Popular Onics

ElectrJanuary 1995 Popular onics

Simulator Use iTO est te ep ones, answering machines, Fax machines, and more

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www.americanradiohistory.comAmericanRadioHistory.Com JANUARY 1995 Vol. 12, No.1

A Popular Electronics GERNSBACK TPUBLICATIONCATION 1

C O V E R S T O R Y

31 Build a Telephone-Line Simulator A complete telephone- system -in -a -box; you can use this telephone - line simulator to test telephones, Fax machines, answering machines, and more, or set up your own simple two- station phone system - Thomas E Black

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

49 Build a Simple WWV Receiver Page 9 Get time, weather, frequency, and other information whenever you need it -Brian McKean

53 Build a Vacuum -Tube Audio Amplifier Experiment with the warm sound of vacuum -tube audio without putting a dent in your wallet -Larry Lisle

F E A T U R E S

40 A DX Beam -Aimer Program Page 31 Accurately aim your beam antenna with this easy -to -use program - Fred Blechman

45 A Hobbyist's Guide to Surface -Mount Technology The information, tools, techniques, and parts sources you need to make working with surface -mount components easier than you ever imagined -Ronald A. Reis

56 Popular Electronics 1994 Annual Index Your guide to a year of electronics information, projects, and fun Page 53

Gernsback Publications, Inc. 500 -8 Bi- County Boulevard, Farmingdale, NY 1735. Second- POPULAR ELECTRONICS (ISSN 1042 - 170 -XI Published monthly by One -yea twelve issues, subscription rate U.S. and possessions $21.95, Canada Class postage paid at Farmingdale. NY and at additional mailing offices all other countries $29.45. Srbscription orders payable in U.S. $28 84 (includes G.S.T Canadian Goods and Services Tax Registration No. R125166280) Inc. All rights U.S single copy price $3 50.0 1994 by Gernsback Publication:, funds only, International Postal Money Order or check drawn on a U.S. bank Canada by Gernsback Publications, Inc Popular Electronics trademark is reserved Hands -on Electronics and Gizmo trademarks are registered in U.S and is licensed' o Gernsback Publications, Inc. Printed in U.S.A. registered in U.S and Canada by Electronics Technology Today, Inc. and

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

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

www.americanradiohistory.comAmericanRadioHistory.Com J A N U 1 A R Y 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 Apple Computer Newton MessagePad, Oldsmobile Aurora with Carl Laron, editor Dan Karagiannis, associate editor Bose Audio System, California Audio Systems CD Player, and Teri Scaduto, assistant editor much more Evelyn Rose, editorial assistant Marc Spiwak, editorial associate 24 Hands -On- Report Joseph J. Carr, K4IPV, contributing editor Elenco Electronics Telephone -Line Analyzer Marc Ellis, contributing editor Jeffrey K. Holtzman, contributing editor C O L U N S M Don Jensen, contributing editor Marc Saxon, contributing editor 6 Multimedia Watch John Yacono, contributing editor This and that -Marc Spiwak PRODUCTION DEPARTMENT Ruby M. Yee, production director 28 Think Tank Karen S. Brown, Temperature -controlled projects -John Yacono production manager Kathy Campbell, production assistant 64 Antique Radio Tel -Ohmike wrap -up -Marc Ellis ART DEPARTMENT Andre Duzant, art director 68 Computer Bits Russell C. Truelson, illustrator Buy or upgrade? -Jeff Holtzman Jacqueline P. Cheeseboro, circulation director 71 Circuit Circus Michele Torrillo, More ultrasonic circuits - Charles D. Rakes POPULAR ELECTRONICS bookstore

BUSINESS AND EDITORIAL 75 DX Listening OFFICES Gernsback Publications, Helping out the newcomers -Don Jensen Inc. 500 -B Bi- County Blvd Farmingdale, NY 11735 77 Ham Radio 1- 516.293.3000 FAX: 1 -516- 293.3115 A step -attenuator project -Joseph J, Carr President: Larry Steckler SUBSCRIPTION CUSTOMER SERVICE/ 82 Scanner Scene ORDER ENTRY Monitoring VIP military aircraft -Marc Saxon 1. 800 -827.0383 7:30 AM 8:30 PM EST

D E P Advertising Sales Offices A R T M E N T S listed on page 126

3 Editorial Composition by Motes Graphics Cover by Loewy Design 4 Letters Illustration by Kerry Kehoe 80 Electronics Market Place AB ABC 84 Electronics Library AUDITED

86 New Products Since some of the equipment and circuitry described in POPULAR ELECTRONICS

may relate to or be covered by U S 95 Popular Electronics Market Center patents, POPULAR ELECTRONICS dis- claims any liability for the infringement 126 Advertiser's Index of such patents by the making, using, or selling of such equipment or circuitry, and suggests that anyone interested in 127 Free Information Card such projects consult a patent attorney

www.americanradiohistory.comAmericanRadioHistory.Com SURVEILLANCE & SECURITY FM TRANSMITTERS MINI (KITS) 3 -VOLT FM XMTR, up to 300 ft. indoors. 1500 ft. outdoors EDITORIAL PHONE XMTR, range to 500 ft., uses phone -line power Sound -Activated XMTR, range to 500 ft. 2 -STAGE XMTR, 9-Volt, very powerful All above require simple soldering at 2 to 4 places. $29.95" HOBBYISTS AND SMT TELE CALL FORWARDER. Transfers incoming calls. $99.00` CALLER ID. Registers incoming number. By now, most readers of this magazine are familiar with $99.00' in electronics assembly called "Surface - TEL REGISTER WITH PRINTER. Records dialed the revolution number, duration, and prints record. $169.00' not, and if you are like Mount Technology." If you are TEL REGISTER W/O PRINTER. Records dialed most hobbyists, let me tell you now that you are going to number 8 time. 16 -digit display. $99.00` 12 -HOUR LONG -PLAY RECORDER. Modified hate it. Panasonic. Records 6 hrs. on each side of 120 tape (supplied). Compatible with VOX and Tel assembly of electronics Rec Adapter. $119.00* Developed to make automated VOX VOICE-ACTIVATED SWITCH. Makes re- devices and products easier, quicker, and more reliable, corder self- activating with voices or other sounds. $28.50** is a manufacturer's dream - surface -mount technology TELE RECORDING ADAPTER. Records come -true, but can be a hobbyist's nightmare. PC- incoming and outgoing calls. $28.50* holes, tiny rice -grain -sized components, TELEPHONE SCRAMBLERS. Over 4,000 boards without separate codes. $199.00' just some of and ultra- compact component spacing are VOICE CHANGER. Changes man's voice to the "features" of SMT. Add to that the fact that many sur- lady's and vice versa. $49.00'" For Shipping & Handling add .$5.00 and "$2.00 per item. are available only on reels or in Colo. residents add sales tax. Mail Order, VISA, M /C, COD's face -mount components o.k. Inquire for dealer prices. Free catalog. it's almost strips, and not in quantities of one or two, and MUCH. MUCH MORE - OUR 25TH YEAR! enough to drive one to take up knitting instead. TOLL FREE 1- 800 -926 -2488 A.M.C. SALES, INC. 193 Vaquero Dr., Boulder, CO 80303 But don't despair! Things are not as bad as they look at Tel: (303) 499 -5405, Fax: (303) 494 -4924 Mon. -Fri. 8 a.m. -5 p.m. Mtn. Time first glance. Surface -mount circuitry can be assembled CIRCLE 151 ON FREE INFORMATION CARD using pretty much the same tools and materials you presently use, although you will have to learn some new techniques. What's more, as SMT gains in popularity, ATTENTION! more and more distributors are adding items to their product lines, and at prices that are affordable to the ma- ELECTR0hiIÀis jority of hobbyists. i As with every change in technology, there are going to 1 be hobbyists who will rage against surface mount. Un- Coma EARN YOUR \ fortunately, if industry dictates the change, hobbyists will ) either have to adapt, or eventually become extinct. Per- B.S.E.E. way of the dinosaurs. sonally, I don't intend to go the DEGREE know to STUDY If you agree, and want to learn what you need to THROUGH HOME Place- a successful surface -mount hobbyist, check out Our New and Highly Effective Advanced- become ment Program for experienced Electronic Tech- to Surface -Mount Technology." nicians grants credit for previous Schooling and "A Hobbyist's Guide re- to make Professional Experience, and can greatly That article gives you the information you need duce the time required to complete Program and on the differ- reach graduation. No residence schooling re- the transition, including some background quired for qualified Electronic Technicians. components available; the tech- Through this Special Program you can pull all of ent surface -mount the loose ends of your electronics background niques, tools, and materials you need to do surface - together and earn your B.S.E.E. Degree. Up- grade your status and pay to the Engineering surf ace- in 12 mount assembly; and a list of sources that sell Level. Advance Rapidly! Many finish prices that are months or less. Students and graduates in all 50 mount components in quantities and States and throughout the World. Established hobbyists. The story begins on page 45. Over 40 Years! Write for free Descriptive Lit- reasonable for erature. COOK'S INSTITUTE OF ELECTRONICS ENGINEERING Carl Laron E 4251 CYPRESS DRIVE CI E JACKSON. MISSISSIPPI 39212 3 Editor

CIRCLE 14 ON FREE INFORMATION CARD

www.americanradiohistory.comAmericanRadioHistory.Com AC OR DC OMISSIONS Congratulations to James P. Rybak on his account of the war of the currents, "AC or DC" LETTERS (Popular Electronics, Sep- tember 1994). However, his omission of Nikola Tesla's part that "Tesla had contributed in the history of AC develop- Counter," by Terry Weeder. conditioning system is almost more to electrical science than ment remains a mystery. Prior There is, I believe, an error in certainly low on refrigerant. to Tesla, any man up to his time." Pretty the schematic AC transmission lines on page 34. It I made a simple portable strong test- carried single -phase talk when considering appears that the junction currents of R2, er using a similar principle. I the long list of giants in this field and were limited to lighting. D1, and D2 should be used a six -foot length of 22- of engineering. However, other There was no self- starting in- grounded. The description of gauge stranded zip cord leaders duction motor for in electrical engineering the input circuit, in the para- power. Tesla's (speaker wire). I attached a pair made similar public statements. polyphase patents changed all graph headed "About the of small, insulated alligator clips B.A. Behrend, who did so much that. The Westinghouse Com- Circuit," also implies that the to one end and a 12 -volt incan- work with AC and induction pany gained the edge when it point would be grounded. descent lamp to the other. motors, stated that without purchased the Tesla patents. I found all of the construction (Using an incandescent lamp "Tesla's work, the wheels of Also omitted in Rybak's ac- articles interesting, as I like to instead of an LED makes polar- industry would cease to turn ... count was General Electric's build test equipment and add - ity unimportant.) The clips can our towns would be dark, our attempt to circumvent the West- ons to test equipment. be attached to the compressor mills would be dead and idle." inghouse polyphase patents. It B.S., CET lead under the hood, and the H.G. was only through cross -patent Hillsboro, MO wire routed out of the hood and Queensbury, NY agreements that GE was able to in the front edge of the door to get in on the breakthrough in place the lamp inside the MONITORING car. AC developments. 50 -MHz FREQUENCY AUTO On many General Motors AIR- The omission of the name COUNTER CORRECTION CONDITIONERS cars, there is a two -wire plug to Tesla as well as In the August 1994 issue of the word poly- I just received the November the compressor. Under tape phase Popular Electronics, I found in a history of alternating 1994 issue of Popular Elec- next to the compressor plug is a current the article "Build An Air-Con- development is unac- tronics. It contained several diode connected to the two ditioner Monitor ceptable. Lord Kelvin, the interesting articles, including For Your Car" wires. The leads of the diode famous to be of interest. However, British physicist, stated "Build a 50 -MHz Frequency on are a convenient place to con- many cars, a much simpler de- nect the alligator clips. vice can be used to warn of low Some cars do not have the refrigerant. pressure switch; the com- On most cars, a normal re- pressor continues to run even if frigerant charge will produce a the pressure is low. In that case, pressure on the low side (the the complete circuit of the Air - line from evaporator to ac- Conditioner Monitor would be cumulator to compressor in the most useful. There are, how- article's Fig. 1) of about 35 psi, ever, a couple of simple checks for a temperature of about 38 °F that can be made. with the engine idling. At driving First, on a warm, but not speed, with the compressor run- extremely hot, day, after the car ning faster, both the pressure has been driven for several and the temperature will drop. miles with the airconditioner To prevent freeze -up of the on, stop the car, but leave the evaporator, the pressure switch engine and AC running. Raise will turn off the compressor the hood. If there is any ice when the pressure gets below visible on the accumulator or about 25 -30 psi (about 28 °F). the low- pressure lines from the Then the pressure in the low evaporator to the accumulator side will rise, and the pressure or the accumulator to the com- switch will turn back on at about pressor, the system is low on 40 psi. refrigerant. Thus a simple tester can be The second check is to feel made using only R1 and LED1, the low- pressure line where it

although I would increase R1 to enters the compressor. It will be 560 or 680 ohms. LED1 will warm if the refrigerant is low, indicate Lower prices, plus jumper wires and a when power is applied cool if there is sufficient re- to the compressor. diskette. No wonder interest is rising. At idle frigerant. If refrigerant is being (stopped at a traffic signal, for lost, the low- pressure pipe at Remember, 3M Breadboards instance), carry a lifetime warranty. the compressor the compressor will get warm

For more 1 should information, call (800) 328 -0016, ext. 103. seldom, if ever, cycle off. before enough refrigerant is lost At driving speed, the rate of to make the low- pressure pipe cycling on and off will vary, warm where it comes through depending on driving speed, the firewall. outside temperature, etc. If B.S., CET CIRCLE 164 ON FREE INFORMATION CARD LED1 cycles off at idle, the air- Hillsboro, MO

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www.americanradiohistory.comAmericanRadioHistory.Com MULTIMEDIA WATCH

By Marc Spiwak I\re got a mixed bag of ing capability and more, MAX I have now is a beauty stuff this month, ranging was added to the Ultra - of a sound card that's fully from hardware to accesso- Sound. functional, while taking up ries to software. With so Now, while I don't do very only one slot. Separate in- much to cover, let's get right much recording with my terrupts are required for to it. sound card, I do like to record and playback, but have my CD -ROM drive's the new instàll software is ULTRASOUND MAX audio output patched di- improved and the card isn't This We'll and That start with a new rectly through my sound difficult to get working. sound card from Advanced card, so that I can control Sampling rates for 16 -bit Gravis, the UltraSound MAX. the volume level of CD au- digital recording are nor- Functionally, that card is dio with my software mixer. mally limited to about 44 very similar to the older Unfortunately, the only way kilohertz, but the UltraSound Ultrasound, although many to do that with the older MAX is capable of 48 -kilo-

things that I considered a UltraSound was to buy the hertz sampling for even nuisance with the older daughterboard, which also better performance. card have been eliminated added the CD -ROM audio The card features 16 ster- from the new one. input. Without the daugh- eo digital channels that The original UltraSound terboard, those mixer allow up to 32 voices to controls simply could not play at the same time. Built- be used. While the daugh- in compression lets you fit terboard was a reasonable more audio in less disk solution, it added extra ex- space. The card also fea- pense to the setup and tures an expandable 5.6- also blocked an adjacent megabyte general midi motherboard adapter -card patch set with 192 instru- socket. That's unacceptable ments. Those patches in my book, especially remain on your hard drive when extra motherboard until requested by software, expansion slots can be so at which point they are dear in a loaded PC. loaded into the card's The new UltraSound MAX memory. That hard -disk has the daughterboard patch caching makes for a built-in, which is much bet- more professional card with ter aesthetically, and great versatility; new The Equalizer -Amplifier Pro is a 30- watt-per- channel amplifier! functionally as well. The UI- patches can be made and equalizer that fits into a 31/2-inch drive bay. traSound MAX is a full - stored on disk with the rest length card (at the time of of them. As far as on -board was a 16 -bit, wave -table this writing), - but a half memory goes, 512K RAM is synthesis, stereo sound card length multilayer board is standard, and it can be with a reasonable list price due to replace it soon. The upgraded to 1 megabyte. of $199-actually, that was half -length card is sup- The card does not di- a bargain considering the posed to be functionally rectly emulate a Sound card's excellent sonic per- identical to the full -length Blaster, and so emulation formance. By itself, the one, and should be avail- software, included with the UltraSound could play back able by the time you read board, must be run to pro- 16 -bit CD- quality audio, but this. I'm supposed to re- vide Sound Blaster support only 8 -bit recording was ceive a demo of the new in DOS Windows sound is possible unless an optional card as soon as it's avail- fully supported). That used daughterboard, which able, so I'll let you know to be more of a problem. mounted on the main about it as soon as I can. Most of the top games did board added 16 -bit record- Anyway, the UltraSound (and still do) run under DOS

www.americanradiohistory.comAmericanRadioHistory.Com only, and most did not ini- Measure It All! tially provide direct UltraSound support. Unfor- The DMM /LCR Meer/ tunately, running the emulation software often Frequency Counter. All in One. caused problems, both major and minor. Today, Troubleshoot down to the however, most good soft- component level - ariy ware packages provide component! Verify poorly direct UltraSound support, marked parts, test for toler- with which is compatible ances and damage. Wavetek's MAX or oth- any UltraSound, new DM27XT is not only a full - and more are erwise, function DMM, but also time. With adding it all the includes complete inductance, support, direct UltraSound capacitance, and frequency of the best you'll hear some measurement capabilities. digital sound you've ever heard, especially for MIDI. Wide LCR range: The card also has a few 10 12 to 2000 MO goodies that go beyond its 10pFto2000pF excellent sound support. A 100 pH to 20 H speed- compensating Autoranging frequency joystick port is built into the meter 10 Hz to 20 MHz card. That is a must for to 20 A anyone with a fast PC, sim- Ac and dc current ply because the standard Logic test, diode test, max PC game port is too slow reading hold, continuity for today's PCs. (Unfor- beeper, input warning

tunately, I understand that beeper, fused input 1.1.0 F Hh Lw+ even this speed- compen- protection, battery saver 1001) _: = 75,) " sating port has speed 20) V 20 problems with some of the Consolidate your test bench with 2 new and extremely fast one meter that does it all - 200m Pentiums.) The speed -com- Wavetek's high -performing, 200n pensating port is also full -function XT Series DMM. 20n 20A- in a separate It's all in one compact, rugged, available 2n- game -controller card from field -ready package with a big 204t Advanced Gravis, but hav- 0.7 -inch, 31/2 -digit display. ing the feature built into the Insulated probes and alligator sound card saves an ex- clip leads are included, and pansion slot. there is a huge selection of The UltraSound MAX also accessories, including current, has three built -in CD -ROM rf and HV probes, temperature holsters, and cases. interfaces for Mitsumi, Sony, converters, DM27XT and Panasonic drives; the Ask for Wavetek DMMs. They're card does not support SCSI the meters to pick when you devices. External con- have things to fix. nectors on the card include stereo line -in, line -out, a 4- watt amplified output, and a joystick/MIDI adapter. A full suite of audio -related software is included with the card, allowing you to do anything you want with sound. With its improved design, better software, list $11995 price of just $299, and Other XT Series DMMs from $89.95 more popular direct sup- the UltraSound MAX is port, U.S.A.: (619)279 -2200 K that I highly WAVe.Te a sound card Europe: (44/243) 531323 recommend. Asia Pacific: (852)865 -1903 01993 Waverek Corporation

CIRCLE 168 ON FREE INFORMATION CARD

www.americanradiohistory.comAmericanRadioHistory.Com AN ACCESSORY kets a full line of Platinum multiple CD -ROM drives to SOURCE Sound Audio Cables that a single sound card. Con- Accessories are often save you the trouble of tact SC &T2 for prices. used to solve problems or making your own. Cables Another multimedia add new features to some- are also available that al- problem is where to put ali thing you already have, low the connection of the CD- ROM's. SC &T2's CD3 and multimedia is an area Compact Disc Storage Sys- where accessories are sure- tem holds up to 40 discs ly welcome. Where To Get It A company (but not their jewel -box called SC &T2 markets lots of Advanced cases) on edge in a hori- multimedia accessories that Gravis 1790 Midway Ln. zontal cylinder- shaped address some common Bellingham, WA 98226 case. The case folds open problems. Up to 30 discs automatically Tel. 800 -663 -8558 at the middle with the discs pop out of Elecom's CDR -001 Often, when a multi- AmSoft resting in the at the touch of a finger. bottom half. media PC is set up from PO. Box 666 Discs fit in numbered slots scratch, there is no New Cumberland, PA 17070 conve- and disc labels fit in num- nient way to Tel. 717- 938 -8249 adjust volume much power. On the other bered spaces behind a levels on amplified speak- hand, many people might Blue Mountain Software, Inc. clear plastic window. A P.O. Box 1648 ers without getting up and want to use speakers that cover slides Port Angeles, over the win- turning the volume control aren't self -amplified, or are WA 98362 Tel. 206 dow. To retrieve a disc, you on -452 -1251 one or both speakers, or unhappy with the amplify- simply slide a selector knob Broderbund exiting your software and ing power or sound quality Software to the 500 Redwood Blvd. desired disc number, adjusting a volume level of a pair of amplified Novato, CA 94948 open the case, and the from a software control speakers. If that last state- Tel. 800 -521 -6263 requested disc is "stuck" to panel. Sometimes a volume ment describes you, check Davidson & Associates, Inc. the lid, ready for you to control is located on the out SC &T2's Platinum Sound 19840 Pioneer Ave. grab. The case can also be back of the sound card -a Equalizer- Amplifier Pro. That Torrance, CA 90503 "locked" and carried location Tel, - 793 that's usually diffi- unit packs 60 watts of 310 -0600 around by a folding handle cult to reach. power (30 per channel) Elecom Computer Products, that's built-in. The disc hold- SC &T2's Platinum Sound and an equalizer into a Inc. er has a list price of about 17316 Edwards Road, Multimedia Volume Control- standard 31/2 -inch comput- $35. Suite B -225 ler is a handy little gadget er drive bay. The device will Cerritos, CA 90703 Coincidentally, I also re- that solves those problems in also fit a 51/4 -inch bay Tel. 310-802 -0077 ceived a new CD -ROM and more, and has a list with an adapter. holder from another Grolier Electronic Publishing, com- price of only $24.95. That The front panel of the unit Inc. pany called Elecom. The simple device, about half contains a volume control, Sherman Turnpike CDR-001 holds up to 30 the size of a mouse, mounts a balance control, a 7- Danbury, CT 06816 discs in their jewel boxes. on the side Tel. 203- 797 -3500 of a monitor band slide -control equal- What's neat is that the discs with double -sided tape and izer, and stereo LED volume - LucasArts Entertainment slide into slots with springs in has volume Company a control knob level indicators. It is easily the back. To retrieve a disc, P.O. Box 10307 on its face. A four -foot ca- connected to a sound card you simply lift the front San Rafael, CA 94912 of ble connected to the or CD -ROM drive a - at back Tel. 415 -721 -3300 the disc over a small lip controller splits into a "Y" at panel plate or inside your and it pops right out of the Microsoft Corporation the end where a stereo computer. The Equalizer - One Microsoft Way holder and into your hand. input plug and stereo out- Amplifier Pro runs off 12 volts Redmond, WA 98052 -6399 As your CD -ROM collection put jack are located. The DC, which it gets from your Tel. 206-882-8080 grows, multiple CDR -001 plug plugs into the output PC's (or Mac's) power sup- Multicom Publishing holders can be ganged to- on your sound card and ply. While many people 1716 Locust Street gether side -by -side or your speakers plug into the would have no need to Des Moines, IA 50309 vertically. The CDR -001 re- jack. After initially setting spend $119.95 on this de- Tel. 800-850-7272 tails for $24.95. the volume level on your vice, many others could Pro CD, Inc. sound card and speakers, find it to be a valuable 8 Doaks Lane, Little Harbor NEW STUFF the Marblehead, MA 01945 Multimedia Volume addition to their multimedia Being that this is Tel. 508-750-0000 the first Controller makes it easy to set -up. An external version is Popular Electronics issue readjust the volume. also available for $149.95. SC &T2 International, Inc. of 1995, I guess I'm a month Amplified speakers are Another problem that 3837 Lasalle Street Phoenix, AZ 85040 too late with news of two quite popular in the multi- comes up when mixing and Tel. 602- 470 -1334 discs sent to me from media market because matching multimedia com- Grolier Electronic Publishing: WexTech Systems, Inc. many sound cards have no ponents is finding the right 310 Madison Ave., Suite 905 The New Grolier Multimedia -in built amplification, and cable that will connect au- New York, NY 10017 Encyclopedia, and the 1994 many cards with built -in dio from a CD -ROM drive to Tel. 212 -949 -9595 Guinness Multimedia Disc of amplification don't pack a sound card. SC &T2 mar- (Continued on page 92)

www.americanradiohistory.comAmericanRadioHistory.Com CI; A CHRONICLE OF CONSUMER ELECTRONICS (

Apple's Newton

NEWTON MESSAGEPAD 110. Manufac- tured by: Apple Computer, Inc., 20525 Mariani Avenue, Cupertino, CA 95014. Price: $599.

Almost one year ago, in a special issue of Gizmo, we reviewed the first crop of personal digital assistants or PDA's. We were less than enthusiastic about the Sharp Newton Expert Pad, the Tandy /Casio Zoo - mer, and the AT &T Eo Personal Commu- nicator. Although we appreciated the technology and vision that was evident in each one, we were ultimately disappointed with how all of the products worked. What a difference a year makes. The Eo is already dead -AT &T closed down its Eo subsidiary in the second half of 1994. The Zoomer platform will apparently be orphaned -no product upgrades are in the works. On the other hand, Apple Comput- er has significantly improved its Newton MessagePad and has greatly expanded its by a factor of three, to one mega- hardware in an Apple upgrade program, in which creased Newton Product family of both offers one the Newton MessagePad will get the same byte. The MessagePad also and software. can be as the new Newton. The PCMCIA type -2 card slot. which The weaknesses of the original Newton internal software and comes with two used for additional storage or for dedicated PDA were its limited memory, short bat- upgrade costs $99, The user can application cards. tery life, awkward input, and several bugs Newton software products: Newton Connection Kit, Dell The new MessagePad is significantly as well. All of the product's deficiencies choose from DrawPad, and Dyno better with respect to battery life. Estimat- seemed even worse in the face of the huge Crossword Puzzles, ed life is as much as 20 hours in active use John Scully -who NotePad. amount of hype from are used. Re- The MessagePad 110 looks slightly dif- when alkaline batteries has since departed Apple-that preceded pro- It's a little slim- chargeable nickel -cadmium cells will the release of Newton by a couple of years. ferent than its predecessor. x 11/4 inches. It vide about 12 hours. of the product's ability were mer, measuring S x 4 Expectations Another huge improvement made in the way the real weighs just over 11/4 pounds. The best im- so high that there was no for de- its housing is the cover, MessagePad is that it now allows device could live up to them. provement in from the screen and ferred recognition-users can take notes The original Newton also suffered from which flips up away very in electronic ink, and then go back and its high price and its inability to do very folds over the back -something turn them into text. The one problem with were available for much like the Zoomer. much. Few applications recognition is that the user was poor. The MessagePad is still available with deferred it and its communications ability feedback, and its original form factor as the MessagePad doesn't get immediate Before the MessagePad was introduced, way to $100 less than the Mes- therefore doesn't learn the proper the press was full of complaints from pun- 100. It sells for write. The big advantage is that you can was taking too sagePad 110. dits who felt that Apple without worrying whether it The three most important improvements write quickly, long to get the product to market. After are the MessagePad are Newton will make sense of what you was introduced, the general consensus was that were made to improved battery life, writing. that the product was released too soon. increased memory, recognition. The basic built -in software that comes Users who were unfortunate enough to and deferred handwriting -in RAM was in- with the MessagePad includes the Note- 9 purchase the original Newton can take part The size of the built

www.americanradiohistory.comAmericanRadioHistory.Com pad. the Name File. and the Date Book. choices. If none matches, you can tap a fact, much of the software that is available All entry to the device is made by writing keyboard icon to bring up a "keyboard" for the MessagePad comes on floppy disk or tapping on the LCD screen with a styl- on which you can tap the word. and is installed through the Connection us. In the new MessagePad. the stylus is a A big improvement in the new Mes- Kit. The Connection Kit is also valuable round, telescoping plastic- tipped "pen" sagePad is that if it gets a word wrong, and for backing up information, which it does that stores away in a hole in the side of the if the word that you want doesn't appear on automatically on each connection. unit. It's a big improvement over the one the word list, you can tell Newton to reex- The Connection Kit allows the Mes- supplied with the original Newton. The amine the word using letter-by- letter rec- sagePad to be used more efficiently. It al- stylus isn't absolutely essential, however. ognition. The original MessagePad did lows programs to be loaded and unloaded An ordinary pencil works well in a pinch have character-based recognition, but not from memory so that the user can make the as does a plastic capped pen-or almost like this. Here you can switch back and most out of what he or she has. It also anything else that won't scratch the glass. forth between word- and character-based allows data to be entered in a much less We often found ourselves even using our recognition with a single pen tap. We cumbersome way. index finger -although more often to found that it could often do a great job at it. The Newton Print Pack is another essen- point to an item to select it than to actually The feature removes a lot of the frustration tial accessory. It allows the MessagePad to write. that was inherent in the original product. print to any printer that can emulate an HP The Notepad is for keeping free -form The MessagePad also features a shape LaserJet, Canon Bubble Jet, or Epson notes and memos. It is always running recognizer. When that feature is turned on, printer. The print pack consists of a when the machine is on, although it is sloppy sketches are cleaned up so that cir- "smart" serial -to- parallel converter that sometimes covered by other applications. cles are round, rectangles have square cor- has printer drivers built -in. The notes can consist of letters, numbers, ners, and so on. Another accessory that we tried was the and even drawings. The writing can be With the original MessagePad, we com- Newton Fax modem model H0005. The converted into text by the recognizer, or it plained that we really couldn't do anything shirt- pocket sized modem is powered by can be left as "electronic ink." Unlike the with it except keep notes and some names two AA batteries and connects to the Mes- first Newton, the ink does not have to be and addresses. Apple promised far greater sagePad's serial port. It adds greatly to the converted to text immediately. Instead, it functionality than it delivered in that unit. functionality of the MessagePad. can be converted at a later time. That's an That wasn't the case this time. The hard- Of course, all the hardware in the world important advantage, because you don't ware and software accessories that were is of little use if it is not accompanied by have to worry about writing too fast and only a promise the first time we reviewed good software. Unlike our first experience having to wait for the recognizer to "catch Newton are available in abundance now. with the MessagePad, software is now up" to you. One convenient accessory is a charging available. Descriptions of some of the soft- Like the original MessagePad, the 110 station that can recharge the internal bat- ware we examined follows. has a menu where you can set your prefer- teries in two or three hours. The charging ences and customize the recognition en- station can also hold an extra set of bat- SOLITAIRE AND OTHER CARD gine. The recognizer, for example, can be teries. Both sets can be recharged at the GAMES. From StarCore, Apple Comput- set to recognize words, letters, or num- same time -it takes about four to six er, Inc., 5 Infinite Loop, Cupertino, CA bers. As in the original MessagePad, the hours. In the original MessagePad, the 95014. Price: $39.95 Newton is most efficient when it looks at recharging took almost 14 hours! entire words and matches them with words The charging station fits comfortably on The Solitaire package is supplied on a in its dictionary. After practice -the Mes- a desktop, and even holds a full -sized styl- floppy disk, so the Newton Connection Kit sagePad includes a practice mode be- -we us. The MessagePad can be used while it is is required. It offers players four different came reasonably proficient at writing the recharging. card games: traditional solitaire, black- way that the Newton wanted us to. Perhaps the most important accessory jack. baccarat, and video poker. In all the The MessagePad does a pretty good job for the MessagePad is the Newton Con- games, money is on the line. of recognizing words in its dictionary if nection Kit. The kit consists of software you write properly. However, if a word that runs under Microsoft Windows, a isn't in the dictionary, the resulting trans- manual, and a cable that lets you connect lations can be bizarre. That problem led to the Newton to your PC's serial port. (A almost universal criticism of the original Macintosh version is also available.) That Newton. Fortunately, it is possible to add not only lets you backup and save data, but words to the Newton dictionary, so that lets you transfer data from your computer words that you use frequently will be rec- to the Newton. ognized. Say, for example, that you want to use Word recognition is not always desir- your MessagePad to keep a record of busi- able. For example, entering names in the ness contacts -contacts that you already Name File can be particularly cumber- had on a database on your PC. With the some. Naturally, the Newton dictionary is Connection Kit, you could download the not filled with surnames, so virtually every names and other information into the New- name that is entered will have to be cor- ton Name File. As long as the database can rected. Correcting a word consists of tap- export in a standard delimited file (SDF) ping on it to bring up a list of possible format, you can use the information. If you add names and other information while you Gizmo is published by Gernsback Publica- use the Newton portably, you tions, Inc., 500 -B Bi- County Blvd., Farm- can update your computer's database by Built-in help explains how the games ingdale, exporting NY 11735. Senior Writers: Chris F. the information from the New- are played, which we found helpful to O'Brian and Teri Scaduto. Copyright 1994 ton. learn the rules of Baccarat. Unfortunately, by Gernsback Publications, Inc. Gizmo is a The Newton Connection Kit is so im- the package is somewhat addicting -we registered trademark. All rights reserved. portant that it is virtually indispensable. In spent far too much time playing when we

www.americanradiohistory.comAmericanRadioHistory.Com time is FINGERTIP FOR STATS- BASEBALL. should have been working. In any case, out of words before their allotted length, From Fingertip Technologies, Inc., 140 we're glad that we weren't playing with up. Both the overall presentation Dr., Suite 200, New- and the time for each slide can be tracked. Newport Center real money! Price: $129. Oversized buttons allow the user to port Beach, CA 92660. through the PRESENTERPAD. From Avalon Engineer- move forward or backward set for ei- If you are serious about sports, you'll ing, Inc., 45 Newbury Street, Boston, presentation -and they can be love Fingertip for STATS, a sports- infor- MA 02116. Price: $89. ther right- or left -handed operation. delivers statistical analy- In the Slide Manager, key points for mation tool that once, or they sis of every Learn in the majors. STATS- PresenterPad bills itself as "the world's each slide can be displayed at is Sports Team and Analysis Tracking Sys- first truly portable teleprompter." The aim can be expanded as each bullet item tems, Inc. -has been a staple for baseball of this disk -based product is to help any- discussed. It even allows presentation with Newton's reporters for years. The software helps to one who ever speaks to a group of people equipment to be controlled However, an bring the same information to Newton to give better presentations. It has three built -in infrared transmitter. for that feature users. basic functions: The Slide Manager, which infrared receiver is required be available later is designed to help deliver presentations to work. It is expected to that are accompanied by slides or overhead this year. transparencies; the Teleprompter, which LIST MAN- scrolls text either manually or at a preset NOTION: THE NEWTON Inc.,15 SW Colora- speed; and the Outliner, which helps to AGER. From Eidetic, Price: $59. prepare and edit the information that is do Ave., Bend, OR 97702. displayed in the Slide Manager and Tele- to keep track prompter. Notion allows the Newton of virtually anything from agendas and trip plans to ATM withdrawals. The list templates provided with Notion include up to fifteen different data fields for dates, flights, hotels, names, numbers, or other data. Over 100 templates are provided with Notion. They can be used directly, or they can be modified to create new ones. Searches for information through key- words can be made through multiple lists, so you can't "lose" information that you With access to the STATS online service, you never have to worry about not having up-to -date information. Access costs 50.25 per minute; an average update requires about 4 minutes. Included in the price of purchase is two hours of online time. The software, with its mass of statistics, requires atwo- megabyte storage card Gas -gauge -style indicators provide to install. That can be reduced somewhat easy-to -see time information. That is par- by deleting, for example. the layouts of the ticularly helpful for speakers who are con- 28 Major League stadiums. stantly running out of time before the key The software's main menu offers five points have been presented -or running

[lavsN 12:51 12:54 00:33 Four score and seven years ago our fathers brought forth enter, even if you forget what list you put it in. For example, there's no need to worry if on this you put information about your airline continent, a tickets in your "things to buy" list instead nation, of your "vacation planning" list. In a way, new Notion becomes a value -added replace- [conceived in ment for the MessagePad's built -in liberty, and Names, Dates, and Notepad applications. to If you are someone who has to keep dedicated track of projects, expenses, or other the proposition data -or if you're just someone who loves that all men to make lists- Notion is a package that will make the Newton MessagePad invalu- L:t,,1 ® able. 11

www.americanradiohistory.comAmericanRadioHistory.Com options. First is Play Ball, which provides MOTILE. From StarCore, Apple Com- the tools to review in -depth statistics and puter, Inc., 5 Infinite Loop, Cupertino, to track player performance while scoring CA 95014. Price: $59.95. a game. Second is Major League Update, Sr which provides up -to- the -minute news 12 46 :r'3-.br+-4 Motile is a PCMCIA card that turns the stories, league standings, and analysis MessagePad into a challenging puzzle of from around the league. eeK.+yr4ant zc? lops Losp

FODOR'S 94 TRAVEL MANAGER: TOP U.S. CITIES. StarCore, Apple Computer, Inc., 5 Infinite Loop, Cupertino, CA 95014. Price: $119.95.

The Fodor's PCMCIA card has all the information that travelers would find in eight separate hardcopies of Fodor's city guides. Within each city, users can view PocketCall comes in two parts: Pocket - their location and actually receive driving Call itself, and Services, which is used to directions from one place to the next. Res- configure PocketCall to connect to dif- taurant information, including menus, is ferent information providers. It stores such also available. You can find a restaurant information as phone access numbers and based on variety modem-setup information. a of categories, from cui- Users who sine to location, to price. don't want to enter the setup themselves Included with FilePad is FilePad Link The eight cities that are covered in can purchase optional PocketPacks - the which computer- connection software that allows guide are: Atlanta, Boston, Chicago, come pre- configured for specific remote records to be transferred between the New- Dallas, Los Angeles, New York, San Fran- services. ton and the PC. Formats that are supported cisco, and Washington, D.C. Up to 250 PocketCall allows users to store scripts include Lotus 123, Quattro, Symphony, entries are provided for each city, includ- of frequently used comments that you can Excel, and DBase. Data can also be output ing the locations of fast -food joints and send at the touch of the screen. So for in ASCII as either tab -delimited, comma automatic teller machines. example, a user who regularly visits the separated, or quoted strings. Once the desired city is selected, the Newton Forum on CompuServe could Any information that is stored in File - main menu offers such choices as: Mar store "Go Newton" and visit the forum by Pad can be printed, Faxed, or sent as E- Introduction, Airport, Dining, Lodr ing, tapping on the script instead of having to mail. Free Time, Services, and Directions. U

www.americanradiohistory.comAmericanRadioHistory.Com Groat Gift Ideas

TECHNOLOGY UPDATE

500 miles from nowhere, e it'll give you a cold drink i or a warm burger...

NASA space flights inspired this portable fridge that outperforms conventional fridges, replaces the ice chest and alternates as a food warmer.

By Charles Anton

ecognize the ice cooler in this picture? spoiled food. No more! Now Surprisingly enough, there isn't one. for the price of a good cool- What you see instead is a Koolatron, er and one or two seasons R ice, (or about five an invention that replaces the traditional ice of buying all the cooler, and its many limitations, with a tech- family restaurant meals), than your advantages of home cooling are available for nology even more sophisticated Limited time suited to travel. you electronically and conveniently. home fridge. And far better offer. Because Comtrad is bringing this offer innocent looking box be- about your last trip. You just got What's more, the Think to directly, you save the cost of middle- a vacation. you fore you is not only a refrigerator, it's also away nicely on your long -awaited mark-ups. For a limited time You're cruising com- men and retail food warmer. get this advanced, portable in your car only, you can por- fortably NASA inspired refrigerator from outer space. busy interstate Koolatron refrigera- refrigerator. The along a table with only a few rest tor at the introduc- trav- secret of the Koolatron Cooler/Warmer Because of space The stops or restaurants. tory price of $99. that to take el's tough demands, is a miniature thermo -electric module You guessed it... the Call today had to find of this scientists effectively replaces bulky piping coils, loud kids want to stop for a advantage more de- promotional something used in conven- snack. But your Kool- special less motors and compressors orders pendable and atron is stocked with pricing. Most tional refrigeration units. In the cool with- bulky than traditional fruit, sandwiches, cold are processed reduces the outside refrigeration coils and mode, the Koolatron drinks, fried chicken... in 72 hours. compressors. Their re- temperature by 40 degrees F. At the fresh and cold. Every- Try It risk free. search led them to dis- switch of a plug, it becomes a food warmer, body helps themselves We guarantee your cover a miraculous going up to 125 degrees. and you have saved satisfaction with solid state component valuable vacation time any product from called the thermo-elec- and another expensive Comtrad Industries. The versatile Koolatron is avail- Tight The P24A holds tric module. sealing restaurant bill. With the Koolatron able in two sizes. lid Aside from a small you get our com- 30 quarts and the snwller P9 holds Hot or cold. With the seven quarts. An optional AC fan, this electronic Large "No Questions switch of a plug, the plete adaptor lets you use them in your fridge has no moving capacity day Koolatron becomes a Asked" 30 rec room, patio or motel room. to wear out or to parts Easy for a money -back guar- They plug into any regular outlet. Urethane food warmer break down. It's not side insulation antee. Plus you get bendier casserole, burger or affected by tilting, jar- limited warran- baby's bottle. It can go a full one year manufacturer's ring or vibration (situ- ty. If you are not satisfied for any reason, just Tight up to 125 degrees. ations that cause home sealing return the product for a complete refund. latches to toot there fridges to fail). The cord with And because Koolatron (P24A) holds 30 quarts $99 $16 S&H High are no temperamental governing module, no fighter $8 S&H pact adapter Koolatron (P9) holds 7 quarts $79 bigger than a match- plastic compressors or gasses, Optional AC Adapter (AC 1C) $49 $6 S&H book, actually delivers the Koolatron works PL1106. the cooling power of a perfectly under all Please mention promotional code 025- 10 pound block of ice. circumstances, even For fastest service call toll -free 24 hours a day weighs From satellites to station wagons. upside down. Empty, the large model 12 pounds and the smaller one weighs 800-992-2966 Thermo -electric temperature control has now only Ow-° just seven. Full, the large model holds up to ._ been proven with more than 25 years of use in i, and the smaller one holds six. ® some of the most rigorous space and labora- 40 12-oz. cans To order by mail send check or money order for the tory applications. And Koolatron is the first Just load it up and plug it in. On motor total amount including S&lf (VA residents add 4.5% manufacturer to make this technology avail- trips, plug your Koolatron into your cigarette sales tax). Or charge it to your credit card by en- and expiration date. able to families, fishermen, boaters, campers lighter; it will use less power than a tail light. closing your account number and hunters - in fact anyone on the move. If you decide to carry it to a picnic place or a long way Koolatron will hold its cool- COMIRAD Home refrigeration has come a fishing hole, the INDUSTRIES since the days of the ice box and the block of ing capacity for 24 hours. If you leave it 106 ice. But when we travel, we go back to the plugged into your battery with the engine off, 2820 Waterford Lake Drive Suite Midlothian, Virginia 23113 sloppy ice cooler with its soggy and sometimes it consumes only three amps of power.

www.americanradiohistory.comAmericanRadioHistory.Com Aurora Bosealis

OLDSMOBILE 1995 AURORA WITH BOSE AUDIO SYSTEM. From Oldsmobile, 920 Townsend, Lansing, MI 48921 and Bose Corporation, The Mountain, Framingham, MA 01701. Price: $32,000.

Only a couple of years ago, General Motors reportedly was thinking of closing Oldsmobile division because of lackluster performance. However, if our recent test drive of a 1995 Aurora is any indication, Oldsmobile is back with a vengeance. The Aurora is a four-door luxury auto- mobile that is targeted to appeal to baby boomers who might otherwise consider the Infinity J30 or Acura Legend. It's powered by a 4 -liter V -8, and is as far removed from its immediate predecessors always has a comfortable feel of control. tion allows him to design a complete sys- as a Pentium -powered PC is from an XT. Best of all, the adjustment is continuously tem that, in theory, should out -perform a Perhaps to distance the Aurora from variable, so it is transparent to the driver; system assembled from stock compo- Oldsmobile's recent past, the car does not we were never consciously aware that the nents. have an Oldsmobile badge anywhere on its assist level was changing, even though it The Bose audio system installed in the outside. The only Oldsmobile nameplate was obvious that it did. Aurora consists of an AM /FM /cassette is inside, on the radio's trim. In general, the Aurora is fantastic. It head unit, a 12 -disc trunk- mounted CD A host of electronic goodies is supplied provides a quiet, comfortable ride while changer, six speakers, and an Acoustimass as standard equipment in the Aurora, in- still providing a good feel for the road, and enclosure. cluding traction control, antilock brakes, V -8 performance that we normally Bose's Acoustimass speaker tech- and cruise control. Also included is an wouldn't associate with Oldsmobile. On nology is the same that is used in several of automatic day /night rearview mirror that the twisting roads of upstate New York, the the company's home products, including helps to reduce annoying glare during car's performance made it a thrill to drive. its AM -5 and AM -3 speaker systems. The nighttime driving. A 4- speed, elec- On the other hand, its luxurious surround- Acoustimass enclosure launches sound in tronically controlled transaxle offers se- ings made the slow, rush -hour traffic of the form of a mass of air, rather than di- lectable (normal or power) shift points. A New York City bearable and maybe even rectly from a vibrating surface like a trip computer, which Oldsmobile calls a enjoyable. speaker cone. A speaker cone is still used, driver information center, allows the driver To be honest, however, we must plead of course -in this case a 61/2-inch to track his or her fuel economy, speed, ignorance when it comes to luxury cars - woofer-but it is the air that is sent forth engine oil pressure and life, battery life, our real -world experience with them is, from the enclosure's port, after passing transaxle fluid life, distance to destination, shall we say, limited. So we turned our through resonant cavities, that does the estimated time of arrival, and more. Re- attention to one of the three pieces of op- work. mote- controlled door and trunk locks are tional equipment that we do know some- The Acoustimass enclosure acts as an also standard. thing about. No it's not the V -rated acoustic bandpass filter, and it also helps to As a luxury car, the Aurora also offers Michelin tires or the engine block heater. limit the speaker cone's excursion, thus such creature comforts as upper and lower It's the Bose Acoustimass audio system reducing distortion. lumbar supports for both the driver and the that we spent most of our time examining. The Acoustimass enclosure delivers front -seat passenger, and dual temperature Oldsmobile selected Bose in an attempt bass response that is surprisingly clean, control so that both the driver and pas- to persuade Aurora customers to buy a smooth, and powerful despite the mod- senger can be comfortable. The driver's factory- installed sound system instead of ule's relatively modest size. In fact, the seat offers two position memories so that if an aftermarket system. The auto -sound af- module is quite inconspicuous -it is inte- two people regularly share the car, each termarket is an extremely strong industry. grated in to the rear package shelf. Even can store a preferred seat position. Even A survey conducted by the Electronic In- when you open the trunk you won't notice more important, the outside rear-view mir- dustries Association found that more than it unless you look for it. ror positions are also stored with the seat 70 percent of all U.S. households own at location in the memories. As an added least one piece of aftermarket car-stereo convenience, pressing both memory but- equipment. Twenty-three percent of those tons simultaneously causes the seat to surveyed intended to buy an aftermarket move completely down and back for easier autosound product in the next 12 months. exiting. However, a factory system can provide a The Aurora's power steering offers what distinct advantage over aftermarket in- Oldsmobile calls magnetic speed-variable stallation. Specifically, the sound system assist. That feature keys the strength of the can be custom tailored to the vehicle. The power-steering assist to road speed -max- system designer knows what the interior is imum assist is provided during parking like, where the speakers will be mounted, The Bose Acoustimass system consists maneuvers, and minimum assist is pro- where the passengers will sit, and even of six speakers plus the Acoustimass vided at highway speeds so that the driver how big the trunk is. Using that informa- enclosure.

www.americanradiohistory.comAmericanRadioHistory.Com GIZMO NEWS

Balance of Trade much confidence in the theft- deterrence The Powered Acoustimass enclosure is (Eclipse Secur- The Electronic Industries Association provided with its new ESN an integral part of the Aurora's package /FM /CD play- reports that U.S. exports of electronic ity Network) -equipped AM shelf. to provide products reached more than $48 billion in ers that the company guarantees enclosure unit if it is stolen Mounted to the Acoustimass the first half of 1994. That represents a free replacement of the which con- is the power- amplifier module, growth rate of about 16% over the previous up to a year after purchase. for the Acoustimass tains one amplifier year. However, U.S. imports of electronics enclosure and four other amplifiers for the The resulting ,. were up even more: 18%. -.. am a main speakers. Each amplifier includes in negative balance of trade for electronics . . networks _ ,.,.,,..,... active and dynamic equalization the first half of 1994 was $7.9 billion. IN accurate E ... that work together to provide When he announced the trade statistics, at any listening sound and tonal balance EIA President Peter E. McCloskey said, levels, level. For example, at low volume "U.S. exports are continuing to exhibit the vehicle, the deep bass is automatically boosted. substantial vitality and improvement in The units, when stolen from en- according to The beauty of the Acoustimass global market share. This is particularly become inoperative. Thus, visibly in- units sim- closure is not that it is true of outstanding performing sectors the company, "ESN- equipped the mod - fence value." Unlike conspicuous. More important, such as telecommunications and solid - ply will not have any bass output systems, users ule -despite its impressive - state products." similar theft -deterrence Whether secret codes. is acoustically inconspicuous. The category where the U.S. had the don't have to remember any or back to remember their we were in the front seat -even largest positive balance of trade, $2.5 bil- Instead, they just have of the unit is origi- with our head directly in front lion, was in industrial electronics. The "Key CD." When the Eclipse localized on selects a CD Acoustimass port-we never worst performance, as might be expected, nally installed, the customer on The CD player is then the bass. We could carry conversations was in consumer electronics, where the from his collection. comfor- that CD as the with front- or rear-seat passengers U.S. had a $6.4 billion negative balance. programmed to recognize music. No tably even while enjoying the Other negative categories include comput- key. beaten over reactivate the sys- one felt as if they were being ers and peripherals and passive compo- After ten attempts to system. the unit's display the head by an aggressive stereo nents. tem using incorrect CDs, for free Six other speakers round out the Bose Meanwhile, the U.S. Semiconductor prompts the user to contact Eclipse a 61/2-inch the unit is deliv- system. Each front door holds Industry Association reported that success repair and shipping. Once panel can Bose woofer, and each front kick "can be achieved by sustained efforts to ered for the "free repair,'" technicians In each rear number to identify houses a 11/2-inch tweeter. improve foreign access to Japan's semi- read an electronic serial speak- door is a 31/2-inch Bose "Twiddler" conductor market." The association re- the unit's registered owner. create a er. The speakers are mounted to ported that the foreign share of Japan's -fire pattern that provides what Bose cross semiconductor market exceeded 20% for Info Highway? calls a "Stereo Everywhere" effect. the first three quarters of 1994. A survey conducted by the Times Mir- Bose certainly was effective with "Ster- Speaking of the 1991 U.S. -Japan Semi- ror Center for The People and The Press eo Everywhere." Sounds seemed to ema- associa- conductor Trade Agreement, the found that 11- million U.S. homes are "al- nate from every corner of the car! is a tion said, "The foreign share increase ready equipped to travel the information that's not how we like our Unfortunately, result of the sincere efforts being made by highway." Nearly one third of U.S. house- imaging isn't realistic. It was discon- -it all parties to provide competitive products holds own a personal computer, and about certing to hear trumpets blaring from what the to Japanese customers, coupled with 23- million adults use a home computer seemed like the floor behind us. Yes, the movement offshore of low-end consumer every day. Bvelve percent of all house- washed the car in sound, and we're system electronics, which have a relatively small holds have a modem -equipped computer, sure that that is what Bose's engineers foreign market share. However, no one and as many as 6% of all Americans go intended. should be satisfied until the notion of a online. displeasure with the Except for our truly open Japanese semiconductor market People who enjoy high -technology system performed very much imaging, the becomes a reality." products are "voracious consumers of in- head unit was well de- to our liking. The In July, 1994, Japan made an effort to formation," the study found. "They read easy to use. All of the controls signed and terminate the 1991 agreement. The associ- more, follow the news more, and know were obvious with one exception: The but- ation said that it hoped "that Japan's effort more about the world than people who are CD-track playback was un- ton for random ... is not an indication of a lack of commit- not as technologically experienced." Controls mounted on the steering labeled. ment to continue to improve market ac- However, people who do access informa- functions were easy to wheel for basic cess. Instead, we are once again calling tion using such high -tech methods as to, but the placement of the head our adapt upon the Japanese industry to match online services do not forsake such tradi- slightly toward the driver, unit, curved commitment to provide choice to Japanese tional information sources as newspapers undue attention. didn't require consumers, and ensuring a truly open mar- and magazines. Bose system performed Although the ket for all semiconductor competitors." The dominant home -technology de- it was not as much to our liking admirably, vice? Well, it's the TV. of course. Less auto implementations. An as other Bose than 60% of those surveyed, however, v., re aftermarket system, we think, could prob- Theft -Proof Radios mere noise- satisfied with what's on, even though only a better job whether it could Car alarms have become ably do -but 7% of all households used their TV for match the $1000 price premium of the makers instead of theft deterrents. CA) has so broadcast reception only. 15 Bose system is uncertain. However, Eclipse (Torrance,

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S -35 LOUDSPEAKERS. Manufactured by: Canon U.S.A., Inc, One Canon Plaza, Lake Success, NY 11042. Price: about $425 per pair.

There have been many technological advances in audio over the last dozen years or so. But since the introduction of the CD player, it's not electronics that is advancing the most rapidly. Instead, it's the loudspeaker -the most mechanical component of an audio system -that continues to undergo the greatest refinement. To a degree, the changes in speakers have been driven more by changes in fashion and lifestyle than because of new tech- chamber includes both the top dome and stands or wall brackets are one option; nological discoveries. But the continuing the base. direct -coupled attachment points are pro- evolution in loudspeakers has come about The objective of the speakers' unique vided on the rear panel to maintain the for another reason as well. With the intro- design is to provide a true stereo image up rigidity of the structure. They can also be duction of the compact disc and its uni- to six times larger than a conventional placed on top of a shelf or other furniture; formly good ability to accurately speaker so that more listeners, over a six anti -slip stick-on feet are supplied for reproduce audio, the loudspeaker has un- wider area, can enjoy stereo without that purpose. Although not an optimum questionably become the most important crowding into the typical small "sweet position, the speakers can even be placed link -we should say the weakest link -in spot" that is generated by conventional on the floor. the audio -reproduction chain. speakers. The Canon Wide Imaging Stec Like all speakers, the frequency re- The bookshelf speaker-first intro- eo technology is patented and it is, indeed, sponse of the S -35 's depends greatly on duced in the 1950's -is booming well into impressive. their placement. The S -35's, perhaps be- its middle age. There is one reason why The S -35 is a two -driver system. A 130 cause of their rear-facing ports, seem even bookshelf speakers are so popular: They mm (5 -inch) full -range driver provides the more sensitive than most. For optimum allow flexibility in placement while still bass and midrange frequencies, while a imaging, Canon recommends positioning providing good performance, although 19 -mm (3/4 -inch) dome tweeter is sus- the speakers six to ten feet apart and tilted they can't produce the deep bass response pended in front of the bass driver and pro - inward toward the listening area at an an- that only large, floor-standing speakers vides the treble frequencies. The rated gle between 30 and 45 degrees. and subwoofers offer. frequency response is 70 Hz to 22 kHz, We auditioned the speakers in an assort- Canon U.S.A. 's S -35 loudspeakers ±3 dB. ment of locations with an assortment of designed - and built by Canon Audio in the The S -35's tweeter is cooled with ferro- program material. U.K.-represent In general, they per- Canon's first entry in the fluid, which helps to give the speakers a formed quite well. They did suffer from the U.S. audio market. They are also unlike power-handling rating of 75 watts max- lack of deep bass that is inherent in small any speaker system that has come into the imum. The minimum power recom- speakers, but when they were placed near Gizmo offices. First, they don't look as mended is 10 watts, with 50 watts room boundaries, the bass was firm and much like speakers as they look like over- recommended as optimum. An overload the speakers' response was balanced and sized black mushrooms. A black matte - protector, which integrates the speaker even well into the treble range. The sound finished dome is suspended over a conical current over time (it gets hot, in other was neither boomy nor boxy. black plastic base. Nowhere is there a words), is provided to prevent damage to What was truly impressive about the grille or grille cloth to be seen, or any the speakers from misuse or amplifier mal- speakers, however, was their wide imag- other indication that these mushrooms are function. In an overload condition, ating. When positioned properly, the acous- actually speakers, and not some funky tenuators will markedly reduce the volume tic mirrors truly did spread the stereo modem sculpture. of one or both speakers. The protection image so that it was not confined to a small In reality, the speaker drivers are circuit automatically resets when the fault "hot spot" at a location that would be at mounted in the top dome. They don't fire is corrected. However, the protection sys- the apex of a triangle (with the speakers at into the room. Instead -in an unusual de- tem has a "memory," and according to the the two other corners). Instead, we were parture from standard speaker design - manual, it will operate at progressively able to walk across the room without being they fire downward. That is the secret to reduced levels if it suffers repeated over- aware of the speakers' placement, yet the the wide image that the speakers are able load. stereo performance was superb throughout to produce. You could say that it's done The speakers' sensitivity is rated at 88 an angle of better than 90 degrees. with mirrors. The conical black plastic dB (for 2.83 volts at 1 meter), and their The imaging performance truly showed base is not there just for aesthetic pur- nominal impedance is six ohms. Their itself when we pressed the speakers into poses, but is an acoustic mirror that re- total harmonic distortion (THD), mea- service as part of our video system. The flects the drivers' outputs into the mom. sured between 120 Hz to 12 kHz, is rated at 5 -35's are well suited to act as video The enclosure, which is built of plastic less than 0.3%. speakers because they are magnetically and internal zinc, has two rear- facing The S -35 loudspeakers are designed for shielded. They can be placed directly next ports. The ports are located in the back of a variety of applications, and they have a to a video monitor without causing any the top dome. However, the enclosure variety of mounting options. Dedicated distortion.

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sion path to eliminate the introduction of clock jitter. Because of that, the analog signal path, which we would normally consider to be more prone to the effects of interference, is longer. Perhaps the longer signal path is not an important factor because the DX -1 "avoids the use of performance- limiting integrated circuits, using only premium -grade, discrete components in its analog section." Operating the DX -1 is straightforward. The three buttons to the left of the display are to open the disc tray, and to play and pause the disc. To the right of the display are buttons to select the next or previous track, and a welcome but somewhat unusual stop function. The stop mode allows you to keep the DX -l's power on continuously without running the spindle motor needlessly. The display shows the track number, the track time (elapsed or remain- High -End CD is filtered to reduce the possibility of elec- ing) or disc time (remaining), and a 15- tromagnetic interference (EMI) entering track "music calendar." for the Masses the unit from the power line. The trans- The display can be read easily from di- former is encased in a potting resin that is rectly in front, but beomes indistinct at an designed to reduce the emission of EMI angle. Unless you mount the CD player at DX -1 COMPACT DISC PLAYER. Man- interference that can affect low -level sig- eye level, expect to do some neck craning ufactured by: California Audio Labs, nals. An internal steel subchassis isolates to see the display. If you prefer not to be 16812 Gothard St., Huntington Beach, the transport mechanism from external distracted by the glowing display, you can CA 92647. Tel: 714- 841 -1140. Price: vibration to reduce potential read errors. turn off the backlight with a push of the $595. Even the disc clamp is specially designed LIGHT BUTTON on the remote control. to support one third of the CD's surface. The remote control provides access to a Choosing a CD player can be one of the The lenses in the DX -l's optical system number of other functions as well, includ- most difficult decisions you'll have to are glass, rather than the usual plastic. ing two -speed audible search (backward make about your audio system. CD players They are mounted in a diecast housing to and forward), and random track play. The have, in a sense, become the great democ- improve heat dissipation, and the assem- display's time mode can be changed only ratizer of hi -fi audio reproduction. The re- bly is transported by a linear worm -drive. from the remote, and tracks can be ac- production quality that was once available The tracking, focusing, and rotational cessed directly from the numeric keypad. only to enthusiasts who could afford to lay speed servos are digital instead of analog, The remote also allows the DX -1 to be out many hundreds, or even thousands, of which, according to California Audio programmed. Up to 20 tracks can be pro- dollars is now available to anyone who can Labs, provides a tenfold improvement in grammed to play in a chosen or random afford an inexpensive CD player. servo speed and accuracy. Thanks to the order. Finally, the remote allows access to But are all players CD created equal? No improved servo accuracy, the DX -1 is said a music scan mode in which the first 15 they are not, although the differences sep- to reduce the amount of error correction seconds of each track on the disc is played. arating the best from the worst are less that is usually required to compensate for The rear panel of the DX -1 offers an IEC conspicuous than with other audio equip- lost bits. power connector, standard phono jacks for ment. Some differences, such as quality The digital -to -analog converter (DAC) left- and right- channel outputs, and a dig- physical construction, are easily evident. in the DX -1, custom designed for Califor- ital audio output. The digital output sup- Some differences are hidden, including nia Audio Labs by Matsushita, is a delta- ports connection via a 75 -ohm coaxial the attention paid to the interior con- sigma (1 -bit) design with 16-bit resolution. cable; an optical output is not provided. struction that increases a CD player's im- (One-bit converters can provide reduced Does all the extra care taken by Califor- munity to bumps. Some differences are quantization errors as compared with nia Audio Labs show up when listening to subtle- reduced error rates that improve multi -bit converters, yet they don't require the DX -1? Although we listened in a wide the accuracy of reproduction, for instance. expensive calibration and trimming.) variety of situations, with different ampli- When we first unpacked the California According to a company spokesman, fiers and speakers, we auditioned the DX -1 Audio Labs DX -1 single -disc CD player, the DAC design was chosen to allow the mainly in one comfortable listening room. we noticed that it had a look and feel that high -frequency signal to be equalized in The music we listened to was varied, rang- indicates quality. Housed in an attractive, the analog stage. The intent of the equal- ing from a Glen Gould recording of Bach's black metal cabinet with a plastic front ization is to simulate the frequency re- Goldberg Variations to recent recording of panel, the DX -1 has a balanced look. The sponse of a moving -coil phono car - jazz saxophonist Henry Threadgill, and CD drawer is at the center of the upper tridge,and thus give the DX-1 an analog - everything in between. front panel, above the unit's display. Six like sound. We're not sure how to recon- The DX -1 seemed to disappear from the pushbuttons are arranged in elegant sym- cile that intent with the DX -l's virtually audio -reproduction chain in a way that metry, with three on each side of the dis- flat frequency response. many CD players don't. All that was left play. The power button is at the upper left. Unlike most CD players, the DX -1 has was its very musical performance. We Some signs of the unit's quality aren't the DAC circuitry mounted to the transport weren't listening to a CD player, we were seen by the end user. For example, the AC mechanism. The rationale for that is to listening to the music. What more can you line (which enters via an IEC power cable) reduce the length of the digital transmis- ask from a CD player?

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Raveling Scale on How do you keep track of your weight when you need to most -when you're Norix the road, eating in restaurants three times a day? Pack the MiniScale from International, Ltd. (575 Grove Street, #C9, Clifton, NJ 07013). Weighing just 13 ounces, and measuring a compact 41/2 inches in diameter, the MiniScale fits easily foot on into any suitcase, briefcase, or gym bag. When you place the ball of one and lean the scale (while supporting yourself lightly with both hands on the wall) one forward, the microprocessor-based device precisely determines your weight in time second. By pressing the mode button, the weight display is replaced by a display -the MiniScale does double -duty as a travel alarm clock. Price: $69.95.

Digital Travel Scale /Alarm Clock Outdoor/Indoor Speaker Intended for both indoor and outdoor applications, the Sound Mushroom Model 410 from Recoton (46 -23 Crane Street, Long Island City, NY 11101) is a portable 900 -MHz wireless amplified speaker that takes its name from its distinctive domed enclosure. Powered by a rechargeable sealed lead -acid battery that lasts for more than 10 hours on a single charge, the speaker can be used far from the nearest electrical outlet. Its high- impact copolymer enclosure sheds rain, is indifferent to heat or cold, and resists both cracking and discoloration. The Sound Mushroom has its own on/off switch, volume control, and a tuning control that locks precisely on the 900- MHz-range frequency used by the included transmitter to send signals to the speaker. When the signal is locked in, an LED indicator glows to confirm it. Price: $199.99.

Home-Theater TV North The 35 -inch RCA 3571MB from Thomson Consumer Electronics (10330 Meridian Street, Indianapolis, IN 46290 -1024) couples big -screen action and the SRS Sound Retrieval System with convenience features designed to enhance viewer enjoyment. The SRS system "fills the room with sound without the aid of external speakers, wires, or other equipment." The set features Thomson's optimum -contrast dark -glass picture tube and 110 -degree very high performance (VHP) system. Those two technologies combine to provide outstanding picture contrast even in brightly lit rooms. Convenience features include color-coded monitor panels for easy connection of video and audio components; advanced color picture-in-picture, which allows the viewer to adjust the inset picture size and position; and channel guide, for previewing up to 12 channels at the same Recoton Sound Mushroom Outdoor Indoor Speaker time. A remote -controlled on -screen menu system visually guides consumers through TV features and operations. Price: $2199.

Television Antennas The four new television antennas in Jasco Products' (311 N.W. 122nd, Oklaho- ma City, OK 73114) Optima line are said to feature the same advanced microwave technology used in military radar systems. As Jasco explains it, conventional indoor antennas receive only the horizontal component of incoming electromagnetic waves, while Optima antennas use a circularly polarized element to receive signal the vertical component as well. Supposedly, that results in up to twice the line reception, with no need to aim the antenna at the incoming signal. The includes the amplified Model 8229, which is equipped with a built-in "Op- tiAmp," a tilt/swivel hinge, and black dipoles. The antenna features a stabilizing four suction -cup base supports for secure placement on any flat base weight and Jasco Optima Antennas 19 surface. Prices: $24.99 to $89.99.

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CliklCase CD Holder Recently awarded a Bronze prize in the 1994 Industrial Designers Society of America Industrial Design Awards Competition, the Clik!Case CD 12 carrier provides maximum protection for 12 CD's without their jewelbox cases. The Clik!Case has a molded plastic outer shell that is "virtually indestructible," according to Outer Circle Products, Ltd. (860 West Evergreen Avenue, Chicago, IL 60622). Six individually hinged trays hold two discs each and flip up or down for easy disc selection. The trays lock to hold the CD's firmly in place. A center grip raises the discs above the tray surface for easy pop-up release. Price: less than $10.

Rubbermaid Office Furniture When you think of Rubbermaid office products, what probably comes immediately to mind is the traditional "round file cabinet" in which you toss trash. Think again. Rubbermaid now furnishes complete offices, with its line of SnapEase ready-to- assemble CliklCase C012 CD Storage Case furniture. The line, marketed by a division of Rub- bermaid called MicroComputer Accessories, Inc. (9920 La Cienega Blvd. , In- glewood, CA 90308 -7032), includes a 46 -inch computer desk, a matching hutch, and a printer cart. Aimed at home and small offices, the furniture features contemporary design, scratch -resistant materials, and simple assembly. SnapEase products assemble with a snap -lock mechanism that requires no tools. The desk, Model 7300, can hold a computer, monitor, and printer. It has a full -width, glide - out keyboard drawer that includes a storage area for diskettes. The desktop inlay is reversible; one side is solid gray, the other has a maple woodgrain pattern. The hutch, Model 7305, frees up desk space by providing extra storage for manuals and supplies, and features a movable shelf. The Model 7105 printer cart has two rear wheels and nests beneath the desk when not in use. Prices: desk: $299; hutch: $89.95; printer cart: $59.95.

Video -GameSaver Don't you hate it when you're "killed" while playing a high level of a video game, and then have to play through all the lower levels again to get back to that point? SnapEase HDme -Office Furniture The GameSaver from Naki International (Century City North, 10100 Santa Monica Blvd., Suite 1400, Los Angeles, CA 90067) is a patented, plug -in cartridge that allows Sega or Super Nintendo players to pinpoint, save, and return to exact moments in a game to conquer new levels faster and eliminate frustrating, repetitive game play. For example, if a player conquers the first three levels of a game and keeps losing at the same obstacle in level four, he simply pushes the GameSaver button to mark and return to that spot. Even if the system is acciden- tally unplugged, the cartridge will save the instructions. GameSaver plugs into the video game cartridge slot and then any game can be inserted into the GameSaver cartridge slot. The GameSaver unit can even be transferred to another Sega or SNES system without losing the data. The point saved is remembered for up to 30 hours using four "AA" batteries or a Game Boy- compatible rechargeable battery pack. Price: $49.99.

Personalized Mouse Pads You can get your favorite pictures out of your wallet and onto your desk with a Personalized Mouse Pad. Send your photograph, drawing, or computer art to V.I.P. Communications (P. O. Box 35790, Tucson, AZ 85740), and they will professionally reproduce your image on a mouse pad using state -of-the -art laser printing technology. Computer artwork can be reproduced directly from postscript files. You can also advertise your business by putting the company's logo an mouse pads that are distributed to new or existing clients. All original photos, art, or disks will be returned with the order. Price: $19.95 each in small quantities; 20 Personalized Mouse Pads large orders are discounted.

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Motion Sensor Security Light Bell- shaped lamp holders add a distinctive look and increased lamp protection to the Reflex Designer Motion Security Light Model SL-5315 from Heath Zenith (455 Riverview Drive, P. O. Box 1288, Benton Harbor, MI 49022). The fixture senses heat in motion, and produces a sudden shower of light to startle intruders or unwelcome guests. A selectable dusk timer turns lights on for up to four hours after dusk. Users can also turn the lights on at night from a standard wall switch. At daylight, the sensor resets the unit to the automatic motion -sensing mode. Another safety feature is the selectable security flasher, which sets the lights when motion is detected in the sensor's field. The user can choose the flashing Reflex Motion -Sensor Security Light amount of time (from one to 20 minutes) before the unit automatically stops flashing. The security light controls two 150 -watt floodlights and detects motion as far as 70 feet away. Three overlapping detection zones provide an effective coverage area of up to 4.000 square feet. Price: $35.

Cordless Digital Answering System The Cordless Digital Answering System 5650 from AT&T (Consumer Products Division, 5 Wood Hollow Road, 3L11, Parsippany, NJ 07054) combines a cord less telephone and a digital answering system in one unit. Users can retrieve messages remotely from either the cordless handset or any touch tone phone. The answering system records incoming messages and an outgoing announcement on a memory chip with 26 minutes of recording time. The 10- channel cordless telephone features a speakerphone with dial in the base, two -way page and intercom, and nine -number memory. Price: $259.

Plain -Paper Printer/Fax/Copier Home offices are notoriously short on space, so multifunction devices are particularly appealing. The PFC Model KX -SP100 from Panasonic Communica- AT &F Digital Answering System /Cordless Phone tions & Systems Company (Two Panasonic Way, Secaucus, NJ 07094) fits the bill, serving as a plain -paper printer, Fax, and copier in one compact unit. With its unique, upright design, the PFC can fit on a desk beside a computer and doesn't require additional office furniture. The unit's telephone /Fax switch eliminates the need for a dedicated phone line for the Fax. The Energy Star-compliant PFC saves on electricity by cutting down the number of office machines drawing power. And having the copier, Fax, and printer right on the desk allows workers greater privacy and control over their documents. The printer is a full- featured, laser-quality (300 - dpi) personal page printer with a 70 -page input tray that holds either letter- or legal -sized paper. The plain -paper Fax features a 10-page automatic document feeder, auto -reduction mode, and a journal -print function that lists the last 35 transmissions and/or receptions. It connects to a desktop phone and such Fax functions as speed dial and redial are accessed directly from the phone's handset. The PFC will accept an incoming Fax while the printer is in operation and store up to 18 pages (or up to 104 pages with optional RAM expansion boards) in memory for later retrieval. As a copier, the PFC features a 10-page automatic document feed; medium, light, and dark settings; and fine and halftone modes. Price: $999.

Panasonic PFC Plain -Paper Printer /Fax, -Copier Entry-Level AM/FM Steno Tuner The 7X-480 is the first entry-level AM/FM tuner from Yamaha Electronics Corporation, USA (6660 Orangethorpe Avenue, Buena Park, CA 90620) to feature rotary electronic tuning. Other convenience features include preset ex- change, which allows a user to easily change or reassign any or all of the 40 preset stations, and a three -way, multi -status station name display. Incorporating Yamaha's "Alpha" (Absolute Linear Phase IF) circuitry, the TX-480 offers improved selectivity without sacrificing linearity. High adjacent- station rejection is important in urban areas where stations might impinge on each other's pre- Yamaha AM /FM Stereo Tuner 21 scribed frequency. A wireless remote control is available optionally. Price: $199.

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"Bodysonic" Car-Audio Speaker Pioneer Electronics' (2265 East 220th Street, Long Beach, CA 90810 -1639) BSS -C1 Bodysonic Speaker System allows consumers to "feel" the music playback of their car-audio systems. The speaker, which is designed primarily to improve bass sound reproduction and listening enjoyment in the noisy environments found in convertibles, hatchbacks, and sport utility vehicles, fits onto the backs of driver and passenger seats. The system consists of a small, easily installed amplifier unit, a remote control, and the seat -fitting speaker pad. Price: $300.

Camcorder with Built -In Color Monitor Sony's (1 Sony Drive, Park Ridge, NJ 07656) CCD- FX730V Handycam 8mm camcorder allows users the choice of framing their shots on a three -inch color LCD screen or by using the camcorder's traditional viewfinder. Video footage can be played back immediately using the built -in LCD screen and speaker, or by connecting Pioneer Bodysonic the camcorder to a TV to view the video on a larger screen. The LCD Speaker monitor is mounted on the side of the camcorder, where it can be folded out when needed. The screen can be tilted and turned, allowing users to capture shots from difficult or unusual angles. When not in use, the LCD folds flush against the side of the camcorder. The CCD- FX730V also features an optical 12:1 variable -speed power zoom; four-mode program auto- exposure control; age insert, an electronic calendar that can automatically update and superimpose age information for up to three children; quick record, to begin recording in one -fifth of a second; an audio/ video digital fader; and AFM hi -fi sound. Price: $1099.

Multi-Room Music Center The Beocenter 9300 from Bang & Olufsen of America, Inc. (1200 Business Center Drive, #100, Mt. Prospect, IL 60056) is a remote -controlled, compact Sony Handycam with LCD Screen music center that offers multi -room communication. It contains an FM/AM radio, a stereo amplifier, an auto -reverse cassette recorder, and a compact -disc player in a single, elegant cabinet. The slender, tapered cabinet, which is surfaced in highly polished aluminum and black glass, features "sensi- touch" glass panels instead of conventional buttons or knobs. Proprietary operational menus controlled by a microcomputer work as a "guided tour" of all functions including timer programming -with 15 events for timed play and recording of all internal sources -for one -time or multiple programs for different times and days of the week. Two pairs of passive Beovox loudspeakers or up to ten pairs of Beolab powered speakers can be connected to the Beocenter 9300 for home -theater or multi -room use. Line -in and -out connectors allow the addition of accessory equipment such as surround sound processors. Price: $2995.

Bang & Olufsen Beocenter 9300

MPEG Multimedia Plug-in Board ReelMagic from Sigma Designs (46501 Landing Parkway, Fremont, CA 94538) is the first consumer-priced MPEG playback card for the PC. Based on the MPEG standard for compression, ReelMagic decompresses video and audio in real time, allowing up to 74 minutes of full- screen, full -motion video and CD- quality audio sound to be played from a standard CD-ROM drive. More than 50 ReelMagic- compatible titles will be ready by Christmas. Scheduled for shipping this past summer were 20 new titles, including Space Ace from ReadySoft, Return to Zork from Activision, Lord of the Rings from Interplay Productions, World Cup Soccer from CD- Vision, Sporting News Football from Compton's NewMedia, and World Atlas and 20th Century Video Almanac from The Software Toolworks. ReelMagic can also play Video CD movies on 5 -inch discs. Price: $449 with 16 -bit DSP 22 Sigma Designs ReelMagic sound controller.

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www.americanradiohistory.comAmericanRadioHistory.Com TELEPHONE LINE ANALYZER

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Buy it or build it, because you'll need one in this information age.

While the telecommunica- Tel. 708 -541 -3800). It comes with a can cause problems for some equip- tions revolution started way thorough tutorial on phone tech- ment. back when the telegraph nology, and everything you need to Second, a "ring test" determines was hot, it is far from over. The fact that build an analyzer. For those who whether a phone's ringer, the phone Fax's and modems are migrating from would just like to use the analyzer with- line, or line loading is to blame for a the work place to the home is evi- out having to build it or understand its lack of audible ringing. To do that, the dence that the battle field is only get- workings, it is available pre -as- meter is used to rate the quality of the ting larger. sembled, without a tutorial, for $33.25 incoming ring signal. That test is very If your home, office, or home -office as the Model 400. useful, as it is easy to misconstrue communications hardware is growing Regardless of which model you missed calls as a telephone- compa- as a result (an answering machine choose, the analyzer is novice- friend- ny problem, when in fact you've just here, a Fax there), you are likely to ly. For all but one of the tests it per- got too many telecom goodies on the encounter an installation problem forms, you simply plug a phone into line. sooner or later. For example, you the analyzer's front -panel jack, and Third, a "loop test" helps you find out might load the phone line with too plug the analyzer (which comes with if the problem is in your internal wiring many devices. Its also possible that its own cord) into a phone -line jack. It or in the outdoor phone line. That is one of your phone -line jacks has its only has one control: a two- position obviously a must for determining the polarity wrong and will cause trouble switch that you set according to which responsible party. with a newly purchased device. test you're performing. The test indica- Last, a "telephone-cord test" allows Of course the phone company will tors are a simplified meter (which has you to check phone cords for loose gladly service your needs, but you colored "regions" instead of a num- connectors and such. For that, the sus- must pay an extra monthly fee, every bered scale) and an LED used to indi- pect cord is left connected to the wall month, whether you place a service cate polarity. jack of the phone line, and the other call or not. Alternatively, you can end is plugged into the analyzer's maintain your internal phone lines Use. To give you an idea of the ana- front -panel. Next, the cord of the ana- yourself. For that you'll need two lyzer's usefulness, let's discuss the tests it lyzer is plugged into the phone. If the things: some idea of how a phone performs. First, there is a "line test" that meter reading varies while the sus- works, and a phone -line analyzer. detects overloading from a defective picious phone cord is jiggled, the You get both of the above with the phone or shorted wiring. During that cord is bad. Elenco Model 400K Telephone Line test, an overload is indicated by a low To expedite the tests, the documen- Analyzer kit, available for $21.50 from reading on the meter. Also, if the unit's tation contains both simplified and Elenco Electronics (150 West Car- polarity LED lights up, it means the detailed instructions. The simplified in- penter Ave., Wheeling, IL 60090 -6062; phone -line wires are reversed, which (Continued on page 89)

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www.americanradiohistory.comAmericanRadioHistory.Com THINK TANK

By John J. Yacono. Over the last three to flow (like current) from That relationship is called

Technical Editor, months, I covered the outlet of the pump (the "Ohm's Law" and resistance Windows Magazine enough ground to explain negative battery terminal), is measured in units called the concepts of current through the pipes (wires), "ohms." Both are named in and voltage (or potential), and back to the pump's honor of a pioneering sci- as well as other electrical inlet (the positive battery entist. That law is perhaps phenomena. As promised, terminal). the most fundamental rule this month I'll explain resis- Now let's upset that har- in all of electronics. All hob- tance and its relationship Temperature.. to monious picture by placing byists commit that rule to current and voltage. To a valve somewhere along memory as a matter of Controlled please the more savvy the pipe network. If we par- course. readers, I'll also present tially close the valve, the In next month's column Circuits letters containing some current decreases and the we'll discuss our first corn - temperature- sensing cir- pressure difference be- ponent: the "resistor." I'll cuits. tween the pump's inlet and describe its effect on current flow and some of the 120 -VAC FAN SUPPLY different types of resistors ó you're likely to encounter. +12v Now its letter time. W n R5 R7 R8 ks1 FAN ACTUATOR 7' 10K 1.5K 47K In a building R3 with high ceilings, 10K LEDI R2 which is heated (R.S.271-110) 500K with a wood -burning 2 stove, FAN RUN a R1 7 TIME ceiling fan was installed 10K to circulate the heat. But 6 10 -TURN the fan had THRESHOLD to be manually switched on when the stove R9 was lit. Since I'm a bit lazy R6 1.5K at times, I built this circuit R4 10K Cl ÿ MOTI 10K 50 LED2 CEILING (see Fig. 1) to automate the R.S.271-110) FAN fan.

The op -amp, U1, is placed in a comparator Fig. 1. This circuit measures temperature differences, not temperature. Once the difference passes a certain threshold, the timer is triggered, activating the solid-state relay. configuration with two thermistors -one located at the ceiling, one at the floor. The Let me start by re- intro- outlet increases, In fact, the IC senses the temperature ducing last month's "water - change in pressure is pro- difference between the in -a -pipe analogy." In that portional to the change in ceiling and floor, but is un- analogy, water represents water current. The action of affected by the overall electrons, the flow of water the valve on water current room temperature. When is current, a series of pipes (or electron current) and the temperature differential are like a wire, a water pressure (i.e., voltage) is so increases, the upper ther- pump is a battery, and the precise, we can give it a mistor will decrease in difference in pressure be- name. In fluid dynamics it's resistance, eventually caus- tween the pump's inlet and called "pressure head," but ing the voltage at pin 2 of outlet is in the battery's electronics it's called "re- U1 to exceed that at pin 3. voltage. sistance." That causes the output of Let's say the pump's inlet Of course, the rela- U1 to go low and trip the and outlet are connected tionship between timer, which adds hysteresis to the ends of a series of resistance, current, and volt- to the op -amp's output, pipes. If the pipes and age didn't go unnoticed by preventing the motor from pump are full of water, turn- early scientists, and led to chattering. When tripped, ing on the pump (battery) the famous equation: the timer activates the relay, causes the water (electrons) R= E/I which activates the fan.

www.americanradiohistory.comAmericanRadioHistory.Com +12V R8 NTC 3K(fò25°C R2 NEUTRAL -WHITE 10K S01 SET TO AC SOCKET POINT 120-VOLTS AC FOR HEATER o BLACK -HOT

D4 +12V 1N4004,

R7 , 33000 U2 D5 D2 K1 AN25 1N4001 1N914 5 10A 'M 12V D1 R1t 1N914 4700 a1 R10 LEDI 2N2222 3300 O C2 R12 100KR6 100 4.7K V circuit will turn Fig. 2. Using a bridge circuit to provide an accurate activation temperature, this set by R2. Use a on a heating unit or other device when the temperature drops below the trip point 10k resistor in place of the thermistor to calibrate it for 32 °F activation.

turn -on operation. Capaci- the thermistor's value of ap- The vertical position of The circuit might be tor was added to proximately 10K at 32° F. the thermistors, and the useful for me. I have gable C2 prevent relay chatter or That way you don't have to threshold trim control (R1), fans, controlled by a Ther- the circuit slowly wait for freezing tempera- how sensitive the mostat, that remove hot air buzz as will affect unit. when The comes on. Make sure, for tures to set the circuit is to a temperature from my attic is heater applications, that -Roger W. Hamel, differential. The timer con- temperature in the attic The The- the relay contacts can han- Cedarville, MI trol (R2) will affect how high. They work on Very nice work. I would ory that There is cooler air dle the current required by often the system cycles as recommend that the cal- under The eaves That will your heater. Also, precision the room approaches tem- the (1 %- tolerance) resistors ibration resistor replace perature equilibrium. replace The hot air. Of the thermistor at the far end of bit of course, if the air entering should be used for Although I'm sure a the bridge isn't That much bridge circuit. the cable, not at trial- and -error adjustment . The eaves with the fine end. The reason for that is for a sin- cooler, it's hardly worth Be careful will be necessary, the cable resistance thermistor wires. I used small to take gle floor, the thermistor keeping the fans on. The heat -shrink tubing and ep- into account during cal- connected to the 12 -volt circuit could keep the fans to attach it to an old ibration. Also, be sure to use supply should be placed from activating unless it's oxy point -pen case so the heavy -gauge wire for all AC near the ceiling, but away truly beneficial. ball- thermistor just protrudes out connections as appropriate. from the fan, and the other end. At the other end, I thermistor should be FREEZE SENSOR one attached approximately 6- THERMOSTAT CIRCUIT placed beneath it, a few This circuit activates a 2- conductor cable I have been experiment- feet above the floor. heater to hold the temper- feet of to mate ing with temperature - 32°F. I with an RCA plug -David L. IGng, ature a little above Mich- with J1. In operation, don't control circuits and came Chicago, IL use it during Northern the probe directly up with this differential ther- Although David didn't igan winters to prevent position too close to mostat. With the compo- provide more information freezing in water pipes, etc. in front of or the heater, as that causes a nent values shown (see Fig. on the solid-state relay he Diodes D3 and D4, which short cycling rate. 3), my thermostat operates used, Chats not too much of are forward biased, estab- For quick calibration, re- between 32° and 86 °F. a drawback since you'll lish an operating voltage of place the thermistor I have used Iwo sections have to specify one to about 1.65 volts across the with a 10K 1% of an LM324 quad op -amp meet your own needs any- bridge. That ensures that assembly resistor connected across configured as comparators. way. Just find one that the small thermistor bead RCA phone plug, then The reference voltage of handles the load current operates without any ap- an set the 15 -turn trimmer po- each comparator is set by you have in mind, and re- preciable self- heating. tentiometer, R2, to just light two multi -turn potentiome- quires a 12 -volt DC input The diodes at the output LEDI. The resistor simulates (Continued on page 70) 29 signal. of the 741 ensure crisp, sure

www.americanradiohistory.comAmericanRadioHistory.Com Countersurveillance

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www.americanradiohistory.comAmericanRadioHistory.Com Build a Telephone -Line Simulator

nated only when the mode Mr. Watson, come BY THOMAS E. BLACK or cycle time is shown; a de- here; I want you. Ever since those coded DTMF (Dual -Tone famous words were spoken Multi- Frequency) digit is over the first telephone in- shown as a value without the strument by Alexander Bell, decimal point. we've discovered unlimited The five modes can be in- uses for the telephone. Now voked by pressing the Mode we can communicate not switch; the active mode is only with our trusty tele- shown in the LED display. The phone, but we can also use modes are summarized as PC modems, Fax machines, follows (the bracketed value answering machines, and indicates the corresponding the like. LED display): But those gadgets have [n.] Normal Ring Mode become complicated, and [A.] Automatic Ring Mode they occasionally break [b.] Beep Tone Mode down. Testing them can be a [c.] Cycle Ring Test Mode real chore, unless you have [d.] Dumb Mode access to multiple phone Use it to test or demonstrate lines so that you can conve- The normal ring mode is niently place test calls. Of telephone equipment, to set used when you want stan- em- course, there are commer- dard telephone- system cial phone -line simulators up your own mini telephone ulation. When you take the -1 phone off - that can be used instead of more. line (main) system, and is heard. If a phone line, but they can hook, a dial tone for twenty cost several hundred dollars. you do nothing a sound is Well, with Ring -It! you can seconds, "reorder" If tone dial any now have a complete tele- heard. you number, the line -2 phone system in a box. Forget about the phone on line 2 automatically seven -digit phone will start to ring. When line tying up your telephone line; simply rings when the phone on line 1 is (test) phone front -panel connect plug in the telephone device that you picked up. The lines are connected 2 answers, the want to check, and do your tests. when both phones are in use, and the LED will light up. keys of All of the standard telephone -sys- conversation ends by hanging up. While you press the DTMF tem features that you need are sup- The flexibility of Ring -It! is provided your phone, the corresponding digit for up to ported. You can ring -up telephones, by a single -chip microprocessor, will appear in the LED display limitations in Fax machines, modems, and answer- which allows us to keep the compo- Iwo seconds. Because of ing machines. Just about anything nent count to a minimum. An on- our display, the * tone is shown as "A" that you can connect to a standard board ring generator provides the and the # key is shown as "P" phone line can be activated with precise voltages required to activate If you attempt to ring the test line it is off-hook, then a busy signal Ring It!. the phone equipment, and a call - and heard. Please note that be- Because the standard telephone - progress tone -generator IC creates will be call progress sounds are generated the normal telephone -related sounds cause it is a one -way device, line 2 ring line 1. (dial tone, busy signal, tinging, etc.), (busy signal, ring signal, etc.). can not be used to shortcuts in the nor- you can even use Ring -It! to demon- There are some to ring strate telephone equipment. Don't Features. Ring -It! has five different mal mode that can be used the ever tie up your home or business operational modes that can be invok- the test line. For example, pressing imme- phone again while you show off your ed through one of the front- panel- main phone's DTMF * key will ring request. The front - telephone products. In fact, with Ring - mounted push switches. There is even diately start the panel Ring switch will also start the It!, ifs almost impossible to tell that you an LED readout that displays the cur- can be used if the aren't using a real phone line. rent mode that is in use. ring cycle, which line's is not DTMF com- You can even connect a pair of The LED display is used to indicate main phone standard phones and create a simple mode, cycle time, and dialed -digit in- patible. mode is perfect for 31 phone system. In that configuration, formation. Its decimal point is illumi- The normal

www.americanradiohistory.comAmericanRadioHistory.Com demonstrating telephone equipment TABLE such as answering machines, Fax sys- 1 -DTMF TONE PAIRS tems, voice mail, modems, and more. Because the standard call -progress Low Group High Group audio tones are heard, your demon- Column 0 stration will appear more natural Column 1 Column 2 to 1209 Hz 1336 your audience Hz 1471 Hz and equipment. Raw 0, 697 Hz 2 3 The automatic ring mode is similar Row 1, 770 Hz 4 5 6 to the normal ring mode, except that Row 2, 852 Hz 7 8 9 in the automatic mode, ringing be- Row 3 941 Hz 0 gins immediately after the line -1 phone is picked up. That operation is Note: In 16 -digit QTMF, there is an eighth tone (1633 Hz, Column 3), sometimes called a "Ring -Down line" by phone -system manufacturers. If either line is off -hook when the other is phone must be plugged into the Only Memory (ROM), and digital In- picked up, the Iwo lines will be auto- main line. To start the cycle you must put /Output (I /O) lines. In other words, matically connected together. pick up the phone attached to line 1. ifs a complete computer system that The automatic mode, besides Again, if either line is off-hook when is housed in one IC. being used to test phone equipment, the other is picked up, the Iwo lines will Because the PIC16C57 -XT /P is a is also perfect for use as a front -entry be automatically connected to- computer, it needs software to oper- intercom for home or office use. Place gether. ate. The internal ROM holds the soft- a phone near you and one near your When line 2 answers, your con- ware program, which is called entry. Be sure to post a note near the versation may If begin. line 2 hangs up firmware. The firmware is permanently entry phone that instructs your visitors and the main phone remains off - programmed and is non -volatile, to "lift the receiver for assistance." hook, the test line is automatically which means that it isn't lost when The beep tone mode is specially rung up after the delay time. That cy- power is turned off. The RAM is used by designed for cycle testing answering cle repeats until the main phone is the program for storing temporary machines and other types of tele- hung up. data variables and state conditions. phone equipment. That mode does The dumb mode provides a silent Although there are only 72 bytes of not start until the Ring button or the talk path and allows a manual ring. RAM, ifs more than enough for our DTMF * key is pressed. You will not hear any call progress application. It is not necessary to have the -1 line tones; however, you can converse The firmware -controlled functions, phone off-hook during the beep normally. such as ring generation, tone detec- mode. Whenever line 2 is taken off - Line -2 ringing is controlled by using tion, LED and relay control, etc., are hook the Iwo lines will be automat- the Ring switch or the main phone's * event -driven, so all features work ically connected together and se- a key. The ring signal will follow the key seamlessly together. Unlike simple ries of repeating test tones will be presses. Unlike the other modes, they loop- controlled programs, generated. our soft- do not continue to ring when the keys ware design uses a time -based task During the beep mode, the test line are released. scheduler to control the hardware automatically rings after a short ad- The dumb mode is perfect for test- operations. justable delay (the delay is skipped on ing the basic operation of equip- Installing the firmware into ROM in- the first cycle). If the test line is an- ment. And because you can control volves a process called prom burning, swered, staggered beep tones are the duty cycle (cadence) of the ring and special equipment is used to per- played. Those tones have been de- signal, non -standard equipment can form that task. For those without the signed to keep a voice -controlled an- be tested for ring operation. required equipment or expertise, a swering machine from hanging up. preprogrammed microcontroller is The ring -up cycle repeats (after the How it Works. A schematic diagram available from the source given in the requested delay) until the mode is of the Ring -It! telephone -line simulator Parts List. On the other hand, for those canceled by pressing the Mode is shown in Fig. 1. The circuit's intel- of you who want to "roll -your- own," we switch. ligence is provided by U9, a have made the compiled object - For example, if the delay is set for PIC16C57 -XT /P microcontroller IC. code file, in Intel 8 -bit merged thirty seconds, the device being test- That chip is a member of Microchip (INHX8M) format, available on this ed will be rung -up thirty seconds after Technology's family of high- perfor- magazine's BBS (516- 293 -2283, 8N1). the last answer /disconnect cycle. The mance, low -cost 8 -bit micro - Although the software is copyright test tones will be played as long as the controllers. protected, you are free to download test line is off-hook. If the test line goes A microcontroller is a small, gener- a copy for your personal use. For other on -hook, the delay cycle starts up al- purpose computer chip that con- uses, consult the source given in the again. tains a microprocessor -type, Central Parts List. The cycle ring -test mode provides Processing Unit (CPU), similar to the Getting back to the circuit, U9's most of the features of the beep in one found your personal computer. RTCC input is used to emulate an ad- mode, except that in the former, the However, it also incorporates Ran- justable- time -delay timer. The fre- beep tones are not played and a dom- Access Memory (RAM), Read- quency of the oscillator formed by

www.americanradiohistory.comAmericanRadioHistory.Com i

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Fig. I. Here's the complete schematic for the Ring -It.! telephone -line simulator. The unit its sophistication but keeps circuit complexity to a microcontroller (U9) gives the 33 minimum.

www.americanradiohistory.comAmericanRadioHistory.Com U11 -d, U11 -e, R41, and C24 can be Microcontroller -input RAO monitors DTMF is detected. The microcontroller varied using potentiometer R35. Its re- S2 (ring) and input RA1 is used to read uses that signal to determine when to petition cycle is sampled by the mi- S1 (mode). Software is used to de- decode a new DTMF digit. crocontroller and then translated by bounce those momentary switches, The RB5 -RB6 inputs are used to the software into a 10- to 90- second which ensures that contact bounce monitor the line 1 and line 2 optoiso- end -of -cycle timer. The delay feature does not cause multiple operations. lated, loop- current hook switches (U2 is used in the beep and cycle modes. Under microcontroller control, and U1 respectively). Those act as nor- RBO -RB3 can be configured to read mally open switches and detect Input/Output Control. The micro - (input) the decoded DTMF codes from when the attached telephones have controller's input /output control lines U7. They can also output call -progress been taken off-hook. For example, if are used to monitor the mode, ring, tone codes to U8 or LED codes to U10. line 2 is off -hook, current will flow and hook -switch switches. They also We will discuss the DTMF decoder, through optoisolator U1's input, which control the LED display, line relay, and call -progress generator, and LED in- will force its output at pin 4 low. The call -progress tone generator. terface in just a moment. microcontroller can read the output Those twenty I/O lines are labeled The direction of those four I/O data of U1 and U2 and act appropriately. on the microcontroller as RAO -RA3, bits is also accompanied by micro - The input at RB7 is used to read the RBO -RB7, and RCO -RC7. Under soft- controller outputs RA2 and RA3. Nor- circuit -board mounted, power -up ware control, RA2 -RA3 and RC3 -RC7 mally low bit RA2 is set high to read the configuration jumper, JU1. If the are configured as outputs, RAO -RA1 DTMF values. Normally high bit RA3 is jumper is not installed, Ring -It! will de- as well as RB4 -RB7 are configured as set low to write the current call -pro- fault to the normal (n) mode upon AC inputs, and RBO -RB3 are used as both gress tone code into U8. power up. If the jumper is installed, the inputs and outputs; RC0 -RC2 are un- The RB4 input is normally low, but automatic (A) mode will be used as used. goes to a logic high when a valid the power -up default. .11-71 1

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Fig. 2. The bulk of the circuitry is located on the main PC- board. The foil side of that board is shown here.

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Fig. 3. Here is the foil -pattern for the main board's component side.

output -bit RC5 is used to provide the The RCO -RC2 port bits are unused. play the current test mode and some used by the step -up The RC3 -RC7 bits are configured as of the DTMF tone values (* and #). As 20 -Hz frequency transformer, T2. Because outputs and are used to control the mentioned earlier, the * and # DTMF ring -voltage many foreign phone line relay, ring -voltage generator, and characters are not displayable, so we American and use 20 -Hz ring frequen- CPC pulse. When used in conjunction show them as "A" and "F' companies cies, we have provided the same in with the RBO -RB3 output bits, they can The LED segments are enabled by the Ring -It! design. Note that some send new LED display values to U10, a the addressable latch, W0. The micro - low -end commercial telephone sim- 74HC259 8 -bit addressable latch. controller uses RBO -RB2 to address which of eight LED segments are to be ulators use 60 -Hz ring frequencies be- they are easily derived from the LED Display. Microcontroller output modified. The RC3 output selects how cause AC power line. However, some phone bits RBO -RB2 and RC3 -RC4 are used the LED segment will be illuminated equipment will not operate correctly to control the single- character, seven - (on /off) and RC4 latches the ad- with them. To maintain compatibility segment LED display, DISP1. (Note that dressed value. alt standard telephone equip- the display actually has eight seg- To update the display, the micro - with ment, a software- controlled, standard ments if you count the decimal point.) controller must step through all eight 90 -volt AC, 20 -Hz ring generator is Like most LED readouts, it was origi- bits of U10 and set or clear them as nally designed for displaying numbers required. Of course, that is done so used. The 20 -Hz generator provides relia- 0-9. But by using a combination of fast that it appears to happen as a ring activation for at least Iwo upper and lowercase, and a little single action. Eight 330 -ohm series re- ble standard telephones. The high volt- imagination, it is possible for us to get sistors are used to safely limit the cur- age (approximately 90 volts AC) is a limited number of alphabetic rent into each segment of the display. by T2, a step -up ring -volt- characters. generated transformer, which is driven by 35 We use the alpha characters to dis- Ring Generator. Microcontroller age

www.americanradiohistory.comAmericanRadioHistory.Com ICI 1991 01611IL PRODUCTS CO IM IN USO terrupted for a few hundred millise- REV A TABLE 2-FOUR-BIT Ctil1t' conds after the phone call ends. That causes a current -interruption pulse DIGIT D3 02 that is sensed by some devices such 1 o o as answering machines, which 2 o o causes them to disconnect imme- 3 o 0 1 diately. 4 o 4" 5 0 o Microcontroller port bit RC7 is used 6 o 1 to control the CPC pulse. Normally 7 o 1 low that bit will be set high for about 8 o 0 500 ms to turn on optoisolator U12, 9 1 0 o RING -ITI which shuts down voltage regulator 1 0 t o RC POIJER BORRO U3. Because U3 supplies the talk volt- 1 0 age to the phones, when it tem- 1 1 0 porarily shuts down, the attached phone equipment senses a CPC in- low adequate viewing. To help see 1 3/4 INCHES terruption. The CPC feature can be some very short DTMF digits, the mi- disabled by removing the JU2, the crocontroller extends the viewing Fig. 4. For better performance, the CPC -configuration jumper. time of the last digit for about two power- supply circuitry is located on a seconds. separate board. The foil side of that Line -Connect Relay. While the The DTMF encoding standard de- power board is shown here. phone lines are idle or during line -2 fines up to 16 dual -tone combina- ringup, microcontroller port pin RC6 is tions, but standard phones only push -pull power transistors Q3 and a logic low and relay K1 is de -ener- generate 12 of them. In a telephone, Q4. Because square -wave- derived gized. That places T2, the high -volt- those 12 keys are arranged in four ring voltages are used, some spe- age ring transformer, in series with line rows and three columns, and those in cialized telephone equipment may 2. That allows power for the talk path a given row or column have one tone not respond correctly. However, all and /or microcontroller -controlled in common. standard telephone equipment will ring voltage. For example, if you press the 3 digit, work with the unit. Energizing relay K1 connects the a 697 -Hz tone and a 1477 -Hz tone are Please note that T2 is used "back- Iwo phone lines together and dis- combined. Seven frequencies are in- wards" in this circuit. That is, the low ables the ring -voltage signal path. volved in standard DTMF generation voltage input is at its secondary and The relay is switched whenever port and they are separated into two the output is taken from the trans- pin RC6 is a logic high. groups. The row information is called former's primary. You can monitor pin 12 of U11 if you the low group and has the frequen- have an application that needs to cies that range from 697 Hz to 941 Hz. Calling -Party Control. To help dis- know when the two lines are con- The column information is called the connect some telephone equip- nected. That signal is available at the high group and it covers frequencies ment, Ring -It! uses a method called external- control output (labeled EXT from 1209 Hz to 1477 Hz. Table 1 shows CPC (calling -party control). On most Cra on the schematic) and is a logic the layout of the DTMF tone pairs. phone lines, the phone voltage is in- low when the relay is energized. It DTMF Decoder U7 incorporates could be used to turn on an external switch capacitor filtering to separate audio source, relay, or whatever. It is the low- DANGER -H I 6H VOLTAGE! a and high- frequency tone TTL- compatible signal and can sink or groups. Qualified DTMF digits are de- source about 10 mA. coded into a four bit code as shown in Table 2. DTMF Decoder. Decoding the dialed phone- number digits is a simple Call- Progress Tone Generator. exercise because of the use of the Phone -company generated sounds industry- standard M -8870 DTMF tone - that are heard on the phone, such as receiver for U7. That popular IC is dial tone, busy signals, telephone made by the Teltone Corporation, ringing, etc., are considered comfort Mitel Semiconductor, and others. tones. They are present only to con- The receiver decodes only DTMF - firm the progress of the telephone type telephone digits; rotary- pulse -di- call. Although foreign countries use aled digits are ignored. The DTMF fea- similar tones, they are slightly different frfil ture allows you to conveniently test than those heard in the U.S. In Ring It!, the tone dialing feature of your phone the comfort tones are largely pro- H-1 -3/4 INCHES equipment. duced using U8, a Teltone Corpora- As long as a DTMF tone is present tion M -991 call -progress tone- gener- Fig. 5. The component side of the power the display will show its value; speed ator chip. board is shown here full size. dialers may operate too quickly to al- Actually, Ring -It uses both software

www.americanradiohistory.comAmericanRadioHistory.Com PARTS LIST FOR THE TELEPHONE -LINE SIMULATOR XTAL2- 3.5795 -MHz crystal, HC18 SEMICONDUCTORS R11, R22 -100 -ohm or HC49 package JI, J2 -RJI1 6/2 Ul, U2, U12- PS2501 -1 optoisolator R12 -not used or 6/4 modular telephone jacks (NEC), integrated circuit R14- 100,000 -ohm, trimmer FI-0.5 -amp fuse, 5 x 20 mm U3- LM317T 1.2 -37 -volt adjustable potentiometer, PC mount Printed- circuit boards, IC sockets. regulator, integrated circuit R15, R16, R24, R27, R28, R34, right -angle socket, fuse clips U4- LM7812 12 -volt regulator, R41- 10,000 -ohm (Keystone 3521 or similar), AC integrated circuit R21- 300,000 -ohm line cord and plug, enclosure, heat U5- LM7805 5 -volt regulator, R30 --2.2 -ohm sinks, wire, solder, etc. integrated circuit R35- 10,000 -ohm, potentiometer, U6- LM358N low -power dual op- panel -mount. linear-taper circuit parts are available amp, integrated CAPACITORS The following Digital Products Company, U7 -M -8870, CMOS DTMF Cl, C4, C5- 0,47 41F, 50- from: Folsom, CA receiver (Teltone Corporation), WVDC,radial -lead, electrolytic 134 Windstar Circle, Tel. /Fax: -916- 985 -7219: integrated circuit C2, C3, C6, C23- 10 -p.F, 16- 95630; kit, including U8 -M -991, CMOS call -progress WVDC, radial -lead, electrolytic Complete Ring -It! ( Teltone), integrated preprogrammed microcontroller, tone -generator C7, C8- 470 -p.F, 35 -WVDC, radial - circuit lead, electrolytic PC -board set, relay, transformers, 8 -bit capacitors, seven - U9- PICI6C57 -XT /P CMOS C9 470 µF, 50 -WVDC, radial -lead. IC's, resistors, microcontroller (Microchip electrolytic segment LED socket, circuit etc. (case not Technology), integrated CIO -C13. C16, C18-C21- 0,1 -µF. documentation, Basic Ring -It! U10- 74HC259 or 74HCT259 50 -WVDC, radial -lead. included); $145.00. set, CMOS addressable latch, monolithic -ceramic kit, including PC -board integrated circuit C14, C15, C17 -27 -pF ceramic -disc, programmed microcontroller, inverter, $53.95. Ull- 74HCT14 CMOS hex see text complete documentation; circuit Transformer/relay kit, including integrated C22- 2200 -µF, 16 -WVDC, axial - Hard - QI, Q2- PN2222 NPN transistor lead, electrolytic Kl, TI, T2, and T3; $38.95. Ul, U2, Q3- TIPI10 NPN Darlington C24 0.01 -p.F, radial -lead, polyester to -get IC kit, including transistor U7, U8, U10, Ull, U12; $24.50. Q4 TIPII5 PNP Darlington ADDITIONAL PARTS AND Printed- circuit board set; $34.95. /P transistor MATERIALS Programmed PIC16C57 -XT 50 PIV, bridge rectifier (licensed copy); BRI -I amp, KI -DPDT relay, 12 -VDC coil, DIP microcontroller - LED D1, D9-1N914 or IN4148 general Package. P &B T83SI1D212 -12, $20.00. Seven -segment purpose silicon diode Aromat DS2YE- S- DC12V, or socket; $3.75. Complete D2- D8- IN4001 silicon rectifier similar documentation package with diode SI. S2 -SPST switch, normally schematic; $6.00. Software disk, DISPI -7- segment LED, 0.56 -inch. open, momentary- contact RI.OBJ object code, INHX8M common anode, RH decimal point pushbutton, panel mount format (disk provides single -use LEDI --Green LED, Tl 3/4 size TI- Telephone -coupling transformer, license; specify 3.5- or 5.25 -inch 600- ohm:600 -ohm, PREM size); $8.00. Please add $6.50 RESISTORS ($14.00 Canada) to all kit orders (All fixed resistors are 1/4-watt, 5% Magnetics SPT130 or equivalent and $5.00 ($9.50 Canada) to all units unless otherwise specified.) T2-Ring transformer, split bobbin, component/documentation/software R1,R9 ,R17 -R20, R26- 100,000- dual 115 -VAC primary to dual 6.3- orders for shipping and handling. ohm VAC secondary, Magnetek/Triad Other countries, please write /Fax R2, R10-75 -ohm FSI2 -200' or equivalent for shipping information. R3, R13, R23, R29-1000 -ohm T3 -AC power transformer, split California residents must add local R4, R6-220 -ohm, 2 -watt, metal bobbin, dual 115 -VAC priamary to sales tax. Checks, money orders, oxide dual 14 -VAC secondary, Magnetek/ Visa, Master Card, and Discover 300 -ohm, 2 -watt, metal oxide Triad FS28 -200 or equivalent R5- accepted; checks must clear before R7, R25, R31 -R33, R36-R40 -330- XTALI -4.00 -MHz crystal, HCI8 or shipping. Payment in U.S. funds ohm HC49 package, or 4.00 -MHz only. R8- 7,500 -ohm ceramic resonator, see text

- whenever pin 13 of U8 is at a logic low. and hardware to create the call -pro- gated on and off, such as in a busy Because the four -bit code is latched gress tones. Under microcontroller signal pattern, the microcontroller involved. To at the falling edge of waveform pre- control, U8 can simulate a number of must occasionally get to pin 13 of U8, the RBO -RB3 the audio tones that are normally create the cadence heard in the ring sented bits can be immediately freed for use heard while using a phone. Some of and busy tones, the microcontroller to by the DTMF receiver or the LED dis- the sounds are composed of Iwo fre- must set pin 13 of U8 to a logic high latch. quencies mixed together; others are mute the audio during the silent peri- play simple single tones. Table 3 lists a few ods. Our task -based software pro- There are three dif- of the four bit codes that are sent to U8 gram is used to schedule those time Power Supplies. low-voltage, DC power sup- to create the call progress sounds. sensitive operations. ferent the design. Common three- 37 Because the tones may need to be The progress tones are generated plies in

www.americanradiohistory.comAmericanRadioHistory.Com ry, so either the 0.5 -amp (78Mxx) or l- TABLE -PROGRESS 3- CALL -SOUND CODES amp (78)x) type regulators can be used. Because Tone Frequency D3 D2 D1 DO they are series -pass- type regulators, they can run very Dial 350/440 o 0 0 0 warm while in operation. You must use Special 400/off 0 0 0 1 a heatsink on U5 to maintain a com- Alert 440 /off 0 0 1 0 fortable operating temperature. Ring 440/480 0 0 1 1 Busy The simulated phone -line talk -path 480/620 0 1 1 0 power ( "battery" voltage) is provided by an LM317 IC (U3), another popular terminal IC regulators are used to de- tapped, full -wave rectifier design that three -terminal regulator. Unlike the rive the required digital, analog, and begins with diodes D3 and D4. Ca- 78xx- series regulators, that device talk -path power. pacitor C8 is used as a bulk filter to the can provide an adjustable range of The digital logic and analog circuit- raw DC (about 16-20 volts DC) before voltages as selected by resistors R7 ry is powered by LM7805 (U5) and being applied to the IC regulators. and R8. The chosen resistor values set LM7812 (U4) fixed voltage regulators. Regulator U5 provides 5 volts DC for the output to about 29 volts DC. Al- Those popular devices provide excel- the digital logic and U4 provides 12 though most phone lines use a 48 -volt lent voltage regulation and have in- volts DC for the relay and analog cir- DC talk voltage, our 29 -volt DC supply ternal over -current and over- temper- cuitry. will work correctly with all standard ature protection. We only need a few hundred milli - telephone equipment. The power supply uses a center- amps of current to operate the circuit- The talk supply begins with rectifier To POWER BOARD

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EXT CTRL' Fig. 6. Use this parts -placement diagram when mounting components on the unit's main board.

www.americanradiohistory.comAmericanRadioHistory.Com Install and label S1 as MODE and S2 as BR1, the full -wave bridge, which con- TO RING on your enclosure's front panel. verts the incoming low- voltage AC to 117 VAC Again, connect them to the PC board unregulated DC (about 36 -volts DC). using 5- inch -long pieces of 22 -24 Capacitor C9 is used to bulk filter the AWG stranded wire. raw DC voltage before it is applied to Install modular jacks at the J1 and the regulator. J2 positions. Each jack's green wire is You may also notice that the reg- connected to the square pad on the ulator's ADS terminal is connected to board and the red wire is connected optoisolator U12. That optically iso- to the other pad. Cut off any extra lated switch is used to shut off the volt- wires that may be on the connector. age regulator during the CPC Install potentiometer R35 on the (calling -party control) pulse. When rear panel of your enclosure and la- enabled by the microcontroller, U12 bel it as DELAY. Connect the potentiom- reduces the talk voltage to about 1.2- eter to the appropriate points on the volts DC, which is low enough to simu- PC board using stranded wire. late the CPC condition. If after testing your finished project you find that the delay control works Construction. Although Ring -It! is a backwards, merely reverse the con- fun project to assemble, it certainly is CT nection to the potentiometer's wiper. notfor beginning electronics -kit build- TEE TEXT If installed correctly, the delay time ers. If you don't have experience with TO MAIN should increase as the control is CMOS IC's and PC -board assembly, BOARD moved clockwise. please obtain help before starting. If you find that you can not achieve We have provided PC foil patterns Fig. 7. The power board is set up for modified a 10 -90 second delay range, then for the main board (Figs. 2 and 3) and 117 -volt operation, but can be 220 -volt use by cutting traces and C24 or R35 are out of tolerance the power board (Figs. 4 and 5) so that for adding jumpers as described in text. (check them). Although the software you can etch your own boards if you has been designed to allow correct wish. You may find it more convenient operation over a wide range of com- to purchase a commercial -quality PC to static. They can be damaged ponent tolerances, it may be neces- board from the source listed in the through mis- handling! sary to try different components at Parts List. If you do purchase the Component XTAL1 can be either a U11, C24, or R35 to get the desired board, do not clean it before solder- quartz-type crystal as specified, or a range. ing; the boards available from the ceramic resonator. Delete capacitors The power transformers, T2 and T3, supplier have a special tin plate coat- C14 and C15 if using a ceramic reso- are split bobbin types with dual ing that prevents oxidation. nator with built -in capacitors. 50 /60Hz primaries and secondaries. The parts -placement diagrams for Use a socket to mount the micro - standard power transformers is the two boards are shown in Fig. 6 controller (U9). A special right -angle Using not recommended, especially at the (main board) and Fig. 7 (power IC socket (made by Vertisocket and T2 location. Such transformers are board). The AC transformer (T3) and available from Digi -Key Electronics, PO Box 677, available from sources such as Micro - fuse (F1) are installed on the power 701 Brooks Ave. South, tran, Magnetek/Triad, Signal Trans- board; the bulk of the remaining com- Thief River Falls, MN 56701 -0677; Tel. former, PREM Magnetics Inc., and ponents, including all of the digital cir- 800 - 344 -4539) is used at DISP1 to ver- cuitry, are installed on the main tically mount the seven segment LED others. to observe the orientation of board. Among other things, the two for proper viewing. Sockets should be Be sure the transformers. On T1, match the "P" board approach was used to pro- used for the other IC's, but are not and "S" references on the parts - mote safety. Always exercise caution absolutely required. Install two -pin placement diagram. It may be nec- when working near the power board's headers with shorting blocks at the essary to cut off the frame's mounting high voltages. JU1 and JU2 positions. tabs on some transformer designs. In- Use a 25 -47 -watt soldering -iron; Transistors Q3 and Q4 as well as the stall T2 and T3 so that the transformer's temperature -controlled irons set to three voltage -regulators (U3 -U5) pin 1 is in the square pad. 7000-800° work best. Do not use a sol- should be anchored to the PCB with The power board layout is already dering gun! Use only rosin -core solder 4 -40 x 1/a -inch machine screws and set for 117 -VAC operation. However, it with a 60/40 tin /lead content. nuts. Use a heatsink and thermal can be converted to 230 -VAC opera- Part substitutions are not recom- grease (heatsink compound) on U5, tion for use outside the U.S. For 230 - mended. Use the components shown the 7805 regulator. Please note that it's warm VAC operation perform the following in the Parts List and only substitute normal for that regulator to feel cuts and jumps: Cut the trace be- those that you know are exact re- during operation. tween the pads designated A and B in placements. For correct cycle -delay Install and label LEDI as CONNECT on Wire it to Fig. 7, cut the trace between the pads operation, do not substitute U11 with a your enclosure's front panel. designated c and D, and add a non -HCT type IC. the PC board using 5- inch -long wire. jumper between pads B and c. Use care in handling the IC's; they pieces of 22-24 AWG stranded (Continued on page 90) 39 are CMOS devices and are sensitive Be sure to observe proper polarity.

www.americanradiohistory.comAmericanRadioHistory.Com A DX Beam -Aimer Program

Here's a nifty program that allows you to enter latitude and longitude of two points, and calculates the true direction and true nautical distance between them.

BY FRED BLECHMAN K6UGT

Whether you are a ham -radio center of the Earth is a great circle. direction between major cities -but operator or a serious short- You can estimate the length of an not necessarily from where you are to wave listener, your antenna arc on a great circle by placing a where you want to go. With this pro- is one of the most important elements string between the origin and the des- gram, you can "start" and "stop" any- of your radio equipment, Further- tination on a globe, but the accuracy where! more, since most antennas are direc- is limited by the size of the globe. How- While hams and SWL's will benefit tional, for long- distance communica- ever, the DX Beam -Aimer Program the most from the program, it can also tion you need to "aim" your antenna that we'll present in this article is accu- be used for long- distance boating properìy. rate to a small fraction of 1 percent! It and aircraft flight planning. And, cl- This is not as simple as it sounds, can be used to determine the short- though the program is written in IBM since the Earth is a sphere and flat est distance and direction between PC GWBASIC, it has intentionally been maps are notoriously inaccurate. virtually any Iwo points on Earth, given designed so it will run on most micro- When I went through navigation the location of each. Many charts are computer BASIC interpreters with little courses as part of my flight training to available that give the distance and or no changes.

become a Naval Aviator, I became aware of the compromises made in

trying to reduce a spherical surface LATITUDE (the Earth) to a flat sheet of paper (a LINES map). It just can't be done with accuracy over long distances. If the angles are correct, then the distances are distorted, and vice -versa. Probably the most common map of the world, or large areas of the Earth, is a Mercator Projection, where all the latitude (horizontal) and longitude (vertical) lines are shown straight and perpendicular to each other. While this is easy to read, it is notoriously inaccurate for navigational purposes. Although the old expression that 'the shortest distance between two points is a straight line" is certainly true in spatial relations, it is totally false on most maps. In the case of a spherical object, which the Earth approximates, the shortest distance is along the surface LONGITUDE LINES the arc of "a great circle. " The inter- (MERIDIANS) section of the surface of the Earth with Fig. 1. Since the Earth is a sphere, all paths between points on its surface are really arcs a flat plane that passes through the with their origins at the Earth's center.

www.americanradiohistory.comAmericanRadioHistory.Com the "destination," then side D would LISTING 1 between * * * ** * ** * * * * * * * * * * * * * * * * * * * * ** be the great circle distance 100 REM ******************* * -Aimer" 110 REM * "DX Beam them, and angle G would be the di- 1993 K6UGT * Copyright Fred Blechman 120 REM (C) * * * ** * * * * * * * * ** * * * * * * * * * * * * ** ** from the 130 REM ******************* rection measured clockwise VARIABLES * DIM A(11): REM * SET ARRAY SIZE FOR 140 north. Side F would represent the an- 150 CLS : PRINT PRINT SURE KEYBOARD IS IN CAPS -LOCK MODE! ***":PRINT: 160 PRINT TAB(14) " * ** BE gle from Point A to the North Pole, side "GREAT CIRCLE DISTANCE AND DIRECTION" 170 PRINT TAB(2O) POINT A TO "TO DETERMINE THE SHORTEST DISTANCE FROM Point B to the North : PRINT TAB(1O) E from 180 PRINT THE" the angle B, AND THE DIRECTION FROM A TO B, ENTER 190 PRINT TAB(1O) "POINT I I would be the an- 200 PRINT UCA AND LONGITUDE Pole, and angle FROM I A MAP, GLOBEGORE ENCYCLOPEDIA." 210 PRINT TAB(1O) "THESE CAN BE FOUND them at the HAS ANGLE G AT POINT A, gular distance between 220 REM * SPHERICAL TRIANGLE OPPOSITE POINT B, 230 REM SIDE E OPPOSITE POINT A, SIDE F Pole, These are not important to use ANGLE I. 240 REM AND SIDE D OPPOSITE NORTH POLAR ;:INPUT "WHEN READY TO PROCEED, PRESS ENTER ";A$ but they are used in the 250 PRINT : PRINT TAB(1O) the program,

: PRINT ,, 260 CLS : PRINT PRINT as KEYBOARD IS IN CAPS -LOCK MODE! PRINT: solution of the spherical triangle, 270 PRINT TAB(14) " * ** BE SURE 280 INPUT "POINT A NAME ";A$ you'll see. 290 INPUT "POINT B NAME ";B$ 300 REM * TRIANGLE DIRECTION To give you a feel of the program's W)";P$" ;P$ OR WEST OF ";A$;: INPUT " (E OR 310 PRINT "IS ";B$;" EAST a screen print -out of a typ- REM * INPUT LOCATIONS * operation, OF " ;A$;: INPUT A(1) 330 PRINT : PRINT "LATITUDE ical program session is shown in Fig. 2. 340 INPUT "NORTH OR SOUTH (N OR S) ";J$ 350 PRINT "LONGITUDE OF ";A$ ;: INPUT A(2) It starts with some instructions, then 360 INPUT "EAST OR WEST (E OR W) ";K$ OF ";B$;: INPUT A(3) asked for the names of the 370 PRINT : PRINT "LATITUDE you're 380 INPUT "NORTH OR SOUTH (N OR S) ";L$ INPUT A(4) starting point (Point A) and destination 390 PRINT "LONGITUDE OF " ;B$ ;: 400 INPUT "EAST OR WEST (E OR W) " ;M$ (Point B), and their latitudes and long- 410 CLS : PRINT : PRINT ;" IS ";A(1); "DEGREES "; "lines" are parallel 420 PRINT : PRINT A$ itudes. Longitude 430 IF J$ = "N" THEN PRINT "NORTH "; north and south and pass- 440 IF J$ = "S" THEN PRINT "SOUTH "; ines going " 450 PRINT " AND " ;A(2)' "DEGREES ing through the poles. These are 460 IF K$ = "E" THEN PRINT "EAST " ' 470 IF K$ = "W" THEN PRINT "WEST" "great circles" used to specify angles 480 PRINT B$ ;" IS ";A(3); "DEGREES " ; England, 490 IF L$ = "N" THEN PRINT "NORTH "; east or west of Greenwich, THEN PRINT "SOUTH "; 500 IF L$ = "S" which is considered zero longitude. A 510 PRINT " AND ";A(4); "DEGREES " 520 IF M$ = "E" THEN PRINT "EAST " ' typical longitude, specified in deci- 530 IF M$ = "W" THEN PRINT "WEST" 540 PRINT B$ ;" IS "; mal degrees, might be "longitude THEN PRINT " WEST "; 550 IF P$ = "W" 115,35 E." By contrast, "latitude" lines 560 IF P$ = "E" THEN PRINT " EAST "; " ;A$ 570 PRINT " OF run east and west, parallel to the 580 REM * DETERMINE F & E IN DEGREES 590 F= 90 -A(1) equator, but, with the exception of the 600 IF J$ = "S" THEN F= F +2 *A(1) great circles. 610 E= 90 -A(3) equator, they are not 620 IF L$ = "S" THEN E= E +2 *A(3) They ore used to specify an angle 630 REM * DETERMINE NORTH POLAR ANGLE I * -A(2) 640 IF ((K$ = "W ") AND (M$ = "W ")) THEN I= A(4) north or south of the equator, such as 650 IF ((K$ = "E ") AND (M$ = "E ")) THEN I= A(4) -A(2) 660 IF I<0 THEN I = -I "latituae 37.5 N." +A(2) 670 IF ((K$ = "E ") AND (M$ = "W ")) THEN I= A(4) +A(2) You'II find that better maps and en- 680 IF ((K$ = "W ") AND (M$ = "E ")) THEN I= A(4) 690 IF I>18O THEN I =360 -I cyclopedias give locations in latitude 700 IF I<0 THEN I = -I ; ") IS " ¡F; "DEGREES." POLAR ANGLE TO POINT A ( ";A$ using degrees and 710 PRINT : PRINT "NORTH and longitude, ; ") IS " ;E; "DEGREES." 720 PRINT "NORTH POLAR ANGLE TO POINT B ( " ;B$ " "DEGREES." If or encyclope- 730 PRINT "NORTH POLAR ANGLE BETWEEN POINTS IS ;I; minutes of arc. a map 740 REM * FIND ARC D IN DEGREES * use a globe, TO RADIANS * (fa is not handy, you can 750 J= .0174533: REM * CONVERTS FROM DEGREES + SIN E *SIN F *COS I 760 REM * COS D= COS E *COS F but you'll have to estimate the latitude 770 A(5)= COS (E *J) B 780 A(6)= COS (F *J) and longitude of Points A and from 790 A(7)= SIN (E *J)' the globe. 800 A(8)= SIN (F *J) the markings on 810 A(9)= COS (I *J) The program was designed to han- 820 D= (A(5) *A(6)) +(A(7) *A(8) *A(9)) FOR D FOLLOWS * 830 REM * ARCCOSINE CALCULATION dle inputs from either the northern or 840 Y =- ATN (D/ SQR (- D *D +1)) +1.5708 longitudes 850 REM * CONVERT RADIANS TO DEGREES southern hemisphere, and 860 Y =Y *57.2958:A(10) =Y If both the TO MILES * east or west of Greenwich. 870 REM * CONVERT ARC D DEGREES NAUTICAL MILES ON GREAT CIRCLE * 880 REM * 1 DEGREE =60 origin and the destination are on the ( " "DEGREES). A -B IS " ;Y *60; "NAUTICAL MILES ;A(1O); 890 PRINT : PRINT "DISTANCE MILE * the 900 REM * STATUTE MILE = 1.1515 NAUTICAL same longitude, you don't need 910 Y =Y *60 *1.1515 MILES." all, since longitude lines 920 PRINT "DISTANCE A -B IS " ;Y; "STATUTE program at DEGREES * 930 REM * DETERMINE G IN In such a case, one F) D *SIN F) * are great circles. 940 REM * COS G =(COS E -COS D *COS /(SIN 950 X =A(1O) degree of arc is equal to 60 nautical 960 A(11)= SIN (X *J) 970 G= (A(5)- (D *A(6))) /(A(11) *A(8)) miles, and the direction between G *G +1)) +1.5708 980 Y =- ATN (G/ SQR (- be 0 or 180 degrees. To use 990 Y =Y *57.2958 them must THEN Y =360 -Y 1000 IF P$ = "W" FROM NORTH." the program in this circumstance any- A -B IS " ;Y; "DEGREES CLOCKWISE 1010 PRINT : PRINT "DIRECTION 1020 END way, you may offset either the origin or destination longitude by around one will 1. That degree; the error that introduces Summary. The program North Pole, as shown in Fig. Program be insignificant. trigonometry to calcu- involves some fairly sophisticated uses spherical Although Earth coordinates are and angles of a math, but you needn't use any math late the lengths in degrees, minutes, skills to run the program. usually specified spherical triangle between the start- and and Point B and seconds of arc for longitude 41 ing point, the destination and the If Point A is the "origin"

www.americanradiohistory.comAmericanRadioHistory.Com TABLE 1- PROGRAM VARIABLES as Listing 1) was written in Microsoft Name Use GWBASIC for the IBM PC, which uses A(1) Point A latitude line numbers, and is essentially the A(2) Point A longitude same as IBM's BASICA. It will run fine in A(3) Point B latitude QuickBASIC or QBASIC, which do NOT A(4) Point B longitude need A(5) COS (E *J) line numbers. For our purposes, A(6) COS (F *J) the line numbers will make it easier to A(7) SIN (E *J) provide a line -by -line explanation of A(8) SIN (F *J) the program. Also, the varieties of A(9) COS (I *J) BASIC for A(10) Arc D; X older microcomputers A(11) SIN (D *J) (TRS -80, Commodore, Apple, etc.) use A$ Point A line numbers. B$ Point B The program is identified in lines D Point A to Point B arc; COSine D 100-130. Line 140 sets the size of the A E Point B to North Pole arc array to F Point A to North Pole arc eleven elements, A(1) to A(11). G These Point A to Point B angle measured clockwise from North; COSine G array elements will be used I Angle at North Pole between Point A and Point B later as a convenient place to hold J Degree -to- radian conversion factor variables in a simple and organized J$ Point A North /South flag fashion. Table 1 shows K$ Point A East/West flag how each of L$ Point B North /South flag the program variables is used.

M$ B I Point East/West flag Why did use arrays? I originally P$ Triangle direction East/West flag wrote this program for a computer Y Arc whose COSine is D; arc whose COSine is G that only had 26 single -letter X A(10) variables (A-Z), and it was convenient to use arrays as variables to keep some

sense of order. When I translated the TABLE TYPICAL 2- CIT program to the IBM I retained this ap- Direction proach so that the most spartan Approx. Approx. Nautical Statute from BASIC variants could still accept and Origin Destination Latitude Longitude Miles Miles North run the program. Hong Kong 22N 112E 6373.69 7339.3 311.83 Line 150 clears the screen and Tokyo 35N 140E 4759.13 5480.14 305.228 prints a blank screen line. Line 160 re- Sydney 35S 151E 6544.01 7535.43 240.073 minds you to Los place your keyboard in Zanzibar 8S Angeles 40E 8839.03 10178.1 42.2297 "caps -lock" mode, since some entries Miami 34N 26N 81W 1995 2297.24 93.6929 you make from the keyboard will not New York 118.5W 41N 74W 2135.83 2459.41 65.3378 be recognized by the program if in London 53N 0 4677.82 5386.56 32.7365 lower -case. Lines 170 -210 provide a Moscow 55N 37E 5312.82 6117.71 13.7649 program introduction, using the TAB Paris 45N 2E 5062.99 5830.03 37.7492 statement to format the screen print- Tokyo Sydney 35S 151E 4245.01 4888.13 170.47 ing. Lines 220 -240 contain remark 35N Miami 26N 81W 6462.68 7441.77 38.2432 statements that identify the spherical 140E Moscow 55N 37E 4118.69 4742.67 323.124 triangle angles and sides (as were Paris Hong Kong 22N 112E 5260,23 6057.15 60.6908 shown back in Fig. 1). 45N Zanzibar 8S 40E 3782.39 4355.42 136.842 Line 250 uses an INPUT 2E statement to New York 41N 74W 3217.27 3705.27 294.569 preserve the screen until you hit the Moscow New York 41N 74W 4051.52 4665.32 310.315 ENTER key (actually, any key will do) to 37E Sydney 35S 151E 7882.36 9076.54 94.2849 continue. Line 260 clears the screen and prints two blank screen lines. Line 270 reminds you again that you'll latitude, we will use decimal degrees times .01667 to get 0.7). To convert the need to be in caps -lock mode to only. That greatly simplifies the cal- decimal part of a degree to minutes, avoid lower -case character entries. culations without significantly affect- divide the decimal by .01667. Then lines 280-400 ask you for origin ing the accuracy. There are 60 When finished with its calculations, Point A and target Point B names and minutes in one degree of arc, and 60 the program summarizes your input locations in longitude and latitude. seconds in one minute of arc. For our information, then quickly gives you the Line 410 clears the screen and purposes, you can ignore seconds. angles of each point from the North prints two blank lines. Lines 420-570 You'll need to convert minutes of Pole, the nautical and statute miles summarize the information you've arc to decimal parts of a degree for between the two points, and the di- given the program about Points A and use in this program. One minute of arc rection in degrees, measured clock- B and their relationship. Now the com- equals .01667 degrees. For example, wise from the North Pole. puter goes to work performing the 16 degrees and 42 minutes would be calculations. 16.7 decimal degrees (you multiply 42 The Program. The program (shown (Continued on page 94)

www.americanradiohistory.comAmericanRadioHistory.Com BY RONALD A. REIS

kolis,e too lot 0O e Working with surface-mount technology is a lot easier than you might expect. Here are some SUlt tips for getting started with this innovativein method off pproject roJ building.

with traditional "insertion -mount tech- Looked inside the latest consum- picking up SMC's, let alone soldering nology' (IM1T) familiar to most hob - er electronic product lately? If them in place, looks hard enough. byists, which uses components with you have, then chances are the Also, this basic question might come leads that are inserted through the PC printed- circuit board and compo- to mind: Are SMC's even available to board. nents in your camcorder, pager, or CD experimenters? SMT approach results in signifi- player are not at all similar to whatyou Don't fret, and don't despair. Not The advantages, such as circuit have been building at your work- only is it possible to build electronic cant board size and weight reduction, en- bench. The leadless, discrete elec- projects using SMT, it can be accom- hancec circuit performance and re- tonic components in these products plished easily, quickly, and, most im- liability, easier manufacturing, consid- have shrunk to the size of rice grains; portantly, with many of the traditional cost reduction, and the the integrated circuits are often flea- tools and materials probably sitting erable every development of entirely new prod- size bugs with pins that are practically on your workbench. In add'tion, not be possible with- touching each other; and the month, electronics distributors are ex- ucts that would the use of SMT Consequently, it is printed- circuit board itself has no panding their surface -mount compo- out Your days estimated that by 1996, 70 to 80 per- holes, except, perhaps, for mounting nent offerings. So, read on. cent of all electronic assemblies will inside the case. Welcome to the fas- as a new kind of project builder might be surface mount. cinating, miniature world of surface - be just beginning. mount technology (SMT) -a world Can You Handle Them? The com- that sooner or later you, the elec- The What and Why of SMT. is mercial assembly of SMT circuit tronics experimenter, will have to en- Surface -mount technology a pack- the at- boards is a fully automated process. ter. aging revolution that involves " leadless" Surface -mount components were de- When looking at SMT -based con- tachment of tiny, essentially signed from the beginning to be sumer products, you might have won - components to pads on the printed a printed- circuit packaged in reel dispensers, put in cered how it is possible to build a or etched surface of - place by X -Y pick- and -place ma- project using such tiny, surface -mount board -hence the name, "surface That contrasts chines, and soldered onto the PC 45 components ( SMC's). At a glance, mount technology."

www.americanradiohistory.comAmericanRadioHistory.Com board using flow (wave) or reflow True, specially designed tools and methods. In a fully automated SMT as- equipment are available for those sembly line, no human hands ever tasks, and they should be used when- touch the components or the printed - ever possible. Nonetheless, much can circuit boards. be done with traditional tools, though Yet, throughout the life of an SMT they must be used in somewhat non- product, rework is offen required, and traditional ways. SOIL PLASTIC PACKAGE that does necessitate human inter- Fig. 3. The SOIL gull -wing, plastic vention. Skilled electronics techni- Teeny, Tiny, SMC's. Several dif- integrated- circuit package is so tiny, the cians often must manually remove or ferent types of SMC's are available. leads have only a 0.050 -inch space replace SMC's during initial assembly, There are discrete passive compo- between them. testing, troubleshooting, or repair. Fur- nents, such as resistors and capaci- thermore, project prototyping, the tors; discrete active components, sort of thing electronics experimen- such as diodes and transistors; inte- ters do all the time, is obviously done grated circuits; and a few SMC's that by hand, where one component at a do not fall into any of the other cate- time is positioned on PC the board gories, such as trimmers and LED's. and soldered into place. Not surprisingly, the leadless chip resistor is the most popular discrete passive surface -mount component. It is TRIMMER POTENTIOMETER available in standard values from 10 OR CAPACITOR ohms to 10 megohms, and in wattage PACKAGE Fig. 4. Trimmer potentiometers ratings as low as '/,o, and as high as 1/4, and A watt. trimmer capacitors come in this type of surface -mount package. The resistors are extremely tiny, the average size being just 0.080 inches indicate a decimal point. Therefore, long, 0.050 inches wide, and 0.050 2R2 specifies a 2.2 ohm resistor. inches tall. As shown in Fig. 1A, they The ceramic-chip capacitor is the come with external electrodes or ter- second most widely used discrete, minals. Since the resistors are so small, B passive, surface -mount component colored bands cannot be used to in- (see Fig. 1B). It comes in both non - dicate their value. A simple three -digit polarized and polarized versions. The system is used instead. The first two former range in value from 1 pF to 1µF; digits indicate the first two significant the latter (most often tantalums) are numbers of the resistance value; the available from 0.1 µF to 100 µE Volt- C third digit, the number of zeros. age ratings go as high as 1000 volts. Fig. 1. Here For example, a are three discrete passive code number 220 Surface -mount capacitors look a surface -mount components: indicates a (A) The 22 ohm resistor. A code lot like SMC resistors. They are the leadless -chip resistor, (B) the similar - number 221 would designate a 220 some size (some tantalums are larger) looking leadless -chip capacitor, and (C) ohm resistor. If the resistance value is and the terminals the MELF leadless- are almost identi- cylinder diode. less than 10 ohms, an "R" is used to cal. There is one major difference in appearance, however. BONDING In most cases, no value designation is EPDXY PASSIVATED WIRE printed on the COLLECTOR EPDXY BODY SEMICONDUCTOR capacitor -there is no room. Instead, LEAD BODY CHIP the thin BONDING cardboard backing that runs WIRE the length of a strip of packaged capacitors has a value printed on it about every inch, or so. Turning to discrete active SMC's, the two- terminal diode in an MELF (metal - electrode face) leadless cylinder is popular. The package, shown in Fig. 1C, is also known as an SOD, for small - outline diode, and is but '/,o of an inch EMITTER in diameter and 1/5 of an inch long. LEAD Low -power transistors come in PASSIVATED SOT -23 (small -outline transistor) pack- SEMICONDUCTOR BASE ages, as shown in Fig. 2. The devices CHIP are only 0.118 inches long, 0.05 inches SOT -23 SOT -89 wide, and 0.04 inches tall. Note the Fig. 2. The SOT-23 and SOT-89 are low- and high -power transistor packages, respectively. gull -wing lead configuration. With Note the difference in lead shape between these two discrete active SMC's. that shape it is much easier to solder

www.americanradiohistory.comAmericanRadioHistory.Com ter. A tweezers is mandatory for pick- LED CHIP, CONDUCTIVE MOLDED TRANSFER EPDXY DIE ATTACHED TO ing up tiny SMC's. It should have EPDXY PACKAGE CATHODE LEAD. BALL forceps -style tips. A vise is a must for BOND ON TOP PC while compo- CONTACT securing the board attached. Smooth - TRUNCATED CONE nents are being well. If you don't WITH SPHERICAL SILVER jaw type vises work LENS COLORED have a desk -top magnifying glass, STRIPE FOR you should consider purchasing one. CATHODE WEDGE LEAD At the very least, an inexpensive BOND IDENTIFICATION hand -held one should be used. ON box, ANODE As for the materials listed in the LEAD they are fairly self -explanatory. Solder should be 63/37 (tin /lead) or, better yet, silver- bearing solder at 62/36/2 REFLECTOR (tin /lead /silver). A diameter of 0.020 inches works well, but 0.015 inches is better. A noncorrosive liquid flux and BASE SILVER PLATED SQUARE drop dispenser are necessary. So is a COPPER ALLOY light -duty spray defluxer. A general - LEAD FRAME a wide variety purpose plastic cement, the kind 5. Subminiature surface -mount LED's, like this one, are useful in Fig. used for plastic, wood, or metal, is fine. of applications, due to their high reflection efficiency. When choosing solder wick, select a diameter of 0.030 inches. Finally, ordi- the leads, as you will discover shortly. nary clear tape, 1/2 an inch in diame- Transistors required to dissipate more ter, will work well. Any other materials power than the general -purpose that you might need are probably type are available in an SOT -89 pack- lying around your i souse. age, also shown in Fig. 2. integrated circuits Surface -mount Putting SMC's in Their Place. are available in a number of pack- There are three easy ways to hold ages with a variety of lead configura- SMC's down in preparation for solder- tions. The type most likely to be ing them permanently in place. You encountered by the electronics ex- can tape, stick, or tag them to the PC perimenter, however, is the small out- board. line integrated circuit (SOIL) shown in To temporarily hold an SMC in 3. Note, again, the gull -wing lead B Fig. place by taping, begin by simply configuration. While SOIC's look like grasping a short strip of clear tape miniature DIP's (traditional through - and "touching" it to the SMC, picking hole IC's), they are barely'/4 the size of up the latter. See Fig. 6A. You then their larger cousins. Furthermore, their tape the SMC onto its PC board pads. lead spacing is only 0.050 inches, half With the component held securely in that of the traditional DIP place by the tape, solder the exposed Many other electronic compo- C terminal(s) (Fig. 6B). Remove the tape, nents, in addition to the ones dis- Fig. 6. To hold an SMC in place by then solder the remaining terminal(s) cussed above, come in surface - taping, (A) begin by touching the tape to to their pads (Fig. 6C). configurations. While all can mount the SMC. (B) After taping the here, two not possibly be discussed component to the PC board, solder the deserve particular note. Trimmer po- exposed terminal(s). (C) Finally, remove tentiometers and trimmer capacitors the tape and then solder the remaining come in the type of package seen in terminal(s) to their pads. Fig. 4, and are quite common. Typical you will potentiometer values range from 100 Tools and Materials. Below, used to hold SMC's ohms to 2 megohms. Trimmer capaci- find three methods hand -soldering with tors are found in values from 1.4 pF to in place while wire. Since you will undoubted- 50 pF. solder with all three ap- Subminiature surface -mount LED's, ly be experimenting obtain all of the of the type shown in Fig. 5, are now proaches, you should listed in the Tools finding wide application in electronic tools and materials an SMC in place, circuits. Due to their high reflection and Materials box. Fig. 7. To tag solder the soldering iron of solder on a pad, place efficiency, the brightness of these For SMT work, create a pool watts and above it, and reheat the does not decrease with size. needs to be from 25 to 40 the component LED's the SMC can "sink" close to - have a tinned tip with a conical solder so Note, once more, the popular gull 47 or less in diame- the board surface. wing lead configuration. shape, Yid. of an inch

www.americanradiohistory.comAmericanRadioHistory.Com NOT ENOUGH TOO MUCH Remove the iron, allow the solder to SOLDER SOLDER cool again, and release the tweezers. Then, with the component held in place, solder the other terminals or pins in a traditional manner. GOOD SOLDER BAD SOLDER JOINT JOINTS The Solder Connection. Once an Fig. 8. Here are examples of good and bad solder joints. Use them as a guide when SMC is held down by one of the three soldering to make sure your connections are good ones. methods just described, it's time to solder the remaining terminals or leads SOT -23 Another way to hold an SMC to the in place. For SMC Iwo-terminal discrete circuit board in preparation SOLDERING IRON TIP for final SMC's, begin by cleaning the PC soldering is to glue it in place. A gen- board pads with steel wool. Next, eral- purpose glue (that comes in a using the tag method, because it will jar), such as the General Purpose Plas- give you quick practice in soldering, tic Cement, 10 -324, from GC Elec- solder one component terminal to its tronics, works well. pre- tinned pad as described earlier. When working with the glue, the Now solder the other terminal as you best way to dispense the material is would any traditional joint, but apply with a toothpick. Dip the pick into the just a dab of solder at the junction of liquid so it just touches the surface. the iron tip and component terminal. Then place a dot of glue on the PC See Fig. 8 for examples of good and board, being careful not to get any of bad solder joints. it on the copper pads. Gently press PADS To solder gull -wing leads on three - the component into place and let the and four -lead components, proceed glue dry for Fig. 9. Soldering gull -wing leads to a about 30 minutes. Be as above, only be sure to apply plenty careful not to apply too much glue; PC board is not impossible if the right solder and soldering iron tip are used. of liquid flux before you actually sol- remember, its purpose is only to se- Try a silver- bearing, 62/36/2 solder, with der. Doing so makes for a much more cure the SMC for soldering. The rule is: a 0.015 -inch diameter, and a conical effective solder connection. See Fig. "A little dab'lI do you." soldering iron tip, /io of an inch or less 9. Even though I often use the tape in diameter. Hand soldering DIP gull -wing SOIC's and stick methods just described, I to a circuit board is not difficult. Just prefer the tag soldering approach. It's follow these ten steps: easy, quick, and involves no Tools and Materials addi- 1. Make sure all pads are clean and For Attaching tional materials such as tape or adhe- SMC's ready for soldering. sives. All you need are tweezers, and You probably have most of these tools 2. Create a pool of solder on a corner the solder wire and soldering iron that on your workbench right now. pad in preparation for tag soldering. Tools 3. Hold the IC with a tweezers. SMC Distributors Soldering iron 4. Place the IC onto the copper pads. Tweezers Be sure to center the IC right -to -left as Vise well as -to- Here is a sampling of electronics dis- Magnifying glass top bottom. Hold the IC in tributors that carry a wide selection of place. SMC's. Materials 5. Apply the soldering iron Solder tip to the Digi -Key Corp. Liquid flux pre- tinned pad. Hold the iron in place 701 Brooks Ave. South Drop dispenser just long enough to flow the solder. Thief River Falls, MN 56701 -0677 Defluxer 6. Pivot the IC about the soldered pin Tel. 800 -344 -4539 Adhesive as necessary to again align all pins FAX: 218 -681 -3380 Solder wick with their respective pads. Electronic Goldmine Clear tape 7. Solder a second pin in the opposite PO. Box 5408 Scottsdale, AZ 85261 corner to the first. In doing so, don't Tel. 602 -451 -7454 you would use anyway. forget to apply a small amount of liq- FAX: 602- 451 -9495 First, apply a dab of liquid flux to uid flux. PC Jameco one board pad. Then create a 8. Bathe one line of pins with liquid 1355 Shoreway Road pool of solder on that pad. Allow the flux. Belmont, CA 94002 solder to solidify. 9. Solder the line of pins, one at a time. Tel. 800 -831 -4242 Next, with the SMC held in a Move quickly, yet adhere to the four FAX: 800- 237 -6948 tweezers, rest the component on its traditional soldering steps: apply Unicorn Electronics PC board pads and hold it in place. heat, apply solder, remove solder, 10010 Canoga Ave., Unit B -8 Using a soldering iron held in your and remove heat. Apply liquid flux to Chatsworth, CA 91311 other hand, reflow the solder, Tel. 818- 341 -8833 causing the opposite row of pins and solder as FAX: 818 -998 -7975 the component terminal to "sink" just described. close to the board surface. See Fig. 7. (Continued on page 91)

www.americanradiohistory.comAmericanRadioHistory.Com Build A WWV Receiver Get time, weather, frequency, and other information with this easy -to -build receiver.

BY BRIAN MCKEAN

via au- best reception. The voltage -stabilized Next to the crystal detector and and the hour, and continuously crystal oscillator will allow the receiver super- regenerative receivers, dio tones. WWV transmits 500 Hz on to maintain its calibration under vary- the direct -conversion receiver even minutes while WWVH transmits minutes. The 5 -, 10 -, ing conditions. is the simplest radio that any experi- 600 Hz on even Shortwave listeners will find the menter can build. Despite its being and 15 -MHz carriers operate at 10 kW through- geophysical alert messages useful in immune to spurious IF signals, which making them easily audible correlating radio propagation condi- plague super- heterodyne receivers, out the continental US. tions with solar activity and geomag- the direct- conversion receiver has Special voice announcements, netic field disturbances. The NIST been shunned in the past because of providing Global Positioning Satellite signals themselves provide direct in- component limitations that make first - status, Geophysical data, OMEGA formation on band conditions. Poor try receivers sensitive to 60 -Hz hum, navigation system status, and Pacific in otherwise good local - microphonics, and low- frequency and Atlantic storm warnings, are reception an reception time period is usually in- noise generated by active compo- broadcast in regu'Jr time slots. UTC to dicative of some geophysical distur- nents. But ever -evolving electronics UT1 conversion information is also bance, which will be noted in the alert technology has produced low- noise/ broadcast. message. The geophysical bulletins low -power amplifiers and mechan- Those stations also broadcast the (18 minutes after the hour for WWV ically stable components that prom- time of day, day of year, year, daylight and 45 minutes after the hour for ise to revive the direct -conversion saving's time status, leap second sta- WWVH) provide a daily summary of receiver. Low-power active elements tus, and UTC to UT1 conversion in a is past 24- hour's solar and geomag- allow battery operation, significantly digital format. The digital code -sec- netic -field activity with 3 -hour up- improving 60 -Hz suppression. transmitted at a rate of 1- bit-per dates of current geomagnetic field The WWV Receiver described in this ond on a 100 -Hz subcarrier that is article (which contains only one pulsed on and off, with the duration of conditions. value The solar -flux measurement is a tuned circuit) is comprised of readily the pulse representing the bit measure of the solar emission at 2800 available parts and its operating fre- "1" or "0" at the beginning of each MHz, and is related to the solar con- quency can be easily modified, al- second. The 100 -Hz subcarrier is typ- which is a measure of the total lowing you to monitor other signals. ically below the bandwidth provided stant, flux is re- by commercial shortwave receivers, solar flux at the Earth. Solar the upper atmo- WWV /WWVH Broadcasts. Radio so the pulses are not audible. sponsible for ionizing sphere and, as such, affects long - stations WWV (Fort Collins, CO) and The direct conversion receiver does distance high- frequency communi- WWVH (Kauai, HI), operated by the not have a high cutoff frequency on cations, which rely on ionosphere National Institute of Standards and the HPI; so the 100 -Hz pulses will be propagation modes. Technology (NIST), broadcast vast clearly audible on the direct -con- The "A" and "K" indices in the mes- amounts of information 24 hours a version receiver described in this arti- sage provide information on geo- day. The most obvious are the fre- cle. Although intended for digital magnetic -field activity. The "K" index is quency standards of the carrier (2.5, decoding, the low bit rate allows the with measured at 3 -hour intervals, and the 5, 10, 15, and 20 MHz), the 1- second BCD code to be decoded by ear "A" index is derived by taking the time interval, and the standard audio a little practice and a strong signal. by weighted average of the K index for a tones (440, 500, and 600 Hz), which The most useful data transmitted 24 hour period. From 0 UT to 2100 UT, modulate the carrier at regular inter- the NIST stations are the frequency the "A" index represents the previous vals. standards. Those carriers allow world- day's measure. Between 2100 and Voice announcements, broadcast wide frequency calibration to an ac- 2400 UT, the "A" index is estimated at one -minute intervals, give the time curacy of 1 ppm. The direct from the 7 "K" indices for that day. The of day based on a cesium clock and conversion receiver can serve in a "A" index is finally produced at 2400 UT expressed in "Coordinated Universal secondary capacity as a 10 -MHz, lo- lo- and remains unchanged until 2100 Time" (UTC). The radio stations are cal- frequency standard since the the following day. 49 identified by voice on the half hour cal oscillator must be zero beat for

www.americanradiohistory.comAmericanRadioHistory.Com ANTI AUDIO AMPLIFIER

+9V C16 RF AMPLIFIER 1+ SOURCE +9V MIXER 100 ^ C17 o .1 I R7 D1 B1 T1' 03 4700 1N34 C1 9V .0081 2N2222 H T2' C15 C10 C14 I .47 C19 .01 .01 .47 1/2 CA3240

R8 D2 C13 7 .01 100K = 1N3 EARTH/ /2 CA3240 /7177 CHASSIS T 444 4 GROUND R15 L R9 R11 - L - - - i ' 180K 10K S 270K I LOCAL 1M I OSCILLATOR +9V C20 METAL 680pF I SHIELD R10 R12 R14 C24 +9V R5 10K 10K 10K .001 1.5K

C22 D3 R13 C7 C21 1 1 N4729 4700 -+ ,a .01 47 T 3.6V ZENER Ea. I C23 02 T 1 2N2222 LM386

3 6 C8 5 J1 001 +I( 7 C9 R16 S 4 100 + C25 22K J 47 SPKR1 'SEE TEXT 8-320

Fig. 1. The single balanced -diode mixer used in the WWV Receiver includes a transformer to phase shift the RF input, while a pair of oppositely oriented diodes are used to phase shift the LO signal. The LO amplitude must be sufficient to forward bias the diodes.

U C o Ú wG) tti 7 5 INCHES a0 rnFig. 2. The author's prototype was assembled on a small printed- circuit board, measuring about 5 by 21/2 inches, and is shown here on a 1:1 scale. Geomagnetic -field activity is de- are selected based on the current "K" surements of peak X -ray emissions scribed in broad terms such as "quiet" and "A" indices. Solar activity de- from a flare event. 50 "unsettled," "minor storm," etc., which scribes the solar -flare activity by mea- Note: Further information regarding

www.americanradiohistory.comAmericanRadioHistory.Com ANTI EARTH/CHASSIS GROUND NIST broadcasts can be obtained by irW writing to: National Institute of Stan- dards and Technology, Radio Station County Road, Fort I C10 WWV, 2000 East D2 -R7- -R8-CI3_ Collins, CO 80524. Ask for NIST pub- -C15- -C18- p1 -C14- lication SP 432. --14-- IR11 C2U1 Circuit Detail. Figure 1 shows a sche- C8 I , of the WWV Receiver. R;09I i matic diagram I R5 I R2 I 11 Incoming RF is picked by the antenna I C21 1d7 (ANTI) and is coupled via an auto - -R13- C23 transformer to a grounded -base am- C22 C25 I4 plifier (Q3), before being applied to a I _4422 o1 Fil xTAL1 diode -mixer network that is corn - R17 Ç6 -C1-- C 3 I * prised of T2, D1, and, D2. Best mixer -C9- R6 R3 C2 cis C 4

performance is obtained when both I I secondary windings of T2 are identical, and D1 and D2 are matched. 'SEE TEXT oscillator SHIELDED -9V The output of the local 51 CABLE (LO) -a grounded -collector Colpitts oscillator (built around Q1) -is applied to emitter -follower/buffer Q2, SPKR1 which provides a low impedance drive signal for the mixer. Fig. 3. All the parts that comprise the WWV Receiver (except the battery, the power to the circuit The demodulated signal is capaci- switch, the antenna, and the headphone jack) are mounted directly board at the position shown tively coupled, through high -pass RC board. A metal shield (see text for details) is added to the local oscillator. networks to a pair of high gain op- to isolate the RF input section from the amp stages (U1 -a and U1 -b). The opamps provide a 50 -dB gain and incor- PARTS LIST FOR THE WWV RECEIVER porate low -pass filter capacitors in Amplifier U2 pro- the feedback path. mica or ceramic -disc SEMICONDUCTORS C5 -33 -pF vides a 20 -dB gain, thereby produc- C141 0.01 -gF, CA3240, HA3 -5152, C6, C7, CIO, C13, ing sufficient output drive for an 8- UI- HA7 -5222, or similar, dual op- ceramic -disc or 32 -ohm head- -µF, ceramic - ohm speaker, amp. integrated circuit C8, C18, C24 0.001 phones. U2 -LM386 low -voltage, audio - disc I6 Note that our receiver lacks a vol- power amplifier, integrated circuit C9, C16- 100 -RF, -WVDC, ume control and AGC circuitry. That QI-Q3-2N2222, 2N3904, or electrolytic or ceramic -disc simplifies the circuit without introduc- similar general -purpose NPN C12-47 -pF mica 0.47 -p.F, polystyrene, ing operational problems. The vol- silicon transistor C15, CI9 or mylar, or multilayer ceramic ume is controlled merely by adjusting Dl, D2 -1N34 germanium 07, C22, C23- O.1 -p.F, ceramic the length of the whip antenna. NTE112 Schottky, small -signal diode disc When driving 32 -ohm headphones, or ceramic disc 1N4729, or similar 3.6 -volt, 1- C20 680-pF mica the circuit consumes less than 25 mA; D3- watt Zener diode C21, C25- 47 -µF, 10 -WVDC, however, the current drain increases electrolytic to 40 mA when driving an 8 -ohm RESISTORS ADDITIONAL PARTS AND 5% units, speaker. That current drain is close to (All resistors are 1/4-watt, MATERIALS otherwise noted.) the limit of 9 -volt alkaline batteries, so unless ANTI -50- to 100 -cm telescoping RI, R4, R8- 100,000 -ohm headphone operation is preferred, antenna R2-4700-ohm -inch headphone especially under weak -signal condi- JI-Closed circuit'/ R3, R5, R6-1500 -ohm jack tions. R7, R13-470-ohm SPKR1 -8- to 32 -ohm, 0.5 -watt or R9, RIO, R12, R14- 10,000 -ohm less, speaker The WWV Receiver was Assembly. RI I- 270,000 -ohm S1 -SPST power switch a circuit assembled on printed- R15-180 ,000-ohm B1 -9 -volt alkaline, transistor-radio board, measuring about 5 by 21/2 R16-22 ,000-ohm battery the author's inches. A template of CAPACITORS TI, T2 -See text Fig. 2. 30 -pF crystal printed- circuit layout is shown in Cl, CI1 -20- to 100 -pF ceramic or XTALI -I0 -MHz, metal The parts -placement diagram for the mica trimmer (Mouser Printed- circuit materials, shield material author's layout is shown in Fig. 3. All the 242 -3610 -100 or equivalent) enclosure, metal headphone (32 ohm), parts except power switch S1, battery C2 -15 -pF mica or ceramic -disc (see text), ceramic -disc battery holder and connector, wire, B1, speaker SPKR1, and antenna ANTI C3- 360 -pF mica or C4-56 -pF mica or ceramic -disc solder, hardware, etc. are located on the board. 51 The crystal can be any of a number

www.americanradiohistory.comAmericanRadioHistory.Com Component Notes. The crystal is used in its parallel (anti -resonant) mode in the Colpitts oscillator. Paral- lel -mode crystals are specified for a particular circuit load- capaci- tance -usually 20 to 40 pF -for the 101/2T crystal to oscillate on frequency. Ca- pacitors Cl and C2 provide series Ì coupling to reduce the relatively large load capacitance of Q1 and

271/2 T d

} 21/2T

10.5cm

ANT GND B A' Fig. 4. Transformer TI is a home -made unit comprised of 40 closely wound turns of AWG enameled #26 wire on a 1/4-inch diameter air -core form, with taps at 21/2 and 101/2 turns from each end; after each tap, the winding continues in the same direction. of physical sizes (note that the board amplifier (Q3), as shown in Fig. 3. Sol- layout is designed to accommodate der the shield to the ground trace the most common crystal -package using short segments of stiff wire as sizes; the HC -49 HC To and -33). mini- supports. Once all of the board - mize microphonics -the generation mounted components have been in- B BC of an electrical noise signal by me- stalled, connect the off -board corn - C chanical motion (vibration) of parts ponents to the printed- circuit board Fig. within a device-after soldering XTAL1 though short lengths of hook -up wire. 5. Construction details for T2 (the mixer transformer) in place, secure it to the board with Mount the whip antenna on the are shown here. The diagram in A is a schematic RN or similar silicone cement. proposed case for the unit; if the an- representation of the unit once Tuning capacitors Cl and C11 tenna that you choose for your unit completed; B illustrates how the three should be installed with the tuning has a pivoting base, the unit can be lengths of wire are wound as a set on the screw connected to ground to allow mounted in just about any convenient bobbin; and C shows how the bobbin is use of a metal tuning tool. The holes location on the enclosure using a low connected to the pinned base. for T1 are arranged for use with a '/c- capacitance mounting method; or inch diameter, plastic coil form with a you can connect the antenna (ver- allow tuning the crystal frequency. The molded base of the type commonly tically mounted) directly to the board. trimmer range specified for Cl should found in older TV sets. The holes for T2 Many whip antennas are equipped satisfy most crystals. If you have no are sized for a common subminiature with a threaded base that can be se- information about your crystal, try it IF can. The leads of T2 should be cut as cured directly to the appropriate anyway. The oscillator's operation can short as possible and secured to mini- printed- circuit pads using a screw. If be checked by any number of meth- mize vibration. that arrangement is used, use a large ods, but the easiest way is to listen to Install a solderable -foil metal shield grommet to isolate the whip from the the receiver itself. (approximately 1 -inch high) between metal case where the antenna pass- The mixer diodes should be small - the local oscillator (Q1 and Q2) RF and es through. (Continued on page 93)

www.americanradiohistory.comAmericanRadioHistory.Com Build a Vacuum- Tube Audio Amplifier

Build this audio amplifier and hear the difference tubes make in sound, without making a big difference in your wallet.

BY LARRY LISLE

± radio or Vacuum tubes seem to have a That amplifier is flat within 1 dB from use with a battery- operated the out- glowing future in expensive, 20 to 20,000 Hz into a resistive load, tape player. At about 3 watts, for high -end audio equipment. and is deceptively uncomplicated put of the amp is adequate quiet How come? What makes people shell considering its performance. As ex- listening on a 15 -inch speaker, and is the out good money for amplifiers using plained below, the amplifier's design great for earphones. Of course, devices that most thought were ob- prevents hum and unwanted feed- tubes can be pushed slightly beyond solete years ago? back -two of the toughest problems the linear portion of their operating a kind of Those who like them say that tubes in the home construction of tube -au- curve (overdriven) to give sound better. They use words like dio systems. distortion that some "tube-philes" like; "mellow" and 'warm" to describe the Hum is minimized in Iwo ways: First, a more on that later. tube sound. On the other hand, there nickel -core input transformer, T1 The amplifier operates on a 120- are also those who don't like tube au- (available from Antique Electronic volt power supply. That is low for tubes reasons. dio, or say that there's no difference in Supply, 6221 S. Maple Avenue, Tempe, and was selected for safety the sound at all. AZ 85283, Tel. 602 -820 -5411; FAX: The "60" in the designation of the How do you tell if you like the sound 602 -820 -4643) is used. Then, any re- 60FX5's indicates the filament voltage. of tubes without making a big invest- maining hum can be further reduced Connecting the filaments of the two to be ment? Build the super -simple ampli- by balancing the two sides of the cir- tubes in series permits them fier described below and hear what cuit via R1, located in the cathode wired directly across the 120 -volt DC supply. The fila- tube sound is like at a reasonable circuit. output of the power oper- cost. That way, you can get some ex- Unwanted feedback is avoided be- ments of audio tubes should be perience working with tubes while cause the circuit is designed as a sin- ated with DC whenever possible. building a nice little amp you'll be gle -stage amplifier. The sensitivity of The 60FX5 is a sensitive, inexpensive proud to own. the 60FX5 vacuum tubes, V1 and V2, tube (currently selling for under $3) makes that possible. that works well in the circuit, but other Circuit Description. The circuit The amplifier can be driven to full tubes could also be used without audio changing the socket connections. If shown in Fig. 1 is the classic push -pull output with less than 3 volts of tube amplifier used for generations. input on the grids, making it ideal for you want to substitute tubes with 50- 53

www.americanradiohistory.comAmericanRadioHistory.Com volt filaments, the 50FK5, the 50EH5, in either the cathode or screen cir- Construction. The amplifier pro- and the very common 5005 are cuits. totype was built on a 24- by 10 -inch good choices. However, a resistor will The power supply, shown in Fig. 2, laminated board that is sold at home be needed in series with the filaments, uses two low- voltage transformers, T1 improvement centers for shelving. A and the values of resistors cathode R2 and T2, connected back -to -back, al- smaller board could be used, but the and R3 might have to be changed. though a conventional isolation trans- large one provides room for experi- Transformer T2 is a good quality, 10- former could be used instead. Bridge menting and for the input radio or watt, tube -type audio -output unit that rectifier BR1 rectifies the input AC, and tape player. is also available from Antique Elec- capacitor C1 filters the resultant DC. To wire the circuit, use insulated wire tronic Supply (as model PT- 1608). Its The filament voltage is taken from that and make connections with primary has an impedance of about 120 -volt point. Resistor R1 then drops fahnestock or similar clips; fasten the 8000 ohms, center tapped, and the that voltage, and capacitor C2 filters clips to the board with wood screws. secondary has taps for 4, 8, and 16 it further. The plate and screen volt- Mount R1 on a corner bracket so it is ohms. The 220 -ohm screen resistor, R4, ages are then taken from the resulting raised above the surface of the is used to drop the screen voltage to a 92 -volt output. For safety and for hum - board. That prevents you from coming little below the plate voltage. Bypass control reasons, ground the circuit as into contact with the exposed con- capacitors were not found necessary shown. nections when making adjustments. When connecting the tube sockets, it is easiest to wire them, screw them to the board, and then trim the wires to an appropriate length. As for the leads of T1 and T2, don't trim them too short-you might want to use the transformers in other projects. The audio output from T2 can either be wired to fahnestock clips, or connected to an audio jack, depending on the nature of your speaker's leads. INPUT OUTPUT The power -supply prototype was built on a separate 9- by 4 -inch pine board so it could be physically separated from the amplifier. That is a good practice in audio work because hum might be radiated by the magnetic fields of the transformers and

PARTS LIST FOR THE 'SEE TEXT 7 TUBE AMPLIFIER V1 V2 RESISTORS /\ /\ (All fixed resistors are 5% units) 4 3 -R1 -25 -ohm, 2-watt, potentiometer R2, R3-47 -ohm, 1/2-watt R4- 220 -ohm, 1 -watt +120VDC +92VDC FILAMENT PLATE/SCREEN ADDITIONAL PARTS AND MATERIALS Fig. I. Here is the schematic for the tube amplifier. Its single -stage design, which T1 -Tube interstage transformer, 1;1 eliminates unwanted feedback, was made possible by the sensitive 60FX5 vacuum tubes. to 1:3 turn ratio, Antique Electronic Supply PT-157 or equivalent +120VDC BR1 FILAMENT T2- Tube -type audio -output T1' T2' 4A 400 PIV transformer, Antique Electronic R1 Supply PT-1608 or equivalent (see 330g text) +92VDC VI V2-60FX5 vacuum tube PLATE/SCREEN 24- by 10-inch baseboard, corner bracket, knob for variable resistor, two 7 -pin miniature tube sockets, 'SEE TEXT fahnestock clips, audio -output jack (optional), speaker or headphones, Fig. 2. The power supply for the amplifier uses two low - voltage transformers alligator clips, screws, insulated connected back -to -back. The full -wave bridge rectifier, BRI, provides DC for the wire, solder, hardware, etc. filaments, plates, and screens.

www.americanradiohistory.comAmericanRadioHistory.Com hash (RF noise) might be given off by the rectifier. Like the amplifier, you can wire the power supply using insulated wire and fahnestock clips. A small terminal strip can be used to mount BR1. To prevent strain on T1 and T2, use a couple of cable clamps on the power cord. If you're new to tube voltages, be careful! Do not touch any part of the amplifier except the knob of 121 while the power supply is plugged in. After unplugging the amplifier, short the two positive- output fahnestock clips on the power supply to the negative clip to make sure the capacitors have discharged. If the amplifier and power supply are to be board from the amplifier. It's placed in regular service where This power- supply prototype was built on a separate as separate units to prevent unwanted others might come in contact with usually wise to build audio power supplies them, they should be enclosed. Ex- noise. posed high voltages are not the only would like to hear the difference, try get hot! danger present-tubes triode PARTS LIST FOR THE reconfiguring the amplifier for operation. To do that, disconnect the Checkout and Use. Double -check POWER SUPPLY screen of each tube from R4. Then, all wiring to make sure it is correct. -amp, 400 -PIV, full -wave connect the screen of each tube to its Then, make the following connections ßR1-4 bridge rectifier own plate at the appropriate between the amplifier and power - R1- 330 -ohm, 5 -watt, 10% resistor fahnestock clip. The output and distor- supply using insulated wires that have Cl, C2- 100 -p.F, 250 -WVDC, tion should be less in the triode mode. insulated alligator clips on both ends. capacitor electrolytic Try both modes to see which you like Begin with the power supply Ti, T2 -117 volt to 12.6 volt, 3 -amp, better. unplugged. Temporarily connect the power transformer The idea of pushing a tube slightly plate /screen lead clip from the ampli- PLI -3- conductor power cord and beyond the linear portion of its oper- fier to the filament clip on the power plug terminal ating curve was mentioned earlier. supply. Properly connect the negative 9- by 4 -inch pine board, authorities say that tubes sound ground lead to the power supply. strip, fahnestock clips, screws, Some cable clamps, insulated wire, best when slightly over -driven that Then, short the input of the amplifier solder, hardware, etc. way. That is easy enough to try, just turn with a piece of wire, and connect a up the volume! speaker to the output of T2. the The push -pull arrangement of the Plug in the power supply and wait a the amplifier input. Then, connect to tubes tends to cancel the even har- minute or so for the tubes to warm up. filament -lead clip on the amplifier supply. monics. You can put the harmonics If the tubes warm up at a slightly dif- the proper clip on the power the back in by disconnecting the plate of ferent rate, however, the hum level Plug in the power supply, adjust en- one tube; however, hum might in- might be too loud. To prevent that, volume control on the radio, and crease. balance the circuit by adjusting R1 for joy the music. There is no "tone" control on the minimum hum. Any distortion in the radio or tape on to amplifier, but you can cut the highs Aller the circuit is balanced, unplug player will, of course, be passed and thereby boost the bass by con- the power supply. Connect the ampli- the amplifier (though "tube-philes" necting a 0.1 -µF capacitor across the fier plate/screen lead clip to the prop- say tubes make it sound better!). Also, secondary of the input transformer. A er clip on the power supply. Then, plug you'll find some music played over - variable resistor can be placed in se- in the power supply and wait for the the -air has built -in distortion -es- ries with the capacitor to make the tubes to warm up again. When they pecially on "oldies" stations. Sound that effect adjustable. do, the hum should be inaudible or quality is also affected by sources will sound You can sometimes cause subtle nearly so. If it isn't, try moving the use bass boost, as they variations in amp and speaker perfor- power supply away from the amplifier "bassier" through the amplifier. So making mance by connecting a small resistor or change the physical orientation of consider the above when that between the output transformer and the two circuits. evaluations in the experiments the speaker system. Also, resistors can Unplug the power supply and re- follow. be used to experiment with the vari- move the short from the input of the long ous forms of negative feedback. The amplifier. Connect a battery - Some Experiments. There's open construction of the amplifier powered radio or tape player with an been a debate in tube -audio circles If you makes it easy to try them all. 55 audio cable from its earphone jack to about pentodes vs. triodes.

www.americanradiohistory.comAmericanRadioHistory.Com Popular ANNUAL INDEX Electronics® 1994 Volume 11 The Magazine for the Electronics Activist! © Gernsback Publications, Inc.

Abbreviations: (AR)Antique Radio, (C)Construction, (CB)Computer Bits, (CC)Circuit Circus, (D)Department, (DX)DX Listening, (ED)Editorial, (HOR)Hands -On Reports, (HR)Ham Radio, (LTR)Letter, (MW)Multimedia Watch (PTR)Product Test Report, (SS)Scanner Scene, (TT)Think Tank

300 Interactive Multiple er, Panasonic Audio -Technica MMS557 FZ -1 REAL (Scaduto & O'Brian)(G) Bogen Communications Friday Personal Office Jun 49 Multimedia Speakers (Scaduto & O'Brian)(G) Aug 55 Receptionist Bose (Scaduto & O'Brian)(G) Jun 54 3D0 Software Roundup ( Scaduto & O'Brian)(G) Jun 50 Acoustic Wave Receiver/Alarm Clock (Scaduto BookMaker ClickBook ( Holtzman)(CB) Aug 76 555 Astable Roundup (Rakes)(CC) Jan 72 & O'Brian) (G) Feb 47 Design Acoustics PS-24 Shielded Bose Acoustic Wave Receiver /Alarm A AV Speakers (Scaduto & O'Brian)(G) Feb 50 Clock (Scaduto & O'Brian)(G) Feb 4' Design Your Own Loudspeakers (Hoffman)(C) Feb 40 Broadcasters SWL's Love to Hate, ABC's of Fisher Studio 24 CD Management The (Jensen)(DX) Mar 84 PDA's, The (Scaduto & O'Brian)(G) Mar 51 System (Scaduto & O'Brian)(G) Jan 49 Brother P-Touch PC Printers, The (Thurber) Apr 43 JVC JX -S700 AN Labeling Selector (Scaduto & O'Brian)(G) System (Scaduto & O'Brian)(G) Oct AC or DC? (Rybak) Sep 42,(LET)Nov 4 Jul 56 6' McIntosh Laboratories MC7100 Build A/An/The/This (See AC -Noise Construction) Detector ( Rakes)(CC) Oct 82 Power Amplifier (Feldman)(PTR) Jul 20 Build Your Own Text Editor (Holtzman)(CB) Apr 76 Accessories for Radio Listening (Thurber) Feb 68 Onkyo TX- SV717PRO AN Receiver Building Stable RF Oscillators (Carr) Accumat Sound Barrier, Schosche (Scaduto & O'Brian)(G) Feb 48 Nov 44 Schosche Industries Industries (Scaduto & O'Bnan)(G) Accumat Sound Barrier Bumps Along the Road (Laron)(ED) Jun Apr 58 and Damping Material Add -on LED Circuit (Rakes) (CC) Buying Used Test Equipment (Fonte) Jun Jan 72 (Scaduto & O'Brian)(G) Apr 58 6' Addresses and Questions ( Yacono)(TT) May 26 Sharp Model MD -D10 MiniDisc Player (Feldman)(PTR) Age of Information, The (Laron)(ED) Feb Aug 21 2 Sonance S3500 In- Wall AirConditioner Monito for Your C Car, Loudspeakers (Scaduto & O'Brian)(G) Oct 65 Build An (Caristi)(C) Aug 43 Sony MDS -101 MiniDisc Calculations, Thermal Alarm Circuit ( Rakes)(CC) Jun 76 Recorder (Feldman)(PTR) Apr 22 (Olivieri) Dec 56 Sony MZ -RS MiniDisc Walkman Call Blocker, Build the Alarm-Clock Adapter (Yacono)(TT) Sep 24 (Weeder)(C) Jun 31 Player Recorder(Scaduto & O'Brian)(G) All About Aug 47 Camcorder Team Monitor and Bass Subwoofer Speakers, Sharp ViewCam Crash Protection (Siuru) Nov VL -E3OU Camcorder with LCD 57 Rock Solid Sounds (Scaduto & O'Brian)(G) Nov 20 Viewfinder (Scaduto Nìghtvision Scopes (Rakes)(C) Apr 33 Technics & O'Brian)(G) Apr 5!!. SC -CH555 Mini Component Sony Handycam Snap! Piezoelectric Elements (Singmin) Mar 69 Stereo System (Feldman)(PTR) CCD -SC4 Radio Control Jun 21 (Scaduto & O'Brian)(G) (Spivak) Aug 39 Universal Noise -Reduction System, Apr 5E Transistors: FET's (Young) Can You Pass This FCC May 71 The (Panosh)(C) Jul 31 Exam? Feb 63 All -Band Delta-Loop Antenna. An ( Yamaha RX -V870 Stereo Car-Audio Supply ( Yacono)(TT) Carr)(HR 1 Aug 86 Dec 3E Receiver (Feldman)(PTR) Mar 22 AM FM Radio Kit, Elenco Electronics (HOR) Nov 24 Car-Battery Minder (Yacono)(TT) Jul 25 Audio- Technìca MMS557 Multimedia American Technology FM Sounds Miniature Car Security System, Build a Speakers (Scaduto d O'Brian)(G) Aug FM Radio (Scaduto & O'Brian)(G) Oct 71 55 Multi- Function (Caristi)(C) Oct 47 AudioAccess MRX Multi -Room Analog First - Response Monitor (Rakes)(CC) Apr 78 Casino, Electronic, Build This Controller (Scaduto & O'Brian)(G) 58 Analog -to- Digital Sep (Kirschenbaum)(C) Mar Converter for Your PC, AudioSource 4: A Low -Cost (Sanpitak)(C) Model SS Three ll Casio Apr 47 Surround Sound Processor (Feldman)(PTR) Jan 18 CMD -408 Wrist Controller Watch AND Gate Cut -Ott ( Yacono)(TT) Jul 25 Automotive (Scaduto & O'Brian)(G) Aug 52 Anemometer, Build a (Sìmcox)(C) Jan 37 All About Crash Protection (Siuru) Nov 57 Zoomer (Scaduto & O'Brian)(G) Mar 5- Antenna Build a/an CD -ROM, Step Up to (Spiwak) Feb All -Band Delta -Loop Antenna, An (Carr)(HR) Aug Air-Conditioner Monitor for Your 3- 86 Channel- Output Funny Little Antenna, A(Carr)(HR) Dec 80 Car (Caristi)(C) Aug 43 Display (Yacono)(TT) Jan 22 Topics ( Low -Cost Carr)(HR) Jul 86 Motorcycle Alarm (Kasper)(C) Feb 37 Chirping Security Add-On ( Yacono)(TT) Aug 2E Wire Antennas ( Carr)(HR) Multi- Function Car Security Jun 84 Christmas Stocking Stutter (Saxon)(SS) Dec 82 ANTIQUE RADIO (Eltis)(D) System (Caristi)(C) Oct 47 Jan 67,Feb 73,Mar 75 Electrical- Christmas Tree, Build Apr 74,May 75,Jun 71,Ju173,Aug System Analyzer for Your 73 Car (Caristi)(C) the "LED -Tric" (Panosh)(C) Dec Sep 21,Oct 22,Nov 68,Dec Mar 66 3 66 More Muscle and Vehicle Projects CIRCUIT Baby Boomer from Britain, A Oct ( Yacono)(TT) Jul 25 CIRCUS (D)(Rakes) Jan 72,Feb 80 22 Navigation Systems Mainstream Crystal Set Lore Jan Go (Siuru) Oct 75 Mar 83,Apr 7E 67 Police Cars Go High -Tech (Siuru) Finng Up the Tel -Ohmike TO-4 Dec Aug 59 May 79,Jun 76,Ju1 81,Aug 7E 66 Smart Vehicles are Here, Getting Started on the NBS Crystal The (Siuru) Jan 41 Sep 81,Oct 82,Nov 74,Dec 7'<, Set May 75 555 Mailbag Time! 21 Auto Auto Lamps ( Yacono)(TT) Astable Roundup Jan 72 Sep Jul 25 Fluid Detectors Mother of All Radio Museums, The Mar 75 A/V Jun 7E NBS Crystal Set, The Game Circuits Se 81 Apr 74 Circuits ( Yacono)(TT) Dec 30 NBS Post Scripts Inductive Transmitters Aug 76 Aug 3 Receiver, Onkyo TX-SV717PRO Your Putting Together the NBS Light Fire Jul 81 Set Jun 71 (Scaduto & O'Brian)(G) Feb 48 Making Resurrecting a Capacitor Analyzer Waves Nov 74 Nov 68 Selector, JVC JX -S700 (Scaduto & O'Brian)(G) Jul 56 Monitor /Detector Testing the NBS Set Speakers, Circuits Oct 82 Jul 73 Shielded, Design Acoustics Oscillator and Bridge Trip to Mecca, A Feb 73 PS -24 (Scaduto Circuits Mar 82 & O'Brian)(G) Feb 50 Plenty of Oscillators Antique Wireless Association Feb BC Some Assorted Circuits May 70 Museum ( Ellis)(AR) Mar 75 Take the Speed Test Apr 76 Apple Newton (Scaduto & O'Brian)(G) Mar 51 B Ultrasonic Circuits Dec 72 Arc Igniter ( Rakes)(CC) Jul 81 ClarisWorks for Windows ( Holtzman)(CB) Mar 8C Astable Multivibrator ( Rakes)(CC) Jan 72 B + K Precision Model 1686 Clock, Digital, Build a (Spiwak)(C) Jul61 DC Power Supply (HOR) 17 ATI Graphics Pro Turbo ( Holtzman)(CB) Nov 72 Jan Closed Caption Decoder, International Baby Boomer Computers AT &T E0 Personal Communicator from Britain, A (Ellis)(AR) Oct 22 (Scaduto & O'Brian)(G) Jun 5E (Scaduto & O'Brian))G) Mar 62 Barometer, Build a Portable (Caristi)(C) Jan 31 Code -Practice Oscillator (Rakes)(CC) Jun 7E Audible Voltmeter ( Rakes)(CC) May 79 Basic Ultrasonic Generator ( Rakes)(CC) Dec 72 Colorizing Movies -Much Ado About Nothing (Steckler)(ED) Audio Battery Amp -Hour Meter (Caristi)(C) Nov 51 Mar 2 Computer (See Accessones for Radio Beginners Course and Motion -Detecting Also Computer Bits, Listening (Thurber) Feb 68 Multimedia Watch) American Technology FM Sounds Miniature Alarms, A ( Yacono)(TT) Aug 24 Design Your Own FM Radio (Scaduto & O'Brian)(G) Loudspeakers (Hálman)(C) Feb 4C Oct 71 BellSouth Simon (Scaduto & O'Brian)(G) Mar 51 Elenco AudioAccess MRX Multi -Room Computer Interface Trainer (HOR) Jul 18 Beyond Ohm's Law (Coxwell) Going Online with Your Controller (Scaduto & O'Brian)(G) Sep May 66 PC (Thurber) Jun 37 58 Honeywell Mouse (HOR) AudioSource Model SS Three/II "Binocular" Coil Forms, Using (Carr) Apr 67 Apr 17 Surround Processor Inforite MP100 Writing Pad Sound (Feldman)(PTR) Jan 18 Bipolar Outputs ( Yacono)(TT) Jan 22 (Scaduto & O'Brian)(G) Apr 60

www.americanradiohistory.comAmericanRadioHistory.Com Firing Up the Tel -Ohmike TO-4 (Ellis)(AR) Dec 66 Low-Cost Analog -to- Digital Converter Digital for Your PC, A (Sanpitak)(C) Apr 47 Analog First -Response Monitor ( Rakes)(CC) Apr 78 Fisher Studio 24 CD Management Jan 49 Media Vision Memphis Multimedia Upgrade Capacitance Meter Auto -Ranging, System (Scaduto & O'Bnan)(G) Nov 62 81 Kit (HOR) May 22 Build an (Bolles)(C) Flash Circuit ( Rakes)(CC) Jul MicroCode Engineering CircuitMaker (HOR) Mar 16 Clock, Build a (Spiwak)(C) Jul 61 76 Fluid Detectors ( Rakes)(CC) Jun Nikon Coolscan 35 -mm Slide Combination Lock, Build A (Stephens)(C) Jul 70 FM Radio, Scanner (Scaduto & O'Brian)(G) Feb 45 First -Response Monitor ( Rakes)(CC) Apr 78 FM Sounds Miniature & O'Brian)(G) Oct 71 Tandy Sensation! Multimedia Video Mixer, Videonics MX -1 American Technology (Scaduto Personal Computer (Scaduto & O'Brian)(G) Jul 49 (Scaduto & O'Brian)(G) Oct 63 Fox FoXapper TV :Cable Remote & O'Brian)(G) Feb 53 COMPUTER BITS (D)(Holtzman) Jan 70,Feb 75, Diode Matching Circuit ( Rakes)(CC) Oct 82 Control (Scaduto Mar 80,Apr 76 Directional Discontinuity Ring Frequency Counter, Build a Nov 33 May 77,Jun 74,Jul 76,Aug 76 Radiator Antenna (Carr)(HR) Dec 80 50 -MHz (Weeder)(C) 77,Nov 72, Dec 70 Sep 76,0ct Feb 24 Friday Personal /Office Receptionist, Apr 76 Displays and Discrepancies ( Yacono)(TT) Build Your Own Test Editor Bogen Communications for Windows Mar 80 Distinctive Ring Switch, Build This (Layne)(C) May 33 ClarisWorks & O'Brian)(G) Jun 54 Feb 75 (Scaduto Crosstalk for Windows Do- It- Yourself Custom Installation 76 76 FrontRunner (Holtzman)(CB) Sep FrontRunner Sep (Scaduto & O'Brian)(G) Sep 56 Oct 77 May 2 IdeaFisher May 37 Fun and Games (Laron)(ED) It Documentation (Cunkelman) It May Not Be Sexy -But Funny Little Antenna, A (Carr)(HR) Dec 80 Sure is SCSI Jun 74 Door Ajar Unit ( Yacono)(TT) Sep 24 Just a Click Away May 77 Double Balanced Mixers, Using (Carr)(HR( Oct 87 Just for Kids -Not! Dec 70 ( Rakes)(CC) Jan 72 Odds and Ends Aug 76 Dual -tone Generator Shred Your Manuals! Jan 70 DX LISTENING (Jensen)(D) Jan 76,Feb 82,Mar 84, Va Va Va Video Nov 72 Apr 84,MMay 84,Jun 82,Ju1 84,Aug 84 G Word 6.0 for Windows Jul 76 Sep 84,Oct 85,Nov 80,Dec 76 SWL's Love to Hate, The Mar 84 Sep 81 Computer Interface Trainer, Elenco (HOR) Jul 18 Broadcasters Game Circuits ( Rakes)(CC) DX on the Tropical Bands Oct 85 "Gate-Dip" Meter, Build a (Veronese)(C) Nov 37 CONSTRUCTION E C.S.S. Jan 76 All About Nightvision Scopes (Rakes) Apr 33 Maritime CW Disappearing Apr 84 Gemstar VCR Pluscc Control Tower Universal Build A/An/The/This Money Crunch, The! Aug 84 Remote Control (Scaduto & O'Brian)(G) Oct 69 Nov 80 50 -MHz Frequency Counter (Weeder! Nov 33 Radio Jamming in the 1990's George H. Heilmeier and the LCD (Rybak) Dec 36 84 125 -MHz Logic Probe (Yost) Feb 57 Radio St. Helena Day Sep 2 Getting a Backbone (Laron)(ED) Jan Air- Conditioner Monitor for Your Shortwave- Broadcast Finding May 84 Aug 43 Shortwave Broadcasting in Singapore Dec 76 Getting Started on the NBS Crystal Car (Caristi) May 75 Anemometer (Simcox( Jan 37 South -American SW Broadcasters Jun 82 Set (Ellis)(AR) Auto -Ranging Digital Capacitance Viennese DX Feb 82 GIZMO (Scaduto 8 O'Brian)(D) Jan 49,Feb 45,Mar 51 Meter (Bolles) Nov 62 Will Ireland Return to Shortwave? Jul 84 Apr 55,May 51,(LET)Jul 3,Jun 49,Ju1 49 Battery Amp -Hour Meter (Caristi) Nov 51 Aug 47,Sep 49,Oct 63,Nov 9,Dec 9 Call Blocker (Weeder) Jun 31 3D0 Software Roundup Jun 50 Digital Clock (Spiwak) Jul 61 ABC's of PDA's, The Mar 51 Digital Combination Lock (Stephens) Jul 70 E American Technology FM Sounds Distinctive Ring Switch (Layne) May 33 Miniature FM Radio Oct 71 Jan 76 Electronic Casino (Kirschenbaum) Mar 47 E. C.S. S. (Jensen)(DX) AT &T EO Personal Communicator Mar 62 55 Electronic Paint Shaker (Covington) Apr 70 Easy -to- Remember Frequencies (Saxon)(SS) Sep 88 Audio -Technica MMS557 Multimedia Speakers Aug Nov 37 Controller Sep 58 "Gate -Dip" Meter (Veronese) Jan 2,Feb 2,Mar 2, Apr 2 AudioAccess MRX Multi-Room Home (Taylor) Oct 31 EDITORIAL (Laron)(D) Friday Security System May 2,Jun 2,Jul 2,Aug 2 Bogen Communications Tree (Panosh) Dec 33 Jun 54 "LED -Tric" Christmas Sep 2,Oct 3,Nov 3,Dec 3 Personal Office Receptionist Low-Cost Motorcycle Alarm (Kasper) Feb 37 Acoustic Wave ReceiverAlarm Clock Feb 47 Age of Information, The Feb 2 Bose Low-Voltage Power Controller (Rehman) Dec 58 P PC Labeling System Oct 67 Along the Road Jun 2 Brother -Touch Micro Messenger (Edwards) Sep 31 Bumps Controller Watch Aug 53 Movies Ado Casio CMD -408 Wrist Motion Memory (Edwards) Aug 63 Colorizing -Much NutriBase Personal Nutrition About Nothing (Steckler) Mar 2 CyberSoft Multi- Function Car Security Manager Apr 61 Fun and Games May 2 System (Caristi) Oct 47 Design Acoustics PS -24 Shielded a Backbone Jan 2 Nine -Band Shortwave Receiver (Williams) Mar 33 Getting Feb 50 Holiday Gift, A Dec 3 AV Speakers One-Tube Radio Receiver (Lisle) Oct 62 Custom Installation Sep 56 for All Seasons, An Aug 2 Do -it- Yourself Packet -Radio Tuning Indicator (Pliler) Jul 68 Issue Home Sep 53 Matter of Security, A Oct 3 Elan Showcase Portable Barometer (Caristi) Jan 31 24 CD Management System Jan 49 Issue, A Jul 2 Fisher Studio Radio -Controlled Car (Sheets & Graf) Aug 31 Special TV /Cable Remote Control Feb 53 Test for Your Workbench Nov 3 Fox FoXapper Relative -Humidity Gauge (Caristi) Jan 62 Gear VCR Pluscc Control Tower Universal Watching Multimedia Apr 2 Gemstar Remote -Control Relay Station (Yacono) May 69 Control Oct 69 You Can't Please Everyone Sep 2 Remote SCA Adapter (McCormick) Jun 44 Gizmo's Holiday Gift Guide Dec 9 24 Scanner Silencer (Pliler) Sep 73 Education and Alarms ( Yacono)(TT) Sep Hitachi VT-S772A S -VHS VCR with VCR Pluscc Jul 52 52 Smart Charger (Caristi) Sep 64 Elan Showcase Home (Scaduto & O'Brian)(G) Sep 53 Hyton Products Phonedex Autodialing Card File Jan Solid -State Cooler (Spiwak) Apr 37 Inforite MP100 Writing Pad Apr 60 Electrical -System Analyzer Versatile Data Logger (Malone) Jul 35 International Computers Closed Caption for Your Car (Caristi)(C) Mar 66 "Z- Dice" (Edwards) Dec 46 Decoder Jun 58 Jul 56 Design Your Own Loudspeakers (Hoffman) Feb 40 Electronic JVC JX -S700 AV Selector for Casino, Build This Lil' Orbits ScanTrak 18 Golfball Finder Jan 55 Electrical- System Analyzer 47,(LET)Apr 3 Mar 66 (Kirschenbaum)(C) Mar Media Vision Pro Moive Spectrum Video Your Car (Caristi) 81 Coin Toss ( Rakes)(CC) Sep Jan 56 How to Split a Power Supply (Covington) Jun 47 Capture Card Circuit ( Rakes)(CC) Sep 81 Low -Cost Analog -to- Digital Converter Craps MindMaster TV Allowance Television ( Rakes)(CC) Sep 81 Jan 51 for Your PC, A (Sanpttak) Apr 47 One -Arm Bandit Time Monitor (Rakes)(CC) Sep 81 Time- Model- Rocket Launch Twenty -One MuitiLink The Stick Voice.'FaxModem Delayed Jan 54 Control, A (Becker) May 41 ELECTRONICS LIBRARY (D) Jan 6,Feh 6,Mar 6,Apr B Call Processor Noise -Reduction System, May 8,Jun 8,Jul B,Aug 10 Multiplex Technology Channel Plus 9020 Universal Sep 60 The (Panosh) Jul 31 Sep 8,Oct 10,Nov 88,Dec 84 Video Distribution System Nikon Coolscan 35-mm Slide Scanner Feb 45 Variable Frequency RF Electronics Technician's Day Apr 40 Oscillators (Carr) Oct 41 Noise Cancellation Technologies Electronics Workbench, Interactive Image NoiseBuster Headset Jun 53 Jun 18 Consumer Electronics Show Technologies (HOR) Onkyo TX- SV717PRO AV Receiver Feb 48 Summer 1994 (Scaduto & O'Brian) (G) Nov 9 ( Yacono)(TT) Nov 30 Palm Computing PalmConnect Connectivity Where's the Hype? Electroscope WCES 94: Software Apr 63 May 51 Elenco Electronics (Scaduto & O'Brian)(G) FZ-1 REAL 300 Interactive AM FM Radio Kit (HOR) Nov 24 Panasonic Cooler, Build a Solid -State (Spiwak)(C) Apr 37 Multiplayer Jun 49 Basic Electronics Components CD -ROM Telephone Directories Aug 51 Corel SCSI (Holtzman)(CB) Jun 74 (Yacono)(TT) Aug 24 ProPhone Course FX40 Home Facsimile Jun 56 Nov 57 Interface Trainer (HOR) Jul 18 Samsung Crash Protection, All About (Siuru) Computer Industries Accumat Sound MM -8000 Microprocessor Trainer (HOR) Sep 18 Schosche Crosstalk for Windows (Holtzman)(CB) Feb 75 Barrier and Damping Material Apr 58 SP -1 Soldering Practice Kit (HOR) Feb 18 Jan 67 Sharp Crystal Set Lore (Ellis)(AR) Mar 16 Engineering CircuitMaker. MicroCode (HOR) 0Z- 960011 Wizard Pen -Based Organizer Feb 51 Custom Installation, Do- It- Yourself Mar 57 EO Personal Communicator, PI -7000 Expert Pad (Scaduto & O'Brian)(G) Sep 56 55 AT &T (Scaduto & O'Brian)(G) Mar 62 ViewCam VL -E3OU with LCD Viewfinder Apr CyberMan at Your Command (Spìwak)(MW) Sep 4 Sonance S3500 In -Wall Loudspeakers Oct 65 Equipment and Chips ( Yacono)(TT) Apr 26 Nutrition Sony CyberSoft NutriBase Personal Response Apr 56 Apr 61 Expanded Digital First- Handycam Snap! CCD-SC4 Camcorder Manager (Scaduto & O'Brian)(G) Apr 78 Monitor ( Rakes)(CC) ICF- SW100S World -Band Radio Receiver Nov 18 Aug 47 Expert Pad. Sharp PI -7000 MZ -RS MiniDisc Walkman Player /'Recorder 1994, The Nov 9 (Scaduto & O'Brian)(G) Mar 57 Summer Consumer Electronics Show Exploring New Horizons (Saxon)(SS) Nov 86 Tandy D Sensation! Multimedia Personal Computer Jul 49 Z -PDA Zoomer Mar 59 Team Monitor and Bass Subwoofer Speakers, Darkness Monitor ( Rakes)(CC) Oct 82 F Rock Solid Sounds Nov 20 Versatile (Malone)(C) Jul 35 Data Logger, Build the 63 TMC M2000 Programmable 2 -Line FCC Exam, Can You Pass This? Feb Jul 55 DBM Oscillator ( Rakes)(CC) Feb 80 Intercom Speakerphone Jul 81 FET -Based Sparker Light Your Fire ( Rakes)(CC) MX -1 Digital Video Mixer Oct 63 Power Supply, B + K Precision Videonics DC Feb 80 Technology Voice Organizer Aug 56 Model 1686 (HOR) Jan 17 FET Oscillator ( Rakes)(CC) Voice Powered WCES 94: Where's the Hype? May 51 72 FET's: All About Transistors (Young) May 71 DC -to -DC Converter ( Rakes)(CC) Jan Mole-House Entertainment Systems Sep 49 69 A/V Filter Circuits, An Introduction to (Young) Aug Oct 82 Design Acoustics PS-24 Shielded Glitch Detector ( Rakes)(CC) Speakers (Scaduto & O'Brian)(G) Feb 50 Field -Strength Meter, IC Engineering Jun 37 Dec 24 Going Online with Your PC (Thurber) 57 Design Your Own Loudspeakers (Hoffman)(C) Feb 40 Digi -Field (HOR)

www.americanradiohistory.comAmericanRadioHistory.Com Golf- Stroke ( Yacono)(TT) Counter Jan 22 Issue for All Seasons, An ( Laron)(ED) Aug 2 Walkman Player /Recorder, Ground Zero: The Other End of the It May Not Be Sexy -But It Sure Sony MZ-RS (Scaduto & O'Brian)(G) Aug 47 Radio Spectrum (Thurber) Oct is 55 SCSI (Holtzman)(CB) Jun 74 Mitsubishi HS -U57 VCR (Feldman)(PTR) May 24 Guide to Better Soldering, A (Thurber) Sep 37 Mobile Extenders, A Look at ( Saxon)(SS) Jun 86 J Model Railroad Crossing Flasher ( Yacono)(TT) Oct 24 H JASC Paint Shop ( Holtzman)(CB) Aug 76 Track -Control Signal (Yacono)(TT) Oct 24 JP Software 4DOS 5.0 (Holtzman)(CB) Aug 76 Model - Rocket Launch Control, A Time- Delayed (Becker)(C) May 41 HAM RADIO (Carr)(D) Jan 84,Feb 84,Mar 86,Apr 88 Just a Click Away ( Holtzman)(CB) May 77 May 86,Jun 84,Ju186,Aug 86 Money Crunch, The! ( Jensen)(DX) Aug 84 Just for Kids-Not! ( Holtzman)(CB) Dec 70 Sep 87,Oct 7,Nov 84,Dec 80 Monitor/Detector Circuits ( Rakes)(CC) Oct 82 All -Band Delta -Loop Antenna, An Aug 86 JVC JX -S700 A/V Selector More Ham Miscellanea Antenna Topics Jul 86 (Scaduto & O'Brian)(G) Jul 56 (Carr)(HR) Apr 88 Funny Little Antenna, A Dec 80 More Muscle and Vehicle Mechanical Things for Builders Nov 84 Projects (Yacono)(TT) Jul 25 More Ham Miscellanea Apr 88 Mother of All Radio Museums, The (Ellis)(AR) Mar 75 Operating in the Low Bands Jan 84 K Motion Memory, Preamplifier Oscillations Sep 87 Build the (Edwards)(C) Aug 63 Radio and the Solar Eclipse Feb 84 Kit Building Motion-Detecting Alarms and Receiver Performance Today May 86 Elenco Electronics A Beginner's Course ( Yacono)(TT) Aug 24 Using Double Balanced Mixers Oct 87 AM FM Radio Kit (HOR) Nov 24 Motorcycle Alarm, Build a Want to Operate W1AW? (Carr)(DX) Mar 86 MM -8000 Microprocessor Trainer (HOR) Sep 18 Low-Cost (Kasper)(C) Feb 37 Wire Antennas Jun 84 LEGO for the 1990's: The Lego Dacia Multi -Room Controller, AudioAccess Hamming in the Fabulous Fifties (Thurber) Mar 41 Control Lab ( Spiwak) Jun 64 MRX ( Scaduto & O'Brian)(G) Sep 58 Robix Robot Construction Set, The (Spiwak) Jan 46 Handycam Snap! Camcorder, Sony MultiLink The Stick Voice/Fax/Modem CCD-SC4 (Scaduto The Word on Kits (Thurber) Jul 43 & O'Brian)(G) Apr 56 Call Processor (Scaduto & O'Brian)(G) Jan 54 Kodak Model PCD 5870 Photo HANDS -ON REPORT (D) Jan 17,Feb 18,Mar 16,Apr 17 CD Multimedia (See Also Multimedia Watch) Player (Feldman)(PTR) Feb 20 May 22,Jun 18,JuI 18,Aug 18 Personal Computer, Tandy Sensation! Sep 18,Oct 18,Nov 24,Dec 24 (Scaduto & O'Brian)(G) Jul 49 Et* K Precision Model 1686 DC Power Supply Jan 17 Speakers, Audio -Technica Elenco Electronics L MMS557 (Scaduto & O'Brian)(G) Aug 55 AM /FM Radio Kit Nov 24 Upgrade Kit, Media Vision Memphis Latching Motion Detector ( (HOR) May 22 Computer Interface Trainer Jul 18 Yacono)(TT) Aug 24 MULTIMEDIA WATCH (Spiwak)(D) Apr 4,May 4 MM -8000 Microprocessor Trainer Sep 18 LC Oscillator ( Rakes)(CC) Feb 80 SP-1 Soldering Practice Kit Jun 4,Jul 4,Aug 6 Feb 18 LCD, George H. Heilmeier and the (Rybak) Dec 36 Honeywell Mouse Apr 17 Sep 4,0cí 6,Nov 6,Dec 6 IC Engineering Digi -Field LED circuit ( Yacono)(TT) Jan 22 CyberMan at Your Command Sep 4 Let's Get Into Something Field -Strength Meter Dec 24 LED Flasher (Yacono)(TT) Feb 24 New! Apr 4 Interactive Image Technologies Mac and the PC Worlds are Similar, The Oct 6 LEGO for the 1990's: The Lego My PC Gets Terminated Electronics Workbench Jun 18 May 4 Dacta Control Lab (Spiwak) Jun 64 PC Expo, and More! Logisym V3.2 Logic Simulator Software Aug 18 Nov 6 Media Vision Memphis Multimedia Lets Get Into Something New! (Spiwak)(MW) Apr 4 Put Some "ReelMagic" in Your PC Aug 6 Research Upgrade Kit May 22 LETTERS (D) Jan 4,Feb 4,Mar 4,Apr on CD -ROM Jun 4 3 Sounding Off MicroCode Engineering CircuitMaker Mar 16 May 3,Jun 3,Jul 3,Aug 4 Dec 6 Virtual Reality By the Seat of Your Pants 4 OrCad Schematic Design Tools 386+ Oct 18 Sep 3,0ct 4,Nov 4,Dec 4 Jul Headlightsrrum- Signal Reminder (Yacono)(TT) Jun Light Multiplex Technology Channel Plus 9020 24 Video Distribution Beam Circuit ( System Heavy -Duty Transmitter ( Rakes)(CC) Jun 76 Rakes)(CC) Aug 78 ( Scaduto & Detector (Rakes (CC) Oct 82 O'Brian)(G) Sep 60 Heilmeier, G. H., and the LCD (Rybak) Dec 36 Timer ( Yacono)(TT) Feb 24 Muscle Wire and Auto Stuff ( Yacono)(TT) Jun 24 Hewlett- Packard DashBoard Your Fire ( Rakes)(CC) Jul 81 My PC Gets Terminated (Spiwak)(MW) May 4 ( Holtzman)(CB) May 77,Aug 76 Lightning and the Radio Listening High -Level Detector (Rakes)(CC) Jun 76 Post (Thurber) May 44 N High -Level Handles (Saxon)(SS) Jan 86 Lights On Circuit ( Yacono)(TT) Jul 25 High -power flasher add -on (Rakes)(CC) Lil' Orbits ScanTrak 18 Jan 72 Navigation Systems Go Mainstream (Slum) Oct 75 Golfball Finder (Scaduto & O'Brian)(G) High -Tech War on Crime, The (Siuru) Dec 51 Jan 55 NBS Crystal Set Lock, Digital Combination (Stephens)(C) History Jul 70 Getting Started on (Ellis)(AR) May 75 AC or DC? (Rybak) Sep 42 Logic Probe, Build a 125 -MHz (Yost)(C) Feb 57 Post Scripts (Ellis)(AR) Aug 73 George H. Heilmeier Putting Together and the LCD (Rybak) Dec 36 Logic Simulator Software, Logisym V3.2 the (Ellis)(AR) Jun 71 (HOR) Aug 18 Testing the Hitachi VT-S772A S -VHS VCR with (Ellis)(AR) Jul 73 Logisym V3.2 Logic Simulator Software (HOR) Aug 18 The (Ellis)(AR) VCR Plus + (Scaduto & O'Brian)(G) Jul 52 Apr 74 Look At Mobile Extenders, A (Saxon)(SS) Holiday Gift Guide, Jun 86 Neon -Light Driver (Yacono)(TT) Jan 22 Loudspeakers, Design Your Gizmo's (Scaduto & O'Brian)(G) Dec 9 Own (Hoffrnan)(C) Feb 40 NEW PRODUCTS (D) Jan 12,Feb 10, Mar 12,Apr 14 Low-Cost Analog -to- Digital Holiday Gift, A ( Laron)(ED) Dec 3 Converter May 14,Jun 12,Jul 12,Aug 15 Home Facsimile. Samsung FX40 for Your PC, A (Sanpitak)(C) Apr 47 Sep 12,0cí 16,Nov 90,Dec 86 (Scaduto & O'Brian)(G) Jun 56 Low-Level Detector ( Rakes)(CC) Jun 76 Nightvisìon Scopes, All About (Rakes)(C) Apr 33 Home Security System, Build a (Taylor)(C) Oct 31 Low -Pass Filter ( Rakes)(CC) Aug 78 Nikon Coolscan 35-mm Slide Scanner (Scaduto & O'Brian)(G) Honeywell Mouse (HOR) Apr 17 Low -Voltage Power Controller (Rehman)(C) Dec 58 Feb 45 Noise How to Split a Power Supply (Covington)(C) Jun 47 Cancellation Technologies NoiseBuster Headset (Scaduto & O'Brian)(G) Jun 53 HV Static Detector ( Rakes)(CC) Mar 82 M Noise -Reduction System, Hyton Products Phonedex Autodialing The Universal (Panosh)(C) Jul 31 Card File ( Scaduto & O'Brian)(G) Jan 52 Mac and the PC Worlds are Similar, Not -So- Private Security ( Saxon)(SS) The (Spiwak)(MW) Oct 6 Oct 89 NutriBase Personal Nutrition Manager, Mailbag Time! (Ellis)(AR) Sep 21 Cybersott ( Scaduto & O'Brian)(G) Apr 61 Making Waves ( Rakes)(CC) Nov 74 Maritime CW Disappearing (Jensen)(DX) Apr 84 Matter of Security, A (Laron)(ED) o IC -Based Ignitor ( Rakes)(CC) Jul 81 Oct 3 IC McIntosh Laboratories MC7100 Engineering Digi -Field Field- Strength Odds and Ends ( Holtzman)(CB) Aug 76 Meter (HOR) Dec 24 Power Amplifier (Feldman)(PTR) Jul 20 Ohm's Law, Beyond (Coxwell) May 66 IdeaFisher (Holtzman)(CB) Mechanical Things for Builders (Carr)(HR) Nov 84 Oct 77 On Displays (Yacono)(TT) Media Jan 22 Igniter ( Rakes)(CC) Vision Jul 81 Memphis One -Chip Alarm ( Yacono)(TT) Sep 24 Improved Multimedia Upgrade Kit (HOR) May 22 Pro Moive Spectrum Video Capture Card One -Chip Receiver ( Rakes)(CC) May 79 Sawtooth Generator ( Rakes)(CC) Nov 74 (Scaduto & O'Brian)(G) Jan 56 Ultrasonic Generator ( Rakes)(CC) Dec 72 One -Tube Radio Receiver, Build a (Lisle)(C) Oct 62 Meter Adapter ( Yacono)(TT) Nov 30 In -Wall Loudspeakers, Sonance Onkyo TX- SV717PRO AN Receiver Micro Messenger, ( S3500 (Scaduto & O'Brian)(G) Oct 65 Build the (Edwards)(C) Sep 31 Scaduto & O'Brian)(G) Feb 48 MicroCode Engineering Operating in the Low Inductive Transmitters ( Rakes)(CC) Aug 78 CircuitMaker (HOR) Mar 16 Bands (Carr)(HR) Jan 84 Microprocessor Trainer, Optoelectronics Infrared -Beam Alarm ( Yacono)(TT) Aug 24 Elenco MM-8000 (HOR) Sep 18 CD440 CTCSS Decoder (Saxon)(SS) Jun 86 Inforite MP100 Writing Pad Microsoft Bookshelf '94 OrCad Schematic (HOR) (Scaduto & O'Brian)(G) Apr 60 (Holtzman)(CB) Dec 70 Design Tools 386+ Oct 18 Creative Writer ( Holtzman)(CB) Dec Interactive Image Technologies 70 Oscillator and Bridge Circuits ( Rakes)(CC) Mar 82 Fine Artist ( Holtzman)(CB) Electronics Workbench (HOR) Dec 70 Oscillators, Plenty (Rakes)(CC) Jun 18 Word 6.0 for Windows ((Holtzman) CB) Jul 76 of Feb 80 Intercom /Speakerphone, TMC M200 Word Developers Kit ( Holtzman)(CB) Jul 76 Programmable 2 -Line ( Scaduto & O'Brian)(G) Jul 55 MindMaster TV Allowance Television P International Computers Closed Caption Time Monitor (Scaduto & O'Brian)(G) Jan 51 Decoder (Scaduto & O'Brian)(G) Jun 58 Mini Component Stereo System, Packet-Radio Tuning Indicator, Build a (Plller)(C) Jul 68 Introduction to Technics SC -CH555 (Feldman)(PTR) Jun 21 Paint Shaker, Build An Electronic (Covington)(C) Apr 70 Filter Circuits, An (Young) Aug 69 Mini-Megaphone ( Rakes)(CC) May 79 Palm Computing PalmConnect Reactance, An (Coxwelll( Sep 69 Connectivity MiniDiec Software Schematic Symbols, An (Young) Nov 46 (Scaduto & O'Brian)(G) Apr 63 Player, Sharp MD-D10 (Feldman)(PTR) Aug 21 Panasonic FZ -1 REAL 3DO Interactive Intuit Quicken for Windows ( Holtzman)(CB) Aug 76 Recorder, Sony MDS -101 (Feldman)(PTR) Apr 22 Multiplayer (Scaduto & O'Brian)(G) Jun 49

www.americanradiohistory.comAmericanRadioHistory.Com 79 Some Assorted Circuits (Rakes)(CC) May Morel Nov 6 Radio -Controlled Car, PC Expo, and (Spiwak)(MW) 1 Oct 24 Build A (Sheets & Graf)(C) Aug9 Some Hobby Circuits ( Yacono)(TT) PC Labeling System, Nov 30 Oct 67 Random House Unabridged Some Shop Circuits (Yacono)(TT) Brother P -Touch (Scaduto & O'Brian)(G) Aug 76 Dictionary (Holtzman)(CB) In -Wall Personal Digital Assistants Sonance S3500 to (Coxwell( Sep 69 (Scaduto & O'Brian)(G) Oct 65 ABC's of PDA's, The (Scaduto & O'Brian)(G) Mar 51 Reactance, An Introduction Loudspeakers 24 AT &T SO Personal Communicator Receiver/Motor Interface ( Yacono)(TT) Oct Sony (Scaduto & O'Brian)(G) Mar 62 May 86 Handycam Snap! CCD -SC4 Receiver Performance Today ( Carr)(HR) Apr 56 Palm Computing PalmConnect Connectivity Camcorder ( Scaduto & O'Brian)(G) Software (Scaduto & O'Brian)(G) Apr 63 Relative- Humidity Gauge. ICF- SW100S World -Band Radio Jan 62 Nov 18 Sharp PI -7000 Expert Pad Build a (Caristi)(C) Receiver (Scaduto & O'Brian)(G) Apr 22 (Scaduto & O'Brian)(G) Mar 57 Remote Control MDS -101 MiniDisc Recorder ( Feldman)(PTR) Tandy Z -PDA Zoomer (Scaduto & O'Brian)(G) Mar 59 FoXapper TV /Cable (Scaduto & O'Brian)(G) Feb 53 MZ -RS MiniDisc Walkman Player/Recorder Aug 78 Aug 47 76 Receiver ( Rakes)(CC) (Scaduto & O'Brian)(G) Pest Repeller ( Rakes)(CC) Jun Relay Station, Budd A (Yacono)(C) May Dec 6 Airwaves, The (Saxon)(SS) Apr 90 Aug 78 Sounding Off ( Spiwak)(MW) Phantom of the Transmitter ( Rakes)(CC) South -American SW Broadcasters (Jensen)(DX) Jun 82 Phar Lap Software FrontRunner (Holtzman)(CB) Sep 76 Jul 81 Repetitive Sparker ( Rakes)(CC) Jul 81 ( Rakes)(CC) Phonedex Autodialing Card File, Jun 4 Sparker Research on CD -ROM ( Spiwak)(MW) Jul 2 Hyton Products (Scaduto & O'Brian)(G) Jan 52 Special Issue. A (Laron)(ED) Resurrecting a Capacitor (Rakes)(CC) Jun 76 Photo CD Player, Kodak PCD 5870 Analyzer (Ellis)(AR) Nov 68 Squarewave Generator Feb 20 Feb 31 ( Feldman)(PTR) 40 Up to CD-ROM (Spiwak) RF Oscillators, Building Stable (Carr) Nov Step 74 Photography Triangle Generator ( Rakes)(CC) Nov Set, The ( Spiwak) Jan 46 Stepped Nikon Coolscan 35 -mm Slide Scanner Robix Robot Construction 46 Starter Cut-Off (Yacono)(TT) Jun 24 (Scaduto & O'Brian)(G) Feb 45 Robot Construction Set, Robix (Spiwak) Jan Photo CD Player, Kodak PCD 5870 Team Monitor and Bass Stereo Receiver, Yamaha Feb 20 Rock Solid Sounds Mar 22 ( Nov 20 RX -V870 ( Feldman)(PTR) Feldman)(PTR) Subwoofer Speakers ( Scaduto & O'Brian)(G) Screen Shots and Project Photography Stick. The, Voice/Fax/Modem Call Processor, Dec 62 Jan 54 Made Easy (Blechman) MultiLink ( Scaduto & O'Brian)(G) Mar 69 Piezoelectric Elements, All About (Singmin) Studio 24 CD Management System. Jan 49 PIN Diodes, Switching with (Carr) Dec 40 S Fisher (Scaduto & O'Brian)(G) Mar 26 1994, Pinouts and Tools ( Yacono)(TT) Summer Consumer Electronics Show Nov 9 Home The (Scaduto & O'Brian)(G) Plenty of Oscillators ( Rakes)(CC) Feb 80 Samsung FX40 Jun 56 Jul 88 72 Facsimile ( Scaduto & O'Brian)(G) Summer Sports and Games (Saxon)(SS) PLL Ultrasonic Generator ( Rakes)(CC) Dec with Toner-Cartridge (Yacono)(TT) Jul 25 High -Tech (Siuru) Aug 59 Save a Bundle Super Simple Car Alarm Police Cars Go Recycling (Blechman) Mar 71 Sep 24 Surround Sound Processor, AudioSource Poor Man's Alarm ( Yacono)(TT) Nov 74 Jan 18 Sawtooth Generator ( Rakes)(CC) Model SS Three /II ( Feldman)(PTR) Power Amplifier, McIntosh Laboratories Dec 40 Jul 20 SCA Adapter, Build an Switching with PIN Diodes (Carr) MC7100 (Feldman)(PTR) (McCormick)(C) Jun 44,(LET)Aug 4 Power Controller, Low Voltage, Jan 86,Feb 86 Dec 58 SCANNER SCENE (Saxon)(0) Build a (Rehman)(C) Mar 86,Apr 90,May 88 Power -Failure Monitor ( Rakes)(CC) Oct 82 Jun 86,Jui 88,Aug 88 Sep 88,Oct 89,Nov 86,Dec 82 Power Supply Dec 82 T B + K Precision Model 1686 Christmas Stocking Stuffer Sep 88 DC Power Supply (HOR) Jan 17 Easy -to- Remember Frequencies Nov 86 78 How to Split a (Covington)(C) Jun 47 Exploring New Horizons Take the Speed Test ( Rakes)(CC) Apr High -Level Handles Jan 86 Oscillations (Carr)(HR) Sep 87 Tandy Preamplifier Look At Mobile Extenders, A Jun 86 Printers, The ABC's of (Thurber) Apr 43 Multimedia Personal Computer Not -So- Private Security Oct 89 Sensation! Jul (Scaduto & O'Brian)(G) 49 Pro Movie Specrum Video Capture Card, of the Airwaves, The Apr 90 Phantom Zoomer (Scaduto & O'Brian)(G) Mar 59 Media Vision (Scaduto & O'Brian)(G) Jan 56 Scanning Sky -High Surveillance Operations Aug Z -PDA Jan 18 Under Fire May 88 Team Monitor and Bass Subwoofer Speakers, PRODUCT TEST REPORTS (Feldman)(D) Scanning Nov 20 Feb 20. Mar 22,Apr 22 Summer Sports and Games Jul Rock Solid Sounds (Scaduto & O'Brian)(G) 86 May 24,Jun 21,Jul 20.Aug 21 Tracking Smokey Bear Technics SC -CH555 Mini Component Stereo Feb 86 Jun 21 AudioSource Model SS Three lI Underground Chatter System ( Feldman)(PTR) Surround Sound Processor Jan 18 Scanner Silencer, Build the (Pliler)(C) Sep 73 Telephone PCD 5870 Photo CD Player Feb 20 Kodak Model Sky -High Surveillance Bogen Communications Friday Personal!Office MC7100 Scanning 54 McIntosh Laboratories Operations (Saxon)(SS) Aug 88 Receptionist (Scaduto & O'Brian)(G) Jun Power Amplifier Jul 20 May 24 Under Fire (Saxon)(SS) May 88 Build Mitsubishi HS -U57 VCR Scanning the Call Blocker (Weeder)(C) Jun 31 Aug 21 Sharp Model MD -D10 MiniDisc Player ScanTrak 18 Golfball Finder, Ring Switch (Layne)(C) May 33 Apr 22 55 this Distinctive Sony MDS -101 MiniDisc Recorder Lil' Orbits (Scaduto & O'Brian)(G) Jan Directories. ProPhone Stereo Technics SC-CH555 Mini Component Tools 386 +, OrCad (NOR) Oct 18 CD -ROM (Scaduto & O'Brian)(G) Aug 51 Jun 21 Schematic Design System Hyton Products Phonedex Autodialing Mar 22 Schematic Symbols, An Introduction to (Young) Nov 46 Yamaha FIX-V870 Stereo Receiver Card File (Scaduto & O'Brian)(G) Jan 52 Telephone Schosche Industries Accumat Sound Barrier The Stick Voice/Fax /Modem ProPhone CD-ROM Apr 58 MultiLink Directories (Scaduto & O'Brian)(G) Aug 51 and Damping Material ( Scaduto & O'Brian)(G) Call Processor (Scaduto & O'Brian)(G) Jan 54 TMC M2000 Programmable 2 -Line Proximity Sensor ( Rakes)(CC) Jun 76 Screen Shots and Project Photography Dec 62 /Speakerphone 6 Made Easy (Blechman) Intercom Put Some "ReelMagic" in Your PC ( Spiwak)(MW) Aug Jul 55 Security (Scaduto & O'Brian)(G) Putting Together the NBS Set (Eliis)(AR) Jun 71 Mar 82 Build a Home Security System (Taylor)(C) Oct 31 Temperature Shift Meter ( Rakes)(CC) Build a Multi -Function Car Security Test Equipment Oct 47 System (Caristi)(C) B + K Precision Model 1686 DC Power Jan 17 Q SemWare Editor, The (Holtzman)(CB) Apr 76,Aug 76 Supply (HOR) Oct 24 Build a /an/the Servo Driver ( Yacono)(TT) Feb 57 Quit Smoking Circuit (Yacono)(TT) Feb 24 125 -MHz Logic Probe (Yost)(C) Sharp 50-MHz Frequency Counter (Weeder)(C) Nov 33 Model MD -D10 MiniDisc Auto -Ranging Digital Capacitance Aug 21 Player ( Feldman)(PTR) Meter (Bolles)(C) Nov 62 R OZ- 960011 Wizard Pen-Based Battery Amp -Hour Meter (Caristi)(C) Nov 51 Feb 51 Organizer (Scaduto & O'Brian)(G) "Gate -Dip" Meter (Veronese)(C) Nov 37 ( O'Brian)(G) Mar 57 (See Also Antique Radio, DX Listening, Ham PI -7000 Expert Pad Scaduto & Buying Used Test Equipment (Fonte) Jun 67 Radio with LCD Radio, Scanner Scene) ViewCam VL-E3OU Camcorder IC Engineering Digi -Field Field- Strength & O'Brian)(G) Apr 55 Dec 24 American Technology FM Sounds Miniature Viewfinder (Scaduto Meter (HOR) Nov 30 FM Radio (Scaduto & O'Brain)(G) Oct 71 Short- Circuit Protector ( Yacono)(TT) Test Gear for Your Workbench (Laron)(ED) Nov 3 Build Shortwave Testing the NBS Set (Ellis)(AR) Jul 73 a Nine -Band Shortwave Receiver Broadcast Finding (Jensen)(DX) May 84 Mar 33 Editor, Build Your Own (Holtzman)(CB) Apr 76 O(Williams)(C) Broadcasting in Singapore (Jensen)(DX) Dec 76 Text (Lisle)(C) Oct 62 Nov 30 a ne -Tube Radio Receiver Receiver, Build a Nine -Band (Wdhams)(C) Mar 33 THD Adapter ( Yacono)(TT) ( Pliler)(C) Jul 68 a Packet -Radio Tuning Indicator Jan 70 O'Brian)(G) Feb 47 Jun 44 Shred Your Manuals! (Holtzman)(CB) The Wave, Bose ( Scaduto & an SCA Adapter (McCormick)(C) Jul 43 the Scanner Silencer (Pliler)(C) Sep 73 Simple Amp ( Yacono)(TT) Dec 30 The Word on Kits (Thurber) Aug 39 Dec 55 Control, All About (Spiwak) Slide Scanner, Nikon Coolscan Thermal Calculations (Olivieri) /FM Radio Kit (HOR) Nov 24 Feb 45 Elenco Electronics AM (Scaduto & O'Brian)(G) THINK TANK (Yacono)(D) Jan 22,Feb 24,Mar 26,Apr 26 Ground Zero: The Other End 24 Charger, Build the (Caristi)(C) Sep 64 May 26,Jun 24,Jul 25,Aug of the Radio Spectrum (Thurber) Oct 55 Smart 30 41 Sep 24,Oct 24,Nov 30,Dec Fifties (Thurber) Mar 41 Vehicles are Here, The ( Siuru) Jan Hamming in the Fabulous Smart Addresses and Questions May 26 Lightning and the Radio Listening Software (See Also Multimedia Watch) Dec 30 May 44 AV Circuits Post (Thurber) ClarisWorks for Windows (Holtzman)(CB) Mar 80 Couse and Motion -Detecting for (Thurber) Feb 68 Beginner's Listening, Accessories CyberSoft NutriBase Personal Alarms, A Aug 24 -Band Apr 61 Sony ICF- SW100S World Nutrition Manager (Scaduto & O'Brian)(G) Displays and Discrepancies Feb 24 (Scaduto & O'Brian)(G) Nov 18 Radio Reciever Interactive Image Technologies Education and Alarms Sep 24 Jun 18 Radio Shack Electronics Workbench (HOR) Equipment and Chips AprP 26 Aug 18 PRO -2027 Desktop Scanner (Saxon)(SS) Aug 88 Logisym V3.2 Logic Simulator Software (HOR) More Muscle and Vehicle Projects Jul 25 (HOR) Oct 18 PRO-2030 Desktop Scanner ((Saxon)(SS) Oct 89 OrCad Schematic Design Tools 386+ Muscle Wire and Auto Stuff Jun 24 PRO -37 Handheld Scanner ( axon)(SS) Jan 86 Palm Computing PalmConnect Jan 22 Apr 63 On Displays PRO-51 Handheld Scanner (Saxon)(SS) Sep 88 Connectivity Software ( Scaduto & O'Brian)(G) Pinouts and Tools Mar 26 Apr 90 Oct 24 PRO-2028 Desktop Scanner (Saxon)(SS) Soldering Practice Kit, Elenco SP -1 (HOR) Feb 18 Some Hobby Circuits PRO-2032 Scanner (Saxon)(SS) May 88 Shop Circuits Nov 30 59 A Guide to Better (Thurber) Sep 37 Some PRO -44 Handheld Scanner (Saxon)(SS) Feb 86 Soldering,

www.americanradiohistory.comAmericanRadioHistory.Com Time -Delayed Model- Rocket Launch Control, Variable Frequency RF Oscillators (Carr)(C) Oct 41 A (Becker)(C) May 41,(LET)Aug 4 VCR TMC M2000 Programmable 2 -Line W Mitsubishi HS -U57 (Feldman)(PTR) May 24 Intercom/Speakerphone (Scaduto & O'Brian)(G) Jul 55 Hitachi VT -S772A (Scaduto & O'Brian)(G) Jul 52 Walkman Amp ( Yacono)(TT) Dec 30 Toner-Cartridge Recycling, Save a VFO Oscillator ( Rakes)(CC) Want to Operate W1AW? (Carr)(DX) Bundle with (Blechman Mar 71 Mar 82 Mar 86 Video Watching Multimedia (Laron)(ED) Touch Switch ( Rakes)(CC) Jun 76 Apr 2 -Distribution System, Channel Plus Tracking Smokey Bear (Saxon)(SS) WCES 94: Where's the Hype? Mar 86 9020 (Scaduto & O'Brian)(G) Sep 60 (Scaduto & O'Brian)(G) May 51 Transistor Matching Circuit (Rakes)(CC) Oct 82 Fox FoXapper TV/Cable Remote Control (Scaduto Weather Forecasting Triangle Waveform Generator (Rakes)(CC) Nov 74 & O'Brian)(G) Feb 53 Hitachi VT-5772A 5 -VHS VCR Build A/An Triangular Waveform Generator ( Anemometer (Simcox)(C) Rakes)(CC) May 79 with VCR Pluses (Scaduto & O'Brian)(G) Jan 37 Jul 52 Portable Barometer Trip to Mecca, A (Ellis)(AR) Feb 73 International Computers Closed Caption (Caristi)(C) Jan 31 Relative- Humidity Decoder (Scaduto & O'Brian)(G) Gauge (Caristi)(C) Jan 62 TTL Audio Oscillator ( Yacono)(TT) Nov 30 Jun 58 JVC JX -S700 A/V Selector Wheatstone Resistance Bridge ( Rakes)(CC) Mar 82 TTL Oscillator ( Rakes)(CC) Feb 80 (Scaduto & O'Brian)(G) Jul 56 Whole-House Entertainment TV Allowance Television Time Monitor, Kodak Model PCD Photo 5870 CD Systems (Scaduto & O'Brian)(G) Sep 49 MindMaster (Scaduto & O'Brian)(G) Jan 51 Player ( Feldman)(PTR Feb 20 Media Vision Wien -Bridge Oscillator ( Rakes)(CC) Mar 82 Two -Stage Receiver (Rakes)(CC) Aug 78 Pro Movie Spectrum Video Capture Card (Scaduto & O'Brian)(G) Jan 56 Will Ireland Return to Shortwave? MindMaster TV Allowance Television (Jensen)(DX) Jul 84 Time Monitor (Scaduto U & O'Brian)(G) Jan 51 Wire Antennas (Carr)(HR) Jun 84 Mitsubishi HS -U57 VCR ( Feldman)(PTR) May 24 Wizard Pen -Based Onkyo TX- SV717PRO WV Organizer, Sharp UJT Oscillator ( Rakes)(CC) OZ- 960011 (Scaduto & O'Brian)(G) Feb 80 Receiver (Scaduto & O'Brian)(G) Feb 48 Feb 51 Ultrasonic Circuits (Rakes)(CC) Dec 72 Sharp ViewCam VL-E3OU Camcorder with LCD Word 6.0 for Windows (Holtzman)(CB) Jul 76 Viewfinder Ultrasonic Receiver ( Rakes)(CC) Dec 72 (Scaduto & O'Brian)(G) Apr 55 Works-Band Radio Receiver, Sony Sony Handycam Snap! CCD -SC4 Underground Chatter (Saxon)(SS) ICF- SW1005 (Scaduto & O'Brian)(G) Nov 18 Feb 86 Camcorder (Scaduto & O'Brian)(G) Apr 56 Wrist Controller Watch, Unlden Videonics MX -1 Digital Video Mixer Casio CMD -408 (Scaduto & O'Brian)(G) Bearcat Bear Tracker BCT-2 (Scaduto & O'Brian)(G) Oct 63 Aug 53 Scanner (Saxon)(SS) Mar 86 Writing Pad, Inforite MP100 Video-Signal Detector ( Yacono)(TT) Dec 30 BC -2500 Handheld Scanner (Saxon)(SS) Dec 82 (Scaduto & O'Brian)(G) Apr 60 BC-890 Continuous Band Videonics MX -1 Digital Video Mixer (Scaduto Scanner (Saxon)(SS) Nov 86 & O'Brian)(G) Oct 63 SC- 15OXLt Sport Cat Scanner ( Saxon)(SS) Jul88 Viennese DX (Jensen)(DX) Feb 82 Y Universal Noise -Reduction System, ViewCam Camcorder with LCD Viewfinder, The (Panosh)(C) Jul 31 Sharp VL -E3OU (Scaduto & O'Brian)(G) Apr 55 Yamaha RX -V870 Universal Stereo Receiver Remote Control, Gemstar Virtual Reality By the Seat (Feldman)(PTR) Control Tower Mar 22 ( Scaduto & O'Brian)(G) Oct 69 of Your Pants (Spiwak)(MW) Jul 4 Year -Round Charger (Yacono)(TT) Jun 24 Using "Binocular" Coil Forms (Carr) Apr 67 VLF Oscillator ( Rakes)(CC) Feb 80 You Can't Please Everyone (Laron)(ED) Using Double Balanced Sep 2 Mixers (Carr)(HR) Oct 87 Voice Organizer, Voice Powered Technology (Scaduto & O'Brian)(G) Aug 56 z V Voltage Calibrator ( Rakes)(CC) May 79 Volume Meter (Yacono)(TT) Feb 24 "Z -Dice," Build the (Edwards)(C) Va Va Va Video Dec 46 (Holtzman)(CB) Nov 72 VXO Oscillator ( Rakes)(CC) Feb 80 Z -PDA Zoomer, Tandy (Scaduto & O'Brian)(G) Mar 59

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By Marc Ellis For those of you who handled by a standard and may not have been have just joined us, analog or digital multi - careful enough in setting we've been in the process meter. up and reading the instru- of rehabilitating and check- ment. It does take a bit of ing out a Sprague Tel - LET'S CONTINUE getting used to. Ohmike Model TO -4 ca- At the close of last pacitor /resistor analyzer. month's column, we had THE LOWEST RANGE Units similar to that one, checked most of the ca- Being a firm believer in intended for use by radio pacitance ranges, but were the "if it ain't broke, don't fá service technicians, were Tel-Ohmike still in doubt about the next - ir philosophy, I immediately marketed by the major ca- to- highest (0.1 to 50 µF) and abandoned my plans to pacitor manufacturers, Wrap -Up lowest (1 to 100 pF) ones. yank out and replace the including Sprague, Aerovox, The former was tested with 2 -µF reference capacitor and Solar. Hobbyist -grade a decade capacitance for the range in question. units, often sold in kit form, That I box providing values from 1 meant could move were offered by such corn - to 10 µF and it appeared right along to the next panies as Heath, Allied that all of the Tel -Ohmike's piece of unfinished busi- Radio, and Eíco. measurements were about ness, checking out the 1 -µF low. The latter couldn't TO -4's lowest (1- 100 -pF) capacitance be tested because I didn't range. have any capacitors in the In preparation for doing this right size range to serve as month's column, I had stopped C5 "guinea pigs." at the local Radio 2 MF I began this month's work Shack store to pick up R26 POWER FACTOR some 4.7 -, 47 -, 265n session with the thought and 100 -pF that the reference capaci- ceramic capacitors. Those would 20 -409'. tor for the 0.1 -50 -µF range allow me to check V2 had probably shifted in val- out both ends and the mid-

ue and that I'd have to dle of the range. I found replace it. The capacitor (2 that the tuning-eye shadow R24 µF) is labeled C5 in Fig. 1, wasn't as distinct on this which is the schematic for range, but after learning

the bridge circuit used in how to interpret it, I was Fig. 1. This simplified schematic shows how the TO -4 is that capacitance range. able to get satisfactory configured as a capacitance bridge on the 0.1 -50 -µF range. C5 - (See last month's and repeatable -results (2 .F) is the reference capacitance for the range; V2 is the column for tuning -eye tube used to balance bridge. a detailed explanation of when measuring the 47- how bridge circuits are and 100 -pF capacitors. Those analyzers are com- used to measure unknown The measurement at 4.7 monly available at capacitors or resistors.) pF was a different story, hamfests and antique -radio My first move was to re- however. The shadow was meets, not too difficult to measure each of the really vague here and diffi- put in good working order, capacitances offered by cult to read the same way and make excellent addi- the 1 -10 -µF decade box to each time. If I had to guess, tions to the antique -radio verify that the TO -4 was as though, I'd say that the TO -4 restorer's workbench. Ifs far off as I had thought. To measured this capacitance very handy to have the my surprise, the measured as somewhere around 10 means to find the value of values were now much pF Luckily, one isn't often an unknown capacitance closer to the nominal ones, faced with the necessity of and to check an elec- with the percentage error checking such a low value! trolytic or paper capacitor quite consistent with that for leakage. Most analyzers observed on the other CHECKING LEAKAGE IN will also measure resistance, ranges. The only explana- ELECTROLYTICS

but that's a function that I I tion can offer is that I was A very valuable feature of don't find useful too be- getting a bit tired at the the TO -4 is its ability to cause it's more easily close of last month's session check the leakage current

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ADJ. or VOLTAGE 0- 60/600 ELECTRONICS

(CLOSED ON 60V.POS.OF VOLT. SW4) CURRENT CIRCUIT, VOLTAGE CIRCUIT, BUTTON "A" NORMAL BUTTON "A" DEPRESSED Fig. 2. Here are circuits for measuring the leakage current of electrolytic capacitors. The configuration depends on the position of button 'A" (see text).

in electrolytic capacitors at age source, loading it actual working voltages up down as before so that the By Studying at Home to 600 volts. The circuitry supply voltage does not Grantham College of Engineering, that accomplishes that is change. However, the M1, now in our 44th year, is highly experi- in Fig. 2. It could be paralleled by shunt resistors shown enced in "distance education " teaching as at left or as R1 and R2, is now con- - configured by through printed a milliammeter correspondence- at right, depending on the nected as materials, computer materials, fax, the capacitor - position of front-panel but- in series with modem, and phone. the ton "A." test binding posts and No commuting to class. Study at The terminals labeled voltage source. your own pace, while continuing on your " +" and " -" are the bind- Connected that way, M1 present job. Learn from easy -to- ing posts for the capacitor reads any leakage current understand but complete and thorough under test. The two circuit that might pass through the lesson materials, with additional help points terminated in arrows capacitor being tested. By from our instructors. B.S. are connected to the ad- switching R1 in or out of the Our Engineering Technology is available in either of justable voltage output of meter shunt, switch SW2 sets Degree Program two options: the 1619 grid -controlled M1 to read 0-6 mA or 0-60 (1) The B.S.E.T. with Major Em- is the mA accommodating a rectifier tube. M1 OR wide range of currents. phasis in Electronics, front -panel meter. (2) The B.S.E.T. with Major Em- I checked several elec- When button "A" is de- phasis in Computers. my "junk box" pressed, Ml, with its trolytics from Our Computer Science B.S. Degree associated series resistors, using that function, and Program leads to the B.S.C.S. -the becomes a 0-600 volt- found that the results were Bachelor of Science in Computer Science. meter connected across within the tolerances sug- An important part of being pre- the capacitor -test binding gested in the TO -4's pared to move up is holding the right posts (in the right -hand ver- manual. As expected, ca- college degree, and the absolutely neces- sion of circuit). Using the pacitors that were very old sary part is knowing your field. ways voltmeter, the operator can exhibited much higher leak- Grantham can help you both -to learn more and to earn your degree in set the voltage delivered by age than newer ones. In the process. the rectifier to match the such cases, the operator is Write or phone for our free catalog. working voltage of the ca- advised to reduce the volt- Toll free, 1 -800- 955 -2527, or see age to a lower amount, pacitor under test. When mailing address below. closed, the switch just to the then to advance it slowly to right of the capacitor -test the nominal working volt- Accredited by Commission of the binding posts shorts out re- age, giving the capacitor a the Accrediting Distance Education and R9, convert- chance to "reform." sistors R8 and 1Yaining Council ing M1 to read 0-60 volts. If the capacitor is still in After setting the voltage good shape, the leakage GRANTHAM appropriately, button "A" is current will then be re- Engineering released, changing the cir- duced to an acceptable College of cuit to the one shown at value. Such was the case Grantham College Road left. The resistors formerly with the high-leakage ca- Slidell, LA 70460

in series with M1 pacitors that I happened to connected 65 still remain across the volt- test.

www.americanradiohistory.comAmericanRadioHistory.Com CHECKING INSULATION R23 V1 and through exposure to RESISTANCE IoMn high temperatures- there- While the TO -4 checks by increasing its resistance. electrolytic capacitors for R14 15 C6 The series -resistance type leakage Mn R7 by direct measure- 0.0047 12 loss is MF R16 of not important for ment of the current flowing IKn KO R15 FACTORY capacitors used in DC cir- through them at working 22 ADJUST. RO Mn 83 cuits because, unless there voltage, typical KA ADJ. current flow VOLTAGE is leakage, no current flows through paper, mica, and QUICK CHARGE through those capacitors to SW. R9 ceramic capacitors is so PART OF BUTTON ~A' I50V 25 be dissipated in the resis- small that leakage must be + - KA tance. However, capacitors tested by more indirect O O used in AC circuits (or in means. The test circuit for Fig. 3. The circuit for measuring insulation resistance of paper, pulsating DC circuits such that purpose is shown in mica, and ceramic capacitors uses a 12J5 triode amplifier. as power supply filters) do Fig. 3. pass current during charge/ As before, M1 is the front - Potentiometer R16, wired however, are subject to de- discharge cycles and can panel meter, the terminals in series with V1's cathode, is terioration because have such losses. labeled " +" and " -" are a factory -adjusted calibra- moisture and other con- A perfect capacitor the capacitor -test binding tion control located inside taminants in the would use no power, even posts, and the circuit points the instrument. The single - atmosphere can penetrate in AC circuits, because dur- terminated in arrows are pole switch located above their less- than -perfect seals. ing a discharge cycle, it connected to the adjusta- the capacitor -test binding Most restorers wouldn't would give back to the cir- ble voltage output of the posts, however, is a user - bother to check the wax cuit as much power as it 1619 grid -controlled rectifier operated "quick charge" jobs. They are considered had absorbed during the tube. button located on the front so unreliable that they are charge cycle. The extent to Tube V1 is a 12J5 triode panel. automatically replaced, which a capacitor is connected as a simple am- The quick charge button even if they are good, with imperfect-that is, the ex- plifier. Meter M1 measures is necessary because a sta- modern molded capaci- tent to which it uses power V1's plate current, which, at ble insulation resistance tors. Molded capacitors are through the combined the start of the leakage test, reading can't be obtained well -sealed and rarely give effects of leakage and se- is set to a standard value on a capacitor until it is fully trouble, even if stored for ries resistance -is repre- through adjustment of the charged. Capacitors larger long periods of time prior to sented by the power factor voltage supplied by the than 0.1 µF or so would take their use. which is a number repre- 1619. That is accomplished too long to reach that senting the percentage of by adjusting the voltage state,if the "quick charge" POWER FACTOR power loss. The power fac- (with nothing connected button were not held down A capacitor that is leaky tor must be measured at across the test binding for a few seconds. The but- can be imagined as having the frequency at which the posts) so that Ml's pointer ton temporarily shorts out a resistor equal in value to capacitor will actually be falls on a "set' mark lo- several series resistances, the leakage resistance used. cated at the - meter's full allowing 150 volts to ap- wired in parallel with it. An- Because electrolytic ca- scale position. pear across the capacitor other capacitor quality pacitors are especially The capacitor to be test- under test. problem can be repre- subject to losses through ed is now I connected tested the insulation -re- sented by a capacitor aging and exposure to across the binding posts. sistance measuring function having a series resistance. heat, and are most fre- Even the most minute leak- on several paper, mica, Such a resistance could be quently used in pulsating age through the capacitor and ceramic capacitors caused by poor internal DC circuits as power supply will increase the negative and obtained readings connections, or by capaci- filters, any quality test con- bias on V1, thereby de- consistent with the guide- tor "plates" (or electrodes) ducted on electrolytics creasing the tube's plate lines published in the that are not perfect elec- should include a power current and dropping the manual. However, I don't trical conductors. factor check. In the TO -4, meter pointer from its full - consider it as useful to the In the case of electrolytic power factor (at the AC line scale position. The greater restorer as the electrolytic capacitors, series resistance frequency) is measured the drop, the greater the capacitor leakage check. can be appreciable be- through adjustment of leakage through the ca- In general, the non -elec- cause one of the "plates" is power- factor control R26 pacitor (and the lower its trolytic capacitors actually the paste film sep- (see Fig. 1), as the bridge is insulation resistance). A encountered during a res- arating the Iwo metallic balanced to determine the scale is provided on the toration will be paper or surfaces that make up the capacity of an electrolytic meter (calibrated from mica. Mica capacitors al- capacitor. Not only does capacitor. The power factor 150 -20,000 megohms) so most never give trouble the paste have a much typically between 10 and that the insulation resis- and don't have to be higher resistance than a 60, is read directly from a tance of the capacitor can checked. The early wax- metallic conductor, but it scale associated with the be read directly. coated paper capacitors, tends to dry out over time- control.

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www.americanradiohistory.comAmericanRadioHistory.Com COMPUTER BITS

By Jeff Holtzman Should you buy a new in ZIF socket, the ability to in the middle of the first. machine or upgrade hold up to 64 MB of memo- Then I swapped in the your current one? During ry, Iwo VESA local -bus (VLB) new motherboard (corn - the past year and a half or slots, power management, plete with the new, faster so, I have gone through the and an Award BIOS. CPU and a single SIMM upgrade process. That pro- Don't get me wrong; holding 16 MB), and, hold- cess had its pluses and there was nothing wrong ing my breath, turned on minuses. Although I cer- with my old 486 mother- power. My heart was liter- tainly ended up with board a 486/25 for which I ally pounding as I thought, something that was better paid around $2200 a cou- "This cheap clone board is Buy or than what I started with, by ple of years ago. Does it going to fry my whole sys-

the I I time was finished, pain me that I got a new, tem." But it didn't. In fact, Upgrade? spent about as much on better, faster board for 1Á5th the system carne up the first

I upgrading as would have of what I originally paid? A time with absolutely no on a new machine. Further, little. But that's always the trouble, and has worked just way it is in the computer fine Columbia Dictionary of Quotations since. business. It seemed a little faster,

I Of course, could have but not nearly what I had just upgraded the video hoped, so it was back to Computers system (once seemingly the drawing board. As for speedy, it now seemed the kids' computer, after Electronic aids, particularly domestic computers, will about as fast as fresh mo- swapping in the old 486 help the inner migration, the opting out of reality. lasses in the Yukon), board, it was a heck of a lot Reality is no longer going to be the stuff out there, replaced the eight 1 -MB faster-just perfect for using but the stuff inside your head. It's going to be SIMM's with four 4 -MB jobs, CD- ROM -based learning commercial and nasty at the same time. wait another year, then buy tools such as the new F some sort of Pentium Columbia Dictionary of

screamer. But I just couldn't Quotations. J. G. Ballard wait. b. 1930 For one, I figured that by DISK UPGRADES British author buying a new mother- I next attacked the disk

board, I could pass the old subsystem. My old SCSI one on to my kids, whose adapter was an 8 -bit affair The Columbia Dictionary of Quotations, though not CD- based, old Dell 386 was simply un- made by Always Tech- provides a more varied set of quotations than is typical of most able to keep up with the nology. It had served me CD products. demands of multimedia well, but part of my system Windows computing. From upgrade involved using a while i got the exact com- that point of view I wasn't copy of Core! SCSI to con-

ponents I wanted, I had to just selfishly upgrading my trol a CD -ROM drive off the assume the responsibility for own computer; this was a same controller as the hard making it work together. family-wide upgrade as disks. Was it worth it? To me, yes. well! Of course, the $139 That was the dark part of But I wouldn't recommend it board then tripled in price my adventure. The set up for everyone. To help you because I had to pick up a basically worked, but had a make up your own mind, new CPU as well. Not to very nasty habit of just stop- here's the logic I followed: mention the 16 -MB SIMM for ping dead in its tracks in a One of the first things that the new board, which set totally unpredictable fash- attracted me to the idea of me back another $700. ion. For a while I just upgrading was the emer- After picking up the new ignored the problem. Even-

gence of super low -cost I motherboard, backed up tually I realized it was not

486 motherboards. I ended all the files on my present going to go away, so I up paying $139 for a board system to a Colorado 250 - started doing some trou- with: 256K of cache memo- MB tape drive. Luckily, I bleshooting. It wasn't too ry, the ability to install 11 made Iwo full backups, be- hard to track down the different types of 486 and cause it turned out that source of the problem. 486 -clone chips via a built- there were some bad files If I didn't load the man-

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and lnm00Ye IDe cvierce Now looks to the future and shows you of any FM rodlo Electronics what new video, audio and computer products are on You can IdenIlly more Man 1000 colors ar011 o1 the horizon. You'll find helpful, monthly departments such as Video News, Equipment Reports, Hardware Hacker, Audio Update, Drawing Board, Computer Connections, New Products, and more. All designed to give you instruction, tips, and fun. Electronics Now gives you exciting articles like: m w ,o rw

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www.americanradiohistory.comAmericanRadioHistory.Com ufacturer -supplied CD -ROM bought just a few months THINK TANK That removes current from device driver, everything earlier. To get the speed (Continued from page 29) the SCR and the relay turns worked fine. I tried upgrad- increase promised by the off. Now the thermistor being the drivers, several times 32 -bit VLB bus, I would need gins to cool to the point in fact, but to no avail. to get SCSI -II drives. That has ters, R6 and R7. The where U1 -b turns on. As Eventually I learned that the yet to happen. However, my threshold voltage is sup- cooling continues, U1 -a Always drivers disable soft- local clone shop is currently plied through R5, which is turns on and the output ware interrupts for a short selling brand 2.4 new -gig connected to a voltage di- circuit is complete, closing time, and that could cause SCSI -II Micropolis drives for vider made up of R4 (a the relay. Windows to crash. about $1100, complete with temperature- adjust potenti- To calibrate the circuit, I The solution was to up- a five -year factory warranty. ometer), R3 (a series resistor used a 60 -watt light bulb grade the SCSI adapter, I've got one those of tar- to set the range), and R1 (a connected to the and my contacts indicated relay. It geted for later in 1995. negative- temperature -co- was a simple procedure that Adaptec cards were to At that point in my up- efficient thermistor). use the heat from the the bulb standard for reliability grade I binge, had Let's assume R6 and R7 and a digital thermometer and compatibility. The next noticeably better Windows are set so that the voltage to set the trip points of the question was whether to performance (due to the buy a 16 -bit (ISA) or a 32 -bit faster CPU and double the TO HEATING (VLB) card. The 16 -bit card memory), and a reliable +12v DEVICE CIRCUIT cost around $200, and the system. But I still lacked the

32 -bit card around $400. I speed increase that was ended up springing for the the object of the whole R1 VLB 10K card (an Adaptec exercise. Next time we'll pick NTC R2 D1 1N4001 2840). The good news was up where this leaves off, 10K K1 that using the Adaptec and I'll point out a way of 12V card and drivers, I no lon- drastically increasing sys- ger needed SCR1 the Corel tem performance for a R6 50V drivers; in addition, the ran- more modest investment R5 20K 1A 10K CUT IN dom crashes unequivocally than I made. 1 See you then. R8 The stopped. bad news was R3 10K that there was no discerni- 4.7K R7 20K ble speed increase. Where To Get It R9 CUT 14 tOK Later I found out that al- OUT The Columbia Dictionary though the card R4 of Quotations 5K 1/4LM324 a1 conformed to the SCSI -II AApex Software 11 2N2222 standard, the three hard P.O. Box 13379 Reno, NV drives I had were all of SCSI - 89507 Tel. 702 -324 -4580 Fig. 3. Since the SCR I latches once it is turned on, and will vintage, including one I not activate without QI on, this circuit has built -in hysterisis.

at pin 3 of U1 is lower than comparators. The differen- that at pin 12. As the tem- tial is determined by the perature drops, the difference in the trip -point There is a resistance of R1 increases voltages. Setting the volt- and the voltage at the in- age at pin 3 100 -millivolts verting good time to inputs (pins 2 and higher than that at pin 13 13) decreases. When the produced a differential of call the IRS. temperature is low enough, about 3 degrees. Resistor both The best time to call comparators are satu- R2 is used to help straighten rated, so 01, SCR1, and the out the very non -linear re- 1 -800 -TAX -1040 is be- relay (K1) are activated. sponse of the thermistor. If tween 8 and 10 a.m.,or As the temperature rises, the input comparator inputs after 2:30 pm. on Wed- the voltage at pin 2 in- are transposed, the circuit nesday Thursday or creases. When the voltage can be used to control a Friday. It's just one at pin 2 is greater than that cooling device. more way we're giv- at pin 3, the gate current to -Bob Maclsaac, Nova ing you helpful advice. the SCR is removed. How- Scotia, Canada ever, the SCR will continue As with our other circuits, to conduct Internal Revenue until its anode - select K1 to handle the load Service to- Answers. Assistance. At Your Service. cathode current is inter- you have in mind. By the rupted. As the temperature way, you should set R4 ac- continues to rise, U1 -b turns cording to the cut -in off, thereby turning off Q1. temperature you want./

www.americanradiohistory.comAmericanRadioHistory.Com CIRCUIT CIRCUS

isolation By Charles D. Rakes ircuiteers, gather ULTRASONIC and a 680 -ohm Ihafaround the old work TRANSMITTER resistor. bench and join me in cele- Our first entry takes to the In the receive mode, the as brating our 100th get - air waves in the form of a piezo speaker operates together here at the Circus. CW (Morse code) trans- a sensitive microphone. Ul- We certainly have shared a ceiver. The circuit, see Fig. 1, trasonic signals travel from number of circuits since our uses the versatile, 567 the microphone through first meeting back in August phase -locked -loop IC as the two -stage amplifier to if of 1986, and it's my hope to the transmitter's signal - the input of the 567, and, do even better as we source generator as well as the signal's frequency is speed toward the next cen- the receiver's detector. The within the IC's bandwidth, the LED will light and piezo- More tury. But to do so, I need 567's dual circuit functions your help. Let me know allow for a much simpler sounder BZ1 will sing out for Ultrasonic through your letters to me transceiver design. each "dit" and "dah" re- via Popular Electronics, Here's a close look at the ceived. The receiver may Circuits what circuits you would like CW transceiver's receiver be tuned to the incoming to see appear, and any operation. With the tele- ultrasonic signal by adjust- ideas that you would like to graph key at S2 "up" ing R17. Of course, adjusting share in making our visits (open), the 567 PLL's input that potentiometer also more useful, educational, at pin 3 is coupled to the changes the transmitter's frequency. +9v In receive, transistor Q2 is R5 through R3 and R2{ C10 biased on 10K i R4, with its collector clamp- 1K II R17 06 R1 R13 L` 25K IH 2N3906 ing the 567's square -wave 1K 15K C5 output, at the junction of .1 LEDI R12 and R18, to ground. No .+N R12 * O C8 01 C6 can pass to the base BZ1 2.2K signal Pi .002 2N3904 1 --)1[-- 4r--Wr of Q1 in the receive mode. R18 The collectors of Q5 and D1 QSCA 8 7 6 5 4.7K 1 N914 { R6 2N3904 Q6 are like open circuits in S 10K receive mode and do Ut the 567 not load the speaker's (microphone's) output. R14 C4 2 2700 .1 The transmitter operates C7 02 Pg time the S2 is closed. Cl .22 2N3904 each I R9 When the key is closed, R3 C2 R10 2.2K diode D3 supplies a path to 10K .1 2.2Ki 4.44 AM R7 ground for BZ1, causing that 220K R4 R16 - to produce an au- 10K 33K i sounder D3 R15 -1N914 dible signal for each dit 6800 Q3 and dah transmitted. Also, D2 2N3904 1N914, Q2's bias is taken to ground through D2, allowing Q1 to sz pass the 567's square -wave its receive of the Fig. I. Get on the "air" with this ultrasonic CW receiver. For the greatest flexibility, signal on to the input and output frequency can be adjusted via R17. power amplifier and out through the speaker. You will need to build Iwo and just plain fun. If you output of Q3. Transistors Q3 to carry on a would like a personal reply, and Q4 are operating in a transceivers with a please enclose a self -ad- high -gain, two -stage audio - CW "rag chew" transceivers will dressed, stamped envelope. amplifier circuit. The piezo friend. The inside or out, but Now let's carry on where speaker is coupled to the operate be affected we left off last month with input of the amplifier the range can well as 71 more ultrasonic circuits. through a 0.1 -µF capacitor by the wind, as

www.americanradiohistory.comAmericanRadioHistory.Com PARTS LIST FOR THE ULTRASONIC TRANSCEIVER (Fig. 1)

SEMICONDUCTORS R17-25,000 -ohm, potentiometer UI -567 phase -locked loop, integrated circuit R18 -4,700 -ohm DI D3 -1N914 silicon diode CAPACITORS LEDI- Light -emitting diode, any color C6-0.1- .F, ceramic disk Ql Q5- 2N3904 NPN transistor CI 0.22 -µF, Q6-2N3906 PNP transistor C7- Mylar or similar C8- 0.002 -µF, Mylar or similar C9----47 µF, 16 -WVDC, electrolytic RESISTORS CIO 470 -µF, 16 -WVDC, (All fixed resistors are 1/4-watt, 5% units.) RIR2-1000-ohm electrolytic R3 R6- 10,000 -ohm ADDITIONAL PARTS AND R7, R8- 220,000 -ohm MATERIALS R9R12-2,200-ohm SPKRI -Piezo- tweeter speaker R13-15,000-ohm BZI -Piezo buzzer R14- 270 -ohm S1 -SPST switch R 15- 680 -ohm S2- Telegraph key R16- 33,000 -ohm Wire, solder, IC sockets, etc.

heating or air- conditioning MOTION DETECTOR output at pin 5 is coupled with the input connected tc air currents. You can trans- Our next entry is a motion to the base of Q1, and from a second piezo speaker mit around corners by detector circuit. The circuit- Q1's emitter to the input of (SPKR2) operating as a sen- bouncing the ultrasonic sig- ry, shown in Fig. 2, is in some the power amplifier made sitive microphone. The nal off walls, doors, or ways similar to our previous up of Q2 and Q6. The out- amplifier's output is coupled anything solid. If you wish, circuit. A 567 PLL IC oper- put drives the piezo to the 567's input at pin 3. you can experiment by ates in a dual- function speaker, SPKR1. When an in -band signal is changing the circuit's fre- mode as a signal generator The receive portion of received, the LED lights. quency to obtain the and an FM receiver. Here, the circuit operates as fol- The 567's FM output is greatest operating distance however, both functions are lows: Transistors Q3 and Q4 coupled from pin 2 to the and reliability. You can even performed simultaneously. are connected in a two - input of a very- low -frequen- tune the CW transceiver to Here's how that is done: stage, high -gain, audio -fre- cy single- transistor amplifier, a high (audible) frequency. The 567's square -wave quency amplifier circuit, Q5. The amplifier's output at Q5's collector drives a volt- +9V age- doubler circuit made C8I+ up of C11, D1, D2, and 012. R1 470.'4% R12 The DC output feeds a 0-1- 1K R11 25K mA analog meter. 15K C5 Q6 By placing the SPKR1 two piezo 1 2N3906 Q1 speakers one foot apart C6 2N3904 C4 in LEDA .002 and aiming them the Q2 same direction, toward a --)i-- 2N3904 non -moving solid object,

R3 the signal from the transmit- U1 10K ter's speaker will reflect 567 R4 R14 y back into the receiver's 2.2K 7 270f2 R6 speaker, and the frequency 2.2K T at the 567's input will be the C2 g;r, same as the one being C7 R5 R7 C9 7.22 2.2K 220K transmitted. R10 470 The AC output at pin 2 is 2.2K VN R9 D1 zero when the outgoing 220K 1N914 and incoming frequencies 1M +I( C11 are the same. However, R13 47 20K when the signal is reflected C12 Q3 47 2N3904 from a moving object, the Q5 D2 2N3904 1N9141 I M1 received frequency will be 0-1 MA either lower or higher than the transmitted one. If the Fig. 2. In this ultrasonic motion detector, if an object moves in front of the speakers, a signal is object is moving away from produced at pin 2 of the 567 PLL. the speakers, the received

www.americanradiohistory.comAmericanRadioHistory.Com +12V frequency will be lower; if PROXIMITY SENSOR the object is moving toward Our last entry this visit is the speakers, the frequency an audible proximity circuit will be higher. That is due to that can be used as a the Doppler effect. liquid -level detector, a prox- Regardless of the direc- imity- operated switch, or as tion of the movement, the a sensor for robotics proj- difference in the received ects. and transmitted signal will The circuit is shown in Fig. cause a low, audio -fre- 3. The pick -up sensor, BZ1, is quency difference output a Mallory Sonalert solid - to appear at pin 2. That state signaling device that pin -2 signal is fed through a is normally used as a low - in 470 -11F capacitor to the level alarm sounder. But of Q5, where the sig- our circuit it is used as a base a 3. This proximity sensor uses a common piezo sounder, nal is amplified and fed to variable -"Q" load- sensitive Fig. Mallory Sonalert, in a rather unusual way. a voltage doubler, and oscillator.

PARTS LIST FOR THE PARTS LIST FOR THE PROXIMITY SENSOR (Fig. 3) MOTION DETECTOR (Fig. 2) SEMICONDUCTORS SEMICONDUCTORS Ql- 2N3904 NPN transistor U1 -567 phase- locked loop, integrated circuit Q2-2N2222 NPN transistor DI, D2 -1N914 silicon diode Dl, D2 -1N914 silicon diode LED1- Light -emitting diode, any color. D3- 1N4002 silicon diode Q1- Q5- 2N3904 NPN transistor Q6- 2N3906 PNP transistor RESISTORS (All fixed resistors are is -watt, 5% units.) RESISTORS R1, R2- 2,200 -ohm (All fixed resistors are 1/4-watt, 5% units.) R3- 220,000 -ohm RI-1,000-ohm R4- 100,000 -ohm, potentiometer R2, R3- 10,000 -ohm R4-R6, R10 -2,200 -ohm CAPACITORS R7- R9- 220,000 -ohm Cl. C2- 0.1 -µF, ceramic disk R11- 15,000 -ohm C3-0.22-11F, Mylar or similar R12- 25,000 -ohm, potentiometer ADDITIONAL PARTS AND MATERIALS R13- 20,000 -ohm, potentiometer KI -12 -volt relay R14-270 -ohm BZl- Mallory Sonalert sounder, model SC628 source, etc. CAPACITORS Wire, solder, power Cl- C5- 0.1 -p.F, ceramic disk C6 0.002 Mylar or similar -4 what un- C7- 0.22 -4 Mylar or similar positive side of the sounder it a try and see can C8, C9- 470 -µE 16 -WVDC, electrolytic and its output is fed to a usual application you C10 -C12- 147 -pF, 16 -WVDC, electrolytic voltage -doubler circuit. The find for it. DC output drives Looks like we've just ADDITIONAL PARTS AND MATERIALS doubler's the base of Q2, which, in about used up our allotted Ml 0 1 -mA meter month. Before SPKRI, SPKR2- piezo- tweeter turn, operates the relay (K1). soace for this speakers As long as the Sonalert is we finish, however, I want to Wire, solder, IC sockets, power producing a sound, the re- correct an error in one of source, etc. lay stays energized. the circuits that appeared When a solid object is in October, 1994. In Fig. 7 in close proximity to that month, resistors R2 and then on to a meter circuit. Here's how the simple moved into the front of the sounder, the R3 are reversed. A few If you wish, the voltage - alarm sounder is turned the piezo element is sharp -eyed readers wrote doubler and meter can be a useful proximity sensor. A "Q" of the Sonalert's in to tell me about that one. removed and replaced 100K potentiometer, R4, sets lowered and internal oscillator circuit I hope it didn't cause any- with headphones con- the current fed to the Sona- to operate; as a one too much confusion. nected between the lert sounder. The poten- ceases result, the relay drops out. Until next time, you can negative side of C11 and tiometer is adjusted to a adjusting R4, send your letters to me at circuit ground. That will al- point where the sounder By carefully can be made Circuit Circus, Popular Elec- low you to listen to the just begins to make an au- the circuit sensitive. The proximity tronics Magazine, 500 -B Bi- difference -frequency signal dible sound. A single - quite sensor is a fun circuit to play County Blvd., Farmingdale, as objects move in front of transistor audio amplifier so why you give NY 11735. 73 the speakers. (Q1) is coupled to the with, don't

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www.americanradiohistory.comAmericanRadioHistory.Com DX LISTENING

By Don Jensen ometimes it is hard to fuses a lot of new listeners: ings time, the differences remember that not ev- "Can you explain the inter- are EDT +4, CDT +5, eryone who reads this national time used by MDT +6, and PDT +7 hours. in example above, column is an experienced shortwave listeners ?" asks So, our a.m. shortwave listener. In fact, Leif Anderson, Mankato, 0215 UTC means 2:15 the ranks of this wonderful MN. at the 0- degree (Green- hobby are swelling all the Sure, Leif. In this column wich) meridian, which is time with newcomers. Well, you regularly will see time equivalent to 9:15 p.m. EST EST plus 5 hours = because this is the first col- information given like this: (9:15 umn for 1995, I'd like to 0215 UTC, or 2130 UTC. 0215 UTC). to make all the newcomers a There are two things you The only other factor the Helping promise: During the coming need to know to use that remember is that when passes midnight, year, I'll try to include in information. UTC hour Beginners each column at least some The first is the 24 -hour the day /date moves basic information about (sometimes referred to as ahead. So 9:15 p.m. EST is to 0215 SWL'ing that may help you. the "military") time system. Monday equal To prevent confusion be- UTC Tuesday. If a station's tween a.m. and p.m., the schedule says that a cer-

hours from 1 a.m. to 11 a.m. tain program is aired at are designated 0100 to 0215 UTC on Tuesdays, you 1100 hours. Those from 1 should tune in at 9:15 p.m. p.m. to 11 p.m. are desig- Mondays, if you live in the nated as 1300 to 2300 eastern time zone. If you hours. Noon is 1200 hours. live in the CST, MST, or PST Midnight is 2400 hours, but zones, of course, your local one minute past midnight is listening times would be 0001 hours. Therefore, 0215 8:15 p.m., 7:15 p.m., or 6:15 is 2:15 a.m., and 2130 p.m., respectively. means 9:30 p.m. Though their local clocks The second thing to know will read differently, SWL's in is that UTC stands for Univer- New York, Chicago, Denver, sal Coordinated Time (the and San Francisco will all was be tuned in to the program Though most clandestine SW stations are quite secretive, some old term for that very same time, 0215, have replied to SWL's reports. In past years, this QSL card was Greenwich Mean Time, or at the sent out by Radio Vatan, a clandestine that targeted its anti - GMT, and ex -GI's will know it UTC. I hope that straightens regime political broadcasts at Iran. as Z or Zulu time). Because things out for you. the stations we listen to on Probably the best way to shortwave are located all LISTENERS' CLUBS Next, we hear from Willie do that is to respond to your over the globe, and the who is questions about shortwave listeners to which they Martin, Lancaster, CA and an listening. You can send broadcast are likewise both a newcomer them to me, Don Jensen, at widely scattered, it is useful old timer. He writes: "I was listener DX Listening, Popular Elec- to give all time references an active shortwave 1960's and early tronics, 500 -B Bi- County in a single standard time, in the mid military service Blvd., Farmingdale, NY the hour at the 0- degree, or 1970's, but meridian. That is overseas caused an inter- 11735. I look forward to Greenwich hearing from you! UTC. ruption of more than 20 In the meantime, I've got Listeners in North America years.

I from a few questions on hand to should know that UTC is "Now have retired like start the ball rolling. So, let's equivalent to Eastern Stan- the Air Force and would not waste any more time dard Time plus 5 hours, to resume SWL'ing. I've and get right to them. Central Standard Time plus been reading Popular 6 hours, Mountain Standard Electronics and I saw a to A MATTER OF TIME Time plus 7 hours, and Pa- reference in your column Here is a basic question cific Standard Time plus 8 the Southern California 75 about a subject that con- hours. During daylight sav- Area DX'ers and the Ameri-

www.americanradiohistory.comAmericanRadioHistory.Com can Shortwave Listeners' scanner monitoring. clandestine shortwave of these stations, which Club. I'd like to know the For a list of all 16, with voice, Luis? Canadian DX'er, others have been hearing addresses of those clubs so their addresses, mem- Robert Ross reports that Voz recently. I can contact them," bership fees and other Popular operates in Spanish CROATIA--5,920 kHz. Welcome back, Willie! pertinent information, send on 7,000 kHz on Tuesdays Croatian Radio is SCADS, a hobby radio noted at club a stamped, self- addressed and Fridays from 2300 to whose 0600 UTC with Croatian mu- membership is lim- business -size envelope to 0045 UTC, and on 3,500 kHz sic followed at 0605 UTC ited to southern California ANARC Club List, Associa- from 0200 to 0300 UTC. with listeners, can be contacted English news. tion of North American Ross has spoken with by writing one CYPRUS-6,195 kHz. The to 6398 Pheasant Radio Clubs, Dept. PE, 2216 of the station's represen- BBC English language pro- Drive, Buena Park, CA Burkey Drive, Wyomissing, PA tatives in Canada who says gramming heard 90620. The address of on this 19610. that Voz Popular operates a frequency ASWLC, at 0220 UTC re- which accepts 2,000 -watt transmitter from portedly is broadcast from members from anywhere in CLANDESTINE a secret site within relay transmitters on this the world, is 161 Ballad BROADCASTERS Guatemala, in the jungles Mediterranean Lane, Huntington Island. Beach, CA Next, Luis Garcia, San An- of the Sierra Madres near FRANCE -9,805 kHz. 92649. tonio, TX, writes, "Last month, the Tajulmulco volcano. Radio France International Those two are among 16 a Margaret Lewin asked airs English programming at organizations affiliated with about clandestine broad- VOA AUDIENCE 1220 UTC on this frequency the Association of North casters. I've never heard PROFILE and also, in parallel, on American Radio Clubs (AN- one of them. Are there any Approximately 92- million 15,530 kHz. ARC). Various clubs cover of those guerrilla stations adults regularly listen to the JAPAN -3,925 kHz. Radio the different aspects of the operating in Central or Voice of America's short- Tanpa is a home listening hobby, including -service South America? Where can wave and medium -wave shortwave, broadcast in Japanese. It medium wave I hear them ?" programs, the U.S.- govern- has been logged on the and longwave bands; FM How about an anti -gov- ment -sponsored west coast of North Amer- and iV DX signals; and ernment Guatemalan broadcaster reported last ica with jazz music and year. That breaks down to identification announce- some 25- million listeners in ments around 1015 to 1030 South Asia and the Near UTC. East; 21- million in Europe NEW ZEALAND -6,100 n the February, 1995 and the former Soviet kHz. Radio New Zealand In- Union; 20- million in Africa; ternational signs on at 0735 19- million in China; 6- million UTC, relaying the domestic in Latin America; and 1- radio -service programming. million in East Asia (other TURKEY-9,445 kHz. The Popular Electronics than China) and the Pacific. Voice of Turkey's English About 20 percent of those transmission from 2200 to Build your very own FCC Part 15 FM- stereo transmitter and become listeners tune in to English 2250 UTC features news, a sports announcer, DJ or soap actor in your home or at school. programming -the rest to commentary, historical fea- You can VOA's various troubleshoot your personal computer, and get it up and language tures, and Turkish music. You services. running like the pros do. Big buck savings here! can find it on 11,710 kHz at Research, the VOA says, the same time. The Editors reveal what the automotive industry's upcoming indicates that the American UKRAINE- 11,950 kHz. technology can do to avoid accidents while you are at the wheel. international broadcaster Radio Ukraine International Our home -brew, attracts low -cost frequency counter is small in size and an audience that is is heard in a one hour super accurate. Our plans are goof -proof! generally young, male, and English transmission begin- well-educated, though that ning at 2100 UTC. That PLUS outstanding columns and departments like Gizmo, Think Tank, does vary in different DX parts includes news and com- Listening, Scanner Scene, Computer Bits, Circuit Circus, of the world. mentary, as well as Multimedia Watch and a whole lot more! Ukrainian folk music. On Sale DOWN THE DIAL What's an SWL to do? December 15, 1994 Well, try tuning in to some

Pick up Popular 'CREDITS: Brian Alexander, Electronics at your favorite PA; Jim Lane, ONT CAN; Newsstand, Bookstore, Convenience Store William Mayer, PA; William McGuire, MD; Ed Rausch, NJ; Doug Robertson, or Supermarket CA; North "Jack, f think there are still American a SW Association, 45 few bugs in this automotive Wildflower Road, Levittown, PA navagation system." 19057

www.americanradiohistory.comAmericanRadioHistory.Com HAM RADIO

output circuit. K4IPV attenuator is a de- be to prevent overdriving By Joseph J. Carr, An for an at- vice or circuit that some circuit or device. An- A main use and one of my reduces a signal level by a other reason is to make tenuator, principal interests, is in specified amount. The at- comparison measurements. own the front -end of radio re- tenuation factor is usually A number of receiver mea- expressed in terms of deci- surements require SHIELD For RF circuits, an comparing Iwo signal lev- Our bels (dB). o attenuator's input and /or els, or the levels of two or for a standard output impedance is 50 more signals, ELECTRICALLY J2 ohms. That is, a circuit look- output level. SWITCHABLE input side Yet another use for fixed ATTENUATOR ing into either the BANK A Step or the output side of an attenuators is to "swamp" attenuator would see a 50- the inputs and outputs of B Attenuator ohm resistive load (by the circuits. Some circuits, such way, most attenuator cir- as LC filters, double -bal- Project cuits are bilateral, i.e. either anced mixers, and others, port could be used as ei- don't work as intended ther an input or an output). when faced with input or

SHIELD +12 VDC 6dB 20dB 12dB Fig. 2. The control -signal 113_ voltage (shown here as 8 ATTN3 ATI N1 ATTN2 +12VDC) should be +5VDC if 5 -volt 2,3,4,5,7 2,3,4,5,7 changed to 2,3,4,5,7 relays are used.

ceivers. By being able to o---r switch an attenuator in or INJ1 o + 41 0 out of the circuit, one can Kt effectively raise the dynam- K6 K4 11 ic range of the receiver by the amount of the attenuation factor while suffering only a small increase in the C7 ... C3 modern L C1 %L J noise floor. Most ham and SWL H.F-band re- b ceivers have at least one e A fixed attenuator, and many the basic step -attenuator circuit. The level of attenuation Fig. 1. Here's the schematic diagram for use a 6 -, 12 -, and 20 -dB three attenuator pads are selected via the inputs at A, B, and C. depends on which of the array that is similar to one later FIXED ATTENUATORS output loads other than the that will be presented in this column. In some re- A fixed attenuator pro- designed 50 -ohm system the attenuator can vides only one level of impedance. To overcome, ceivers, switched in or out of the attenuation. For example, a at least somewhat, prob- be signal path according to 6 -dB attenuator reduces lems caused by load - gain -control the power of the input sig- impedance variations, the automatic (AGC) level. nal by 6 dB. Fixed some designers place a 1- attenuators are commonly dB attenuator in series with Similarly, os- A STEP ATTENUATOR available with 1 -, 3 -, 6 -,10 -, the signal. in PROJECT 12 -, 20 -, and 40 -dB at- cillators will pull A attenuator consists tenuation factors. frequency if the load im- step several fixed attenuators The main use of fixed pedance varies, so, in lieu of that can be switched in or attenuators is to reduce the of a proper buffer amplifier, of the circuit as signal level by a fixed some designers will put an out For example, the 77 amount. One reason might attenuator in line with the needed.

www.americanradiohistory.comAmericanRadioHistory.Com ATTN3 ATTN2

K1 K2 K3

C A Fig. 4. Use this parts -placement diagram when assembling your board. The finished project should be placed in a metal enclosure; see text.

Avenue South, Thief River Figure 2 shows the exter- Falls, MN, 56701 -0677; Tel. nal connections to the 800 -344-4539) as part num- attenuator circuit. The entire bers Z663 -ND (5 volt) and circuit is built inside of a

Z664 -ND (12 volt). I used 12- shielded box or container volt units in my prototype (mine was homebrew), in because that is compatible order to prevent signal from with an AM BCB DX receiver leaking around the at-

that I am building; if you tenuator. The input and want it compatible with output jacks are whatever digital systems use 5 -volt form of coaxial connector relays. that suits your needs. Al-

Capacitors Cl, C2, and though I used RCA phono C3 are ceramic feed - jacks, any BNC, SO -239, or through capacitors. Look for other coaxial connector these parts in catalogs un- can be used. Switches der the heading "EMI Sl -S3 are toggle switches. filters." Any value from 500 Note that the diagram indi- Fig. 3. This foil pattern for the step -attenuator project pF to 2000 pF is usable. If it cates a + 12 -volt control is shown here full sized. is inconvenient to use the voltage; that voltage should panel feedthrough capaci- obviously be + 5 volts if 5- step attenuator project that do not have a convenient we are presenting this source for those devices, month (see Fig. 1) has 6 -, they can be obtained at a 12 -, and 20 -dB attenuator reasonable cost from pads, allowing the user to Ocean State Electronics select attenuation levels of (PO. Box 1458, 6 Industrial 6 -,12 -, 18 -, 20 -, 26-, 32 -, or Drive, Westerly, RI, 02891; 38 -dB. Signals presented to Tel. 401 - 596 -3080, inputs A, B, and c are used to Orders: 800- 866 -6626, set the attenuation level; Fax: 401 -596- 3590). more on that later. The attenuators are Turning to the circuit itself, switched in and out of the This photo shows the completed project ready for use. The attenuators ATTN1, ATTN2, circuit by relays K1 through feedthrough capacitors are shown along the lower edge of the and ATTN3 are Mini -Circuits K6. Those relays can be any enclosure. AT -20 (20 -dB), AT -12 (12 -dB), SPDT DIP delay, but if you and AT -6 (6 -dB) units. Those wish to use the printed cir- tors, or if the parts prove to volt relays are used in your fixed attenuators are cuit board (more on that in be too expensive for your circuit. housed in IC -like packages a moment), they must be budget (they can cost as A printed- circuit -board with 0.100 inch pin spacing EAC D1C05H (5 -volt) or much as $7 each from layout is shown in Fig. 3, so they will fit onto perfo- D1C12H (12 -volt) units, which some sources!), then use and its corresponding rated board intended for are available from Digi -Key 0.001 -µF ceramic -disk ca- parts- placement diagram DIP integrated circuits. If you (Fn. Box 677, 701 Brooks pacitors instead. (Continued on page 83)

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Confirm price and merchandise information 25 EASY DELICIOUS desserts $3.00: TTT Publications, PO with the seller, including brand, model, color or Dunedin, FL 34697.0219. Box 219 -(PE), finish, accessories and rebates included in the PERSONAL MISCELLANEOUS - price. EDUCATION /INSTRUCTION PENPAL DIRECTORIES! WITH Addresses: Corbett, 26085 Shaub Court, Clarksville, TN 37042. ELECTRONIC engineering. 8 volumes com- 2. Understand the seller's return and /or refund required. Free plete. $109.95. No prior knowledge policy, including the allowable return period, who TECHNICAL BOOKS, 1203 brochure. BANNER for returned merchandise and Grant Avenue, Rockford, IL 61103. pays the postage whether there is any "restocking" or "return" ANTIQUE RADIO CLASSIFIED charge. Free Sample! ,;só ` the product's warranty. Is there BUSINESS OPPORTUNITIES Antique Radio's Io- 3. Understand warranty, and if so, is it for a Largest Circulation Monthly. a manufacturer's EASY work! Excellent pay! 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By Marc Saxon Asmart -looking, new Get this: The Trident Communications handheld scanner, the TR -2400 has 1000 memory monitors know that it's easy Trident TR-2400, carries "In- channels! It also has 10 to sort out SAM flights from novations '94" honors search /scan ranges. The the others because their awarded by the Electronic frequency Monitoring coverage starts callsigns consist of the dis- Industries Association. Those at 100 kHz, and it goes to tinctive word "SAM," honors are given to the VIP Military 2060 MHz. That means it followed by digits repre- most innovative electronic covers low- frequency senting the individual products of the Aircraft year. beacons, as well as all AM, aircraft-for example, FM, SW and TV broadcast SAM -972 or SAM -345. The frequencies, and more, in aircraft used by the Presi- addition to the regular dent and Vice President are scanner frequencies. Wait, also SAM flights, and may there's more! be heard identifying as The handheld scanner SAM -26000 and SAM -27000 operates in AM, NFM, and when the President and FM modes, and can also Vice President are not receive single sideband aboard. Otherwise, they (SSB) mode signals. Tuning normally identify as Air increments are selectable, Force One and Air Force and go as low as 1 -kHz Two. steps for extra-fine tuning. VIP travelers get special The unit scans at 25 chan- attention from the media, nels per second. baggage handlers, and Despite its many features, everyone else. The use of c the Trident TR -2400 weighs SAM callsign announces to in at only 14 ounces, and ground stations that there is measures approximately 6 a priority status. Some scan- inches high by 2 inches ner owners know that SAM wide by 1.5 inches deep. It flights turn up on certain runs on four M batteries. A frequencies set aside for lot potential of in a small their exclusive use. You package! might want to try them, as For more information on they can get interesting. the versatile Trident TR -2400, Many people know that call ACI at 1- 800 -445 -7717 Air Force One has an air/ or 317 -849-2570. ground telephone downlink on 415.70 MHz. That is al- PLAY IT AGAIN, SAM most always operated in To many monitoring en- the clear, and sometimes thusiasts, SAM is more than you can also (poorly) hear the name of the world's the voice of the other party most memorable piano -bar replying, when it is repeat- performer. SAM is the mili- ed through the aircraft's tary acronym for "Special system. The uplink frequen- Air Mission," which is how cy is 407.85 MHz, and there the U.S. Air Force classifies are more than 60 ground those particular VIP flights transmitters located carrying heads of state, throughout the U.S. and Proving that "good things come in small packages," the Trident cabinet members, senators Canada. That ensures that TR -2400 offers 1000 memory channels and much more and in a congressmen, and Air Force One and Two, or handheld 14 ounce unit. high- ranking officers. any SAM flight, will always

www.americanradiohistory.comAmericanRadioHistory.Com sheet stock. That material is be able to make contact simultaneous conversations. HAM RADIO available from hobby via the private "Echo -Fox- The signal extended to (Continued from page 78) shops, model shops, and trot" phone circuit. The 50 kHz from the center Fig. 4. An etched shops that cater to amateur ground transmitters are all frequency. Putting the scan- is shown in PC is also available. jewelers (typically called remotely controlled from ner into AM mode, I slowly board this "rock shops" or "lapidary the White House Communi- sifted upward and down- You can either build or buy one shops" in the Yellow Pages). I cations Center ("Crown'). ward through the garbled board yourself, FAR Circuits (18N640 bent the stock into the When Air Force One and maze in 5 -kHz steps. I was from Dundee, IL, shape of the box, and then Two are on the ground, or able to extract a few of the Field Court, The isn't avail- soldered the joints using a flying in a local area, they conversations, although 60118). price but standard 150 -watt soldering have available the with poor quality and with able as of this writing, FAR made my pro- gun. "Yankee-Zulu" private tele- some heterodyning. Fred at phone circuit, which has This column has received totype for a very (indeed, NEW PARTS CATALOG seldom been reported. The a lot of mail over past reasonable price a low -cost When preparing this col- aircraft operates on months providing informa- FAR tends to be PC boards, and umn, I called Frank 171.2875 MHz, with the tion on, and asking source of with- Pellicano at Ocean State ground station, located lo- questions about, SAM VHF/ will make your design set -up fees Electronics to make sure cally, on 162.6875 MHz. UHF communications. Looks out the terrible other sources they carry the attenuators, While in flight, Air Force like it's a topic that interests that many along with some of the One and Two are some- our readers. I hope that this charge). version of other Mini -Circuits products. times accompanied by month's column provides a Because rry is go- Frank told me that they now civilian aircraft, such as good start for those who the digital attenuator inside of have their 1994 -1995 cata- commercial charters or air- want to know more. Re- ing to be mounted chassis, it was not log on the street. If you are liners used by the media. member, also, that SAM a receiver a wonder- an electronics hobby build- Communications between missions outside of North necessary to buy cabinet er, especially a ham -radio the pilots takes place on America operate in SSB ful manufactured then that catalog is it. I a shielded builder, 129.525 MHz. mode on long -range comfor made of 1.5 -inch sure to be of real interest to The home base for all munications frequencies enclosure out width, 22- gauge, brass you. SAM flights is Andrews Air below 30 -MHz. Force Base in Maryland. At that base, several scanner - MESSAGE FROM THE band frequencies are re- BERMUDA TRIANGLE Earn $1000 served exclusively for Reader William G. Cave A Week While You Learn High communications with SAM lives on Summerland Key, aircraft, and they can be Florida, which he points out Paying VCR Repair. copied working Andrews is at the intersection of Hur- Earn While You Learn .. . from hundreds of miles ricane Alley and the Secrets Revealed . . . William away. Listen for Andrews to Bermuda Triangle. Train at Home to police identify as "SAM C.P" (Com- started listening If you are able to mand Post) on 141.55, 361.6, radio stations back in the work with small 372.5, and 378.1 MHz. VIP days when the stations op- hand tools and pos- helicopters at Andrews use erated around 2400 kHz. sess average me- 'r chanical ability, you MHz. Then he followed them to 141.70, 292.2, and 375 could earn top dol- Some of the more eso- the 30-50 -MHz band, and lar part time or full teric communications to the 150-160 -MHz range. time. Our learn by doing method teaches you how believed to be from Air Now he writes that the po- to work on VCR's without boring unnecessary Force One have been lice agencies he wants to electronic basics. For Free Information Package Send Coupon to: 246.95, 305.55, monitor have gone to 860 noted on Foley -Belsaw Institute, 6301 Equitable Road, 322.75, 326.0, 336.8, 345.5, MHz with digital scrambling, Kansas City, M0 64120 terminals, 361.6, 362.35, 366.0, 390.0, trunking, data aw rCCheck VCR lc ea` °Ny) 397.05 MHz. Those fre- and whatever. He asks if this r, Dept. and or another El VCR Repai 62239 quencies have variously all could mean the end of H/ghPaying Computer Repair, Dept. 64139 been observed by scanner police scanning. Caner TV/Satellite Dish, Dept. 31036 Field Repair, Dept. users as using AM, WFM, I don't believe so, al- Advance VCR 65027 Repair, Dept. 66037 USB, LSB, and multiplex though it certainly inhibits / FULF9 \ Camcorder BFLSUwJ Dept. 67037 downlink transmissions. Not the ability to monitor police Fax Repair, most ac- $1ace1926 Printer Repair, Dept. 68036 long ago, I tuned in 361.6 in the largest and MHz and observed a multi- tive agencies. Thousands of Name plex operation going on. medium and small agen- Address cies don't feel that those That meant that it was a City single wide signal that con- costly systems are needed ) gate Zip 83 tained several independent for their purposes. CIRCLE 154 ON FREE INFORMATION CARD

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As a member of the ELECTRONICS ENGINEERS' Electronics Engineers' BOOK CLUB MN Blue Ridge Summit, PA 17294-0860 Book Club . . . Circuits ... you'll enjoy receiving Club bulletin_. every 3 -4 YES! Please send me The Encycopedia of Electronic - shipping/handling & weeks containing exciting offers on the latest Vols. 1, 2 & 3 (5489C), billing me $9.95 plus as a member of the Electronics Engineers' Book books in the field at savings of up to 500 /o off of tax. Enroll me according to the terms outlined in this ad. If not satisfied, I regular publishers' prices. If you wan the Main Club may return the books within 10 days and have my membership do nothing and it will he shipped Selection cancelled. automatically. If you want another book, or no book at all, simply return the reply form to us by Name the date specified. You'll have at least 10 days Address to decide. And you'll be eligible for FREE BOOKS through the Bonus Book Plan. Your only obliga- City tion is to purchase 3 more books during the next State 2 years, after which you may cancel your Zip Phone at any time. must remit in U.S. funds drawn membership Valid for new members only, subject to acceptance by EEBC. Canada ordering Instrucdona. A on U.S. banks. Applicants outside the U.S. and Canada will receive special t." 1995 EEBC Publisher's price shown. shipping/handling charge & sales tax will be added to all orders. PPIF195 85

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You can create fantastic laser cilloscope probe to win safety INDOOR /OUTDOOR light effects anywhere with the certification from Underwriters TEMPERATURE ALARM handheld Micro Lase 650 from Laboratory (UL). UL certification The Model 401012 indoor/out- Portable Edmund Scientific. About the also qualifies the probe for safe- door temperature alarm from size of a portable radio, the ty certification by two Extech provides simultaneous compact device uses diode international standards -setting readings of indoor and outdoor Laser Light laser technology to create organizations: the European temperatures on a large 1.5- effects that pulsate and change Economic Community's IEC (In- inch LCD. The compact unit Show in response to musical input. ternational Electrotechnical offers a wide measuring range Commission) and Canada's of - 58 °F to 170 °F (accurate to CSA (Canadian Standards As- 0.1 °). The indoor temperature sociation). The probe can be sensor is built in; the external used by industrial motor and sensor includes adhesive back- power supply designers as well ing for easy mounting and ten as automotive and aircraft ser- feet of cable. A single -point vice personnel and consumer - electronics repair technicians. The P5100 high -voltage probe offers a bandwidth of 250 MHz and the lowest input capacitance (less than 2.75 pF) of any probe in its class. Those capabilities allow users to ex- ploit the high- bandwidth capacity of Textronix' TDS300 -, 400 -, and 500 -series digitizing oscilloscopes, or maximize the alarm for the external sensor performance of other manufac- warns the user that the temper- turers' scopes. ature is either above a high limit The unit can be connected di- or below a low limit. A dual - rectly to your stereo system's point alarm for the external sen- amplifier output, or its own inter- sor alerts the user that the nal microphone will pick up temperature is either within or ambient sound. Four separate outside the range of two set controls allow you to vary the points. The alarms are both pattern design and size to audible and visible (red /green create unlimited variations. The LED). light show is most effective at The 401012 indoor /outdoor projection distances of up to 50 thermometer, complete with wa- feet, but the Micro Lase 650 will terproof outdoor sensor, cable, project as far as 200 feet. It is The probe has accessories built -in stand, and AAA battery, most dramatic in darkened designed for safely gripping costs $19. For additional infor- areas. It runs on four 'AA" bat- large, high -voltage test points. mation, contact Extech teries, or with the included 117 - Those accessories include a Instruments Corporation, 335 volt power supply. retractable hook tip, useful for Bear Hill Road, Waltham, MA The Micro Lase 650 (order gripping bolts up to 1/4-inch in 02154 -1020; Tel. 617-890 -7440; number E52 570) costs $499. diameter, and for holding the Fax: 617-890-7864. For more information, contact probe in place while making CIRCLE 103 ON FREE Edmund Scientific Company, signal measurements. Using the INFORMATION CARD Department 14A1, C999 hook tip, rather than securing Edscorp Building, Barrington, the probe with wires, eliminates MINIATURE NJ 08007; Tel. 609 -573 -6250; a high -voltage- testing safety SOLDERING IRON Fax: 609-573-6295. hazard. Designed for user comfort, the CIRCLE 101 ON FREE The P5100 high -voltage Antex Model G/3U miniature INFORMATION CARD probe costs $199. For further soldering iron from M.M. New- information, contact Tektronix, man features a protective heat HIGH -VOLTAGE Measurements Group, P. O. Box shield. The heating element is OSCILLOSCOPE PROBE 1520, Pittsfield, MA 01202; located under the tip for op- The Model P5100 2.5 -kV probe Tel. 1- 800 -426 -2200. timum thermal efficiency. The from Tektronix is the first high - CIRCLE 102 ON FREE pencil -thin plastic handle always voltage (above 1.5 -kV) os- INFORMATION CARD stays cool, and the iron fits

www.americanradiohistory.comAmericanRadioHistory.Com boosted in heavily carpeted and Electronic upholstered ro m' or reduced in rooms filled with hard surfaces. Security Intended for use with virtually any receiver, preamplifier, or integrated amplifier, the Architect is a "set and forget" component. Mini Long Range FM Voice Because it should be adjusted Transmitter (3 mi) Ultra Sensitive - only during information, it uses with fine tune, range control, more! Detects comfortably in the hand for rotary potentiometers instead of even whispers! FMX1 Kit and Plans $4950.. hours of electronic assembly sliders, which are more prone to Tiny Telephone fiddled with by the curi- work. The 18 -watt unit puts out being FM Transmitter 12 -dB the same power as a bulkier 30- ous. Plus and minus (3 ml) - automatically operates when phone is watt iron. It heats up to 750 °F in adjustments provide ample con- used. Crystal clear clarity with fine tune and only 45 seconds and recovers trol for reducing acoustic range control. TELX -1 K1t and Plans $ rapidly. The G /3U measures 61/2 problems and maximum output Both Easy-to-Build Kits Above only $49.50! inches in length and weighs 3/4 at usable frequencies. speaker op- of an ounce. It uses slide -on The Architect Extended Play .-7-dt tips that come in more than 40 timizer has a suggested retail styles, including needle points, price of $189. For more informa- Telephone I( chisels. tion, contact AudioControl, spades, cones, and Recording System - $129.50 The Antex Model G /3U mini- 22410 70th Avenue West, - Automatic - Crystal Clear - Easy to Use - ature soldering iron, including a Mountlake Terrace, WA 98043; Connects to Any Phone - Automatically controls standard tip, has a list price of Tel. 216 -775 -8461; and records both sides of the conversation on our $21.95. Replacement tips are Fax: 206-778-3166. extended play recorder. Caution - check local priced from $1.95. For addi- CIRCLE 105 ON FREE CARD laws as some states require an alerting beeper. contact M.M. INFORMATION tional information, TAP2OX Ready-to-Use System only $129.50 Newman Corporation, 24 Tioga WEARABLE FREE CATALOG with order or send S1.00P &H Way, P. O. Box 615, 4111.1A4-1 141C, NSA, Check, Cash or COD. Marblehead, MA 01945; "HEADLIGHTS" Bright Eyes Pro Headlights from .. NIJMITED Send or Fax Orders to: Dept pe16 Tel. 617- 631 -7100; PO Box 719, Amherst, NH 03031 Wahl Clipper Corporation pro- Fax: 617- 631 -8887. Orders: 800-221-1705 FAx 6o3- 672-s406 Tel 603-673.4730 to CIRCLE 104 ON FREE vide a practical solution INFORMATION CARD repair and maintenance situations, in dimly lit areas, that both hands for the job tcctronif. T SPEAKER BOOSTER require - D c#4,.. , . in compact and none for holding a flash- ` Bookshelf, -wall, and speaker systems don't have to light. Worn like eyeglasses, the sound small, according to lightweight headset features a ., ,i I..Y. II ,kn...... ,. ,4.1 AudioControl. The Architect small bright flashlight on either electronic processing system is side of the head. As the techni- designed to improve the perfor- cian moves from task to task, so mance of small loudspeakers. does the light, always aimed ts,,,,,,,,, The heart of the device is its directly at the job at hand. speaker optimizer system, described as "a sort of tool kit for Your Ticket To building better sound from l- and 3 -way speaker systems with 4 -, 6 -, or 8 -inch woofers. 45-Hz (low bass), 150 -Hz (mid SIJCCESS bass), 700 -Hz (midrange), and Over 28,000 technicians have gained admit- tance worldwide as certified professionals. 12 -kHz (treble) band centers are Let your ticket start opening doors for you. provided to optimize small ISCET offers Journeyman certification in at where adjustment speakers Consumer Electronics, Industrial, Medical, is most advantageous. Bass Communications, Radar, Computer and output can be carefully en- Video. For more information, contact the Electro- hanced, and strident midrange International Society of Certified West Berry Street. The Bright Eyes Pro Head- nics Technicians, 2708 can be mellowed. Highs can be Fort Worth, TX 76109; (817) 921 -9101. tailored to a particular room- lights have a suggested retail price of $13.95. For additional Name information, contact Wahl Clip- Address per Corporation, 2900 North City Locust Street, P. O. Box 578, State Zip -0578; Tel. Sterling, IL 61081 _Send material about ISCET and 815 -625 -6525; becoming certified. Fax: -625 -1193. 815 _Send one "Study Guide for the FREE CIRCLE 106 ON Associate Level CET Test." En- 87 INFORMATION CARD Lclosed is $10 (inc. postage). J

www.americanradiohistory.comAmericanRadioHistory.Com Popular Electronics

The HDTV Resolution s. ein---_ teas:. Get Widd +ö M!M.W .s..,aor .11 Er the are jr" iseed / .. 441,41,- .11r. se.kt; Popular Electronics Plans for the world's plaything zaniest - Popular Electronics back issues are available September 1989 although quantities of some issues are nearly exhausted. Here's an opportunity to complete your wifbwaros Wit real collection, ORO or obtain a selected back issue you cannot find elsewhere. This offer is valid 1_12pular Electronics only when using the coupon on this page or a photo copy. t,...... ,>,4 eSo...et.k - -- Special Back Issue Offer! IiiN sum mi

iWed tt.e Snaye, Senthet Please circle the issue(s) ordered!

Jan. Feb. Mar. n` ;.« Apr. May June July Aug. Sep. Oct. Nov. Dec.

1987 1 2 3 4 F 11 12 not available 1988 issues 1 1987 -1988 back 23 24 Put together your Macintosh own computer 1989 25 26 27 28 29 30 31 September - 32 33 34 35 36 1991 1990 37 38 39 40 41 42 43 44 45 46 47 48

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

1111.1 ( 1.11 Y,yt.t' 1992 59 60 61 62 63 64 65 66 67 68 69 70 I .el '4 t.. itor `= 1993 71 72 73

...°::.. Note: Issues prior to November 1988 are "Hands -on Electronics" -the predecessor of Popular 11.1. tin Electronics. How to determine cost! ; 112;1.814,...... Price per copy Quantity United States Canada Foreign Ell] 1 -5 $6.50 US $6.50 US 6 -11 5.50 the Tesla Coil 5.75 $8.00 US Build 12 -23 5.00 that went square! 5.25 7.50 - 24 and more August 1989 4.50 4.75 7.00

Prices include handling and shipping. Prices subject to change. All orders payable in U.S.A. funds only, via in- bpular Electronics ternational 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. :..¡oute.tte Game Visa MasterCard Yt.otto Selector USA Bank Check US or Int. Money Order w" r [Note: Credit Card minimum order is $15.00.) C.. .. Credit Card Number Exp. Date / t OR

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t City State ZIP 1=1 Send Orders To: CLAGGK, Inc., P.O. Box 4099, Farmingdale, NY 11735. Sorry, no telephone orders. Take a chance on RIM our Dice- Roulette project- April 1989

www.americanradiohistory.comAmericanRadioHistory.Com At the very end of the manual (after TELEPHONE LINE ANALYZER the instructions for use), there is a 10- (Continued from page 24) question multiple- choice quiz, so you can gauge your understanding. Rather than asking questions about structions only show you how to per- the quiz focuses on how form each test to get a go /no -go the analyzer, phone sys *ems work. result. The detailed instructions, how- the whole, the kit is easy to build ever, fully describe each test and On functions well. The instructions for show you how to correct problems and and use are clear and that give bad test results. construction The completed kit, with its custom panel concise. When you build the analyzer, end up with a device that looks The Tutorial. For those interested in meter and label, looks as good (and you and thoroughly understanding phone works as well) as any manufactured unit. and acts like a commercial unit, in the process. Add to that technology, the tutorial offered with learn a lot the the fact that the unit can save you the analyzer kit is invaluable. The tu- hear his or her own voice through some money, and the kit's cost is more torial's first section-Telephone Oper- receiver at an acceptable volume ation-describes the connection be- level. than justified. If you want more information on the tween a phone and the phone Line Analyzer, contact company's central office. It also de- Kit Assembly. From the soldering Telephone Electronics, Inc. at the address scribes, in general terms, what hap- tips in its beginning to the assembly Elenco der, or circle No. 119 on the pens when you place a call. instructions that follow, the manual in- given ear Free Information Card. The next section, which is on rotary - cluded with the kit is thorough and dial telephones, presents a simple di- easy to follow. There's a checklist -style agram of an old -style phone for use parts list for inventory checking, as with most of the later sections. Of well as step -by-step assembly instruc- course, it explains how contemporary tions with pictorial diagrams (a la phones are more modern in design, Heathkit). Like the parts list, there is a step so you but the remainder of the text is written box next to each assembly Invest in such a way that the diagram is can check it off when it is completed. useful nonetheless. The first set of instructions describes a stamp The next section discusses a phone's how to install parts on the PC board. It hook switch, which detects if the then goes on to explain the process the cab- phone is off -hook. In that section, the for mounting the meter onto values of both off-hook current and inet. The next two sections show you voltage are presented. how to connect the modular jack and Both rotary and tone dialers are dis- modular socket to the PC board. Next, cussed next. During the discussion of instructions for wiring the meter to the old -style pulse dialers, the timing of board are given. The final -assembly dial pulses for both the US and Europe instructions describe the physical unit. is supplied. A mechanical explana- construction of the tion of how pulses are generated is After the assembly sections, the also given. The section on tone dialers manual provides calibration instruc- need is a Save covers the frequencies used to gener- tions. For calibration, all you DC ate DTMF (dual -tone, multi -frequency) small screwdriver, a 20- or 40 -volt signals, and how they are generated source, a 20 -mA current source a bundle in a touch -tone type phone. (which can be improvised by using an of a stamp, you can get the lat- Next, a phone's transmitter is dis- adjustable voltage source), and a For the price est edition of the federal government's free cussed. Both carbon granule and meter to measure voltage and cur- Consumer Information Catalog. It lists microphone mouth pieces rent. You only need to adjust Iwo po- electret- more than 200 free or low-cost publications For contrast tentiometers to complete the calibra- are reviewed separately. on federal benefits, jobs, health, housing, tion procedure. purposes, the section on receivers education, cars, and more, to help you save uses a speaker analogy to explain A component -check section money, make money, and spend it a little how all types of receivers work. comes after the calibration pro- more wisely. The section on ringers, like the other cedure. The component -check sec- sections in the tutorial, is thorough. tion guides the user through the So stamp out ignorance with our free Both the electromechanical and examination of the polarity of compo- Catalog. Send your name and address to: piezoelectric types are discussed in nents and connections, and is a pre- depth. cursor to the troubleshooting section Consumer Information Center The little- understood, induction -coil that follows. Because the kit is pretty Department SB troubleshoot- Pueblo, Colorado 81009 balancing network is covered in the simple to put together, last section. As the instructions explain, ing is reduced to nothing more than that part of a phone allows the user to checking your soldering. 89

www.americanradiohistory.comAmericanRadioHistory.Com VCR hear a dial tone again. Press the ring Cross TELEPHONE -LINE Reference SIMULATOR switch once and verify that a ringing (Continued from page 39) NOW Find the right Part sound can be heard in the telephone handset (it for your VCR should sound like an au- A power switch was not used in the thentic ring signal). Pressing the Ring prototype. Although a power control switch again or hanging the phone is not necessary, you can add an SPST up will terminate the ring sound and type toggle switch in series with the return the dial tone. primary of T1. Plug a second telephone into the Connect the main board to the line 2 (test) jack. Pick up the line -1 power -supply board using short phone and again press the ring lengths of insulated wire. Wire the switch. Verify that the line -2 phone's square pad to the square pad, the bell is activated. It should ring with a center -tap (cr) pad to the center -tap cadence similar to a standard ring pad, and the remaining pad to the pattern. remaining pad. Try the remaining operational Be sure to trim any long component modes. For example, set the mode to leads. After assembly, clean the solder "A" to have line 2 ring whenever line 1 flux off the circuit boards. Commercial is lifted off -hook. solvents are available that do a terrific With the job of removing the flux residue. Beep- and Cycle-Mode Operation. Mount the two circuit boards on To use the beep or cycle modes with ISCET VCR short standoffs in an enclosure of your the delay feature, connect an an- OtOSS REFERFACE choice. Be careful when mounting swering machine or telephone to line the power board; do not allow it to 2. If you are using the cycle mode, be This 270 -page reference contains come in contact with the conductive sure to also install a phone in the line -1 both model and part- number cross - surfaces of your cabinet! Position the jack. Start line -2 ringing by lifting the references updated to include 1992 power board in your enclosure so that line -1 phone -hook units. off (cycle mode) or T3 is a minimum of two inches from T1 pressing the ring switch (beep mode). VCR's in a are made few factories and T2. If they are placed too close While the test line is ringing, you can from which hundreds of different together you may hear power -line AC adjust the delay potentiometer from brand names and model numbers hum on the telephone audio. 10 -90 seconds by viewing the LED dis- identify cosmetically- changed iden- play; the display will tical and near -identical manufactured show a readout Test and Check -Out. Disconnect If units. Interchangeable parts are very of Ito 9. the delay cycle has already any telephone common. An exact replacement part equipment plugged started (as seen by the chasing LED into may be available only a few minutes the line -1 and line -2 phone jacks. pattern), you can press and hold the away from you even though the Remove the JU1 power -up -mode ring switch to review the delay -count manufacturer supplier is out -of- stock. configuration jumper. Install the JU2 setting. You may be able to cannibalize scrap CPC -configuration jumper. Adjust R14 When line 2 is answered, a series of units at no cost! (which sets the audio level) to about beeps will be generated that will The ISCET VCR Cross Reference the middle of its range. make most voice -operated (VOX) an- Turn is pre -punched for standard loose - on AC power and verify that the swering systems stay on the line (if they LED leaf binding. . .$38.00 plus $3.00 for display shows "r." for a moment are operating correctly). If you want to shipping for each Reference. then shows "n." (normal mode). Press force the answering system to the mode switch and verify that it can periodically hang up, just use that Claggk Inc. be cycled through the five different unit's VOX time limit VCR CROSS REFERENCE OFFER switch. modes (n, A, P.O. Box 4099 b, c, and d). Keep line 1 off-hook if using the cy- Farmingdale, New York 11735 Remove power and install the JU1 cle mode. After the answering ma- Name configuration jumper. Turn on AC chine (or telephone) hangs up, it will Business power and verify that the LED display be cycled on again every 10 -90 sec- Address shows "r." for a moment then shows onds, depending on the R35's setting. City "A." (automatic mode). At any time you can cancel the beep State Zip Set the unit to the normal mode or cycle modes by pressing the Mode Phone ( "n. "). Connect a standard telephone switch. Enclose $38.00 for the Third Edition of the ISCET to the line 1 (main) modular phone VCR Cross Reference and $3.00 for shipping for each Reference. jack. Pick up line 1 and verify that a Conclusion. Using Ring -It! couldn't The total amount of my order is $ dial tone can be heard. If you are be easier. Plug the equipment to test Check enclosed -do not send cash. or please charge my credit card. using a DTMF phone, dial a digit and or demonstrate into line 2 and use the Visa MasterCard Exp. Date _// verify that the dial tone stops and the line 1 telephone to place calls to it. Card No. digit is shown on the LED display. Now that you're ready to use your Signature Hang up New York State residents must add applicable local the phone; then lift the Ring -It! project, reach out and touch tax to total. handset again. Verify that you can someone. Lsales J

www.americanradiohistory.comAmericanRadioHistory.Com cost SURFACE -MOUNT In the near future, SMC's should r less than their insertion mount equiv- from page 48) (Continued alents. NEW BOOKS Availability is of more concern than 10. Inspect your work under a magni- price. Yet the situation is improving for the Project Builder fying glass. Especially look for solder daily. Most electronics mail -order dis- SMC's that they BP350- ELECTRONIC bridges. tributors have a line of Electronic BOARD GAMES -$6.00 sell in single -lot quantities. True, not all Board Games Unfortunately, there will be times Twenty novel electronic when you'll need to remove a com- of your favorite transistors, IC's, diodes, board games that you can ponent (wrong component, compo- and indicators are yet available in sur- build from the plans in this book. Whether you in component face -mount configurations. But most nent backwards, are interested in motor severely misaligned, etc.). As a gener- are. The box entitled "SMC Distributors" racing, searching for al procedure, dip solder wick into liq- lists a few of the major distributors buried treasure on a des- island or for gold in uid flux, place it over the lead or pin, where the author has purchased ert Fort Knox, spinning the a iron. SMC's. Call, fax, or write to those and and apply heat with soldering wheel of fortune, or doing a musical quiz -there You When all possible solder has been re- other companies for a catalog. is something for you to build and enjoy! moved, the component should lift up will be surprised at the extent of their with a slight pull. SMC offerings. PCP119- ELECTRONIC MUSIC AND MIDI PROJECTS Practice, Practice, Practice. So far, $14.95 the basic characteristics of the most Save cash by building the popular surface -mount components, MIDI gadgets you need. Want a MIDI THRU box, the knowledge of how to handle and program change pedal, solder them, and sources for their pur- Metronome, analog echo chase have all been dealt with. But unit. MIDI patchbay or switcher? Over 16 prac- is still one important step left to there tical and very useful music and MIDI projects -all complete the SMT learning experi- in this book! The projects are explained in detail ence: SMC soldering practice. After with full instructions on assembly. you have practiced awhile, you can BP301- ANTENNAS A soldering iron, a tweezers, a vise, and move on to SMT project building -the FOR VHF AND UHF a magnifying glass are the only tools you subject of a future article. So for now, $6.00 need to get started. how do you get a hold of both SMC's From installing a TV or FM antenna to setting up PC to practice surface - and a board a multi- antenna array for mount assembly techniques? There shortwave listening or are two ways to go about it. amateur radio, this book VHF One, you can disassemble a stuff- explains the basics of and UHF antenna opera- ed, surplus SMT PC board -that is, re- tion and installation. The move the SMC's from it and solder text describes in easy -to- understand terms the new ones in place. Be sure, however, essential information about how antennas works, the advantages of different antenna types, and SMC's. Never attempt to to use new how to get the best performance from an an- reattach a previously removed tenna. SMC -it just isn't worth it. Two, Electronics Goldmine, listed in Mail to: You might already have these necessary the "SMC Distributor" box, sells two Electronic Technology Today, Inc. materials on your workbench. low -cost SMT "Learn to Solder" kits that P.O. Box 240 contain a PC board and a teaspoon Massapequa Park, NY 11762 -0240 Getting Your Hands on SMC's. full (which means hundreds) of SMC's. Shipping Charges in USA & Canada Hopefully, you're eager by now to ob- They're great kits to practice with. $0.01 to $5.00 $1.50 530.01 to $40.00 $5.50 tain some surface -mount compo- Contact the company for details. $5.01 to $10.00 $2.50 $40.01 to $50.00 $6.50 $10.01 to $20.00 $3.50 $50.01 and above $8.00 is way you choose to nents and see what the excitement Whichever $20.01 to $30.00 $4.50 SMT assembly tech- all about. Doing so will probably be practice your Sorry, no orders accepted outside of USA and easier than you might have thought. niques, try getting started as soon as Canada. All payments must be in U.S. funds only. There are two factors to consider: cost possible. Awhole new world of project Number of books ordered. and availability. The good news is that building is waiting to open up to you. Total price of books $ chart) $ with regard to both, things are defi- Note: For a more in -depth discus- Shipping (see for Subtotal $ nitely moving in the right direction. sion of surface-mount technology Sales Tax (NYS only) $ During the late 1980s, SMC's were electronics experimenters, you might Total enclosed $ 20 to 30 percent higher in price than want to pick up a copy of the author's Name equivalent, through -hole compo- Third Edition of Electronic Project De- Address nents. Today, however, pricing is at sign and Fabrication, Macmillan Pub- City State ZIP parity with traditional components, at lishing Co., 445 Hutchinson Ave., Llease allow 6 -8 weeks for delivery. 91 least for the more common devices. Columbus, Ohio 43235.

www.americanradiohistory.comAmericanRadioHistory.Com MULTIMEDIA WATCH If you or your business Freex. Prime #1 is about a island without a clue to your depends on making 13 -year old boy- turned- whereabouts or purpose. (Continued from page 8) phone calls all around the country hero who defends school- The story emerges in bits or the world, then three girls, fights crime, and more. and pieces from clues left

Records, But I only had new discs from Pro CD will Hardcase #1 is about a scattered about various lo- these discs a couple of be of interest and great use super -human who gives up cations. Just one hint: There months at the time of this to you. Select Phone is a 4- crime -fighting to pursue a is more to this game than writing (early September!). disc set that contains every movie career, and then first meets the eye. I've only The New Grolier Multimedia telephone directory in the confronts his past and re- spent a few hours with it, Encyclopedia is a valuable United States, business and turns to fighting crime. and I've barely scratched multimedia reference residential, all linked to Those comic books are the surface. Fans of adven- source containing photos, complete addresses. The in- brought to life using brilliant ture games will become charts, maps, video, anima- formation can be used as graphics, real voices, visual addicted in short order. tion, and more. With a low you see it, or it can be effects, music, and sound Myst sells for about $55. price of $149.95, it's a terrific exported to other pro- effects. Each disc contains If you're into ham radio, investment for the whole grams. Free Phone is AT&T's only one comic book, but then you might want to family. toll -free directory on one each is well worth its list subscribe to AmSoft's The Everyone has heard of disc, and Canada Phone price of $24.95 as the discs World of Ham Radio on CD- the Guinness Book of Rec- contains every business really show off what multi- ROM for $99. Published ords. That book has and residential white -page media is all about. Besides, I three times a year, the disc probably delivered the final directory in Canada. Euro think these #1 -in- the -series includes over 750,000 new verdict in more bets than Pages is a similar directory CD -ROMIX will be collector's and previous call signs, any other. The answers to on a single disc that con- items, so I'm even keeping making it easy to create what's the biggest, the tains listings for 150,000 the boxes intact. mailing lists. The discs also smallest, the fastest, and the European companies. That If you're a baseball fan, include over 7000 ham -re- tallest are all there. How- is great if you do business and the 1994 strike didn't lated programs. ever, you might not be overseas. All of Pro CD's ruin your appetite for the To finish up this month I've aware that the book is new discs can now run in game, you will not want to got some software that's available on CD -ROM, as Windows as well as DOS. miss Microsoft's Complete available only on floppy well. It's a whole new way of Multicom Publishing has Baseball 94. The history of disk, but I think it deserves looking at world records. a CD -ROM for everyone in the game, its teams, and mention anyway. First, a The 1994 Guinness Multi- the family. Mom will proba- over 1000 of its players, couple of utilities for Word media Disc of Records bly like Better Homes and from the earliest days to the for Windows, Doc -To -Help contains every single word, Gardens Healthy Cooking past season, are all pre- and Quicture, both from record, and picture from with its detailed recipes, di- sented in an entertaining WexTech Systems, Inc. I'm a the book, plus video clips, rections, and printable and easy -to -use format. A big fan of Word for Win- audio, and sound effects, shopping lists. Ingredient full complement of player dows, and those two utilities not to mention the search proportions can be scaled and team statistics from make it even more ver- capabilities of CD -ROM. In automatically based on the 1901 to 1993 will settle any satile. Doc -To -Help lets you addition, the CD -ROM also number of servings. Mom argument in a hurry. There's create Windows on -line comes packaged with a should also like Better even a trivia challenge with help using Word for Win- paperback copy of the Homes and Gardens Com- more than 900 questions of dows, and Quicture book. The disc/book combo plete Guide to Gardening, varying difficulty. Strike or no reduces the time required has a list price of $49.95. the comprehensive guide strike, that $79.95 title is a to load, scroll, print, and If you have an interest in to gardening fundamentals. definite hit. save Word for Windows armchair traveling through Dad might like those two If you are interested in documents that contain Medieval France and other discs, too! Children be- multimedia games, you graphics. places during the Middle tween the ages of 3 and 9 without a doubt have al- Last but not least, TIE Ages, then check out will love Dandy Dinosaurs, ready heard about Myst Fighter from LucasArts is a MindQuest: Medieval which includes stories, arts from Broderbund Software. mind -boggling, Star Wars

France from Blue Mountain and crafts projects, and Well, I finally got around to action game, but this time Software. That $79.95 disc more. A cute stuffed dino- checking it out for myself, you work for the Dark Side, lets you take a multimedia saur is also included. and I am happy to say that and your mission is to de- tour of European architec- A while back I looked at everything you've heard is stroy the Rebel Alliance. TIE ture from the middle ages a CD-ROM/Xi multimedia true. The game is beautiful Fighter, the sequel to X- while listening to Medieval comic book from Davidson to look at, easy to play, and Wing, contains dazzling ac- music. The disc also gives & Associates, Freex #1, the a breeze to install. Its lei- tion graphics and hours of you access to maps, time- first story in the Freex series surely pace will not, fun. The best action games lines, definitions, and from Malibu Comics' Ultra - however, appeal to die- still must be played from a narrated tours. Medieval verse line. I recently hard fans of action games. hard drive, and TIE fighter is France is the perfect break enjoyed two other CD- In short, you are deposited no exception. It is well worth from your regular work. ROMIX's just as much as on a seemingly deserted the disk space, though.

www.americanradiohistory.comAmericanRadioHistory.Com base. The bobbin is a dumb -bell FULL- OR PART -TIME JOB /BUSINESS: 1 WWV RECEIVER shaped piece of ferrite material (Continued from page 52) glued to the base. Lay out three 13 cm Learn VCR repair! lengths of #32 to #38 AWG enam- Career -level home study. signal germanium or Schottky units. eled wire in parallel. Wind the three Master easy- to-learn, high- 4,., repairs without buy- with wires 10 times around the bobbin as a Selecting two diodes matched ing costly, high -tech instru- forward -bias characteristics is not ab- set, as shown in Fig. 5B. Solder the wire ments. Free literature: send solutely necessary; however, don't mix ends to the base pins as shown in Fig. or call 24 hours a day. completely different types of diodes 5C. 800-223-4542 in the mixer! The core permeability and the Name _- Ag,- The CA3240 op -amp was specified winding inductance are not critical as Phone l ) because of its low cost and moder- long as the winding acts as a trans- Address ately low, input -noise characteristic; former at 10 MHz with low inter -wind- City State Zip the alternative HA series units listed in ing capacitance. The windings should The School of VCR Repair Road the Parts List are preferred for their not be glued within the bobbin. PCDI, 6065 Roswell Dept. VRA34I, Atlanta, Georgia 30328 lower noise figures. The MC1458 and other "741" derivatives should be Test. After completing the assembly, avoided. With a single RF- amplifier apply power to the circuit and check Be a computer Zener diode D3; stage, the receiver is noise limited by the voltage across repair expert! the op -amp, so lowest -noise units are the voltage across it should be be- Career -level home study to the overall operation of tween 3.0 and 3.6 volts. Connect a course. Learn all about PC re- beneficial pairs, troubleshooting, instal- the receiver. good ground to the receiver- a cold lation, upgrading, servicing. As for component replacement water pipe is preferred. Static should Open your own business; Adjust become a more valuable em- and substitution, most passive com- be heard through the speaker. ployee. For free literature: ponents are not critical and can be trimmer capacitor C11 until a WWV send or call 24 hours a day. replaced with close values. If you signal is audible; then peak C11 for the 800 -223 -4542 find the Zener diode, it can be best reception. The local- oscillator can't Name Age -. frequency will initially be offset from simulated by connecting five 1N914's Address Phone ( ) WWV so you'll probably hear the beat in series. City State Zip capacitor C1 note. Adjust trimmer The School of PC Repair Transformer Winding. Transformer zero beat. PCDI, 6065 Roswell Road is verify Dept. JJA341, Atlanta, Georgia 30328 T1 is a home -made unit, consisting of If a MW signal not heard, is J 40 closely wound turns of #26 AWG that the audio circuit functioning; U1 3 to U2 pin 3 enameled wire on a 1/4 -inch diameter check the input of pin air -core form, as shown in Fig. 4, with with an audio signal injector, while lis- the receiver output. Check taps at 21/2 and 10' turns from each tening to TANDY end; after each tap, the windings pro- the local oscillator's operation using ceed in the same direction. Hot -melt an oscilloscope, dip meter/monitor, or NATIONAL PARTS glue can be used to secure the wind- other frequency -test device, or listen Start off the New Year with usl ings to the form. The coil does not for the 10 -MHz, local- oscillator signal require a tuning slug in the core. on another 10 -MHz receiver. Semiconductors Fig. 5 shows the assembly details for If the audio amplifiers are function- Tools/Test Equipment T2 transformer). Shown ing, but no signal is heard, verify the (the mixer Led's /Lamps Filters electrically in Fig. 5A, T2 is wound on a winding polarity of T2 and the winding ferrite bobbin taken from a sub- order on T1. If you have a dip meter, Crystals Inductors the resonant miniature 10.7 -MHz IF transformer or use it to verify and set Sockets Capacitors used in older frequency of C11/T1 to 10 MHz. Check detector coil universally and much more pocket, auto, and console FM radios. the receiver with a marker generator calibrated for 25 -, 50 -, or 100 -kHz in- IF transformers are typically color -co- NO MINIMUMS ded brown, green, or blue, and the crements. If a signal is still not heard, FREE detector coils are typically black or wait a few hours and try again. Verify ORDER TOLL at both white. The 10.7 -MHz detector coils are your ground connection 1- 800 -322 -3690 easily confused with 455 -kHz transfor- ends -the ground is essential for the mers, which also use black and white short antenna. as identifying codes. The internal ar- After the initial circuit test, it may be rangement of the detector coil differs necessary to re -trim capacitor C11 for "CATALOG KNOCKS SOCKS OFF" from that of a 455 -kHz transformer in optimum reception. If C11 does need that it has a single winding, while the re- trimming, re- examine your anten- For our free Catalog, just send your to: 455 -kHz unit has two. na attachment to the case and see if name and address Disassemble the transformer or coil, you can't reduce the stray capaci- Consumer Information Center remove the tuning sleeve, the wind- tance by increasing insulation width Department KO Pueblo, Colorado 81009 ings, and any tuning capacitor in the or separation. 93

www.americanradiohistory.comAmericanRadioHistory.Com DX BEAM -AIMER * ** BE SURE KEYBOARD IS IN CAPS -LOCK MODE! * ** (Continued from page 42) GREAT CIRCLE DISTANCE AND DIRECTION

TO DETERMINE THE SHORTEST DISTANCE FROM POINT A To Lines 580 -620 first determine the POINT B, AND THE DIRECTION FROM A TO B. ENTER THE LATITUDE AND LONGITUDE IN DECIMAL DEGREES OF EACH POINT. lengths of arcs F and E, even if they are THESE CAN BE FOUND FROM A MAP, GLOBE OR ENCYCLOPEDIA, in different north -south hemispheres. Similarly, lines 630 -700 calculate the WHEN READY TO PROCEED, PRESS ENTER? angle at the North Pole (point I) between the origin and the destination, taking into consideration their east - west locations. These calculations are * ** BE SURE KEYBOARD IS IN CAPS -LOCK MODE! * ** also designed to define the smallest of two possible spherical triangles, POINT A NAME ? LOS ANGELES since one triangle could go around POINT B NAME ? ZANZIBAR IS ZANZIBAR EAST OR WEST OF LOS ANGELES (E OR W)? E the globe in a reverse direction! The remainder of the program is LATITUDE OF LOS ANGELES? 34 NORTH OR SOUTH (N OR S)? N concerned with solving for the spher- LONGITUDE OF LOS ANGELES? 118.5 ical triangle between the North Pole, EAST OR WEST (E OR W)? W the origin and the destination, and LATITUDE OF ZANZIBAR? 8 then printing the results. The remark NORTH OR SOUTH (N OR S)? S statements show the formulae used. LONGITUDE OF ZANZIBAR? 40 EAST OR WEST (E OR W)? R Lines 710 -730 print the North Polar Angles, and then lines 740 -820 do the calculation for the length of the arc D. LOS ANGELES IS 34 DEGREES NORTH AND 118.5 DEGREES WEST The computer uses "radians" for the ZANZIBAR IS 8 DEGREES SOUTH AND 40 DEGREES EAST ZANZIBAR IS OF calculations. A radian equals 57.2958 EAST LOS ANGELES degrees. Therefore, one degree NORTH POLAR ANGLE TO POINT A (LOS ANGELES) IS 56 DEGREES. NORTH POLAR ANGLE TO POINT B (ZANZIBAR) IS 9H DEGREES. equals 0.0174533 radians (1 divided NORTH POLAR ANGLE BETWEEN POINTS IS 158.5 DEGREES. by 57.2958.) DISTANCE A -B IS This conversion is shown in line 750 8830.028 NAUTICAL MILES ( 14'7.3171 DEGREES). DISTANCE A -B IS 10178.14 STATUTE MILES. and is used in lines 770 -810. The formula to calculate the COSine of arc D DIRECTION A-B IS 42.22064 DF.uMA CLOCKWISE FROM NORTH. is shown in line 760, and used in line Fig. 2. The program begins by presenting a brief overview of hoer to enter location data. 820. Then it requests the data, processes it, and returns its results. Now it is necessary to get the "inver- se cosine," usually called the "arc - the direction from A to B, measured BEAM.BAS (GWBASIC source code) cosine," to convert the calculated clockwise from north, is printed by line and DXBEAM.EXE (executable from variable D (actually COSine D) to an 1010. Line 1020 ends the program. DOS) for $5, postpaid in the US, $7 for angle in radians. Some computers foreign orders. Order from Fred have the arccosine function in BASIC, Modifications. If you are a true per- Blechman, 7217 Bernadine Ave., West but most don't, so a conversion for- fectionist, you'll probably want to Hills, CA 91307. Specify 5.25- or 3.5- mula is used in line 840, instead. modify the program to accept input inch disk. Line 860 converts the value of an- in degrees, minutes, and seconds gle D from radians to the more famil- rather than decimal degrees. Also, iar degrees, then line 890 calculates you might wish to add a DATA state - O PEN nautical miles by multiplying degrees ment to declare typical locations and I8M by 60, since there are 60 nautical their latitudes and longitudes, so that miles in one degree on a great circle. you can type in the city name and Line 910 converts nautical miles to have the program look for the coordi- statute miles (which are 1.1515 times nates. To assist you, Table 2 shows the nautical miles.) Lines 890 and 920 approximate geographic coordi- print the results on the screen. nates of some well -known cities, and Lines 930 -1010 calculate the direc- typical results from using this program. tion between the origin and destina- Bear in mind that different types of tion, using the spherical trigonometry BASIC will calculate slightly different formula in line 940. Here again the results beyond one or two decimal arccosine formula is used to deter- places. mine the angle G in radians, which is For the convenience of readers then converted to degrees by line who would like to use this program on "Remember, you need a hard drive followed 990. Line 1000 assures that the smaller an IBM PC or compatible, the author is by a micro chip." of two possible triangles is used, and willing to supply a disk with both DX-

www.americanradiohistory.comAmericanRadioHistory.Com Supplement to Popular Electronics 1995 Fpu1ar Electronics January

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Great looking, high quality, black padded carrying 1 100 for $15.00 1000 for $120.00 I case. Originally made for portable cellular phones, the main interior compartment is 10' X 2 3/4X r. LASER POINTER PRICE Ideal for pull -out stereos, phones, cameras or test NEW LOW equipment. Zippered compartment for thinner items IR such as handbooks, tapes, CDs and batteries. Velcro UNIVERSAL fastener on flaps and interior CONTROL compartments. Handle and REMOTE adjustable shoulder strap. The # OPON-670 -210 The Fox 400 Tr wireless infrared infiniter''. red spot up to 100 meters. An excel- remote control works with most TVs, Projects a bright lent business or educational aid. Settings for continu- VCRs, cable and audio devices. or flashing beam. LED indicator. Low battery indi- Works with all major brands and ous Includes 2 AAA batteries.Hi -tech ergonomic gun- lots of not -so-major brands. Use cator. metal gray and black case. it to replace lost IR remotes or to combine up to four remotes CAT # LP -210 $iU9 into one und. User friendly. Includes complete instructions and an 800 CANVAS COVER phone number if prob- X 128 DOT lems should occur. CAT # CSE -1 $5.00 each 480 Fully guaranteed. VINYL (SIMULATED LEATHER) COVER Requires 3 AAA LCD ASSEMBLY CATI CSE -2 each batteries (not $6.00 included). Hitachi N LM2158 CAT # IR -400 W/ BAFFLE Originally bud'. for Federal Express, these 3" SPEAKER brand -new assemblies consist of a heavy -duty plastic display housing with a metal mounting "HI -8" VIDEO bracket. Housing size: We don't know 13.18" X 4.9V X the original (USED) 1.2'. Inside CASSETTE application for the housing these speakers, but and easily 8 mm Video Camcorder Users!. they're well made and will removable handle a lot more power SONY Hi -8 is a stan- than their size would Top quality, metal particle 120 dard Hitachi indicate. According to our minute video cassettes. Used 480 X 128 primitive tests they provide good for a short time, then bulk - graphic and mid range response at 30 watts or bet- erased, each cassette has its alphanumeric ter. The well -constructed 3" 6 ohm speaker has a own plastic storage box. New, display with built-in drivers. Requires an external heavy magnet and a foam -edged paper cone. It's con- these high quality cassettes sell controller (HD61830 or equiv.). Display area is 9' X servatively rated at 7 watts, but the T deep, fiberglass for considerably more. 2.71. Module size is 10.6' filled baffle enables it to sound good at much higher Satisfaction Guaranteed. h X 4.33 ". Includes spec. $393.9 power. Give them a try for car 00 CAT # VCU-8 and hook -up sheet. or home applications. 00 each 411/ CAT # LCD -24 I 10 for $28.00 100 for $250.00 CAT # SK -31 each 1 urchase EXCESS INVENTORIES... Call, Write or Fax YOUR LIST. WRITE CALL, ORDER TOLL FREE 1 - -5432 FAX For A 800 -826 MAIL ORDERS TO: ALL ELECTRONICS CORP. FAX (818) 781 -2653 Page P.O. BOX 567 (818) 904 -0524 Free 64 VAN NUYS, CA 91408-0567 INFO Orders CATALOG. Minimum Order $10.00 All Orders Can Be Charged to Visa, Mastercard or Discover Checks and Money NO C.O.D Accepted by Mail Orders Delivered in the State of California must include California State Sales Tax U.S.A. Hawaii, P.R. and OUCIvER Outside the Shipping and Handling $4.00 for the 48 Continental United States - ALL OTHERS including Alaska, Full Shipping Quantities Limited Prices Subject to change without notice. S2.00 postage. Canada Must Pay send 109 CIRCLE 28 ON FREE INFORMATION CARD

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covers all makes - . aide ( $69 ) - detailed, comprehensive, Plant Stim., Kirllan, morel All .tans for onl 529 t.p 0 times more into than competitor's' guides . (Do Se- ctal Pro WI below for up -to -date hardwaretoftware . UNDER ATTACK! Electromagnetic Interlerence and Electronic Weapon SPECIAL PROJECTS Attacks cause: Cancer, birth defects, and profound psy- e .es gn, .ul ., repair, mods y, maintain a-or consult s neurological, cardiovascular and immune project - electrical, on any device. system, process or systemsyste disorders) Destructive to people, animals, plants, optical, auto- electronic, computer, phone, mechanical, aqulpmenu Includes ACTUAL CASES OF EM Invention prototyping. ConlldenUallty guaranteed. motive. DN PEDPLE-Me electro Includes how to verifyeerie- fee (does not Describe and Include S25 pre -engineering and pinpoint EMI and electronic attack sources, and ope- in 7-10 da s. obit. ate ou . lime and cost estimates cillc countermeasures. $29. 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Slmp e 'owe u , versah e, menu -.oven r ar ames auto.) way to deleaL Na special aler lets you dial any quantity (up to 10K) or mix of locaV and automatic to install on your distributed software. system;. long distance numbers in any order, over any length of Compatible with all other copy -prevention time, whether busy or answered (your choice) and log Manual + Disk* $59. the times, commands and results to monitor, printer STEALTH TECHNOLOGY and -or disk Oulck -dial directory of up to 600 numbers. olice ra. ar s ascinabng t a so as error rates o 10- BUSY redial options. Direct modem command and con- he's a hero. 20%1 Every known error mode - stealth methodrat sod ma- AU Result Codes, Including VOICE and RINGING. ferial used fo minimize radar reflections tactic and Optional shell to terminal pro .ram upon CONNECT. brit strategy to fight unjust radar tickets (that Cost you menu or DOS for balchin.. 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www.americanradiohistory.comAmericanRadioHistory.Com 450 MHz SPECTRUM ANALYZER Adapted from Nov. '85 OST article by Al Helfrick K2BLA CHANNELS PE MARKET CENTER CABLEe. EOUIPM CLASSIFIEDS GU F Trie nationwide source Q4ÿ for catie TV equipment h* "BUY WHERE THE DEALERS BUY."

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Cable signals come in, but they don't go out! $29.95, + Smart Video Decoder $3.00 S &H. Visa /MC. ELECTROMAN, Box Battery Easy Connections 24474, New Orleans, LA 70184. (504) 482 -3017. EIIrlinaNalarrnlird A DESCRAMBLER SCHEMATICS REVEALED. Charger C0Py ^Y MC* 2 Year Warm* powerful guide to descrambling schemes. $10.00. RC Pkrga Bx,tuded 30 Dy Many Back Gunnies 24474, New JUN 87 OST Visa /MC. ELECTROMAN, Box EIECTROAICS Orleans, LA 70184. (504) 482 -3017. BY WARREN DION N1BBH V18411, ECA C.o.0. 1-500-676-6342 100a'a CABLE UNSCRAMBLED. Everything you want FOR GEL -CELLS or LEAD ACID BATTERIES. to know about cable, but are afraid to ask, $10.00. Features: Precision temperature tracking voltage 21 S. Main St, Winter Garden, FL 34787 Visa /MC. ELECTROMAN, Box 24474, New reference & three mode charging sequence. 1 user Orleans, LA 70184. (504) 482 -3017. Standard kit is for 12V ea 112 or Amp, selectable. Can be connected to the battery UNIVERSAL DESCRAMBLER. 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www.americanradiohistory.comAmericanRadioHistory.Com USE PE MARKET CENTER CLASSIFIEDS READ BY 87,877 BUYERS OF ELECTRONIC EQUIPMENT ACCESSORIES AND PARTS

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

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

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

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

Ad No 1 -Total words x $1.00 per word =$ 13- $15.00 14- $15.00 15 - $15.00 16 - $16.00 All Caps words x .20 per word= $ 17- $17.00 18 - $18.00 19 - $19.00 20 - $20.00 Bold words x .20 per word =$

Bold Cap words x .40 per word =$ 21 - $21.00 22 - $22.00 23 - $23.00 24 - $24.00

TOTAL COST OF AD No. 1 $

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,2711+JiElO TI298.7625T F27fío ( Weather Stations COMMUNICATIONS -. r E ©( m ® E7 Now you can be your own weather reporter with the Davis Weather b Monitor D. Our top-of-the-line weather station combines the most advanced ELECTRONICS INC. SS b weather monitoring technologies available into one incredible package. ` ó® Glance at the display, and see wind direction and wind speed on the compass Emergency Operations Center rose. Check the barometric trend arrow to see if the pressure is rising or falling. Push a button, and read indoor and outdoor temperature, wind chill, Bearcat 8500XLT -K Radio Scanner humidity and barometric pressure. Our package deal includes the ultra high resolution I /100 Inch rain collector part 7852-K, and the external Mfg. suggested list price $689.95/CE price $368.95 26th Anniversary Special temperature/humidity sensor, part 07859-K. The package deal is order 500 Channels 20 banks Alphanumeric display #DAVI -K for $479.95 plus $15.00 shipping. If you have a personal computer, Turbo Scan %TO Control Priority channels when you order the optional Weatherlink computer software for $139.95, you'll have a powerful computerized weather station at an Auto Store Auto Recording Reception counter incredible price. For the IBM PC or equivalent order part 786211 Apple ;Save $30.001 Frequency step resolution 5, 12.5, 25 & 50 KHz. Mac Plus or higher including PowerBook, order part number 7866 -K. The Weather Monitor /I (7440-X) comes Size: 10-1/2" Wide x 7.1/2' Deep x 3 -3/8" High Ion Bearcat, 8500XLT scanner, complete with anemometer with 40 feet Frequency Coverage: of cable, external temperature sensor or RELM WHS1 50 VHF transceiver. 25.000 28.995 MHz. (AM), 29.000 - 54.000 MHz. (NFM), with 2S feet of cable, Janette'', box with 54.000. 71.995 MHz. (WFM), 72.000 - 75.995 MHz. (NFM), 8 feet of cable, ACpower adapter, II our 26th anniversary with special savings on your. 76.000 - 107.995 MHz. (WFM), 108.000 - 136.995 MHz. (AM) detailed instruction booklet one choice of a new Bearcat 8500XLT scanner or RELM WHS 150 and 137.000 - 173.995 MHz. (NFM), 174.000 - 215.995 MHz. (WFM), year limitedfactory warranty. 1 VHF five watt transceiver. This coupon must be included with 216.000 - 224.995 MHz. (NFM), 225.000 - 399.995 MHz. (AM) your prepaid order. Offer valid only on orders mailed directly to Davis Weather Monitor 117440-K $334.95 400.000 - MHz. (NFM), - MHz. (WFM) ICommunications Electronics Inc., P.O. Box 1045 -Dept. PE0195, I 511.995 512.000 549.995 Davis Weather Wizard III 7425 -K $154.95 Ann Arbor, Michigan 48106 U.S.A. Coupon expires January 31, 760.000 - 823.9875 MHz (NFM), 849.0125 - 868.9875 MHz (NFM) Davis Remote Display Unit 7815 -K $84.95 1995. Limit one coupon per item. Coupon may be photocopied.. 894.0125 - 1,300.000 MHz. (NFM). Davis Rain Collector II 0.01" 7852 -K $59.95 1 Coupon may not be used in conjunction with any other offer. The new Bearcat 8500XLT gives you pure scanning satisfaction Davis Rain Collector II 0.2 mm 7852M -K $59.95 External Temperature/Humidity Sensor 7859-K CrCredit cards are excluded from this offer. Void where prohibited. with $99.95 -mot_ NM ME M M MO ME MO amazing features like Turbo Scan. This lightning-fast tech- Davis Anemometer Mast Mount 7890-K $15.95 M nology featuring a triple conversion RF system, enables Uniden's Weatherlink Software for IBM PC- Version 3.0 7862 -K $139.95 best scanner to scan and search up to 100 channels per second. Weatherlink Software for Apple- Version 3.0 7866 -K $ 139.95 4-Conductor Because the frequency coverage is to large, a very fast scanning 40' 12.2 m) extension cable 7876 -K $ 17.95 6-Conductor 40' 12,2 m) extension cable 7878 -K $21.95 Bearcat Scanners system is essential to keep up with the action. Other features 8-Conductor 25' 7.6 m) unction box cable 7880 -K $14.95 indude VF0 Control - (Variable Frequency Oscillator) which 8- Conductor 50' 15 2 m unction box cable 7881-K $24.95 Bearcat 200XLT -K Radio Scanner allows you to adjust the large rotary tuner to select the desired 8-Conductor 100 S(3Ò.5junction m) box cable 7882 -K $44.95 frequency or channel. Counter Display - Lets you count and Modem Adaptor 2 -pin for communications port 7870-K $9.95 Mfg. suggested list price $509.95/CE price $198.95 Car/Boat/RV Lighter Cord 7873 -K $9.95 record each channel while scanning. Auto Store - Automati- 2400 baud modem for Weatherlink MEXT-K 339.95 200 Channels 10 Banks Cellular Modifiable cally stores all active frequencies within the specified bank(s). Weatherlulk language disks: Frantalse, Deutsche, Ital.a, F.paeola 7863432495 Heavy duty carry case Illuminated LCD Search Auto Recording - This feature lets you record channel activity Size: 2 -3/4" Wide x 1 -1/4" Deep x 7 -1/2" High from the scanner onto a tape recorder. You can even get an Frequency Coverage: 29000 -54.000,118.000-174.00,406.000.512.000, optional CTCSS Tone Board (Continuous Tone Control Squelch Other neat stuff System) which allows the squelch to be broken during scanning 806.000 - 823.9875, 849.0125 - 868.9875, 894.0125 - 956.0000 MHz Gnudwg Stoat 7064 porubk ,0grtwave receiver with 512 memory a AC adapter 11389.95 only when a correct CTCSS tone is received. 20 banks - Each Gnr dig Yrin Boy 4061 digital portable shortwave rttWer - 40 memory paten f 199.95 Recently, the FCC amended Parts 2 15 and of its rules bank contains 25 channels, useful for storing similar frequencies Gea die Yacht Boy 256[ portable shortwave receiver ...... _._...... 7139.95 Sutgean A1S8000 portable 20 memory shortwave nether _ ...... ____...._...... 169.95 to prohibit the manufacture and importation of scan- in order to maintain faster scanning cycles. For maximum Sent/can A15803A-[ portable shortwave receiver w /AC adapter -9 memory prewa$148.95 Saner. Anset -[ portable 45 memory shortwave receive r ...... _...... __._....._ ning radios capable of intercepting the 800 MHz. scanning enjoyment, order the following optional accessories: 7159.95 PS001 Cigarette lighter power cord for temporary operation Sang= ATSat& 4 portable shortwave weber with anon recorder ....__...... 72119.95 cellular telephone service. The Electronics Communi- Uniden ER92a4 900 aaa 2 are mrdkss phone ...._...... _..___.._.._._.__..._....._ $289.95 from your vehicle's cigarette lighter S14.95; PS002 DC power Braden FX/9100.1 900 aas 1 hoe cordless phone ._...... _...... _...... _ $269.95 Cube CP9124 900 mix spread spectrum medien phone ...... _...... $249.95 cations Privacy Act prohibits the intentional intercep- cord - enables permanent operation from your vehicle's fuse box Bogen 7120064 DOA Moline advanced vole mall system s enswedng machine $279.95 tion of cellular telephone transmissions. Supplies of $ 14.95; MB001 Mobile mounting bracket S 14.95; BC005 CTCSS Bogen 1100184 memory expansion module, doubles recording time to 36 minute.. 179.95 Tone Board $54.95; EX711 External speaker with mounting FANS Pt61P4 60 name /number taller m, .wanted call Mocker, automa& paging 7149.95 SNI m206[ Bonner name/numbea taller m, W aka, forward to machine ...... _..._ $89.95 scanners that are capable of being easily modified to & 10 feet of plug The bracket cable with attached $19.95. ICON GP224 handheld global poshloNng mite (GPS) _...... _.._...... _...... _._ $599.95 receive full 800 MHz. coverage such as the Bearcat BC8500XLT comes with AC adapter, telescopic antenna, owner's W12u6[ wearier radio with National Weather Service storm Jeri ...... _. $59.95 manual and one year limited warranty from Uniden. Order your 1n WNS1504 MP handheld 5 Wan, 16 channel transalver ...... _...._...... $339.95 200XLT are in critically short supply. Today could be 171111}1256/04 VHF 25 watt, t6 channel synthesized transceiver ...... _...... _... $289.95 BC8500XLT from Communications Electronics Inc. today. [anger [02950[ 25 watt 10 toter ham radio transceiver ...... - - - -.- $239.95 your last chance to buy your Bearcat 200XLT scanner. tanger 102970[ la wan to mete ham radio enmabv ...... _....._.__..._.. $569.95 UNden i2891o0ss4 super W1debW caner /$ache Detector...... __._-_._ $t59.95 Signal intelligence experts, public safety agendes and sr24 asp P.pr CD arum tin 18th PC by ndonne Mapping $299.95 CB /GMRS Radios ricrol N.nc.e ce [om lox ®N PC by Bnrkmuter Pu000ing.....__...___.._... 19995 people with inquiring minds that want to know, 051t4 VHF scanner/VW n.ns.NW5 antenna PL59 connector ..._...___.__. $29.95 ANIMNBNG[ magnet mount yammer ante... wi BNC romrettor ____....__._- $29.95 depend on the Bearcat 200XLT handheld scanner to ANT/0040U magnet mount scan /AMU WMotoroIa plug...... __.__...... _._..._ - $29.95 a,Cobra ANfMNPL[ magnet noun, fan .knit with PUSS conned. ...._._...._ ...... $29.95 intercept just about any radio transmission. You can ANISGBNc4 gin, mount saner antenna with BNC eonnecta ...... _ ...... 729.95 29LTU WX CLASSIC ANISGA T.I lass mount wanner antenna with Motomia lack $2995 also program frequencies such as police, fire, emer- Cd RADIO gency, race cars, marine, weather, and other broad- [Buy confidence) casts into 10 banks of 20 channels each. with A modification sheet with instructions to restore full It's easy to order from CEI. Mail orders to: Communications Electronics Inc., Emergency Operations Center, P.O. Box 1045, 800 MHz. coverage for our Bearcat 200XLT or Bearcat Ann Arbor, Michigan 48106 USA. Add $ 15.00 per radio or 2500XLT may be ordered for $8.00. To order your telephone product for U.P.S. ground shipping and handling in A National Weather Service (NWS) receiver with auto- 1 the continental U.S.A unless otherwise stated. Add $8.00 Bearcat scanner, call -800- USA -SCAN. matic emergency broadcast activation has been added to the shipping for all accessories and publications. Add $8.00 ship- Other Bearcat Scanners legendary Cobra 29 CB radio. The integrated NWS receiver ping per antenna For Canada, Puerto Rico, Hawaii, Alaska, P.O. in the Cobra 29LTDWX will automatically activate to Box, or APO/FPO delivery, shipping charges are two times -K Bearcat 8500XLT base /mobile$368.95 receive emergency announcements about severe weather continental U.S. rates. Michigan residents add state sales tax. NEW Bearcat 3000XLT -K handheld`$379.95 and travel conditions. A special tone-alert signal broadcast No COD's. No returns or exchanges after 31 days. 10% surcharge by the NWS activates the weather receiver and overrides any for net 10 billing to qualified accounts. All sales are Bearcat 890XLT -K base/mobile $228.95 subject to availability, acceptance and verification. Prices, CB radio reception for monitoring the warning message. terms and specifications are subject to change without notice. Bearcat 855XLT -K base $148.95 Cobra 29LTDWX -K CB/Weather Alert.. $129.95 We welcome your Discover, Visa, American Express or Bearcat 760XLT -K base/mobile $198.95 Cobra 2000GTL -K SSB Deluxe CB Base$389.95 MasterCard. Call 1-800-USA-SCAN to order toll-free. Call 313- 996.8888 if outside the U.S.A. FAX anytime, dial 313-663-8888. Bearcat 700A -K info mobile $148.95 Cobra HH40 -K CB 40 ch. Handheld $99.95 For technical assistance to solve your communications problem, call the Communications Electronics technical Bearcat -K Uniden GMR100 -K GMRS Handheld.....$159.95 560XLA base /mobile $83.95 support hotline for $2.00 per minute at 1- 900 -555 -SCAN. Uniden WASHINGTON -K SSB CB Base . $189.95 Saner nOnibutkn Center and ® logos are tndeurts M Commmin taus 7kcrooks Inc Bearcat 220XLT -K handheld $228.95 Sole data 12/1/94 1/31/95 AD .11I S94Gr.N Copyrrgbt o 1995 Communications nomeux tar Uniden GRANTXL -K SSB CB Mobile $139.95 New product - available 60 -90 days after receipt of order. Bearcat 200XLT -K handheld $198.95 Uniden PR0538W -K CB & Weather $59.95 Bearcat 178XLT-K base/WX alert $133.95 For credit card orders call

Sportcat 150 -K handheld $178.95 111111111t Bearcat 148XLT-K base/WX alert $88.95 1-800-USA-SCAN Communications Electronics Inc. Bearcat 120XLT -K handheld $148.95 O.- P.O. Box 1045, Ann Arbor, Michigan 48106-1045 U.S.A. bra, Bearcat BCT2 -K info mobile $138.95 cs 2000 GTL For information call 313- 996.8888 or FAX 313-663-8888 CIRCLE 166 ON FREE INFORMATION CARD

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Easy installation. Installing the Smart Alarm requires no fumbling with wires. Special Plug -In Connectors let you install the Smart Alarm without a single wire -cutter! Simply unplug the headlight connector, plug in the Smart Alarm connector, and then plug the headlight connector to the Smart Alarm. Connect the Smart Alarm to the battery cable with the special clip. In minutes, you and your car can enjoy complete 24 -(tour protection. Away from your car, you'll feel safer knowing that your car is protected! Near your car, you'll feel safer knowing that you are protected!

All you do is give up your car and activate the delayed panic alarm. When the assailant has reached a safe distance and is no longer a threat to you, a deafening 120dB siren and flashing p.m. lights will force him to flee your car, letting -94 8:07 1 -6 and two you recover it safely. Mother Situation: lot Vehicle protection. Smart Alarm's cur- in mall parking children rent sensor triggers the siren if the trunk or any of the doors are opened while the alarm is armed. To supplement the current sensor, a shock Compare sensor triggers the siren when it de- Other car Smart alarms Alarm The first alarm system designed to tects a blow to your car. Together, these sensors provide protect you as well as your car... your car with blan- ket protection. to Revolutionary new vehicle security system is the first of its kind An adjustable 100 fest focus on the safety of the vehicle driver as well as the vehicle itself shock sensor prevents the siren By Charles Anton from being trig- Rangs. Other gered, eliminating car alarms Oulu Do you wonder why car alarms have sonal protection with the panic alarm, that's just false alarms. You work up to loi r countless features to protect your car, the beginning of the Smart Alarm. In addition feet. All Smart t can also adjust the 400 feet but nothing to protect you? After all, to the panic alarm, the Smart Alarm also has a Alarm features shock sensor and work up to 400 what's more important car finder feature. You'll the siren with your feet away. your car or the safety of never again have to remote control at you and your family? What makes Smart Alarm better? wander around a dark any time you Now there is a car and dangerous parking choose. The siren's tone and volume can be ad- alarm that will protect you Range. Most car alarm features only lot searching for your justed to six separate tones. As a result, you'll car. You will be able to and your family. It is the work up to 100 feet away -all Smart never confuse it with any other alarm. You can know where your car is first of its kind to focus Alarm features work up to 400 feet away. also customize the siren, making it louder in on the safety of the ve- from anywhere within noisy neighborhoods and quieter in more hicle owner as well as Panic button. Smart Alarm lets you 400 feet by flashing its peaceful neighborhoods. the vehicle itself. call for help or scare away potential trou- lights and briefly sound- Risk free home trial. With the Smart blemakers by controlling a piercing alarm ing the siren. You can Protect yourself. It Alarm, you get a complete "No Questions activate and deactivate all begins with the panic and your car's headlights. Asked" 30 -day money -back guarantee. If it's your car's headlights by button. Imagine you're not everything we say, just return it for a full Car finder. Your car will be able to remote control to light walking to your car at is a let you know where it is by flashing it's refund. The Smart Alarm also backed by night and a person ap- your way in a dark two -year warranty. Your order will be shipped lights and briefly sounding the siren. driveway or parking lot. proaches. Pushing the UPS in seven to ten working days. panic button on your Carjacking. Its delayed panic alarm Carjacking. The transmitter lets your car allows you to safely prevent theft of your Smart Alarm also ad- The Smart Alarm Car Alarm $99 $9 S &H come alive with a car when confronted by a carjacker. dresses a growing haz- shrieking siren and ard for today's mo- Please mention promotional code 483-PL1108. Easy installation. Other car alarms flashing headlights. torists -carjacking. It's For fastest service call toll -free 24 hours a day While the panic alarms are complicated or cost hundreds of dol- alarming how often of other vehicle security lars to install. Smart Alarm is inexpen- drivers are hurt in their 800 -992 -2966 systems have a range of sive, and you can install cars because they re- ERIWN EXPRESS 100 feet, the Smart it in just minutes. fuse to give them up to _ Alarm's panic alarm lets carjackers. Because of To order by mail, send check or money order for the you call for help or scare Smart Alarn- its anti -carjacking de- total amount including S&H (VA residents add 4.5% Or charge it to your credit card, enclosing away potential attackers is the first car vice, the Smart Alarm sales tax.) your account number and expiration date. from up to 400 feet! alarm that will allows you to safely re- protect you tain your car when con- ri Exclusive feature. and your -agia= Unlike other car alarm family. fronted by a carjacker. INDUSTRIES systems that begin and 0 This is made possible by 2820 Waterford Lake Drive Suite 106 end their focus on per- a delayed panic alarm. Midlothian, Virginia 23113

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