from normal stereo recordings and requires only two speakers. Although centered images remain in the center, off-center instruments and sounds are expanded so that hard -panned images sound as if they originate from locations SPATtALt2ER well outside the speakers, and even around AW)O Proussor t7orpr Progt:pb. too. the listener. That is the mode that, say, TV- TilaPhprross3+0) 200-3700 or set or boom-box manufacturers would use (03) 7270-0O4s(TatcYO) if they choose P.^' worw-«as to incorporate Spatializer } technology in their products. The Directional Position mode is essentially the same as Spatial Expansion. In fact, the mode switch is left in the same position for either mode. The Directional Position mode, however, requires addi- Spacing Out You may have, in fact, already encoun- tional circuitry that is not included on the tered one form of the technology, the PRO demonstration board, notably pan pots Spatializer. The professional system was such as those found on a mixing console. SPATIALIZER EMR 4.0 AUDIO PRO- used, for example, to mix the audio for The pan pots provide the ability to locate CESSOR. Manufactured by Desper Disney's The Lion King, some of the per- and move individual sounds up to 270 de- Products Inc., 11400 West Olympic formances on the MTV Music Awards, grees around the listener in real time. As Blvd., Suite 1100, Los Angeles, CA Bonnie Raitt's latest album, and many the sound is panned from one side to an- 90064; Tel. 310 -268 -2700; Price: N /A. others. The Pro Spatializer allows record- other, it moves outside the speaker bound- ing engineers to place audio from any re- aries and around the listener. Stereo, it seems, just can't cut it any cording track in 3- dimensional space. One use for the Type D mode would be more. Surround sound is no longer limited Spatialization is a one -way process - in computer videogames, where the soft- to movie releases and instead is being used that is, Spatialized program material does ware equivalent of pan pots would position more and more in the recording studio. not require a decoder for the effects to be the sound in relation to game play. Ac- The booming popularity of surround heard. It was possible, for example, for us cording to Desper, multiple sounds can be sound is now included in most main- -it to experience the Spatializer's effects with directionally positioned. However, each line stereo receivers testament -is to the a demonstration CD that contained A/B would require its own pan pot (or software tact that three-dimensional ambience is comparisons between Spatialized and equivalent), and the outputs of all the po- here to stay. non -Spatialized recordings. The CD pro- tentiometers would be summed together. Audio -equipment manufacturers have vided some insight into how Spatializer The final operating mode is Type S or long sought a way to get the performance can work. Spatial Synthesis, which provides a of a surround -sound system from a single Even more convincing, however, were pseudo -stereo image with mono inputs. pair of speakers. Various strategies have the effects produced by Desper's Spa- Because much multimedia sound is mono, been developed through the years to extend tializer EMR 4.0 Demonstration Board, this mode should be effective in providing the sound beyond and behind the loud- which is designed to demonstrate the new greater depth and realism. speakers and to add a third dimension of EMR 4.0 integrated circuit. Matsushita As mentioned earlier, the intent of Spa- depth to audio. In other words, to improve Electronics Corp., a subsidiary of Mat- tializer technology is to create an ex- the stereo process so that its reproduction sushita Electric Industrial Company, the panded sound stage from a single pair of duplicates what you might hear in a live consumer electronics giant whose brands stereo speakers. The effect is intended to performance. include Panasonic, Technics, and Quasar, be more than simple expansion, and in- Desper Products, Inc., has developed a is manufacturing the EMR 4.0 IC under stead closer to surround sound. new audio -processing technique called license for Desper Products. The chip will Previous attempts that we have heard Spatializer that promises to add another make it easy for manufacturers to incorpo- from other companies had drawbacks dimension to audio so that sounds seem to rate Spatializer technology into a wide ranging from an ill -defined sound stage to come not only from beyond and behind the range of products. a small "sweet spot" to mono incom- speakers, but from in front of them as well. The demonstration board accepts a ster- patibility to a sound that was simply un- In a departure from what we normally do eo signal input via board- mounted RCA - natural. In contrast, however, Spatializer here at Gizmo, we will not review a Spa- type phono jacks. It provides a stereo out- works amazingly well. tializer equipped product as much as we put, as well as an optional surround out- We auditioned Spatializer with a variety will describe Spatializer technology, put. It is powered by a 9 -volt battery, and of program material and a variety of hard- which you are bound to encounter fre- contains a power switch, a bypass switch ware. We sampled, for example, stereo quently in consumer products in the com- that permits A/B comparison, and a poten- television broadcasts on a run -of-the -mill, ing years. 18 tiometer that allows the effect to be varied. 26 -inch, stereo TV receiver with small,

www.americanradiohistory.comAmericanRadioHistory.Com You can search for a topic by typing it in on the on- screen keyboard, by scrolling through an alphabetic list of all articles, or by using the Topic Tree Fact-Index. The Topic Tree breaks down all of the major articles on the disc into menus of topics and subtopics for easy reference. The Fact - Index includes close to 30,000 short articles on a wide range of subjects, as well as thousands of references to articles. Select- ing the "jump" icon in the Fact -Index will call up the main article on that subject. The Time Machine lets users select past eras in history and learn about major events and life during that time. Our review unit also came with an assorted sampling of CD -i titles -several games, a couple of movies, a few sports programs, and some kiddie titles. (Re- views follow.) Unfortunately, the interactive encyclopedia was the least frequently used title in our house-as we suspect it might be in most homes. The encyclopedia is a tremendously technology is already in use in a variety of products. The PRO Spatializer Spatializer useful information resource. And its inclu- recent CD releases including a box set of the original Woodstock album, was used in CDI450 might make parents new releases from Bonnie Raitt and Barbara Streisand to name a few. Hardware sion with the and video games products that contain Spatializer include a Panasonic boom box and a unique multi- more willing to bend the "no media sound board from Multiwave Innovations. in this house" rule. But, in reality, CD -i remains a high -tech video -game player sume, is how Desper came up with the and, with the added Digital Video Car- Spatializer name. tridge, movie playback system. According to the company, the effect is the equivalent of op- obtained by creating GAMES PEOPLE PLAY tical illusions for the human ear -brain page 14) mechanism. The position of a sound (Continued from source is determined from several clues, such as the phase difference between the and audio quality far superior to that of the sound at each ear. Humans instinctively VHS tape we'd rented several months ear- and instantly perceive the sounds and re- lier. The disc comes with "liner notes" audio processor is avail- The Spatializer flections of sound to determine the dis- about the making and makers of the film, a 20 -pin surface -mount inte- able in and size of sound sources. and an "About the Cast" section that fea- grated circuit. tance, location, Spatializer technology will never re- tures biographies similar to that found in a playbill. built -in speakers. Because of the limited place Dolby Surround, but it is completely theater All About Us" ($24.95) distance separating the speakers, stereo compatible with Dolby Surround and it "Peter Gabriel: behind- the -scenes look at the performance was really in name only. With should make itself useful in many applica- provides a award- winning music videos, the EMR 4.0 installed, the speakers no tions where the expense of surround sound musician's "making of" footage, video longer seemed to be located in the TV and the requirement of rear speakers make including with Gabriel's pro- cabinet. Instead, they shifted far to the left it unjustifiable. Spatializer technology clips, and interviews team. Viewers learn, for instance, and right. would make sense in a TV set in a bed- duction sound how the special- effects team created the In one test, we placed dummy speakers room or dorm room where surround The illusion of snails crawling across Gabriel's at various locations along the front of the would normally not be considered. how it was possible for his head to room and asked subjects to pick the speak- computer multimedia market is already in- eyes and appear as if it emerged from a speeding er pair that they thought they were listen- corporating Spatializer in its products. has train. In exclusive interviews, Gabriel re- ing to. By varying the space control-and Multiwave Innovations, for example, veals his motivation for lyrics, personal therefore the Spatialized soundstage -we incorporated the chip in its new Command Boom moments in his life, and his feelings about could position the sound so that it seemed 3 -D Sound Engine audio processor. the the state of the world and the human con- to emanate from the dummy speakers. Our boxes could benefit immensely from The Video CD features the music test subjects, who were unaware of what technology, as could many television sets. dition. benefit videos "Digging in the Dirt," "Steam," we were doing, confirmed that Spatializa- Audio /video receivers could also to the DSP "Blood of Eden," and "Kiss that Frog," tion was doing its job. from Spatializer as an addition from the CD "Us." It also features music We found that it was possible to adjust features that are already incorporated. videos for songs from the "Passion" CD, the ((space)) control until the sound be- including "Come Talk to Me" and came unnatural, but it was also possible to VIDEO CD -i "Zoar," as well as a music video from the create a very pleasing performance. The page 10) (Continued from 1977 hit, "Solsbury Hill." An on -screen Spatializer processor varies not only the function panel gives viewers complete in- width of the soundstage, but its depth, as esting and, yes, even fun to use. It offers teractive control of the viewing experi- well. The soundstage becomes a true videos, audio selections, pictures, photos, ence. 19 three- dimensional space, and that, we pre- maps, and a built -in dictionary and atlas.

www.americanradiohistory.comAmericanRadioHistory.Com GIZMO NEWS

Audio on Demand Stop That Car! that can be set up to "interrogate" vehi- A unique combination cles. Vehicles with of existing tech- Almost anyone who's ever received a the proper code will nology promises pass over to create a new way for speeding ticket has fantasized that he or the device safely. information There junkies to get their fix. The she could have outrun the cops if he or she is no firm word when those de- Information Highway vices will Media Corporation had really wanted to. Such thoughts re- be available to law- enforcement of Cupertino, CA is planning to launch its main fantasies for most rational people. agencies. The company, which is head- Audio -On- quartered Demand subscription service. Even so, high -speed auto chases occur fre- in Sleepy Hollow, Illinois, is The seeking service will allow users to select quently, resulting in thousands of acci- venture capital investment. from a wide variety of audio program- dents each year. Consumer Electronics No -Show ming, and store the programming on a In the future, new anti -vehicle elec- The Consumer Electronics Show - Inter- pocket -sized device. Up to ten hours of tronic countermeasures -or AVECM, as active (CES -I), which was scheduled to be personalized programming can be ob- their creators like to call them -will offer held in May in Philadelphia, has been can- tained in about five or six minutes. It can a way to catch fleeing suspects without a celed. Gary Shapiro, vice president of the then be played back through a car stereo chase. According to Creative Electronics Electronic Industries Association Con- system or through a portable audio device. Consultants, small, portable electronic sumer Electronics Group, said, "After re- The programming that will be offered devices that are capable of disabling the viewing the pressure and stress put on will consist of audio versions of news- engine operating system of a pursued vehi- potential exhibitors, buyers, and jour- papers, magazines, and books, as well as cle will bring it to a standstill within sec- nalists to decide between two major indus- radio programs, special- interest program- onds. Those devices are, according to the try shows being held at the same time, on ming, and even TV audio. company, "a promising alternative to con- two separate coasts, we chose to do what The audio will be sent in digital form to ventional barrier technology." was best for the interactive industry and reschedule our show in 1995 to 1996." CES- Interactive was the scheduled replacement for the Summer CES that was traditionally held in Chicago in late spring. CES -I has been rescheduled to be held in Orlando in May 1996. The other industry show to which Shapiro was referring was the Electronic Entertainment Expo (E3) that will debut in Los Angeles from May 11 to 13-the same days that CES -I had been scheduled. The E3 show will focus exclusively on the development, marketing, and merchandis- ing of software titles for all game platforms and CD systems. Following the EIA decision, the orga- nizers of E3 (the Interactive Digital Soft- ware Association or IDSA) released a statement saying, "We believe this is the right decision for everyone involved and are pleased to have the matter finally re- solved. It underscores the coming of age of the $8 billion interactive entertainment industry, which has long needed to make a statement of independence with its own dedicated Listen Up audio receivers. The primary The device is a pancake -like disc with a show." means of distribution will be through ca- diameter of 42 inches and a height of about Strong Sales ble-TV systems, which will receive the 3 inches. It is made of high -strength poly - As the consumer -electronics industry audio data via satellite. The service might carbonate and contains several high -volt- looks for "the next VCR" -that is, the also be made available to TVRO (big -dish) age electrodes. next product that will send consumers in and DBS (little -dish) satellite -TV system When it is set up in the road, it appears droves to their local electronics retailers owners. only as a small bump. However, the disc and restore life to the industry-some old Preliminary field testing is going on can be armed before the target vehicle products are showing renewed strength. now, and initial production units should be passes over it by the pursuing police of- Even though the household penetration of available by the end of this year. Although ficers or by other officers at the scene. TV sets is over 98%, sales are strong prices haven't been - determined yet, the When the target vehicle passes over it, the stronger than ever, in fact. In September of Listen Up audio system should cost less disk discharges high- energy electric last year, the last figures that were available than $500. Monthly service charges will charges, which disable engine controls, as we went to press, the TV industry had apply to basic audio programming. Pre- sensors, computers, and other circuits. its best month ever. For the first time, unit 20 mium programs will also be offered. The developers envision future versions sales of TV sets passed 3- million.

www.americanradiohistory.comAmericanRadioHistory.Com ELECTRONICS WISH LIST

Mini- Component Audio System The six -plus -one CD changer in the MS 7766 bookshelf stereo system from Sansui USA Inc. (1290 Wall Street West, Lyndhurst, NJ 07071) provides hours of uninterrupted music. The changer has an internal stacking design and features 24- track programmability. With the touch of a button, the user can choose one of 30 preset radio stations, thanks to the system's PLL digital tuner. The dual -well, auto -reverse cassette deck makes dubbing simple. A clock/sleep timer adds to the system's convenience. The 50- watts -per -channel system also offers sound -field control, Dynamic Bass Boost System, and a remote control. Price: $649.95.

Game Boy/Super NES Adapter Audio System The Super Game Boy accessory from Nintendo of America Inc. (4820 150th Sansui MiriComponent Avenue N.E., Redmond, WA 98052 -5111) allows video -game enthusiasts to play any of the more than 350 available Game Boy cartridges on the Super Nintendo Entertainment System (Super NES), displaying them in full color on the TV screen for the first time. The Super Game Boy is a Super NES cartridge that contains a Game Boy adaptor. When a Game Boy cartridge is inserted, it is transformed from a black- and -white game to a bright, multi- colored image on a big television screen, complete with stereophonic sound. Game action is displayed in varying shades of four colors that can be customized by the player. The player can also use one of several pre- stored, animated border designs or can create his or her own using a paint -type program. New titles specifically designed for the Super Game Boy will use the 256 -color palette of the Super NES. Price: $59.95.

Plain -Paper Fax The FX5500 is Samsung Electronics America's (105 Challenger Road. Ridgefield Park, NJ 07660 -0511) first entry into the plain -paper fax market. The fax uses LED printing technology, features a 256 -KB receiving memory, and offers a telephone answering- machine interface. It has a nine -second transmission NES Adar ter speed, a 20 -sheet automatic document feeder, and a printing speed of five pages Game Boy /Super per minute. The FX5500 can store 20 one -touch and 50 two -touch programmable numbers. Price: $1699.99.

Multiroom, Powered "Tube" Loudspeaker The Bang & Olufsen (1200 Business Center Drive, #100, Mount Prospect, IL 60056) Local Control System 9000 is a unique, two -in -one active loudspeaker that was specifically designed for multiroom applications. It can bring both sound and control of a centrally located audio system to different rooms. Right and left amplified speakers, a status display with clock, an independent volume control, and an infrared remote -control transceiver are all housed in a slender oval cabinet of polished aluminum, intended for horizontal placement. The black speaker grilles are divided by a field that contains an illuminated status display and two sets of sensi -touch controls for hands -on operation. A Beolink remote control also can be used to gain access to all available sound sources. The tube- shaped LCS it to 9000 measures 433/4 x 33/4 x 43/9 inches and comes with a bracket that allows be wall mounted. An optional stand is available for table -top or bookshelf placement. The LCD 9000 uses Bang & Olufsen's Adaptive Bass Linearization (ABL) technology to provide large speaker sound. It features two loudspeakers, each with its own amplifier. One, for the treble, drives a 3/4-inch tweeter; the other, for the bass, drives a 31/2-inch woofer. The close connection between the amplifier and loudspeaker is said to give improved signal control and provide extra power for Bang & OIusen LCS 9000 ?owered Loudspeaker a purer, more authentic sound. Price: $1395.

www.americanradiohistory.comAmericanRadioHistory.Com ELECTRONICS WISH LIST

Mini Handheld Cellular Phone Weighing just seven ounces and measuring a compact 5.25 x 2.1 x 0.9 inches, the Radio Shack (700 One Tandy Center, Fort Worth, TX 76102) CT-352 handheld cellular phone makes it easy to keep in touch while commuting, at a job site, on a business trip, or on a family outing. It will store up to 98 different names or numbers for quick dialing. To dial by name, you enter the first one or two characters of the name and the phone automatically locates the number. Incoming calls can be answered by pressing any key on the keypad. The phone can also be set to automatically answer without pressing any key. A menu system lets you quickly view and change the current setting of any phone function, including ring type, volume, light control, and auto -answer. Other features include a supertwist, backlit LCD; continuous battery- power -level and signal- strength indicators; touch -tone compatibility for special services such as banking by phone and voice mail; and scratch -pad memory for temporarily storing a name and number during a call. Price: N /A.

Adjustable Monitor Arm Designed to free up valuable desk space, the EasyVue Model 6130 adjustable monitor arm from MicroComputer Associates (Division of Rubbermaid Office Products Inc., 9920 La Cienega Blvd., Inglewood, CA 90308 -7032) lifts the Radio Shack Minl Cellular Phone monitor above the worksurface. To provide the most comfortable viewing angle, a notch -slide mechanism is used to adjust the height in one -inch increments, four, five, or six inches above the desktop. The monitor platform rotates, tilts, and swivels for enhanced viewing, and the base also rotates. The platform holds monitors weighing up to 40 pounds with foot separations up to 12 inches. The arm attaches to the desk with a metal clamp. Price: $49.95.

Fuzzy Logic Camcorder The VM -RZ2R 8mm camcorder from Sanyo (21350 Lassen Street, Chatsworth, CA 91311 -2329) offers fuzzy-logic control and preset shutter speeds for easier operation and better vidcomaking results. The high -speed (up to 'Ammo second) electronic shutter offers six presets identified in the viewfinder as sports, auto high -speed, low -light, flicker, close -up, and normal. Those settings eliminate guesswork and simplify shutter -speed selection. Sanyo's fuzzy -logic technology automatically adjusts the focusing, iris, and white balance by imitating the human Sanyo Fuzzy Logic 8mm Camcorder thinking processes. For instance, the automatic white balance corrects color for different lighting conditions by analyzing picture information from 64 separate image areas. Manual focusing is also possible. The VM -RZ2R also features an 8:1 power zoom lens, a flying erase head, a wireless remote control, I -lux low -light capability, and a built -in omnidirectional microphone. Price: $699.99.

Tiny Travel Clock/Radio According to Executive Travelwure (P. O. Box 59387, Chicago, IL 60659 -0387; Tel. 1 -8()0-397- 7477), its MicroPak is the world's smallest full - feature, AM /FM travel clock radio. Because of its ultra- compact size, it can be packed into the tightest space. The clock radio measures 41/2 x 21/2 x is/R. inches when closed. With the touch of a button, the MicroPak 's black clam -shell case pops open to reveal a large LCD time display, angled for easy reading. The power switch is located under the lid to prevent the power from being accidentally turned on while the radio is packed in a suitcase. The MicroPak provides a choice of music or beeper wake -up alarms. It features a telescoping whip antenna, a snooze 22 MlcroPak Mini Travel Clock Radio button, and an earphone jack. Price: $49.95.

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Breadboard analog and digital circuits the easy way with this versatile digital/analog trainer.

Breadboarding circuits is al- used as common tie points for dif- input signals of different frequencies ways difficult work. It requires ferent voltages. Everything is housed into a circuit. The XK -525 has a built -in lots of patience and extreme in a rugged plastic case. variable function generator that can concentration because it's very easy A power supply is essential in any generate sine, square, and triangle to misplace a lead or leave a con- circuit, and the XK -525 provides five waveforms from 1 hertz to 100 kilohertz nection out entirely. It makes sense, DC different voltage sources that can in 5 steps. The output is variable from then, that any device that makes satisfy almost any conceivable circuit 0- to 15 -volts peak -to -peak. The DC breadboarding circuits neater, sim- requirement. To begin with, there are offset can be adjusted ± 10 volts from pler, or less time -consuming is a good Iwo variable supplies, one positive the zero crossing. An AM input allows investment -as long as it's not an ex- and one negative. The positive varia- an external signal to amplitude mod- pensive one. In that light, one of the ble supply is adjustable from + 1.25- to ulate the function -generator output, best breadboarding investments that + 20-volts DC, and the negative vari- while an FM input allows an external I have found is the Model XK-525 Dig- able supply is adjustable from -1.25- signal to frequency modulate the ital/Analog Trainer from Elenco Elec- to - 20 -volts DC. The variable supplies function -generator output. tronics, Inc. The trainer is sold as a kit ± can output a full ampere at up to 15 The digital section of the XK -525 infor $149.95. ± volts and half an ampere at 20 volts. cludes 8 data switches that set out- Positive and negative, 12 -volt, fixed puts to high and low logic values ( +5 Features. The XK-525 makes short power supplies are also included, and 0 volts). The 8 outputs each have work of breadboarding circuits by both of which can output up to 1 am- 5 tie points, which can be used to set putting lots of what you need it to do pere. There's also a fixed + 5-volt, l- conditions on a data bus, as well as for right at your fingertips. Different power amp supply. All of the supplies are reg- other applications. supplies, a function generator, and a ulated and short -circuit protected. A Two logic switches are included, digital-logic section are all combined 30 -volt AC, center -tapped supply is both with normal and complimentary on one control panel, There's also also present. The trainer draws its own outputs. The logic switches are plenty of room for installing your own power from any convenient 117 -volt bounce -free. If you are unfamiliar with components: two large breadboards, AC outlet. that concept, the contacts of a reg- each with tie 830 points. In addition, A function generator is a valuable ular switch can "bounce," causing six separate power-bus lines that span accessory when designing or testing sensitive, high -speed digital logic in- 24 the width of the breadboards can be out a new circuit. It's a quick way to (Continued on page 94)

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www.americanradiohistory.comAmericanRadioHistory.Com THINK TANK

By John J. Yacono, Last month, we talked Say you pick up a resistor some readers' letters do fol- Technical Editor, about the various watt- and it has three bands on it: low: Windows Magazine ages that resistors come in yellow violet, and orange. and how to tell the wattage (Any bands of a color not MODEL -RAILROAD of a resistor by its ap- found in Table 1 deal with SOUNDER pearance. We'll continue tolerance, so we'll ignore The circuit that I have our discussion of resistors them for now.) Using Table 1, enclosed (see Fig. 2) can this month, and also get to we find that the bands indi- be used in model railroad- a few model- railroad -re- cate the digits 4, 7, and 3. ing to sound an electronic lated circuits sent in by diesel horn when the train some contributors. approaches TABLE a railroad As you'll recall, the 1- watt- crossing. I RESISTOR -BAND COLORS mounted the cir- Model - age of a resistor determines cuit in a 50 -foot HO -scale how Color Digit much heat it can dissi- box car, and placed the B- pate Black Railroad per second. Another 0 ohm speaker, S1, behind Brown even more important 1 the doors, which I now have Red 2 Circuits characteristic of a resistor is Orange 3 to keep open. A longer its resistance to current flow, Yellow 4 cattle car would be a bet- which is measured in ohms. Green 5 ter enclosure because it is Resistors rated above 5 Blue 6 larger and has holes for Violet 7 watts have their resistance sound to escape. Gray 8 values stamped on them in White 9 Reed switch S1, which I plain English. Lower-wat- cannibalized from a Radio tage resistors have three or Shack reed relay, was four (in the case of 1% The first two digits indicate mounted on the bottom of resistors) colored bands on significant numbers (47), but the car. When the "sourd the last digit (3) tells us how car" approaches the cross- 3 OR 4 BANDS INDICATE many zeroes follow the first ing, S1 is momentarily RESISTANCE digits. In that case three closed by a magnet that zeroes should follow the 4 must be installed under the and the 7. That gives us a track, thus starting the tim- value of 47,000 ohms. ing cycle and sounding the Let's take another exam- horn. EXTRA ple, this time with four Before you can use U2, BAND INDICATES resistance-indicating bands the ISD 1000A record and TOLERANCE of these colors found in playback (NOT FOUND IC (available at ON ALL Table 1: brown, red, green, Radio Shack and RESISTORS) red. The first three bands elsewhere), you must first Fig. 1. Colored bands are indicate significant figures, program it by breadboard- used on a resistor to indicate and from the table we can ing the circuit found in the its value in ohms and its see that brown /red /green applications data included tolerance. means 125. The last band, with the IC. To record sound which tells us how many on U2, you'll need a sample their bodies (see Fig. 1) that zeroes follow the numbers, of the sound that you want indicate the resistance val- is red. That tells us 2 that the IC to play. I called a ue. Most of the time, there is zeroes follow the number local railroad yard to make an extra band that indi- 125, so the resistor's value is an appointment to record cates the part's tolerance 12,500 ohms. the sound that I required. (which we'll explain next What if the last band is Another option is to stand time). Resistance- indicating black? That means that no near a railroad crossing bands can be one of ten zeroes follow the first digits. holding a microphone, colors; each color repre- For example, if the resistor waiting for a train. sents a digit, as shown in bands are white (9), brown During construction of the Table 1. (1), black (0), the resistor's playback circuit, save To see how the system value is simply 91 ohms, no space by using single -turn 28 works, let's take an example. zeroes follow. But right now trimmers for the variable re-

www.americanradiohistory.comAmericanRadioHistory.Com model railroad heard as plug is a nice, practical well as seen. touch. +5V 932 By the way, although I C2 -4' R1 100K CROSSING-GATE 100 have been an avid reader 10K " of Popular Electronics for FLASHER is S1 many years, I have no idea This circuit (see Fig. 3) U3 REED 555 what book everyone is talk- the solution for Bob Williams' SWITCH ing about in Think Tank. I concern in the October c would like to know what 1994 Think Tank. It works type of book you are send- great as a crossing -gate ing to people who have flasher. The circuit contains their articles published in only six parts, including the C5 two incandescent lamps, R3 the column. 10 1.2K -Brian Couchene, and is cheap and easy to A Escanaba, Ml build. However, you do R4 Normally, when some- need a filtered power sup- 10K one's letter appears here ply to run the circuit. N sent a Think Tank Il The Iwo lamps, 11 and 12, C6 1 they are 250 book which is a collection flash back and forth at a SPKR1 of circuits that have ap- rate of about 1 hertz. That 8,0 peared in the past. If a flash rate is determined by reader already has one, or the values of R2 and C1. +5V we are temporarily out of You can alter the value of stock they receive another R2 for faster rates, and C1 book from our library, for for slower rates. Hope that example a Circuit Circus helps you out. book. -Paul Vandermyde, By the way, I like your Morrison IL Fig. 2. This circuit can fit inside a model -train car and output circuit o lot. The recharging I like it when readers help any sound you record in the ISDI000A. Imagine a cattle car that moos! The professional weather sistors. To install U2, mount it plug to turn off the circuit. station for people curious on a low- profile socket. If There are unlimited ap- you have an O or larger - plications for the above about the weather. scale railroad, you could circuit in model railroading. use larger and louder In addition to providing a speakers, an LM380 IC am- horn for a train, it can be plifier for more power, and used to reproduce the another battery in parallel sound of a ringing bell by a for extended use because railroad crossing, or a po- of the extra space. lice or ambulance siren. The phone jack, J1, which However it is used, the cir- is mounted on the bottom cuit is sure to make a of the car, serves two purposes. It serves as a means Haven't you always wanted a weather station? of charging B1, the 9 -volt The Weather Monitor II makes a state -of- the -art NiCd battery, and also pro- +12V weather monitoring system affordable enough vides a way to turn the for home use! To the circuit off. charge R1 FEATURES INCLUDE: battery without disassem- 22K Inside & Inside Instant Metric Outside Temps Humidity Conversions the car, just wire a 9- bling Wind Speed Wind Chill Outside Hum. volt battery snap to a male R2 & Direction . Alarms & Dew Point 1MEG Option phone plug. Then just insert Barometer . Highs & Lows Optrfaional PC Time & Date the phone plug into the car Rainfall Option Interface and the battery snap into Order today: The your battery charger. 1 -800- 678 -3669 battery will last about 4 M -F 7 a.m. to 5:30 p.m. Pacific Time PE651E hours, depending on how Fig. 3. This simple circuit FAX 1 -510- 670 -0589 M/C and VISA One -year warranty 30 -day money-back guarantee many railroad crossings you can operate the incandescent have on your layout. When bulbs in a railroad- crossing DAVIS INSTRUMENTS not in use, insert the phone flasher. 3465 Diablo Ave,, Hayward, CA 64545 29 CIRCLE 162 ON FREE INFORMATION CARD

www.americanradiohistory.comAmericanRadioHistory.Com flash rate. Power comes sistor R1 reduces the current OI U2 p (TO from an extra set U1 if R4 is 7806 of outputs to set for mini- TRACK from the back of a train mum resistance. TRANSFORMER o OUTPUT) transformer via the 8 -volt Variable resistor R4 car voltage regulator. also be adjusted so that -Brian Rapp Buffalo, NY each individual car in a 8 4 The power- supply feature train will change the colors is R1* much appreciated. This is of LEDI, a bi -color unit, 01 one 2N3906 of the few projects back and forth indicating U1 R2 where the designer pro- train movement. That can 555 10K +y vided multiple parts values be handy if 2 circuits are C3 for a circuit. I would be very used, one at each end of R3 15 5 C4 ? 22052 R4 surprised if any of our read- the track block. It will indi- C2 15 220Q ers wouldn't have some cate that the train has .01 R5 R6 combination of junk -box begun to move. S1 100K 4 100K parts to make the circuit. Mount LEDI on the cor- LEDI LED2 trol panel. The circuit is REED SWITCH TRACK- CONTROL designed to indicate a 'SEE TABLE O SIGNAL green when no train is pres- A This circuit (see Fig. 5) is a ent. When a train covers variation of the track -con- PCI, U1 switches LEDI to TIME R1 trol signal circuit printed in red, indicating the train is in C1 = 101.1.F Cl e 10011F Think Tank in the October position. 100K 2 SEC. 16 SEC. 1994 issue. It is used to A 3 -lead, bicolor LED 220K SEC. 33 SEC. 3 indicate trains in hidden could have been used to 470K 6 SEC. 70 SEC. tracks, such as tunnels and conserve power, but that 1 MEG 15 SEC. 175 SEC. holding tracks, and does would have meant one B not require modifying the more wire running to the trains themselves. Fig. 4. Featuring a reed switch operated by train proximity, this control panel. circuit (A) has everything you need to activate an LED -based The circuit is based on a -Robert Hartle, Tionesta, crossing signal. To change the time period of Ul, use these 555 timer IC, U1, and oper- PA substitutions (B). ates on 5 -volts DC to make To change the values of it usable with digital logic. R2 and R3 to deal with 12 each other out. While you'll by C1 and R1. To alter that The operating power of the volts, double the values need a means to switch this time period, replace C1 circuit can be converted to shown in the schematic, circuit on and oft the reed - and R1 with components of 12 volts by increasing the then jump to the next -high- switch technique used in the values in the provided values of R2 and R3. est standard value. For Fig. 2 should give you some table (see Fig. 4B). The out- Train detection is accom- crowded control panels r ideas. By the way, because put of pin 3 is connected plished by photocell PCI, recommend using ribbon the 555 must source current directly to the flash circuit, which should be mounted cable to improve neatness. part of the time, I recom- which is a free -running mul- between the rails, flush with Start by hooking up the mend using a 555TLC, the tivibrator (in this case a flip - or slightly below the ties. A indicator furthest from the CMOS version of the 555. flop that triggers itself). small light must be cable inlet with two adja- The output from the lamps Resistors R3 and R4 limit mounted directly above cent conductors, then peel will be more even then. current to the LED's (which PCI when used in any dark back the rest of the cable flash alternately). If desired, area. Resistor R4 is adjusted to the position of the next FLASHER REVISITED changing the values of C3 so that when a train covers indicator, and trim. Connect I am responding to your and C4 will change the PCI the circuit triggers. Re- that indicator and proceed column in the October 94 in the above manner until a

issue I about hobby circuits. whole row of indicators is used a similar circuit (see wired; then, run the cable Fig. 4A) in a crossing signal. out the panel. Also, take It is a pretty- common timer advantage of using com- circuit, based on a 555 mon wiring, (+ V or ground) timer IC (U1). 5VDC whenever possible. The monostable timer, U1, Well, ifs time to close. Till is triggered by a reed next time, please send in switch via a small magnet your creations and sugges- under the engine. When tions to me here at Think that happens, the output at Tank, Popular Electronics, pin 3 of U1 remains high for Fig. 5. Want a full -blown railroad -control panel? Try using 500 -B Bi- County Blvd., Farm- 30 a time period determined multiple copies of this circuit to keep track of train positions. ingdale, NY 11735.

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www.americanradiohistory.comAmericanRadioHistory.Com BY RODRICK SEELY

With this headphone guitar amplifier you can practice your guitar playing and prepare for a rock n' roll career, all without waking up the neighbors. BUILD A HEADPHONE AMPLIFIER FOR YOUR GUITAR

Any electric -guitar player songs. That input can also be used driven to produce a soft distortion knows about the high cost of with a keyboard or drum machine. effect. To prevent any unwanted DC musical equipment. To pur- The Jam Pak works with any stereo "swishing" noise, a coupling capaci- chase a small practice amp, one or headphones and will operate for tor, C8, is used. two effects pedals, associated patch hours from a single 9 -volt battery. Switch S1 toggles between the cords, and batteries and other clean and distorted signals. When S1 is power -supplies can cost at least a Circuit Description. Figure 1 is a on the CRUNCH setting, diodes D1 and few hundred dollars. Not only is that schematic diagram of the Jam Pak. D2, and U1 -d produce a distortion equipment bulky and expensive, but The main components in the circuit effect by clipping the amplified signal to make things worse for the budding are two LM324 quad op -amp IC's (U1 at 0.7 volts. Frequencies below 160 Hz musician, there's always someone and U2) and two LM386 power -amp are attenuated by R5 and C6. The who doesn't appreciate a killer over- IC's (U3 and U4). The inputs to U1 and amount of gain or "fuzz" is controlled drive sound rattling the windows! U2 are biased to a little less than half by R7 and potentiometer R6, and re- It's not easy becoming a rock 'n' roll the power-supply voltage by resistors sistor R8 adjusts the distortion level to superstar. However, with the Jam Pak R10 and R11. Capacitors C1 and C2 match the tone- control level. headphone guitar amplifier de- filter the power -supply and bias volt- One of the reasons that the Jam scribed in this article, you will find it ages. Pak sounds great through a pair of easier to practice. Simply plug in your There is no power switch in the cir- headphones is its unique stereo - "ax," put on the headphones, and cuit, Input -jack J1 turns on the Jam Pak imaging effect. That is produced by a crank it up as loud as you like. You can when the input plug is inserted. When phase -shift circuit, composed of U2 -a jam anytime, anywhere, without dis- an audio signal from an instrument is through U2 -d, R20 -R23, and C9 -C12. turbing your family or neighbors. Sim- input through J1, the signal is fed Each stage shifts 90 degrees at the ilar headphone amplifiers available through coupling-capacitor C3 to the same frequency. The frequency of the through music stores typically cost tone -control circuit composed of U1- shift at U2 -a is: a hundred dollars, but you c, R2, R4, and C4. Frequencies above around f = 1 /(2aRC) can build the Jam Pak for under $50! 1 kHz are amplified or attenuated de- is in hertz, n is The Jam Pak is a personal -head- pending on the position of potenti- where f the frequency phone guitar amplifier featuring a ometer R4, which is the tone control. equal to 3.14159, R is the value of R20, unique stereo -imaging effect, and Resistor R2 and capacitor C4 filter un- and C is the value of C9. For the fre- adjustable distortion, overdrive, and wanted high frequencies. quency of the shift at U2- b-U2 -d, use C10 tone controls. It also has an auxiliary Audio level and overdrive are con- the values of R21 -R23 and -C12, input that allows you to plug in any trolled by potentiometer R9; with that respectively (as Fig. 1 shows, those val- walkman-style tape- or CD- player level- control adjusted to full volume, ues are all equal). The four stages pro- and play along with your favorite the circuit's final amplifiers are over- vide 360 degrees of phase -shift at 330 33

www.americanradiohistory.comAmericanRadioHistory.Com 1i+ O+V J1 B1 + GUITAR 9V C1 CLEAN O -. S1 INPUT T 100 o CRUNCH 1 C8 .1 C3 .1 R8 +V 47K R9 12 10K R12 R13 R14 R15 R16 R17 R18 R19 22K 22K 22K 22K 22K 22K R10 R1 LEVEL 22K 22K 100K 1MEG 3 1/4LM324 C9 In .022 R6 C7 ^ VH R4 500K .001 FUZZ 100K R3 C5 R5 +V TONE 1K .01 4.7K R7 470K

D1 D2 1N4148 C 1N4148 R20 R21

22K 22K 32KR22 R2322K

R11 + C2 82K 100 R28 10K R29 R33 10K 10K C13 R26 .1 47K o K -AlA R35 R31 R32 t 10K J3 J2 10K +V 10K .` AUXILIARY -4iM (TO STEREO HEADPHONES) INPUT C14K Rn .1 47K C15 4 R24 1 U1- 1 330 +I( +V R25 AM 1 /4LM324 C18 3352 R30 11 R34 220 10K 10K C20 +K C16 C19 .01 LM386N-1 220 .01

Fig. 1. From the hard distortion provided by Ul -d and DI and D2 to the stereo imaging accomplished by U2, the Jam Pak is a guitarist's dream come true. Note that there is no power switch in the circuit, as JI turns on the unit whenever an instrument cable rs plugged in.

Hz, which is about the center of the and difference amplifiers through R26 in Figs. 2 and 3 or purchased from the frequency range for guitars. At fre- and R27. Capacitors C15 and C17 source listed in the Parts List, There are quencies above and below 330 Hz, provide AC- coupling of the sum and a couple of good reasons why a PC- various degrees of phase shift occur. difference signals to U3 and U4, the board is recommended for the proj- That phase -shifted signal is summed final amplifiers. ect. One reason is to prevent the noise with the original signal for one chan- Both U3 and U4 have a fixed gain of and self -oscillation problems that can nel (U1 -a), and subtracted from the 20. With a supply voltage of 9 volts, occur in audio projects using other original signal for the other channel they produce a power output of construction techniques. Also, using a (U1 -b). The result of all that is an inter- about 1/2 a watt into 8 -ohm head- PC -board simplifies construction and esting panning effect that is frequen- phones. Capacitors C16 and C18 makes the finished product look neat cy dependent. high -pass filter and couple the output and compact. To play along with prerecorded to headphone -jack J3. Now, let's turn Most of the components listed in music, or a keyboard or drum ma- to building the amplifier. the Parts List are inexpensive and chine, you can feed the stereo signals readily available from hobbyist from those sources into auxiliary -jack Construction. The Jam Pak pro- sources and catalog distributors. Any J2. Those signals are attenuated by totype was built on a double -sided enclosure of a suitable size can be R24 and R25, AC- coupled through printed- circuit board, which can be used for housing the circuit board, 34 C13 and C14, and mixed into the sum etched from the templates provided jacks, and panel components. A pre-

www.americanradiohistory.comAmericanRadioHistory.Com drilled enclosure with battery corn - partment, belt clip, and two-color silk - =i is available from the kit sup- o ! o screening plier. Use the parts -placement diagram o in Fig. 4 as a guide when building the Jam Pak, but keep the following in IL r-0-\;:vb- mind: To keep the circuit board small, most of the resistors are installed close together and standing up. To prevent a short, make sure that those part leads are not touching. Double - check your placement of integrated - circuits U1 -U4 and the six electrolytic C2, and C15 -C18) to .agi T°1 capacitors (C1, make sure their polarities are correct. Fig. 2. Use this template to etch the component side of the printed- circuit board. The Also check to see if diodes D1 and D2 pattern is shown here in its full size of 23/8 x 3 inches. are installed with their banded ends facing in the directions indicated by : =I the parts -placement diagram. _-o Install the IC's, jacks, capacitors, - resistors on the component and fixed of the PC board. The switch and ..ó side 00 ¡ the potentiometers should be o mounted on the solder side of the circuit board (using PC -mount potenti- 88 .... :: ometers eliminates the need for messy wiring, but panel- mounted units could be substituted if absolutely necessary). Make sure to solder on both sides of the circuit board wherever necessary. After you have installed all the circuit-board components, solder the 9 -volt- battery snap in place, making sure that the polarity Fig. 3. This is the template for the solder side of the PC board. Like Fig. 2, it is also the snap's leads is correct. shown full size. of

PARTS LIST FOR THE JAM PAK HEADPHONE GUITAR AMPLIFIER SEMICONDUCTORS R28R35-10,000-ohm Printed- circuit materials, enclosure, Ul, U2- LM324A quad operational knobs, stereo headphones, 9 -volt- amplifier, integrated circuit CAPACITORS battery snap with leads, wire, U3, U4- LM386N -1 low -power CI, C2- 100 -4 10 -WVDC, solder, hardware, etc. amplifier, integrated circuit electrolytic Note: The following items are D1, D2- 1N4148, small -signal diode C3, C6, C8, C13, C14 0.1 -µF, ceramic -disc available from Lynn Eren RESISTORS C4, C7- 0.001 -p,F, ceramic -disc Electronics (17093 S.W. Lynnly (All fixed resistors are %a -watt, 5% C5, C19, C20-0.01 -4 ceramic - Way, Sherwood, OR 97140; Tel. units) disc 503- 625- 2205): a complete kit of R1- 1- megohm C9 C12- 0.022 -p,F, ceramic -disc parts including an etched, drilled R2, R8, R26, R27- 47,000 -ohm C15, C17-1 -µF, 35 -WVDC, and plated -through PC -board with R3 -1000 -ohm electrolytic solder mask, and a pre- drilled R4- 100,000 -ohm, linear -taper C16, C18- 220 -µF, 10 -WVDC, enclosure with belt clip and two - potentiometer miniature electrolytic color silk -screening, $49; a fully R5-4700 -ohm assembled and tested unit, $59; the R6- 500,000 -ohm, linear -taper ADDITIONAL PARTS AND PC -board only, $15; stereo potentiometer MATERIALS headphones only, $10; a 72 -inch R7- 470,000 -ohm JI -'/ -inch stereo phone jack, auxiliary-input cable (3.5 mm R9- 10,000 -ohm, linear -taper circuit -board mount stereo plug to 3.5 mm stereo plug), potentiometer J2, J3 -3.5 mm stereo phone jack, $5. Please add 5% shipping and R10- 100,000 -ohm circuit -board mount handling. Check or money order, R11- 82,000 -ohm Sl -SPDT, micro- miniature toggle VISA and MasterCard are R12 R23- 22,000 -ohm switch accepted. battery R24, R25 -33 -ohm B1 -9 -volt alkaline 35

www.americanradiohistory.comAmericanRadioHistory.Com Checkout and Use. When the placement of all components has been thoroughly checked, you are ready to try out the Jam Pak, Plug a guitar, bass, or other unamplified musical instrument into input -jack J1, and -C14- R25 plug stereo headphones into head- -C13- --R24- phone -jack J3. Note, however, that the sound heard through the headphones might be surprisingly loud, so it is a good idea notto put them on just yet. 1 ¡ Connect a fresh, 9 -volt alkaline battery to the unit. With switch S1 in the R4 "clean" position and level- R9 I control I C5 R3 I set at low to moderate volume, the t. J C19 amplifier should sound undistorted. Adjusting potentiometer R9 to a high volume setting should overdrive the amplifier and produce a soft dis-or- tion effect. Level controls on the guitar or other instrument might need to be turned up to achieve the overdrive effect. With switch S1 in the R23 R22 U3 "crunch" position, the amplifier should produce a R19 C12 C11 R31 R28 R30 R34 R35 hard distortion or fuzz sound, which I I I I can be adjusted using the "fuzz" con- C7 r -I trol, R6. The tone control, R4, should Ci2 R7 1 I I I adjust the treble of both the "clean" I R6 I R14 and "crunch" sounds. I I I RIO' I I Playing scales is a good way to hear L J how the Jam Pak amplifier's stereo R12 effect works. As the frequency R21 changes, the position or panning of B1 the stereo channels also changes. + The stereo effect will sound the fullest Fig. 4. Be sure to double -check the placement and polarity of your components with when playing chords or fast riffs with a this diagram to avoid damaging any of them. Note that switch SI and potentiometers wide frequency range. R4, R6, and R9 mount on the solder side of the board. To use the auxiliary input, connect any stereo walkman -type cassette- or CD- player, drum machine, or other amplified audio equipment to jack J2. That input has a low impedance, which is appropriate only for devices intended to drive headphones or speakers. Other high -impedance sources might be damaged if connected to J2. The unit will operate for several hours on a good alkaline battery. Be- cause the power switch is part of JI, it is a good idea to disconnect the plug from the input when the amplifier is not in use. Once you get the Jam Pak working, you'll be able to practice any time of day or night you please, without irritat- ing those around you. And who knows, with a bit of practice and some luck, This compact amplifier lets guitar plu mush Up nu thcit- u-ith ut annoying rock n' roll stardom could be just 36 others. around the corner!

www.americanradiohistory.comAmericanRadioHistory.Com the operation of a Glowing gas -discharge tubes work. A typical circuit using a VR -ube As you can see, VR tube is simple: However, for this were among the first elec- is shown in F g. 1. As long as the cu-rent be using it to regu- tronic wonders. In the past, through the tube is kept within the project we womt -.Ne just want to make they were used as voltage regulators manufacturer's ratings (typically 5 to late voltages. the tube glow! in tube circuits. However, even though 40 mA), the voltage at E2 wi,l change gas- discharge tubes are still one of very little, despite variations in supply - Figure 2 shows the cir- the easiest ways to regulate voltages voltage E, or in the load curent. The Circuit. the (love' Nightlight. Its higher than 75 volts, they are rarely The above circuit only has one, re- cuit of c transformerless, half -wave applied to that task anymore. sistor, R1. To find the value of that re- basically supoly hat puts out enough What's a good use for a glowing sistor in ohms, use: power voltace to keep VI. the 0A3NR75 VR tube? Well, because it is a source of R1 = (E1 - E2) /lme, tube, glowing.l3ecause the circuit has faint light, a voltcge- regulating gas - tube cur- no trcnsfarmer, it's absolutely neces- discharge tube makes a great night - where Imax is the maximum for safety tact all conductors be light. With just one of -he tubes (which rent. sary osed n insulcted material! you can pick up on tie antique -tube enc of component failure, market for a buck or two), a couple of BY LARRY LISLE, K9KZT In the event fuse F1 will blow and interrupt the cur- mirrors, and a few other components, Resistor R1 limits the current you can build the Novel Nightlight, a rent flow. ode, D', which rectifies the truly unique prcject for the elec- Build this unusual nightlight through d smoothes out the tronics- oriented household. AC; oapccitor C' in an evening or two, u sing pulsa-ions The function of resistor R2 isn't immediately obvious but it is im- Voltage -Regulator Tubes. Voltage - old, gas- filled voltage- an If R2 wasn't in the circuit, un- regulator (VR) tubes are diodes; they porant. the rightlight would cause have a plate and a cold cathode (i.e. regulator tube. plugging n Cl to discharge one without a filament). During the the voltage thrcugh 13 and V1. However, when manufacture of a VR tube, air is re- below 75 volts, moved from the tube and the glass the voltage ctopoed VI would go at and the 75 volts in the envelope is filled with small quantities :wou d justsitthere waiting to zap of helium, neon, argon, or other gases Build a tube Even with a "bleeder" re- at very low pressure. When enough someone sistor like R2, ils always a good idea to voltage is placed between the plate capacitors with and the cathode, the tube glows. short power- supoly 'an insulated s. ewdriver after unplug- Let's take a look at how the tubes Novel Nightlight

www.americanradiohistory.comAmericanRadioHistory.Com Fig. 1. This is the basic circuit for using a gas -discharge tube as a voltage regulator. In the nightlight project, however, we just want to make the tube glow!

v1 0A3NR75 Fig. 2. The circuit for the Novel Nightlight is basically a transformerless, half-wave power supply that provides enough DC to light up VI, the voltage - regulator tube.

PARTS LIST FOR THE NOVEL NIGHTLIGHT D1- 1N5408 silicon rectifier diode

R1 -100 -ohm, 1 -watt resistor R2- 47,000 -ohm, 2 -watt resistor R3 -2000 -ohm, 5 -watt resistor C1- 20 -µF, 250 -WVDC, electrolytic capacitor V1-0A3 /VR75 voltage -regulator tube F1 -1/4-amp, fast -acting fuse 73/4 -inch square baseboard, 7 -inch square pieces of glass (2), 7 -inch square pieces of mirror (2), 7%4- inch square piece of glass, rubber mounting feet (4), molding strips Fig. 3. Here is an exploded view of the nightlight -case assembly. The molding strips (8), power cord and plug, octal hold the pieces of glass and the mirrors together once they are glued. Note the 45° relay socket for tube (Potter & angles on the top molding which allow for a tight fit. Brumfield 27E122 or equiv.), Fahnestock clips, fuse holder, sure to tie a knot in the epoxy glue, wire, solder, etc. cord before Because of the high voltages pres- inserting it, as that prevents strain on ent in the nightlight and the fact that the wiring. To keep the unit from wob- the tube will get hot, once you have ging the circuit and before touching bling, attach four rubber feet on the the circuit working, you should place it anything. bottom of the baseboard. in some kind of enclosure or cover. An There are a few ways to adjust the inverted food -preserving jar, an old Construction. The method of wiring brightness of the Novel Nightlight. First aquarium, or a Plexiglas enclosure used to build the nightlight isn't crit- of all, you can change the value of R3. can be used. In the author's pro- ical, For the prototype, Fahnestock However, keep in mind that the cur- totype, the enclosure was built as a 7- clips and some of the unused tube - rent shouldn't exceed 40 mA (with the inch -on -a -side glass and mirror box socket terminals were used to make values shown in Fig. 2, it's about 31 mA). (see Fig. 3). Two of the sides we'e connections. If you do the same, be Also, other voltage -regulator tubes made of mirror squares, so that when aware that pins 7 and 3 of the 0A3/ can be used instead, even though the the unit is assembled and viewed at VR75 are connected internally. 0A3/VR75 was the brightest of the sev- an angle, it looks as if there are four The circuit should be mounted on a eral that I tried. For a little variety, you glowing tubes. wood baseboard. In the prototype, could also add flashing neon bulbs To duplicate the enclosure shown in that 73/4 measures x 73/4 inches. Drill a with a capacitor and resistor for each, Fig. 3, you will need two glass squares hole in one corner the of board for the or an old mercury -vapor rectifier such and two mirror squares, measuring 7 power cord to go through, but make as an 866. (Continued on page 96)

www.americanradiohistory.comAmericanRadioHistory.Com Getting Started in Surface Mount Technology

Two projects that will get you started in building with surface -mount components.

BY RONALD A. REIS

project - For most electronics hobbyists, semblies are SMC's. So, if you don't ner the widest possible SMT the idea of hand -assembling want to let a whole component - building experience, using readily surface -mount components packaging revolution pass you by, available, low -cost surface -mount components. Each project is built on a ( SMC's) into a working project seems learn to build the electronic projects is intend- ludicrous. After all, as most of us know, of the near future, now. 1- x 13/4 -inch PC board that of a 9 -volt surface -mount technology (SMT) was ed to be taped to the side developed with automatic assembly SMT Project Building. To get you battery, its power source. The 9 -volt- in projects, in mind. Finding, grasping, arranging, started in building tomorrow's elec- battery snap found both and somehow soldering those tiny, tronic projects today, here are two fun, and the 8 -ohm speaker in the Tone non -SMT compo- leadless SMT components by hand is attention -getting, and, most impor- Burst are the only ridiculous. Right? Wrong delightfully tant, easy -to -build SMT projects: the nents used. wrong! Not only is it possible, but it can 555 Dual -LED Flasher and the Tone proj- be accomplished easily, quickly, and, Burst. Furthermore, to give you prac- Circuit Descriptions. The first Flasher, alter- for the most part, with tools and mate- tice in fabricating SMT PC boards and ect, the 555 Dual -LED surface - rials you now have on your work- soldering SMC's in place, a printed - nately flashes a pair of tiny, bench. circuit template for an SMT Practice mount LED's at a rate of approximately 1 the schematic As mentioned in the article "A Hob- Board is also included. 1 Hz. Figure contains byists Guide to Surface -Mount Tech- Both of the SMT projects presented for that project. nology" (Popular Electronics, Janu- here were chosen to give the begin- The 555 timer, U1, is configured as (oscillator), ary 1995), SMT is a packaging an astable multivibrator revolution that attaches tiny, essen- the frequency of which is determined resistors R1 and R2 tially " leadless" components to pads by the values of from on the surface of a printed- circuit and capacitor Cl. As Cl charges 1/3 2/3 voltage through R1 board (hence the name, "surface - to the supply pin 3, is high. As a mount technology"). That contrasts and R2, UI's output, is positive, with traditional "insertion -mount tech- result, LED2 is on (its anode while LEDI is off nology" (IMT), which uses compo- its cathode, negative) are nents with leads that are inserted (both its anode and cathode from 3/3 through the PC board. positive). When Cl discharges 1/3 voltage through R2, As you are about to discover, proj- to the supply pin low. As a result, LEDI turns ect- building with SMT is fascinating, 3 goes its is negative and its fun, and, increasingly, inevitable. Even on (now cathode turns off though today, for the most part, you anode is positive) and LED2 (both its anode and cathode are still have a choice between tradi- Fig. I. Here is the schematic for the 555 negative). The duty cycle for the cir- tional IMC's (insertion -mount compo- Dual -LED Flasher. The circuit is 50 percent; therefore, nents) and SMC's, tomorrow you might alternately flashes LEDI and LED2, two cuit nearly to an equal not; already, 50% of all the compo- surface-mount LED's, at a rate of each LED is on for close 39 nents in commercial electronic as- approximately 1 Hz. duration.

www.americanradiohistory.comAmericanRadioHistory.Com the artwork negative on top, to ultra- with a magnifying glass. However, hat violet light. might not be enough to locate any 5. Let the image develop. possible trace breaks, so you should 6. Rinse and drip -dry the board. check each trace (and pad) with a 7. Immerse the board in acid (ferric continuity checker (ohmmeter). That chloride is often used). way you can be sure that the board is 8. When etching is complete, thor- ready for the installation of surface - oughly wash the board and then dry it mount components. with a paper towel. Figure 5 is the template for an SMT 9. Remove the remaining photoresist practice board. By fabricating hat layer by lightly rubbing the board with board, you can gain experience in steel wool. etching SMT PC boards with small 10. Drill all necessary holes in the PC pads and thin traces. Also, you can board. In an SMT PC board, only use the practice board to rehearse mounting holes might be required. the SMC assembly techniques dis- The PC -board template for the 555 cussed later. For those reasons, etch- Dual -LED Flasher is shown in Fig. 3 and ing the practice board before the one for the Tone Burst is shown in tackling either of the two SMT project Fig. 4. Note the small component boards is recommended. pads and the extremely thin Fig. 2. The Tone Burst circuit puts out a traces - in some cases, a mere 0.015- inches Tools 500 -Hz tone, at a rate of 1 Hz, through and Materials. In building ei- an 8 -ohm speaker, SPKR1. Besides the wide. When fabricating those and ther of the two projects presented 9 -volt battery and its connecting snap, other SMT boards, two cautions are here, you will need the right tools and SPKR1 is the only non -surface -mount worth observing: materials. A full explanation of the component in the circuit. First, because you are dealing with items required was presented in "A Hobbyists Guide to Surface -Mount The Tone Burst puts out a 500 -Hz Technology" in the January 1995 issue tone 1 at a rate of Hz. At the heart of of Popular Electronics. If you have a the circuit is U1, a 556 IC, which is just x copy of that article, you might want to two 555 IC's in one 14 -pin package á o W V) i look it over. (see Fig. 2). Both "555's" are configured o J LLJ Briefly, here are some tools you'll as astable multivibrators. The first, or need: a soldering iron, a tweezers, a low- frequency, oscillator, using re- vise, and a magnifying glass. The sol- sistors R1 R2 and and capacitor C1, Fig. 3. This template for the 555 Dual - dering iron needs to be from 25 to 40 turns on the second, or high- frequen- LED Flasher's PC board is shown in its watts and should have a tinned tip cy, oscillator at a 1 -Hz rate. The latter is actual size of only 1 x 13/4 inches! Note with a conical shape, 1Áo of an inch or the small pads and extremely thin traces. alternately on and off for half a sec- less in diameter. The tweezers should ond. When it is on, it generates a 500 - have forceps -style tips. A small vise is Hz signal, that value being deter- ideal for securing the PC board while mined by resistors R3 and R4 and ca- components are being attached. Be- pacitor C2. That signal is amplified by _ cause SMC's are so tiny, no matter NPN transistor 91, which drives the 8- zW i ohm speaker. D

MN .f1'ß SIN :711MP M. SMT PC -Board Fabrication. The "L O N IIIM WM steps in fabricating an SMT printed - Fig. 4. The printed- circuit template for circuit board are identical to those the Tone Burst is also shown here full used in etching a traditional, single - size. sided, IMT PC board. There are, however, two additional steps, or cautions, traces not much thicker than a line that should be observed when SMT drawn with a pencil, it is a good idea boards are etched. We'll look at both to check the etching process fre- in a moment, but first, here are the ten quently. Pull the board out of the acid steps required to produce either an bath often and examine it closely for IMT or SMT PC board: acid undercuts. The narrow traces of 1. Clean the blank board with fine an SMT board are delicate- leaving steel wool to get rid of contaminants your board in the acid any longer and oily residue. than necessary to etch away un- Fa- 1 5/8 INCH 2. Spray a liquid photoresist onto the wanted copper might damage the Fig. 5. Fabricating this SMT practice copper -clad board. traces. board will give you practice in etching 3. Dry the photoresist with a hair dryer. Second, once the board is com- an SMT PC Board, and in mounting 40 4. Expose the sensitized board, with plete, check the PC -board pattern SMC's. It is shown here full size.

www.americanradiohistory.comAmericanRadioHistory.Com the board surface (see Fig. 6). Remove just outlined seem a bit intimidating, the iron, allow the solder to cool you might want to practice a little again, and release the tweezers. With SMC- placement first. That's where the the component "held" in place, SMT practice board, mentioned ear- you're ready to solder the other termi- lier, comes in. If you have etched the now nal in a traditional manner. board, as suggested, you can surplus SMC's. To solder gull -wing leads on three - proceed to "stuff it" with and four -lead components, proceed As you will notice, pads to accommo- as above. Tag solder one lead and date various sized two- and three -ter- then solder the remaining leads in the minal SMC's, as well as thin- and wide - conventional way (see Fig. 7). bodied DIP SOIC's, are provided. When soldering DIP gull -wing sur- Before actual component- place- Fig. 6. To tag solder a two- terminal face -mount IC's (SOIC's), first create a ment and assembly begins, clean SMC in place, create a pool of solder on of solder on a corner pad in your PC -board traces and pads with a pad, place the component above it, pool Then steel wool. Next, mount the PC board and reheat the solder so the SMC can preparation for tag soldering, securely in a vise. If you don't have a "sink" close to the board surface. pick up the IC with a tweezers and vise, you can try holding the PC board down by taping its corners to a flat how good your eyesight is, you'll want SOLDERING IRON TIP surface with masking tape, a magnifying glass close by. A desk- If are using a desk-top magni- top illuminated magnifier, the kind you fier, swing it into place and turn on the that sells for around $80, is ideal. At the light. Place the rest of your tools, mate- very least, get yourself an inexpensive rials, and components nearby, within hand -held lens. easy reach, and get comfortable. The materials you'll require are sol- Pretend you're a surgeon about to der, liquid flux, a drop dispenser, a de- perform a delicate operation. Then, fluxer, and solder wick. The solder pick out a component location on should have a 63/37 tin -lead mixture, just the PC board, take a deep breath, and should be no greater than 0.020 exhale, and give it a go. You'll be a pro inches in diameter. If you can find it, a at SMT hand assembly in no time. Now, 0.015- inch -diameter solder is even let's build our projects! better. When purchasing a bottle of it is of the noncor- liquid flux, be sure 7. To solder gull -wing leads to a Fig. Construction. The parts -placement rosive type. To directly apply the flux PC board, use a 63/37 tin -lead solder diagram for the 555 Dual -LED Flasher where it is needed, you will want a that is 0.015 inches in diameter, and a is in Fig. 8, and the parts- place- drop dispenser. Also purchase a light - conical soldering -iron tip that is 06 of shown ment for the Tone Burst is given in Fig. duty defluxer, in a spray can, which will an inch or less in diameter. 9. Whichever project you build, begin be used to clean your assembled PC the integrated circuit. board of all contaminants. Finally, place it onto the copper pads, mak- by attaching in projects the IC is when choosing solder wick, select a ing sure to center the IC right -to-left as Note that both so that pin 1 is on the top -left width of 0.030 inches. well as top -to- bottom. While holding placed the chip in place, apply the soldering pad. Next, install any polarized ca- positive terminal is indi- Attaching SMC's to PCB's. In build- iron tip to the pre -tinned pad. Keep pacitors (the to cated by either a colored bar or a ing an SMT project, we suggest that the iron in place just long enough you use the tag solder method dis- flow the solder. If necessary, pivot the cussed in the aforementioned article. IC about the soldered pin to again align all pins with their respective Here is a review of the procedures for -R2 tag soldering various SMC's to a sur- pads. I hi lî, face mount PC board: To ensure the IC doesn't pivot, sol- to the To tag solder a two- terminal SMC to der a second pin "kitty- corner" forget to the surface of your PC board, first, first. When doing so, don't 1 using your drop dispenser, apply a apply a small amount of liquid flux. dab of liquid flux to one PC -board When the chip is secure, "bathe" one ¡ B1 l.ED1 pad. Then, using your soldering iron line of pins with liquid flux and solder and solder, create a small pool of sol- each pin, moving quickly to avoid T der on that pad. Allow the solder to overheating the IC. Then repeat the row of solidify. above step with the opposite Next, with the SMC held in your pins. Finally, inspect your work under Fig. 8. Use this diagram as a guide tweezers, rest the component on its the magnifying glass, looking in par- when building the 555 Dual -LED PC -board pads and hold it in place. ticular for solder bridges. Flasher. Because their markings are so to Then, using a soldering iron held in At this point, you could continue di- small, polarized SMC's can be hard when aligning your other hand, reflow the solder so rectly to the assembly of your chosen work with, so be careful 41 that the component "sinks" close to project. However, if the procedures them.

www.americanradiohistory.comAmericanRadioHistory.Com small marking). Proceed to install any "abuse," this is the time to find out. If -R1- -R3- non -polarized capacitors. your assembly techniques were good, R2 You can then place all the resistors. the SMC's will hold.

B1 Because those components have no Finally, attach a 9 -volt battery. Your U1 R4 polarity, they can be installed in I+ either project should blink or beep, depend- Cl direction. Do, however, solder them in ing on which one you built. If the oroj-

I -c2- place so that their resistance value is ect fails to function correctly, make -R5- visible (for an explanation of how the sure that you are using a fresh 9 -volt SPKR1 values are read, once again refer to battery. Then, check component Qi 4 the previously mentioned article). placement and solder -joint integrity, The 555 Dual -LED Flasher uses two and examine the project under your LED's that are, of course, polarized. The magnifier. cathode end is usually marked with a When your project is working, at- dot of green or red paint. If you're tach it to the battery with double - Fig. 9. This Tone Burst parts -placement building the project, attach the LED's sided tape. For the Tone Burst, if you diagram should make building the at this time. used a small enough speaker, you project a lot easier. Double check your The Tone Burst Project includes a can affix the unit by taping it to the battery- and speaker -wire connections to three -terminal transistor. Because that opposite side of the battery. make sure they are correct. tiny component can be placed on How to Get SMC's. You can par- PARTS LIST FOR THE chase surface -mount componerts in 555 DUAL-LED FLASHER single -lot (or "near- single -lot') quantities from a growing number of elec- U1 -555 timer, surface -mount tronics distributors and retail ou *lets. integrated circuit First, check with your local electronics LED1, LED2-Green LED, surface store. Second, look at the list of dis- mount tributors presented in the aforemen- R1-1000 -ohm resistor, surface tioned SMT article. mount One of those sources, the Elec- R2- 100,000 -ohm resistor, surface tronics mount Goldmine (PO. Box 5408, Scot- R3, R4-470 -ohm resistor, surface tsdale, AZ 85261; Tel. 602 -451 -7454), mount has exactly what you need for either CI- 10-11F, 10-volt, electrolytic of the above two projects. In some capacitor, surface mount cases you will have to purchase com- BI -9 -volt alkaline battery Surface -mount components are much ponents in lots of anywhere from 5 to Printed-circuit materials, 9 -volt- smaller and lighter than their insertion - 20. That's practical, however, because battery snap with leads, wire, mount- component cousins. you'll probably want to use the extras solder, hardware, etc. for solder practice or for building the PC board in only one correct di- more projects. PARTS LIST FOR THE rection, you can't get its placement TONE BURST wrong. If you are building the Tone Conclusion. Having built one or both Burst, install the transistor now. of the SMT projects presented in this U1 -556 dual timer, surface -mount Tag solder the battery -snap wires article, you have integrated circuit entered an entirely directly to the appropriate PC Ql- 2N2222 transistor or equivalent, board - new realm of project building. In surface mount pads. Be sure to observe correct po- doing so, you have taken a leap rot R1 -2200 -ohm resistor, surface larity. Finally, if you are building the unlike that experienced by earlier mount Tone Burst, attach speaker wires, ap- electronics hobbyists when going R2- 100,000 -ohm resistor, surface proximately 2- inches long, to the cor- from vacuum -tube -, to transistor -, to mount rect pads on the PC board (see Fig. 9). IC -based projects. You, too, are an R3, R4 -4700 -ohm resistor, surface Solder the other ends to SPKR1. For the electronics pioneer. But don't stop mount sake of proportion, and to make an now. R5 -1000 -ohm resistor, surface interesting assembly (more on that SMT project kits are beginning to mount later), select a miniature unit for that appear from a variety of sources. Pur- R6-100 -ohm resistor, surface mount speaker. chase some of those kits C1- 3.3 -11F, 10-volt, electrolytic and bu ld capacitor, surface mount them. Also, in the months to come, as C2- 0.1 -µF chip capacitor, surface Checkout and Use. Before testing you page through new issues of Pop- mount your project, spray it with the light -duty ular Electronics, zero -in on the sim- B1-9 -volt alkaline battery defluxer. Then take a nail brush and pler IMT -based projects and try SPKR1 -8 -ohm speaker scrub vigorously to remove con- creating your own SMT versions of Printed- circuit materials, 9 -volt- taminants. Don't be afraid that you'll them. In no time at all, you will be- battery snap with leads, wire, scrape off an SMC or two. If the com- come an experienced pro at SMT solder, hardware, etc. 42 ponents can't stand the rubbing project building.

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www.americanradiohistory.comAmericanRadioHistory.Com Tile Simultaneous- 'Equation Program

Let the silicon brain sitting in your den do some of the number -crunching on your electronics calculations.

BY JAMES E. TARCHINSKI

Everyone who works with elec- and the other based on his voltage two nodes to which it is connected. tronics has their own reasons for law. (For more information on both For current sources, that particular choosing it as a career or a types of analysis, refer to the article step does not apply because the cur- hobby. Some like the challenge of de- "Beyond Ohm's Law," by Paul Coxwell, rent supplied is not a variable but a signing circuits, others take pleasure in in the May 1994 issue of Popular Elec- fixed number. Therefore, it is already in building them, and a few enjoy the tronics.) We will briefly look at the ap- a form that is easy for a computer to "pleasant" frustrations of debugging proach based on KCL, which is deal with. a circuit once it's built. There is even a generally known as "Nodal Analysis." After completing those two basic group of people who enjoy elec- steps you will end up with a total of N tronics, at least in part, because of the Nodal Analysis. irkoff's Current Law equations, within which there should mathematics involved. Yes, you read states that the sum of all the currents only be references to the N node volt- that last sentence correctly: It does flowing into a node of a circuit must ages of the circuit. Unfortunately, you read "because of" and not "in spite equal the sum of all the currents flow- can not solve those equations one at or' the math involved. ing out of that node. To perform nodal a time. All the equations need to be Even the most devout mathemati- analysis, all you need to do is write solved simultaneously, and hence cian, however, eventually grows tired one KCL equation for each node of mathematicians call those types of of repeatedly performing a single se- the circuit, not counting the ground equations simultaneous equations. quence of calculations. An example node. That means that in a circuit Over the past few hundred years, of repetitive calculations is the solving containing a total of N nodes you will several methods for solving series of of a series of simultaneous equations end up with a total of N independent simultaneous equations have been that is often necessary to analyze equations. For example, in a three - developed, but the best method was complex electronic circuits. The first node circuit (N = 3), you would have created about 40 years ago. That, of few times you solve a group of simul- three equations. course, is to let a computer do it, taneous equations it's fun; after that it The next step in nodal analysis is to which is precisely what the SIM -EQ becomes drudgery and you start replace every current variable in the program was written to do. looking for some relief. equations you just generated with a SIM- EQ.BAScan provide that relief. It term based on the node voltages of Program Operation. To demon- is a BASIC program that can solve a the circuit. For a resistive element, use strate the use of SIM- EQ.BAS, let's use it series of up to 25 simultaneous equa- Ohm's law to represent the current to solve a series of three equations tions with real, constant coefficients. flow through the element in terms of with three unknown values. To obtcin Although the program was written for its resistance and the voltages at the those equations, we must first perform IBM -compatible PC's, it can easily be modified to run on any machine that v, R2 V, R3 v3 NODE 1 3052 NODE 2 1552 supports BASIC. NODE 3 But before you can use SIM -EQ to lb solve a series of equations, you need

a series of equations to work with. I la R4 1 AMP 2 AMP Therefore, let's take a look at how to 10i2 20(1 P 1* 0 solve and obtain simultaneous equations, using a sample circuit for illustration. There are two basic analysis ap- 1 proaches that can be used to solve Fig. 1. Performing nodal analysis on this three -node circuit generates equations 10, II, complex electronics circuits: one and 12. The SIM -EQ program can then be used to solve those equations to obtain node

46 based on K irkoff's Current Law (KCL) voltages V,, V2, and V.

www.americanradiohistory.comAmericanRadioHistory.Com Doing that to the circuit in Fig. 1 yields:

Eq. 1: la = lb + 1.0 LISTING 1

Eq. 2: lb = 2.0 100 CLEAR : DIM A(25, 26): KEY OFF 110 SCREEN 0, 0, 0, 0: COLOR 10, 0, 0: WIDTH 80: CLS Id = lc 120 PRINT "SIM -Eß: The Simultaneous Equation Program" Eq. 3: 130 PRINT "Copyright (c)1988 -94 by James Tarchinski" 140 PRINT where la through Id are the different 150 PRINT "Enter the number of variables /equations" 1, 2, 160 INPUT "in the system you wish to solve (1 -25): ", IN$ currents in amperes. Equations

170 PRINT : N = VAL(IN$) 3 from nodes 1, 2, ": 140 and are derived 180 IF N > 25 OR N < 1 THEN PRINT "PLEASE ENTER A VALID NUMBER! GOTO 190 Nl = N + 1 and 3, respectively. 200 PRINT Now that you have three KCL equa- 210 220 ENTER THE COEFFICIENTS tions, use Ohm's law to replace each 230 FOR I = 1 TO N current term with terms based on the / "; I; " -- --" 240 PRINT : PRINT " - - -- Column 250 PRINT circuit's node voltages and resistor 260 FOR J - 1 TO N values. Remembering that the current 270 PRINT "A( "; J; ", "; I; ") _ "; 280 INPUT " ", INS: A(J, I) = VAL(IN$) through a resistor is equal to the volt- 290 NEXT J age across it divided by its resistance, 300 NEXT I 310 PRINT you get:

320 ' AND CORRECT ERRORS 330 ' ENTER CONSTANTS v; _ (v2-v,) + 4: 1 .0 340 FOR I = 1 TO N Eq. 10 30 350 PRINT "Constant of Row I "; I; " _ "; 360 INPUT " ", INS: A(I, NI) = VAL(INS) v2 370 NEXT I Eq. 5: vi+ (vf vD-2.0 380 ' 30 30 390 PRINT INPUT "Are all the values you entered now correct (Y /N)7 ", INS 400 (V2-v3) 410 IF INS _ "Y" OR INS _ "y" THEN 530 V3 ": GOTO Eq.6: 420 IF INS <> "N" AND INS <> "n" THEN PRINT "Please enter Y or N!1 20 15 390

430 ' V1 V3 the different 440 INPUT "Row to modify: ", I where through are 450 IF I - 0 THEN GOTO 530 voltages in volts. of range! ": GOTO 440 460 IF I > N OR I < 1 THEN PRINT "Value out the 470 INPUT "Column to modify: ", J The next step is to eliminate GOTO 470 480 IF J > N1 OR J < 1 THEN PRINT "Value out of range. ": fractional elements in the above 490 PRINT "Change A( "; I; ","; J; ") from "; A(I, J); " to: "; = equa- 500 INPUT " ", INS: A(I, J) VAL(IN$) equations, which makes the 510 GOTO 390 tions easier to look at and deal with. To 520 ' * * * * ** multiply each equation by a 530 ' GAUSSIAN ELIMINATION do that, wait..." 540 CLS : PRINT "Calculating, please constant value. For "real -world cir- 550 FOR I = 1 TO N 560 HF = I cuits" it is not always practical to per- 570 B = ABS(A(I, I)) form that step, so instead, fractional 580 FOR K = I + 1 TO N 590 T - ABS(A(K, I)): IF T > B THEN B = T: HF = K components are often replaced with 600 NEXT K their decimal equivalents (for exam - 610 IF I = HF THEN GOTO 650 620 FOR K = 1 TO N1 ple,'/,o would become 0.1, 1/2o would 630 SWAP A(I, K), A(HF, K) 0.033333, etc.). 640 NEXT K become 650 IF B < 9.9999E -20 THEN GOTO 870 To eliminate the fractions in the 660 T A(I, I) multiply equations 4 670 FOR K = I TO N1 three equations, 680 A(I, K) a A(I, K) / T and 5 by a factor of 30, and equation 690 NEXT K step, combine all 700 6 by 60. In that same 710 FOR K = 1 TO N like terms to give: 720 IF K = I THEN 770 - -A(K, I): A(K, I) - 0 730 T 4V1 = V2 + 30 740 FOR L I + 1 TO Ni Eq. 7: 750 A(K, L) = A(K, L) + T * A(I, L) 760 NEXT L Eq. 8: 3V2 - V, - 2V3 = 60 770 NEXT K 780 NEXT I Eq. 9: 7V3 = 4V2 790 '

800 ' PRINT THE RESULTS answers are: ": PRINT 810 CLS : PRINT "The To make it easier to enter the above 820 FOR I = 1 TO N A(I, N1) equations into the simultaneous 830 PRINT "X( "; I; ") = "; : PRINT 840 NEXT I equation program, you need to write 850 GOTO 880 them in a standard format. That is ac- 860 ' solved!" 870 PRINT " ERRORI - Equations can't be complished by doing three things: exit... "; PRINT : PRINT "Press any key to 880 so that 890 INS = INKEYS: IF INS <> "" THEN GOTO 890 First, rearrange the equations 900 INS = INKEYS: IF INS = "" THEN GOTO 900 the unknown variables are lined up in 910 'End of Program Listing columns on the left side of the equal signs, and the constants are in a col- on the right side of the equal a nodal analysis on the circuit of Fig.1. nodal analysis is to write one KCL umn sign. Second, when a variable does 47 As mentioned earlier, the first step in equation for each node of the circuit.

www.americanradiohistory.comAmericanRadioHistory.Com not have a coefficient explicitly listed in an equation, enter a zero value as a place holder. Third, write the row numbers in front of the equations and the INITIALIZE PROGRAM & column numbers above the un- DISPLAY TITLE knowns. Note that you will always 1100-1401 have one more column than you do rows, because of the constant terms on the right sides of the equations. ENTER THE NUMBER OF Here is an example of the standard VARIABLES/EQUATIONS format, using the above equations: TO BE SOLVED 1150-2101

{11 121 131 141 Eq. 10: (1) +4v, -1v2 +0v, = 30 ENTER THE COEFFICIENTS Eq. 11: (2) -1v, +3v2 -2v, = 60 1220-320) Eq. 12: (3) +0v, -4v2 +7v, = 0 ENTER ROW CONSTANTS 1330-3901

As far as SIM- EQ.BAS is concerned, all of the numbers in the above equations are known as A(r,c) coefficients, where r is the row number that the coefficient is in, and c is the column WAS ALL THE DATA number of the coefficient. For exam- ENTERED CORRECTLY? 1400-4301 ple: A(2,3) is the coefficient in row 2, column 3, which is -2; A(1,1) has a value of +4; A(2,1) is - 1; and A(3,4) is 0. For clarity, numbers to the right of SOLVE THE EQUATIONS the (GAUSSIAN ELIMINATION) equal signs have two different 1-7901 names. Besides being called A(r,c) coefficients, the terms are also called "constants of the row" for obvious rea- / PRINT THE RESULTS sons. 1800 -9101

TABLE 1- SAMPLE OUTPUT

SIN -R0: The Simultaneous Equation Program Copyright (c)1988-94 by James Tarohineki Fig. 2. This flow shows the in Enter the number of variables/equations chart sequence of logic the SIM -EQ program. Note that in the system you wish to solve (1- 25):.3 the numbers given in square brackets refer to the corresponding line numbers in Listing I. Column k 1 ----

A( 1 , 1 ) - 6 Now that you have three A( 2 , 1 ) - _1 equations minor modifications to the program, A( 3 , 1 ) - 0 in a standard format, and are familiar but the bulk of it should run as pre-

Columna 2 - - -- with the terminology the program sented. uses, you are just about ready to use Once you've entered the program A( 1 , 2 ) - -1 A( 2, 2 ) -3 SIM- EQ.BAS to solve for node voltages into your computer and have saved it A( 3 , 2 ) -d VI, V2, and V3. Loading the program to disk (as a precautionary measure), Column - - N 3 -- into your computer is the only other you are ready for the moment of

A( 1 , 3 ) - 0 step that needs to be completed. truth -the solution of equations 10, 11, A( 2 , 3 ) - `2 If you've never entered a BASIC pro- 12. Run A( 3 , 3 ) - 7 and the program, and enter gram into a computer before, you data as shown in Table 1. Be certain to Constant of Row it 1 - 30 Constant of Row 6 2 60 might need to consult your comput- look back at equations 10 through 12 Constant of Row 6 3 - 0 er's instruction manual or your DOS while entering the data, so that you Are all the values you entered now correct manual for a complete description of can see where the data originally (Y /N)? Y the process. As given in Listing 1, the came from. Note that in the table, all Calculating, please wait... program will run on Microsoft-DOS user input is underlined, while all corn - The answers are: based computers that utilize the puter- generated text is shown in nor-

E( i ) - 18 BASICA, GWBASIC, or QBASIC imple- mal type.

8( 2 ) - 42 mentations of the BASIC program- The will solve si- E( 3 ) - 24 program the three ming language. Users of other multaneous equations after only c Preme any key to exit... implementations, or users of other few milliseconds of calculation, out - 48 machines, might have to make some (Continued on page 96)

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www.americanradiohistory.comAmericanRadioHistory.Com "SierraLand," (all decked out in pink), is where you can play Red Baron (a WWI flying game) and take part in "dogfights" against other pilots (real people and in real time, of course). There you can also find 18 holes of 3-D Golf, an incredibly realistic mini -golf game that's full of surprises, and NTN Trivia, where you can see your own scores and how you rank with other players around the country. Sierra - Land also contains games such as Paintball, Rocket Quiz, Graffiti, Boogers, and Stratego. "CasinoLand" is where you'll find Poker, Slots, Blackjack, and Roulette, using "LarryBucks" for money. (Just make a little trip to "Nurse Clot" at the "Bloodbank" if you go broke!) Or relax Anyone for a game of Bridge? In The ImagiNation you Network can play against in "Lefty's Bar" with a special friend, opponents who range from beginners to champions. send her roses or kisses, and play Ve- racity or Liar's Poker. The atmosphere there is VERY adult as "community standards" are relaxed in this land. For that reason, the area is restricted to members 18 and over, and can be password -protected to prevent young family members from entering. If you are easily offended or shocked, but still wish to partake in the activities

offered there, I recommend that you enter the room called "Polite Place." But if you enjoy a bawdy joke or two on occasion, the other rooms in CasinoLand can be loads of fun! Looming up as a volcano in the distance is "MedievaLand," which contains two fantasy /adventure /role- playing games: The Shadow of Yser- bius and The Fates of Twinion. Both are Try your hand at Red Baron, a WWI flying game. Rather than a computer, your fascinating and tough to solve. There opponent is another network member. are over 30 mazes to explore in each, while fighting an assortment of crea- line. You may talk to them, look at their (which ranks among the top ten in the tures, ranging from Gargoyles to Man - picture (or "toon" as it's often referred nation for membership), ACBL -rated ticores and Dragons. You must choose to), and invite them to play a game experts are often found tuning up for your best weapons, find proper keys with a simple click of your mouse. The their next competition. Tournaments for doors, go on various quests, etc., in game graphics are very realistic and for all games are held frequently. You order to complete them. Butyou don't colorful, and your opponents' toons can also participate in live con- have to struggle all alone, pitted appear on the screen in front of you ferences on a myriad of subjects, and against your computer. You can join a as you play. Instant conversations are there are also over 175 (at last count) party of other members to explore the accomplished simply by typing mes- bulletin boards covering a wide depths of the volcano. Experienced sages during games. range of topics to explore. players are available to answer ques- But that's just the beginning! Enter Click on the "Shopping Mall" to tions or help you find your way when the room in the Clubhouse named order Sierra games and other prod- you get lost. ucts like "INNUniversity," and you can take modems and hint books; or Or you can ask me! That is where I lessons in subjects ranging from C+ explore the Shopper's Advantage do my work for ImagiNation. It's my job programming to learning how to play Network. Just above that is the Post to greet new players and instruct

any of the games mentioned above. Office, where unlimited E -mail may them in the basics of playing. I tell In the Chess Club you can find players be sent or received between mem- them how to "walk and talk," how to ranging from beginners to world -class bers. E -mail substations are available arm themselves with weapons and 50 champions; and in the Bridge Club in the Clubhouse as well (Continued on page 92)

www.americanradiohistory.comAmericanRadioHistory.Com BUILD A FREQUENCY RESPONSE TESTER udio esponse @ester

BY RANDY CONSTAN

With it, you'll never again have to guess about the frequency response of an audio device.

Many off- the -shelf audio pro- arithmic waveform, and has an am- and vertical amplifiers provide rea- cessors, such as equalizers, plitude that remains constant. sonable accuracy. A frequency coun- enhancers, and pre- ampli- By connecting the DUT between the ter is also recommended, at least for fiers, alter audio signals even when in sine -wave sweep output and your the initial setup. their so- called "pass- through" modes. scope's vertical input, the DUT's re- The resulting frequency- spectrum sponse to the entire frequency spec- Circuit Description. The schematic losses often cause unwanted distor- trum can be easily viewed. The for the Frequency -Response Tester is tion, which can be very difficult to iso- logarithmic nature of the frequency shown in Fig. 1. The two quad op -amp late if there are several components sweep assures that the entire audio sections, U3 -c and U3 -d, are config- in an audio system. Therefore, a de- range appears as an ordered display, ured as a linear -ramp generator. With vice that measures the frequency re- in which each 1/3 of your scope's hori- switch S2 in the SWEEP position as sponse of audio components should zontal range depicts one decade of shown, the output of U3 -d is low. Zener be a welcome addition to the toolbox frequency span. In other words, the diodes D2 and D3 limit that output to of any audio -electronics enthusiast. ranges are: 20 to 200 Hz, 200 to 2,000 about -7 volts, which is the 6.2 -volt With the Frequency-Response Test- Hz, and finally 2,000 to 20,000 Hz, from reverse drop across D3, plus the for- er described in this article, you can left to right. Because the unit also gen- ward drop of D2. The internal short - directly view the frequency response erates your scope's horizontal sweep, circuit protection of the op -amp limits of almost any audio gadget right on the scaling remains stable and re- the Zener current to several milliam- your oscilloscope screen, with a mini- peatable no matter how you vary the peres. mum of fuss. If any lumps and bumps sweep rate. Because the output of U3 -d is nega- appear in the signal of a device un- Frequency -sweep generators are tive, integrator U3 -c generates a lin- der test (DUT), the mystery of your not a new or unique idea, but unfor- ear ramp in a positive direction, at a sound troubles will be solved. Further- tunately their cost can be somewhat rate determined by the resistance of more, the Tester will allow you to take prohibitive for the average hobbyist. R4 and R29, and the capacitance of corrective action, and quickly view However, you can build the Frequen- C5. A portion of that output is fed back the results. cy- Response Tester for under $50, de- to the noninverting input of U3 -d via The Tester works by generating two pending on your junk -box supplies. the voltage -divider network consist- signals. The first is a linear- sawtooth Even though this project will save you ing of R2 and R3. Because U3 -d is sweep waveform that drives the hori- some money, keep the following in basically operating as a comparator zontal input of your scope. Internally, mind: The circuit requires an initial set- with its inverting input grounded, its that signal is transformed into a log- up and occasional calibration; also, output will switch positive as soon as its arithmic waveform that spans three accuracy beyond two digits is im- noninverting input crosses zero volts. decades of voltage differential. That practical unless your scope uses so- That will occur when the positive -go- signal is applied to a function- gener- phisticated on- screen digital reading ramp reaches about +5.8 volts. ator IC to produce the second output, outs for frequency and voltage levels. Once U3 -d switches to a high -out- a sine -wave signal. The sine wave has A plain, vanilla scope will work fine put state, the operation is repeated a frequency that follows the log- with the Tester, as long as its time base with the opposite polarity except that 51

www.americanradiohistory.comAmericanRadioHistory.Com T

PL1 o +15V

C3 4" 120VAC 1 ^

C4 1 M

R1 R3 o -15V 100K 10K 1M R2 12K R4 +15V 470K J1 HORIZONTAL R15 R29 C.W. OUTPUT 10K 5MEG SWEEP R5 R24 RATE 1K - -V 1K D1 +V R16 1 N914 4 SWEEP R22 3K 10K cSb -15V D2 R6 R27 CAL S2 -a 1N4735 4.7K 100K R12 MANUAL R11 . 10K R13 FREQUENCY - D3 10K : 1MEG -15V +15V 1N4735 VN t 2 R14 R30 LEDI 1/2LF353 3.3K 1MEG L J 4700 R19 TP1 200K o +15V - u -15V C6 R25 .0047 R17 J2 10K 2 11 o 10K AUDIO R28 8 OUTPUT 100K v AUDIO LEVEL -- R26 R18 SNA, 10K 100K 4 R20 10K R21 -15V 100K

Fig. 1. As this schematic for the Frequency- Response Tester shows, there are five trimmer potentiometers, R22 -R26, that are used for calibration. But don't worry, the process is not as hard as it might seem.

diode D1, now forward biased, allows That means that when properly ad- generator, U5, is inversely propor- an additional current path to U3 -c via justed, the output at the collector of tional to its input voltage. In addition, R5. Because R5 is the resistance of Q2 will be logarithmic with respect to U3 -d's offset voltage is nominally set at much less than the combined values the input, yielding a one -decade volt- about - 7.5 volts by the combinaton of R4 and R29, the negative -going age differential for every few volts of of resistors R15 and R16, and can be ramp time is almost negligible com- input. To be more specific, if you di- trimmed precisely by the 15 -turn trim- pared to the positive ramp, and the vide the peak -to -peak voltage of the mer potentiometer, R24. That shifts the overall effect is to produce a initial linear sweep by 3, the anti -log- logarithmic -sweep waveform to suit sawtooth waveform with an ampli- generator output increases by a mul- U5, which in our circuit receives its sup- tude of over 10 -volts peak -to -peak. tiple of 10 each time the input voltage ply voltage from the ground and That is more than sufficient for just crosses another 1/3 milestone. That will -15 -volt source. Recall that our log- about any scope's horizontal input. all become much clearer when you arithmic sweep must span three de- Next, the linear ramp undergoes a see the logarithmic curve on your cades of voltage differential, which series of level and offset adjustments scope during the calibration phase means that if its final voltage were -5 R7, R8, via resistors R9, R22, and R23, discussed later in this article. volts, its initial voltage would be 1Á000 of and is then applied to the base of Q1. Next, U4 -a inverts the polarity of the that, or - .005 volts. Tiny voltages like The emitter -coupled transistors, Q1 signal, so that it starts high and ends that have to be carefully controlled, and Q2, in combination with U3 -b, low. That is necessary because the which is why R24 is used for that critical 52 produce an anti -log transfer function. output frequency of the 8038 function adjustment.

www.americanradiohistory.comAmericanRadioHistory.Com Finally, we come to the heart of the single -point grounding scheme is al- On the more critical side, Q1 and circuit, U5. That relatively inexpensive ways recommended in circuits involv- Q2 must be a reasonably matched ICL8038 function generator produces ing op -amps. In any case, a metal pair in order for the anti-log circuit to constant -amplitude sine waves, as enclosure is recommended to re- work properly. The 2N2907's specified well as triangle- and square -wave duce noise and provide stable sup- are cheap, widely available, and outputs, from 20 Hz through 20 KHz. port for output connectors. One have a lot of uses, so buy a few extra Also, its output frequency is nearly a important layout consideration is to so you can look for a reasonable perfect inverse proportional to its in- place R24 near the edge of the match. Using a DVM in diode -test put voltage, so driving its input with our board, so that an access hole drilled mode, check the nominal voltage custom logarithmic -sweep circuit wilt in the enclosure will allow occasional drop across the transistor's emitter - produce the balanced, three -de- calibration. base junction. Two transistors that cade frequency sweep we desire. Most of the components in the Test- match up within or close to 3 -digit The sine -wave output from U5 is fed er are of easy-to- obtain values, with a accuracy are more than sufficient for to the voltage divider made up of R18 few exceptions; for that reason some the project. If your DVM does not have and R19, which restores the DC offset reasonable parts substitutions can be a diode -test function, make a tempo- to zero. That eliminates the need for made. For example, power- trans- rary test jig with a 9 -volt battery, a 10K any coupling capacitors in the output former T1 does not have to be a single resistor, and the base- emitter junction stage, which makes it possible for out- 36 -volt, 300mA center -tapped type of the transistor. When the junction is put level to remain independent of as shown. Two smaller single -output forward biased (positive at the emitter frequency. The voltage- divider output transformers may be wired with their for PNP devices), you can compare is then applied to potentiometer R28 outputs in series to yield the same re- the voltage drops across the junctions for output -level control, and is subse- sult, as long as each output is at least of several transistors with an ordinary quently routed to U4 -b for a boost in 18 volts at 200 mA. DVM set on its 0- to 1 -volt range. both amplitude- and current -drive capability. Output can range from 0- to over 10 -volts peak to peak, which is e enough for testing almost any audio device. The DPDT switch, S2, has another position called "cx." In that position, potentiometer R27 controls the frequency of the sine -wave output for setup and calibration purposes. How- ever, because the output of R27 is buffered by U3 -a and routed through the anti -log circuit, the Tester can also serve as a simple stand -alone signal generator. Potentiometer R27 is also indispensable for "homing in" on a troublesome frequency during actual response testing.

Construction. The method chosen to build the Frequency -Response Test- er is not criticali; however, the easiest method is to use the single -sided PC- board layout provided in Fig. 2. If you're looking for a good PC -board project to try, the Tester PCB is an excellent choice because it is both single -sided and reasonably low in component density. When cut to the size shown, the board fits comfortably within the widely available metal enclosure noted in the Parts List. If you choose to use a PC board, a parts -placement diagram is provided in Fig. 3. If you choose not to use

a PC board, a pert -board approach 4 INCHES with point -to -point wiring will work fine. Just remember that an oversized Fig. 2. The PC -board template for the Tester is shown here in its full size of 4 X 5 zero -volt ground bus, or the use of a inches. 53

www.americanradiohistory.comAmericanRadioHistory.Com 3. For best results, you might want to use coaxial cable for the connection -R20- to R28; if you do so, ground the cable O and the off -board ground points R26 -R21- J2 R25 R16I shown in Fig. 3 to the metal chassis to IRI5 e C6 provide shielding. Jacks J1 and J2, -R17- switches S1 and S2, resistor R20, LEDI, U5 and power- transformer T1 all mount off -board as well. Within the con- -R14- -R13 - straints of the enclosure, mount T1 as J1 far R30 from the board as possible. -R19- -R18- Solder a small R23 piece of stiff wire to R22 -R8- the board at test point TP1. Make the e wire just long enough to access later Pig it with your scope probe. Finally, when LED1 + C3 + C4 -R9- S2-a attaching the power cord to S1, use some kind of strain relief or grommet I -R11.- R6 where the cord enters the case. R3 R5 I , a1 Check and re -check your U1 U2 15I connec- -MO- tions before testing the project. The 0-7 C1 C2 -R1- U3 board itself can be mounted with S2-k D1 O some insulated stand -offs, but you -R12- might want to save that final mounting step until after initial checkout. In

D3 PARTS LIST FOR THE FRE SEMICONDUCTORS U1-MC7815CT 15 -volt, positive - voltage regulator, integrated circuit S1 -a T1 PLI U2- MC7915CT 15 -volt, negative- voltage regulator, integrated circuit U3 -TL084 quad op -amp, integrated circuit S1 -b U4 -LF353 dual op -amp, integrated circuit Fig. 3. Use this parts -placement diagram as a guide when making the various on- and U5- 1CL8038 function generator, off-board connections. Note that there is an off-board ground between a few of the integrated circuit components; connect those points and ground them to the metal chassis. Ql, Q2- 2N2907, PNP transistor BR1 -1.5 -amp, 100 -PIV, full -wave agram in Fig. 3: --.08 Be careful when inser- bridge rectifier ting --.8 Q1 and Q2, because the physical Dl -IN914 general -purpose silicon _____,_ pinout of the transistors you obtain diode ______might not match the case style shown D2, D3- 1N4735, 6.2 -volt, Zener _____111_ in Fig. 3. There, the emitter pad is clos- diode ______111 est to the edge of the board, and the LEDI -Red light- emitting diode base is the center pad. Also note that RESISTORS all pads that 1 connect to off -board (All fixed resistors are %a -watt, 5% components such as potentiometers, units, unless otherwise indicated.) 8 switches, and outputs are slightly over- Rl, R18, R21- 100,000 -ohm Fig. 4. Once calibrated, your Tester sized for easy connection and identifi- R2- I2,000 -ohm should display a three- decade cation, Some pads might not seem to R3, R8, RI1, R12, R15, R17, R20- 10,000-ohm logarithmic waveform that resembles this be logically placed, which is a neces- R4- 470,000 -ohm illustration. sary sacrifice in maintaining a single - R5 -1000 -ohm Another critical item is R24, which sided layout. Extra pads are provided R6, R7 -4700 -ohm must be a 15- or 20- turn trimmer po- for the position center of all trim pots R9-470 -ohm tentiometer. It should also be obvious except R24, to accommodate a R10-2200-ohm that even though normal component wider physical variety of those parts. R13, R14- 1- megohm tolerances are not a problem, arbi- Socketing of all but the voltage -reg- R16-3000-ohm trary substitution of seemingly "close" ulator IC's is recommended. R19-200,000 -ohm resistor values is unwise in the Tester Potentiometers R27, R28, and R29 R22, R23, R25, R26- 10,000 -ohm, circuit. mount on the faceplate of the project trimmer potentiometer, PC mount Here are a few things to watch for case. Use insulated wires to connect R24 -1000 -ohm, 15 -turn, trimmer potentiometer, 54 when using the parts -placement di- them to the PC- board, as shown in Fig. PC mount

www.americanradiohistory.comAmericanRadioHistory.Com any case, plan to mount the board in such a way that a hole can be drilled to access R24 without opening the case. That is the only trim adjustment that you will occasionally need to touch up after initial calibration.

Calibration and Set -up. With all the trimmer potentiometers on the Tester's circuit board you might think that calibration is going to be a real nuisance, but that's not the case. The process is greatly simplified because you can use an oscilloscope to make almost all the adjustments visually. A separate frequency counter is also useful, but is not absolutely necessary. Another suggested tool to have on hand is a pair of walkman -type headphones. Hearing the frequency of the audio output is a good way of roughly gaug- ing whether or not you're covering the 20Hz 50 0.1KHz .3 5 7 1 2 3 5 7 10 20K entire audio range. FREQUENCY Start by centering all the trim pots, Fig. 5. By copying this scale to transparent film, you can create a custom reference graticule for your scope and greatly improve the visual accuracy of the display. WENCY RESPONSE TESTER including R24. Before connecting any tal -gain and horizontal- position con- R27- 100,000 -ohm, linear external equipment, power up the trols to produce a nine -division sweep potentiometer itself to check that correct deflection that is lined up with the left- R28- 100,000 -ohm, logarithmic unit by line. Because potentiometer power -supply voltages are present in most, vertical graticule divided by R29- 5- megohm, linear all the right places. Once you're con- nine divisions can easily be potentiometer (see text) fident that the circuit powers up cor- three, setting up the three- decade R30-3300-ohm, 1/2.-watt rectly, you can proceed. Note that it is logarithmic response we discussed normal for the TL084 (U3) to run a little earlier will be easy. it CAPACITORS warm, and for both positive and The next step is a bit tricky because Cl, C2- 330 -pF, 50 -WVDC, radial - negative regulators to become rather involves several coirciding adjust- lead electrolytic hot to the touch. If overheating be- ments. Connect the vertical input of C3, C4 -1 -pF, 25 -WVDC, radial - comes a concern, small heatsinks can your scope to the short wire you at- lead electrolytic be mounted on the regulators. tached to TP1 earlier. If you turn up the -11F, polyester C5- 0.22 For your initial setup, connect the AUDIO LEVEL control, R28, slightly, you -p.F, ceramic -disc C6 0.0047 horizontal output to the horizontal in- should hear some kind of audio put on your scope, and the audio out- sweep that appears to follow the rate ADDITIONAL PARTS AND put to your headphones. If the of the horizontal sweep (don't panic if MATERIALS headphones are stereo, it is possible that is not the case; the trim pots might SI, S2-DPDT toggle switch left just be too far out of adjustment). Flip TI -AC power transformer, 115 -VAC to hear through both right and primary to 36 -VAC secondary, with an appropriate adapter. In the S2 to the CAL position; the horizontal 300 -mA center -tapped (Stancor absence of headphones, a stereo - display will revert to a dot. Because P-8612 or equivalent, see text) system auxiliary input will do, but be the horizontal position of the dot is J1 -BNC jack careful to keep the volume level related to the audio- output frequen- J2 -Phone jack down to avoid speaker damage. cy, refer to the screen display while cord and PL1 -2- conductor power Connect a probe to your scope's using MANUAL FREQUENCY control R27 for plug vertical input. Power up the scope, set calibration. Set R27 so that the dot Printed- circuit materials, metal the horizontal time base for external, once again lines up with the left-most, chassis (Radio Shack 270 -253 or vertical and horizon- vertical graticule line on your scope. equivalent), insulated wire, solder, and set both the Then, adjust R24 to bring the audio - hardware, etc. tal amplifiers for DC measurement. With S2 in the SWEEP position and both output frequency as low as possible. Note: A drilled and etched PC board R28 and R29 set to minimum resis- You will have to calibrate that more is available postpaid from the tance, power up the Frequency -Re- exactly later, but, for now, the lowest author for $20. Contact him on sponse Tester. The scope should "bass note" you can hear without the GEnie at the E -mail address: display a horizontal sweep, the speed audio dropping out is close enough. R.CONSTAN for ordering of which you can adjust using R29. For Once the tone is established and information. calibration purposes, use the horizon- set to the lowest frequency you can 55

www.americanradiohistory.comAmericanRadioHistory.Com detect, re- adjust R27 so that the dot decade is correctly "tuned," the counter by switching it back to inier- moves exactly nine divisions to the others will all fall into place. By con- nal sweep, connecting the audio out- right on your scope screen. The fre- tinuing to adjust the decades -per -volt put to the vertical input, and mak ng quency should audibly rise. Adjust R22 trim pot, R23, along with the high log - calculations based on time /division. at this time to a point just past the level trim pot, R22, you should be able That is a bit of a hassle because it highest frequency you can hear. Re- to approximate that curve. means doing a lot of switching, and peat the process of "low" and "high" The two remaining trim pots, R25 you must remember to restore the adjustment of R24 and R22 at least and R26, adjust the purity of the sine - horizontal gain to the original nine - one more time, and then flip S2 back wave output, and should be set as division setup in between each mea- into the SWEEP position. necessary before final calibration. Po- surement. If you have a dual -trace With the SWEEP RATE control, R29, set to tentiometer R25 adjusts the duty cycle scope, you can set up one channel to maximum speed, you should be able so that the top portions of the sine represent the nine -division span of to adjust your scope's vertical sen- the Tester's horizontal output, and the sitivity and position until you can see a other to monitor the audio output. You curve starting high on the left, and will still have to go back to the original sloping downward on the right. Con- setup at least once more to touch up tinue to adjust the position and ver- the log curve with R23. Remember, tical sensitivity, abandoning the "cali- you've already set up the unit to span brated" setting on your scope as from the lowest to the highest fre- needed, so that the vertical deflec- quency you can hear, which is all that tion exactly fills the screen, from the really matters. The good news is that highest vertical division available, to once the Tester is set up, only the low the lowest. That resulting curve is a adjustment, R24, will need an occa- logarithmic progression. sional touch up. The next step is to contour the curve If you wish, use a photocopier that so that every three horizontal divisions has a scaling capability to make a correspond to a 1Áo difference in ver- copy of the log scale in Fig. 5. By mak- tical deflection. That is accomplished ing the copy on a transparent sheet, mainly with R23, which serves as a such as the ones used for overhead "decades /volt' adjustment for the projectors, you can make a custom anti -log network. Unfortunately, ad- As this internal view shows, the reference graticule for your scope justing R23 is likely to affect the total transformer in the Frequency- Response and greatly aid the visual accuracy of vertical amplitude, so you might have Tester should be mounted as far from the the display. to "see -saw" between R22 and R23 board as the project case allows. until the desired curve is obtained. Using the Tester. For accuracy at Trim pot R24, which mainly affects the wave equal the bottom half, while the low- frequency range, always al- 'top" portion of the vertical deflec- R26 is used to trim out distortion. Those low the Frequency -Response Tester to tion, will probably not make much of a controls do not treat all frequencies remain powered -up for a few minutes difference. In the end, your curve equally, so waveform purity must be prior to running response tests. As should resemble the one shown in Fig. optimized at a specific frequency. The we've seen, the Tester's entire first de- 4 as much as possible. author recommends a mid frequency cade from 20 to 200 Hz depends on The curve in Fig. 4 assumes that your of about 1000 Hz. Using your scope in the stability of a very small control volt- scope graticule has eight major ver- its normal internal -sweep mode, set age, which usually takes a little time to tical divisions. Using the top line as a the tester to CAL, and observe the au- settle. To test the response of an audio reference, note that the total deflec- dio- output waveform while making device, simply connect the Tester's au- tion is eight divisions down at the right the above adjustments. In the end, dio output to the DUT's input, and the edge of the trace. Because the width both controls should be somewhere DUT's output to the vertical input of of the trace has been set at nine divi- near their initial center position, or the your scope. sions, you can easily divide the display frequency span might suffer. (A note of caution is in order here: into three sections. If you start at the The final step in calibration is simply Some power amplifiers have outputs right and move left, you'll see that the to repeat the setups of R24, R23, and that cannot be ground referenced. In deflection from the top line is 1/10 less R22, this time with a frequency coun- such cases, a dual -channel scope each time we cross 1/3 of the total ter added to the audio output. In- used in differential mode via both in- width. So, the total deflection is 8, .8, stead of using your ears for the low- puts is the only safe way to monitor the and .08 vertical divisions at 9, 6, and 3 and high- frequency adjustments, use amplifier. Also note that power ampli- horizontal divisions respectively. Ob- the frequency counter to obtain val- fiers usually require output loading for viously, - .08 divisions is not really visi- ues of 20 Hz and 20,000 Hz. For that proper operation.) ble, and in fact, the start point of the final calibration, make sure the unit When your test set -up is complete, curve should really be - .008 divisions, has been on for a few minutes to al- switch S2 to c t mode, and select a which is certainly not visible. Because low it to stabilize. middle frequency using the MANUA,. FRE- the anti -log network defines the If no frequency counter is available, QUENCY control, R27. Then, adjust the 56 curve, we can assume that once one you can use the scope as a frequency (Continued on page 93)

www.americanradiohistory.comAmericanRadioHistory.Com Generating square waves is easy when you follow the simple "recipes" svo* in this cookbook.

Sop BY JOSEPH J. CARR Square waves are among the one high and one low, each of equal most useful waveforms around. length. The total period required for They are used to make the square wave cycle is: qualitative tests of amplifier and pas- T =t1 +t2 sive- network circuits, and for radio troubleshooting. Square waves are while the frequency (t) is: even used as clocks in digital circuits. waves so useful for testing purposes is f = 1/T Fortunately, square waves that are that they contain a large number of stable in both amplitude and fre- A negative, monopolar square harmonics, or integer multiples of the quency are relatively easy to gener- wave is shown in Fig. 1B. The negative fundamental frequency. Because the ate using the following circuits. Let's square wave is similar to the positive symmetrical, bipolar square wave has take a look. one shown in Fig. 1A, but in the nega- both baseline and time symmetry, it tive square wave, a high is defined as produces only even -order harmon- Types of Square Waves. Figure 1 0 volts, while a low is some negative ics- harmonics with frequencies that shows five different types of square potential (- V). are even multiples of the fundamen- waves. For all five, the signal is inher- Another square wave is the sym- tal-as shown in Fig. 2. Theoretically, ently binary -it quickly jumps be- metrical, bipolar square wave of Fig. those harmonics extend to infinity, but tween two values ('high" and "low'). 1C. In that type of square wave, the in reality, a good, sharp, clean square Because the square wave never per- high and low voltages are equal po- wave has even -order harmonics out manently remains at just one level, it is tentials above and below the voltage to about 1000f. said to be astable. For that reason, axis. A variation on that is the offset, Square waves can be generated most square -wave generators are bipolar square wave of Fig. 1D. That by digital TTL and CMOS IC's, 555 - called "astable multivibrators." wave has a DC offset voltage that timer-based circuits, and operational A positive, monopolar square wave prevents it from being symmetrical amplifier ( "opamp ") circuits. Let's look is shown in Fig. 1A. For that type of around the voltage axis. The square at each in turn. square wave, the two ideal voltage wave shown has a positive DC com- levels are zero volts and some positive ponent added to it, but that offset TTL Generators. TTL integrated cir- voltage (V +). In transistor -transistor voltage could be negative instead. cuits have a 74 or a 54 as the first two logic (TTL), the low level is anything Figure 1E shows another asym- digits of their part numbers. They are below 0.8 volts and the high level is metrical square wave. In that case, powered by a 5 -volt DC supply. Be- anything from 2.4 to 5 volts. Non -TTL- however, the lack of symmetry is not cause a high level in TTL IC's is any- based square waves of that type across the voltage axis but in the rela- thing from 2.4 to 5 volts, a TTL signal is might use different voltage levels. For tionship between t1 and t2 -t1 does said to change state when it crosses a example, while CMOS chips can gen- not equal t2. The percentage of the 2.4 -volt threshold. erate TTL- compatible voltage levels, time the wave is high, or: Normal TTL chips operate at speeds they are often used in circuits with of up to 18 MHz, with some cooking 100% x t1 /(t1 + t2) much larger high -level voltages. along at 25 MHz. Special types go up Figure 1A also shows the time rela- is called the "duty cycle" of the square to 80 MHz or more. tionships of a positive, monopolar wave. The inverter is a basic element in square wave. A total cycle consists of One of the things that make square TTL -based square -wave generators. 57

www.americanradiohistory.comAmericanRadioHistory.Com For a typical CMOS chip, a signal is HIGH HIGH V+ o said to change state when it crosses rt1 t2 the voltage half -way between the LOW LOW supply voltages. For example, when a o V- + mi12 -volt supply is used, the threshold is 0 volts, and when a single 12 -volt A t3 supply is used, the threshold is 6 volts. The first digits in a CMOS -chip number V+- are generally 4 or 45. HIGH A Schmitt trigger is a special circuit V+ - that obeys slightly different rules than DC do other forms of digital gates. For COMPONENT o o example, when the 4584 hex inverting Schmitt -trigger IC is operated from a 5 LOW -volt power supply, the output state V- will change on positive -going input signals at 2.9 volts, and on negative - C D going input signals at 2.3 volts. The difference between the 2.9- and 2.3- volt signals is called the "hysteresis V+ -T band." t2 Figure 4 shows a 4584 inverter roof t1 the total 4584) used in a very simple V- - square -wave oscillator circuit. Be- cause the 4584 is an inverter, a low at E input pin 1 produces a high at output Fig. 1. Here are the five main types of square waves: positive monopolar (A), negative pin 2, and consequently, a high input monopolar (B) , .symmetrical bipolar (C), asymmetrical bipolar (D), and time produces a low output. When power is asymmetrical (E). initially applied, capacitor Cl is discharged so the input sees zero volts (it Those components can be either dis- is low); the output is therefore high, crete inverters (such as the 7405), or w allowing Cl to charge from the output NAND gates (like the 7400) or NOR gates voltage at a rate limited by the time (for example, the 7402) with their in- 7:1 constant R1C1. When the voltage at puts tied together to form an inverter. the input reaches the Schmitt trigger's Figure 3 shows a typical TTL ring os- positive -going trip point, the 4584's in- I I i cillator that will produce square tt put sees a high. That results in a low 21 4f 61 81 10021 992f 1000f waves in the 500 -kHz to 10 -MHz range. FREQUENCY output, which causes Cl to discharge In that form, is it made from three sec- Fig. 2. The frequency spectrum of through R1 until the voltage drops be- tions of a 7405 hex inverter chip. symmetrical square waves consists of the low the negative -going threshold. The The circuit's frequency is set by the fundamental frequency and a large capacitor will continue to charge and values of Cl and R2. The value of Cl number of even harmonics. discharge between those two levels should be in the range of 390 pF to at a frequency of approximately 0.005 µF while R2 can vary from 1 to 0.72R1C1, 3.9k ohms. It is common to use a cir- Figure 5 shows a CMOS square - cuit like the one in Fig. 3 to generate a wave oscillator based on inverters i'(::1r frequency that is higher than the one NAND or NOR gates wired to act like in- needed, and to then divide the fre- verters), which is similar to the ring os- quency with a series of TTL counter cillator shown previously. Unlike some circuits cascaded together. CMOS inverter -based circuits, the cne in Fig. 5 will produce a square wave CMOS Generator Circuits. The CMOS family of digital integrated circuits operates at lower frequencies than the TTL family, but in return, CMOS IC's consume less power. While a typ- Fig. 3. A TTL ring -oscillator circuit uses ical TTL device might dissipate milli - an odd number of inverters in an astable watts of power, an equivalent CMOS configuration. device dissipates microwatts. Like TTL IC's, CMOS devices can also be compatible. However, many CMOS Fig. 4. A CMOS. inverting. Schmitt - powered from a 5 -volt supply, and de- devices can be powered at higher trigger square -acne oscillator requires 58 pending on the situation, might be TTL voltages. very few components to function.

www.americanradiohistory.comAmericanRadioHistory.Com OUTPUT 10,000 ohms and 1 megohm, while fo = 1.44/((R1 + 2R2)C1) the value of Cl should be 100 pF or more (the maximum capacitance is The duty cycle of the 555's square - not limited theoretically, but a prac- wave output is determined by the re- tical limit exists when the leakage re- lationship between R1 and R2, and is sistance of Cl is of the same order of given by: magnitude as R1). Duty Cycle = (R1 + R2) /R2 'SEE TEXT 555 -Timer Oscillators. The 555 Fig. 5. This CMOS, inverting square - Linear IC Generators. Several wave oscillator can be varied over a timer, with the possible exception of integrated circuits can wide range. Note that R2 should be ten either the 741 operational amplifier or types of linear The times the value of RI, as shown. some microprocessors, is probably be used to make square waves. the most popular IC. That is because simplest of those is the operational the 555 is versatile, low -cost, and be- transconductance amplifier (OTA). The only components in the simple #2 haves itself (which means that designing 555 projects is relatively easy). circuit shown in Fig. 8 are a CA3048 The 555 is used to make monopolar OTA, a feedback resistor (R1), and a f/2 square waves that can be either TTL timing capacitor (CI). The output fre- compatible (V+ must be 5 volts DC), quency is approximately given by: or CMOS compatible. Any power - f = 1 /(23TRIC1) supply voltage from 4.5- to 18 -volts DC can be used, as the voltage sets the Timing resistor R1 should be from 1 megohm to 3.9 megohms. When R1 is -wave oscillator, value of the high state. Fig. 6. This square of a greater value, the circuit some- based on the 4047 CMOS device, has v+ times stops oscillating, depending complementary half- frequency outputs. C3 upon the specific CA3048 used. .1 that has a 50% duty cycle. There are -Amplifier Gener- two resistors used in that circuit; R1 is Operational ators. The operational amplifier is used to set the operating frequency OUTPUT one of the most useful linear VC's and R2 is approximately 10R1. Typical made. When introduced in the late values for R1 and R2 are 100,000 ohms 1940's (in vacuum -tube form), the op- and 1 megohm, respectively. The val- amp was intended for performing ue of Cl is less than 1000 pF The oper- mathematical operations in analog ating frequency can be from 0.1 Hz to computers Very rapidly, however, de- 1 MHz, depending on the values of R1 signers realized that the op -amp and Cl, and is determined from: Fig. 7. Of course, the old 555 timer can could be used for a wide variety of fo = 1/(2.2RIC1) be used as an astable multivibrator to applications other than computing. generate square waves. However, for the The transistor soon introduced more where fo is in hertz, R1 is in ohms, and circuit shown, they will not be people to the op -amp, but it wasn't Cl is in farads. symmetrical. Another CMOS square -wave gen- until the advent of the integrated cir- the complexity of the operator is shown in Fig. 6. That circuit is cuit that based on the 4047 multivibrator cir- amp became an internal affair. The cuit, which can be used for either result was a simple amplifier in which monostable ("one-shot") or astable the transfer function was set by ma- applications. In the configuration nipulating the feedback. a op- shown in Fig. 6, the 4047 is an astable Figure 9A shows common multivibrator. There are three outputs amp square -wave generator circuit. It paths: one sets the from the 4047. The first is the oscillator uses two feedback DC level atthe noninverting input ( +), (OSC) output, which is connected di- Fig. 8. An operational transconductance while the other is the RC timing net- rectly to the internal oscillator circuit. amplifier, square -wave generator circuit if the feed- The other two outputs, Q and 9, are looks much simpler than it sounds. work (R1C1). In general, complementary to each other and back constant (ß) is: the frequency of The 555 can be connected in either operate at one -half ß = R3 /(R2 + R3) the internal oscillator. monostable or astable configura- The output frequency is set by tim- tions, but for continuous square the output frequency is set by: as in waves, the astable version is used (see ing components R1 and Cl, the fo = 2RICILn((1 + ß) /(1 - f3)) last equation, but the Q and 9 outputs Fig. 7). The square -wave signal ap- obey: pears at pin 3 of the 555, while timing But, as with many circuits, a simple signals are processed at pins 2, 6, and assumption can simplify the equation fo = 1/(4.4RIC1) 7. The output frequency of the 555 quite a lat. If we assume R2 = R3, then The value of R1 should be between astable multivibrator is found from: the equation reduces to: 59

www.americanradiohistory.comAmericanRadioHistory.Com V+ C2 put, then the output is high; if the inver- polarity. The process then repeats it- ting is input more positive than the self. The high time is ta and the low noninverting input, then the output is time is tip, while the total period is: low; if the two inputs see the same T =ta + tb potential, then the output is zero. Assume on initial turn -on that the and the output frequency is lit capacitor is discharged, so capacitor The circuit shown in Fig. 9A pro- voltage Va is zero. According to the duces a time- and voltage -sym- rules for operational amplifiers, that metrical square wave. We can alter forces a high output. Capacitor Cl that time symmetry by making either can now charge under the influence of the following two modifications to of +Vsat and the RIC1 time constant. the circuit. After time ta expires, the capacitor The first modification is shown in Fig. voltage Va reaches +Vi, so the out- 10. That circuit uses two resistors in the put snaps low to -Vsat. At that time, timing network, and a pair of PN -junc- A the low segment of the output wave- tion diode switches to select which form begins, and Cl begins to dis- resistor is used at any given instant. charge under the influence of -Vsat. Diodes D1 and D2 are backwards with It then recharges under the opposite respect to each other, so they con- duct on alternate polarities of output voltage Va. When the output is high, D1 is forward biased and D2 is reverse biased. As a result, R1 is used with Cl to time the circuit. When the output state changes to low, D1 is reverse biased and D2 is forward biased. In that case, R2 times the circuit. Because R1 and R2 are not equal to each other, their timing is different, so the output wave - VO form's highs and lows are not equal. A limitation on the circuit in Fig. 10 is that the duty cycle of the output square wave is fixed. The second e modification to the circuit in Fig. 9A is *CHOOSE YOUR OWN OP-AMP Fig. 9. This operational -amplifier the variable- duty -cycle square -wave Fig. 10. Here is an opamp -based square -wave generator (A) produces a generator shown in Fig. 11. That modi- square -wave generator that uses diode 50-percent duty -cycle signal. That is fication uses a DC -offset circuit (com- because both the charge and discharge switching to produce a fixed duty cycle posed of R4 and R5) to inject a current for Cl flow through RI. The other than 50 percent. second current (12). Because resulting charging and output waves are of that v- bias, the shown in B. half cycle when li and 12 V2 R5 have the same polarity is shorter. fa = 1/(2.2RIC1) 10K When R5 is set to the mid -point, the DUTY -CYCLE R4 Figure 9B shows the annotated tim- CONTROL value of V2 is zero, and the output 560K waveform ing waveform for the above circuit, V+ has the usual 50% duty cy- with the capacitor charge /discharge 121 cle of the unmodified circuit. curves superimposed on the output The circuit shown in Fig. 11 can be R1' waveform. Because the op -amp is modified to perform pulse -width powered from a bipolar supply, out- modulation. For that, one end of R5 is put voltage Va jumps between +Vsat grounded and the other end is con- and -Vsat. The noninverting input is o nected to a source of triangle, biased to voltage V1, which is a frac- R2 sawtooth, or sinewaves that modu- tion of output voltage Va according vi 2.7K lates the duty cycle of the square - to: vo wave signal. The modulating signal should vary over a substantial portion Vi = Vaß = VaR3/(R2 + R3) R3 C1. 2.7K of the V+ to V- voltage range (but Since R2 = R3: -K not more than those values) in order to produce maximum duty -cycle Vi = V0/2 'SEE TEXT vari- "CHOOSE YOUR OWN OP-AMP ation. The rules for the operational ampli- Square Fig. 11. Use R5 to adjust this variable - -wave generator circuits are fiers used in the above nonlinear cir- duty -cycle square -wave generator. That easy to design, easy to build, and are cuits are simple: If the inverting input is potentiometer controls 12 to vary the extremely useful for a wide variety of 60 less positive than the noninverting in- timing. applications in electronics.

www.americanradiohistory.comAmericanRadioHistory.Com TROUBLESHOOTING '= ASO REPAIRING

www.americanradiohistory.comAmericanRadioHistory.Com ANTIQUE RADIO

By Marc Ellis Ifs time once again to saved up and put together, formula from Ghirardi's I give our readers the floor. in a special column or two, Radio Physics Course) Millar Receiving mail from you is three or four times a year. built one from aluminum fá9 certainly one of the most Since it does take an- and masking tape -rolling enjoyable parts of this job! other couple of months up the "sandwich" into a

Mailbag Time It's instructive, it's fun, and it after I write a column for neat cylinder. keeps me in touch with your the magazine to hit the Many folks who don't Again! interests -which is a great streets, it can be six months have the patience to fool help in planning the col- or more before you see with a cat's whisker (myself umn. your request or comment in included) like to substitute a print! So please be patient. modern semiconductor diode for the galena while CRYSTAL SET experimenting with crystal - COMMENTS set circuits. George H. Haby The series of articles on (Altadena, CA), who is 88 the NBS crystal set drew a years old, goes us one bet- lot of attention, and I'm still ter by using four diodes receiving comments from hooked up as a standard readers on that subject. full -wave rectifier. The input Let's start with one from terminals are connected Rudolf Mangold (Penn Val- where the crystal normally ley, CA), who remembers goes; the output terminals building crystal sets with his to the headphones. dad in the early 1920's. Even Vincent Bashore (San though the NBS set was Ysidro, CA) received his first designed to be scratch - crystal set as a birthday built, Rudy doesn't under- present in 1928, then got stand why a capacitor into building them. He once wasn't used across the gave up school lunches for Here's a pictorial of the reproduction 1922 British crys al set phones. The phones act as a week to accumulate built by reader D.B. Millar from plans in Practical Wireless an RF choke, attenuating parts money for a set using magazine. The set was tuned by swinging the front pancake coil the flow of current through a coil wound on a maple over the back one. the crystal unless bypassed. rolling pin and tuned by a "If we would show a crystal brass slider. My way of responding to set without a capacitor at A photo received from your letters is to acknowl- our radio club, we would Robert S. Davey (Frankfort, edge them on these be laughed at." Rudy and IN) shows a set he built from

pages. If I tried to respond his dad made their own plans in Popular Mechanics personally, particularly to phone capacitors by sand- (January, 1977). The pub- the many requests for sche- wiching alternate layers of lished set used a 31/2 -inch- matics, technical advice, metal foil and tissue paper. diameter, cylindrical salt

and other information, I D.B. Millar (Annapolis, MD) container as a form, but wouldn't have time to write built a kind of British equiv- Bob seems to have used Antique Radio. alent of the NBS set from some other kind of tube. For

So instead I share the vintage plans published in flexibility in experimentation, letters, referring the ques- the UK magazine Practical he substituted clip-lead coil tions and requests to the Wireless (September, 1972). connections for the perma- readership at large and It was offered as a means nent ones suggested in the passing along the many infor listening to the BBC 50th article. teresting tips and other anniversary program A. Ross (1926 Hafor Circle, pieces of information. For (November, 1972) com- Iowa City, IA 52246) is look- maximum impact, and in memorating the first ing for two of the refer-

order not to interrupt the broadcast in 1922. That set ences I mentioned during flow of ongoing projects or didn't have a phone ca- the NBS set series: How to 64 stories, your letters are pacitor either, but (using a Build Your Radio Receiver,

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Extended Play Robert S. Davey's version of the "salt bon" crystal set described in Popular Mechanics for January 1977. Clip leads make it easy Telephone to experiment with coil taps. Recording System - $129.50

- Automatic - Crystal Clear - Easy to Use - edited by Banning and are available (the cost is Connects to Any Phone - Automatically controls Cockaday (Popular Radio, reasonable) from the Popu- and records both sides of the conversation on our Inc. 1924), and Radio for lar Electronics Bookstore. extended play recorder. Caution - check local an alerting beeper. Everybody by Austin C. Write them directly (not laws as some states require Ready -to -Use System only ;129.50 Lescarboura (Scientific though this column) and TAP2OX FREE CATALOG with order- or send St.00 PaH American Publishing Co., inquire. If you need several MC, VISA, Check, Cash or C.O.D. 1922). I've seen the former issues, try your local library. 'ÌÌW 'UNLIMITED Send or Fax Orders to: Dept pe16 offered as a reprint but, Many subscribe to Popular PO Box 719, Amherst, NH 03031 unfortunately, don't recall Electronics, and most have Orders: 800.221 -1705 FAX 603ó72.5406 Tel 603-673.4730 the source. copy machines. M. Deluca (E. Setauket, NY) requested the address HELP WANTED Earn $1000 of James Knight, who built Mrs. Tanya Dejong (1453 the speaker -volume crystal Garvin St., Prince George, A Week While You Learn High set shown in the September, BC, Canada V2L 321) is Paying VCR Repair. 1994 mailbag column. Its looking for service info on a Earn While You Learn . . . 222 Greenfield Ave., Vicking (could this be Vik- Secrets Revealed . . . Tullahoma, TN 37388. ing?) NA. 95. Larry Stanley Train at Home Finally, several folks are (RT 1 Box 166, Delta, AL If you are able to looking for copies of cer- 36258) is looking for some- work with small tain installments of the NBS one to repair his Zenith hand tools and pos- set series. M.R. Angermiller 9H081. John H. Rodriguez sess average me- (1239 Yale St., Houston, TX (123 Colonels Lane, chanical ability, you 77008 -6959) needs January Weymouth, MA 02189) could earn top dol- lar part time or full and May 1994. Gerry Hoye needs help repairing the time. Ourlearn by doing method teaches you how (will (Department of Civil Engi- drive -motor circuitry to work on VCR's without boring unnecessary neering, 220 Civil /Electrical not run on high speed) of electronic basics. Engineering Building, Uni- his Akai Model M -7SP reel - For Free Information Package Send Coupon to: versity of Alberta, to -reel tape player. Foley -Belsaw Institute, 6301 Equitable Road, Kansas City, MO 64120 Edmonton, Canada T6G Could a Crosley expert (Clock oo. Box Only) 1 2G7) needs May and June. give Randall Thacker (4216 1 Check VCR VCR Repair, Dept. 62273 Cliff Stearns (803 W. Malone East Hono St., Phoenix, AZ or another High Paying Computer Repair, Dept.64171 Dr., Connersville, IN) would 85044) a hand? He's work- Career TV /Satellite Dish, Dept. 31064 Model E -15WE and Field like all the issues (January ing on a Advance VCR Repair, Dept. 65033 1994 and April through Au- is having trouble getting the Camcorder Repair, Dept.66043 gust 1994). All those knobs to stay on their shafts. Fax Repair, Dept. 67043 individuals offer to pay It seems that the triangular Since 1916 Printer Repair, Dept. 68042

copying costs. plastic inserts are worn. Name Here's a suggestion to Randy would like to find Address anyone looking for back some used or reproduction City issues. If you need only a replacements. 65 copy or Iwo, they most likely Randy also recently ac- I State Zip J CIRCLE 154 ON FREE INFORMATION CARD

www.americanradiohistory.comAmericanRadioHistory.Com quired an Echophone EC1, Eagle Ave., West PUBLIC LEDGER- PHILADELPHIA, SUNDAY MORNING, FEB: and wanted to review my Hempstead, NY 11552) sent Schematic Diagram and Assembly of the `7relan Five's July through October 1987 us a shot of his recently restoration series on that purchased Pilot G -184. He'd set. Randy couldn't find like any information he can 1987 copies of Popular get on the set, especially Electronics in his library. an estimate of its rarity and (Here's a hint, Randy: Back market value. then, this publication was Craig Fiedler (22253 known as Hands -on Elec- Pheasant Court, Hutchinson, atmrarm nua4Ar w su -mars n4" 4Q, tronics!) MN 55350) needs an in- wY w Anyone U..tMwYM.sYN.tY tn.Mr a.aYO Ny. Yer care to share struction book and .r. w w` i o z°' 9i l : .w k . their methods for (1) remov- calibration information for a Awns or tY..Y.. 11.. .M ing rust from chassis and Sprague Tel -Ohmike Model transformers and (2) repair- .e. TO -6 Capacitor Analyzer. He Me4sWtWYs = Ñ ,sYY .ws O.N.OLLY ing large holes 0.130 w in speaker found a 1968 date stamp- h ° cones? Please contact .y . ed inside the instrument .NY.tltre. O.a Glenn Woodward (4003 and wanted confirmation :=r.a da tW Y Y...... ,. .. Pine Hill Blvd., Racine, WI that the analyzer could be Sent in by reader John Lombardi, the radio section from a 1927 53403). A schematic and so recent. I All can say is Sunday paper conveys some of the excitement of the 1920's radio service info for a Hal - that it makes sense to me! craze. licraffers S -38C are being The earlier Model TO -4 that sought by Howard Cum- I restored on these pages a tector from the ARRL to Terry Schwartz mings, 4700 Morris NE, few months ago was a late Handbook and a "Poor (Shoreview, MN) for the Albuquerque, NM 87111_ . 1950's instrument. Man's Williamson Output latest set of photos of his Howard could also use Stage" from a 1950's Radio collection. We'll run them some restoration advice on THIS `N THAT News. soon, Terry! Another thank - that set. Please get in touch Speaking of the TO -4 res- When renovating his you to Robert Davey who with George B. Henley, toration, Harry Alenik home, John Lombardi (sor- sent me some interesting WA7GSN if you have infor- (Hawthorne, CA) writes that ry, I don't have John's photocopies from recently - mation and /or schematics he found it helpful in restor- location) came across acquired Radio -Craft and on the following test equip- ing his somewhat earlier some newspapers stuffed in Short-Wave Craft maga- ment: a Knight TEN -2 CB TO -3. After replacing all the the wall as insulation. In- zines of the 30's and 40's. Checker, and an EMC caps, including the filters, cluded were a couple of particularly enjoyed the ad- (Electrical Measurements he fired it up and was quite pages from the radio sec- vertising material on Corp. of New York, NY) pleased with its perfor- tion of the Philadelphia Hallicrafters, Doerle, and Model 801 Resistance -Ca- mance. Harry says that the Public Ledger (February 27, Echophone sets. pacitance Comparator TO -3 is more accurate than 1927), and John was kind Louis Duval (Quebec, Bridge. his Heathkit Digital L -C enough to send copies. Canada) gets a thank -you Christian Nielson (233 bridge or his EICO model Looking at those old -time for sending info to reader 950 B. large pages stuffed with Barry Stephens (Austin, To Keith L. Fender (Mount ads, program listings, and who inquired about the Vernon, WA), who signs him- radio -related news, you Type KC Loctal tube (and self "Your Antique Reader," can really get a feeling for for including a copy for my remembers starting his ca- the "Radio Craze" of the files). And, finally, Tom Byers, reer in electronics with a 20's. Come to think of it, if WB9YTG would like to ex- "Quaker Oats" crystal set in you'd like to get an idea of press his appreciation to the early 1920's. He sent a what those radio pages the several folks who re- schematic and parts list of look like, check the corn - sponded to his inquiries for an AC- operated IRE-with puter section of the service info on the Hal - Meissner tuning capacitor business pages in your cur- licraffers S -40 -A. He now has and coils-that he originally rent Sunday paper! it working and is restoring built (I would guess) in the Thanks to Robert Fleischer several other communica- late 30's. He's used it reg- (Lake Tahoe, CA) for the tions receivers.

ularly over the years, long note. I enjoyed read- Do you have any ques- making modifications and ing about your career as a tions or comments for improvements This grand- looking Pilot from time to circuit designer and your inclusion in the next G -104 console was recently time. For example, the origi- "retirement" as a repairer/ mailbag'? Write me c/o purchased by Christian nal grid -cap tubes were restorer of hi -fi sets, indus- Antique Radio, Popular Nielson, who seeks changed to single-ended trial gear, musical - Electronics, 500 -B Bi -Coun- information on its rarity and types, and the set now instrument electronics, and ty Blvd., Farmingdale, NY 66 value. sports a low- distortion de- antique radios. Thanks also 11735.

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171 Pro- I to Ex- 8P182-MIDI '1 BP80 /98- Popular c..Nr,o,° #160 -Coil Design l BP271 -How \:. Popular Modernize and jects...$6.95. Provides Electronics Electronic Circuits - c"'n.-WA and Construction Man- pand, i epga n,.r. Repair PC's and Corn- .: practical details of how Circuits Books 1 and 2...$11.90. ual...$5.95. A complete - All the a to interlace many popu- ' ° ° "' Contains a wide range of book for the home build- patibles...$7.75. circuits which are ac- er on how to make RE. practical information you lar home computers of different manufactures f companied by text giving IF, audio and power are likely to need to up- rb / with MIDI systems. Also a brief introduction. cir- chokes and transform - grade your PC and tom- 1©, . - ` - , covers interfacing MIDI ' cuil description and spe- ers. Practically every - patible. Also contains \ information and fl- equipment to analog and cial notes on construc- possible type is dis- useful l synthesizers: tion and setting -up that cussed and calculations lustrations to help you 'l' \ percussion amply illustrated. may be necessary. are explained in detail. with repairs.

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- BP266- Electronic `] BP329- Electronic BP319- Making BP303- Under- PC Software Modules and Systems EvOr°o° uwi° Music Learning Pro- r,t,,k,,,,, MS -DOS MS-DOS Work for You UNDES$TANDIMB standing i v,.,. Covers main for Beginners...S7.25. c °"°'PrO1°Ct' jects...$6.25. A begin-be m- w,,,R ,,, - $6.50. What you need PC SEFTWRBE ..S6.95- PC Shows the reader how to ner's book that will assist to know first, comes first, types of software, details of typical build a number of simple you in assembling such _ however the text is writ- giving the basics of how analog and digital circuit projects as the Elexylo- ---' ` ten in a circular style so - - uses, used and their modules, all suitable for , '. phone, Gildaphone, that the reader can start they are and limitations. Each chapter battery operation, and all Melody Ranger, Cord- anywhere in the text. ..0> This book is relevant to 1-,\)' covers popular software based on only 1 or 2 't maker, Appealing Hand- - '" of a simi- transistors or ICs. bells, Electronic Sol-Fa, all versions of both MS- and programs Tune -up Box and more. ° DOS and PC -DOS. lar type.

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' intro - dBASE, is difficult to ,,,,,,,, circuit demonstrator that existing spreadsheet Ir. concentrates on ^ by t is used throughout the users upgrade to 1 -2 -3 ¡ : ducing technique ;31', master without help. This _i 1$ in at the book helps you spend book to introduce cam- Release 3 1 which has ti looking depth st ability to work 3 -di- ; most frequently used ii li your time using dBase. mon electronic compo- the ¿ . ! and more easily under- not setting it up. A user's nents and how these mensionally with both .. multiple worksheets and e ''_, stood computer instruc- guide that covers all the d components are built up .' tions. 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 #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 #226 -How to Build Advanced SW Receivers $5.75 BP93-Electronic Timer Projects $5.50

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 $1.50 Total price of merchandise $5.01 to $20.00 $2.50 i Shipping (see chart) Name $10.01 to 2 0.00 $3.50 i Subtotal S $20.01 to 30.00 $4.50 Address Sales Tax (NYS only) $ $30.01 to 40.00 $6.50 Total Enclosed Cityty State Zipp $40.01 to 50.00 $6.50 i above $8.00 PE2 Allow 6 -8 weeks for delivery $50.01 and All payments must be in U.S. funds! 67

www.americanradiohistory.comAmericanRadioHistory.Com COMPUTER BITS

By Jeff Holtzman very year or so, the 1994 issue) even pro- HIERARCHIES computer industry falls claimed that objects were Let's start with hierarchies; in love with some concept. dead. see Fig. 1. If you understand The marketers take hold of It may no longer be fc :h- how to organize files under an idea and hype it nearly ionable, but make no DOS, you understand the to death, in the process mistake: Object technology concept of a hierarchy. In totally diluting its meaning. is important. Object tech- DOS, the root directory In the meantime, the technology is in fact alive and might contain multiple sub - nical people keep on well, and flourishing in Sil- directories, each of which Objects pushing forward, figuring icon Valley, as well as could contain multiple sub - that eventually the idea software shops worldwide. directories, and so on. really will take hold in some All the influential software Under DOS, any given di- practical way. Networking and computer companies rectory can have multiple are deeply committed to subdirectories. On the other KINGDOM object- oriented technology. hand, a given subdirectory C:\ That includes IBM, Apple, can belong to only one PHYLUM Microsoft, HP Digital, directory. C:\FINANCE CLASS Borland, and numerous We use the hierarchical C:\FINANCE\1992 others. structure to ORDER organize our There are object- oriented work. For example, off the C:\FINANCE\19921JAN FAMILY operating systems root directory, we might GENUS (OpenStep, Cairo), object - have subdirectories for stor- oriented programming lan- ing text files, finances, SPECIES guages (Smalltalk, C +), a games, utility programs, few object- oriented ap- and so on. Some of these HIERARCHICAL DOS BIOLOGICAL plications programs, and might be further subdivided TREE ANALOGY ANALOGY even object- oriented hard- according to year (1990, Fig. 1. Hierarchical trees are a common way to represent rela- ware devices (e.g., 1991 ) and so on. And tionships among families, types of animals, units of an miniature sensors that oper- outside the computer organization-and computer software. ate on a network and world, we're surrounded by provide feedback about many different hierarchical was one such concept that the operational state of an structures, even though we just kept getting pounded automobile or manufactur- don't normally think of them and pounded. Today, $100 ing process). as such. and a little shopping will If you're brand new to For example, families are get you a pair of Ethernet computers and program- hierarchically structured. If cards and a copy of Win- ming, you may wonder you're like most people, you dows for Workgroups. Other what all the fuss is about. can easily trace your family concepts (e.g., artificial in- But if you've had any ex- back through three or four telligence) made small posure to Basic, C, Pascal, generations; if you're lucky, inroads, but remain on the FORTRAN, or most other pro- perhaps more. Corpora- back burner, waiting for a gramming languages, you tions are often structured good application. have to adjust your thinking. hierarchically. So is the mili- Another over -hyped yet And old timers, deeply im- tary. When we speak of the persistent (so to speak) idea mersed in traditional animal kingdom, we're is that of objects. Several procedural languages such really talking about a hier- years ago, you couldn't as COBOL, can have a archy. There are many open a magazine or trade really hard time. species of dogs, and cats. journal without being bom- Despite all of that, the Dogs and cats are both barded with object -this and concepts are not difficult. mammals. Mammals in-

object-oriented that. But This month I want to give cludes all dogs and all cats; then the Internet hap- you a basic sense of what it also includes human pened (that is, the general object technology is all beings, apes, bears, and so public became aware of it), about; next time, we'll look on. The list of examples and object lost its cachet. at things a bit more goes on and on. Byte magazine (in their May rigorously. Object technology (and

www.americanradiohistory.comAmericanRadioHistory.Com computer technology in enabies efficient computer Irish Setters, Bulldogs, and general, for that matter) processing. many more. depends heavily on the That is in marked contrast If you were going to de- concept of the hierarchy. to older, procedural ways of sign a new dog, you Developing object- oriented thinking about software. In wouldn't have to go all the software means building hi- those older ways, you nei- way back to hydrogen, oxy- erarchies. it means ther started out nor ended gen, and carbon. You could grouping like things to- up with something that di- start off with the group of gether -dogs with dogs, rectly corresponded to characteristics represented cats with cats-grouping anything in the real world. A by "dog" (e.g., walks on four One tree can make groups, groups of classic textbook is called legs, omnivorous, gives live grouping 3,000,000 matches. groups, etc. Talent in ob- Algorithms + Data Struc- birth, is domesticated), and ject- oriented software tures = Programs. The customize Just those fea- design and development thinking symbolized by that tures necessary for your involves the ability to rec- title shows a computer -cen- particular dog. ognize and create tric view of the world. By That is how object -ori- consistent patterns among contrast, the modern way ented software works. Take groups. of thinking is to model the an object, customize a few In the animal kingdom, a real world; that is, to repre- features to meet your dog is real, but higher levels sent it directly. needs, and that's it. Well, in the classification scheme One thing that makes ob- not quite. Things can and are abstract. One of the key jects so exciting is the ability do get complicated. But things about object -ori- to use the hierarchical the point is that object - One match can burn ented technology is that it structure to create varia- oriented technology starts 3,000,000 trees. follows the same idea. It tions on a theme. By and ends with the real starts with a real object (a analogy, the class "dogs" world. That fact alone gives document, an inventory list, includes Dalmatians, Sheep the software a higher a video clip, a scanned Dogs, German Shepherds, chance for success than photograph) and builds Scottish Terriers, Poodles, would otherwise be the 1,4 A Public Service of This Magazine around it a hierarchy that Chihuahuas, Dachshunds, case. & The Advertising Council

7e1 FULL- OR PART -TIME JOB /BUSINESS: al Whether you wish to save money, boldly go where no guitarist has gone Learn VCR repair! before or simply have fun building Career -level home study. high - for your s,. Master easy -to-learn, electronic gadgets designed profit repairs without buy- musical pleasure, then read ing costly, high -tech instruments. Free literature: send Electronic Projects for or call 24 hours a day. 800-223-4542 Gib =TAR Name Age Address Phone( ) Some of the add -on guitar gadgets you can build are: City State Zip $1295 The School of VCR Repair Road Distortion Effects Unit PCDI, 6065 Roswell Preamplifier Headphone Amplifier Soft Dc pt. VRC341 , Atlanta, Georgia 30328 Compressor Auto -waa Waa -waa Pedal Phaser Dual Tracking Effects Distortion Unit Expander Dynamic Treble Booster Direct Injection Box Dynamic Tremelo Thin Distortion Unit Be a computer and Guitar Tuner. repair expert! Anyone with some previous electronic project building experi- Career -level home study the projects. course. Learn all about PC re- ence should have no problem assembling pairs, troubleshooting, installation, upgrading, servicing. ELECTRONICS TECHNOLOGY TODAY INC. Open your own business; P.O. Box 240, Massapequa Park, NY 11762 -0240 become a more valuable em- ployee. For free literature: Yes, send my copy of ELECTRONIC PROJ- Please charge my Visa MasterCard send or call 24 hours a day. ECTS FOR GUITAR by RA Pentold to the Signature address at right. I am enclosing $12.95 plus 800 - 223 -4542 $2.95 for shipping charges in USA and Can- Account No. Expir. Date Nam, Age ada. All payments must be made in US Address Phone I funds. Sorry, no orders accepted outside of Name New York State residents USA and Canada. City State Zip add local sales tax.. Allow 6-8 weeks for Address delivery. The School of PC Repair 69 El Check enclosed. City State ZIP PCDI, 6065 Roswell Road L Dept. JJC341 Atlanta, Georgia 30328 www.americanradiohistory.comAmericanRadioHistory.Com CIRCUIT CIRCUS

By Charles D. Rakes I Ys show time, and are you troller circuit, see Fig. 1, uses latched until S2 is opened I ready for some circuitry two hexFET's and half of the and S1 is closed. Note that fun? Good! Make yourself inverters in a single IC to S2 must be opened before comfortable and get ready perform a simple two -func- the cycle is restarted via S1; to share a few electronic tion operation. The heart of as long as S2 is closed S1 control circuits. the controller circuit is a set will have no effect on the Over the last two de- and reset latch circuit circuit. cades, U.S. manufactures made up of two inverters. have steadily moved away When the input (pin 3) of FOUR -OUTPUT TIMER Controller from slow, and often unre- the U1 -a is grounded via S1, Our next controller, see liable, relay -control circuitry the output (pin 2) goes Fig. 2, offers up to four Circuits to the faster and more re- high, driving the input of timed outputs that can be liable microprocessor - inverter U1 -b high as well. used to operate motors, air based programmable con- That forces U1 -b's output valves, solenoids, relays, etc. trollers. The majority of low, latching the input of Two dual, retriggerable those programmable con- U1 -a low. In that latched monostable IC's and a few trollers were designed to be condition, the output of U1- support components are all placed in service by electri- c is high, turning on Q1 and that's required for the cir- cians who, in many cases, operating the motor. At the cuit. The timer sections are had little or no electronic same time, the low output cascaded so that as one training but were experi- of U1 -b keeps Q2 turned off. timer times out, it triggers The circuit remains in that the next timer, and so on state as long as switch S2 until the last timer times out. remains open. When the The intended application motor has completed its for the controller required a function, the stop switch, S2, two- sensor input that would can be manually closed. only start when both inputs That forces the input of in- occur simultaneously. Note, verter U1 -b low, and its however, that the start -sig- RZ U1-a output high which causes nal logic could be modified 1/64049 10K the output of U1 -c to go low, to accommodate a com- +6 -15V SOLENOID' turning off the motor. At the bination of any number of same time, the high at the input sensors, or even a output of U1 -b turns on Q2, single switch closure. The allowing a second load to controller also includes ar operate. Although that load inhibit circuit that keeps the is shown as a solenoid in sequence from re- starting the schematic, it could be before a cycle is com- *SEE TEXT a relay, another motor, etc. pleted. Fig. 1. This two function controller operates a motor when The circuit will remain Here's how it works. At rest, started, then energizes a solenoid, relay, etc. when stopped.

enced in relay -ladder logic. PARTS LIST FOR THE TWO- FUNCTION Since it's so easy to pro- CONTROLLER (Fig. 1) gram and use those controllers, many are used SEMICONDUCTORS to perform simple functions U1-4049 hex inverting buffer, integrated circuit that offen could be done QI, Q2- IRF511 hexFET transistor as well or better with a DI- 1N4002 silicon diode simple shop -built circuit. ADDITIONAL PARTS AND MATERIALS RI, R2-10,000-ohm, 5 %, 1/4-watt resistor TWO- FUNCTION SI, S2 -SPST switch CONTROLLER Motor (see text), solenoid (see text), wire, solder, etc. 70 Our first electronic con-

www.americanradiohistory.comAmericanRadioHistory.Com +6-15V As soon as U1 -a triggers R3 R6 1MEGz y R4 R7 and goes into its timing 1MEG 1MEG 'T 1 MEG 4 cycle, the Q output (pin 7) C4 C5 C1 goes low and the Q output tpf 1µF 1µF (pin 6) goes high; the Q H+ . + output is available at output 15 14 1 2 15 14 5 13 5 13 1. Those outputs remain in for the duration of 16 11 16 11 that state the timing period deter- 3 3 U1-a U1-b U2-a U2-b mined by R3 and C1. At the 1/24528 OUTPUT2 1/24528 OUTPUT 3 1/24528 OUTPUT 4 1/24528 OUTPUT 1 end of the timing period o Q 10 the outputs change state, 6 9 4 12 with the rising edge of the Q r Q output triggering the next timer, U1 -b, and so on. An inhibit function is provided by U5 -a. When each +6 -15V timer's Q output goes low, INPUT A is U5- 5 that low fed to one of 14 12 11 . 4 10 a's nputs. Whenever any of al 1/44011 +6-15V the inputs is low, the gate's R1 1 /44011 7 1K 1/44011 1/44011 output goes high, causing R5 the pin -9 input of U3 -b to 2.2K go low. When U3 -b is in that NY* sensor inputs are R2 2 state, the b 3C3 1/24012 1K unable to trigger U1 -a. To INPUT B 1/44011 17 30pF allow for pulse transition i time between timers, R5 Fig. 2. This four- output controller features an inhibit circuit built around U5 -a. and C3 add a slight time

PARTS LIST FOR THE FOUR- OUTPUT CONTROLLER (Fig. 2) BECOME AN

SEMICONDUCTORS ELECTRICIAN! U I. U2 -4528 dual reuiggerable monostable timer, integrated PROFESSIONAL -LEVEL HOME STUDY circuit U3, W 4011 quad 2 -input NAND gate, integrated circuit Train now to make U5-4012 dual 4 -input NAND gate, integrated circuit good money working on electrical RESISTORS systems in homes (All fixed resistors are %a -watt, 5% units) and businesses. RI. R2 -1.000 -ohm Learn all about R3, R4. R6, R7- 1- megohm. potentiometer how to wire, install, R5-2,200 -ohm resistor and maintain lighting, circuits, control ADDITIONAL PARTS AND MATERIALS panels, cables, ap- Cl, C2, C4, C5 -1 -iE 35 WVDC. electrolytic pliances, phone C3- 330 -pF, ceramic -disc systems, utilities, Wire, solder. etc. and much more. Fascinating, fun, and easy -to-follow. Learn at your own pace, in the corn - and before the cycle starts, and B. When both sensors fort of your home. For free litera- send or call 24 hours a day. the four inputs of U5 -a, one go high, the output of U3 -a ture, half of a 4012 dual -input goes low. Gate U3 -b inverts CALL 800 -223 -4542 passes the NAND gate, are all high. That that signal, and Name resulting high to the other produces a low output, Address which is passed to the in- input (pin 8) of U3 -c. When puts of U4 -a, 1/4 of a 4011 both inputs of U3 -c are City quad two -input NAND gate. high, the output of that de- State Zip As a result, the output of vice goes low. That input is Age Phan,. ( ) U4 -a is high; that high signal then inverted by U3 -d and is to is fed to one input (pin 9) of the resulting high used THE ELECTRICIAN SCHOOL U3 -c. Two sensors connect trigger the first sequential Dept. TEC341, 6065 Roswell Road 71 the circuits via inputs A timer, U1 -a. PCDI, Atlanta, Georgia 30328 to I.. CIRCLE 159 ON FREE INFORMATION CARD

www.americanradiohistory.comAmericanRadioHistory.Com 3 D1 N O 2 N D2 4 D3 3 O +6-15V 7 D4 4 IH O 10 D5 U1 N 4017 1 6 OUTPUTS N D6 o 5 D7 7 iH o 6 D8 8 9 D9 9 o 11 D10 10

14 13 15 IN914(10) g til&st

AN IMPORTANT PART +6 -15V OF YOUR PHOTOCOPIER R1 2.2K RESET ISN'T PART OF RUN O Ok YOUR PHOTOCOPIER Sib 11 /44011

6 U2-b Having a machine may not permit you to photocopy 2 R2 1/44041 1 books, journals, newsletters and magazines. 200K

The Copyright Clearance Center CAN. + c1 Contact us to find out how you too can COPY RIGHT!sM Fig. 3. Adjacent outputs of this 10 -step counter can be combined to produce longer on times. COPYRIGHT CLEARANCE CENTER 222 Rosewood Drive, Danvers, MA 01923 Tel. (508) 744-3350 Fax (508) 741-2318 © 1999 Copyright Clearance Center PARTS LIST FOR THE 10 -STEP COUNTER (Fig. 3)

SEMICONDUCTORS UI -4017 counter /divider, integrated circuit In the April 1995 Issue of U2 -4011 quad 2 -input NAND gate, integrated circuit DI-D10-1N914 silicon diode ADDITIONAL PARTS AND MATERIALS RI- 2,200 -ohm, %a -watt, 5% resistor Popular Electronics R2- 200,000 -ohm potentiometer C1- 4.7 -11,F, 16 WVDC, electrolytic capacitor Home Theater is hotter than ever. The editors SI -SPDT switch present basic to deluxe home -theater systems Wire, solder, etc. you can buy today and they provide in -depth reviews to guide your purchase. delay to the inhibit gate's produce Plus: longer timing peri- output. ods or, using diodes, the Build the Sprinkler Guardian: Give your garden If a longer on -time is de- outputs can be configured sired at or lawn the right amount of water. any stage, just to produce repeating increase the setting of the sequences. Buried Bytes -The History of the PC: Trace the appropriate timing potenti- A 4017 divide -by -10 coun- history of personal computers and computing ometer. Higher valued ter IC is the heart of this devices. capacitors and potentiom- simple ten -output controller eters (or even fixed resistors) circuit. Two gates of a 4011 Auto Electronic Stethoscope: An easy way to can also be substituted if quad 2 -input NAND gate IC hunt for sources of whines, rattles, squeaks, they are needed for a par- are connected in an asta- and other troublesome automotive noises. ticular application. ble oscillator circuit to clock the divide -by -10 counter, U1. TEN -STEP On Sale February 16, 1995 TIMER The step time is set by R5. Our last circuit, see Fig. 3, With the run /reset switch in Pick up Popular Electronics at your operates in a sequential the run position, U1 takes favorite Newsstand, Bookstore, ten -step mode with each of ten equal steps and then the timing periods being stops. Momentarily switch- Supermarket or Convenience Store equal. Adjacent outputs ing S1 to reset starts the 72 can be tied together to cycle over.

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www.americanradiohistory.comAmericanRadioHistory.Com DX LISTENING

By Don Jensen hortwave is, of course, that, and it wasn't until the neering. The shortwave the classic, and oldest, mid- 1950's that Austria be- service airs programs in means of international gan planning and German, English, French, broadcasting. In the late preparing for a major short- Spanish, Arabic, and the in- 1920's, a number of nations wave- broadcasting center. ternational Esperanto began experimental trans- Then, in 1959, a foreign language. missions on the SW shortwave service began The station's daily "Report Shortwave frequencies, In central Eu- operating at Moosbrun, from Austria" program in- rope, Austria was one of some 25 kilometers south- cludes world, European, from Austria those shortwave pioneers. east of the Austrian capital, and Austrian news, and re- Vienna. ports on political develop- Today, there are a pair of ments, economics, the arts, high -powered 500/300 -kilo- current affairs, and sports. watt transmitters, plus two Austrian music adds an un- 100 -kilowatt units, operating mistakable flavor to the from Moosbrun. With various station's SW programming. directional broadcasts, The program segments sometimes operating in aimed at North America parallel in more than one are aired at 0130 UTC on language, Radio Oesterich 9,655 kHz; at 0530 and International (Radio Austria 0630 UTC, relayed from International) transmits Canada, on 6,015 kHz; and more than 80 hours of pro- at 1130 UTC on 13,730 kHz. gramming a day. In addition, English transmis- Since March 1989, some sions beamed to South programs directed to North America can be received America are sent via satel- in the U.S. at 0130 UTC on lite to Radio Canada 9,870 and 13,730 kHz. International's transmitter For SWL's who want to facility at Sackville, New write Radio Austria Interna- Brunswick, for relay. In return, tional, the address is the Austrian transmitters are Wurzburggasse 30, Vienna used to relay some of RCI's A -1136, Austria. shortwave broadcasts. In addition, English program- IN THE MAILBOX ming of Radio Austria James Wright, Houston, International can be re- TX, writes with several ques- ceived in the United States tions. on the C -Span audio net- "Will there ever be a work. shortwave -radio station in Since it began broad- the state of Oklahoma? casting to overseas Seems like there would be This is part of Radio Austria International's elaborate shortwave - audiences, the Austrian in Tulsa, for Oral Roberts. antenna system at Moosbrun. broadcaster has gained in "What about Radio Aus-

importance. Production tralia? I never hear them As early as 1929, experi- and studio facilities are lo- anymore. And how about mental programming was cated in the ORF Center in Hawaii? Why isn't there any being aired by that country. Vienna, where six well - SW station there" In those days, - high equipped studios are used I can't say for sure, Jim, if powered transmitters were for producing programs. there will ever be a short- not available, nor, in those Radio Austria International wave broadcaster in times of relatively little inter- has about 100 staff mem- Oklahoma. I've heard of no ference from other stations, bers and freelance plans by the Oral Roberts were they needed to reach employees providing lan- organization to establish a listeners overseas. guage service, station. Right now religious 76 World War II ended all of administration, and engi- groups have no difficulty

www.americanradiohistory.comAmericanRadioHistory.Com ATTENTION! buying air time on existing Parkway, Reynoldsburg, OH U.S. shortwave stations. 43068); Easy Shortwave An- It shouldn't be too difficult tennas, by Frank Hughes CTi to hear Radio Australia. You ($9.95 + $2 S&H, Tiare Pub- indicated that you listen lications, PO. Box 493, Lake CHN mostly during the evening Geneva, WI 53147); and 1 hours. Try these Radio Aus- Limited Space Shortwave EARN YOUR ` tralia channels: 17,795 and Antenna Solutions, by Frank ) 17,860 kHz, at 0030 to 0600 Hughes ($10.95 + $2 S&H, B.S.E.E. UTC; 9,860 and 11,910 kHz, Tiare Publications). at 0630 to 0730 UTC. You should find the an- DEGREE Finally, Jim, there is now a swer to your antenna THROUGH HOME STUDY station, problem in one or more of Hawaiian shortwave Our New and Highly Effective Advanced- Place- KWHR, World Harvest Radio, those books, Oscar. Cata- ment Program for experienced Electronic Tech- nicians grants credit for previous Schooling and Its is: logs describing those and at Naalehu. schedule Professional Experience, and can greatly re- 0000 UTC on 17,555 kHz; other shortwave- related ti- duce the time required to complete Program and graduation. No residence schooling re- 17,510 kHz; tles are available from the reach 0200 UTC on quired for qualified Electronic Technicians. 0600 UTC on 9,930 kHz; firms mentioned above. Through this Special Program you can pull all of the loose ends of your electronics background 1600 UTC on 7,425 kHz; 1800 together and earn your B.S.E.E. Degree. Up- UTC on 13,625 kHz; 2000 DOWN THE DIAL grade your status and pay to the Engineering Level. Advance Rapidly! Many finish in 12 UTC on 13,720 kHz; and Your shortwave loggings, months or less. Students and graduates in a 50 2200 UTC on 17,510 kHz. with times, frequencies, and States and throughout the World. Established A letter from Oscar Naimi program descriptions, are Over 40 Years! Write for free Descriptive Lit- erature. of Mukilteo, WA asks about wanted. Drop me a line at shortwave receiving anten- DX Listening, Popular Elec- INSTITUTE nas. "I'm not using a serious tronics, 500 -B Bi- County COOK'S OF ELECTRONICS ENGINEERING antenna at the present Blvd., Farmingdale, NY time, just my bed frame (It 11735.. CE 4251 CYPRESS DRIVE E JACKSON, MISSISSIPPI 39212 may sound funny, but ifs ok). Here are some SW like hear about sug- catches recently reported I'd to CIRCLE 14 CN FREE INFORMATION CARD gestions on how to improve by listeners. my antenna ?" CONGO-4,765 kHz. Your bed may function as Radio Congo has been Make an "ok" antenna, Oscar, but noted in French around you'll wake up your SW re- 0515 UTC with identification, U.S. Savings Bonds ception with a decent African music, and rhythmic skywire. Fortunately there drums, followed by a news- part of your are a number of good ref- cast. The station operates in erence books on SW parallel on 5,985 kHz. retirement savings antennas. Here are a few HUNGARY-9,835 kHz. program. titles available: Radio Budapest is heard Receiving Antenna Hand- with Hungarian ethnic mu- book, by Joseph J. Carr sic at around 0220 UTC. ($19.95 + $2.50 S&H, Grove After an interval signal of Enterprises, PO. Box 98, trumpets and station identi- Brasstown, NC 28902); The fication, English Antenna Handbook, by programming begins at Clem Small ($12.95 + $2.50 0300 UTC. They're the safe, easy and affordable S&H, Grove Enterprises); The INDIA- 13,750 kHz. All In- way to save for retirement. Buy U.S. Easy Wire Antenna Hand- dia Radio is reported here for as little as $25. Ask with Indian music at 0020 Savings Bonds book, by Dave Ingram your banker or your employer about UTC. That is followed by ($9.95 + $1 S&H, Universal including U.S. Savings Bonds in your Radio, 6830 Americana English news. retirement savings program. PARAGUAY -9,735 kHz. For more information, write Radio Nacional de Para- Washington, DC 'CREDITS: Brian Alexander, U.S. Savings Bonds, guay broadcasts from one message of PA; Marie Lamb, NY; Harold 20226. For a recorded Levison, PA; John MacDonald, of the more difficult to log current rate information, call WA; William McGuire, MD; South American countries. I -800 -4US BOND : -800- 487 -2663 David Morasco, WV; Ed New- Try for it at around 2230 NE; Betsy Robinson, TN; bury, UTC. It has been noted in North American SW Associa- futbol news Take,..rÌ T (SAVINGS tion, 45 Wildflower Road, Spanish with StockL. / ` 77 Levittown, PA 19057. and Paraguayan music. inAmerica . ICJ .BONDS A public service of this magazine

www.americanradiohistory.comAmericanRadioHistory.Com HAM RADIO

By Joseph J. Carr, K4IPV Antennas are near and the output of his transceiver bands: On 3.5 -4.0 MHz, the dear to the hearts of and the feedline to the antenna works as a slightly ham operators and more G5RV; as we will see, that's folded, foreshortened di- advanced shortwave lis- a critical mistake. pole. On 7 -7.3 MHz, it acts teners. This month we will Although the dimensions as two half -wave radiators take a look at a couple of of the G5RV have been fed in- phase. On 10 MHz, antenna topics, including subject to some controversy, the antenna acts as a col- an antenna project. for the high- frequency (hf) linear antenna with two in- ham bands (80-10 meters) phase half -wave radiators THE GSRV ANTENNA the G5RV dimensions have (but its load is more reac- The G5RV antenna was been pretty well- estab- tive than on 7 MHz). On 14 designed several years ago lished by experiment and MHz, the G5RV acts like a Some by Louis (G5RV), Varney a trade -off. As shown in Fig. 1, 3/2- wavelength dipole (i.e ham operator in the United the two horizontal radiator like using a 40 -meter dipole Antenna Kingdom. The G5RV anten- elements are 52 feet long, on 15 meters). At 18 MHz, na is not terribly popular Topics in or a total of 104 feet overall. the antenna is Iwo full -wave the U.S., but if you read the The length of the matching radiators fed in- phase. On ham magazines from Eu- section depends on which 21 MHz, the antenna acts rope, you'll find it's that type of transmission line is like a 1/2- wavelength long - much more common "over used: If you prefer 450- to wire antenna. Finally, on there." 600 -ohm parallel open -line 28 -29.7 MHz, the G5RV acts feeders, the length is 34 like a 1/2- wavelength long- A feet; if you prefer 450 -ohm wire antenna, but with a twin -lead, the length is 28 much lower feedpoint im- feet; and if you prefer 300 - pedance than on 21 MHz. ohm twin -lead, the length is Because of those dif- RADIATOR 27 feet. ferences in operation, the The G5RV antenna is fed G5RV antenna will have a by 75 -ohm coaxial cable, different feedpoint imped- although the feedpoint im- ance at different fre- MATCHING SECTION pedance can vary quite a quencies. Again, that's why bit from 75 ohms. That's the an ATU is a must! reason why an antenna - tuning unit is needed! RECEIVE OR TRANSMIT The G5RV is built much ANTENNAS? 75(1 COAX TO 104FEET like a dipole, using the A- RANSCEIVER One of the attributes of B . 34 FEET (OPEN -WIRE LINE) same kind of wire and in- radio antennas is the prop- - 28 FEET (450a LINE) sulators. The rope supports erty of reciprocity. That 27 FEET (300(1 LINE) (R), at either end, are con- means antennas work the R . ROPE SUPPORT nected to standard end same El . END INSULATOR on receive as they do insulators (El), which are on transmit. In other words, Fig. 1. The G5RV antenna is an interesting multiband ham available at most radio - the azimuth pattern of a antenna, but an antenna- tuning unit is a must for good results. supply stores. The center in- half -wavelength dipole is sulator can be another end the same on both transmit I've known several hams insulator (which will work and receive. who've used the G5RV and well), or it can be a special Reciprocity is a fact of life I've used one myself. The center insulator. Make sure on antennas. Attempts to results are mixed, and I sus- that the center insulator is prove cases of non -re- pect the difference is in not actually a BALUN trans- ciprocal antennas have, how well the design is im- former. While the BALUN is thus far, always been based plemented. It is significant, used extensively for dipole on a false premise or two. for example, that one chap antennas, it is not appropri- For example, one fellow at- who claimed the G5RV did ate with the G5RV tempted to prove that not work well failed to use The G5RV works dif- antennas are not re- 78 an antenna tuner between ferently on different hf ciprocal on the hf bands

www.americanradiohistory.comAmericanRadioHistory.Com because there are For best results, the antenna ionospheric conditions that should be oriented so that are not bidirectional. the deep side nulls point in It is a well -known phe- the direction of the un- nomenon that sometimes, desired signal. While we especially in the late after- don't pick -up the desired noon or evening on 40- signal as strongly as we meters, European stations might if the maximum sig- are heard in the U.S., par- nal line was aligned with ticularly on the east coast; the signal, the ratio of the but we cannot be heard by MAXIMUM RECEPTION LINE desired to undesired signal them. That is due to anom- is maximized. alies in the ionosphere that While it is true that most causes propagation in one ham antennas are useful direction to be different on both receive and trans- from propagation in the mit, that is not always the opposite direction. That dif- case. I've seen situations on ference is not a failure of DESIRED SIGNAL ANTENNA the crowded 75/80- and antenna reciprocity, but an Fig. 2. For best results, a half-wave dipole should be oriented so 40 -meter bands where a indication that the that its deep side nulls point in the direction of an unwanted dipole was used as the ionosphere sometimes isn't signal transmitting antenna and a the same in both directions. rotatable small -loop anten- Another argument ideal transmit anten- shortwave and ham -band na was used as the receive against antenna reciprocity na should be designed to receivers. With only 0.1 to antenna. The loop has an is the operation of the Bev- maximize the gain in the 0.5 µV needed to produce azimuth pattern similar to erage antenna. The direction in which one wish- a 10 -dB signal -to -noise that of Fig. 2, but the axis is Beverage is a receive an- es to transmit. That way, we ratio, most receivers don't opposite (the nulls are tenna that works best on can take advantage of the have to worry too much broadside to the antenna, the lower frequencies. The inherent gain of the anten- about getting enough sig- not off the ends as in the Beverage works best over a na for 'free" power or nal. Of far greater dipole). poor ground, except at the signal strength. For exam- importance is the signal -to- Another example is the end far from the feedpoint. ple, if the antenna has a noise ratio (SNR) of the re- case of using a vertical The best Beverage antenna gain of 8 dB over a dipole ceiver system. antenna on transmit and a is said to be one that is (as is claimed for many 3- The SNR should typically loop or dipole on receive. largely over desert or element beams), then a be 10 dB for comfortable I've known one ham who beach (which is a poor 1,000 -watt transmitter will listening, although skilled had a 40 -meter vertical ground), with the termina- have the same signal operators can detect signal plus two 40 -meter dipoles tion resistor at the far end strength at a distant point with a considerably worse at right angles to each grounded in a brackish or as a 6,300 -watt signal fed SNR. In the case of the other. He could select any salt -water swamp! The to a standard half -wave- receiver system, the SNR in- of the three antennas for claim for non -reciprocity re- length dipole. cludes not just internal either transmit or receive, sults from the fact that the Another advantage of white noise "hiss," electrical as needed. If transmitting Beverage is a very ineffi- using an antenna with gain noise, and lightning static east -west, for example, he cient antenna, so it is not a for transmitting is that it pro- (snaps, crackles, and pops), might use the east -west di- good choice for transmit- tects stations off-axis. In but also undesired stations pole for the transmitter, and ting. However, the patterns other words, while gaining on the same or adjacent the north -south one for the and impedances, and all a few dB of signal strength channels. When you are try- receiver. Similarly, if transmit- other elements on which in the direction of interest, ing to copy a station ting on the vertical, for we characterize an anten- you also keep others from through lots of co- channel receive he selected which- na, are the same for both being clobbered by your or adjacent channel QRM ever dipole reduced the receive and transmit for the signal in directions that are (man -made interference, interference the most. Beverage. of no interest. That's good typically other stations), Fortunately, some trans- That brings up another spectrum management, those QRM'ing stations are ceivers allow separate issue: Is it true that the best and good manners. pure noise. receive and transmit anten- receive antenna is also the The receiver antenna, on In the case of a receiver nas. If yours does, it will best transmit antenna? Re- the other hand, might have system, a good antenna have a second rear-panel ciprocity would seem to say different goals than the might be one that has SO -239 connector marked so, but that's a false notion. transmitting antenna. Sure, sharp nulls or notches, such for a receive antenna. Oth- Why? The attributes of a we can use the gain of the as a half-wave dipole (see erwise, you will need to good receive antenna are antenna to boost received Fig. 2). Consider two signals, build some type of system not the same as those of a signals. But that is not usu- one the desired signal and to switch between two an- good transmit antenna. ally a problem with modern one the interfering signal. tennas. 81

www.americanradiohistory.comAmericanRadioHistory.Com SCANNER SCENE

By Marc Saxon ere's an exciting way to to do is provide the scan- low complex store, search, Li expand the caner. The software is the OEM and scan features to be pabilities of the already version of ScanStar, which easily accessed. excellent Realistic PRO -2005 supports tone, code, and The complete OptoScan and PRO -2006 scanners. It's touchpad character de- 456 installation kit includes a product called the coding as well as received the assembled and tested OptoScan 456 system, signal level. The power of controller board, mounting which includes hardware the OptoScan 456 is real- hardware, cables, software, and software for full com- ized by the scanning and installation manual. It puter control of all software used. The profes- costs $299. For more infor- scanning functions. In addi- sional versions of the mation, write to Opto- PC- Powerful tion, unlike all other radios, ScanCat and Scan "Star electronics Inc. at 5821 N.E. the OptoScan 456 includes software both support 14th Avenue, Ft. Lauderdale, Scanning CTCSS ("PL tone "), DCS OptoScan 456 with up- FL 33334, or call code, and DTMF (tele- graded features, such as a 1- 800 -327 -5912 or phone touchpad) char- spectrum display. Windows - 305 -771 -2050. acter reading, integrated based and Mac software with the software scan and are under development by LOOK, UP IN THE SKY! log functions. independent organizations. Readers often ask if it's The OptoScan 456 inter- possible to tune in directly face assembly can be to the space shuttle. and installed in your scanner several times we have pro- without cutting, drilling, or vided amateur radio, two - soldering. It's done with de- meter band frequencies tachable cables, which are that have been used. That provided. The installation isn't the only way, however! manual uses photos and For quite some time now, step -by -step instructions. scanner owners have been The entire installation advised that the space should take the average shuttle also has a (alter- scanner owner about two nately reported AM or FM) hours using simple hand "primary" frequency of tools. 296.8 MHz, and a "second- With the OptoScan 456 ary" frequency of 259.7 on the job, the scanner MHz. Those channels are, of Put the u PC PRO or PRO with power of behind your -2005 -2006 operates at high speed (50 course, in addition to the the OptoScan 456 interface system from Optoelectronics. channels per second) and shuttle's main communica- has nearly unlimited mem- tions system, which The hardware can sense ory. Even when you're not operates at 2 GHz in a when a computer interface there, your scanner can digital mode. is established. It then places continue to search out Actual use of the 200 - the scanner's micro- those frequencies that you MHz band by the space processor into stand -by want to check out, and can shuttle has been doubted, mode. Control over all ra- record them into a virtually or at least questioned, by dio functions passes on to unlimited number of mem- some monitors. Shall we say the computer. A cable is ory channels. It relentlessly that reports of reception provided for direct RS -232C pursues and searches for have not been abundant/ interface with a computer's elusive or infrequently used We say, keep on listening!

serial port. channels. The software I personally can attest to Custom OptoScan 456 in- makes scanning easier recent activity there. When troductory software for the than the radio's front-panel astronauts Mark Lee and 82 PC is provided. All you have controls. Software menus al- Carl Meade took their Ex-

www.americanradiohistory.comAmericanRadioHistory.Com travehicular Activity (EVA) Gateway downlinks from space walk from the Discov- 400.15 through 401.00 MHz.

I r^ ery last September, was able to directly monitor IN THE MIX "NEW BOOKS" their communications on Eugene W. McLees, of 259.7 MHz, in AM mode, as Madison, Connecticut, re- for the Project Builder the craft was passing over ports that his local police my area. operate on 453.475 MHz, BP350- ELECTRONIC BOARD That reception was ac- but complains that they GAMES $6.00 complished using a scramble some of their Twenty novel electronic board games PRO -2006 with a GRE transmissions. That is a that you can build from the plans in this Superamplifier hooked up grumble heard from read- book. Whether you are interested in motor racing, searching for buried trea- to a MAX -225 UHF military ers in other areas, all of sure on a desert island or for gold in Fort aeronautics -band ground - whom want to know if there Knox, spinning the wheel of fortune, or plane antenna. Signals is a scanner accessory doing a musical quiz -there is some- that will descram- came through quite well, available thing for you to build and enjoy! and were undoubtedly via ble and copy the on transmissions. an on -board repeater PCP119- ELECTRONIC MUSIC There was one, until the shuttle. The space suits AND MIDI PROJECTS $14.95 transmit on 279.0 MHz, about eight years ago, Save cash by building the MIDI gadgets which must be the input for when the government you need. Want a MIDI THRU box, pro- that repeater. Even so, the forced the little gizmos off gram change pedal,. Metronome, analog transmitter on 259.7 MHz the market. Most police de- echo unit, MIDI patchbay or switcher? probably wasn't running partments use a rather Over 16 practical and very useful music much power. simple but effective form of and MIDI projects -all in this book! The in detail with full Keep 296.8 and 259.7 analog scrambling. Analog projects are explained instructions on assembly. MHz, AM mode, plugged in scramblers are easy to during space shuttle mis- crack. It's the same system BP301- ANTENNAS FOR VHF sions. They are active used in today's 46 -MHz n AND UHF $6.00 cordless phones. Some Antennas for frequencies, and good VHF and UHF From installing a TV or FM antenna to clever "techie" might figure ones. setting up a multi- antenna array for out how to adapt an ana- shortwave listening or amateur radio, ALSO GOING UP log- scrambled phone as a this book explains the basics of VHF and An interesting new satel- scanner accessory. UHF antenna operation and installation. lite system will be using Analog scanning is vastly The text describes in easy -to- understand frequencies within the different from the digital terms the essential information about range of scanners. Leo One scanning used in 900 -MHz how antennas works, the advantages of types, and how to get will have 48 low orbit (513 cordless phones and in the different antenna the best performance from an antenna. miles high) satellites circling more sophisticated the globe, with 12 satellites scramblers used by some Inc. in each of four circular or- federal- agency communi- Mail to: Electronic Technology Today, NY 11762 -0240 bits. The satellites will be cations systems. Digital P.O. Box 240 Massapequa Park, designed to support a vari- scrambling sounds like a Shipping Charges in USA & Canada ety of subscriber applica- hiss on a scanner. Thus far, it $0.01 to $5.00 $1.50 $30.01 to $40.00 $5.50 tions, including status has never been possible for $5.01 to $10.00 $2.50 $40.01 to $50.00 $6.50 monitoring, vehicle track- scanner owners to de- $10.01 to $20.00 $3.50 $50.01 and above $8.00 ing, paging, E -mail, security scramble digital scramblers. $20.01 to $30.00 $4.50 monitoring and control, An anonymous reader in Sorry, no orders accepted outside of USA and Canada. All emergency alerting, etc. Ohio passed along the payments must be in U.S. funds only. Leo One will provide store - Cuyhoga Falls trunked sys- Number of books ordered. and- forward data services. tem in use for the past year. Total price of books $ Service is set to com- Police /Fire primary is mence within two years. 855.1625 MHz, with the sec- Shipping (see chart) $ The satellites will have com- ondary being 854.1625 Subtotal $ munications links with one MHz. Control or city services Sales Tax (NYS only) $ another in the Ka -band (22 can be found on 853.1625 Total enclosed $ and 24 GHZ), thus offering MHz, control or fire depart- Name ment on 852.1625, and city worldwide coverage. Address Uplinks are all from 148.00 services or fire department City State ZIP to 150.05 MHz. Transceiver on 851.3625 MHz. downlinks are from 137.00 That's all for now. See you Please allow 6 -8 weeks for delivery. II=M =MI to 138.00 MHz, with again next month. - R M -

www.americanradiohistory.comAmericanRadioHistory.Com ELECTRONICS LIBRARY

Hackers cannot live by comput- includes pointers for guarding

ers alone -some physical your keyboard from dip spills, Rtrt IRONIC PROM I UI.Lt. x.. sustenance is required as well. preventing soggy chips, and \\I) FUME( WON According to the author of this cleaning your screen. 1,,01,1, lirin ,.. cookbook, food is often the only Giga Bites: The Hacker interruption tolerated by the Cookbook costs $9.95 and is dedicated (read: fanatical) published by Ten Speed Press, hacker. Whether devoured over P.O. Box 7123, Berkeley, CA the keyboard or during a short 94707; Tel. 800-841 -2665 for Giga Bites: break, the hallmarks of hacker orders or 510 -559 -1600; cuisine (also known as Fax: 510-524 -4588. The Hacker "cyberchow" or "technogrub ") CIRCLE 80 ON FREE are large portions, quick prep INFORMATION CARD Cookbook time, and unpredictable results. Although nutritional content is 17th Edition not a priority, none of the recipes in this book contain more ELECTRONIC PROJECT by Jenz Johnson than 6000 calories per serv- DESIGN AND Part Ill is devoted to actual ing-a real achievement when FABRICATION; Third construction projects. It dealing with such culinary treats covers Edition concepts, documentation, sys- as "Twinkie Casserole," "Left- by Ronald A. Reis tem diagrams, circuit design sketching, and packaging plans This book provides the real -life for 15 insertion mount tech- TOT OFFICIAL 1116( TO !MIR COMM( experience in project design, nology (IMT) projects. building, and documentation Electronic Project Design and that every hobbyist and pro- Fabrication, Third Edition, costs spective electronics technician $45.00 and is published by needs. It opens with a step -by- Prentice Hall, Inc., Englewood step guide through the pro- Cliffs, NJ 07632. totype project design and CIRCLE 99 ON FREE fabrication process for the INFORMATION CARD "sample project " -a variable power supply -and the "exer- cise project " -a three -channel THE VIRTUAL REALITY color organ. Fifteen elective PROGRAMMER'S KIT projects, including an audible by Joe Gradecki logic probe, a digital temperature controller, a push -button This book -and -software pack- combination lock, and a burglar age provides everything that the alarm, are also presented in the computer user with no program- book's first section, which con- ming experience needs to cludes with an introduction to produce virtual reality (VR) pro- computer -aided design. grams- including virtual cities In Part II, project design and populated with animated peo- fabrication using surface -mount ple, robots, or bizarre technology is covered in three monsters-on his or her own chapters. An overview of the PC. Readers who have a little subject is followed by hands -on knowledge of the C program- over Chinese Food Dip," and study of SMT component ac- ming language will also learn to "Hacker Fondue with Pork quisition, circuit breadboarding, create multi -user worlds that Rinds." The microwave is the surface -mount PC -board de- work over modems; design lab- appliance of choice, and favorite sign, and SMT project assembly yrinths and VR games with ingredients include Cheez Whiz, using traditional hand tools. The sophisticated animation and 3D Wonder Bread (usually squash- third chapter explores the tools sound; and integrate projects ed into bread balls), Spam, and and techniques needed to re- from a companion book, The anything that comes in a can. work commercial products Virtual Reality Construction Kit, 84 Along with recipes, the book involving surface -mount circuits. into original virtual worlds.

www.americanradiohistory.comAmericanRadioHistory.Com amateur radio today and into dBASE programs using dBASE the future. for Windows unique two -way The book is aimed at amateur tools. An in -depth index in- radio operators, broadcast engi- cludes advanced administration Virtua neers, electronic hobbyists and and management information. Reality professionals, science teachers The companion disk features and students, and anyone inter- a tutorial software system that PROGRAMMERS KIT ested in communications illustrates key techniques and A empiric sel of reek lee erennen leur one features in programming. All of newel norlds technology. It features chapters on radio and communications theory, background information on assembling, setting up, and testing an amateur radio station; and a wealth of new projects for the home builder, from power supplies to transceivers and 1995 Technical Supplies amplifiers. the The The package also offers tips Fxtoeul to Catalog is free upon request for experienced C program- The 1995 ARRL Handbook Canmamon Wisdoms from HMC, 33 Springdale mers, providing code to add for Radio Amateurs costs $30 Detainee Management Avenue, Canton, MA 02021; advanced features to their crea- and is published by The Ameri- Prevalent) Tel. 617 -821 -1870; tions. The four complete virtual- can Radio Relay League, 225 Fax: -821 -4133. reality applications included on Main Street, Newington. CT 617 CIRCLE 84 ON FREE the disk can be explored as is 06111; Tel. 203 -666 -1541; INFORMATION CARD or customized for unique VR Fax: 203- 665 -7531. experiences. CIRCLE 82 ON FREE INFORMATION CARD The Virtual Reality Program- the tables, queries, forms, re- mer's Kit costs $29.95 and is ports, and programs needed for SIMPLIFIED DESIGN OF published by John Wiley & working with the examples in LINEAR POWER Sons, Inc., Professional Refer- THE VISUAL GUIDE TO the book are on the disk, linked SUPPLIES ence and Trade Group, 605 dBASE FOR WINDOWS through a convenient menu by John D. Lenk Third Avenue, New York, NY by Carl Townsend system. 10158 -0012. The Visual Guide to dBASE This one -stop guide to linear CIRCLE 88 ON FREE With tips for developers and for Windows book with disk power -supply design is well suit- INFORMATION CARD and designers at all levels, this costs $29.95 and is published ed for beginners, students, book -and -disk package offers a by Ventana Press, P. 0. Box experimenters, as well as de- comprehensive examination of 2468, Chapel Hill, NC 27515; sign professionals. It feature and di- 1995 ARRL HANDBOOK effective, efficient database de- Tel. 919 -942-0220; step -by -step instructions requires no FOR RADIO AMATEURS sign for dBASE users. It Fax: 919 -942-1140. agrams, and CIRCLE 83 ON FREE previous design experience. from The American Radio Relay provices a generously illus- INFORMATION CARD The book concentrates on the League trated overview of dBASE for Windows, including version 5's use of commercial IC regulators by discussing the selection of The 72nd edition of this au- fresh new interface and OOP external components that modi- thoritative handbook is not language extensions. 1995 TECHNICAL fy the IC- package character- merely a revision but an entirely The book defines dBASE SUPPLIES CATALOG istics. A full chapter is devoted rewritten book that supersedes basics, such as exploring the from Hub Material Company to heat sinks and other temper- all previous editions. It has been Navigator, Catalog window, (HMC) ature- related design problems. reorganized for easier reading Command window, tables, Another chapter covers testing and represents several years of forms, and queries. It explains HMC's full -line 1995 catalog is the linear supplies in both ex- research and revision. New sec- how to design dBASE filled with the electronic tools, perimental and final form, and tions cover digital signal databases, from analyzing your test gear, and technical supplies illustrates the connections of the processing and other evolving goals and needs, to using required for the assembly, test- completed supplies. technologies that are shaping sound design concepts and ing, and repair of electronic fully techniques, to working with ob- products. The detailed buying Operation of all circuits is foundation jects. The book provides hands - guide features a broad selection detailed to provide a totally un- on practice in creating and mod- of brand -name items at compet- for those who are ifying tables, organizing and itive prices, complete with large familiar with linear supplies and All moving data, indexing informa- photographs, clear copy, and a refresher for professionals. tion, and correcting problems. comparison tables of product popular forms of linear supplies, The book also explains how features. The catalog includes including zener, three -terminal, foldback, op- to design, create, and execute test instruments, tool kits, sol- feedback, current queries; create fast forms with dering /desoldering systems, amp, series, shunt, and IC in detail. the Form Expert; customize precision hand tools, work sta- package, are covered with the Form Designer and tions, industrial chemicals and In addition, the design exam- Crystal Reports; and use adhesives, data communica- ples can be put to immediate modified to SpeedMenus and the Menu De- tions and telecommunications use as is, or can be signer to add menus, buttons, equipment, PC -board handling meet a specific design goal. Linear and SpeedBars. Finally, it equipment, and static -control Simplified Design of shows readers how to develop products. Power Supplies costs $29.95 85

www.americanradiohistory.comAmericanRadioHistory.Com and is published by Butterworth Besides the games people The Master Catalog buy a Pentium -based PC in- Heinemann, 313 Washington play online, the book also 1994 -1995 is free upon request stead of building one. Street, Newton, MA covers the thousands of free from Jensen Tools Inc., 7815 Build Your Own Pentium Pro- 02158 -1626; Tel. 617- 928-2500; computer games and demos South 46th Street, Phoenix, AZ cessor PC costs $19.95 and is Fax: 617- 928 -2620. that can be downloaded from 85044; Tel. 800 -426-1195. published by Tab Books Inc., CIRCLE 85 ON FREE online archives. It describes the CIRCLE 87 ON FREE Blue Ridge Summit, PA INFORMATION CARD clubs that share cheats, hints, INFORMATION CARD 17294 -0850; and walk -throughs for mastering Tel. 1- 800-233 -1128. home NET GAMES: Your Guide and arcade hits ranging CIRCLE 98 ON FREE to the Games People from Mortal Kombat to NBA BUILD YOUR OWN INFORMATION CARD Play on the Electronic Jam (and even the daily PENTIUM' Highway crossword puzzle). PROCESSOR PC Net Games: Your Guide to by Aubrey Pilgrim MINIATURE SATELLITE by Kelly Maloni, Derek Baker, the Games People Play on the DISHES: and Nathaniel Wice Electronic Highway costs $19 If you dream of owning a power- The New Digital and is published by Random ful new Pentium -processor PC, Television By some estimates, more than House Electronic Publishing/ but can't afford to buy one at by Dr. Frank Baylin half of online time is spent Michael Wolff & Company, Inc.; today's prices, this book is for playing interactive games. At Tel. 1- 800 -NET -1133. you. Although a Pentium -based Digital broadcasts from high - any hour of the day, millions of CIRCLE 86 ON FREE computer is much more power- power satellites to 18 -inch dish- INFORMATION CARD people worldwide are online ful and expensive than most es are now being transmitted, playing games with each other other commercial PC's, it isn't and this book covers all aspects in Cyberspace, where online ca- MASTER CATALOG more difficult to assemble. This of the new direct broadcast sat- maraderie and competition rival 1994-1995 book explains how to construct ellite (DBS) industry, including the intensity of contact sports. from Jensen Tools an IBM- compatible Pentium the technology, the players, and The new breed of games takes computer out of mail -order parts the programming, as well as advantage of the Internet and Jensen's latest catalog has and peripherals for a fraction of signal security and installation other computer networks to been upgraded with larger dealer prices. methods. bring human rivalry and team pages, pictures, and type, to After an overview of the Pen- The book opens with an over- spirit directly to your screen. make it easier to use. The tium processor and its view of DBS and also covers This book is a guide to more catalog offers a single source of capabilities, the book describes the underlying technology of than 1500 of those new comput- tools and test instruments for satellites and receiver systems. the installation and mainte- Topics such as digital video compression, bit error rate, re- Wtnc flaying m lÿbnrspaect Find Out In... nance of electronic equipment and systems. It features a full ceiver design, and compatibility line of specialty tool kits and of large- and small -dish sys- cases, as well as the latest tems are studied. Next, the DBS portable field -test equipment Pentium players -DirecTv, EchoStar, Your (;Hide to the PrimeStar, from major manufacturers. Also PIDCESSOT and USSB -are dis- 1111 included are hard -to -find tools, cussed, along with their . on the Electronic PC satellites and systems. The Highway f. book examines how DBS differs from large -dish satellite TV and cable TV, the origins of DBS, and DBS frequency allocations. SAME 'BUNDLE Subsequent chapters outline the encryption systems used for signal security and examine the er games. It includes multi - in step -by -step, illustrated detail program packages and player virtual scrimmages such how to put together all the prices offered by various as Air Warrior, Cyberstrike, necessary components, includ- players. The step -by -step procedures for Doom, and Bolo, which corn - ing motherboards, floppy and installing both small- and large - bine the local color of a home- hard drives, CD -ROM drives, dish satellite systems town bowling league with the printers, input devices, memory are presented in detail. The final massive firepower of a Hol- chips, monitors, graphics cards, chapter demonstrates the meth- lywood action movie. Traditional fax/modems, and backup sys- ods used to hook up and games, including chess, Go, tems. It explains how and where interface home -entertainment bridge, and backgammon are to find the best components and systems, including off-air anten- also covered, as are play -by- peripherals at the lowest possi- nas, stereos, and VCR's, with mail classics like rotisserie static -control products, circuit- ble prices, and explains which home satellite TV receivers. baseball and Diplomacy. The board accessories, lighting and software packages will best suit Miniature Satellite Dishes: book also covers MUD'S, optical aids, workbenches, sol- a variety of needs (including The New Digital TV is available MOO's, and MUSH'es -par- dering supplies, cables, multimedia applications). The for $20 plus $4 shipping and ticipatory narrative adven- connectors, LAN installation money- saving guide also con- handling from Baylin Publica- tures-in which players build and maintenance products, tains a review of operating tions, 1905 Mariposa, Boulder; and explore virtual worlds from shipping containers, and more. systems and a handy list of CO 80302; Tel. 303-449 -4551; the USS Enterprise to worlds Jensen brand tools have a life- troubleshooting techniques, Fax: 303-939-8720. based on Anne Rice's vampire time guarantee, and shipping is making it a valuable reference CIRCLE 89 ON FREE 86 chronicles. free in the continental U.S. for those who are planning to INFORMATION CARD

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Introduc- BP276- Shortwave 1E1 BP88 -How to Use BP113 -30 Solder- An totr°dction BP177- i m°.,t Corn- Superhet Receiver OpAmps - -- $5.95- A de- less Breadboard Pro- c r tion to Computer op a.. c signers guide that coy- jects-Book 2...$5.95. °n1cnt'Qn+ munications...$5.95. Construction...$6.95. ers operational ampli- Numerous hobbyist pro- Details on types of Provides construction details, including coil wind- fiefs. Serving as both a _. jects of useful gadgets modems and their suit- source book of circuits ;'r' and circuits using "Ver- ability for specific appli- ing, of a number of ad- design receivers and a reference book for -' zyr-; - obloc" breadboards. All cation, plus details of vaned- which should have per- design calculations. The _ 1 the breadboard projects connecting various com- - formance levels at least text is non -mathematical - in this book are based puters to modems, and equal to commercial sets - and easy to understand on CMOS logic integral- modems to the tale- of complexity. by most readers. ed circuits. phone system. similar

to PCP103- Practical MIDI Hand - 13°é,-r'. Guido BP61- Beginners Guide to Digital -': ,. BP285 -A Beginners Guide Modern Electronics Components. -. book...$9.95. The Musical Instrument T ° p Techniques...$5.00. Covers the basics a TM' '^ is surrounded by of digital techniques--decimal, binary, $6.50. It is easy for newcomers to elec. Digital Interface (MIDI) This octal and hexadecimal numbering sys- tonics to become confused. There are a a great deal of misunderstanding. musicians and techni- tems are covered plus insights on "` great many different types of compo- book is aimed at weighted and non -weighted binary- nents available often with numerous clans who want to explore the vast ca- It -based codeddecimal codes and alpha -numeric variations of each type. This book pre- 3' pabilities of MIDI. covers MIDI codes. The basic building blocks of cir- ° sents the reader with a vast amount of equipment you can use: keyboards, cuit logic, the common AND, OR, NAND, invaluable parts information to enable FQ drum machines, sequencers, effects 001- NOR and EXCLUSIVE -OR gates and the right component to be selected every urns, mixers, drum pads guitars. There's computer music. bi- stables, are thoroughly covered. time for repairs and projects. also a section on

- PCP109- Everyday BP90 -Audio Pro- H tO ' 8P121 -How to De- BP44 -IC 555 Pro- Audio Proiect. c sssan Ct.. Data Book the u°eg IAAAA sign and Make Your Jects...$5.95. Every so Electronics Jects...$5.50. Details vor t>''n P". construction of pream- Own PCBs...$5.75. Sim- often a device appears -.. $10.00. An invaluable .__.. -_. plifiers and mixers, pie methods for copying that is so useful that one source of electronics in- ` power amplifiers, tone printed- circuit board de- wonders how life went formation -the text con- controls and matching signs from magazines on before without it. The tains sections that deal projects. All projects are and books on to copper. 555 timer integrated -cir- with the underlying the- `\ fairly simple to build and Covers all aspects of cuit chip is one such de- ory of electronic circuits a wide range of include a number of simple PCB construction vice- Included are basic and - and general circuits used practical electronic uses - '- board layouts and wiring as comprehensively as diagrams. possible. by most hobbyists. for everyone.

Electronic Power Supply BP6O-Practical Construction [ BP297- Loudspeakers for Musl- ELECTRONIC E PCP110- Handbook. -- $10.95- All types of power of Pre -Amps, Tone Controls, Filters toua.a kart clans -- .$6.25. Contains all the informa- POWER SUPPO' %°"t*wi for tion that a working musician needs to ro;u'm,, supplies used for electronics purposes and Attenuators...$5.50- The book of- wx.a( n. tars practical designs and details there- know about loudspeakers; the different are covered in detail, starting with cells and batteries and extending by way of by enabling the project- builder enthusi- 1 types, how they work, the most suitable ,B,may linear to ast to construct, with the minimum of ' for different instruments, for cabaret rectified supplies and stabilizers li modem switch -mode systems , IC switch - , 3 1 work, and for vocals. n gives tips on con- I . difficulty and expense, various audio pre- " amplifier and tone control circuits, etc., structing cabinets, wiring up, available mode regulators, DC- converters and inverters. The devices, their operating prin- which may be used with home -con - °' . fittings, finishing and how to connect structed audio equipment or even corn- mufti- speaker arrays, etc. Includes ten ciples and typical circuits, are dealt with plex commercial gear. enclosure designs with plans. in detail,

_ PCP101- Practical BP315- Introduc- w,.a #228 -Essential e P254-From íq°x.Wet,wá.. from Atom. Atoms to Amperes... Digital Electronics lion to the Electro- ,.,,,w Theory for the Hobby- to Amp.r. Ist...$5.25. Supplies to $6.50. Explains in crys- Dy91tali Ks Handbook...$9.95. An _ magnetic Wave...$5.95. tal -clear terms the fun- $1iz_ZGY.. introduction to digital Or- .° A fundamental and the hobbyist background damentals behind the N cuits, logic gates, bi -sta- easy -to- understand ap- knowledge tailored to the of whole of electricity and f bles, timers, micro- ; proach to a complicated 1 specific requirements. v.,: theory topic. The begin- j t \'Uli their activities. Relevant electronics. Really helps' processors, memory "? A ner requires no more material is presented in you to understand the - and I/O devices. spe- \ *.: - dal feature of the book \ than elementary mathe- a readable manner with basis of the complex x of mathe- I,I subject perhaps for the is the section on digital .. . -, matics and basic knowl- a minimum maties. first time ever. - test gear projects. edge of electronics.

TEST EQUIPMENT SPECIALS SUBSTITUTION GUIDES FOR HOBBYISTS BP239- Getting the Most from Your Multimeter...$5.95 BP85- International Transistor Equivalents Guide...$7.50 Covers analog and digital gear, component and gear testing. The ultimate guide to replacing foreign and domestic transistors. BP267 -How to Use Oscilloscopes & Other Test Equipment...$6.95 BP108-- International Diode Equivalents Guide...$5.95 hobby types. Get with the next step to proficient troubleshooting. Rectifiers, Zeners, LEDs, OCIs, diacs, triacs...all PCP111- Electronic Test Equipment Handbook.. -$13.95 BP140- Digital Equivalents and Pin Connectors...$12.50 The all- inclusive text covering test gear you'll use! A master reference for builders who design projects.

ELECTRONIC TECHNOLOGY TODAY INC. SHIPPING CHARGES IN SORRY No orders accepted Number of books ordered USA AND CANADA & Canada P.O. BOX 240, Massapequa, NY 11762 -0240 outside of USA $0.01 to $5.00 $1.50 Total price of merchandise $ $5.01 to $10.0020.00 $2.50 Shipping (see chart) S Name $10.01 to 2 0.00 $3.50 Subtotal $ $20.01 to 30.00 $4.50 Address Sales Tax (NYS only) S $30.01 to 40.00 $5.50 Total Enclosed City State Zip $40.01 to 50.00 $6.50 5 above funds! PEt $50.01 and $8.00 All payments must he in U.S. 87

www.americanradiohistory.comAmericanRadioHistory.Com NEW PRODUCTS

The MFJ -452 "Perpetual Memo- keys for easy use. The MFJ -452 ry" CW keyboard from MFJ also features an iambic keyer Enterprises features eight 250 - for fast break -in-by plugging in character nonvolatile message an iambic paddle you can use it memories, a 150 -character as a full- featured keyer. type -ahead buffer, a two -line The Morse code trainer al- LCD readout, an RFI -sup- lows the user to practice or pressed keyboard, and a teach in Farnsworth or normal "Perpetual powerful Morse code trainer. code. Letters, numbers, punc- Even the hunt -and -peck typist tuation marks, and prosigns can Memory" CW can send perfect CW mes- be selected in any combination sages, because the buffer for practice. Keyboard smoothes out one's typing and The MFJ -452 Morse AT101- gives him or her more time to compatible keyboard, which compose. There is no computer plugs into a compact interface, to boot up, and no program to costs $129.95. For more information, contact MFJ Enterprises, Inc., P. O. Box 494, Mississippi State, MS 39762; Tel. 601 -323 -5869 or being distracted. Reaction tun- 800 -647 -1800 for orders; Fax: ing a receiver in drive -by 601 -323 -6551. operation provides instant, CIRCLE 102 ON FREE hands -free monitoring of the de- INFORMATION CARD tected t transmissions. To distinguish actual radio fre- RADIO -TRANSMITTER quencies from background DETECTOR noise, Optoelectronics' patent - ¡'.I Aimed at the security, sur- pending Digital Filter/Capture veillance, law- enforcement, and technology is used. The beeper hobby monitoring markets, the and LCD backlight are switch - Scout from Optoelectronics is a selectable on power up. A NiCd handheld device for detecting battery pack provides at least radio transmitters in the near six hours of portable operation. field. An AC adaptor/charger is in- For walk -by applications, the cluded; a 12 -volt DC adaptor is Scout can automatically detect optional. and record 200 unique frequen- The Scout radio-frequency cies and up to 250 repeat hits detector, complete with AC load. The device allows the user on any that were previously re- adaptor /charger, 3.5 -inch disk to save his or her messages corded. When used with the with PC- compatible utilities, and and settings for up to 20 years miniature DB32 antenna, the user's manual, costs $399. The without power or batteries. Scout will fit in a pocket, operat- DB32 miniature VHF /UHF an- The display simultaneously ing in a completely automatic tenna costs $29, and the CX12- shows what is being typed on mode, and will signal the user to-RS-232C interface costs $89. one line and what is being sent with a pager-style vibration For more information, contact out on the other. The user can when a frequency is recorded. Optoelectronics Inc., 5821 NE review stored messages and After recording, the Scout data 14th Avenue, Ft. Lauderdale, FL keyboard settings, and can spot can be downloaded into a com- 33334; Tel. 305 -771 -2050; and correct any typing errors. puter using the supplied Fax: 305 -771 -2052. Thanks to RFI suppression, software and an optional TTL to CIRCLE 103 ON FREE the CW keyboard won't lock up RS -232C interface converter. INFORMATION CARD or send unwanted characters. In drive -by mode, the built -in Single -touch function keys beeper signals when the Scout SERVICE KITS make it easy to store and recall records a new frequency with a Two digital multimeter service messages; set speed, weight, double beep. A single beep kits from Fluke each include a and tone; set up serial number- indicates a hit on a previously rugged handheld DMM, along ing; and turn on and off the recorded frequency. Automatic with the accessories and train- transmitter tune. Commonly operation allows the driver to ing materials needed to perform 88 used prosigns are assigned monitor frequencies without electrical measurements.

www.americanradiohistory.comAmericanRadioHistory.Com The Fluke 23 kit provides the well as to house the switch that patible computers -at the industrial, electrical, and HVAC activates the boards' circuitry. office, home, or on the road- technician with a Fluke Model The number of boards that can without having to download your 23 analog /digital -display multi - be stacked is limited only by macros to floppy. The device meter, an 80i -400 clamp -on AC- space, and the boards can be weighs just 16 ounces and fits in current probe, a TL20 test -lead interconnected. The box has a briefcase. set, and a C17Y case. The kit mounting slots on all four sides. The user can quickly type any also includes electrical and The die -cast aluminum en- letter, command, or function HVAC/R application notes and closures come with channeled with one hand by pressing key training materials for DMM walls for easy board mounting. combinations of one to five fin- users. Because the lid forms an effec- gers, similar to playing chords The Fluke 87 kit provides the tive screen against RFI, they on a piano. ChordEasy software user with a Model 87 analog/ are ideal for RF circuits. The allows a library of macros and digital multimeter, an 80i -400 sheet -metal aluminum boxes, shorthand "WordChords' to be clamp -on AC- current probe, a consisting of two pieces that TL20 test -lead set, a C28Y phone- wiretap- detector alarm slide together, allow the builder case, and a video titled "Under- system protects private phone to access the prototype boards standing Harmonics." Additional lines from eavesdropping and from two sides as well as from training materials in the kit in- tampering. The unit continu- the top. clude the "High- Performance ously monitors the phone line The metal cabinets are de- Guide to DMMs" application for suspicious changes in elec- booklet and electrical, harmon- trical characteristics, and alerts ic, and HVAC /R application the owner with an audible tone notes. when they occur. The small, The list prices for the Fluke microprocessor- contro led unit 23 and the Fluke 87 service kits snaps easily into place and can ®_OW OWN be checked remotely. II The SC1100 wiretap- detector system costs $139. For additional information, contact Security Call, 15425 Los Gatos signed to suit a large variety of Blvd., Los Gatos, CA electronics projects. Slots are 95032 -2541; Tel. 408 -356 -6509 located on the sides of the or 800-334-0074; cases for cooling purposes. The Fax: 408-356-0758. heavy -duty instrument case CIRCLE 105 ON FREE splits apart so that the builder created to save time and reduce INFORMATION CARD can access the prototype errors. Frequently used phrases boards from all sides. Four plas- and commands of up to 250 tic feet secure the case in place characters can become macros PROTOTYPE BOARDS on a desk or table. The case that can be entered with just AND COMPATIBLE accommodates various board - two chords. Those features BOXES mounting positions. make the BAT keyboard popular the and visually are $309 and $469, respec- Jameco's line of 15 printed -cir- Prices for the prototyping with physically with pro- tively. Those prices represent a cuit boards and 15 matching boards range from $3.95 to impaired as well as 10% cost savings over purchas- boxes features ABS speedy $14.95. Prices for the boxes grammers, desktop publishers, ing the items separately. For boxes, die -cast aluminum en- range from $2.25 to $9.49. For and CAD and graphic designers further information, contact closures, sheet -metal aluminum more information, contact Jame - who need to keep one hand free for a mouse. Fluke Corporation, P. 0. Box boxes, and heavy -duty instru- co Electronics, 1355 Shoreway using 9090, Everett, WA 98206; ment cases. The compatibility Road, Belmont, CA 94002; Letter and number chords Tel. 800 -44- FLUKE; between boards and boxes give Tel; 415 -592-8097; can be learned in about an "A," for Fax: 206 -356 -5116. electronics enthusiasts a quick Fax: 415 -592 -2503. hour. To enter the letter CIRCLE 104 ON FREE start on their projects. CIRCLE 106 ON FREE example, the user simulta- INFORMATION CARD The pre -cut boards also allow INFORMATION CARD neously keys the thumb and the builder an immediate start first three fingers. Typical typing on prototyping circuits. Each speeds reach 25 to 45 words - TELEPHONE WIRETAP board has two or four mounting MACRO KEYBOARD per- minute with one hand. DETECTOR holes and is compatible with The BAT (Biomechanical -Auto- The BAT keyboard with bat- including custom With inexpensive, easy -to -use Jameco's PC -board mounting mated Technology) Personal tery backup, wiretapping equipment now hardware. The As- inch -thick Keyboard from InfoGrip, Inc. carrying case, costs $199. A 10- minute video demonstration readily available, both busi- boards are made of laminated compresses all the capabilities the of the nesses and individuals are glass epoxy, are copper-clad, of a traditional keyboard into a costs $2.95; price will ap- increasingly concerned about and have a solder mask on one seven -key unit that can be used demonstration video be of a maintaining their privacy. As the side. with one hand. Its battery back- plied toward the purchase keyboard. For more information, threat of surveillance becomes The boxes are designed for up stores macros so they don't obvious, businesses recognize convenience and durability. The have to be reactivated every contact InfoGrip, Inc. at -0921. the need to protect their infor- ABS speedy box, for instance, time the keyboard is turned off. 800- 397 mation. can be used to enclose and The BAT keyboard can be used CIRCLE 107 ON FREE Security Call's SC1100 tele- protect the boards inside, as with several different PC -com- INFORMATION CARD 89

www.americanradiohistory.comAmericanRadioHistory.Com LIGHT-UP REMOTE tuner; two positions that bypass accuracy. Continuity CONTROL checks are the antenna tuner but keep the aided by a built -in buzzer. The Late -night TV viewers won't SWR /Power meter active; and tester measures 7.5 x 4 x 1.75 have to fumble in the dark for two positions for the built -in inches and weighs approxi- the right remote -control buttons dummy load (tuned or direct). mately 1.3 pounds. It is powered with Radio Shack's Light -Up re- Using the tuned dummy -load by six 'AA" batteries. mote. The keypad lights up on position allows the user to pre- The Model DI -2000M insula- command. The most frequently set the tuner for the band in use tion -test meter, complete with used controls (volume and without causing on -air inter- test leads, batteries, strap, and channel up /down) are brighter current. The device separates ference. The tuning system carrying case, costs $120. For than the others, making it easier the hot/live conductor from the itself uses two large, con- additional information, contact to quickly find the correct neutral (and ground) wire. Two - servatively rated, continuous - HC Protek, 154 Veterans Drive, button. or three -prong plugs can be rotation capacitors and a 12- Northvale, NJ 07647; tested by placing the line sepa- position switched inductor. A Tel. 201 -767 -7242; rator between a standard wall heavy-duty 1:4 balun is built -in, Fax: 201 -767 -7343. outlet and a power cord. A x 10 along with binding posts for CIRCLE 111 ON FREE multiplier range allows precise long -wire antennas and SO -239 INFORMATION CARD measurements of low current connectors for coaxial -fed an- levels. tennas. The Model 480172 line sepa- The T-1000 antenna tuner RS -232 FREQUENCY rator costs $15. For additional has a list price of $149.95. For COUNTER information, contact Extech In- further information, contact Powered from the RS -232 port struments Corporation, 335 Tucker Electronics and Comput- handshake lines, the Model Bear Hill Road, Waltham, MA ers, 1717 Reserve St., Garland, 232FC frequency counter from 02154 -1020; Tel. 617-890 -7740; TX 75042 -7621; B &8 Electronics allows you to Fax: 617-890-7864. Tel. 1- 800 -527 -4642. make frequency measurements CIRCLE 109 ON FREE CIRCLE 110 ON FREE of TTL-level signals through INFORMATION CARD INFORMATION CARD your RS -232 port. If the handshake lines are not available, a HF ANTENNA TUNER INSULATION -TEST 12VDC external supply can be The Tucker T-1000 antenna METER used to power the converter. tuner operates from 1.8-30 MHz The Model D1 -2000M insulation - The 232FC makes frequency and matches any transceiver or test meter from HC Protek mea- measurements from 5 Hz to 2 receiver to almost any antenna sures insulation resistance as MHz and duty -cycle measure- with up to 300 watts of power - well as AC voltage and con- The Light -Up remote can be handling capability. It features a tinuity. The rugged, easy -to -use used to control a TV, VCR, large, lighted cross -needle meter has a built -in megohm cable box, and one other de- meter that simultaneously mea- meter with a range of 2 -2000 vice. It is programmed to sures forward or reflected power megohms (± 2 %) at a terminal operate your specific equipment and SWR. The metering system voltage of 500 volts. The meter by entering the three -digit codes measures both peak and aver- measures AC voltage from 0 to for your models. The owner's age power. A built -in 300 -watt 750 volts with ±1% accuracy. manual includes a list of codes dummy load uses a special Resistance measurements for hundreds of models. The ceramic construction that actu- range from 0 to 200 ohms at remote also works with Radio 0.1 -ohm resolution and ±1°h Shack's Plug 'n Power modules to control lights and appliances around the home. The Light -Up remote sells for ments from 5 Hz to 50 kHz. approximately $29.99 at Radio Simple commands allow you to Shack stores nationwide. For make measurements with your additional information, contact own program. The device is Radio Shack, 700 One Tandy shipped with software that logs Center, Fort Worth, TX 76102; and plots frequency and duty - Tel. 817 -390 -3300. cycle information, and also displays histograms. CIRCLE 108 ON FREE Sample code INFORMATION CARD in BASIC, Pascal, and C that demonstrates the 232FC com- ally becomes more resonant as mands is provided. it heats up. LINE The 232FC frequency counter SEPARATOR The T -1000 has an eight -posi- costs $69.95. For further infor- You can safely monitor AC line tion front-panel switch that mation, contact B &B Electronics current with the Model 480172 allows the user to alternate be- Manufacturing Company, 707 line separator from Extech In- tween two coax -fed antennas Dayton Road, P.O. Box 1040, struments. It allows easy (either directly or through the Ottawa, II 61350; Tel. 815 - access to a two- or three -wire tuner); a balanced line or wire 434-0846; Fax: 815- 434 -7094; power cord, so that a standard antenna; a bypass position that BBS: 815-434-2927. clamp meter then can be used allows switching directly to the CIRCLE 112 ON FREE 90 to easily and safely record line antenna, thereby bypassing the INFORMATION CARD

www.americanradiohistory.comAmericanRadioHistory.Com 114. 11DTV Kcwlolion Gei owe You rtt wed!

Popular Electronics

Plans for the world's zaniest plaything- Popular Electronics back issues are available although quantities of some September 1989 issues are nearly exhausted. Here's an opportunity to complete your collection, or obtain a selected back issue you cannot find elsewhere. This offer is valid fornalaphi""tlaire ctrimics only when using the coupon on this page or a photo copy, ...,..,ne tharw,, r-- SpecialAre Back Issue Offer! 1

Please circle the issue(s) ordered:

ww o. Jan. Feb. Mar. Apr. May June July Aug. Sep. Oct. Nov. Dec. nVaecrnrit, lot 2 3 11 12 1987 1 it I - not available 1g87_1988 back Issues 24 1988 1 Put together your own 35 36 Macintosh computer- 1989 25 26 27 28 29 30 31 32 33 34 September 1991 1990 37 38 39 40 41 42 43 44 45 46 47 48

1991 49 - 50 51 52 53 54 55 56 57 58

1992 59 60 61 62 63 64 65 66 67 68 69 70

1993 71 72 73

Note: Issues prior to November 1988 are "Hands -on Electronics" -the predecessor of Popular Electronics. How to determine cost!

Price per copy Quantity United States Canada -Foreign 1 -5 $6.50 US $6.50 US ' 6 -11 5.50 5.75 $8.00 US Build the Tesla Coil 12 -23 5.00 5.25 7.50 that went sq;uare!- 24 and more 4.50 4.75 7.00 August 1989 Prices include handling and shipping. Prices subject to change. All orders payable in U.S.A. funds only, via international money order, check drawn on a U.S.A. bank, or acceptable credit card (Visa, MasterCard) in U.S.A. funds. Allow 6 -8 weeks delivery. Foreign orders may take longer. 'Minimum foreign order-6 issues.

Visa MasterCard USA Bank Check p US or Int. Money Order [Note: Credit Card minimum order is $15.001

Credit Card Number Exp. Date / Signature Name Address

City State ZIP

Send Orders To: CLAGGK, Inc., P.O. Box 4099, Farmingdale, NY 11735. Sorry, no telephone orders. Take a chance on L J our - Dice- Roulette p-oject- April 1989

www.americanradiohistory.comAmericanRadioHistory.Com THE IMAGINATION NETWORK creasingly difficult to get together with (Continued from page 50) her friends for a game. He thought how wonderful it would be if she, and TIPS FOR MAIL ORDER others like her, could always find PURCHASE equipment, and how to fight battles. I friends for a game of cards, without also answer questions about other as- needing to leave the comfort of her It is impossible for to pects of the network, monitor a own home. Based on that concept, us verify the claims of ad- vertisers, including but not limited to product portion of the bulletin boards to en- INN, (originally called The Sierra Net- availability, credibility, reliability and existence sure that community standards are work) was created. of warranties. The following information is pro- maintained, and deal with an occa- In 1993, AT &T and General Atlantic vided as a service for your protection. It is not sional troublemaker. We have mem- Partners both invested in The Sierra intended to constitute legal advice and readers are advised to obtain independent advice on bers from 8 to 80, and INN is first and Network and the name was then how to best protect their own interests based foremost a family place. changed to The ImagiNation Net- upon their individual circumstances and juris- dictions.

1. Confirm price and merchandise information with the seller, including brand, model, color or finish, accessories and rebates included in the price.

2. Understand the seller's return and/or refund policy, including the allowable return period, who pays the postage for returned merchandise and 4.R whether there is any "restocking" or "return" charge.

3. Understand the product's warranty. Is there a manufacturer's warranty, and if so, is it for a U.S. or foreign manufacturer? Note that many manufacturers Foots of Okla and shadow titter the assert that, even if the product floor. comes with a U.S. manufacturer's warranty, if you The crumbling stones and cracked purchase from an unauthorized dealer, you are not covered by the manufacturer's warranty. granite act as testimone to the war e Your If brewing between the Prarsis and Erebus tic tion in doubt, contact the manufacturer directly. In armies that dominate this domain. addition to, or instead of the manufacturer's war- You encounter y Kaatroths. ranty, the seller may offer its own warranty. In either case, what is covered by warranty, how long is the warranty period, where will the prod- If you are a fan of adventure/role -playing games, you'll love what you will find in uct be serviced, is there a charge for service, what MedievaLand, one of the lands in INN. do you have to do to obtain service and will the product be repaired or replaced? You may want INN takes great pains to ensure that work. The interest of those larger com- to receive a copy of the written warranty before an enjoyable time can be had by all. panies was generated by their intent placing your order. If you should, by chance, receive a to use INN as a showcase and testing 4. Keep a copy of all transactions, including message from another member that ground for a variety of on -line com- but not limited to cancelled check, receipt and correspondence. you find offensive, you have the op- puter games, from Sierra and other For phone orders, make a note of the order including merchandise ordered, tion to click a "complain button." That companies. Many price, exciting things are order date, expected delivery date and salesper- button records the exact message planned for the future, but we'll keep son's name. along with the offender's name and those as surprises for now! account 5. If the merchandise is not shipped within the number for INN personnel to I may be biased, but I think that The promised time, or if no time was promised, with- review, and the staff will take action on ImagiNation Network is closer to "vir- in 30 days of receipt of the order, you generally it, if warranted. Occasionally, some- tual reality" than any other computer have the right to cancel the order and get a refund. thing improper gets posted after our network that I've explored. It's simple daily monitoring, or a member be- enough for the youngest child to en- 6. Merchandise substitution without your ex- comes exceptionally unruly, in which joy, yet diverse enough to challenge press prior consent is generally not allowed. case the offending post (or even the even the most competitive adult. INN 7. If you have a problem with your order or the member) will be removed when has grown rapidly from just a few hun- merchandise, write a letter to the seller with all the pertinent information and keep a copy. called to our attention. dred members in 1991, and is quickly approaching the 200,000- member 8. If you are unable to obtain satisfaction from Some Background. The ImagiNa- mark as this article is being written. the seller, contact the consumer protection agency in the seller's state and your local Post tion Network's cyberspace communi- If all that sounds like fun, you can Office. ty is continually being expanded and call 1- 800 -Imagin -1 to obtain the soft- upgraded. It was conceived by Ken ware, which costs $5.95 and includes If, after following the guidelines, you experience a problem with a mail order advertiser and Roberta Williams, the founders of a free trial. The basic membership that you are unable to resolve, please let us Sierra On -Line Inc. Folklore has it that package is $9.95 monthly with 5 hours know. Write to Advertising Department, Ken's grandmother was a person who of on -line time included. Give the Gernsback Publications Inc., 500B Bi- County loved to Blvd. Farmingdale, NY 11735. play cards, but because of ImagiNation Network a try; I think you 92 her advanced years found it in- will enjoy it immensely. Be sure to include copies of all correspondence.

www.americanradiohistory.comAmericanRadioHistory.Com FREQ.- RESPONSE TESTER (Continued from page 56) Popular Electronics BOOKSTORE

(1995 back issues) $5.00 211 Radio- Electronics (1991 back issues) . $5.00 AUDIO LEVEL control using your scope as 225 Popular Electronics Write in issues desired Write in issues desired a waveform monitor with internal 224 Popular Electronics (1994 back issues) $5.00 210 Radio-Electronics (1990 back issues) . $5.00 oc- sweep, to make sure no clipping Write in issues desired Write in issues desired curs. Switch S2 into SWEEP mode, and (1993 back issues) $5.00 223 Popular Electronics REPRINTS REPRINTS set your scope to external sweep as Write in issues desired you did during calibration. If you 222 Popular Electronics (1992 back issues) $5.00 174 Electronics Comics (The Best of) $2.00 Write in issues desired own log scale using Fig. 5, 173 From Not-Working to Networking made your issues, 221 Popular Electronics (1991 back Troubleshooting Local -Area Networks $5.00 set your horizontal gain to match its Jan., Mar. not available) $5.00 172 33 Bench -Tested Circuits $2.00 width. By adjusting the vertical gain, Write in issues desired 171 36 Time Tested Circuits $2.00 you should be able to see the DUT's 220 Popular Electronics (1990 back issues) $5.00 Write in issues desired response over the entire frequency 170 High -Voltage Projects for Fun and EH94S Experimenters Handbook Science Book 1 $4.00 spectrum. Summer Edition (1994) $5.00 170A High-Voltage Projects for Fun and Here are a few hints: Although the EH94W Experimenters Handbook Science Book 2 $4.00 Winter Edition (1994) $5.00 response display seems most easily 169 Think Tank (133 Circuits) $3.50 EH94 Experimenters Handbook (1994) $5.00 viewed with SWEEP RATE control R29 set to 169A Think Tank Vol. 2 $3.00 EH93 Experimenters Handbook (1993) $5.00 maximum, the low- frequency portion 168 Fact Cards ( #34 -66) $3.00 EH92 Experimenters Handbook (1992) $5.00 of the display (the left side) will not be 168C Fact Cards ( #67 -99) $3.00 EH90 Experimenters Handbook (1990) $5.00 The very accurate with that setting. HH94S Hobbyist Handbook 168D Fact Cards ( #100 -132) $3.00 Tester's lowest output frequency is Spring Edition (1994) $5.00 167 Designing With IC's $4.00 about 20 Hz. Because that frequency HH94F Hobbyist Handbook 166 Collected Works of Mohammed Ullyses Fall Edition (1994) $5.00 Fips(62 pages, April Fools Collection) $5.00 is constantly being modulated, if the HH93 Hobbyist Handbook (1993) $5.00 frequency increases significantly be 165 How to Repair CD Disc Players $5.00 HH92 Hobbyist Handbook (1992) $5.00 164 Modern Electrics (April 1908) $3.00 fore a single 20 Hz -cycle is com- HH91 Hobbyist Handbook (1991) $5.00 TV 20 Hz is 163 Receiving Satellite $5.00 pleted, then your test at HH90 Hobbyist Handbook (1990) $5.00 162 Build Your Own Satellite TV Receiver $5.00 invalid. For that reason, the slowest GIZ Gizmo -The Consumers Guide to sweep rate should be selected when Electronics $5.00 161 Descrambling (Feb. 1984) $4.00 seriously examining low -end re- Radlocraft 1993 Projects for Hobbyists $5.00 160 New Ideas - 42 Circuits $3.50 215 Electronics Now (1995 back issues) $5.00 159 Low Frequency Receiving Techniques sponse. A storage scope is of course Write in issues desired Building and using VLF Antennas $5.00 ideal for that. 214 Electronics Now (1994 back issues). $5.00 158 Electro Importing Co. Catalog Note that the vertical display of your Write in issues desired (Circa 1918) $5.95 (1993 back scope simply reads peak -to -peak 213 Radio -Electronics /Electronics Now 157 All About Kits $2.00 issues) $5.00 voltage, which is very different from PC Write in issues desired 156 How To Make Boards $2.00 the scale normally used for decibel 212 Radio- Electronics (1992 back issues) $5.00 154 How To Repair VCR's $3.50 audio. To put things in perspective, a 4 -6 weeks for delivery. 50 percent dip in vertical deflection To order any of the items indicated above, check off the Please allow ones you want. Complete the order form below, include to a -3 -dB drop when To place a credit card order by phone, Visa or Master- corresponds your payment, check or money order (DO NOT SEND card only, monitoring power amplifiers, and a CASH), payable to and mail to Claggk Inc., Reprint CALL: 516- 293 -3751. -6 -dB drop when testing almost any Department, P.O. Box 4099, Farmingdale, NY 11735. other audio device. To use your Visa or Mastercard, complete the following: Finally, you might wish to occasionally touch up the low- frequency cal- my Visa - Mastercard ibration via the access hole you BIll drilled for R24. As before, leave the Card No Tester powered -up for a few minutes Exp Date before proceeding, and then per- Signature as form the calibration procedure MAIL TO: Claggk Inc. previously described. Reprint Bookstore, P.O. Box 4099, Farmingdale NY 11735 All payments must be in U.S. funds SHIPPING CHARGES IN USA & CANADA We only ship to USA & $0.01 to $5.00 $1.50 $30.01 to 40.00 .... $5.50 SORRY - $5.01 to $10.00 $2.50 $40.01 to 50.00 .... $6.50 Canada

$10.01 to 20.00 $3.50 $50.01 and above . $8.00 $20.01 to 30.00 $4.50 Total price of merchandise 5 Shipping Charge (see chart) 5 Subtotal 5 Sales Tax (New York State Residents only) S

Name Total Enclosed 5

Address "That explains the microchips." City State Zip PE 395 93

www.americanradiohistory.comAmericanRadioHistory.Com imagine from the above discussion, RAIN FOREST RESCUE: ELENCO TRAINER there's quite a bit to this unit. As a result, (Continued from page 24) TO HELP SAVE HALF OF building the kit requires quite a bit of work -too much to be completed in THE PLANTS AND puts to "see" multiple switch transitions just one evening -even a long eve- ANIMALS ON EARTH instead of a single one. The logic - ning, at a frantic pace. Fortunately, switch outputs are conditioned so that the kit is built in sections that can be In the rain forest, the sounds of fires only one transition is generated at the done at a leisurely pace, one section and bulldozers are replacing the sounds of nature. output for each throw of the switch. per evening, for example. That also Also included are 8 LED readouts makes it ideal for educational situa- Recent studies show that the destruction of the rain forests wipes out 17,000 plant that can indicate the status, high or tions, as the kit is for perfect elec- and animal species each year. That's low, of up to eight points in a circuit - tronics students to build one section about 48 extinctions per day, two per an 8 -bit data bus is one example. The per class, per week, per course, or hour. These are plants and animals that digital section also includes a built-in whatever. will simply cease to exist, gone forever from the planet. And the toll mounts clock. The clock output is a 5 -volt The assembly instructions, which every day. peak -to -peak square wave that can are clear and easy to follow, are laid Join The National Arbor Day Founda- be set from 1 hertz to 100 kilohertz. out in an order that's designed to tion and support Rain Forest Rescue to All of that is housed in a case that catch errors on the way and lead to a help put a stop to the destruction. When measures about 12 by 16 inches. The properly working unit when finished. you join, the Foundation will preserve case includes a molded well that can Two separate PC boards must be as- threatened rain forest in your name. be used to store loose parts, and a sembled. Neither of the boards are a An area of rain forest the size of 10 city cord holder is built into the lid. large project in themselves, and ei- blocks is burned every minute. Help stop the destruction. Before the sounds As you can see, the XK -525 is an ther could be built in one evening. of nature are replaced by the sounds of invaluable aid in designing circuits. However, one of the boards is built in silence. However, as it is a kit, it must be built Iwo stages, and fully tested after each To contribute to before it can be used. Let's see what's stage. Rain Forest Rescue, call involved in doing that. After that part of the construction is 1 -800- 222 -5312 finished, the bulk of the work in assem- ®The National Building the XK -525. As you might bling the XK-525 is in wiring the dif- Arbor Day Foundation ferent components together. Every- thing mounts on the back side of a metal front panel, and wires connect LDtedronir. W Rs". er4y things together. It's a lot of work, but `. oz \ .'.. well worth it in the end. -- , While putting together the XK -525 is . i, 1...Y. ,,...,. 14.1 a big job, it's the kind of activity that many of our readers enjoy. When complete, the result is a very useful instrument for the hobbyist who put it together. Building the XK-525 involves a little bit of everything, from PC- Your Ticket To board assembly, to wiring, to mechanical assembly. It's actually a very good kit for someone who's starting to SIJCCES, get more serious about his or her electronics hobby; it helps the user brush Over 28,000 technicians have gained admit- tance worldwide as certified professionals. up on building skills and yields a ver- Let your ticket start opening doors for you. satile platform for future digital- and ISCET offers Journeyman certification in analog- circuit design. For more infor- Consumer Electronics, Industrial, Medical, mation on the XK-525 Digital /Analog Communications, Radar, Computer and (i) Video. For more information, contact the Trainer, contact Elenco Electronics di- International Society of Certified Electro- rectly at the address given in the box e nice Technicians, 2708 West Berry Street. below, or circle no. 119 on the Free t Fort Worth, TX 76109; (817) 921 -9101. w Name Information Card. Address City o FOR MORE INFORMATION State Zip cr) Send material about ISCET and Elenco Electronics, Inc. becoming certified. 150 W. Carpenter Avenue Send one "Study Guide for the Wheeling, IL 60090 Associate Level CET Test." En- Tel 708 -541 -3800 94 L closed is $10 (inc. postage). J

www.americanradiohistory.comAmericanRadioHistory.Com From the Lab

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Probably not! However, through constant playing and using of degrading dry an or wet cleaners, the output of your video tapes has sllowly diminished to unacceptable level and the VCR plays as if it has a head cold! The culprit is most likely clogged and dirty video and /or audio heads. The 3M Black WatchTM Head Cleaner Videocassette uses a patented mag- He stood about five - netic tape -based cleaning formation to remove head clogging debris. No foreign substances such as cloth, plastics or messy liquids and no harsh abra- foot, nine -inches tall, but he more! sive materials are present. The cleaner's usable life is 400 cleanings or was a giant. Billy Thomas. It's easy to use. Place the 3M Black WatchTM Head Cleaner Videocassette in the VCR and press the Play button. A prerecorded message appears clear- Boys &- Girls He ran the ly on your screen and an audible tone is heard, telling you that the cleaning No guess work, you never over clean! Club where I grew up. process is now completed. 3M Black WatchTM Head Cleaner Videocassette SHE IVNS $19.95 Now, I know today it's different. Young people Once your VCR's head cold is cured, and the unit plays like new, consider can buy 3M Black WatchTM T120 Hi face problems I never using the finest videocassette you -the Pro VHS 4410 Videocassette. The 4410 is the highest performing video- even had to think about. cassette available today for use with all standard format VHS recording hard- But that's why now, ware! Here's what you hear and see....A sharp, clear picture- brightest colors - more than ever, we need freedom from streaks, flashes and snow-outstanding high -fidelity audio reproduction- optimum camcorder performance- mairtains recording integri- the Boys & Girls Club. It's surface ty. 3M Black WatchTM video tape is 100% laser inspected to guarantee a positive place where smoothness and drop -out free performance. Videocassette MS. $8.00 thousands of people like 3M Black WatchTM T120 Hi Pro VHS 4410 Billy Thomas help young r people succeed. Does it CLAGGK INC. - 3M VHS Special Offer P.O. Box 4099, Farmingdale, New York 11735 work? It did for me. Pt my for 3M Black WatchTM products! Yes, I like your offer and here is order $ 3M Black WatchTM Head Cleaner Videocassette ($19.95 each) $ 3M Black WatchTM T120 Hi Pro VHS 4410 Videocassette ($8.00 each) 4.00 1- 800 -854 -CLUB Shipping and handling per order $ Total Amount in U.S. Funds only $ No for- New York State residents add local sales tax. Canadians add $6.00 per order. eign orders. Do not send cash.

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www.americanradiohistory.comAmericanRadioHistory.Com SIMULTANEOUS EQUATIONS tered by columns, top to bottom, and NOVEL NIGHTLIGHT then left to right. If you (Continued from page 48) accidentally (Continued from page 38) enter those numbers by rows you are guaranteed to get incorrect results! putting numerical values for variables The entering of the "constants of X 7 inches each, for the sides of the X(1), X(2), and X(3). Those the rows" numbers are (i.e. the numbers to the right nightlight. The top is a 71/4 -inch square the solutions to the original equations. of the equal signs in the standard of glass. You will also need to cut four They represent the unknowns that equation format) takes place in lines pieces of top molding and four were located in the first, second, and 330 -390. After the user enters those pieces of corner molding, using the third columns (respectively) of the numbers, the program then inquires if dimensions given in Fig. 3. standard equation format. Because all the numbers, both coefficients and To assemble the nightlight cover, we were solving for the three node constants, were entered correctly. If apply epoxy glue to the inside edges voltages of the circuit in Fig. 1, the you respond to that question with an of each piece of molding that you are computer's output shows us that: "N" or an "n," the program will then ready to attach. Carefully fit together prompt you to correct your mistakes. the pieces of glass and the mirrors Unknown of column 1 = X(1) = V, = Otherwise, it will continue 18 to the next that make up the sides of the box (the section of the program. mirrors Unknown of column 2 = X(2) = V2 = should be adjacent), and hold The heart 42 of SIM -EQ lies in lines them firmly in place to allow the glue 530 -790. In that section, a process Unknown of column 3 = X(3) = V3 = ample time to dry. When the sides are known as Gaussian is 24 Elimination used assembled, glue the top square of to solve the simultaneous equations. glass to the pieces of top molding. Your version of SIM -EQ should out- Depending on the speed of your ma- After that has fully dried, glue the as- put numbers very close to those listed chine and the number of unknowns in sembly to the top of the glass box. above, but they might not be exactly the equations, that section can take The glass cover should be secured the same. The reason for that is that up to several minutes to complete. to the baseboard, especially if the every type of computer tends to You might need to be patient. Novel Nightlightwill be used by young round -off numbers in a slightly dif- Once all the Gaussian Elimination children. That can be accomplished ferent way during its calculations. calculations are completed, the pro- in a number of ways. On the pro- After several successive calculations, gram proceeds to execute lines totype, a piece of wire is connected the amount of the round -off error in- 800-900, where the final results are between two small screws on op- creases, and hence one computer displayed. On occasion, the program posite corner moldings. Sliding the might output a value of exactly 42, might need to print the error state- wire under the baseboard prevents while another might 41.9996. output ment of line 870, which reads: "ERROR! the cover from being lifted. If you pre- That is completely normal and is not - Equations can't be solved!" That indi- fer, you can attach small latches on an indication that you entered the cates that either there was a mistake opposite sides of the project, instead. program incorrectly. made in inputting the coefficients or With the case assembled, you can constants, or that there are contradic- safely plug in and use the Novel Night - Program Description. The SIM- tions within the equations you are light. So, put an antique VR tube to EQ.BAS program consists of five main dealing with. good use, and brighten up your eve- sections of code that are delimited by The following example of a series of nings while you're at it. asterisk -enclosed comment lines in "contradicting" equations illustrates the program listing. Each of those sec- the type of problem that would result tions will be discussed below. Also, as in an ERROR statement. If you look an additional aid to understanding closely at the following two equations, how the program works, Fig. 2 is a you will see that they do not agree flowchart of its sequence of logic. with one another. One of these equa- The first section of code in SIM -EQ, tions is obviously incorrect: which includes lines 100 through 160, V, + V2 = 6 initializes the program and prints a 2V, + 2V2 = 20 brief introductory screen. It also prompts the user to input the number If you ever see the ERROR message, of unknowns in the series of equations try running the program again on the Avie-! to ÁIVS be solved. As indicated, the en- same data. Then, if you get the ERROR 4:tktib- -F tered number must be within the message again, take some time to range of 1 to 25. determine if your original equations After the number of equations are correct. While it might be annoy- (which is the same as the number of ing to get an ERROR message after unknowns) is entered, the user is asked entering a multitude of numbers into to Input the values of the coefficients the computer, it's better than solving associated with the unknowns. That five or six equations manually, only to occurs in lines 220-320. It Is important discover that your original equations 96 to note that the coefficients are en- were incorrect!

www.americanradiohistory.comAmericanRadioHistory.Com Supplement to Popular Electronics Popular Electronics March 1995

FREE TM construction plans for eeder any of these kits te\ it W Technologies Call 513- 752 -0279 Po- 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 fvequency 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 cal ing 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 on a 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. Change between two separate alone, no computer interface choose mode. Program from any phone directories of callers with a simple needed. on the line using your password. flip of a switch. DTMF Decoder /Logger Vocal Filter Message Module Keep track of ad numbers dialed Telephone Scrambler Electronic 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 it 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 6 -din 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, disolay. 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 scold through and view all numbers operation. over wth new messages. tapes. in memory. \L

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JUMBO SAVINGS MINIATURE TOGGLE 9 VOLT 60 MA LEDS JUMBO D.P.D.T. (ON -ON) SOLAR PANEL ALCOSWITCH # MTM206NPC These 6" X glass enclosed Liton # LTL 327C - 8MM r- 6 Short bat handle,0.25" long. Ideal for eye- catching indicators and photovoltaic panels produce displays. A recent quantity purchase PC terminals $ 25 9 Vdc at 60 ma. Ideal for charging batteries and pow- of these BIG, 8mm diameter, red diffused LEDs III CAT # MTS -82PC each enables us to provide some very special pricing. ering small devices. Put two or more together for more The leads on these devices have been trimmed to 25 for $25.00 100 for $90.00 0.325 ", leaving plenty current and voltage. Includes of room for soldering. hook -up instructions. Normally these parts 5 for $1N. would sell for more ALUMINUM KNOBS than twice our price. CAT # LED -23 CAT # SPL -960 $525 h 6 FLUTE DESIGN W/ INDICATOR 100 1000 for $15.00 for $120.00 LINE Alcoknob # KA7QOB1 /4 0.75" diameter X 0.63 ". kr" LASER POINTER NEW LOW PRICE 6 -32 set screw. CAT # KNB -73 UNIVERSAL IR $1.00 each 25 for $ 18.75 3 FLUTE DESIGN W /SKIRT REMOTE CONTROL AND INDICATOR LINE Alcoknob # KS 500B1/4 The Fox 400 TM wi-eless infrared The "Infiniter "TM # OPON-670 -210 remote control works with most TVs, 0.5" dia. knob with 0.75" dia. Projects a bright red spot up to 100 meters. An excel- VCRs, cable and audio devices. skirt. 0.63" high. 6 -32 set screw. lent business or educational aid. Settings for continu- Works with all major brands and CAT # KNB -75 ous or flashing beam. LED indicator. Low battery indi- lots of not -so -major brands. Use cator. Includes 2 AAA batteries.Hi -tech ergonomic gun- .,; it to replace lost IR remotes or $1.00 each 25 for $ 18.75 metal gray and black case. to combine up to four remotes CAT # LP-210 95 into one unit. User friend- each ly. Includes complete instructions and an 800 7 Vdc MOTOR phone number if problems should occur. Matsushita 480 X 128 DOT Fully guaranteed. # MMX- 7AC O BA Requires 3 AAA 1.25" diameter x 1.25" high LCD ASSEMBLY batteries (not motor. Prepped with 1.61" included). $ 1 each diameter flywheel, pulley Hitachi # LM2158 CAT IR -400 for Federal # and fiberglass mounting Originally built Express, these CAT# DCM -54 brand -new assemblies consist of a board. $100 heavy -duty plastic display hous- 100 for $80.00 ing with a metal mounting "HI -8" VIDEO bracket. Housing size: 13.18" X 4.93" X CASSETTE (USED) 1.2 ". Inside the housing 8 mm Video Camcorder Users!. 2 1'2" 8 ohm SPEAKER and easily removable SONY Hi -8 Special purchase of these 8 ohm, is a stan- Top quality, metal particle 120 Hitachi 1 watt speakers allows us to sell dard minute video cassettes. Used quantities at very special low 480 X 128 for a short time, then bulk - graphic and prices. Mounting frame is 2.6" erased, each cassette has its alphanumeric plastic New, own storage box. square. Overall depth, 0.75." display with buil -in drivers. Requires an external these high quality cassettes sell controller (HD61830 or equiv.). Display area is 9" X for considerably more. CAT# SK -251 10 for $10.00 2.71." Module size is 10.6" Satisfaction Guaranteed, h $3 100 for $75.00 X 4.33 ". Includes spec. 00 CAT # VCU -8 and hook -up sheet. $1 ?5 1000 for $ 600.00 each CAT # LCD -24 2 10 for $28.00 100 for $250.00

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www.americanradiohistory.comAmericanRadioHistory.Com 500 MHz SPECTRIJM ANALYZER $$95

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1 -1300 MHz In One Sweep $1895 MADE IN THE USA ALL NEW SPECTRUM DISPLAY MONITOR PLUS FULL FUNCTION SPECTRUM ANALYZER LET THE SA500A SPOT THOSE HIDDEN SIGNALS .2- 1.3GHz SA1300B THE ULTIMATE Low COST ANALYZER The SA500A easily attaches to any receiver IF output jack. Providing Quality & Performance that's what ITC Spectrum Analyzers are dBm Sensitivity, Center Frequency a panoramic signal display of your 1 -30 MHz and 30 to 2000 MHz known for. 80 dB on &uecn, -110 scanner or communication receiver. The SA500A is a Professional Display, +1- 5KHz Narrow Band Filter (for 5KHz resolution band Spectrum Surveillance Technology Monitor. A Full Function Spectrum width) 50 MHz Marker. DLSPERSIDN ZOOM, Baseline Clipper, Analyzer with +1- 5KHz Narrow Band Filter, Center Freq. Display, 50 Sweep Speed, Adjustable Video Filter, 40dB of Input Attenuation . MHz Marker Generator. Capable of Tuning Duplexes, Amps, Filters Standard on all ADVANTAGE Spectrum Analyzer specials. The Receivers, Transmitters & Perform EMI, RH, FCC, Testing. SA500A SA1300B and SA1800C provide Laboratory Performance at a fraction First affordable Professional Spectrum Monitor /Analyzer for all of the normal cost. The SA1300B $1895.00 -SA1800C .2- 1.3GHz & serious Ham Radio and Radio Monitoring Operators. just $895.00 .8- 1.8GHz $2295.00. Add a 1.3GHz Tracking Generator to any unit 1.3GHz FREQUENCY (OIJN'I'ER .001 ppm $479.00 IS09002 CERTIFIED FIVE YEAR WARRANTEE REG. PRICE $599.00 SAVE $120.00

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Laboratory Performance PROCESSOR STABILIZED OVEN OSCILLATOR .001 ppm Frequency Counter. Accuracy is the #1 Frequency Counter ; t FC1300: the oft, truly Accurate low cost ¡Call 800- 566 -1818 counters being advertised the past few years are but toys when it comes to accuracy. Requirement. The $200 - $800 To Order or Info. 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) 13 GEz, Free 1995 Catalog The FC1300 is accurate to within +/-13 Hz at 1.3 GHz 0-40 degrees C. Sensitivity is < SmV 1Hz to Time Period Averaging, a 50 Ohm & 1 Meg Ohm inputs, LP filter, lx -10x input Att. Frequency Measurement, A l t ANTAGE Interval, External Counter, Freq. Ratio, Hold & Reset Functions, 4 Gate times .01 to 10 Sec. Tired of guess- so -matic Carries a full line of Counters: Serious About Accuracy: Ready to step up to Laboratory Performance Accuracy: Call Today & Order Scopes - Analyzers Frequency Counters INSTRUMENTS CORP. MASTER CARD -VISA - DISCOVER - AMX Generators ADVANTAGE LCR Bridges & DM M'S 3817 S. CARSON ST. # 818 CARSON CITY NV. 89701 Terms: COD - Check - Money Order s 702 -885 -0234 FAX 702-885 -7600 Call Toll Free 800 -566 -1818 - BBS 310-549 -0321 ADD SALES TAX. PRICES & SPECIFICATIONS SUBJECT TO CHANGE HITHOUT NOTICE OR OBLIGATION. F.O.B. CARSON CITY NV. NV. RESIDENTS CIRCLE 150 ON FREE INFORMATION CARD

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CITY STATE ZIP PHONE any company or individual in doing the same. It is not the intent of B &S Sales to defraud any pay television operator and we will not assist 101

CIRCLE 146 ON FREE INFORMATION CARD

www.americanradiohistory.comAmericanRadioHistory.Com HIGH (g:ILIT}' TEST /i,1L7P.lI/.:N'T ALFA ELECTRONIC RI:.tT PRICE DMM 89 $199.95 ALFA 2360 . DMM 2360 DMM 20 Fluke Multimeter Fluke 12 $34.95 Most Advanced DMM $119.95 $74.95 Holster C -10 $10 Att Purpose & rommunrcatior: Inductance: 1µH -40H DAD f+LCR Meter Capacrtance.lpF-2tl)pF Fluke 70 II $67.5 -80.7 to 81.4 iBm with 40 -:2000? F ery I ersatile DMM Frequency: 1Hz-20MHz Fluke 73 II $94 20 reference impedances Volt, amp, ohm, diode, t Fluke 75 II $129 True RMS a Inductance: 1p1-1-40H 20 Amp AC/DC current 1 Holster C -70 Frequency taunter 0.01 Hz -10MHz ... Capacitance: pF -40µF Transistor HFE $16 Frequency - Capacitance: 1 pF- 50,000µF 1Hz 4MH6 Continuity, duty % Fluke 77 II $149 Measure AC colt to 20kHz Temperature: -40-302 F Peak hold /Max Fluke 79 II $169 5000 counts, 0.1% accuracy TTL Logic Test 20MHz Ruggerdized case Rubber holster $8.00 Fluke 29 II $169 Auto/manual range, fast bar graph Diode, Continuity Volt, Amp, Min/Max/Au elDH/R e l a t'v o2 com Ohm Fluke 83 $225 3999 count display Full line of DMMs, Auto power off economy, compact, Fluke 85 $259 Peak Hold Input warning ruggerdized, solar cell Fluke 87 $287 Splash proof OAM COO v0 Auto power off automotive, heavy ( Volt, amp, ohm, logic, diode, continuity Ruggerdized case. duty, industrial Fluke 97 Temperature prrbe included starts from $15.95 Ruggerdized case t $ L-14-14 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 Most Advanced LCR k ip6 Frequency O.1 Hz -1 25GHz Best Resolution LCR Display: 8 digit LCD If Dual display UQ or C/D Period. 0 1µs -0.1 s Inductance: 0.1µ}i -1000H Inductance. 0.1 pH -200H Capacitance: 0.1 pF- 20,000pF Records Max/Min /Average Capacitance:0.1 pF- 10,000µF Data hold, relative mode l Impedance: t m0-10MO Resistance: 1 mO -20MO Telescoping antenna $8.00 1% basic accuracy i 0.7% basic accuracy Deluxe case $5.00 Auto/manual range Dissipation factor indicates leakage Also Available: Dissipation -actor & Q factor in capacitor and O factor in inductor AC /DC clamp meter,Light meter, Zero adjustment to reduce parasitics I Sedal & parallel mode 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, tclerance, $25 00 Force gauge,`rachometer Stroboscope, Humidity & EMS Best for design, incoming LI MI TED QUANTITY SPECIAL adapter, Sound level meter, testing & production o DIGITAL LCR METER $74.95 Frequency counter SWR/field SMD and chip component strength/power meter, Dip mater test probe $25.00 0.1pF, 1µH, 10mQ resolution r 20 MHz Oscilloscope with Delay Digital Storage Scope 0 1 4 I Sweep PS -205 $429.95 DS-203 20MHz, 10M Sample/sec $729.95 Dual Trace, Component test, 8" CRT, X -Y Operation, TV DS-303 30MHz, 20M Sample/sec $E49.96 Sync, Z- Modulation, CH2 Output, Graticule Ilium, 2 probes 11E24_ * 41. each has x1,x10 switch. Best price with delay sweep. DS-303P with RS-232 Interface $10049.96 PS-200 20 MHz DUAL TRACE $339.95 Switchable between digital and analog modes . PS -400 40 MHz DUAL TRACE $494.95 2 K word per channel storage 4t1 1 e ' ' 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 10ms/div - 0.5 s/div v ff44, Scope Probe: 60MHz x1, x10 $15, 100MHz x1, x10 $22 Refresh, Roll, Save all , Save CH2, Pre-Trig 250MHz x1, x10 $29, 250MHz x100 $39 Potter control DC Power Supply DC Power Supply Triple Output PS-303 $159.00 PS -8202 5499.95 , 0-30 VDC 0-3A output Two 0-30 VDC , 0-3A outputs Constant voltage & constant current node One fixed 5VDC, 3A output 0.02% + 2mV Une regiaton Capable of independent or tracking operation 0.02% + 3mV load reglator Constant voltage and constant current mode 1 mVnns noise and ripple Four digital meters for volt and current display Short circuit and overload protected r- Excellent regulation and low npple PS -8200 with digital voltmeter $179.00 Start circuit and overload protected Also available 30V/5A, 60V/3A, 60V/5A Also available: 30V/5A triple output $540 95 16V /lOA, 30V.'tOA. Dual tracking 30V/3A, 30V/5A, 60V/3A, 60V5>

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 10Hz - 1MHz in 5 ranges $119.00 Output 0-8Vrms sinewave Sine, square, triangle, pulse and ramp 100 kHz- 150MHz sinewaye in 6 0- 10Vp -p squarewave Output 5mV- 2OVp -p ranges Synchronization. +3% of oscillation 1% distortion, DC offset + 10V RF Output 10CrnVrms to 35 MHz frequency per Vrms VCF: 0-10V control frequency to 1000:1 Internal 1 External kHz, 50Hz -20kHz Output distortion. AM modulation FUNCTION GEN /COUNTER 0.05% 500Hz - 50kHz Audio output 1 kHz, 1 Vrms 0.5 % 50Hz - 500kHz FG- 2102AD $229.95 Output impedance: 800 ohm Generates signal same as FG -2100A :i>nts::t...a;e,Ï:arn.cz.t 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 GEN. /COUNTER $329.95 $229.95 0.5Hz to 5 MHz in 7 ranges Generates PF signal same as Generates audio signal same as Sweep: Linear 10:1/Log 10:1 20ms to 2s SG -41608 AG -2601 A AM Modulation 8 digit frequency counter 1Hz - 150 6 digit frequency counter 1Hz- Gated Burst, Voltage Control Generator MHz for interna: and external 150MHz for internal and external Generator Control Voltage & 6 digit counter 75.y'u -KY source Sensitivity <50mV sources Sensitivity <50mV 1 Hz -10MHz for internal & external sources

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INCLUDES STROBE The Exciting New Laser Pens 2 AAA Batteries LIGHT MONITOR Pen Size: 5112' x 1/2" Do you need TELEPHONE an attention 4mW getter, warning light,or flashing Beam visible up to 500'. SUPER light for model NEW LOW PRICE airplanes? Then this kit is for you. DANGERM Use it as an emergency light for your auto, radio tower, even use it on your Lam RadWan AVOID DIRECT flash rate. EYE EXPOSURE bicycle. Has a variable Monitors your phone system, Law radiation u emitted from Size 3.5'x1.8' operates on 6 or 12v M. APERTURE See how accurate your phone LASSE DIODE W...S St Vaal DC only. Iv Ou W 4MW CLASS nÍA company really is! LASER PRODUCT ST -1 $9.95 1. RECORDS OUTGOING CALLS : MICRO -MINIATURE MICRO- MINIATURE Date & time of each call. WIDE BAND WIRELESS PREAMP PHONE MIKE Length of the call. The ideal preamp TRANSMITTER So small you could What number was dialed. for scanners, hand We haven't seen a smaller fide this one on some If you use a credit card it records held radios, fre- phone transmitter than the real bugs! It's the the card number. quency counters. MMPT2 kit. Powered by smallest we've ever the phone, it requires no 2. RECORDS INCOMING CALLS : Amplifies low level seen. With its super sensitive mike it trans- battery. Transmits bo h sides of a phone conver- mits a whisper or a room of conversation to an Date & time of call. (weak) signals. If he signal is extreme- a 1/4 mile sation to an FM radio up to FM radio, tunable from 88 to 108MHz FM. How many times phone rings. FM. Attach it to ly low 2 amps can be used in series. away.Tunable from 88 to 108MHz With a proper antenna & 9v it transmits about one phone or add it to the line lo pick up all If answered the length of call. 1MHz to 2.5MHz © 2.8dB of 1dB com- 1 mile. The kit is made with surface mounted incoming calls. The MMPT2 is undetectable if pression = +0 dBm gain: 1 MGHz -20dB parts, we have already mounted these parts. 3. RECORDS ANY DTMF TONE : properly installed. Unit has surface mounted parts, 12vDC ® 16Ma You install the leaded parts. Can operate on 6 on line sent by to 2.5Hz -6dB Requires leaded parts.Size .45x.6' Detects any tone you install the to 12v DC. Size .35'x.9' phone company or any other source. WBA-6 $19.95 MMPT2 S29.95 MMWM5 $34.95 Records to Screen or Floppy Disk WIRELESS FM TV NOTCH FILTERS MICROPHONE 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 eliminate unwanted Phone line out to telephone. & units many times its SNOOP TV channels or All software included! price. It really BULLET interference that alters both a The WM -1 kit is a stomps out signal. sound and video with a buffered wireless m'ke that operates from beep - beep - beep. 80MHz to 120MHz FM , the frequency of TM-1 ONLY KIT any broadcast FM radio. Includes a mini - NOTE: All TV Filter Kits are sold for educational purposes only. You must obtain permis- $9995 electret mike. SIZE:.8'x11 6 to 12vDC sion from your local cable compaiy before using these filters on your cable system. WM -2 $14.95 DF -222 Kit $14.95 BUILT$16995 FM STEREO This Manual contains all TRANSMITTER 5.0 mW Laser Diode schematics, parts lists , P.C.B., MI! Own your own FM radio for making a Rainbow station. Any stereo signal Great layouts for most of the sight, use as a you plug into the FMST- gun Kits. Use your own parts to transit, makes a 100 will be transmitted to any of our kits. any FM radio tuneable super experimenters construct link project. The beam is T01 from 76 to 08MHz FM. Transmit a wireless avµ,y Uv through an auditorium, from your car to your visible with a wavelength of 670 nm. Size of ARa.+ KIT BOOK camper, listen to your cd's while mowing the beam is 6mm at 5 meters. Operates on 3 lawn,Play music on one channel sing on the other. volts DC at 85mA. Size: 10.5mm x 18.5mm $14.95 Clarity is excellent, aprox. 40dó stereo separation. with an adjustable collimating lens. Length of antenna determines the distance of i $9.95 with the purchase with stereo input level transmission. Complete LDM-5 of any kit. controls , & crystal for stereo separation. 9v battery operation 4G FMST -100 / FMSTC cabinet $8.95 $29.95 Please add sufficient postage First /b $5.00 Canada $7.00 PHONE SUPERSNOOPER 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 VISA. batteries. Transmits a parabolic reflector and hear blocks both sides of a phone 317- 291 -7262 away. The BIG EAR can be iidden about conversation loud and clear, wireless, to any anywhere. Makes an ultra sensitive inter- FM radio at great d stances. Variable tunes com. Can be used as a 1.5W AMP. We from 70MHz to 130MHz FM. You can also supply a mini -electret mike in the kit. RAINBOW use it as a speaker phone. SIZE .5'x1" (ELECTRONIC SIZE: 1'.x.75" 6 to 12vDC . TEL -B1 $12.95 AA -1 $10.95 6254 LaPas Trail Indianapolis, IN 46268 FAX 317 -291 -7269 103 BUILT S29.95 BUILT $29.95

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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 Delayed Sweep S -1365 $849 Cursor Readout 40MHz DUAL -TRACE

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V -660 - 60MHz, Dual Trace $1,375.00 Autoset, automatically V -665A - 60MHz, DT, w /cursor $1,449.00 sets voltage, time & trigger Dual Trace $1,549.00 V -1060 - 100MHz, Multimeter display; V -1065A - 100MHz, DT, w /cursor $1,695.00 Plotter 2K Word Per Channel Output 3 -2/3 digits ( >3000 counts) V -1085 - 100MHz, QT, w /cursor $2,125.00 8 Bit Vert. Resolution 2048 Pts Hor. True RMS volts; AC or - 100MHz, Digital Stor CALL VC -6045A $749 Resolution Much More AC +DC up to 600V VC-6025A - 50MHz, Di ital Stor CALL GUARANTEE CALL TOLL FREE I=1, 15 DAY MONEY BACK C &S SALES INC. FULL FACTORY WARRANTY NEW 1245 ROSEWOOD. DEERFIELD. IL 60015 1-800-292-7711 ALL PRODUCTS ARE FACTORY 520 (708) 541 -0710 RHICLS ! UHJI C- W CHAN°, 1"111,IU111 N11111:t. FAX 708- -0085 1- 800 -445 -3201 (Can) pro 105 CIRCLE 32 ON FREE INFORMATIOk CARD

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PERSONAL DEFENSE ALARM 3 1/2 DIGIT PANEL METER DIGITAL POCKET MULTIMETER

Violent crimes are on the This meter has many 3 1/2 Digit LCD Display - increase don't take useful applications AC & DC Volts chances! Loud noise is such as Voltmeter, DC Current your best defense! This is Thermometer, Dl> This little gem comes with the loudest personal alarm we Meter, Watt Meter, many fancy features consid- have ever tested! It is a secu- Current Meter, Capaci- ering its compact size! Light rity alarm designed to be tance Meter, Lux Meter weight and hand held, this yourdiscreet companion and and L(R .Meter. unit also tests batteries and protector. The 130dB alarm is Features include: 200mV fullscale input sensitivity, single 9VDC diodes. Great for the techni- activated by pulling the pin operation and decimal point selectable. In addition, it hos 13mm figure cian, student and hobbyist out on the cord. Alarm will continue to sound up to 2 hours (with a height, automatic polarity indication, guaranteed alike! fresh battery) until the pin is reinserted. The de!aMahle d4 on the bads zero reading for 0 SPECIFICATIONS: DC

akws alum to be anadred to pose, bat, camera bag or pocket. Uses 9v volt input and high input impedance ( >100M ohms). Specifications: Volts: 2 -500V, AC Vohs: 200 -

battery (not Mulled) WARNING - Nam B so laud B may damage ears with Max input 199.9mV DC-Max. Display:1999 counts (3 -1/2 digits). 500V, DC (errent: 200mA, Resistance: 21(- OHMS- 2MEG.ONMS, carlinuous exposure. Makes a great gift for ,okryr loved ones. Measures Measuring method: Dual slope integration A -D converter system, plus Diode Test: 3.2V Mox 1 =1mA (Diode), Battery Test: 1.5V AA

21/1 "x 1 1/4" Bkudk. Order now! cur aron 1 $11.95 each many other features cura PM -i $17.00 mach (40mA)- 9V(24mA) urroau-or $19.95 each

STEPPER MOTOR CONTROLLER KIT STROBE KIT BREADBOARDS

This allows kit you to This kit allows Breadboards allow you to design adjust the speed and you to vary the and prototype circuits quickly. It direction a of stepper rate of strobe lets you position components on motor. you can move the flashes 60 to the board without soldering. motor in one step incre- 120 flashes Great for the experimenter, student ments or rotate it at a per minute. and hobbyist! This breadboard constant speed. There Operating volt- is a large size board with are a of visual set indica- age is adjust- enough room to design major tors that show the able depending projects. It measures: 7" x 9" sequence of motion. Includes stepper motor, oc board, parts and instruc- on how you wire the kit. It will work on 4.5, 6 and 12 UDC. Includes and has 4 terminal strips, 1 distribution strips, and 4 binding posts tions. (12vdc power source not included.) urrsaxt $25.00 mach pc board, parts and instructions. currsrx -r $7.50 each mounted on an aluminum back plate. curiae 7 $35.00 each

CAMCORDER VIDEO TAPES BACK -FORTH FLASHER KIT DC MOTOR SPEED CONTROLLER KIT

HI -8 120 MINUTE WOW! Easy To Build! VIDEO CASSETTE An Eye - This kit allows you to con- TAPES (used) Catching trol the speed and direction They were recorded on Delight! of a 6 to 12 volt motor. It once and played only a Great for is easy to build and few times. Made by a special effects includes pe board, motor, major brand nome manu- and other ports and instructions. facturer. Professional high -tech series metal tapes. Req ires one err cr 1 $3.00 each applications. Includes plastic jewel box. 10 or more 2.80 each 9V battery (not i (111# - eluded). 10-01 $6.50 each cureesc -: $15.00 each REGULAR CAMCORDER TAPE PRINTED CIRCUIT BOARD TRANSFER FILM CALL TOLL FREE! 120 MINUTE VIDEO For LASER 1- 800 -526.3717 CASSETTE TAPE PRINTERS And (used) PHOTOCOPIERS 1. California residents must include sales tax. 2. Pay by check, money order, Visa or MasterCard. NO CO.D.s. Major brand name manu- Eliminate darkrooms, 3. Ouanties limited - prices subject to change without notice. facturer, recorded on once photochemicals, neg- 4. Add 53.50 shipping 8. handling charge on all orders. and played only a few atives, and copy times. Excellent condition! cameras! Make print- Black Feather These will play on a ed circuit boards regular camcorder, where the HI -8 tapes don't. If you have a regular using a laser printer camcorder machine then this is the tape far you. If you have an HI -8 or photocopier, direct AMIr Ai. Al& AL. AL machine, you may enjoy the higher quality provided by the HI -8 from CAD software or tapes. Includes plastic caner -z s2.50 each magazines. Only four easy steps: 1. Print CAR TB( -i $10.95 645 Temple 7B A Long Beach A California 90814 jewel box. 10 or more - 2.30 each or copy; 2. Iron -on; 3. Peel -off, 4. Etch! Package of 5 A (310) 434-5641 A FAX (310) 434 -9142 A

www.americanradiohistory.comAmericanRadioHistory.Com Established 1945 (800) 645-9212 70 Minimum M/C & VISA K E L V, I N (516) 756-1750 Order L E TR NI KELVIN CATALOG $3 (516) 756-1763/FAx Stock No. 650412 1014.UB DRIVE. MELVILLE NY 11747 Standard Features AC & DC VOLTAGES DC CURRENT RESISTANCE CONTINUITY TESTER - Buzzer DIODE TEST 10M ohm INPUT IMPEDANCE ACCURACY +I- 0.5% RDG TRANSISTOR FREQCOUNTER AUTO INDUCTANCE up to 20MHz RANGE Rowl1uH BATTERY TEST FFuRREQ OUNTER with 3200 counts DC CURRENT CAPACITANCE from 1 pF to 20uF AC CURRENT CAPACITANCE 10 Amp TRANSISTOR DC CURRENT front 1 pF to 200uF ANALOG BAR AC/DC CURRENT ACIDC CURRENT TRANSISTOR 10 Amp 10 Amp DUTY % 20 Amp 150 LE 200 LE 300 LE 400 LE Stock # 990122 Stock # 990123 Stock aI 990125 Stockar 990124 $2995 40D LE - Engine $7995 150 LE - Student 200 LE - Technician 300 LE - AutoRange $4995 $4995 UL -1244 KELVIN CAPACITANCE Designed to meet IEC -348 & 100 Basic KELVIN METER Rcafions. 250 LE $ÇQ95 990087 $1995 Protective Cases f# 990126 J For Models 100 Basic, 150LE, 200LE, 300LE AC&D 0.5% ACCURACY VOLTAGES RANGES:2omF, 54.95 (4990088) DC CURRENT 2000uF,200uF,20uF, RESISTANCE 2uF, 200nF, 20nF, Case For Model 400LE 59.95 (#990116) 3 1/2 Digit LCD 2000pF,200pF CONTINUITY TEST Zero Adjust -Buzzer Safety Test Leads 2 Year Warranty LOW BATTERY INDICATOR Test Socket for DIODE TEST BATTERY TEST Plug -in Components

I The Ultimate Meter TRUE RMS - LCR - Hz - dBm

At tr nW wMr O Popular tíec1lULtlt k6evewec o,1ay 4*4 11UTP nH "Not only does the Kelvin 94 boast alot of features ... the features go the extra ynF latit " distance." kMD 1 MwYi . "li we had to run into a burning building to do some emergency troubleshooting and . . J. . MkH: it!" 30 40 could carry in only one piece of equipment, the Kelvin 94 would be g: .

4-041111114111110111111111111111111111A 12 INSTRUMENTS IN ONE - DC VOLTMETER, AC VOLTMETER, OHMMETER, AC CURRENT, DC CURRENT, DIODE TESTER, AUDIBLE CONTINUITY */iVO AE/MN/N6 RELATIVE NC/AC TESTER, dBm, FREO COUNTER, CAPACITANCE METER, ® NDUCTANC'E METER, LOGIC PROBE Hz OFF IÄ r 400o 4 to AUTO SLEEP & AUTO POWER OFF tl 0.1% ACCURACY BUILT -IN TO SAVE BATTERY LIFE 4$7 g011 IZ ON DC VOLTAGES war, 41A with Bypass 750^,

401 TRUE RMS ON AC VOLTAGES & CURRENT SHOCK RESISTANT 400. HEAVY DUTY CASE WITH 40. 4M YELLOW RUBBER HOLSTER FREQUENCY COUNTER A 4. 40M & TILT STAND TO 20 MHz 400aM WATER RESISTANT SEALED CASE 40er LARGE EASY -TO -READ 4004°40.014:104µF400eF 3 3/4 DIGIT LCD DISPLAY LX ÿ1i 30 DAY MONEY BACK auto SATISFACTION GUARANTEE power off ( LCRHzdBm 95 A uAmALE V-S211z-Cx MODEL 94 0.1:. ACCURACY Water 9990111 on DC Voltages Resistant 4U0mA $199 MAX Usto A\ COMES COMPLETE WITH MAY HOLSTER, PROBES, Freq Counter to 20 MHz I 7511v-ii YELLOW UNWSEO BATTERY, FUSE, STAND -®104 MAX KELVIN TRUE RMS ""ç 94 Cases for Model 94 Meter is designed in Protective with safety 59.95 (#990116) accordance Regular Padded Zippered requirements specified in Padded Zippered 514.95 í#9901i5) I EC-348, U L-1244 V D E-0411. Deluxe 107

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Worlds smallest FM transmitter. Use with any FM Worlds smallest FM phone transmitter. Use with any When the XBD200 intercepts a signal in the 1 to 2,000 Separate left and right inputs and gain controls Include=-- an broadcast receiver. Easy to assemble, all chip (SMT) FM broadcast receiver. Easy to assemble, all chip com- MHz range, it emits a growl that increases to a high output booster stage for greater range. parts are pre -assembled to the circuit board. ponents are pre -assembled to the circuit board. pitched squeal as the signal strength increases. XFS -CASE KIT 13.95

XST500(E-Z)Kit $44.95 XSP250(EZ)Kit $34,95 XBO200 C Kjt $49.95 XFS108 C KIT $41.95

Dial your phone from anywhere Transmits a continuous beeping tone. Works with any FM broadcast receiver Use with any FM roadcast receiver. and listen to the Turns when is not in sounds Adjustable from off phone use to Hear every sound in an life. inside your home. 88 to 108 MHz. extend battery entire house! Two digit Touch Tone from 8810 Up to 1 mile range. Up tot mile range code for secure operation. 108 MHz. `+r Works with any FMt Powerful 2 stage te. 1 mile r¡rf t TELEPHONE SNOOP broadcast receiver. range. audio amplifier. The latest in home or office security. Call home from any - where, enter a two digit searity code, and hear the sourds in TRACKING TRANSMITTER L OIIG RANGE PHONEI E 1 RAMSMIT 1ER TURE RN TRANSMITTER your hone Automatically turns on without ringing the Worhe, Only 0.7 by 24 inches, the XTR100 operates at voltages of 3 Similar to our very popular XSP250, the X17100 is battery The XFM100 has a super sensitive microphone and is verifies code. then activates for one and a half minutes to 1B Volts and is ideal for use in locating lost model rockets, powered for greater range. It plugs into any phone jack and capable of picking up sounds at the level of a whisper XPS-CASE KIT $13.95 bicycles, automobiles, games of hide and seek, and contests. transmits both sides of conversations on that line. and transmitting them to any FM broadcast receiver

XPS1000 C KIT 9.95 XTR100 C Kit $33.95 XTT100(C)Kit $32.95 XFM100(C)Kit $32.95 Digital voice changing. male to female Digital voice changing: male to fe- Uninterrupted coverage of 800 Works with most any scanner. female to male, adult to child, child Ji male, female male, to adult to to 950 MHz. 10 TO 1000 MHz to adult. child, child to adult. Works with any scanner that Anonymity 10 dB typical gain. on any call. Use with any modular phone. can receive 400 to 550 MHz. dB typical noise figure. Button for normal operation 16 levels of voice masking. 3 800.950 MHz SCANNER CONVERTER KIT 10 -1000 MHz AMPLIFIER 16 levels of voice masking. 'v. Connects between handset and phone. If your scanner can receive 400 -550 MHz, just add Designed to help scanners with poor sensitivity pull VOICE CHANGING TELEPHONE VOICE CHANGING ACCESSORY the XLC900 for ugipterruolfd 800 -950 MHz cover- in those weak signals. Includes OFF /BYPASS switch age. It converts all 950 Hz signals down to 400- for returning to normal operation and front STOP THOSE ANNOYING TELEPHONE CALLS! Sound STOP THOSE ANNOYING TELEPHONE CALLS! Sound panel 550 MHz so your scanner can receive them! Add our gain control. Add our custom case kit for that 'Pro- older and tougher when you want to. Not a kit. Fully older and tougher when you wam. to. Not a kit. Fully custom case kit for that 'Professional' look. fessional" look. assembled. Single phone operation only. assembled. Use with single or multi -line phones. XLC -CASE KIT $13.95 XLA-CASE KIT $13.95 TRANSITION2000 $89.95 TRANSITION 2001 $59.95 XLC900 C KIT $49.95 XLA1000 C KIT $24.95

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As seen on CBS '69 Mlnules' $350 000 ATM crime scree still unsolved' $39. Forbes, etc. By John Williams - former Lockheed Senior 18 "x18"x4.6" WORK AREA Engineer, NMSU Computer Science Professor, NIH Health CREDIT CARD SCAMS Physicist Wanted: 9 MAC tic!, PC388, bener buy. bade, and odors, mere ants, .an sullen ms A11 eoftwere supports ell IBM -PC corm losses annually because of credit card fraud. -Describes Ohre wee a stems eoee Pentium every known means of credit card fraud and scams. Off -The-Shelf HARDWARE Protect ourself! $29. THIS IS THE MACHINE YOU'VE BEEN WAITING FOR! CONS SCAMS & SWINDLES 'an c yystem, raa ar. ea. ec "rter, ' Have you ever dreamed of letting your computer manufacture products directly from KX Radar Emitter, Street Sweeper (radar), Lidaro, one : scams an. relate. swin. es eece encans o your CAD drawings? If so, the Neuractor CNC Desktop Manufacturing CarjackKidnap Feller, Voice Disguiser, Hearing As- $100+ Billion per yead The most comprehensive sur- -4+ System may vival manual on cons slslor, Shriek Module, EM Lab 8 Countermeasure. & scams of all kinds - from the be just the edge you need! This fourth -generation CNC machining center can classic to hi- tech. Petals on 100s and their many vada- TENS, 6th Sense Communicator, Phone Color Bau, automatically drill, mill and route three -dimensional products in lion s and countermeasures. Protect ourself! $39. wood, plastic and light Lineman's Handset, DTMF Decoder, Bug 8 Tap De- metals DIRECTLY FROM YOUR CAD DRAWINGS! You've seen lectorHiasfer, Subliminal Mixes/imp. Neurophone' STEALTH TECHNOLOGY the rapid- prototyping RIfeHleronymueHesanant Crystal Radionlc. 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Destruceve to people, animals, lants, VOICE MAIL HACKING equipmenti Includes ACTUAL LASES OF EM_ATIPACKS DC/CAD o1LPEOPLE_ we Invesligated)I Includes how to verify How Vo ce Mall Box ( M r) systems are used an. the arid pinpoint EMI and electronic attack sources, and spa-spa - specific ways they are hacked. Includes ASPEN, MES- Z)tITOducing. . . clec countermeasures. SAGE CENTER, BIX, GENESIS. E2, SYDNEY, PHONE $29. Et'1_ @RAIN @LA.$T Tutorial and plans for powerful ELECTROMAG- MAIL, AUDIX, CINDY, CENTAGRAM, SPERRY LINK, ER: NEIIC WEAPONS and LAB DEVICES. Optimum circuits, RSVP, etc. Absolutes re wired for all users, s so sand y tregs, waveforms. duty cycles, Intensities. Thorough. secud ersonnell $29.q p THE TERMINATOR 29. Both 49 RADIONICS MANUAL Super High Density Router s o s are ac xe to t le ne of on c rag electrical, electronic, electromagnetic therapeu- (Complete with Schematic While 'VOICE MAIL HACKING' details how VMS5 are & PCB EDITOR) tic,tic diagnostic & preventive devices experineen- for'phun' and profit including VMS methods (mostly History, descriptions, plans (dozens), avallabilbiee or hacking PBXs themselves - 'PBX HACKING' ad- of Radlonlu Devices from early to modem Willie Features the following powerful algorithm & capability: dresses ALL Issues relating to PBX hacking, Including drugs cost S Hundreds, electricity casts pennlesl $29 countenneasuresl Can your business or agency afford a HEAL Plans for J major electronic therapeutic Rip - up and Retry 590,000 phone fraud loss ((the average loss due to THYSELF' devices oft .es a.. roved b FDA. $19. Both $39. hacked PBXs 7 As described In Forbes Mai azina. $39 Pre- routing of SMT components PHREAKING CALLER ID & ANI B an ORDER of the MAGNITUDE a most compre ens ve, art- tt n5, - ec sur- Tear s on ow a wo an..ozens o e'ec ive ways Real -Time via minimization rival book ever wrltlenlpp Topics Include electronics, ol deieatlng Caller ID, ANI, '69, '57, and Call Blocking and 67, Also describes Caller ID, Orange, Beige, aarrmsln toenerrvive today's 'dangerous worldeWegali Real -Time clean up passes Cheese and CF Boxes, ESS, SS7, E-911, various c lace Increasingly Ilnancialty and physically brutal tlrnesl CLASS services, Ct47+, NON PUB DA, CAMA. MR, Field- expedient use of technology n various threat and User defined strategies 800 -ECR DIverters Extenders Centrer - more. $29. conflict environments and scenanós. $49. Be and PHONE COLOR BOXES CRYPTANALYSIS TECHNIQUES Window 3.0 capability as DOS Task sows p one co or .oxen .-sc .e. - many crcuits. 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Sknpte time, whether busy or answered (your choice) and log Optional simulation capability and automatic to Install on your distributed software. & protected mode for 386 users the times, commands and results to monitor, printer Compatible with all other copy -prevention systems. and -or Quick -dial directory of up to BOG numbers disk Manual + Disk' $59. BUSY redial options. Direct modem command and con- * PCB LAYOUT SERVICE AT LOW COST * trol. All Result Codes, Including VOICE and RINGING. ROCKET'S RED GLARE Optional shell to terminal pro.ram upon CONNECT. Exit 'ow o .es gn an. ,u . s . -prcpe ant ama eut an. LEASE PROGRAM & ShIL LICENSE AVAILABLE to menu or DOS for batchlro . Manuel + Disk' $29. survival rockets. Emphasis on formulation, manufacture, Installation of propellants, motors, Igniters. etc. Includes COMPUTER PHREAKING Ilsl of commonly available materials, and the design of Ie n .e sett. es ai ow compu ers pene a e eac o er, launch pads and test beds and their electronics. $29. and how VIRUSES, TROJAN HORSES, WORMS, are etc FIREWORKS: How firecrackers (M -80s, biockhust- Implemented. Dozens of computer and crime abuse ens, cherry bombs), small rockets, voicanos, lourilalna, methods and countermeasures. Includes disk filled with spadders and safety fuses are made and colored. hacker text flies and utiiltlee, and the legendary FLU- Sim le chew common In redlents. $9. Both $36. SHOT+ protection system (Ed. Choice, PC Magezlne). Design HS advice, password defeats, glossary - much morel Manual + Disks' $39. n erpa d arasse or a used an pu me Computation taken for granted? Stuck In a dead -end job? Can't find a Beyond VAN ECK PHREAKING 17'71 good job? Expect to be laid off, fired or transferred soon? State Hi wayy __34 aves.rnpp n on ' an. compu er e i en s pna s us ra p the ultimate no- holds- barred, optgs aver -w1 Machla- FermineJ 07727 an ordinary I Includes security Industry reports. Helen techniques to find, obtain, optimize and keep top i 9081 681 - 77017 i 9Ó8l 681 - Range up to t KM. Plans Include both the Consumer- 8733 (FAX) jobs, pay and benefits THE RULES OF THE GAME FOR Ironies and the original Top Secret Van Eck designs! A GAME WITHOUT RULES! from resume to CEO. $29. " DC/CAD ... The focal point offuture CAD marker " $29. OrderTodyl rooms 438 -1770

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

Free Information Number Page Free Information Number Page

- A &D Electronics 126 - ITC Microcomponents Inc 111 ADVERTISING SALES OFFICE - A -Plus Electronics 126 ITC Microcomponents Inc 112 Gernsback Publications, Inc. 125 Ace Communications 110 38 Kelvin Electronics 107 500 -B Bi -County Blvd. - Agrelo Engineering 123 M &G Electronics 97 Farmingdale, NY 11735 1 -(516) 293 -3000 26 Alfa Electronics 102 - Marymac Industries Inc. 126 Larry Steckler, EHF /CET 28 All Electronics 98 148 MCM Electronics 125 President Allen Engineering I I2 Mega Electronics - 123 Christina Estrada Allstar Electronics 127 149 Mendelson's 119 Assistant to the President Andromeda Research 125 - Mental Automation 111 For Advertising ONLY Antique Radio Classified 73 42 MicroCode Engineering 108 516 -293 -3000 Fax 1-516-293-3115 Audio Investigative Equip 124 - Modern Electronics 124 Larry Steckler 146 B &S Sales 101 NRI Schools 45,79 publisher - Basic Electronic Supply 116 Northeast Micro 123 Arline Fishman - Black Feather 106 Nu -Tek Electronics 73 advertising director - C &C Electronics 126 Ohio Automation 126 Denise Mullen C &C Specialties 123 PC Boards 112 advertising assistant

132 C &S Sales 104 Phillips Tech 124 Kelly Twist credit manager - Cellsoft 114 145 Prairie Digital Inc 121 - CLAGGK, Inc. CV4,95 151 Print 127 Subscription/ - Cleveland Inst. of Electronics 27 46 Print 113 Customer Service/ Order Entry - Command Productions 121 Progressive Concepts 124 1 -800- 827 -0383 Communication Specialists 126 Rattner North America 119 7:30 AM - 8:30 PM EST - Consumertronics 118 The School of PC Repair 69 - Comtrad 12,23 The School of VCR Repair 69 ADVERTISING SALES OFFICES 14 Cooks Institute. of Elec. Eng 77 Silicon Valley Surplus 126 EAST /SOUTHEAST 162 Davis Instruments 29 Skyvision (Small) 126 Stanley Levitan Design Computation 118 Software Science 124 Eastern Sales 1 Overlook Ave. EDE Spy Outlet 123 Spy Supply 100 Great Neck, NY 11021 159 The Electrician School 71 TAB Books 5,63 1.518 -487 -9357,1 -518- 293.3000 Fax 1- 518 -487-8402 147 Electronic Rainbow 103 Tandy National Parts 93

Electronics Tech.Today 69,83 Tech Sery 106 MIDWEST/Texas/Arkansas/ Oklahoma, Colorado, Arizona 154 Foley Belsaw Institute 65 Tele View Distributors Ill

Forest Electronics 120 UCANDO Videos 122 Ralph Bergen Midwest Sales Fotronic Corporation 117 United Electronic Supply 112 One Northfield Plaza, Suite 300 General Device Instruments 126 US Cable (Zentek) 119 Northfield, IL 80093 -1214 1- 708 -446 -1444 Genuine Electronics 120 US Cable Supply 124 Fax 1-708-559-0582 - Get -Tech Inc. 114 US Cyberlab 113 PACIFIC COAST/Mountain States - Grantham College 3 US Cyberlab 118 Anita Bartman - Great Southern Security 124 Vision Communication Systems.. 115 Hutch Looney & Assoc., Inc. Greenleaf Electronics Inc. 121 - - Vision Electronics 119 8310 San Vicente Blvd. Halcyon Group 113 168 Wavetek Corp. 7 Suite 380 Los Angeles, CA 90048 - Home Automation Systems 125 Weeder Technologies 97 1- 213 -931 -3444 Home Tech Communications 73 Weka Publishing 109 Fax 1-213-931-7309 - Information Unlimited 65 Windward Electronics 120

157 Interactive Image Technologies . CV2 World College (Div. of C.I.E.) 67

Intronics 126 WPT Publications 124

144 Island LogiX Inc 117 134 Xandl Electronics 116

128 150 ITC Instruments 99 Zorin 124

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

Of Leadership in electronics is not 311111, Aerovox° just a matter of designing ue,.nntn products better and DC Film and RFI Suppression Capacitors, Aluminum manufacturing them better, but Fixed Ceramic Capacitors, Variable Capacitors and Electrolytic and AC Oil Capacitors, EMI Filters Dade Electronics, Inc. Resistors, Crystal Oscillators, Ceramic filters, also marketing them better. Resistors. Networks, Oscillators, Displays, of Resonators. EMI Filters, Hybrid Circuits and more. Inductors, Thermistors, Connectors, & And the sponsors of this Transformers AMP message understand that better LwyppircifivA Panasonic Electrical /Electronic Connectors, IC Sockets, Industrial Company service to customers requires 1 INDUSTRIES, 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 Antennas: Cordless Phone and Scanner Resonators, Varistors, Thermistors M teams. RAI) Lngincering, Inc. DEARBORN Motor Run Capacitors, HID Lighting Capacitor, W IILE ANI) CABLE L.. Imo. Philips Components Distributor involvement means 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 Subminatuse Coaxial & Military Controls Operation Distributors help achieve Connectors and Cable Assemblies. through Switches, Relays, Displays and Keyboards distributors. marketing leadership. So does /AVM( CORPORATION the manufacturer's involvement

in the Components Group of MLC, Tantalum and Thin Film Capacitors, Resistors, They belong Networks, Integrated Passive Components, ELECT ONiCs the Electronic Industries Trimmers, Oscillators, Resonators, Filters, Pieto Quartz Crystals, (lo k Oscillators, Surface Mount to the E.I.A. Devices, and Connectors Products, Programmable Devices Association. EIA fosters better They belong industry relations, coherent industry standards, and the BERGLrCrR,,NIC, GERNSBACK on your sharing of ideas, which helps High Density and Industry Standard vendor list. Now Magazine one another and serves Connectors/Subsystems Electronics customers better. CAROL Quam 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 Relays and Solenoids ROHff1 leadership -- KEMET Rohm Electronics Division Resistors, Ceramic Capacitors, Electronics Corporation availability through distribution Transistors /Diodes, Opto Components and IC's

Tubing, Conduits, H se, Sleevings, Splices, Multilayer Ceramic and Solid Tantalum membership in E.I.A.

Insulation and Cable Harness Products, Power Capacitors Cords and Cordsen w SEIECTA Our (OA1 SPEER Switches, Relays, Terminals, Indicator/Pilot 70th .H M Instruments Inc. Lights, LED Indicators, Test Chps, Test leads, Cn Midtex Resistors, SMT Tantalum Capacitors Inductors, Anniversary Cable Ties and Heat Shrinkable Tubing Resistor Networks, SMT Thermistors Relays and Solenoids Year

mow Electronic Industries Coog-R MALLORY Association/Components Group Pennsylvania Avenue, N.W., Bussmann North American Capacitor Company NuE 2001 Tantalum Capacitors, Wet O Foil Capacitors, 11th Floor Fuses, Fuseholders, Fuse Blocks, and Fuse Tantalums, Aluminums, SonalteroR Ceramics, Resistor Networks, Resistor Capacitor Accessories Films and AC's Washington, D.C. 20006 Networks, Filters Phone: (202)457 -4930 CORNELL iWitcharan Fax: (202) 457 -4985 A IlaylMUP Company DUBILIER M-tron Committed to the competitiveness Plugs, Jackhelds 8 Capacitors -Aluminum Electrolytics, Mica, Quartz Crystal Switches, Connectors, Jacks, of the American electronics Hybrid Oscillators Audio Accessories, Cable Assemblies AC Oil, Film, MICA Paper and Relays producer.

www.americanradiohistory.comAmericanRadioHistory.Com Countersu rvei nance

Never before has so much The professional discussions seen on professional information on the art the TV screen in your home reveals how of detecting and eliminating CALL to detect and disable wiretaps, midget electronic snooping devices radio -frequency transmitters, and -and CpNN1EN- other how to defend against experienced NOW! bugs, plus when to use disinformation to SNMEIEEANCE information thieves -been placed 111" confuse the unwanted listener, and the in one VHS video. If you are a 10, TECNNIQNESs technique of voice scrambling telephone Fortune 500 CEO, an executive in communications. In fact, do you know any hi -tech industry, or a novice how to look for a bug, where to look for a seeking entry into an honorable, bug, and what to do when you find it? rewarding field of work in Bugs of a very small size are easy to countersurveillance, you must build and they can be placed quickly in a view this video presentation again matter of seconds, in any object or room. and again. Today you may have used a telephone handset that was bugged. It probably contained three bugs. One was a phony Wake up! You may be the victim of bug to fool you into believing you found a stolen words -precious ideas that would bug and secured the telephone. The sec- have made you very wealthy! Yes, profes- ond bug placates the investigator when sionals, even rank amateurs, may be lis- 1- 516- 293 -3751 he finds the real thing! And the third bug tening to your most private con- is found only by the professional, who versations. HAVE YOUR continued to search just in case there were Wake up! If you are not the victim, VISA or MC CARD more bugs. then you are surrounded by countless vic- AVAILABLE The professional is not without his tims who need your help if you know how tools. Special equipment has been de- to discover telephone taps, locate bugs, or what was to be an embassy and private signed so that the professional can sweep "sweep" a room clean. residence into the most sophisticated re- a room so that he can detect voice -acti- There is a thriving professional service cording studio the world had ever vated (VOX) and remote -activated bugs. steeped in high -tech techniques that you known. The building had to be torn Some of this equipment can be operated can become a part of! But first, you must down in order to remove all the bugs. by novices, others require a trained coun- know and understand Countersurveilance tersurveillance professional. Technology. Your very first insight into Stolen Information The professionals viewed on your tele- this highly rewarding 'field is made possi- The open taps from where the informa- vision screen reveal information on the ble by a video VHS presentation that you tion pours out may be from FAX's, com- latest technological advances like laser- cannot view on broadcast television, sat- puter communications, telephone calls, beam snoopers that are installed hun- ellite, or cable. It presents an informative and everyday business meetings and dreds of feet away from the room they program prepared by professionals in the lunchtime encounters. Businessmen need snoop on. The professionals disclose that field who know their industry, its tech- counselling on how to eliminate this in- computers yield information too easily. niques, kinks and loopholes. Men who formation drain. Basic telephone use cou- This advertisement was not written by can tell you more in 45 minutes in a pled with the user's understanding that a countersurveillance professional, but by straightforward, exclusive talk than was someone may be listening or recording a beginner whose only experience came ever attempted before. vital data and information greatly reduces from viewing the video tape in the pri- the opportunity for others to purloin vacy of his home. After you review the Foiling Information Thieves meaningful information. video carefully and understand its con- Discover the targets professional r tents, you have taken the first important snoopers seek out! The prey are stock CLAGGK INC. PE step in either acquiring professional help brokers, arbitrage firms, manufacturers, P.O. Box 4099 Farmingdale, NY 11735 with your surveillance problems, or you high -tech companies, any competitive may very well consider a career as a coun- industry, or even small businnesses in the Please rush my copy of the Countersurveillance Techniques Video tersurveillance professional. same VHS Cassette for a total cost of S53.9S each (which community. The valuable informa- includes 54.(X1 postage and handling). tion they filch may be marketing strat- No. of Cassettes ordered The Dollars You Save egies, customer lists, product formulas, Amount of payment S To obtain the information contained in manufacturing techniques, even adver- Sales tax (N.Y.S. only) the video VHS cassette, you would attend tising plans. Information thieves eaves- Total enclosed Bill my VISA MasterCard a professional seminar costing $350 -750 drop on court decisions, bidding Card No. and possibly pay hundreds of dollars more information, financial data. The list is Expire Date f if you had to travel to a distant city to unlimited in the mind of man-es - Signature attend. Now, for only $49.95 (plus pecially if he is a thief! Name $4.00 P &H) you can view Countersur- You know that the Russians secretly Address veillance city State ZIP Techniques at home and take installed countless microphones in the refresher views often. To obtain your concrete work of the American Embassy All payments in U.S.A. funds. Canadians add 54.(X1 per VHS cassette. No foreign orders. copy, complete the coupon or call. building in Moscow. They converted L J