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FEBRUARY 1985 $1.95 CANADA $2.50

THE MAGAZINE FOR ELECTRONICS & COMPUTER ENTHUSIASTS

Minds In Home Salell te TV Receiving (p. 32)

El %That's New in Home TV Experimenting with Satellite Installations Analog Comparators Si Creating Circuits II How to Put New Life into from Scratch Apple Ile ROM Monitors

Zenith's Camcorder For Home Video Movies (p. 15) Build A "Surf our d- S)und" Stereo Accessory (p. 55)

02 Pius: Evaluating Zenith's VM6000 VHS Video Camcorder and San urs AV77 Audio/Video Processor-Controller Shortwave 0 Listening News Don Lancaster's "Hardware Hacker" Questions/ Answers Technical Book Reviews Latest Electronic/Computer 74820 08559 Happenings ... and more.

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100 MHz dual A/B sweep selec- time base scope. tion. Calibrated Easy-to -read CRT; Wide range verti- A sweeps from bright, full -sized cal sensitivity. Two 100 MHz, 50 ns /div to 8x10 cm; 14 kv Choose from high sensitivity 0.5 s /div; B sweeps accelerating 2 mV /div (lx channels. 3.5 ns from 50 ns /div B trigger slope potential complete probe) to 50 V /div risetime; dc to to 50 ms /div; vari- and level. Use B with BEAM FIND, (10x probe); 100 MHz band- able control for up Dual time base trigger level to separate A/B color -keyed for lx width from 5 V/div to 2.5 to 1 reduc- measurements. select B- triggered dual intensity and 10x probes; to 5 mV /div; tion and 10x Select either A or or run -after -delay controls, FOCUS variable control extended sen- magnification for B sweeps, or both modes; use B and TRACE increases scale sitivity of 2 mV /div sweeps to alternately with A TRIGGER SLOPE ROTATION. factor by 2.5 to 1. at 90 MHz. 5 ns /div. intensified by B. to select transitions.

Our direct order line gets have the bandwidth for digital you the industry's leading and analog circuits. The sensitivity price/performance portables... for low signal measurements. The and fast answers from experts! sweep speeds for fast logic fami- manual, two 10X probes, 15 -day The 60 MHz single time base delay lies. And delayed sweep for fast, return policy and worldwide ser- 2213A, the 60 MHz dual time base accurate timing measurements. vice backup. 2215A and the 100 MHz dual time All scopes are UL Listed and CSA base 2235 offer unprecedented approved. Order toll free: reliability and affordability, plus the You can order, or obtain 1 -800- 426 -2200, industry's first 3 -year warranty* literature, through the Tek on labor and parts, CRT included. National Marketing Center. Tech- Ask for Rick. In The cost: just $1200 for the nical personnel, expert in scope Oregon, call collect 2213A, $1450 for the 2215A, applications, will answer your (503) 627 -9000. $1650 for the 2235.t Even at questions and expedite delivery. Or write Tektronix, Inc. these low prices, there's no Direct orders include comprehen- P.O. Box 500, Delivery Station Y6 -088 scrimping on performance. You sive 3 -year warranty *, operator's Beaverton, OR 97077

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You say you're already trained in electronics Put Professional Knowledge and a but that you're not making enough money? ?? Well then, maybe you don't have an accredited COLLEGE DEGREE bachelor's degree to prove that your education in your Electronics Career through is up to snuff! Check out the Grantham Inde- pendent -Study B. S. Degree Program. It could Independent Home Study make a dollars and sense difference in your electronics career. Study materials, carefully written by the Grantham staff for independent study home, Grantham offers this program, complete but College at are by Your without laboratory, supplied the College. technical questions to electronics technicians related to these materials and the lesson tests are whose objectives are to upgrade their level of promptly answered by the Grantham home -study technical employment. Since the field of elec- teaching staff. tronics is so enormous, opportunity for ad- vancement is always present. Promotions and Recognition and Quality Assurance natural turnover make desirable positions Grantham College of Engineering is accredited by available to the man who is ready to move up. the Accrediting Commission of the National Home Study Council, as a degree -granting institution. Grantham College of Engineering

10570 Humbolt Street All lessons and other study materials, as well as communications between the college and students, are in the Los Alamitos, California, 90720 English language. However, we have students in many foreign countries; about 80% of our students live in the United States of America. r for 1 Grantham College of Engineering M -2 -85 FREE 10570 Humbolt Street, Los Alamitos, CA 90720 Booklet Please mail me your free catalog This free booklet CLIP which explains your B.S. Degree independent -study program. explains the COUPON i Grantham B.S. and mail in I Name Age Degree Program, envelope or offered by inde- paste on Address pendent study to postal those who work card. City State Zip in electronics. L

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Type Positions Cat. No. Each 20% Tolerance Type Cat. No. Each IC PCB Spacing Solder Sub-D Male 9 276-1537 1.99 2N1305 PNP 276-2007 1.19 NPN 276-2009 .79 Solder Sub -D Female 9 276-1538 2.49 MPS2222A pF WVDC Cat. No. Each PN2484 NPN 276-2010 .89 Hood for Above 9 276-1539 1.99 0.1 35 272 -1432 .49 MPS3904 NPN 276-2016 .69 Solder Sub-D Male 15 276-1527 2.49 0.47 35 272-1433 .49 TIP31 NPN 276-2017 .99 Solder Sub -D Female 15 276-1528 3.49 TIP3055 NPN 276-2020 1.59 1.0 35 -1434 .49 Hood for Above 15 276-1529 1.99 272 MPS2907 PNP 276-2023 .79 2.2 35 272 -1435 .59 MJE34 PNP 276-2027 1.49 Solder Sub -D Male 25 276-1547 2.99 10 16 272 -1436 .69 NPN 276-2030 99 Solder Sub -D Female 25 276-1548 3.99 2N3053 22 16 272 -1437 .79 MPS3638 PNP 276-2032 .79 25 276 1.99 Hood for Above -1549 TIP120 NPN 276-2068 1.29 Solderless Sub-D Male 25 276-1559 4.99 2N3055 NPN 276-2041 1.99 Solderless Sub -D Fern. 25 276-1565 4.99 Monolithic Ceramic MJ2955 PNP 276-2043 2.19 Printer Connector 36 276-1534 6.99 2N4401 NPN 276-2058 .59 Cable Socket 34 276-1525 3.19 Capacitors MPSA06 NPN 276-2059 .59 MPSA13 NPN 276-2060 .59 Epoxy Dipped 50 WVDC MPSA42 NPN 276-2061 .69 2SC945 NPN 276-2051 .79 1/4 Watt, 5% Resistors 2N3819 N-FET 276-2035 .99 _- Temperature MPF102 N-FET 276-2062 .99 Pkg. of 5 Value Coefficient Cat. No. Each IRF511 V-FET 276-2072 2.59 39c IRFD1Z3 V-FET 276-2073 1.49 100 pF NPO 272 -152 .69 2SC1308 NPN 276-2055 7.95 Ohms Cat. No. 470 pF NPO 272 -153 .69 10 271 -1301 Ohms Cat. No. 1000 pF Z5U 272 -154 .69 100 271 -1311 10k 271 -1335 4700 pF Z5U 272 -155 .69 150 271 -1312 15k 271 -1337 .01 pF Z5U 272 -156 .69 RS -232C Line Driver, Receiver 220 271 -1313 22k 271 -1339 .047 µF Z5U 272 -157 .69 270 271 -1314 27k 271 -1340 .1 IF Z5U 272 -158 .79 330 271 -1315 33k 271 -1341 Type Cat. No. Each 470 271 -1317 47k 271 -1342 MC1488 Driver 276-2520 1.79 1k 271 -1321 68k 271 -1345 Mini SPDT Relays MC1489 Receiver 276-2521 1.79 1.8k 271 -1324 100k 271 -1347 2.2k 271 -1325 220k 271 -1350 Only 1 x 11/16x3/4 ". Typical 3.3k 271 -1328 470k 271 -1354 drain 12 mA -ideal for battery- 4.7k 271 -1330 1 meg 271 -1356 CMOS and Bipolar Timers powered circuits. Contacts: 1 6.8k 271 -1333 10 meg 271 -1365 amp at 125VAC. TLC555. New CMOS design with very low power 6 -9 VDC Coil. 275 -004 ..2.99 consumption -typically one milliwatt with 5 VDC supply. 12 VDC Coil. 275 -003...2.99 Same pinout as 555 but works with smaller, less expensive 4000- Series capacitors. 276 -1718 1 59 CMOS ICs Bipolar. Resettable timing from one .second to one hour. With Pin -Out and Specs Wire Wrapping DIP Sockets Type DIP Cat. No Each accept 3 levels of wrap. Type Cat. No. Each Square 0.25" posts 555 (Single) 8 -pin 276 -1723 1.19 4001 276 -2401 .99 Pins Cat. No. Pkg. of 2 556 (Dual) 14 -pin 276 -1728 1.49 4011 276-2411 .99 8 276 -1988 1.19 4013 276-2413 1.19 14 276 -1993 1.29 4017 276-2417 1.49 16 276 -1994 1.39 Dictionary of Microcomputer 4049 276-2449 1.19 4066 276-2466 1.19 Terms Solder DIP Sockets NEW! TTL Digital ICs Type Cat. No. Price Defines over 1200 modern day microcomputer terms 8-Pin 276-1995 2/596 With Pin -Out and Specs 14 -Pin 276 -1999 2/896 with clear and concise 16 -Pin 276- 1998 2/896 descriptions. Large, easy - Type Cat. No. Each to -read typeface. Over 100 18 -Pin 276-1992 .49 illustrations. Special up- 7400 276 -1801 .89 20 -Pin 276-1991 .59 front section contains over 7404 276 -1802 .99 24 -Pin 276-1989 .79 200 common abbreviations, 7408 276-1822 1.29 28 -Pin 276 -1997 .89 acronyms and special symbols. 96 pages. 7447 276-1805 1.59 40 -Pin 276 -1996 .99 62 -1392 2 79 7490 276-1808 1.09 Continuity Tester TV RF Modulator Power Supply MOV Transient Protectors Chassis Chassis Chassis

Power Diss. Cat. No. Each 600 mW 276 -570 1.59 1 watt 276 -568 1.69

Fast -Acting 5x20 mm Fuses SPECIAL SPECIAL SPECIAL Pkg. of 2 890 495 PURCHASE 195 PURCHASE 495 PURCHASE Amps Cat. No. Amps Cat. No. Circuit continuity produces a war - Selectable channel 3/4 output. 5-pin Our big buying power brings you a 0.315 270-1249 2 270 -1244 bling tone. Many possible uses in- DIN plug accepts video, audio and compact switching power supply for 1/2 270-1241 2.5 270 -1245 cluding security alarms, capaci- 12 VDC power inputs. On /off switch an incredibly low 446 a watt! Input: more. Operates with built -in TV antenna/modulator 18 VAC (use our #273 -1515 trans- 3/4 270-1242 3 270 -1246 tor /diode checker, from 9V transistor battery. Great ex- switching. Auto shutdown circuit in former). Outputs: 12 VDC at 400 mA, 1 270-1250 4 270 -1247 perimeter's item at a bargain price. case of signal input overload. +5 VDC at 1.1 amp and -5 VDC at 1.5 270-1243 5 270 -1248 277 -1014 1 95 277 -1015 4 95 200 mA. 277 -1016 4 95

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EDITORIAL STAFF Art Salsberg FigillmoDERN Editor -in -Chief Alexander W. Burawa ICS Managing Editor THE MAGAZINE FOR ELECTRONICS & COMPUTER ENTHUSIASTS Dorothy Kehrwieder Production Manager FEBRUARY 1985 VOLUME 1, NUMBER 5 Elizabeth Ryan Art Director FEATURES Barbara Scully Artist Pat Le Blanc Richard Kishanuk 22 Electronic Automotive Anti -Theft Alarms Phototypographers A look at the newest offerings and more. Hal Keith By Ron Cogan Illustrator 32 Home Satellite TV For 1985 And Beyond Larry Mulvehill Gleanings from the Fall 1984 Space /STTI show Photographer in Nashville. By Stan Prentiss Leonard Feldman, Glenn Hauser, 38 Upgrading Apple IIe's ROM Monitor: Forrest Mims III, Stan Prentiss, 22 Charles Rubenstein, Don Lancaster Part I Contributing Editors How to regain full control of your Apple IIe computer. By Don Lancaster BUSINESS STAFF Richard A. Ross 46 Circuit Design From Scratch No. 2 Publisher Hands -on approach to designing circuits, plus a Art Salsberg car anti -theft alarm you build. By Jules H. Gilder Associate Publisher Dorothy Kehrwieder 55 "Surround Sound" Enhancer General Manager Accessory recovers ambience information from recordings and adds delay to provide realistic sound. Anthony C. Sparacino SOLDER SECOND Newsstand Sales Director GREEN WIRE TO By John H. Roberts SOCKET END OF Arlene Caggiano PIM 20. Accounting Cheryl Chomicki 38 Subscriber Services PRODUCT EVALUATIONS SALES OFFICES Modern Electronics 76 North Broadway 12 Sansui AV -77 Processor -Controller Hicksville, NY 11801 Audio plus video plus much more. By Len Feldman (516) 681-2976 Eastern Advertising Representative 15 Zenith VM6000 VHS Camcorder Paul McGinnis Company Meeting the 8 -mm threat. 60 East 42nd Street By Stan Prentiss New York, NY 10017 (212) 490-1021 Midwest Advertising Representative Market /Media Associates 32 DEPARTMENTS 435 Locust Road Wilmette, IL 60091 (312) 251 -2541 Ted Rickard 4 Editorial Western Advertising Representative Price Wars. By Art Salsberg JE Publishers Representatives 6855 Santa Monica Blvd., Suite 200 4 Letters Los Angeles, CA 90038 (213) 467 -2266 8 Modern Electronics News Jay Eisenberg, Director 10 New Products San Francisco: (415) 864 -3252 Denver: (303) 595 -4331 62 Electronics Notebook Offices: 76 North Broadway, Hicksville, NY 11801. Tel- Experimenting with the Analog Comparator ephone: (516) 681 -2922. Modern Electronics (ISSN 0748- By 9889) is published monthly by Modern Electronics, Inc. Forrest M. Mims III Application to mail at second class rates pending at Hicksville, NY and other points. Subscription prices 69 Communications (payable in US Dollars only): Domestic - one year $16.97, Shortwave -Station News And Listening Tips two years $31.00, three years $45.00; Canada /Mexico By Glenn Hauser -one year $19.00, two years $35.00, three years $51.00; Foreign - one year $21.00, two years $39.00, three years $57.00. Foreign Air Mail - one year $74.00, two years 72 Hardware Hacker $145.00, three years $216.00. Author answers technical questions from readers Entire contents copyright 1985 by Modern Electronics, By Don Lancaster Inc. Modern Electronics or Modern Electronics, Inc. as- sumes no responsibility for unsolicited manuscripts. Al- 80 Books low six weeks for delivery of first issue and for change of address. Printed in the United States of America. Postmaster: Please send change of address notice to 81 Literature Modern Electronics, Inc., 76 North Broadway, Hicks- ville, NY 11801. 99 Advertisers Index

February 1985 / MODERN ELECTRONICS / 3

www.americanradiohistory.com Illi/ EDITORIAL X711 Price Wars

Here it is, December, and the local mer- Moreover, the company offers a $500 col- toward the higher- memory unit. It costs chants in metropolitan New York are lege scholarship to purchasers who meet "only" $1000 to upgrade from a 128K -er. promoting electronic gear with a ferocity certain requirements: attending a four - IBM's 64K model has been supplanted by you cannot believe. Retail prices scream- year college, satisfactory grades, and a its 256K model, of course, and the coming out in newspapers are so low that any- $125 payout each year. (The mathematics pany is readying the latter's successor, the one with a credit card and a yearning for on this one eludes me.) Radio Shack, too, PC2. Tandy, in turn, has an advanced lap the good things in life must find this very has its specials, with its 64K Color Com- computer up its corporate sleeve, and difficult to resist. puter going for $199.95, a $60 reduction, recently rolled out an IBM -compatible With most goods inching up in price, plus $349.95 for the disk drive, and its lap desktopper that's priced substantially less electronic contrivances of all kinds are computer TRS -80 Model 100 for $399, than an IBM PC. wonderfully under -priced ... or are they? down from $799. Nonetheless, with the amount of units Let's take a look at personal comput- Apple Computer is also in the act. Its and software on the market for the older ers, as an example. IBM dropped a shoe $1295 128K -RAM Apple IIc, with built - models, they're all still good buys. Soft- this year when it cut selling prices of its in drive, has been advertised for as little as ware is the key. PC line, forcing others to do the same. $888 with rebate certificates toward op- Other consumer electronic bargains Maneuverings to make way for new mod- tions. The company's 128K Macintosh abound. Video cassette recorder prices els have driven prices down, too. And with built -in drive and 9 " hi -res monitor is have dropped considerably. Note, bloated warehouses with computers that down to $1695 from the opening price this though, that many of the low -cost offer- didn't move as briskly as manufacturers year of $2495. IBM's improved PCjr is ings are two -head machines; not the best, hoped they would called for "clear the now touted at $995 with 128K of RAM, a but not so bad if you're not a fuss -pot. decks" action. built -in drive, and a color monitor, to- Just so you know that you're giving up As a result of the foregoing, there are gether with a few hundred dollars of soft- something to get the bargain. even some price wars going on among ware, while I've seen a 64K IBM PC with Some "buys" are not really bargains, manufacturers. The Jack Trameil team's two drives promoted at $1695, with. the naturally. For example, cordless tele- move to Atari from Commodore has re- regular price noted as $2240. phones operating in the 1.7 MHz and 49.8 sulted in the Atari 800XL 64K -RAM Wow! MHz bands are being dumped due to a computer's price to drop from its orgini- These are, in truth, all bargains. Hid- variety of communication problems. The nal $199.95 to a manufacturer's suggest- den, though, are some churnings for new FCC -allocated frequency of 46 MHz ed $120. I've seen it advertised for as low thought. Will the Atari 800XL continue (and 49 MHz) are the ones to get if you as $99.95! And an accompanying 1050 along in 1985? Jack Trameil says, "Yes," want to roam and talk without a phone - disk drive at $149.95 from its original with a company spokesperson observing line tether; up to 1000 ft. away, that is. $299. That's about $250 for the system that it'll be producing 500,000 monthly So keep a wary eye on those bargains. (less printer). (sic) by mid -'85. Meanwhile, Atari is put- Many are indeed great buys. Just be sure Trameil's now -arch enemy, Commo- ting the final touches on new 8 -bit, 16-bit, you'll be able to live with the older models dore, is in at as low as $180 for its best- and 32 -bit computers. Commodore, too, for a few years ... and pocket the savings. selling Commodore -64 model and $250 is revving up new models. So are the for its disk drive, for a $430 rock -bottom others. Apple's 512K "Fat Mac" will cut package. Coleco's ADAM has been pro- into its original model's sales, with more moted for as little as $489 with a printer. meaningful business software geared ldatAr

IIi// LETTERS Illlb

Travellers Beware tent tuner, would receive several Japa- the U.S. Armed Forces Television Service nese vhf frequencies, but not the Japa- has low-power TV stations using NTSC nese vhf frequencies allotted to the FM in those locations. (AFRTS also uses I am writing about "Countries Using radio band in the U.S. uhf frequencies are NTSC in Germany, and perhaps other U.S. Video Standard" (October, 1984 compatible with the U.S. (2) I realize tha places.) issue). Before lugging a TV to another the list of countries was not specifically Wayne Hedenschoug country, check the radio section of the labeled as a list of countries also using the Springfield, IL World Radio TV Handbook to make sure same electric current as the U.S., but it electric current is compatible with the would be easy to get that impression. In U.S., and the TV section of the WRTVH St. Kitts, for example, current is 220 Fan Letter to make sure the video system and TV volts, and plugs and outlets are not com- Congratulations. I too was a subscriber broadcast bands are compatible. The patible with the U.S., necessitating a uni- to Popular Electronics since it's begin- compatibility problem is more com- versal current and plug converter, or a ning. After they changed to a computer plicated than indicated: (1) Japan uses battery- operated TV. I think a few other magazine I terminated my subscription. NTSC, but most of its vhf frequencies are countries listed in the item also use dif- As a token of faith in you I am enclosing a different than those used in the U.S. A ferent electric current than the U.S. (3) check for my subscription. TV with a continuously -variable vhf Greenland and the Azores do not use Marvin L. Fudalla tuner, as opposed to a "click- stop" de- NTSC or U.S. electric current; however, Pompano Beach, FL

4 / MODERN ELECTRONICS / February 1985

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With your first -- - experience. module, you the way up to tomorrow's get this latest VLSI (Very Large solder less 15 -Day No -Risk Trial breadboarding Scale Integrated) circuitry. system. You'll To order your first module with- use it through- In your very first module, you'll out risk, send the postage-paid card out the series to build elec- use integrated circuits to build a digital today. Examine it for 15 days under tronic circuits and bring oscillator, verifying its operation with the terms of the order form and see concepts a light emitting diode (LED). You'll to life. how the Contemporary Electronics learn to identify passive and active Series gets you into today's electronics. components, understand concepts If card has been used, write us for common to all electronic circuits. experience is reinforced through ordering information. interaction with vividly illustrated For Anyone Interested in Electronics text, audio cassettes, and actual The Contemporary Electronics I ' McGraw -Hill electronic experiments. Indexed Series is designed for anyone from Continuing Education Center Wisconsin Ave. binders preserve backup material, hobbyist to professional. It's for you 111 4A 3939 notes, and tapes for convenient if you're looking for new fields of H ill Washington, D.C. 20016 referral. interest...if you're a teacher who

February 1985 / MODERN ELECTRONICS / 7

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SOLDERING TIPS ON VIDEO TAPE. New video cassettes give pointers on soldering methods and equipment used to replace integrated circuits and other electronic devices. The full -color tapes, available from the Consumer Electronics Group of the Electronic Industries Association (EIA), come in both VHS and Beta tape formats. A 45- minute version targeted for electronic instructors costs $20, while a 15- minute tape for electronic technicians is priced at $15. To obtain one, send check or money order payable to Electronic Industries Association. Adress: EIA /Consumer Electronics Group, Dept. PS, P.O. Box 19100, Washington, DC 20036.

"GETTING STARTED" COMPUTER PROGRAM. Computer and software makers continue striving to make their wares as easy to use as possible, though the mark is more often missed than hit. A new software package from Texas In- struments, its "Getting Started" program, is a tutorial diskette and instruction booklet that starts off with unpacking a TI Professional Computer, setting up the system, and keyboard lessons. Additionally, it teaches users how to use TI's NaturalLink® products which accesses standard software using plain English commands. Continually expanding its product lines, TI recently announced four new font modules for its Model 855 and 865 printers, allowing them to print Bar Code 3 of 9, OCR A, Greek /Math scientific symbols and Script.

STEREO COMMERCIALS. Memorex is producing an audio tape TV commercial in stereo, marking the first time that stereophonic sound has been used for this purpose. Most people are not yet plugged into TV's stereo sound (nor are broadcasters), but the number will surely grow.

CLOSING THE QUARTZ -CLOCK SECONDS GAP. The Swiss, who ruled the watch industry when clock movements were mechanical, are trying to do the same in the electronic (quartz movement) watch field. An advanced technology is said to have been developed in Switzerland that increases accuracy to five times better than conventional quartz movements can attain, and adds longer battery life and no- adjustment requirement. The trick is said to be accomplished with a CMOS IC that has thousands of transistor equivalents and a nonvolatile memory, and an oscillator "thermostat." Accuracy is claimed to be +60 seconds for five -years.

VCR SALES SURGE. According to the EIA, home video cassette recorder sales to retailers increased more than 80% in the first ten months of 1984, from 3- million to about 51- million units. Color TV sales in the same period jumped almost 15% to about 12 -3/4- million sets.

TELEPHONES FOR DEAF PEOPLE. A new portable, battery -powered device with an LCD screen attaches to a standard pushbutton phone and enables the caller to communicate with a deaf person. Called the Echo 2000, the varying tones generated by a caller's telephone pushbuttons causes letters to flow across the display in ticker -tape fashion. Measuring 7" x 4" x 1 ", and weighing only 10 ounces, Echo 2000 sells for $250. It's being made and marketed by Palmetto Technologies, P.O. Box 498, Duncan, SC 29334, under license from General Electric. ME

8 / MODERN ELECTRONICS / February 1985

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CIRCLE 87 ON FREE INFORMATION CARD February 1985 / MODERN ELECTRONICS / 9

www.americanradiohistory.com 11111111/NEW PRODUCTS/Ill/Il!-

For more information on products Pro -Lite's standard configuration described, please circle the appropri- includes: 256K of RAM, a single 3'h " ate number on the Free Information microfloppy disk drive, two expan- Card bound into this issue or write to sion slots, a Solid State Software the manufacturer. ROM drawer that holds up to eight 32K EPROM modules, a PC interface cable that allows the computer Full-Feature Portable to be connected with the TI Profes- Personal Computer sional and other MS -DOS com- Texas Instruments has put the power puters, and an external parallel of the traditional desktop computer printer port. into its 11.5'W x 10.5D "x 2.75 "H, Available options include: an ex- ous signals. Channel I /II sum /dif- 10.5 -lb. MS -DOS Pro -Lite lap por- pansion box that attaches to the rear ference can be obtained with channel table. Topping the new computer's of the computer for adding a second I inverted. The probe calibration list of features are a 12 " -wide flip -up microfloppy disk drive and battery signal is selectable between 1 kHz and LCD screen that can display up to 80 pack; an internal 300-baud auto -dial 1 MHz for hf probe compensation. A columns by 25 lines in the text mode, /auto -answer modem; an RS -232 component -test capability for check- a 78 -key full -travel keyboard, an on- synchronous /asynchronous inter- ing semiconductors or passive com- board 3'h " microfloppy disk drive face; an external color or mono- ponents externally or in- circuit is with 720K capacity, and 768 RAM chrome monitor interface; a portable built in. memory capacity. The battery -pow- thermal printer; an add -on 3'h " mi- Two x 1/ x 10 switchable probes ered portable computer is built crofloppy disk drive; expansion are included with the oscilloscope. around a low -power 80088 micro- RAM; an LCD graphics option; and $965. processor and can accommodate an a soft -sided carrying case. CIRCLE 91 ON FREE INFORMATION CARD optional 80087 numeric coproces- CIRCLE 90 ON FREE INFORMATION CARD sor. Its LCD screen supports both al- Wide -Bandwidth /Dual -Trace Advanced Radar Detector phanumerics and graphics (the latter Bench Oscilloscope optionally) and features adjustable Radio Shack's Micronta Road Patrol viewing angle and contrast control. Featuring a dc-to-60 MHz band- XK, a new generation, dual- conver- The keyboard has 12 user- program- width, dual traces displayed on an sion superhet radar detector that uses mable function keys, an imbedded 8 x 10 -cm internal -CRT graticle, and an advanced gallium -arsenide Schott- numeric keypad, and separate a post acceleration voltage boosted ky barrier diode detector, is said to cursor -control keys. to 14 kV, Hameg's new Model provide much greater range than HM -605 oscilloscope offers what ap- conventional systems. The GaAs de- pears to be an excellent package for tector is reported to be extremely sen- the busy service bench. The scope's sitive to both X- and K -band traffic technical specifications appear to be radar signals and much less noisy, good, too: 5.8 -ns risetime; 1 -mV /cm eliminating false alarms caused by in- with x 5 expander to 20 MHz and band nonradar signals. Sensitivity 5 -mV /cm to 60 MHz deflection coef- specifications for the X and K bands ficients; 1 -s /cm to 50 -ns /cm time- are - 110 and -102 dBm /cm2, re- base with 2.5:1 variable control and spectively. Bandwidth is rated at x 10 magnification to 5 ns /cm; ± 100 MHz, with center frequencies 100 -ns to 0.1 -s variable sweep delay of 10.525 and 24.150 GHz. in seven decade steps; and peak value Other key features of the system triggering beyond normal bandwidth are its multiple warning options, to 80 MHz at 5 -mm display height. which include a buzzer, a light, or a Standard scope features include combination of the two, and an LED ac, dc and line coupling, triggering signal- strength meter. Automatic po- on channel I /II and external, and al- larity switching and a detachable ternate triggering to view asynchron- power cord permit fast transfer of the

10 / MODERN ELECTRONICS / February 1985

www.americanradiohistory.com detector to any vehicle equipped with a cigarette lighter, regardless of ground polarity. Dimensions are

1 5/8"H x 5'/,2 "W x 57/32 "D. Hook - and -loop fasteners are provided for mounting. $199.95. CIRCLE 92 ON FREE INFORMATION CARD

gold -plated edge connectors and two prototyping areas. A large area, containing more than 2100 holes on 0.1 " centers, can accommodate 60 or more 16 -pin DIP devices, while the smaller area can handle I/O connec- Video Noise Filter tors and additional components. On If you video system is plagued by the board are fully socketed buffer electrical noise from the power line, ICs, a mounting bracket with hard- perhaps what you need is the Model ware for permanent installation in HB -1 Hum Block Humbucker from your computer, and power and VAMP, Inc. This new unit inserts in- ground buses on both sides and to any 75 -ohm coaxial video trans- around the edges. Also on the board mission line to remove or suppress is an 8- position DIP switch that per- power-line interference. It features mits user selection of up to eight uni- isolated BNC connectors, compact que addresses that cover the entire size (it measures only 2 " x 2 " x I/O address range. All address, data, computer. The Fast Load Cartridge 1 1/4 "), a color -coded metal enclo- and control bus lines are fully buf- is unlike other such products in that it sure, and convenient mounting tabs. fered. A cable connector provides works with even protected disks. Multiple HB -1s can be arranged to buffered I/O signals to the solderless Epyx says it works with about 95% of provide high packing densities in ap- eZ Board. $89.95 plus $5.00 P &H. the programs currently on the market plications such as inputs to video CIRCLE 94 ON FREE INFORMATION CARD for the C -64, including Flight switchers, routers, and VTR banks. Simulator, Load Runner and Sum- $89.95. Accessory Loads Disks mer Games. CIRCLE 93 ON FREE INFORMATION CARD Six Times Faster CIRCLE 95 ON FREE INFORMATION CARD If you own a Commodore 64 corn- IBM PC & XT puter, you can now load and power Outdoor Scanner Antenna Prototyping Board up disks up to six times faster and Until now, the scanner enthusiast has If you're a design engineer or the type copy disks up to 10 times faster with had to settle for either the built -in of owner who likes to build your own Epyx's new Fast Load Cartridge, ac- whip antenna on his receiver or a circuits for an IBM PC or XT com- cording to the manufacturer. The large outdoor antenna that required puter, Sabadia Export Corp. has a firmware cartridge plugs into the roof mounting with some sort of bus -pluggable prototyping board for C -64's cartridge port and operates mast arrangement. Hamtronics' new you. Called the eZ Card, it is a full - completely automatically. No extra length, double -sided board with instructions need to be typed into the (Continued on page 84)

February 1985 / MODERN ELECTRONICS / 11

www.americanradiohistory.com 111111111 PRODUCT EVALUATIONS 1111111111111111 Video Audio Plus Video Plus Much More: Sansui's A V-77 Processor - Controller

MI NANO VIM ROMP. M-77 ® a.. ,.. °" n , W. .... ,m °- , T . =- . .ON.. oo.,._., ,a. loom moo ,-,On rrb0 Prow

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As you get more and more involved as well as a socket for a 10 -pin camera ial cable for that purpose, and there's in audio and video, eventually you connector and a microphone jack. also a 3.3 -ft. remote control cable for reach the point where you would like As for video signal processing, the a video camera. to do more than just record TV pro- AV -77 offers SHARPNESS and DETAIL grams off the air and play them back controls to improve picture sharp- Control Layout on a high -quality video monitor ness and resolution. A selectable HUE The front panel of the AV -77 is basic- while listening to the sound tracks control allows you to exchange one ally divided into two sections: one through your audio component sys- primary color for another, or to handling audio signal processing, the tem. That's when many of us turn to "add" red, green or blue to the over- other taking care of video signal pro- home video movie making. With the all picture. Other special effects in- cessing. At the left, near the power purchase of a color video camera clude picture "solarization," in switch, is a TV /Video selector, which comes the desire to be able to do some which outlines of images are intensi- performs pretty much the same func- creative video taping. fied, while inner, solid -colored section it does on a VCR. In the TV set- Sansui's new AV -77 with a $350 tions of the picture are muted. An ting, input signals are fed right out suggested retail price, is designed to overall fader control allows you to again so that you can watch TV nor- satisfy such artistic cravings. At the fade in or fade out both picture and mally; in the VIDEO setting, video sig- same time, it provides some practical sound at the same time. Finally, there nals connected to the AV -77 are con- audio and video enhancement facili- is a vertical and horizontal "wipe" verted to an r -f signal and may be ties as well as a true control center feature with which one scene can be viewed on an unused channel (3 or 4). that can easily tie together all the gradually altered, vertically, hori- Six SELECTOR /DUBBING pushbutton audio and video components you zontally, or a combination of both. switches are used to select desired have now or are likely to have in the The AV -77 also allows you to do program source, to choose dubbing foreseeable future. For example, it signal processing of the audio por- sources and destinations, or to listen allows you to do tape duplicating be- tion of a signal. Included is a dbx to an audio tape recording. A ten -pin tween two VCRs or dubbing from a noise -reduction system and a special camera connector and video and au- videodisc player, component TV tun- circuit for synthesizing stereo from a dio input and output jacks, duplicat- er, video camera or audio component mono sound track. A microphone/ ing one of the sets of jacks on the rear to a VCR. source level control allows you to panel, are positioned beneath the se- RCA -type phono jack inputs for choose optimum levels when voice - lector pushbuttons. two VCRs, a video disc player or TV over narration is to be added to Audio -related switches and con- tuner and an audio tape deck are lo- previously recorded audio tracks. trols come next. These include a cated on its rear panel. For added The AV -77 has a built -in r -f con- mono /stereo mode switch, a micro- convenience in making temporary verter and can, therefore, be con- phone input jack, a microphone mix- connections to, say, a friend's VCR, nected to antenna terminals of a con- ing level control, a dbx selector there is a second set of inputs and out- ventional TV receiver. The unit is switch (with OFF, RECORD, PLAY, and puts for one VCR on the front panel, supplied with a 6'h -ft., 75 -ohm coax- DUB settings), a noise filter switch, a

12 / MODERN ELECTRONICS / February 1985

www.americanradiohistory.com switch labeled MULTIDIMENSION and back a VCR program, will cut out the introduced virtually no video fre- an AUDIO INSERTER switch. The dbx sound tracks currently on the tape quency attenuation, even at the top circuit, for those who are not familiar and allow you to play your own back- NTSC video frequency of 4.2 MHz. with it, is a two -way noise -reduction ground music or add "live" narra- However, if you have to connect the system that also improves the dy- tion (via a microphone). With this unit through its r -f modulator (in namic range (difference between switch activated, it is also possible to other words, hooking up the unit to softest and loudest sounds) of an add an audio source to the video the antenna terminals of your TV set audio program. For it to be effective, from a VCR and to dub the resulting and viewing pictures with unused an audio program must first be re- combination onto a second VCR. Channel 3 or 4), you will find that corded using the encoding side of the Video signal processing controls there is some slight loss of high video circuit. Then it must be played back are located on the right side of the frequencies. It's not enough to be no- using the decoding side. The dbx front panel. They include DETAIL, ticeable with ordinary TV sets or with noise -reduction system will only SHARPNESS and VIDEO ART selectors. VCR -taped programs (which lack work for newly made audio record- For the latter, there is PICTURE high picture resolution to begin with) ings; it won't reduce noise on older, (which controls the degree of "video but you might detect a slight loss of existing video tapes that have tape art applied), VERTICAL WIPE, HORI- detail when viewing live broadcasts hiss. For such tapes, the NOISE FIL- ZONTAL WIPE and FADER. As men- or Laservision discs on a high -quality TER switch would normally be used. tioned earlier, the FADER control is video monitor. The MULTIDIMENSION switch, used to fade in or fade out video and Sharpness and detail controls not when pressed, introduces a phase - audio signals simultaneously. The only compensate for this slight atten- shifting circuit between left and right other three VIDEO ART settings relate uation, but act to "boost" high video channels, increasing apparent stereo to the primary color that is added to frequencies which, in turn, improves effects of a stereo signal source and the existing picture. picture detail. The trick here is to use creating a synthesized pseudo- stereo these controls judiciously, balancing effect when mono audio signals are Lab Performance the slight increase in "snow" or fed to the unit. The AUDIO INSERTER With the AV -77 connected via its video noise against an improvement switch, if depressed while playing video "in" and "out" jacks, the unit in picture detail.

Fig. 1. Amplitude-vs-frequency response plots from left Fig. 2. Multiple exposure shows phase relationship of left (upper) and right (lower) outputs ofA V-77 with stereo syn- and right audio outputs at three different frequencies with thesizer circuit activated. stereo synthesizer on.

FR dB

+10 -_ . __--- - + 0_ _

10 - .- _ , + 10 = ------= r 0 , I *' -10 Ï

20 50 100 200 500 1K 2K 5K 10K 20K Frequency-Hz 10dB/D L+ 0.0dB R+ 0.0dB 940Hz

February 1985 / MODERN ELECTRONICS / 13

www.americanradiohistory.com PRODUCT EVALUATIONS Sansui'c A V-77 Processor continued

fade -out to "black." As for the FR VIDEO ART 1, 2, and 3 switch positions dB and controls, it's difficult to describe visual effects that they produce, E the beyond what I've already said earlier. The controls provide interesting and colorful "wipes" of parts of a ! scene, both vertically and horizontal- +10 ly, but don't get the mistaken notion

o that these controls are going to allow 0 you to do a real "transitional "fade" from one scene to another. i 10 Audio Signal Processing - 20 Audio frequency response, signal -to- noise ratios and harmonic distortion 20 50 100 200 500 1K 2K 5K 10K 20K readings were all excellent compared with what you can expect from most 10dB/D L- B. OdB B.10kHz VCRs or even from the audio circuits of most TV monitors and receivers. Fig. 3. Sharp cut -off filter reduces audible effects of noisy audio sound tracks The AV -77 is not likely to degrade from VCR tapes. Dotted-line cursor is set at -3 -dB point. audio fidelity of any of your audio or video program sources if you intro- duce it into the audio signal path of your component audio system. The SHARPNESS control picks up However, I found that if I hooked up The stereo synthesizing circuitry the amplitude of frequencies around the AV -77 via the TV output (and the works very much like other such cir- 1.25 MHz to 2.0 MHz, while turning antenna input on my TV set), signal - cuits found increasingly in audio sec- the DETAIL control fully clockwise to -noise ratios deteriorated until they tions of audio /video devices. Essen- boosts higher frequencies from were only marginally better than tially, it alters the phase and the re- around 2.0 MHz to 3.58 MHz. The what we normally expect from taped sponse of one channel relative to the effect upon the picture is precisely programs played back on a good other. The graphic plot of Fig. 1 illus- what the two terms imply. The VCR. This was especially true of trates this effect. The plot is from 20 SHARPNESS control seems to improve noise referenced to luminance or Hz to 20 kHz; vertical calibration is the overall crispness and clarity of a brightness video signal, less so for 10 dB per division. As for phase dis- scene viewed on my monitor screen, chroma noise. Therefore, if you ex- placement between the two channels, while turning the DETAIL control to pect to use the DETAIL and SHARP- this is best illustrated by the `scope maximum rendered tiny details of the NESS controls near their maximum photo of Fig. 2, in which I applied the picture more discernible. Using both settings, it is especially important output of the left channel to the ver- controls maximally, of course, re- that the hookup be made using the di- tical input terminals of the oscillo- sulted in both types of improvement, rect video output jacks of the AV -77. scope, and the right channel output but as is true of all enhancement con- These settings yielded the poorest sig- was connected to the horizontal in- trols of this type, background noise nal -to -noise (highest levels of back- put. Input to the AV -77 was, of increased visibly. ground noise and snow in the picture) course, a single test frequency. If the Video signal -to -noise was far bet- when I hooked up the system via the two outputs were in phase, we would ter than what you can expect from r -f or TV output. have seen a straight line sloping diag- any VCR tape, so long as connection The fader control was effective, al- onally to the right, from bottom to was made via the VIDEO OUT jacks. though it does not provide a complete top. Evidence of phase displacement

14 / MODERN ELECTRONICS / February 1985

www.americanradiohistory.com is apparent, as you look at the three Beta III in the case of Beta - format worthwhile audio /video accessory. different ellipses that were produced machines). As for the "art" special effects, with three different test frequencies they're for the more creative video re- (1 kHz, 5 kHz and 10 kHz) in this cordist. Unless you've in this cate- Conclusions multiple- exposure photograph. gory, you probably won't be using Frequency response using the I found the AV -77 easy to install and, them all that much, though they are noise -filter switch is shown in Fig. 3. after a bit of experimentation and certainly an interesting feature. The cutoff point ( 3 dB) occurs at use, easy to work with. You will find As far as I am concerned, the San - just above 3.0 kHz when the filter is that the Sansui AV -77 gives you a sui AV -77 would be worth its afford- turned on, so you would use this fea- measure of switching flexibility that able price even if those particular spe- ture only to decrease extreme tape would be difficult to obtain with sim- cial effects were omitted from the hiss such as you might have with a ple video switchers. Add to that the product, though it would be less com- VCR tape recorded at the slowest enhancement capabilities of the San - petitive in the marketplace should tape speed (EP in the case of VHS; sui processor and you have a very they not be used at all. -Len Feldman

CIRCLE 98 ON FREE INFORMATION CARD

Video Meeting The 8 -min Threat: Zenith's New VHS Camcorder

coming on strong, too, with camcorders designed to use traditional % " video tape. One of the first VHS offerings in this arena, and the subject of this review, is the JVC -made Zenith Model VM6000 camcorder. Using existing VHS technology, the Zenith camcorder works with standard 'h " -wide tape, though in a compact 20- minute videocassette that requires use of a special adapter to permit playback in a standard VHS deck. Since tape width and track recording format are the same for both standard and compact (the latter called VHS -C by originator JVC) cassettes, a tape recorded in a VideoMovie camcorder (like the Ze- nith Model VM6000) can be played back in a standard VHS deck. Combination video camera /record- Polaroid. (See the review of Kodak's Like its competition, the Model ers- so- called "camcorders" -are 8 -mm camcorder, January 1985, and VM6000 is light in weight, compact, becoming a hot item for home movie "Camcorders -A Revolution In and designed to be battery powered. making. Interest in them is being pro- Home Movie Making," November It offers the most -wanted home moted and fanned by both video and 1984.) Not to be outdone in their own movie making features and func- photographic -film manufacturers, area of expertise, JVC and Sony and tions, including an electronic view- including such giants as Kodak and their VHS and Beta supporters are finder with multi- function on- screen

February 1985 / MODERN ELECTRONICS / 15

www.americanradiohistory.com PRODUCT EVALUATIONS Zenith's New VHS Camcorder continued

Top trace views large resolution Tektronix chrominance channel REC horizontal -resolution chart chart with extended grey scale, shows evaluation chart reveals blues and shows usual 3 -MHz extended fre- good reproduction with no outstand- magenta a little light (top). Relatively quency for consumer cameras (top). ing problems. Bottom trace shows good reflectance chart (bottom) re- Bottom trace shows obvious color full EIA linearity chart with only veals surprising linearity and exact distortion when pictures are recorded slight rolloff on left. center crossover. from the screen of a CRT.

displays and a 6:1 Zoom lens with the rechargeable nickel -cadium bat- manual /automatic zoom selector; macro setting and manual focus cap- tery pack are equal. automatic /variable iris control; a UP ability. Suggested retail price of the The camcorder isn't equipped, as sensitivity switch for low -level light- Model VM6000 is $1495. is, to process broadcast programs off ing conditions; a standard /adjust- the air. However, the sync chain is able white -balance control; daylight/ General Comments good enough to record pictures, indoors filter switch; memory tape The camcorder weighs just 4.3 lbs., through the camera, from the screen marks; and a counter RESET button. less its lightweight battery pack, and of any TV receiver and produce pass- The final second of any scene is vis- measures a compact 12% "L x 5% "H able results on playback. ible through the viewfinder whenever x 4%6 "W. Adding its electronic view- Optional extra -cost items for the recording ceases. During pauses of finder and battery pack and add both camcorder include: a cassette adapt- longer than 6 minutes, Zenith advises weight and size, but not to the point er ($39.95) for playing back VHS -C that power be turned off, since where the camcorder is unwieldy. compact cassettes in a standard VHS there's not low -power standby ar- The business end of the camera deck; 20- minute VHS -C videocas- rangement for continuously keeping contains a '/ " static- magnetic high - settes ($7.99 each); 30- ($29.95) and the CRT filament alive. band Saticon pickup tube. In front of 45- minute ($39.95) rechargeagle bat- In setting up this camcorder, the the tube is an f/1.2, 8- to -49 -mm tery packs; an ac power supply /bat- appropriate filter position (daylight zoom lens. Camera sensitivity with tery charger ($129.95); a shoulder or indoors) and standard or auto- this arrangement is 15 lux, or 1.4 foot mount and strap ($39.95); and a rigid matic white balance are selected first. candles (fc). carrying case ($109.95). Then standard or increased CRT sen- Recording and playback are han- sitivity, the latter used under low - & dled by a four -head helical -scan sys- Controls Functions light conditions when a white line in- tem. With its 270 ° tape -wrap around The camcorder has all the usual dicator appears in the lower portion its miniature head drum and parallel transport controls, including REC (re- of the viewfinder, is selected. Next, loading system, the camcorder's cord), PLAY, PAUSE, STOP, EJECT, the iris switch is placed in the BLC transport permits rapid stop, play TRACKING, F -F (fast- forward), and (backlit), standard, or close position. and pause functions. REWIND. Supplementing there are a This setting depends on whether you Power consumption from the cam- power zoom control, with T and w need special illumination, regular corder's 9.6 -volt battery pack is 8.9 positions for telephoto and wide - pictures, or closeups. Finally, the watts. Charge and discharge times of angle adjustments; a focusing ring; a camera is turned on, the lens is fo-

16 / MODERN ELECTRONICS / February 1985

www.americanradiohistory.com Camcorder's good S/N measure- Video (left) and audio (right) carriers Response of 10 dB down at 10 kHz is ment of 43 dB is better than average. separated by 3.58 MHz exhibit excel- not too bad, especially with a micro- lent C /N, fairly good vestigial side- phone input and an "anyspeak "tone band suppression (left). Subtract 2.5 signal source. dB for the analyzer.

cused throughout its 6:1 range, the halogen or tungsten lights. If manual lens while you monitor the viewfind- earpiece is plugged into its jack (if adjustment of the white balance con- er's white balance indicator to ob- sound monitoring is desired), a cas- trol is required, the camera is simply serve when flickering ceases as you sette is inserted, and the camcorder is aimed at a white or monochrome area adjust the control. ready to be set up for recording. and you zoom in with the telephoto There are eight possible indica- If you wish to preview or rehearse a scene before actually recording it, Zenith Model VM6000 Laboratory Analysis you press the REC button to view it in the viewfinder. Pressing just the REC Dc power drain (at 9.6 volts) 8.9 watts button won't start the tape rolling. Tape speeds (with TC -20 tape) Record /play " per second To actually record on you must tape, Shuttle search 3 x normal press the REC and PLAY buttons si- Fast forward 2 minutes multaneously to first put the system Rewind 1 minute into the record /pause mode. At this Record /play time (TC -20 tape) 20 minutes point, getting the scene on tape simp- Play start time '/, second Record time (from pause) 'A second ly requires the recording trigger Low light level (maximum) 15 lux (1.4 fc) switch to be pressed. Luminance S/N 43 dB As the camera "rolls," the iris can Vertical resolution (at baseband) 300+ lines be adjusted for various exposures, Horizontal resolution (at baseband) 3 MHz and fade -ins and -outs can be tried. A Grey -scale linearity good Color reproduction fair fixed iris is suggested when expe- Maximum record /play/rewind time with riencing backlighting and for bright VAC -402 battery 40 minutes sky under maximum zoom, dark -to- Audio response (with microphone and available light scene panning, and when there's speaker l0 kHz at -10 dB passage of a white body across the Wow /flutter (NAB at 3 KHz) 0.1301o/0.2707o Battery charge time 40 minutes scene being recorded. Test equipment: Tektronix Models 7L5 and 7L12 spectrum analyzers; Hameg Model HM 605 Normally, the white balance con- oscilloscope; B&K- Precision Models 1250 NTSC and 3020 function generators and 1035 wow trol doesn't have to be used when re- and flutter meter; Data Precision Models 945 multimeter and 585 8 -digit frequency counter; cording outdoors under daylight Tele- Measurements, Inc., precision registration charts; RCA Model VGM2023S TV re- conditions and indoors when using ceiver /monitor.

February 1985 / MODERN ELECTRONICS / 17

www.americanradiohistory.com PRODUCT EVALUATIONS Zenith's New VHS Camcorder continued

tions that can appear in the viewing effects. This improves resolution MHz chroma becomes downcon- finder: in the frequency special range between verted to a more convenient 629 kHz. A long white line in the pause 400 and 700 nanometers. Outstanding These two signals are processed mode signifies that the REC and PLAY features of this tube are low dark cur- separately, delayed, filtered, modu- functions are engaged; rent, small (capacitive) image lag, and lated, demodulated, and mixed be- This line diminishes in length and stable black signal level. fore finally reaching the recording blinks to indicate an approved oper- Images from the Saticon pass to a mechanism. ating condition during recording; preamplifier as horizontal and verti- In ordinary VHS equipment, tape Dropping of the line to the lower - cal sync, and high voltages drive the from the videocassette is wrapped left corner indicates that the scene is tube's deflection circuits and accel- around the 62 -mm head drum for underexposed; erate cathode electrons. At the same 180 ° and drum rotation is at 30 revo- Whitening and flickering of the time, iris, zoom action, shading, etc., lutions per second (rps). In this cam- upper -left quarter of the viewfinder regulate image pickup quality. corder, which uses a compact VHS -C screen indicates insufficient battery Luminance (Y) information is fre- tape cassette, tape wrap is 270 ° power; quency restricted by a 3.9 -MHz trap, around a 41 -mm drum and rotational *An increase in white -line blink while chroma (color) must navigate a speed is 45 rps. This assures equiva- rate indicates that remaining record- 3 -to -4 -MHz bandpass filter and de- lent recordings and continuity being time is one minute or less; lay line prior to red and blue separa- tween standard VHS and compact * Lighting of the lower -left corner tion. R/B tracking and shading cir- VHS (VHS -C) formats. indicates low picture sensitivity; cuits then channel their respective The head drum is driven by a three - A flickering white square in the colors to red and blue demodulators, phase direct -drive motor. The cap- upper -left corner indicates the need which convert them into red- minus- stan motor is another direct -drive for white balance adjustment; luminance (R - Y) and blue-minus- type, regulated by the mechanism Red and green lamps indicate se- luminance (B - Y) signals, where control circuit (meachacon) and the lection of the indoors and outdoors they are subjected to white balance servo circuits. Meachacon controls filters, respectively. adjustement before mixing. forward and reverse rotation, brak- You'll want to catalog or commit In the modulator /mixer, color is ing and speed, while the servo circuit to memory the above before operat- modulated onto a standard 3.58 - regulates speed and phase during re- ing this camcorder, since they're not MHz subcarrier originated in the cord and playback and counters any identified internally. If you also want sync generator (SSG), bandpass fil- load changes. to use the memory locator mark and tered, and delivered to the recorder. Along with a 4 -bit microprocessor electronic tape counter, just push the Meanwhile, luminance passes and copious logic, there are three ser- appropriate buttons under the STOP through its gamma correction circuit vo systems for drum video head, cap- and EJECT buttons. (the logarithmic reciprocal of picture stan tape transport phase and speed, During playback, operating the tube nonlinearity), is aperture (open- and tape back -tension. Unfortunate- PLAY, PAUSE, REWIND, F -F (fast -for- ing) corrected in the contour circuit, ly, dc motors are subject to both load ward), and STOP buttons causes a timing equalized (with delay), SSG and voltage variations and must, small LED to light whenever each mixed with the vertical edge- compen- therefore, be rigidly controlled in function is engaged. For playback, it sating signal, white and black level critical applications. will be necessary to also select audio clipped, and clamped at pedestal The 4 -head system (each head is and video outputs for feeding a TV level, with blanking added during re- separated around the drum's circum- monitor or channel 3 or 4 for feeding trace. Thereafter, luminance mixed ference by 90°) writes four slanted in- a standard TV receiver. with vertical and horizontal sync dividual video tape channels during passes to both the recorder and view- recording and reads four in play- Theory Of Operation finder as composite video in what is back. Each field and set of heads re- The '/z " single -color pickup tube used identified as E -E and explained as cords at 75 ° rotation of the head on this camcorder is a high -band Sati- electric -to- electric output. drum, while electronic head switch- con with built -in cross -stripe filter. Its Standard amplitude -modulated ing permits the two sets to complete a very thin photosensitive layer reduces luminance (Y) information becomes full frame. flare and other incident light -scatter- frequency modulation and 3 -to -4- Audio, of course, is recorded and (Continued on page 85)

18 / MODERN ELECTRONICS / February 1985

www.americanradiohistory.com Professional Books That Help You Get Ahead -And Stay Ahead!

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www.americanradiohistory.com Electronic Automotive Anti -Theft Alarms A look at the newest offerings, step -by -step installation procedure, and a rundown on some of the best electronic systems to protect your automotive investment

By Ron Cogan "chop- shop" artist to the joyrider What you really need is a reliable who simply wants your wheels to go electronic auto -theft alarm. for a spin without your permission. Installing an electronic theft alarm And the easier you make it for a thief in your vehicle adds to your peace of your car, van, camper or RV to take off with it, the more attractive mind. It also has the benefit of prob- can be a target for thieves any a target your vehicle becomes. ably saving you money on insurance. time and any place. It doesn't With auto -theft incidents increas- is rate with each matter is your vehicle brand spank- ing at an alarming Early Theft Alarms ing new or five or more years old, passing year, it pays in more ways either. It's an attractive target for than one to take direct measures to Before the age of solid -state electron- every thief, from the professional ensure the safety of your vehicle. ics, if you owned a vehicle, your best

22 / MODERN ELECTRONICS / February 1985

www.americanradiohistory.com February 1985 EVICS

tion. But even if you always remem- micro -circuit technology, they were bered to arm the alarm, an aspiring and still are designed to address all thief might notice the key switch and the shortcomings of the first- genera- simply deactivate the system before tion designs. breaking into your vehicle. Virtually all of the new vehicle Other problems also existed. For theft alarms sold today can be suc- example, if the alarm was triggered cessfully installed by do-it- yourself- and you weren't in hearing range for ers, even those with no technical hours on end, the system's siren or knowledge of electronics or automo- horn would continuously sound until tive mechanics. Only simple tools are the battery ran down or you returned needed to perform the installation. to turn if off. Often as not, you came And the instructions provided with back to a dead battery and irate each model are generally well illus- neighbors or store owners who want- trated to guide you, step -by -step, ed to lynch you for disturbing their through installation. peace. The noise problem became so An example of these new genera- acute that many municipalities have tion security systems is the CAT ordinances on the books requiring ( "Catch A Thief ") alarm from Cali- the towing away of offending vehi- fornia Electronics Industries. Like cles and disarming of the alarm if the many of the top -notch alarm systems owner couldn't be found -at the now available, the CAT alarm offers owner's expense. passive arming. That is, it arms and Another irritating problem with disarms itself automatically. You early electronic theft alarms was false don't ever have to even think about triggering. This was an aggravatingly the system except when entering or common occurrence. Though the pin leaving your vehicle. switches used to guard against unau- Arming and disarming of the CAT thorized door entry worked well, the system is accomplished from the same couldn't be said for the first - vehicle's ignition switch. When you generation motion detectors that turn off the ignition and are pre- some alarm systems used. The idea of paring to leave your vehicle, the sys- using motion sensors was to detect a tem initiates a one-minute exit delay thief in the process of breaking in, before arming itself. If you wish to bet was to keep a watchful eye on it. rather than after he gained entry. Ad- remain in your car with the ignition With the advent of electronics came a ditionally, the sensor would also trig- off for longer than the one -minute new option -the electronic alarm ger the alarm if a thief attempted to grace period, all you have to do is system. Although early alarms were tow the vehicle away or jack it up to leave the key in the ignition switch very basic in design, they did at least steal the tires and wheels. and turned to the "accessory" posi- afford some degree of protection Unfortunately, early motion de- tion. Upon returning to your vehicle, against theft of a vehicle and /or its tectors were prone to false triggering you have up to one full minute (the contents. It was an important step in at the slightest movement caused by time is adjustable to suit your person- the right direction, but it didn't go wind or even simply by someone al preference) to unlock and open the quite far enough. brushing against the vehicle. An- door, slip into the driver's seat, and There were a number of drawbacks other disappointing limitation of the switch on the ignition to deactivate with the simple designs of the early motion detector was its requirement the alarm. electronic theft alarms. To begin that the vehicle in which it was in- Monitoring with the CAT system with, you had to manually arm these stalled had to be parked on level is accomplished in several ways. The systems with a key- operated switch ground. Parking on an incline im- alarm is connected to your vehicle's mounted in an inconspicuous loca- mediately triggered the alarm. existing dome -light switches located the vehicle. Since the in the car's door jambs. (If no such tion outside A New Day Dawns system was manual, its success in switch is present, pin switches sup- protecting the vehicle depended al- Beginning about 10 years ago, a plied with the alarm kit must be in- most entirely on the imperfect mem- whole new generation of vehicular stalled in the jambs to do the job.) ory of the user. If you didn't remem- theft alarms began to come on the The system also has a sophisticated ber to arm your theft alarm, your market. Using much more refined dynamic motion detector, with ad- vehicle was left without its protec- electronics built around the latest in justable sensitivity, that senses har-

February 1985 / MODERN ELECTRONICS / 23

www.americanradiohistory.com monic disturbances, such as a sharp When an intrusion is detected, the tery in the event a break -in occurs rap on the window or a jolt to the system's 110 -dB (decibel) siren when you're away from your vehicle body. Additionally, a closed loop sounds for a full minute after the dis- for an extended period of time. can be used to protect individual ac- turbance ceases. After this, the alarm The CAT alarm is simple to install cessories, and a circuit is provided resets itself to continue surveillance. by the average do- it- yourselfer in that can be tied to an optional trans- This feature eliminates the possibility about an hour. Installation tasks in- mitter /pocket -pager system. of running down your vehicle's bat- clude finding an out -of- the -way loca-

Do- It- Yourself Installation The following series of photographs demonstrate the steps taken to retrofit the California Electronics Industries CAT anti -theft vehicle alarm. The installation procedure described here is generally typical of that for most of the other such security systems on the market. Only very basic tools are required to retrofit the alarm system in a vehicle.

1. Installation of the CAT security system begins with 3. Route the appropriate conductor from the glove box un- finding an out -of-the way, hidden location in which to der the carpeting or behind the kick panels to the door pin mount the alarm module. A good place is the glove box. switch. Use the brown conductor for a ground- activated Drill a hole through one corner of the glove box to provide door switch or the yellow conductor if the pin switch is pos- a means for routing the wiring to the alarm module. itive activated. (See the wiring diagram in step 14.)

2. Dismount the existing door jamb pin switch to deter- 4. Feed the conductor through the doorswitch hole and mine if it positive- or ground-activated. Use the appropri- connect it to the switch with an insulated Scotch -Lok con- ate conductor in the wiring harness -yellow or brown. If nector. Remount the switch in its hole. Most cars require your vehicle doesn't have door pin switches, you must in- connection to only the front door. In the case of Mercedes a stall the grounding ones supplied with the CAT kit. wire must also be connected to a rear-door switch.

24 / MODERN ELECTRONICS / February 1985

www.americanradiohistory.com tion for the central alarm module, separate power leads, one that's The steps detailed in this photo se- tapping leads to the vehicle's dome - "hot" all the time and the other quence are typical of those for instal- light switches, and routing wiring that's "hot" only when the ignition lation of all such alarm systems. through the firewall and into the en- key switch is turned on. In conclusion, it goes without say- gine compartment. Inside the engine The entire installation procedure ing that a good hoodlock to prevent a compartment is where you mount the for the CAT system is illustrated in thief from disconnecting the alarm siren and make connections to two the photographs below this article. should supplement any alarm.

5. The power, ground, and trumpet conductors must be 7. Route the gray conductors comingfrom the wiring har- routed through the vehicle's firewall and into the engine ness and attach them to the terminals on the trumpet speak- compartment. Be sure to route through a rubber grommet er with insulated connectors. This done, dress the wires to prevent the metal edge of the hole from cutting through away from other wiring and hoses in the engine compart- the insulation and shorting out the system. ment and secure them in place with plastic cable ties.

6. Drill holes for and mount the trumpet speaker in a loca- 8. Use a multimeter, set to dc volts, to locate appropriate tion inside the engine compartment where it won't be ac- sources ofpower for the alarm system. One source must be cessible from outside the vehicle. Secure it in place with "hot" at all times, while the other must be "hot" only three screws or rivets. Use one of the mounting screws or when the ignition is turned on. Find the first with the igni- rivets to make the system's ground connection. tion off, the second with it first turned on and then off.

February 1985 / MODERN ELECTRONICS / 25

www.americanradiohistory.com 11. To test the operation of the alarm system, turn on and then off your vehicle's ignition system. Shut all doors and wait a bit more than 60 seconds to allow the system's exit delay to expire. Then open a door. When the preset entry delay time runs out, the alarm sound.

9. In this installation, the power conductors are being soldered to the terminals of the fuse block. However, ifyou wish, you can use clip -on fuse taps or insulated tap connectors to tap into the two power sources. You may have to do the latter is there's only limited access to the fuse block. 12. Time the entry delay from when the door isfirst opened until the alarm sounds. If you find this to be a comfortable amount of time for you to get into your vehicle and turn on the ignition, do nothing. If not, however, adjust the thumb - wheel control at the side of the module as needed.

10. All wiring completed, the alarm module is ready to be 13. The sensitivity of the motion -detection system is also set into the glove box (or wherever you've decided to put adjustable to suit individual requirements. You'll have to it). Connection to the newly installed wiring is via a conve- make this adjustment by trial and error, delivering sharp nient quick- disconnect fitting. Don't anchor the module in blows to a window or tire while adjusting the screw in the place until adjustments are made to make it operational. alarm module until sensitivity is set as you want it to be.

26 / MODERN ELECTRONICS / February 1985

www.americanradiohistory.com The Best Of The Rest

Here's a look at 10 other sophisticated vehicle alarm systems. The models detailed below and shown in the photos are only representative of the marketplace. There are many more makes and models available; in fact, most of the manufacturers mentioned here offer more than the one or two models described. The bold numerals are keyed to the same numerals below each photo in this section.

1. The Model AP -4200 alarm system ($189.95) from Auto page boasts a radio paging system that personally notifies you in the event of a break -in. This system automatically arms itself whenever the vehicle's engine is turned off, and it monitors for high- frequency metallic sounds, such as those typically v made by a "slim jim" or pry bar, with a pair of resonance sensors. The trans- 12 Volt O mitter also houses a plus /minus trigger When Alarm On output for other sensing devices, such as pin switches and motion detectors. Metal Frame Once the system is triggered, the hid- Chassis den 4-watt transmitter sends out an in- dividually tone -coded signal (up to Pin Switch 30,000 combinations are possible) to Hood or Trunk 2 I O I the beep tone and flashing O u activate 'E 1f1ßJl. light in your pocket pager. L Toggle Switch Or 2. Cal Custom's Model 981 "Smart Chassis Alarm" ($69.95) is extremely simple to Ground i install, since one enclosure houses all Dome Light 1_ the electronics, a 115 -dB (decibel) electronic horn, and a shock sensor. This

1 Io alarm is unique in that it has its own Metal Frame Iw built -in battery backup in the form of Door or Pin Switch two 9 -volt alkaline batteries. Hence, Switch or or Switch Metal Frame Pin Switch +12V the alarm is powered even if your vehi- Chassis (Grounded) cle's battery cables are cut. The alarm Ground offers passive operation via the igni- Clockwise tion key, an adjustable exit delay, and a More sensitive valet override switch. The deluxe Counter-clockwise Model ($99.95) adds a three -LED Less sensitive 982 status monitor and a tone that alerts you to the fact that the entry delay More Time Counter timer is running. It has a logic-con- Clockwise Less Time trolled exit delay that doesn't arm the Clockwise system until you actually leave your vehicle, and it flashes the headlights 14. Wiring diagram of California Electronics CAT auto -theft alarm. when the alarm is tripped.

February 1985 / MODERN ELECTRONICS / 27

www.americanradiohistory.com (1) (2)

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3. California Electronics Industries' 4. Chapman's "Generation III" Sys- imum security and reliability. Dual - Model 4400 standard "CAT" alarm tem 400 boasts a high- security key channel remote control features a ($189.95) is a totally integrated, lock and hood deadbolt as well as an remote panic button for emergen- passive security system that is oper- ignition suppressor that prevents cies, or protection for two vehicles ated by your vehicle's ignition key. your vehicle from being driven away with only one transmitter. The sys- Utilizing microcircuit technology, the until the system is disarmed. A detect tem can be armed either actively with CAT packs a lot of features into a module and motion detector protect the transmitter or passively with the small central alarm module, including against unauthorized entry, jacking, vehicle's ignition. An indicator a built -in dynamic motion detector, and towing. When the alarm is trig- "chirp" signals whether the system is entry and exit delay, automatic shut- gered, a 110 -dB motor -driven siren armed or disarmed and when intru- off and rearming, and current sensing sounds for three minutes and then sion has been attempted. Other fea- to protect against door entry. A shuts off to allow the system to rearm tures include ignition kill, backup 110-dB high /low siren is activated to guard against further intrusions. battery system, and closed -loop cir- when the system is triggered to attract cuit to protect accessories. immediate attention. Also available 5. Featuring very low -power CMOS 6. The "Vandal Alert" Generation II from CEI is the Model 2000 4 -watt circuit design, the Crimestopper anti -theft system ($129.95) from pager ($199.95) that alerts you by Model HP -7507 "Remote Guard" Criterion Associates incorporates a radio from as far away as four miles if alarm system ($399.95 to $429.95) solid -state electronic design that per - someone tampers with your vehicle. offers a host of features for max- (Continued on page 86)

28 / MODERN ELECTRONICS / February 1985

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www.americanradiohistory.com .S. installations will soon top on, `" ton, as receiver /antenna systems get better and become less costi

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www.americanradiohistory.com Video

By Stan Prentiss

By March or April of this year there will be one -million television receive -only (TVRO) home earth stations operating in these United States, according to Dr. Taylor Howard of Chaparral Com- munications and other knowledge- able industry sources. With the TVRO industry now pulling in $9- billion in revenues, projected figures Fig. 1. Birdview Model 20/20M stereo satellite receiver comes with aluminum suggest that 60,000 per month will be dish, antenna drive controller, remote satscan. a reasonable output, with 3.7 -to- 4.2 -GHz downlink C -band equipment predominating for now and in With hundreds of transponders on vised to try first and buy later when forseeable future. the the C and K bands raining signals attempting to shortcut the process. Although several programmers, earthward from geostationary orbit Transponder signals at -100 dB such as HBO (Home Box Office), 22,300 miles up in space, the evident aren't exactly boomers, especially at continue to suggest imminent cod- need for dual -polarity (orthogonal) K -band frequencies when it rains or ing /decoding (scrambling) schemes, receptors, multiple TV drivers, and C -band frequencies in northern New as Dr. Howard confirms, adequate higher i -f receiver inputs was appar- England. And mismatched or "alien" and reliable technology "isn't quite ent. Rapid introduction of both mesh LNA, LNC, or LNB dish /receiver there." (HBO predicts scrambling on (wire) and perforated (sheet alumi- component systems can only aggra- Galaxy 1 and Satcom in 1985.) Even num or steel with holes) dishes for vate the problem. if live up to its an- HBO should see -through cosmetics, easier ship- nouncement, there are other satel- ping, and less wind resistance de- lites and transponders from which to manded considerable attention. And Specific Developments Besides, HBO choose. the Linkabit to reduce prices still further, as low - Birdview's 20/20M stereo satellite re- price tag descramblers have a dealer noise amplifiers (LNAs) plummet, b- ceiver (Fig. 1), with 8'h -ft. spun -alu- of some $300 each. and 8 -ft. receptors were much in evi- minum dish, antenna drive control- dence, along with the traditional 10- ler, and 140 ° remote (sat)scan is a General Developments and 11 -ft. models for tougher recep- ready -to -go system. Its LNB and It's best to concentrate on trends and tion areas. dual amplifiers require no polariza- new developments among TVRO Apparently, some of the manufac- tion and synthesized quartz- accurate manufacturers as 1985 gets under turers have the word that TVROs channel selection needs no fine tun- way. The huge Space /STTI satellite "with thermally noise limited sys- ing. A new 4 -way line splitter divides earth station show at Nashville's tems will not be affected at 32 to 25 signals into four sets, allowing multi- Opryland hotel this past fall set the log O within a 6- to -7 -dB C/N (carrier - ple receiver connections and inde- stage for advanced electronics and to -noise ratio) limit, since the aver- pendent tuning of any and all receiv- dish design for the future. Occupying age person won't usually see interfer- ers, regardless of signal polarity. The 531 booths and trailing 330 antennas ence upon institution of 2 ° satellite one -piece spun -aluminum antenna of all descriptions, the Society for spacing." If there's a 13- or 15 -dB handles winds of more than 100 mph Private and Commercial Earth Sta- C/N and a 6- to -7 -dB threshold, sig- without cracking, corrosion, or heat tions and Satellite Television Tech- nal loss will amount to between only buildup, due to the metal and white, nology, Inc., had a sell -out crowd of 0.1 to 0.2 dB. Furthermore, small an- oven -cured polyurethane base paint. more than 10,000 visitors. Technical tennas requiring noise relief can be Antenna gain amounts to 38 dB, and training certification, dozens of served by 15 -MHz (instead of 28- efficiency is 63 %. Feed to the anten- seminars, banquets, and Congress- MHz) receivers and pick up an extra 3 na is prime focus. men W.J. Tauzin (D -LA) and Albert dB. So there are apparently lots of The dual low -noise block convert- Gore, Jr. (D-TN) were among the ways to beat high costs and backyard er has an LNA noise temperature of show attractions. monstrosities. However, you're ad- 90 ° and an i -f of 500 to 1000 MHz.

February 1985 / MODERN ELECTRONICS / 33

www.americanradiohistory.com programmable infrared remote -control system with automatic satellite positioning, polarity and skew; a nonvolatile memory; a SAW resona- tor modulator; a two -digit LED channel display; a signal- strength meter; baseband video and audio outputs; a loop for connection of an outboard descrambler; a composite output for stereo processing; and a 430 -to- 930 -MHz i -f. Receiver bandwidth is some 24 MHz wide, and receiver threshold is approximately 9 dB C /N. Best of all, to avoid blooming reds and agc prob- 1111111111111. lems, this receiver has an extended 40 -dB agc range, and the converter oscillator tracks within ± 2 ppm over Fig. 2. Regency SR5000 comes with block down converter, LNA. a - 30° to + 60 ° temperature range. You get a choice of antennas to go with the receiver. The audio section includes subcarrier $3195, depending on extras chosen. The infrared remote controller 1 and 2 tuning, switch selection of Regency's Model SR5000 satellite features up /down channel scanning, audio stereo format, and L, R, video receiver (Fig. 2) also has outstanding volume and video tuning, muting, and 5 -Hz to 8 -MHz unclamped base - qualities and, like Birciview, is 10007o power on /off switching, run, and di- band output. American made. Supplied with a rect address. An infrared remote controller ad- block down converter mated to a 950 Radio Semiconductor of State justs transponder and local /satellite LNA, the receiver sells for $939.95. College, PA markets the LOCOM selection. It also permits selection of Among the receiver's many fea- LNB 950, Model BR101 receiver, one of two transmit data rates. Price tures you'll find: handling of multi- and Model LA10 line amplifier, all for the package ranges from $2995 to ple, multi -tuned receivers; a fully with enviable specifications and

Fig. 3. Radio Semiconductor LOCOM LNB 950, BR101 Fig. 4. Tracker Mounts has programmable and hand- receiver, and LA 10 line amplifier. crank worm -screw mounts for antennas. o;. ;n1

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TYRO

34 / MODERN ELECTRONICS / February 1985

www.americanradiohistory.com some pretty solid developments (Fig. 3). Once again, this is a block down - converter system, but this time with a twist: you can have LNB outputs at 440 to 940 MHz, 950 to 1450 MHz or 500 to 1000 MHz. Nominal gain is 60 dB, and gain flatness of the filter mixer and post amplifier is ± 1.5 dB. Operating temperature range is from -30 °to +60 °C. Its designers say that the Model BR101 is the first mass -produced uhf tuner made for the TVRO industry with a 440 -to- 940 -MHz i -f, 21 -MHz i -f bandwidth, and 8 -dB C/N threshold. It has a wide /narrow audio band selector, convenient channel scanning, an adjustable signal - strength meter, tunable audio sub - carriers, and a channel 3/4 modulator output. The Model LA lO line amplifier op- Fig. 5. ACT claims positive positioning of receive dishes via solid -state elec- erates from 5 to 950 MHz, at a gain of tronics (shown) and horizon -to- horizon trackers. 10 dB. As are the others detailed above, this is a 3.7- to- 4.2 -GHz C- band system, working with a built -in Polarotor II. tern. It offers 21- channel soft -touch drive, these weatherproof, lightning - Jim Morsillo of Radio Semicon- tuning, satscan, stereo -direct and protected, ball- bearing mounts (Fig. ductor had a number of comments on matrix ability, video and audio out- 4) for all types of dishes sell at the re- block system down- converters dur- puts, infrared remote control, exter- tail level for from $269.95 to $895, ing his Nashville show lecture. He nal audio and video inputs, baseband depending on antenna size and type predicted that only the 440 -to -940 output, LED function displays, au- and fancy or plebian tastes. Drive and 950 -to -1450 -MHz i -f ranges tomatic polarity selection, Dolby systems operate at either 24 or 36 would remain, since the former is noise reduction, etc. You can buy the volts dc (your choice), with tracking centered on the uhf TV band and the entire system, including 8 -ft. fiber- from 53 ° to 143 ° guaranteed. latter operates beyond it, avoiding all glass dish antenna, for $2095. Tracker control electronics is an- or most interference. However, the other phase of the mount picture, 950 -to -1450 -MHz system costs more with ACT (Actuator Control Tech- due to dual converters, does away Dishes And Mounts nology) claiming positive positioning completely with image frequencies, The home satellite industry is under- of receive dishes via solid -state elec- and works equally well with 4- or going more than considerable changes tronics (Fig. 5) and horizon -to -hori- 12 -GHz systems. Jim also recom- in both antennas and antenna mounts. zon linear -arm trackers. The trackers mended combining LNA and block Instead of 50 ° or 60 ° satscans, cur- have upper and lower overtravel lim- converter, eliminating a second met- rent and future designs are calling for its to prevent the dish from bumping al housing and cable connection, and azimuth sweeps from horizon to the ground and over -extended arm predicted that LNBs would sweep the horizon, manually or digitally con- damage. Solid -state switches (not TVRO industry with commercial spe- trolled, at prices that are decreasing Hall- effect sensors) and a slide -type cifications at consumer prices. constantly as competition and pro- potentiometer remote controller pre- Selling price of the Radio Semi- duction approach peak. cludes inconvenient digital marker conductor system wasn't available at An excellent example of this trend resets and resulting reprogramming. press time. comes from Tracker Mounts of Little This allows precise antenna position- M/A- Prodelin TI appears to be Rock, AR. Programmable or with ing at minimum cost and reliability. another block down -conversion sys- hand crank and positive worm -screw Retail price for the package is $349.

February 1985 / MODERN ELECTRONICS / 35

www.americanradiohistory.com 0.040 "- tolerance steel receptors that are specially bumped and dimpled to maintain exact measurements. These are 9 -ft. steel perforated arrays that have undergone five polystyrene li- quid baths in addition to a zinc bath that is baked onto the steel at 480 ° F. The whole overcoating procedure is for positive protection against rust. Marketer will be Janeil of Reseda, CA, and prices will range between $749 and $849. Advantages of the new antenna are said to be weight reduction and better cosmetic appear- ance, air drain, and heat dispersal.

Remarks

If they're made well and fully guaranteed by a reputable manufacturer, fiberglass, aluminum and steel dishes Fig. 6. Winegard Satellite Systems recently introduced a group of 6 -, 8- and 10 ft. should serve you well under most perforated-aluminum antennas with corrosion -resistant finish, extruded- alumi- conditions. Signal pickup feeds are num support, locking ribs. already proven, but the down -converter and receiver situations remain somewhat fluid, and lots of advances will take place here as competition The antenna outlook isn't as num antennas (Fig. 6) with corro- expands. sharply defined as the major manu- sion- resistant finish, extruded -alu- If you plan to attach more than one facturers hang in there with mainly minum support, and locking ribs. TV set to your satellite receiver, look fiberglass dishes. Newcomers gravi- They're lightweight, rugged, easy to into an orthogonal (dual- polarity- tate toward mesh and perforated assemble, and are shipped in four feed) block down -converter. If only metal arrays. "Backyard artists," on quarters (for the 10 -ft. dish), with a one TV is planned, then a simple the other hand, go the "hand layup" weight of just 92 lbs. Only 16 bolts LNA (low -noise amplifier) and the fiberglass route, that, if done im- and eight rim screws are required for usual 70 -MHz i -f and Polarotor will properly, results in delamination, assembly. Some models are supplied probably be sufficient for your bumps, peeling, and general deteri- in smoked -chrome, others in jet - needs -it will certainly be cheaper. oration for the unwary. But don't black finish. Companion receivers For all the foregoing, we do have despair; the big, reputable manufac- have remote controls, scan signal one word of caution. Although su- turers are in the business to stay. bargraph, skew (Polarotor fine tun- per-low -noise amplifiers will provide Even major names like Amplica and ing) control, 5.5 -to -8 -MHz audio an additional margin of signal -to- Avantek are now offering complete tuning, a video inverter, and a down - noise ratio with which to work, the systems of their own. Birdview, too, converter switch that allows ex- gain difference between the usual will soon be showing a 7 1/2-ft. ellipti- change without disturbing the receiv- 8 -and 12 -ft. dishes is at least 4 dB, or cal dish with offset feed, called a er. Down- converter /LNA i -f is the a power ratio of 2.5:1; so be guided SpoonTM, which the company pre- conventional 70 -MHz. Prices for 8- accordingly. In other words, where dicts will have better than 80% effi- and 10 -ft. systems, motorized or not, signals are minimal, you had better ciency and improved C /Ns of 1.5 dB. range from $2495 to $3495 complete. look at both 100 ° LANs, LNBs and Forerunner of new technology, Antenna -only manufacturer Jen- LNCs and a 10- or 12 -ft. receptor. Winegard Satellite Systems of Burl- sen Satellite Receiving Systems has Sorry to say, there are no cheap elec- ington, IA, is introducing a group of just spent $250,000 to bring a special tronic bypasses for adequate satellite 6 -, 8- and 10 -ft. perforated -alumi- form back from Ireland to produce signal flow. IYE

36 / MODERN ELECTRONICS / February 1985

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www.americanradiohistory.com nce upon a time, in a magic kingdom far away, there lived completely through the driver, any passengers, and all else that hap - a truly wondrous automobile. it was the first "no excuses, pestance had placed inside the wondrous machine. no apologies" automobile ever available, and was very When the grand vizeers were asked why the "BRAKE "pedal was popular among the princes and the populace alike. Alas, this other- not really a "BRAKE" pedal, but instead an evil and demonic de- wise stupendous machine had a single and very seriousflaw. A flaw vice, they offered two reasons. so insane that it could only have been placed there by a demented Some vizeers said that the multitudinous makers of hood orna- and wicked witch. ments and glove compartment door hinges did not want the drivers For, you see, this wondrous automobile had a large pedal on the bringing their vehicles to a quick and safe stop, since the hood orna- floor that was plainly marked "BRAKE. "Drivers of this automo- ments and glove compartment door hinges could then -horror of bile expected and assumed that, when this `BRAKE" pedal was unspeakable horrors -actually be inspected and possibly modified pressed, the automobile would be brought to a swift and safe stop, by the driver. without harm to the driver, or to any of the passengers, or to any Others said that there must be some protection to keep the driver cargo. from inadvertently and unintentionally pressing the "BRAKE" But this was nought to be. Forsooth, the "BRAKE " pedal was pedal if he did not, in fact, really want to bring this wondrous auto- really a magical pedal under a horrible spell. if the 'BRAKE "pedal mobile to a swift and safe stop. And indeed, a much older model of was pressed by itself, the automobile, the driver, and all contents got the same wondrous automobile, did have its "BRAKE" pedal situ- magically and instantly whisked back to the carriage house from ated where it could easily be mistaken for the horn ring. whence the trip began. Lo and behold, a certain driver of the wondrous automobile final- If a driver was foolish enough to press the `BRAKE "pedal at the ly decided he had more than enough of this male bovine excreta. same time he turned on the windshield wipers, the wondorous auto- He pulled out the old "BRAKE" pedal by its roots and threw it mobile did, in fact come to an immediate stop. But, alas and alack, away. Then, he replaced the magical "BRAKE" pedal with a real the immediate stop was so sudden and so violent that it destroyed the one that was able to swiftly and controllably bring this wondrous driver, passengers, and all contents of the magical vehicle. automobile to a safe and sure stop. Having done so, the driver Well, not really destroyed. For, you see, all that really happened is grabbed the nearest handy princess, drove off into the sunset, and that a pair of holes, five urflogs in diameter, got neatly punched lived happily ever after.

Upgrading Apple IIe's ROM Monitor

Here are fixes to change this model's restrictive monitor to an absolute old reset one, giving users an opportunity to unleash the computer's real power.

By Don Lancaster but in what a resident monitor should CAD /CAM programs, run special allow a user to do beyond what its cre- turnkey applications, etc. -I'll show A fable, you say? Only perhaps. ators think you should do. you how to design an improved mon- The wide -selling Apple IIe com- To got past the built -in restrictions itor, like those in older Apples before puter, likely the last Apple computer imposed by the machine's system the mass -market syndrome set in. with reasonable expansion flexibili- monitor, so that you can do all sorts With this ROM change, you'll be in ty, including socketed ICs, is not as of wonderful things -emulate a control, custom -modifying "Ap- tractable as adventurous users would "snapshot" card, replace the entire plesloth" to your heart's desire. like it to be. Its ROM monitor, where operating system with your own cus- Fortunately, the IIe monitor is res- the system's routines lie, has a fatal tom code for dedicated data -ac- ident in chips that can be swapped flaw of sorts. It's not in the code itself, quisition purposes, perform certain easily for 64K EPROMs. Along the

38 / MODERN ELECTRONICS / February 1985

www.americanradiohistory.com way I'll show you how to burn in the new EPROMs (which cost only SFFFF - about $6 each), that will replace the "OLD" original ones including putting in the MONITOR necessary code. The improved moni- $F800- tor will do everything the original IIe "EF" MAIN monitor ROM does, as well as open ROM new computing vistas for you. More- -or- BOARD LOCATION over, there is no "hole blasting" 2764 EPROM "E -10" done on a cold restart, which essen- AP PL E SOF T tially destroyed pages of code on a re- FIRMWARE set, taking away marvelous tools INTERPRETER such as stopping and inspecting. And if you keep your finger on the Open - Apple key for at least four seconds SE00o after a cold reboot, you will be dropped directly in the "old," more versatile monitor, awaiting your every machine -language command. "CO" The code version covered here ap- ROM MAIN plies only to the "original" IIe SD000- OR BOARD ROMs, shipped in most IIe's up to 1764 LOCATION 80 COLUMN EPROM "E -8" late fall of 1984. Separate code is re- FIRMWARE quired for either the "new" IIe Ile MONITOR ROMs or for the IIc. (See box at end ADD -ONS of article for details on getting code for versions.) You can tell you have Sc000 - an "original" IIe ROM if your scroll- ing appears disjointed and chunky. Fig. 1. Apple IIe firmware is held in a pair of 8K x 8 ROMs. Standard 2764 I call this new monitor a KREBF EPROMs can be directly substituted for the supplied,ROMs. monitor, named after the magic spell that "repairs willful damage" in In- sits in main board location E8, while There are four soft switches in- focom's Enchanter adventure game. the other is called the EF memory and volved. One pair handles only the Actually, we won't repair any willful sits in board location E10. memory area from $C300 to $C3FF damage ... we just won't do any in The traditional monitor area to and is used to make the 80- column the first place. I'll show you a pain- older Apple Its needed only the 8K firmware look like it is sitting in slot 3 less and fully automatic process for space from $F800 to $FFFF. This of the I/O space. The second pair of converting your own firmware into a area is still used as a monitor for the soft switches is used to switch every- form useful for EPROM program- IIe. To provide for the many new IIe thing else. These are called the ming. I will also give you the full new features, expansion hooks have been $CX00 switches. The X here can be a source code patch that will return ab- added to also allow use of the $C000- 1, 2, 4, 5, 6 or 7. solute control of your IIe back where CFFF memory area. The top half of the CD memory it rightly belonged in the first place. Since $C000 to $CFFF is in the I/O and the bottom three -quarters of the (This is also available ready -to -run on (input /output) area, special soft EF memory hold the Applesoft firm- a companion diskette, as well.) switches are used to pick either "nor- ware. This code is apparently un- mal" I/O or "monitor" use of this changed from earlier models, in the address space. Thus, IIe firmware. About The Firmware anything that "original" The "new" wants use of the "new" IIe monitor IIe and IIc firmware made some The stock Apple IIe has 16K of area must first turn off the I/O space changes to Applesloth, such as allow- ROM -resident firmware that sits be- and then turn on the CD firmware ing lower -case commands. tween $C000 and $FFFF. As Fig. 1 ROM. When you are finished using Older Apples used 16K ROMs that shows, this firmware is held in two the new monitor area, the CD ROM were not quite compatible with in- 64K read -only memories. One of must be turned back off and the I/O dustry standard 2716 EPROMs. One these is called the CD memory and space must be reactivated. enable pin was active -high on the

February 1985 / MODERN ELECTRONICS / 39

www.americanradiohistory.com ROM, compared to an active -low seconds. Real 2764s always come in a 2) Program- writes a single byte state needed by a 2716 EPROM. 28 -pin package, and are the only type into memory. While you could just change some of 2764 useable as a direct Apple 3) Verify- checks a byte just writ- jumpers around to do some short- monitor replacement. (Both Motoro- ten during programming. sighted 2716 replacements, you really la and Texas Instruments have their 4) Read -outputs a previously needed a small plug -in card to actual- own imitation versions of fake 2764's programmed data value. ly do the job right. that come in 24 -pin packages.) 5) Standby -does nothing, allow- Without the inverter, certain plug - ing other data bus uses. in cards could cause memory conten- These activities are handled by tion and hang up the machine. Quite About 64K Eproms four control lines, called VPP, a few articles on adding EPROMs to Figure 2 shows the pinouts for a real PGM, 0E, and CE. older Apples ignored this key point, 2764, along with some use details. To use an EPROM, you first have leaving you with a potential time To analyze any memory chip, to program it. Before you program it, bomb on your hands. Thus, swap- break the package leads down into you have to erase anything previous- ping for 2716 EPROMs did not get four groups: supply, address, data, ly stored in it. Erasure forces all of done much on older Apples because and control lines. Then analyze each the data bits to 1s, and all bytes to of the hassles involved. group as follows: $FFs. This erasing is done with a spe- Very fortunately, the 64K ROM Only a single + 5 -volt supply and cial ultraviolet lamp. firmware used in the IIe is directly ground are needed for normal read- The VPP (programming voltage) and exactly compatible with the stan- ing of the 2764 EPROM. Supply cur- line provides normal + 5 volts dc for dard 2764 EPROM. So, to customize rent is typically around 150 milliam- standby and reading. To program, things any way you like, you simply peres in the read mode. this line must be brought to + 21 to swap chips. The 2764 is a 64K memory that is + 24 volts. Earlier EPROMs did not The "CD" or "EF" chips in a IIe organized as 8K by 8. This means that not have this programming voltage may be directly replaced by 2764 there are 65,536 bit locations that are on a separate pin, which complicated EPROMs. In case you've tuned into programmable to 1 or 0. These bit lo- things. On some micro systems, it is a the microcomputer revolution late, a cations are arranged into word bytes simple matter to in- socket program a 2764 is a special "read- mostly" of 8 bits each. Thus, there are 8192 2764. Unfortunately, the stock Ap- memory that you can custom pro- different 8 -bit words. ple IIe does not have this capability. gram and reprogram yourself. You The address lines select which At any rate, leave VPP at + 5 volts to buy these for around six bucks. Erase word is to be written to or read from. do anything but program. Raise it to any old memory contents by using a Thirteen address lines are needed, + 24 volts to program. special ultra -violet lamp. You repro- since 2" = 8192. To select a particu- Incidentally, most 2764s can use gram the memory to suit your appli- lar 8 -bit word, the correct binary pat- either a +21- or a +24 -volt VPP cation, using either a programming tern of 1 s and Os is placed on the ad- programming voltage. Some older card for the Apple or a stand -alone dress lines. Internal address decoding 2732As and a few 2764As demand a EPROM programmer. inside the chip then selects the correct maximum of + 21 volts while being EPROM programmers are readily byte for reading or writing. Address programmed and will self -destruct available at any hacker's club if you lines always input from the micro- on the traditional + 24 volts. Check do not already own one. We will computer to the 2764. the data sheet for the exact brand you shortly see a sneaky way to program There are eight data lines, used to are using if there is any doubt. the 2764 on older burners that may route the contents of the addressed The PGM (program) line is a nor- not be directly able to handle such a byte to the microcomputer during a mal logic control signal. This one is large EPROM. read. The same lines are used to send grounded to program and is set to + 5 To customize your IIe, all you have the data to be written into the for everything else. to do is burn one or two 2764 EPROM during a write. Thus, the The aË (output enable) line is EPROMs and then swap them for the data lines input to the EPROM dur- brought low for a read or a write. A CD or EF memory they are to re- ing a write, and output from the high OE line disconnects the outputs place. That quick and that simple. EPROM during a read. of the EPROM, but leaves the chip There is one minor "gotcha" There are five possible activities addressed and fully powered. though: the 2764 EPROM used must an EPROM can be up to: The CE (chip enable) is used to be an Intel or Hitachi brand with 28 1) Erase -clears the entire memory turn on or off the entire EPROM. pins and an access time of 250 nano- when exposed to strong UV light. During a read, CE must be brought

40 / MODERN ELECTRONICS / February 1985

www.americanradiohistory.com THE IMP ILIME GETS HELD THE LIME GETS HELD RT - R READ. TO A READ GROUND® DURINO AT 500C OUAIMO AND AT 24 VDC DURING A WRITE. CT IS NORMALLY LEFT LIGHT LINES ARE WRITE. HIGH AT SUDC WHILE THE DATA STRAIGHT THROUGH AND ADDRESSES ME BEING SET CONNECTIONS. CLIPS TO POINT IN UP. WRITING IS DONE BY BRINGING BURNER THAT IS T THE Reel LINE GETS HELD TO GROUND FOR EXACTLY 50 - et DURINO A READ AND AT SUDC DURING A READ MILLISECONDS ANO THEN RETURNING A GROUNDED DURING R AND IS GROUNDED DURINO CII HIGH TO SVOC. WRITE . WRITE . A HIGH CI ALSO REDUCES THE (PIN OF U-I0 OM STANDBY CURRENT. I LIME IS BROUGHT THE MPC op CARO) THE= 1114001 -op LOW FOR R READ OR A WRITE. SUDC HERE TURNS OFF, OR DISABLES THE CHIP. RIMI- ORRBBER

24 0 0 0 PIN DIP 2764 (top view) PLUG ' a c c c c c g c g 0 0 0

SPOT l II SLIDE SWITCH X12 AO DO 07

HE I ADDRESS I LINES THE rEED LINES WILL Al2 8'O' Al21' PICK THE MEMORY CELL OUTPUT STORED VALUES 0 BE WRITTEN TO OR DURING A READ AND WILL READ FROM INPUT DATA DURING PROGRAMMING.

Fig. 2. Drawing shows how a 2764 is used. Fig. 3. Adapter for using 2764 in 2732 burner. low. During a write, CE is held high and then swap out the chips. For can can program a 2732, as most old- until an address is selected and data is more information on this and other er EPROM burners can, you can eas- input. Then CE is brought low for ex- memory chips, check into Don Lan- ily program a 2764 with this adaptor. actly 50 milliseconds to blast the data caster's Micro Cookbooks, SAMS You will find a two -position slide value into the EPROM. CE is then re- #21828 and #21829. switch on the adaptor. (Caution: Do turned high while the address not use a toggle switch here; it works changes for the next byte. A high CE Programming A 2764 "backward. ") Put the switch in the also greatly reduces the standby sup- LOW position to program the low 4K On An Older Burner ply power needed. of your 2764 as if it is a 2732. Then Apple chose to use the OE line as Many older EPROM burners cannot flip the switch to the HIGH position so an alternate chip -enable, since it is directly handle a 2764, and you won't you can program the high 4K of your faster. They were not in the least wor- find too many newer models avail- 2764 as if it is a separate 2732. ried about saving any supply power, able yet that do. Some of the nasties Our adapter is intended for use since they already had problems involved in physically upgrading an with the MPC "ap-ep" EPROM meeting the minimum power supply older burner include going from a burner peripheral card for the Apple current drain during the IIe redesign. 24 -pin to a 28 -pin socket, providing II or IIe. Certain details might Apple also permanently grounded that thirteenth address line, getting a change for other burners. the CE line and permanently held the PGM signal to the socket, and figur- Listed in the table are the parts you PGM line at + 5 volts, forcing any ing out how to stuff 8K worth of data will need to fabricate your adapter. 2764 plugged into the main board in- into the 4K I/O space normally avail- These parts should be readily avail- to a read -only mode. able on an Apple IIe. able anywhere, although you must be Thus, unless you want to do some We can bypass all these hassles by certain to use the type of premium major board carving, "in situ" pro- adding a fairly simple and easy -to- machine- contact DIP socket that can gramming of a 2764 EPROM in an use adapter to an older EPROM safely be plugged into one another. Apple IIe is not normally feasible. In- burner. This adpater will make the A schematic of the adapter is stead, you have to use an EPROM 2764 to be programmed look like a shown in Fig. 3. Note that this adapt- programmer or programming card sequential pair of older 2732s. If you or and the tools required to build it

February 1985 / MODERN ELECTRONICS / 41

www.americanradiohistory.com NOTE This edeptor is needed ONLY if you must burn a 2764 EPROM on an older 2732 5. burner You do NOT need this edeptor to replace e Ile ROM with a 2764 EPROM. I I Prepare a two inch length of bare 24 wire. Connect this wire to pin 14 of the 28 pin 2" socket, then to the nearest pin on the SPDT MINE slide switch, and finally to bent pin 22 22 = NINE I Place the 28 pin machined contact 29 PIN MACHINED DIP socket pins up and identify pin W CONTNCT I i Solder all three connections, using a spare 22. Carefully bend pin 22 towards OIP SOCKET DIP strip as a safety backup heetsink. Cut the center as shown IN 22 CUI TOM off any remaining wire Be careful not to VIE141 pin 14. Be sure you are using the long 28 pin get any solder on the tip of 1e 14 socket and not the short 24 pin one. Pins are numbered "backwards" from CENO usuel when viewed from the bottom SO° PPi//lr 6

2 11 Connect the 1N4001 silicon diode from

I I Push e single bare machined contact pin 1 to pin 28 of the 28 pin DIP socket socket pin onto pins 14 and 26 as shown. Be certain that the cathode ber of the diode goes to pin I. i I NOTE In any soldering steps, snap an extra DIP strip onto the cool end of the I I Make mechnicelly secure connections, pins being soldered. This keeps the pins but do not solder them just yet. aligned should the plastic soften.

I I Solder pin to socket at pins 14 and 26. DONT SET SOLDER ON THE PIN TIPSI

I I Take e two inch piece of red 4'24 solid 3. insulated wire and strip I/4 inch from II Push an I1 pin machined contact DIP one end and 3/4 inch from the other. strip Into pins 3 -13 as shown. NEO

I 1 Solder the 1/4 inch end of this wire to I I Push e 7 pin machined contact DIP the fer unused pin on the SPDT slide (FULL SIZE) strip into pins 15 -21 as shown switch. Loop the 3/4 inch end of this wire around pin 26 end then to the I I Push e 3 pin machined contact DIP diode leed coming from pin 28. strip onto pins 23 -25 es shown

I I Use en extra DIP Strip Osa heetslnk. end solder the red wire to pins 26, 28 and the diode lead Make sure you do not contact 27. 4. pin e. I I Carefully roughen one side of thé SPDT 44 SECOND

Slide switch and the bottom of the 28 I I Prepare two green insulated 24 wires MINE pin DIP pins 14 end 15. CLUE SWITCH two inches long by stripping 1/4 socket between IN POSITION Use very fine sandpaper or steel wool. SHOWN inch off each end Solder one end of the first green wire to the center I I Glue the switch to the 28 DIP socket pin SPDT switch terminal as shown using superglue or epoxy. Let FINSI sit overnight end then verify that the 13 1 I I Solder the other end of the first green switch still works. MINE wire to pin 2 as shown Use e dip strip

DON'T SET ANY GLUE INSIDE THE SWITCH ! as a heetsink in all soldering steps.

are needed only if you are having super glue, be careful not to get any resistor lead in place. Finally, cut trouble burning a 2764 EPROM on of it inside the slide switch. Carefully away all of the resistor except enough an older EPROM burner. All you test the switch after the glue sets. lead to form a small loop. need to do the actual upgrade on your You might later want to add a If you are using a different card or IIe is a programmed 2716 and a sim- 28 -pin ZIF (zero- insertion - force) a stand -alone burner, make sure you ple chip swap. socket atop the regular socket. De- find a place that is at ground during Figure 4 gives complete construc- pending on the pins on the ZIF, this writing and at + 5 volts during read- tion details for the adapter. It is very may plug in or have to be soldered. ing. Add a small wire hook to this easy to build, and should take all of Figure 5 shows you how to use the point so the grabber can access this

half an hour. Be sure to use an extra adapter on the MPC "ap -ep" card. signal. Also be sure that pin 1 will be machined- contact DIP socket or A very slight modification to the card at + 5 volts during read and at + 21 socket strip when soldering anything. itself is needed. You have to add a or + 24 volts during programming. This will keep the pins properly small wire hook to the top of pin one One detail. Note that the 2732 re- spaced and aligned should the plastic of integrated circuit U10. The easiest quires a VPP signal of ground for a soften. Plug this extra socket into the way to do this is to tin the top of the read and + 21 or + 24 volts for a cool ends of the pins soldered so it pin with a very small amount of write. The 2764 instead requires a straddles any pins to be heated. solder. Then bend a hook in the end VPP signal of + 5 volts for a read and If you use the optional epoxy or of a resistor lead. Reflow solder the + 21 or + 24 volts for a write. This

42 / MODERN ELECTRONICS / February 1985

www.americanradiohistory.com 9. 13.

1 Solder one end of the second green wire I Teke the remaining 24 pin machined contact

1 and the to pin of the 28 pin DIP socket DIP socket and identify pin 20 by inking the cethodde (ber) end of the power diode. SCUM plastic. PIN 20 1 1 Push bere end of the flying green wire Use a DIP strip es e heetsink. Do not the (FOLL SIZE) pin the solder the other end of this wire just yet Into the socket (TOM) end of 20 on 24 pin DIP socket. Solder wire to socket. 12 I I Align the sockets so that pin 14 of the 28 pin socket is above pin 12 of the 24 pin 24 PIN MNCMINE 10 The notches should be et the seme socket. SOCKET e 4 Inch stranded CONTACT DIP I I Prepare white 22 from each other. 25 end, but staggered wire by stripping 1/4 inch off each TOP VIEW end. Route this wire UNDER the bere 21 et and UNDER the wire wire pin 22 20 00 UNDER between pins 26 end 28. WHITE 44EXISTIMO 1 4. RRRRNOED WINES WIRE I I the end of the Solder "buried" I I Snap the two sockets together, being white wire to pin 27. Use e DIP sure the switch end is flush and the strip es e heetsink. notch ends ere staggered. SNAP TOSETHEN. THIS ENO FLUSH

I I Verify that pin 3 of the 28 pin socket goes to pin I of the 24 pin socket. r This completes the construction of your I EPROM adapter. 141

I I If you cere to, place a smell blob of silicon rubber sealant over all of the wires end the 121 beck of the switch. WHITE 15 STRANDED as a EPROM This will act strain relief WIRE I I Study the schematic of your burner end further support. Do not get end find a point that is grounded during e SOLDEN SECOND any glop in the switch. write and at 5vdc during a reed. Piece e OREEN WIRE TO SOCKET ENO OF smell wire hook or loop at this point in the PIN 20. burner circuitry.

On the MPC ep -ep burner, use pin I of U10, per the detail of figure five 12. 3 14NRE SURE COVEN WILL 1 I study the grabber to see how the wire gets SLIDE ON attached. Slide the cover of the grabber EFORE over the white wire. Doe triel assembly SOLDE AINSI Fig. 4. Detailed in these drawings and accompanying in- WITHOUT SOLDERING to make sure the grabber will go together properly. structions is the step -by -step procedure you should use to

Solder the grabber to the wire using e build an adapter for programming a 2764 EPROM in an minimum of solder. Then test the set up burning only 2732's. grabber to make sure it works properly. older EPROM burner for

read supply difference is the purpose Never try connecting or disconnect- Parts Table of the diode between adaptor pins I ing the grabber with a 2764 in place! and 28. If you are using an oddball As a special note to MPC "ap -ep" 1 -28 -pin machined -contact DIP socket make that no users, also be sure both S2 and S3 are EPROM burner, sure 1 -24 -pin machined -contact DIP socket

"hard" ground shorts this diode or a in their OFF position, pointing 1 -1I -pin machined -contact DIP strip supply line. towards the bottom of the card. 1 -7 -pin machined -contact DIP strip To install the adaptor, put it in the If your EPROM burner uses per- 1 -3 -pin machined -contact DIP strip 2 -bare machined -contact DIP pins existing 24 -pin ZIF socket so that the sonality modules, be sure to use the 1 -extra DIP socket for heat sink switch points away from the ZIF han- 2732 module and not a 2732A 1- miniature spdt slide switch dle. You might have to jiggle the han- module. 1- IN4001 silicon power diode dle slightly, center the adapter, and Due to lack of space, we're un- I- mini -grabber test clip then slide the locking handle home, able to present the entire article at 1 -1/4 -watt resistor, any value (see text) 1 -4 " white #22 stranded wire as there is a very slight "negative this time. Next month, we'll finish 1-2 " bare #24 solid wire handle with programming on an older burn- clearance" between the open I -2 " red #24 solid wire and the adapter. Then glomp the er, tell you how to capture, modify 2 -2 "green #24 solid wire grabber onto the wire hook. and test the monitor, and give de- optional -super glue, epoxy, or silicone ad- Be certain that the EPROM burner tailed instructions on how to install hesive. or card is configured for a 2732 burn! the "old" monitor in a Ile. £f

February 1985 / MODERN ELECTRONICS / 45

www.americanradiohistory.com Project No. 2 of a continuing series Circuit Design From Scratch

A hands -on approach to creating new circuits, including a practical car theft alarm you design.

By Jules H. Gilder signing the passive vehicle anti-theft alarm we've chosen for this installment. The greater sophistication, in Designing an electronic project terms of function implementation, requires careful planning and of the vehicle alarm requires more de- logical thinking. Though the tailed planning to produce a properly approach used in the first article of operating project the first time out. this series (November 1984 issue) was adequate for designing a simple The water pump controller, you'll dis- Setting Stage cover that it isn't sufficient for de- If you own a car, van or RV, or plan to buy one in the near future, pru- dence dictates that you make it as inconvenient as possible for a thief to steal it. Commercial anti -theft alarms are very expensive to buy and install, however, and many require you to arm them when you leave your vehicle, which is easy to forget to do. For an anti -theft alarm to be effective, then, it should automatically arm itself when the ignition is turned off and you leave your car and close the door. Because of the usefulness of the .r:

www.americanradiohistory.com+. -+'à- ...w .. r-, ' !.. passive alarm and the possibility of -Fable I. f'»+er Controller Operating Conditions reducing car insurance cost, it has been chosen as our design project this (A) (B) (C) (D) (E) reset door current ignition turn /keep time out. In the following pages, switch status output switch power on we'll show you how to design and on off build this alarm from scratch. Along 2 off closed off off off the way, we'll develop word descrip- 3 off open off off on tions, logic truth tables, and the de- 4,6 off open on off on sign equations that you'll use to im- 5 off closed on off on plement the circuits needed to pro- 7 off closed off on off 8 off open off on off vide the full range of alarm functions. 9 off open on on on

(1) Define The Problem No matter what anyone tells you, the (4) The alarm is to sound the vehi- cides to deliver it. Since this portion most important step in the design cles's horn intermittently for about 2 of the system is the key to making this process is deciding exactly what you minutes. After this, it must shut off a passive alarm system, let's tackle it want a circuit to do. Though this may and rearm itself to be ready for the first and define its operation in detail. sound obvious to you, just stating next intrusion. Additionally, you To begin with, from 3 above, the what you want may not be enough to want a provision for causing the vehi- system must be able to be switched get you started on the design. You cle's headlights to flash on and off in off at any time with a RESET switch. must fully define what is to be done step with the horn so that the vehicle The best place to implement the man- and when. I neglected to heed this can easily be located at night. ual reset function is in the power con- when designing the project presented (5) The system should have either a troller, since without power, the rest here, the result being that my first de- hidden switch or a keyswitch that can of the system won't work. Hence, the sign failed to operate properly. That be used to reset the alarm and also power controller must know the state failure is the reason why you're read- temporarily disable it when the vehi- of the RESET switch. If it is on, the ing this in the February 1985 issue of cle is given to a parking -lot attendant. output provided by the controller MODERN ELECTRONICS, instead of (6) The system should work in cars will always be off. Conversely, if the the December 1984 issue for which it that have door switches that connect RESET switch is off, sometimes the was originally intended. So my ad- to either chassis ground (the most controller will be on and sometimes it vice is: Write down exactly what you common arrangement) or to the will be off (more about this later). expect your circuit to do before you + 12 -volt line. Since the power controller is to be do anything else. activated by the vehicle's door (2) Flesh Design Following this counsel, let's list the Out Details switch, it must also know whether or features that should be incorporated Unlike the previous project in the not the door is open. Next, the con- into our vehicle anti -theft alarm: November 1984 issue, we cannot go troller must be provided with infor- (1) Automatic arming 15 seconds directly from initial project descrip- mation about the state of the ignition after the engine is shut off and the tion to logic design. We must first switch. From 1 above, the alarm is door is opened. If the door is not flesh out the details. From 1 above, armed (powered by the controller) opened (you don't leave the vehicle), we see that no system power switch is only if the ignition is off and the door the alarm is not armed. to be used. Instead, power is to be ap- has been opened. (2) Once armed, any door that plied automatically once the ignition There's one more factor that influ- opens and turns on the dome (cour- is turned off and the vehicle's door is ences the decision to provide power tesy) light triggers the alarm. opened. Thus, part of the alarm sys- from the output of the controller - (3) Once triggered, you have 15 tem is going to have to function as a whether or not the controller is cur- seconds to close the door and either power controller for the rest of the rently providing power. For this, start the engine or turn the ignition alarm system. there must be some feedback on the switch to the accessory position to What the above means is that the status of the output signal. disarm the alarm. Otherwise, the power controller portion of the cir- Now that we know the factors that alarm will sound and cannot be shut cuit must always be connected to the are going to control the arming of the off until the door is closed (with the positive side of the battery, while the alarm system, let's make a list of ignition on) or a RESET switch is remainder of the circuit is to receive what is to happen and when: closed (more about this later). power only when the controller de- (1)Whenever the RESET switch is

February 1985 / MODERN ELECTRONICS / 47

www.americanradiohistory.com Table 2. Power Controller Truth Table sented as the letter that heads the column but with a bar over it. (D) (E) (A) (B) (C) Therefore, the first our reset door current ignition turn /keep part of switch status output switch power on equation would be represented by the term for row 3: 1 o 2 o o o o E = ÁBCD 3 o o o o 1 because all elements in this row are O. 4,6 o o o 1 Continuing in the same manner for o o 1 5 rows 4, 5 and 9, we obtain: o o o 7 E = ABCD + ABCD + ABCD 8 o o o o 9 o o + ABCD. Since A is common to all terms, it can be factored out: E = A(BCD + C_D + BC_ is by the con- list gives a complete word de- on, no power provided This + matter the status of the how the power controller troller, no scription of Similarly, D can be factored out of other signals. (The rest of the items portion of our passive alarm is going the first three terms: list only if the RESET work. It has been put into easier - on this occur to E =A [D (BC +BC+ BC) +BCD]. is to- form in Table 1. The switch off.) understand Finally, factoring out Ti gives: (2) When the vehicle's ignition is line numbers in this table correspond E =Á {D [B (C +C) +BC] first turned and the door is still to the numbered items on our latest off + BCD }. it's easy to closed, power has not yet been ap- list. From this summary, Now we're going to use one of the table de- plied to the alarm. produce the logic truth that rules of Boolean algebra that states: (3) Once the door is opened (with fines the action of the system. X + X =1 (rule 1). the ignition off), for a fraction of a To convert Table 1 into the logic Using this rule, our equation be- second, the output is still off, but the truth table in Table 2, you simply comes: controller is going to turn it on. substitute 1 for on and closed and 0 E = 705(1-3 + BC) + BCD]. (4) After the initial fraction of a for off and open. The 1 was chosen to A second rule of Boolean algebra second, the ignition is still off and the represent the door's closed condition states: is door is open, but now the output sta- because in most vehicles the switch 5-c-+ XY = X + Y (rule 2). tus is on. not grounded when the door is closed Applying this to our equation, we (5) As the vehicle is exited and the and the voltage on the circuit side of get: door is closed, with the ignition off, the switch is at + 12 volts. E = A [D(B + C) + BCD] we want the controller to supply pow- Notice that in Tables 1 and 2 that We can now expand the middle term er to the rest of the circuit and con- one set of conditions is repeated (item of our equation and_get: tinue to do so. 4, 6). When we use the information E = Á(B D + C D + BCD). (6) Upon reopening the door, we contained in these tables, it is neces- If we now factor C out of the two want the system to be in the same con- sary to use this set of conditions only terms in the equation, the result is: dition as in 5 above. once. Consequently, we'll simply re- E = A[BD + C(D + BD)]. (7) If we close the door and turn the fer to this row as row 4. Once again, we can use rule 2 to ignition switch to on or "accessory" simplify matters: within about 16 seconds, the output (3) Power Controller Equation E= A[BD +C(B +D)] is still on for a fraction of a second, E= Á(BC +BD_+CD). but we want the system to turn if off. With the aid of a truth table, we can Factoring out theD term, we obtain: (8) After the initial fraction of a now write an equation that describes E= A[BC +D(B +C)]. second, the output of the controller the task the power controller is to turns off and remains off. perform (column E). As you already This is about as compact as the (9) To meet the conditions detailed know from the first installment of equation is going to get, however it is in item 3 of our original list of fea- this series, we use only those rows of expressed in terms of OR gates (the tures, we want the controller to con- the truth table that contain a 1 in col- addition) and AND gates (the multi- tinue to provide power with the door umn E. In addition, if an element in a plication). To minimize parts count, open, the alarm system armed (pow- column is a 1, that element is repre- we'd like to try to express the whole er provided by the controller), and sented as the letter that heads the col- equations in terms of NAND and the ignition on. umn. If the element is a 0, it is repre- AND gates. This can be done by us-

48 / MODERN ELECTRONICS / February 1985

www.americanradiohistory.com ing a third rule from Boolean alge- Schmitt trigger, we can minimize the Hysteresis bra, which converts an OR term to a number of gates needed and simplify NAND term: the circuit's design. o X + Y = X (rule 3). A Schmitt trigger provides a snap - o By setting X = B and Y = C, we ob- action output in response to a slowly tain: -_ changing input. Snap action is made 5a E = A[D(B C) + BC] and possible by the Schmitt trigger's hys- o

E =A[D(B C) + EC] . teresis, which is a dead band Applying rule 3 once more to the throughout which no change in out- equation, we get: put occurs. o Input voltage To understand what hysteresis is, E = A[D(B C) BC]. refer to Fig. 2. Notice that voltage at Fig. 2. By plotting input vs. output the input can increase substantially voltage of a Schmitt trigger, the up- (4) Convert The Equation without a change in output per and lower threshold points at To A Circuit causing voltage. At a point known as the up- which the device switches are ob- Since the last equation uses only per threshold voltage, however, the tained, as shown here. AND and NAND terms, we will stop output suddenly and rapidly changes. +v here and use it to build our power When input voltage decreases, there's controller circuit. A circuit that illus- a similar situation during which no trates how the various input signals change in output occurs for quite a combine to produce the final output while as the input voltage drops be- D is shown in Fig. 1. Although any logic low the threshold at which the device family could be used to implement initially switched high. The voltage this circuit, it is best for automotive can continue to decrease in this dead Fig. 3. The power-off timer uses only applications to use low- power, high - band until a second voltage -the one gate, a resistor and a capacitor to noise- immunity CMOS devices. lower threshold voltage -is reached. produce an output that is low for a Output voltage then rapidly drops. (5) Design The Timers given period of time and then goes The dead band and rapid switching high and remains there. From our original specifications, we make Schmitt triggers ideal for clean- know that three separate timing cir- ing up noisy signals and for use in cuits are required, one each for exit timing circuits. Except for these delay, entrance delay, and amount of special characteristics, Schmitt - time the alarm sounds. The system trigger gates are identical to other must also have an oscillator to pulse logic gates and can be used as replace- beep the horn, which is used here as ments for them. the alarm sounder. We're going to use two 4093 Fig. 4. The power -on timer provides It's possible to build the delay and Schmitt -trigger NAND gates in our an output voltage for a specified oscillator circuits with ordinary alarm. These quad 2 -input NAND - period of time and then goes low NAND gates. However, if we use a gate ICs function similarly to the will special kind of gate, known as a standard 4011 NAND gates used in the power controller. Some uses be in timing circuits, others will be as ordinary logic gates. Fig. 1. The power controller of the passive alarm is built around eight 2 -input Schmitt triggers can be used to pro- NAND gates, implemented with a pair of quad NAND integrated circuits. duce two basic types of timers. One is a power -off timer whose output goes low for a specified period of time and then goes high and remains high for as long as power is applied (Fig. 3). The other is a power -on timer whose output goes high for a specified period of time and then goes low and remains low for as long as power is applied (Fig. 4). The power -off timer in Fig. 3 con-

February 1985 / MODERN ELECTRONICS / 49

www.americanradiohistory.com sists of a single gate whose input has a power controller so as not to confuse resistor (R) to ground and a capacitor it with the main system power con- (C) connected to the positive voltage. troller. The timer power controller supply. When voltage is first applied MP must know three things before it can to the circuit, a very rapid input determine that an alarm condition change occurs for a fraction of a sec- exists and the horn should be ond as C charges. During this time, Fig. S. An astable multivibrator can C sounded. It must know if: the exist appears as a short be formed with a single Schmitt trig- circuit to the delay time has expired; a door has changing voltage, ger gate when a resistor is used to pro- applying a positive been opened; and the timer that con- voltage to the input of the Schmitt - vide the positive feedback required to sustain oscillation. trols how long the alarm is on has trigger gate. been activated. Since the is gate an inverter, its out- exponentially until it is great enough Let's see how this circuit deter- put immediately goes low. After the to trigger the input with a logic high mines when to turn on the alarm first fraction of a second, the voltage and force the output low. horn: applied to C is no longer changing Because Cis still charging when the (1) If the delay time has expired, (it's a constant dc voltage), so C input to the gate is triggered, how- the door is closed and the alarm is not blocks the flow of current. ever, current begins to flow through active, it should remain inactive. In the meantime, the positive volt- R once again, this time in the oppo- (2) If the exit delay time has age that initially got is through decay- site direction. Capacitor C now dis- passed, the alarm is not yet active and ing. When it drops below the low charges exponentially until its charge the door has been opened, the alarm threshold point, the Schmitt trigger's drops below the low threshold point, should be activated. output switches back to high and re- causing the cycle to repeat itself. Fre- (3) Once activated, the alarm mains that way for as long as power is quency of oscillation is calculated should remain on while the door is applied. The amount of time re- from the formula Fo = [1 /(1.4RC)], open. quired for the voltage to drop the to where Fo is in Hz, R is in megohms, (4) Even after the door is closed low threshold point is calculated and Cis in microfarads. and the alarm is armed, the alarm from the formula T = 0.7RC, where If a 2 -input NAND gate (Fig. 6) is should remain on for a full 2 minutes. Tis in seconds, R is in megohms, and used instead of a simple inverter, the (5) If the exit delay time has not ex- C is in microfarads. oscillator can be gated on and off. pired, the door is closed and the The Fig. 4 power -on circuit is very For example if the second input is alarm is not on, it should not be similar to the power -off circuit, ex- connected to the positive supply, the turned on. cept that the positions of R and C are circuit will oscillate as usual. How- (6) Even if the door is opened while reversed. In operation, the charge on ever, if the input is set low, by con- the exit delay is active and the alarm is is initially C zero and the output is necting it to ground or the negative off, the alarm should remain off. high. As the charge builds up, it side of the power supply, the oscilla- (7) If the exit delay timer gets stuck reaches the upper threshold point, tor will cease to operate and its out- in the active mode, the door is open causing the gate's output to switch put will go high. and the alarm is already on, it should low and remain low for as long as remain on. power is applied. The time constant (6) Powering The Timers (8) Even if the door is closed, as formula for the delay in switching is We now need a circuit to control the long as the alarm is already on, it T= 1.05RC. power going to the timers that, in should remain on. The only other circuit that requires turn, controls how long the alarm The last two combinations of in- a Schmitt trigger to operate well is the sounds. We'll call this the timer puts could not normally occur in astable multivibrator (oscillator) a shown in Fig 5. It uses only one gate, Fig. 6. If a 2 -input NAND gate is used to build an astable multivibrator, one resistor, and one capacacitor, the oscillator can be gated on by applying a positive voltage to the unused input. with resistor R providing the positive feedback required to sustain oscillation. When power is first applied to the circuit, C has no charge on it and the input is low, forcing the output high. As the output goes high, current flows back through R and starts to charge C. The voltage on C rises

50 / MODERN ELECTRONICS / February 1985

www.americanradiohistory.com properly operating system and can be Table 3. Timer Power Controller Operation ignored. included here as a They're (B) (F) (G) (H) safety factor should the exit delay door exit alarm turn or keep timer get stuck in the active mode. status delay timer on power on

Besides, it doesn't cost any more to 1 closed off no no implement, even if this capability is 2 open off no yes never needed. 3 open off yes yes A summary of the power timer 4 closed off yes yes 5 closed on no no in words, is controller's operation, 6 open on no no shown in Table 3. Applying the same 7 closed on yes yes rules used for Table 2, this becomes 8 open on yes yes the logic truth table shown in Table 4.

(7) Equation For The Table 4. Timer Power Controller Truth Table

Timer Power Controller (B) (F) (G) (H) door exit alarm turn or keep The next step is to convert Table 4 in- status delay timer on power on to an equation that, in its final form, 1 o o o implemented with only AND can be 2 o o o 1 and NAND gates: 3 o o 1 H =-3FG+ 1PG +BFG +BFG 4 o 1 +BFG_ 5 o o H = F(BG + BG + BG) + FG(B 6 o o o 7 1 _+ B) 8 o 1 H = F[ B(G + G) + BG] + FG H= Rift + BG) +FG H= F(B +G) +FG When multivibrator IC4D in Fig. 8 H= FB +FG +FG is not oscillating, its output is high. H= G(F +F) +FB Since we want the relay (K1) that op- H =G +FB erates the horn to be off when the H = GFB multivibrator is not oscillating, an in- The final equation allows the cir- verter is used to correct the signal. cuit in Fig. 7 to be implemented. To Fig. 7. The timer power controller is a This inverter (IC5B) also acts as a do this, however, we must have the lot simpler than the main power con- buffer for the oscillator. The signal is inverse of both the B and F signals troller and requires only three gates then fed to 2N2222 transistor Q3. available. The first is available from to provide all of the proper signals. Although the alarm duration timer the system power controller. By starts as soon as the door is opened, choosing the proper timer, in this we want the beeping of the horn to be voltage must be used. Hence, we use case, the power -off timer, we can delayed for 15 seconds to permit you a general -purpose npn transistor, generate the inverse of F directly, time to get into your vehicle, close the such as the 2N2222 specified. Of without an extra gate. door, and turn on the ignition. A course, just about any other general - As in the case with the system 15- second power -off timer control- purpose npn switching transistor will power controller, this circuit pro- ling the input to the multivibrator is do as well. duces a positive output all the time what is needed. This timer can be im- power is to be applied to the timer cir- plemented by ANDing the signals of (8) Finishing The cuits. Since neither power controller the 15- second power -off and 2 -min- can directly supply the current re- Timed Alarm Section ute alarm timers. Since NAND gates quired to power their respective cir- The voltage that turns on the gated are used, the output of a NAND gate cuits, the output of each is used to astable multivibrator that controls must be followed by an inverter to operate separate transistor switches the beeping of the horn must be posi- obtain the AND function. that can provide the required power. tive for the on and negative for the For the reset function, the signal Since the output signal is high off conditions. Therefore, the timer applied to the circuit must be high when power is required, a transistor used to control the duration of the when the switch (S2) is open and low that gets turned on by a positive alarm must be a power -on timer. when closed. This is most easily ac-

February 1985 / MODERN ELECTRONICS / 51

www.americanradiohistory.com PARTS LIST Solid -state devices DI -1N914 diode IC1,IC2,IC5 -4011 standard CMOS quad NAND gate IC3, IC4 -4093 Schmitt- trigger CMOS quad NAND gate Ql, Q2, Q3 -Npn switching transistor (2N2222 or similar) Capacitors

Cl, C3, C4- 47 -µF, 25 -volt electrolytic ® C2- 220 -14F, 25 -volt electrolytic Resistors (all 1/2-watt, 10 %) RI, R2, R4, R8 -330 ohms R3, R5, R6- 470,000 ohms R7- 27,000 ohms Miscellaneous K1 -12 -volt dc spdt relay S I -Dpdt switch S2 -Spst keyswitch or slide or toggle switch (see text) TS1 -8- or 10-lug screw -type terminal strip (see text) Perforated board and solder posts or, printed- circuit board; IC sockets; suitable enclosure; stranded hookup wire; spade lugs; electrical tape; machine hardware; solder; etc.

complished with the aid of pull -up resistor RI. When S2 is open, virtually no voltage is dropped across RI. Thus, both ends of the resistor have a high voltage and the output of IC2C is high. When S2 is closed, one end of RI is grounded and the input to IC2C drops to zero, as required. A single - pole, single -throw (spst) slide or toggle switch can be used here, but it would be prudent to use a more secure key- operated switch instead.

(9) Handling Both Types Of Door Switches The alarm was designed with the as- sumption that the door switch in the vehicle shorts to ground when the door is open. Since in some vehicles the switch connects to the positive side of the electrical system when the door is opened, we include a provision that will accommodate either ° '42 i condition -hence the inclusion of SI E O LL (Continued on page 82)

52 / MODERN ELECTRONICS / February 1985

www.americanradiohistory.com Project

FRONT C. REAR MASTER Ala y enhanced ..('-:/Z Ileceder STEREO

VOWEIit LEV LEVEL MONO LEVEL

"Surround- Sound" Enhancer Adding this accessory to your hi-fi system recovers ambience information from recordings and adds delay to provide realistic sound

By John H. Roberts Performing L R matrix recovery source. Therefore, most recordings before adding time delay cuts the ex- already contain significant amounts pense of using two complete chan- of ambience just waiting to be un- nels, with no deterioration of the am- locked. To unlock it, you need a Ambience-so-called "room bience information. Adding delay to special signal processor. sound " -is the missing in- the L R matrix corrects that sys- Two popular techniques to extract gredient that makes even the tem's localization problems. this ambience information from con- best stereo system sound flat and life- ventional recordings are time delay less when compared to live- perform- Some Background and L R matrix. Pure time delay, ance sounds. Over the years, various Artificial reverberation, generated not to be confused with delay gener- techniques have been devised and by either mechanical or electronic de- ated artificial reverberation, was dis- employed in consumer products to lays, offer some improvement over covered by E. Roerbaek Madsen, simulate or recreate the ambience of the unprocessed sound signals nor- who was searching for a way to dra- the live performance. To some de- mally delivered to the speakers of a matically improve audibility in con- gree, all have been successful. Until hi -fi system. However, even the most ventional recordings. now, however, few have offered the elaborate delay system requires ad- Some consumer hi -fi delay devices advantages of the Delay Enhanced justments to make the simulated re- L R Decoder described here. verberation match different record- What makes this Decoder project a ings, the result often sounding unnat- L± superior performer is that it uses two ural. Discrete and matrixed four - of the time -honored techniques that channel recording had the capability Amplifier have met with relatively large suc- reproducing was not of ambience but R cess. It offers both time delay and properly utilized and, hence, fell out L R matrix (ambience- recovery) of favor. capabilities in the same accessory. A certain amount of ambience is Fig. 1. TheDynaquadTML Rambi- Combining the two techniques re- automatically captured whenever a ence- recovery scheme places the rear sults in a system that works better microphone is located more than a speakers in parallel with the speakers than either alone. few feet away from any sound used in the front.

February 1985 / MODERN ELECTRONICS / 55

www.americanradiohistory.com "Uses two time -honored sound-enhancement techniques."

J3 A( Left J1 output R7 R20 Left R6 v J5 R2 51 100K 20K Center input R9 CENTER 10K output 20K R1A M 50K S2A VOLUME Os R3 R8 3K 2K ---1N R15 R4 C3 10K ° 3K ---)I 47pF J2 R5 Cl Right 10K 47pF R12 input R18 10K 2K R1B 50K S2Bp R13 s 20K R16 3K 20K 014 B< 3K -ÿ1 - S2C C2 47pF R17 M J4 51 Riput ^/Wr- output 1

C34 R70 C32 47pF 10K 1000 pF -(( R75 R69 R74 3K 10K I C2D 3K 7

R71 IC7B 1K

7 R72 100K R73 REAR R76 1K 51

J6 Rear/Surround output

Fig. 2. Entire schematic diagram of the Delay Enhanced L -R Decoder, minus its built -in power supply. Arrowed letters in each part match up with the same arrowed letters in other parts (A goes to A, B to B, etc.). Numbers shown in small boxes are voltages that can be measured with a good circuit, provided here in case you have to troubleshoot

of the late 1970s were based on the known as DynaquadTM, was a pas- reflected sounds arrive from various Madsen principle. This approach re- sive system that simply connected a odd angles with relatively large time produced a delayed version of the pair of rear speakers differentially differences between the two micro- front signal through additional across the "hot" or + terminals of phones. speakers located off to the sides or the left and right output channels of By subracting the output of one rear of the main front speakers in the an amplifier (see Fig. 1). This system microphone from the other, the al- listening room. It is interesting to operated under the principle that most identical sounds would cancel note that this technique also works sounds coming directly from an or- out, leaving predominantly am- with mono recordings. chestra arrive at both microphones bience. This system improved the L -R matrix, perhaps better almost simultaneously, while room- ambience situation quite a bit, but it

56 / MODERN ELECTRONICS / February 1985

www.americanradiohistory.com +15V tion problem is the same mechanism R52 R50 R48 R /8 that caused it in the first place, name- 100K 180K 510 10 ly the (see C19 Hass effect "Haas Effect" LFD2 R51 IC6 T 100yF box). 1K R53 NE555 2K In the passive L -R system, sounds from the rear speaker will 2 5 I C17 R4/ 108F reach you before the sounds from the 510 R45 C21 C20 front speakers because they are f 10K 510pF closer. Because the Hass I of effect, C> your brain will attempt to lock onto 1 C6 R38 1pF 680K these rear Mh sounds, causing you to C7 R44 hear false localization. IC5 846 2700pF 1K R 5108 R31 R32 D1 10K Delaying the sounds being fed to 120K 39K 1N914 618 the rear speakers by 20 to 30 millisec- 10p F o< R34 onds will ensure that the sounds from 51 the front speakers will always arrive R36 R35 at the listener's position before the 22K 22K 854 100K sounds from the rear do. In fact, when properly adjusted, this project 862 C22 C.9 3K 510pF should make it so that you never ac- 15V 10p F Y tually hear the rear speakers as dis- a. C8 R63 R55 crete sound sources. What you will 100K 108F 10K R43 ir-17-46 get, then, is ambience that simply C16 R42 C23 "surrounds" you as you listen. 1pF 1V 100pF The L -R matrix plus delay works equally well with a wide range of program sources, including many that R77 < IC3B z.s were not originally recorded using R37 stereo microphones. 1K

11 9 R38 C10 About The Circuit 39K 108F The schematic C14 diagram for the am- 13 .1µF R41 C13 R40 R39 (,17 bience- recovery system is shown in IC4 5.1K .018F 5.1K 22K T OlF three parts, in Fig. 2A, B and C. The N c15 system is designed to work with a 18F C78 wide range of both mono and stereo 1NF R58 C26 R59 Ií56 1,24 program sources. The output of the 5.1K .018 F 5.1K 22K 1;.F ambience /surround channel, avail- C28 R59 C27 C25 able at J6 in Fig. 1C, offers a full 18F 39K 108F 01 p 12 -kHz bandwidth. (Listening tests A I. have revealed that the 6 -kHz bandwidth used in past designs was inade- quate for best ambience extraction from CD and other high -quality re- suffered from poor front imaging power amplifier. Additionally, peaks cordings.) and localization. That is, sounds oc- occurring in only one channel may In addition to the normal L -R + casionally appeared in the back that upset the protection circuitry of the delay, or surround, mode, a stereo were not supposed to be there. other, which must then sink the full synthesizer is built in to enhance A note of caution: If you wish to current being sourced, even if it is sit- playback of monophonic program experiment with the passive L -R ting at 0 volt. sources. Jacks J3 and J4 in Fig. 2A matrix, keep in mind that the rear In the Delay Enhanced L -R De- provide the outputs for both normal speakers will be in parallel with those coder presented here, the mechanism stereo and synthesized stereo, the latin the front and may present an unac- that allows the time delay to cure the ter when a mono source is connected ceptably low impedance to your passive L -R matrix's front localiza- to input jacks JI and J2 and switch S2

February 1985 / MODERN ELECTRONICS / 57

www.americanradiohistory.com PARTS LIST Resistors (all 1/4-watt, 5%): S1 -Dpdt push -push pc -mount switch R2, R5, R12, R15, R25, R26, R45, S2 -4pdt push -push pc -mount switch Solid -State Devices R46, R67 thru R70- 10,000 ohms, T1 -28 -volt, center -tapped transform- D1, D2 -Not used carbon -film er D3 thru D6- 1N4002 rectifier diode R3, R4, R13, R14, R22, R23, R62, Miscellaneous: D7 -1N914 signal diode R74, R75, R77 -3000 ohms Printed circuit board; sockets for ICs; ICI, IC7- NE5532 or TL072 dual op R6, R9, R16, R19, R27, R28, R46, suitable enclosure; line cord; strain amp R66- 20,000 ohms relief; control knobs; panel lens for IC2, IC3- TL074CN quad op amp R7, R17, R24, R34, R76 -51 ohms LED1; machine hardware; hookup IC4 -NE572 dual compander R8, R18, R53 -2000 ohms wire; etc. IC5 -R -5108 2048 -stage ASR (Reticon) RIO, R11, R78 -10 ohms IC6 -NE555 timer R21, R37, R44, R49, R51, R71, R73- Note: The following items are available IC8 -78M15 + 15 -volt regulator 1000 ohms from Phoenix Systems, Inc., PO Box IC9 -79M15 - 15-volt regulator R29- 27,000 ohms 628, Manchester, CT 06040 (tel. 203- LED1, LED2- Light- emitting diode R30- 36,000 ohms 643- 4484): No. P- 250 -DL complete R31- 120,000 ohms kit of parts for $179.00; No. P -250 -B Capacitors R32, R35, R36, R39, R56- 22,000 ohms etched and drilled pc board for Cl, C2, C3, C34- 47 -pF, 10 %, disc R33- 680,000 ohms $19.00; No. P -250 -T 28 -volt, c.t. pc- C4, C7- 2700 -pF, 5 %, polystyrene R38, R59- 39,000 ohms mount transformer for $7.00; No. C5, C23- 100-pF, 5 %, polystyrene R40, R41, R57, R58 -5100 ohms R -5108 Reticon 2048 -stage ASR IC C6, C11, C14, C16, C24, C28, C31- R42, R43 -1 megohm for $30.00; NE5532N dual op amp 0.1 -SF, 5 %, polystyrene R47, R48 -510 ohms for $2.25; TL074CN quad bi -FET op C8, C9, C10, C17, C18, C27, C38, R50- 180,000 ohms amp for $2.50; NE572N dual com- C39- 10 -µF, 35 -volt electrolytic R54, R55, R64- 100,000 ohms pander for $3.25; 78M15 regulator C12, C13, C25, C26- 0,01 -µF, 5 %, R60- 62,000 ohms for $1.50; 79M15 regulator for $2.50; polyester R65- 18,000 ohms No. P- 2X5OKB dual 50,000 -ohm, lin- C15, C29 -1 -µF, 25 -volt electrolytic RI-Dual 50,000 -ohm, linear -taper po- ear -taper potentiometer for $2.50; C19- 100 -µF, 16 -volt electrolytic tentiometer No. P -100KB 100,000 -ohm, linear - C20- 0,01 -µF disc R20, R52, R72- 100,000 -ohm, linear - taper potentiometer for $1.00; No. C21, C22, C33- 510 -pF, 5 %, polyester taper potentiometer S -1 dpdt pc -mount switch for $1.00; C30- 0.005 -µF, 5 %, polyester R63- 10,000 -ohm trimmer potenti- No. S -2 4pdt pc -mount switch for C32- 1000 -pF, 5 %, polystyrene ometer $1.50. Add $1.00 S&H for orders of C35, C36- l000 -µF, 35 -volt electrolytic Other Components: less than $10.00, $2.00 on COD or- C37, C40 thru C49- 0,1 -µF disc Fl -'/ -ampere pigtail fuse ders. Connecticut residents, please C50- 0.022 -µF, 600 -volt disc J1 thru J6 -Phono jack add 7.5% sales tax.

MONO. L - newest ASR is set to Also, an + R, front This circuit uses the Specifications center fill, output is provided at J5 in integrated circuit, the R -5108 from impedance 10k ohms or greater Fig. 2A, for use in small movie screen Reticon, to extract ambience signals Input Output impedance 50 ohms applications and in hi -fi setups as a from stereo sources. This device, Maximum output mono feed to a subwoofer. shown as 105 in Fig. 2B, has 2048 into hi -fi load 8 volts For convenience of setup and use, stages of delay, which is twice as long into 600 ohms 7.5 volts the circuit includes a master volume as the popular SAD -1024 and half as Gain (each output) +6 dB to full off 5 to 30 ms, adjustable in Fig. 2A) and separate long as the SAD -4096. This new chip Delay time control (R1 THD +N level controls for the front -center has the biphase clock drivers and out- direct <0.01%, 20 Hz to 20 (R20 in Fig. 2A) and surround (R72 put sample- and -hold circuit built in- kHz in Fig. 2C) outputs. Both outputs are to a smaller chip that is housed inside delay 0.5% nominal, 100 capable of boost and cut relative to a compact 8 -pin DIP package. Hz to 10 kHz the master volume control. Hence, it Input and output filters, tuned for Noise (IHF A) direct < - 100 dBV is a simple matter to correct for dif- -3 dB at 12 kHz, condition the delay -91 dBV ferences in sensitivity between the audio in the surround channel to Frequency response front and rear speaker systems. Once avoid sampling rate aliasing and to direct dc to 20 kHz +0/ relative gains are set, the level con- smooth out the output waveform. - 0.25 dB Hz to 12 kHz master volume An NE572N, 1C4 in Fig. 2B, com- delay 20 trols track the control ±3 dB for routine system level changes. panding noise -reduction chip is used

58 / MODERN ELECTRONICS / February 1985

www.americanradiohistory.com "Simulates stereo sound from mono sources." around the delay chip for noise -free natively, you can purchase a ready - The Haas Effect performance with even the most dy- for- installation board from the Haas, an early researcher into psycho - namic sources available. The source given in the Parts List. Which- acoustics, characterized how we per- NE572N is an improved version of ever way you go, you will note from ceive and localize sounds. He determin- the popular NE570. the components -placement guide in ed that, to avoid being confused by the NE555 timer IC6 in Fig. 2B gener- Fig. 5 and the photo of the interior of echoes caused by reflections when try- ates the timebase for the system. The the project in Fig. 6 that all compon- ing to localize the direction from which frequency of this time base controls ents except the various input and out- a sound is coming, the brain ignores all how long an audio sample takes to put jacks mount directly on the cir- but the first sound it "hears" for a small work its way through the ASR. Po- cuit board. fraction of a second. All reflections arriving during this time the tentiometer R52 provides the means There is nothing critical about as- period, called Haas Fusion Region, are fused into the for adjusting the clock frequency to sembly, except that you must care- first sound, thus increasing its apparent vary - the system delay time. High fully observe the polarities and orien- loudness. slew -rate op amps are used through- tations of the integrated circuits, As a result of this "fusion," you per- out the system to deliver maximum diodes, light- emitting diodes, and ceive one louder sound coming from the audio fidelity. electrolytic capacitors before solder- direction of its first arrival. Reflections The power supply for the system is ing them into place. Sockets are rec- and echoes arriving after fusion, de- shown in Fig. 3. Note that this full - ommended for all ICs, though you layed by 20 to 30 milliseconds, are once wave bridge circuit provides full reg- can, if you wish, install these devices agains perceived as separate sounds. ulation of both the + 15- and directly on the pc board and solder Their density and rate of decay contain - 15-volt buses. The schematic also their pins to the copper pads. information that your brain uses to shows the pins to which the buses Approach assembly logically. gauge the nature of the acoustic space you are occupying. connect on the ICs. Start component installation with the lowest -profile devices first and work Construction your way up to power transformer Next, install the resistors and diodes, Tl. That is, install first the jumper followed by the IC sockets (if you Owing to its complexity, it is highly wires (indicated by the Js in Fig. 5) us- have decided to use them) or the ICs recommended that you assemble the ing bare solid hookup wire, except themselves, trimmer potentiometer delay system's circuit on a printed - between pin 1 of IC2 and the junction R63, and the low-profile capacitors. circuit board. You can fabricate your between R16 and R69 and between Before installing LEDI, trim its own board, using the etching -and- pin 14 of IC3 and C31, both of which leads to 1 11 " long, taking care to re- drilling guide given in Fig. 4. Alter- must be insulated solid hookup wire. member which lead is which (it is best

D3 1N4002 810 H T1 10 IC8 > 15V o 78M15 S1A D4 1 C35 C38 C40 1N4002 1000p 2 10µF 15F

28 V C T. C36 C37 C39 C41 D6 1 var. T1000µF .1NF 15F 1N4002 10p IC9 > 15V 511 79M15 10 o N SIB D5 1C4 8 1N4002 NOTE: I NE572 111 Var C42 thru C49 = 0.1µF. w -15V I C42 I C44 I C46 7Ic C48 1 C43 T- c»; C47 C49 -15V> T Fig. 3. This is the power supply, showing full regulation of the + 15- and - 15-volt lines. The lower portion of the diagram shows power connections to ICs.

February 1985 / MODERN ELECTRONICS / 59

www.americanradiohistory.com dude electrolytic capacitors C35 and e Dolby Soúnd Movies C36 and transformer TI in the Movie sound tracks are usually record- power -supply section and controls ed in discrete left, right, center (front), RI (MASTER LEVEL), R20 (FRONT and surround (rear) channels. Special (DELAY), R73 effects, like earthquake sounds, can LEVEL), R52 and bring the count up to six discrete chan- (REAR LEVEL). Temporarily set aside nels. When these movies are mixed the pc board assembly. down to the ordinary two -channel As with the pc board, you can fab- stereo track format, the center channel ricate your own low -profile enclo- is matrixed onto the left and right chan- sure or purchase it ready -to -use, in- nels in- phase, while the surround chan- cluding all machining and labeling, nel is matrixed onto the left and right with the complete kit of parts from channels out -of- phase. the source given in the Parts List. If When this stereo mix -down is played you decide to make your own enclo- back througha stereo system, the most- sure, make sure you drill the holes for ly dialog center channel is projected from the left and right speakers at equal the controls, switches, LEDI, input volume and appears localized between and output jacks, and the line cord in the two. The surround signals also come the proper locations. Use the circuit - out of the left and right speakers. But board assembly to take all measure- because they are out -of- phase, they ap- ments for this operation. pear to take on a diffuse quality with Once machined, the enclosure wider apparert separation. If this stereo should be spray painted and, when mix -down is played back through a the paint completely dries, labeled. If monophonic system, the surround sig- you use a dry- transfer lettering kit, nal cancels out. apply two or three light coats of clear installations reduced Theater use spray lacquer to the front and rear bandwidth, ( -3 dB at 6 kHz), Dolby B panels to protect the lettering. Be noise reduction, and logic separation enhancement on the surround channel. careful not to make the lacquer too This is done to accommodate the signif- thick or runny or the lettering will lift icant number of movie -goers whO must off and dissolve. sit directly beneath one of the surround When the enclosure is ready, in- speakers and would not otherwise re- stall the input and output jacks on the ceive an acceptable balance of front to rear panel and wire together all surround signals. ground lugs with bare solid hookup wire. Then pass the free end of the line cord through its hole and secure Fig. 4. This reduction of the actual - it in place with a plastic strain relief. size etching -and- drilling guide for (If you prefer, you can line the hole the pc board requires 2 x blowup. with a rubber grommet, pass the free to somehow mark the cathode lead end of the line cord through, and first one and then the other free end for easy identification). After install- knot it about 7 " from the free end.) In of the line cord. Make sure that all ing and soldering the lead to the cop- any event, leave 6 " to 7 " of loose wire fine wires are twisted into the bun- per pads on the board, bend the leads with which to work. dles. Then lightly tin each bundle first back away from the lip of the Retrieve the pc -board assembly with solder. Slip these wires into the board and then forward, about half and install and solder into place seven holes provided for them in the pc way along their lengths. When you separate lengths of hookup wire, or board, solder them to the copper are finished, the LED should be use a seven -conductor, preferably pads, and trim away any excess. about Y. " above and its body parallel color- coded, ribbon cable to the ap- Carefully align the shafts of the with the board's surface. Be careful propriate points on the circuit board. controls and the buttons on the not to flex the LED's leads too much Make the wires long enough to reach switches with their respective holes in or they will break away from the their respective jacks, plus some the front panel and slide the board in- device's body or the board. slack, when the board is in its mount- to place. Start hex nuts onto the con- The largest components should be ing location inside the enclosure. trol shafts but leave them quite loose. mounted last on the board. These in- Twist together the fine wires in Tilt the board upward from the rear.

60 / MODERN ELECTRONICS / February 1985

www.americanradiohistory.com All input and output jacks mount on the rear wall of the enclosure. The switches, controls and LED mount on the front panel. All other components mount on the pc board.

cuit board to the appropriate jacks about the 30 -ms position. You can on the rear panel. optimize the delay time for your room by listening to a recording with Hookup and Use impulse -type sounds, like record scratches (they are good for some- The delay system is best connected after all). When the delay time between the outputs of a preampli- thing, is set for too long a duration, you will fier and the inputs of a power ampli- hear discrete repeats or echoes. If it is fier. However, it can also be used ef- set for too short a time, the image will Fig. 5. When installing components fectively in a tape- monitor loop. to the rear speaker. When the on the pc board, be certain to orient The rear speaker system and its shift setting is correct, the rear speaker will them as shown. driving amplifier need not be as aurally disappear as an actual sound powerful and wide ranging as the source. Using Vs " spacers and No. 4 machine front speaker systems and amplifier. hardware, mount the board to the Typically, an amplifier for the rear floor of the enclosure. Before tight- source need not have more than 25% In Closing ening any hardware, make certain to 50% of the power of that used up The project described above will ex- that the buttons on SI and S2 work front. The rear speaker need not be tract ambience from any stereo pro- without binding. This done, tighten critical in performance, nor need it be gram source and deliver spectacular the board mounting screws and the matched to the speaker systems you "surround sound" effects from ste- hex nuts on the controls. Then press a use for the front, since the surround reo- encoded movies. At least one of red panel lens into the remaining hole channel rolls off above 12 kHz and the new stereo TV programs, NBC's in the front panel and carefully push very low frequencies tend to be re- Miami Vice, uses surround sound; LEDI into the lens. Install knobs on corded in -phase and, thus, are sup- others are expected to follow. In the the front -panel control Shafts. pressed in the surround channel. mean time, you can switch in the ste- Using Fig. 2 and Fig. 5 to guide To set delay time, begin with the reo synthesizer for the old- fashioned you, connect the free ends of the DELAY control set to its midpoint monophonic TV programs and still wires coming from the printed -cir- position (straight up). This will be enjoy enhanced sound reproduction. NE

February 1985 / MODERN ELECTRONICS / 61

www.americanradiohistory.com I NOTEBOOK/II/II

Experimenting with the Analog Comparator

By Forrest M. Mims III the output of the amplifier to swing ever, you can use a commonly avail- wildly from ground to the maximum able op amp, such as the 741, in a possible positive or negative voltage comparator mode simply by leaving In this digital age, analog (linear) extreme. When used in this fashion, out the usual feedback resistor. Fig- electronic circuits are sometimes the operational amplifier is consid- ure 1, for example, shows a basic considered obsolete. Of course, ered an analog comparator. comparator demonstration circuit nothing could be further from the The comparator has an amazing made from a 741 integrated circuit truth. Indeed, analog circuits can number of applications. Because of and several resistors. perform many tasks for which digital the comparator's two -state (on /off) In operation, resistors R2 and R3 circuits are totally unsuited. And, us- mode of operation, many of its appli- form a voltage divider that places ing just a few components, they can cations are digital in nature. In this half the supply voltage, or 4.5 volts, perform some tasks that would re- column, I'll explain how the compar- at the 741's inverting ( -) input. This quire highly complex digital circuits ator works and provide some sample is called the reference voltage. Poten- like programmable microprocessors. application circuits with which you tiometer RI functions as an adjust- One of the key analog circuits is the can experiment. able voltage divider that delivers a operational amplifier. This circuit is variable voltage to the noninverting amplifier ( + ) input of the 741. This voltage is a two- input, differential The Basic Comparator that uses a feedback resistor from its called the input. output to one of its two inputs to con- Many different analog comparator When the amplitude of the input trol the circuit's voltage gain. When integrated circuits are available com- voltage is below that of the reference, the feedback resistor is omitted, even mercially (in future columns I'll de- the output of the 741 comparator is a very small input signal will cause scribe some of them). Often, how- low (near ground). Therefore, the

Fig. 1. Shown here is a basic comparator demonstration circuit. Fig. 2. This is an adjustable light -dark detection circuit. +9

PIEZO ALERTER Ry (RADIO SHACK R2 `i"?OR 1DK 273-065 oR o PC I. siMILAR) (SEE TEXT) RL LED SOK V 7,11

791

look loo K R3 10K

62 / MODERN ELECTRONICS / February 1985 www.americanradiohistory.com FREE famous LED is switched on. When the input voltage tech catalog rises above the reference, the Iii h output of the 741 suddenly switches More than just a catalog, on, rising to near the positive supply a trustworthy guide to voltage extinguishing the LED. new in If the input voltage is made very what's computers close to the switching threshold, the and electronics. 741 may oscillate in an unstable fash- Metal For many years, the Heathkit cata- ion by rapidly and unpredictably Detector log has been a guide to new, excit- switching on and off. But, practically ing kit products for people like you to build. To enjoy. Learn from. And speaking, the comparator output is save money. Triple -Trace either full -off (ground) or full -on Oscilloscope What sets this catalog apart is (near the positive supply voltage). Computerized its range of high quality prod- Weather Station ucts and accurate informa- Note that the inputs of the compar- tion on every product. ator are designated inverting (pin 2) Ham Radio Over 450 interesting Transceiver items - Computer and noninverting (pin 3). You can re- hardware and soft- verse the operation of the circuit in ware Robots Preci- sion test instru- Fig. 1 simply by reversing the in- two ments Computer- puts. Be sure to keep this in mind Microprocessor ized weather when you experiment with the fol- Trainer & Course instruments Solar hot water lowing circuits. Automotive and home energy Real Time Spectrum Analyzer products Adjustable Light -Dark With Heathkit, you'll dis- Security de- cover a special pride of ac- vices Color Detector Most complishment by creating TVs Video re- that is Accurate hand -built quality Clock corders, cameras The basic circuit in Fig. 1 may seem uniquely yours. and acces- simple, but it can readily be adapted You'll build your kit 40- Channel sories Stereo for many applications. Figure 2, for with confidence too, know- Scanner components by our example, shows how ing you're backed Amateur radio gear to use the basic simple promise, "We won't Electronics courses circuit as an adjustable light -dark de- let you fail:' leading from basic tector. This circuit can be used to sig- If you don't have the latest electronics to high tech. nal the arrival Heathkit Catalog, the whole of dawn (or dusk) and family is missing some- to provide a warning when a refriger- thing great. ator door has been left open. It can also be used as a simple break -beam object detector. Though the circuit uses a piezoelectric buzzer or alerter, an output relay can be included to HERO' Robot IBM PC- -"- "` control an external motor, lamp or Compatible other device. Computers The circuit's light detector is a low - r 1 cost, but highly sensitive, cadmium - Heath Company, Dept. 079 -262 Send NOW Benton Harbor, Michigan 49022 sulfide (CdS) photoresistor. The cir- for your cuit activates the alerter when the FREE Please send me the latest Heathkit Catalog Free. photoresistor is illuminated by even a Heathkit Name very low light level. After a simple Catalog modification is made, the circuit will Address trigger the alerter when the photode- State tector is dark. In either case, the cir- Heathkit City cuit consumes only about 0.5 milli- Heath Zip Company A subsidiary of Zenith Electronics Corporation CL-777C L CIRCLE 77 ON FREI: INFORMATION CARD February 1985 / MODERN ELECTRONICS / 63

www.americanradiohistory.com ELECTRONICS NOTEBOOK ...

The alerter in Fig. 2 can easily be replaced by a relay that can control

external lamps, motors and other de- .. vices. The circuit in Fig. 3 shows how. Adjustable Temperature Detector The photoresistor in the Fig. 2 circuit can be replaced by a thermistor to transform the circuit into an adjustable- threshold, temperature- sensing alarm. Properly calibrated, the circuit can function as a freeze detector. In operation, the output from the comparator at pin 6 is connected via R3 to QI, which functions as a switch that turns on and off a low- voltage relay. When the comparator's output is high, QI switches on and, in turn, allows current to flow through the relay coil. Transistor QI can be a 2N2222 or any other general -purpose silicon switching transistor. The relay is Radio Shack's No. 275 -004. Some electronics parts suppliers You mail -or- Fig. 3. An adjustable -threshold temperature-controlled relay. stock thermistors. can der purchase them if they are not available locally. Check the ads in ampere in its standby mode and 3. The alerter will then be actuated. this and other electronics magazines. about 4.5 milliamperes when the When the light level at the sensitive Some of the many thermistor manu- alerter is sounding. surface of the photoresistor is de- facturers include Keystone Carbon Comparing the two circuits, note creased, its resistance is increased. Co. (Thermistor Division, 1935 State that the photoresistor in Fig. 2 has re- Indeed, the resistance may reach a St., St. Marys, PA 15857); Fenwal placed R2 in Fig. 1. Therefore, the million ohms or more when the light Electronics (63 Fountain St., Fram- photoresistor and RI in Fig. 2 form a level is very low. When this occurs, ingham, MA 01701; Thermometrics, light- dependent voltage divider. Po- the voltage at pin 2 approaches Inc. (808 U.S. Highway #1, NJ tentiometer R2, which forms a sec- ground. In any case, when the light 08817); and Omega Engineering, ond adjustable voltage divider, per- level falls to a point where the voltage Inc. (One Omega Dr., Box 4047, mits the reference voltage at the + in- at pin 2 falls below the reference volt- Stamford, CT 06907). put of the 741 to be altered. age, the comparator will switch off. Many different kinds of thermis- When the sensitive surface of the The trigger point, of course, can be tors are available. For best results, photoresistor is illuminated, its resis- conveniently altered simply by select a thermistor that has a room - tance is very low, typically a few hun- changing the setting of R2. temperature resistance of from 25 to dred ohms. Therefore, the voltage Incidentally, this operating mode 50 kilohms or so. I prefer to use glass - appearing at pin 2 of the 741 can ap- can be reversed simply by exchanging bead thermistors, since they are very proach the supply voltage when the the photoresistor and RI in Fig. 2. small and can be safely calibrated in photoresistor is brightly illuminated. The circuit then switches off when water. But they are more expensive The 741 will switch on as soon as the the photoresistor is illuminated and than other types of thermistors. voltage at pin 2 exceeds the reference on when the photoresistor is dark. If the thermistor you select can be voltage from R1 that is applied to pin The alerter in Fig. 2 can easily be calibrated in water, you can easily ad-

64 / MODERN ELECTRONICS / February 1985

www.americanradiohistory.com just the circuit to trigger at the freez- the supply voltage exceeds the input stance, when the reference voltage is ing point of water simply by inserting voltage by about 1 volt or more. increased above gound, the positive the thermistor in crushed ice or snow. Therefore, it's important to adjust half of the output wave narrows and You can set other calibration points the supply voltage and possibly the increases in amplitude while the neg- with the help of a thermometer. Just amplitude of the input signal if true ative half becomes broader and de- adjust the temperature of a small cup clipping of the sine wave is required. creases in amplitude. The reverse oc- of water to the desired point, insert The frequency response of the cir- curs when the reference voltage is re- the thermistor, and calibrate R2. cuit in Fig. 4 depends largely upon duced below ground. the quality of the 741. The 741 I used Potentiometer RI also permits the Sine- to Square -Wave in a breadboard version of the circuit shape of the output square wave to be Converter had a peak response of 42.5 kHz at transformed into either a positive or the -3 -dB (half -amplitude) points. negative triangle wave with a clipped The sine wave is among the most im- Other operational amplifiers or com- peak. If RI is adjusted to provide a waveforms in portant electronics. parators can provide a much wider sharp peak, the comparator becomes The comparator is well- suited for frequency response. unstable and oscillates. transforming the ubiquitous sine Interesting effects can be had by The circuit in Fig. 4 will work when wave into square and other kinds of connecting the noninverting input of powered by a single polarity supply waves. As you can see in Fig. 4, this the 741 to potentiometer RI instead (pin 4 connected to ground instead of manipulation of waveforms can be of ground. This permits the reference - V). However, the comparator will achieved with the simplest possible voltage and, consequently, the cir- then respond to only the positive side comparator circuit. This circuit can cuit's operation to be altered. For in- of the incoming signal. also be used to clip that portion of a signal that rises above or below any preset level. SOLVE FOR IMPEDANCE AND PHASE ANGLE. In operation, the sine wave (or signal) is applied to the noninverting in- YOU HAVE 20 SECONDS. put of the comparator. When the reference voltage applied to the invert- 2.2 K ing input is ground, the output of the comparator remains at ground until 10 KHZ the positive (rising) voltage of the 4 mh sine wave exceeds ground potential. The output then suddenly switches to its maximum positive value and re- TIME'S UP! mains there until the voltage of the If you were using MENTORTM you'd be on problem #2. wave falls to ground potential. The comparactor then suddenly switches Whether you use electronics in your vocation or you're just beginning to learn, MENTOR'" (for the Apple II family) is an invaluable tool. off. When the voltage falls below ground potential, the output voltage PROFESSIONALS AND HOBBYISTS: Save time in the design process. Often -used formulas are at your fingertips, suddenly switches to its maximum for quick calculation of unknowns. negative value, where it remains until STUDENTS: the waveform voltage again reaches Grasp fundamental electronic principles more easily. Understand the inter- ground potential. relationships of a circuit, by varying parameters and watching the related It should be obvious that this oper- effect. ating mode transforms a sine wave EDUCATORS: into a square wave. What is not obvi- MENTOR'" has been aiding in electronic instruction for over 4 years, in high schools, colleges, and universities, throughout the country. ous, however, is that the amplitude of the square wave at the output can System Requirements: Apple II, II +, llc, Ile, Ill be much greater than that of the sine 48K RAM, 1 disk drive =ELECTRONIC DESIGN, INC wave at the input. This occurs when 5701 Prescott Avenue Lincoln, Nebraska 68506 -5155 CIRCLE 65 ON FREE INFORMATION CARD (402) 483 -2238

February 1985 / MODERN ELECTRONICS / 65

www.americanradiohistory.com ELECTRONICS NOTEBOOIC ...

The peak detector in Fig. 5 is +v placed in operation by pressing SI to discharge Cl and reset the system. Since this removes any charge stored in Cl, the reference voltage coupled back to the inverting input at pin 2 of the 741 via R2 is 0. Any signal voltage applied to the input terminals of the circuit will immediately switch the 741 on, since the signal voltage will IN exceed the reference voltage. Capaci- OUT tor Cl will then begin charging to the supply voltage through Dl. When the charge on Cl exceeds the input voltage at pin 3, the 741 immediately switches off and CI stops Fig. 4. This circuit demonstrates how a sine wave is converted to a square wave charging. At this point, the ampli- with a comparator. tude of the charge stored in Cl equals the input voltage. If the input voltage Incidentally, while experimenting as rainfall, wind velocity, light level, rises above that stored in Cl, the with the circuit in Fig. 4, I applied a temperature, revolution rate and comparator will again switch on and square wave to the input. The output many others. If a transducer is avail- CI will again begin charging until the was a trapezoid wave with sloping able that converts an event to be mea- voltage level exceeds the reference. sides. When the amplitude of the in- sured into a proportional voltage, The comparator will then switch off. put signal was adjusted to match that then the simple comparator circuit in As you can see, the peak detector of the output, a substantial delay Fig. 5 will detect and store for several automatically tracks the input volt- could be observed in the arrival of the minutes the maximum amplitude of age and stores its peak value. At any maximum positive and negative ex- the signal from the transducer. time, a new cycle can be initiated sim- cursions of the trapezoid. The circuit in Fig. 5 is called a peak ply by pressing SI to discharge CI For instance, when the frequency detector. Digital circuits are avail- and reset the system. of the incoming wave was 10 kHz, the able that can perform the same func- Reverse -biased diode DI prevents duration of both the positive and tion, but they are far more complex CI from discharging through the negative peaks of the incoming and costly. Furthermore, they re- comparator. The circuit, however, is square waves was 50 microseconds. quire an analog -to- digital (A /D) not perfect, since Cl will not long re- The positive peak of the trapezoid conversion stage in order to measure trailed the positive leading edge of the input voltage. (Continued on page 96) 0 the square wave by 20 microseconds. Fig. S. This circuit uses a comparator as a peak- voltage detector. The negative peak of the trapezoid trailed the negative leading edge of the square wave by 32 microseconds. This delay, which also occurs when other waveforms are processed by the circuit, has several possible applications. One is the conversion of a single -phase digital clock for a logic circuit into a two -phase clock. Peak Detector Often, it's important to measure the maximum amplitude of an event such

66 / MODERN ELECTRONICS / February 1985

www.americanradiohistory.com Ullllll/ COMMUNICATIONS NIIII

Shortwave -Station News And Listening Tips

By Glenn Hauser R. Moscow World Service on 4060, can be sure you picked up a true har- site unknown; 0000, Voz de Sao Vi- monic transmission. Now to our cente, Cape Verde, resuming music roundup of other listening tips: Dx- peditions. Unless you're one of after supposedly signing off, on the fortunate few already blessed 3930; 0400, Lubumbashi, Zaire, in Listening Reports with electrically -quiet rural loca- French on 7205; among many Angol- an Australia. Longtime shortwave listeners regionals, at 0500, Benguela on tion, consider going on a DX- listen- an will remember the friendly voice of Keith ing expedition. City -dwellers will 5043.5; 0522 past 0605, a new Brazil- Glover, who once handled Radio Australia's find a great improvement in recep- ian with an all -night call -in show; ID mailbag and DX programs; recently, he's re- tion away from the multitude of ur- sounds like Radio Itapora, in Ma- turned with a stamp -collecting show, Sats. noise sources. more fun, pro- capa, on 3375 kHz. 0510 UTC on 17795, 15395, 15320 kHz. There ban It's are probably additional airings, but RA ductive, and safe for several DX lis- The 13 -MHz band. If you're buy- doesn't reveal any of them on its printed teners to go on a DX- pedition to- ing a new shortwave radio, be sure it schedule. Australian DX News reports that the gether. doesn't omit the 13600 to 13800 -kHz Antarctic service in English and French is be- It's often surprising how much dif- range to be re- allocated for interna- ing transmitted from Perth with 10 kW on 15410, Fridays only at 0300 -0500 UTC. A new ferent propagation conditions can be tional in a few years. broadcasting domestic shortwave service on the 49 -and on an expedition only a hundred But this hasn't kept a number of 90 -meter bands is due to start late this year for miles from your usual location. Aus- countries from jumping the gun to es- the Northern Territory, with 100 -kW trans- tralians have several favorite sites in tablish their own priority on certain mitters at Katherine, Tennant Creek and Alice southern Victoria and coastal frequencies. Among the countries al- Springs. An SSB feeder from Lyndhurst, Vic- toria, kHz, which often provided Ra- Albertans get away on 12290 Queensland. ready using this band are Iraq, Iran, dio Austrailia reception when no other fre- from Edmonton for improved DX Israel, USSR, North and South Ko- quencies were audible, has been demoted to listening. Floridians converge on rea, Pakistan, Turkey, China, Ice- standby status only. By a year from now all Canaveral National Seashore. An land, Sweden, Netherlands with transmitters at Lyndhurst are to be closed undeveloped beach location is cer- many more sure to follow. down -this includes not only those for Radio tainly best. Even on relatively flat Australia, but also for Melbourne domestic Harmonic DXing. Some transmit- service and VNG timesignals; another site will land, there's a certain amount of hor- ters radiate a fraction of their power replace some of these. izon blockage of low -angle (and, on exact multiples of the intended Bhutan. For those who dream of hearing the thus, very distant) signals. But at sea- frequency, giving astute monitors a almost -impossible, Radio NYAB (National side, especially at some elevation on a chance to hear some really good DX, Youth Association of Bhutan) has moved from the middle of the 4 -MHz range to 3395 or cliff, this is minimized. And varia- bluff and to observe propagation kHz, monitored in Calcutta, India by Prodyut there's a psychological boost in DX tions on bands normally lacking Banerjee of Asian DX Review, with English listening by the ocean, knowing broadcast stations. Here are a few Wed. and Fri. 1330 -1400; it's less than 100 there's nothing but water between we've monitored in the last few watts, but not completely impossible if you you and the next continent. The site months: 30830, 30690, 30660, have a darkness path, lots of patience, and superb equipment (or a ticket to Calcutta). should be as far as possible from AFRTS from U.S. sites; 30210, Canada. Every few years, a Canadian gov- power lines, of course, so be pre- BBC -Ascension; 24471, La Voz del ernment scrutinizes the CBC and proposes a pared to operate all equipment off Llano, Colombia; 23440, CBC massive budget cut; this time it was even sug- batteries. Antennas several hundred Northern Quebec Shortwave Service; gested that Radio Canada International be feet long can and should be strung 23840 and 14430, Ivory Coast; 2540, split off from the CBC. That could mean a up, but take them down when you Dominican Republic or Venezuela, drastic cut in its budget and services, possibly even its termination. Furthermore, labor con- leave unless you're positive they with baseball. Times vary widely, but tracts are up for negotiation this year, which won't pose a safety hazard to other naturally the highest frequencies are could lead to a series of strikes, as happened visitors. heard only in the daytime, the lowest before. If RCI is still on the air, and you are Here's a summary of what we heard only at night. If you divide the har- new to shortwave listening, "SWL Digest" at the most recent CANAVDX: monic frequency by exactly 2, 3, 4, has a special segment most weeks explaining the basics. Listen Sats. 2135 on 17820, 15325, (times UTC) 2145, Libya booming in etc., until you find the obvious or 15150, 11945; Suns. 2305 on 11710, 9755; on 3200 in Arabic; 2200, RRI, Ujung listed fundamental, and no corre- GMT Mons. 0306 on 9755, 5960. Most weeks, Pandang, Indonesia on 4753; 2210, sponding signal is heard there, you you can also hear our own extremely current

February 1985 / MODERN ELECTRONICS / 69

www.americanradiohistory.com COMMUNICATIONS ...

DX news report. SWLD planned to mark velopments last year on shortwave was the 0600 -0755 15105, 0800 -090017825, 1000 -1050 RCI's 40th anniversary with a special program emergence of the government station in Bata 15185, 1130- 12209510, 1245- 14207265, 1430- Feb. 23 -24. as a missionary broadcaster -probably to 1650 7200, 1700 -1855 9685, 1900 -2035 11705, Unlike the mindless entertainment most do- bring in some much -needed foreign exchange. 2100-2150 6185, 2200-0050 6065, 0100 -0150 mestic U.S. and Canadian radio delivers, CBC First on 7998 kHz, and more recently on 15105, 0200 -0250 15105 (via Ralf Munster). broadcasts "Ideas," on the following topics at 15107, various English -language gospel pro- Since DW may use the same frequencies from 9:05 p.m. local time (on MW & FM) during grams from the USA have been aired between other sites, be sure to listen for a Sri Lanka ID Feb.: 3 & 10, Saving China: Canadian Mis- 2000 and 2200 UTC, one of them, "Radio Af- at opening and closing. Radio France Interna- sionaries in the Middle Kingdom; 4 & 11, Yal- rica," operating out of the unlikely location of tional is reported to be negotiating for use of ta: History as Myth; 5 & 12, The Zero Hour: Dexter, New Mexico. the DW transmitters too. Trans World Radio 1945/1985, on shattered dreams for a peaceful Greece. Voice of Greece joins the small list also has a new relay here, high power on postwar world; 6 & 13, Eyes in the Sky; 7, of legitimate broadcasters operating just mediumwave. Characters in a Minor Key: novelists and The above 6.2 MHz, supposedly reserved for coas- non -Sudan. Radio SPLA is a new clandes- Other; 14, The Darkening Mirror: Reflections tal communications, but also used by pirates tine from Ethiopia, on 9610 kHz interfering on the Bomb & Language; 17, 18 and 19, Red and Central American clandestines. A winter with Perth at 1300 -1400 in English and Arabic. Flares: Voices from the Soviet Avant Garde: frequency for the North American service at Switzerland. Hearing SRI is easy, but have 20, The Social Construction of Female Biol- 0000 -0350 UTC is 6205 kHz. you ever caught the Red Cross Broadcasting ogy; 21, Profile of I.P. Sharp, a computer Guatemala. Voice of Guatemala dabbles in Service? It uses SRI facilities the last weekend company. Three- or four -week series start the international broadcasting; in November, Artie of each month. Try for Arabic Fri. 1700 -1720 final week of February: 24, Catholics; 25, The Bigley in Texas heard a program in English, also on 17750, English Sun. 1545 -1600 on 11870, or Cold War in Canada; 26, Feminism and Fami- with French and Spanish IDs, on 6180 kHz at Spanish GMT Mon. 0000 -0020 & 0200 -0220 ly: The Debate Among Women; 27, The Hearts 2130-2300; this could also appear on 9760. on 9635. of Men; 28, History and the New Age. Japan. After sticking to the 16 -and 19 -meter United Arab Emirates. UAE Radio, Dubai, China. Radio Beijing has inserted some new bands for many years, Radio Japan finally is well worth seeking out for news of the Mid- programs into its schedule: Mons., Economic had to drop down to 25 and 31 for the 0000- dle East, features on Arab culture and history, Horizons; Weds. biweekly, Martha in Beijing; 0100 service to eastern North America- and fortnightly on weekends, mailbags. The Fris., Cultural Interchange; Sats., Press Clip- 11710 and 9645 (with 100 and 200 kW, respec- English schedule effective thru Feb. but subject pings, and China Scrapbook. The same pro- tively). March may bring a return to higher fre- to change: 1330 -1415 on 15320, 17775, 21605; grams are broadcast six times daily -1100 on quencies. 1600 -1700 on 15320, 15300, 11955; 0330 -0400 9820, 1200 on 9820 and 6160, 0000 on 9880, New Zealand. This summer (winter to us), on 9565, 11730, 15435. These are surrounded by 11860; 0100 on 11860; 0200 on 9880; 0300 on Radio New Zealand started broadcasting in Arabic programs; tune it at 0230 for call to 11970, 11860, 9860; 0400 on 11970, 9860. shorter blocks rather than continuously for 18 prayer and recitations from the Koran. Cuba. Here's the structure of Radio Haba- hours a day: 1745 -2015, 2245 -0015 and 0345- United Kingdom. A look at some BBC na Cuba's English programs, repeating in ses- 0630 on 15485 and 17705;0930 -1115 on 15485, World Service programs on particular topics: quihour cycles: Mon. -Sat.: Today in History, 9620. There's still hope that the new govern- Financial News, Sun. -Fri. 2230 and Tue. -Sun. Newscast, Commentary on International Af- ment will agree to upgrade RNZ rather than 0445; Stock Market Report, Mon. -Fri. 1939. fairs, Spotlight on Latin America, Today in kill it. Business Matters, Thu. 2030, Fri. 0330. Brit- Sports, From the Land of Music. The remain- Saipan. KFBS, another missionary station, ish Press Review, daily 0209 and 0909; From ing three programs change from day to day: is installing three transmitters. It's not clear the Weeklies, Fri. 2315, Sat. 0730. Commen- Mon., Panorama, Latin American Songs, when all three will be in use, but current sched- tary, daily 1609, 2309. World of Stamps; Tue., Cuba and the World, ules have been arranged for each: No. 1: From Our Own Correspondent, Sat. 2209, Musical QSL, The Cuban Story; Wed., Cuban 2100 -2300 9515, 0900 -1100 11720, 1100 -1300 Sun. 0315, 0730, 1115. Letter from London, Profile, Latin American songs, Socialism: the 11880, 1300 -1600 9515. No. 2: 2100 -2400 Sun. 0750, Mon. 0445, Tue. 1115, 2100. Letter New World; Thu., PO Box 7026, Musical 9650; 0900 -1100 11710, 1100 -1400 9610, from America, Sun. 0545, 1645, 2315. Letter- QSL, Marxist Review; Fri., Cuba and the 1400 -1500 11940,1500 -1600 11820,1600 -1615 box (from listeners), Fri. 1445, Sat. 0145, World, Latin American Songs, Socialism: the 9580. No. 3: 2200 -2400 15225, 1000 -1300 2315, Mon. 0530. New World; Sat., Cuban Culture, Musical 15115,1300 -1500 15350,1500 -1545 11705. All About Britain, Fri. 1945, Sat. 0030, 0530, QSL, Eyewitness Africa. The seven programs of this is in Asian languages, not English; per 1115. People & Politics Sat. 0230, 2130. Scot- on Sundays are: Today in History, Cuban Alok Das Gupta in ADXN. land This Week, Tue. 1124, 1739, 2224. Ulster Profile, The Cuban Story, From the Land of Sri Lanka. Because of its ideal location at Newsletter, Thu. 2100, Fri. 0145, 1124. The Music, PO Box 7026, Latin American Songs, the southern tip of the middle of Asia, this Week in Wales, Thu. 1124, 1739, 2224. Net- The World of Stamps. During the winter RHC country is a favorite spot for relay stations. work UK, Mon. /Wed./ Fri. 2100, and Tue./ has been using 6090 and 6140 kHz during the The Voice of America is already here, but is Thu. /Sat./ 0215, 0745, 1330. News about Bri- evenings. building a new high -power facility on a par tain, daily 0009, 0309, 1109. Radio Earth. Via Radio Clarin, 11700 kHz with its other relays; and VOA will have more Science in Action, Fri. 1615, 2030; Discov- started a Sunday marathon broadcast at 1600- control over programming content than the ery, Wed. 0330, Thu. 1830. Nature Notebook 2300, which may replace its nightly 0300 previous agreement allowed. Deutsche Welle and The Farming World, Tue. 1830, Wed. broadcast. (West Germany) expected to have the first of 1215, Thu. 0630. New Ideas, Sat. 2230, Tue. Equatorial Guinea. One of the stranger de- its new transmitters here on the air by now: 0530, Wed. 1724, Thu. 1115.

70 / MODERN ELECTRONICS / February 1985

www.americanradiohistory.com The World Today, Mon. -Fri. 1645 & 2209, African Alternative, also audible here at effect: 1400 -1600 on 9525, 1600 -2200 on 17775 Tue.-Sat. 0315, 0545. Outlook, Mon. -Fri. times, valuable for those interested in Africa. or 17830, 2200 -2400 on 15120, 0000 -0400 on

1400, 1900, Tue. -Sat. 0100. Assignment, Listen at 0500 -0545 on 1 1860 and 6005, 0630- 11970, 0400 -0600 on 9755 or 9852.5, 0600- Wed. 2030, Thu. 0230, 1130, 1615. Omnibus, 0700 on 15400, 11860, 0730 -0800 on 15105, 0800 on 6005. KVOH will use 50 kW beamed Tue. 1615, Wed. 0030, 0630. Radio Newsreel, 11860, 9600, 1500 -1530 on 18080,1615 -1745 100° for Central America, the Caribbean, and daily 0015, 1200 (exc. Sun.), 1500. 24 Hours, on 21710, 17880, 15400. All except 12040, northwestern South America. daily 0509, 0709, 1309, 2009. 9915 and 18080 are via the Ascension relay (so Meanwhile, the nation's largest private Request shows: Anything Goes, Sat. 1215, far, all out -of -band BBC frequencies are only shortwave station, WYFR, should now have Mon. 0330, 0830. Jazz for the Asking, Sat. from Britain itself). all ten transmitters on the air from Okeecho- 2030, Sun. 0630, Fri. 1215. A Jolly Good U.S.A. Last month we brought you the ten- bee, Florida, and stay on the air 24 hours, "in Show, Sat. 0815, Tue. 1515, Thu. 2115. The tative winter schedule of KVOH, Rancho Jesus' precious name." Be on the lookout for Pleasure's Yours (classical, birthday greet- Simi, California. Never mind; it now seems more new U.S. shortwave stations, KCBI in ings), Sun. 0815, 2115, Thu. 1515. Sandi Jones construction won't be completed until sum- Dallas and NDXE in Alabama. Request Show, Sun. 1345. mer, when the following schedule can go into Good listening! RE Other music programs: John Peel (progres- sive rock), Tue. 0330, Thu. 0830, Fri. 1330. Music Now, Fri. 2115, Sat. 1400, Mon. 0230. Sarah & Company, Fri. 1709, Mon. 0730, Tue. 0030. Top Twenty, Wed. 1830, 2330, Thu. 1215. Recording of the Week, Sat. 0045, Mon. 0545, Tue. 1345, Wed. 2145. Classical r 46 CHANNEL VHF TO UHF CATV /VCR CHANNEL CONVERTER POPULAR IC CHIPS UP With Built In Amplifier and Fine Tuning Record Review, Sun. 1900, Wed. 0815. Thu. NEW, Converts cable TVAIld and Super.. L M-380N 2 welt Audio Power Amp 61.49 MAN Channels to be reMlved on your TVNCR's LM.38BN 3 Low Voltage Audio Amp 1.59 1.19 Standard 0430. Meridian (arts magazine), UHF channels. NEF5NN 019151 Phase Looked Loop 3.60 2.95 Designed to enhance VCR units and cable LM-585N Phase Locked Loop t.e9 TELEPHONE LINE ANALYZER add tans. LAI-73314 Video Amp 169 98 Sat. /Wed. 1130, Sat. /Tue./ Thu. 2330, Model 1042 /Fri./ Convenient fine lonlfg control permits adjust- MG1330 video Detector 229 184 ment without special tools on screwdrivers. Fast a. easy-to-use to Oulek line MC.1349 video If Amp zee I 55 Sun. 1709. checks. oe a power reeler.. /Tue. /Thu. 01:11 In Amplifier for UHF gain of .5 to a din. Isolates problem to telephone lire MC-1350 Video It Amp 1.75 119 Channel conversion chan on top of unit. or telephone. Teats wiring for dolt MC-1352 Video II Amp *GC 2.89 209 Monitor, Wed. 1709, Thu. 0145. Wave - Easy hookup and escellen1 performance. installation and line func- 140.1358 Audio if Amp 1.75 1.64 tions hat affect telephone ropera- 1.10.13740 R.F. Modulator 3.19 2.39 Ilori. Complete Instructions incl. OMIMede13640 OurPrlce'32.95.a. ML1459 guide, Wed. 0430, 1733, Thu. 0130. In the .e% Dual Comp. Op Amp e:pa;,: 2 or more '28.95... '16.95 ... MCI 496N Balanced MoNOemmetwor le Meantime (program previews), Thu. 2105, LM -1689 Video Modulator 2.79 \Ww,MYm.ao 7- ELEMENT SANYO UHF VARACTOR TUNERS Brand New Fri. 0150, 1115. 75 OHM UHF YAGI ANTENNAS 75 Ohm Input - 45 MHz Output Hitachi NICAD RATTERIES For Channels 14 - 83 Report on Religion, Wed. 0130, 0730, 1445, Slop wasting money on onellle hat- Model 1045 TELEPHONE rheas 1411.01 batteries can 5a PRODUCT TESTER recharged over and over again. All OPTIONAL 12 db GAIN Now! Thu. 1945. Reflections, daily 0455, 0809, Winegard Tests cordedca.Cless phone opera- units are brand new - not surplus. and automatic r: UHF Antenna Sp.city Channe! ton phone Ulalees la nMODeEL I} '16.95 all basic functions. ..acts in line 4 2239, Sun. 1739. Religious Services, Mon. Preamp w' EACH '8.95 EA. 1 hand set cords, lone of puls dial 2 for '3.139 tede Gain ratogigcimuit operation, NF 1900 8 OR MORE 2 tor '5 89 0030. Sunday Half -Hour, Sun. 2030. All units are brand new Iront Sanyo sound volume aro volee Oualiry. '39.95 e.. '7.95 EA Call fer Quantity Price '329.95.. 2fore569 Good Books, Sun. 0530, Mon. 0215, Wed. 75 OHM 1945, Book Choice, Mon. 1709, 2224, Tue. Car Stereo SIGNAL BOOSTER CABLE soil! WAHL SOLDERING IRONS Modal 5F2a05 Amp9ties FM CONNECTORS radio an 0540, Wed. 0439, 2224, Tue. 2110, Thu. 0140, MODEL 7470 signals avenge 01 16d0 (8 TemporeluraAdluaSa. times). Improves 108001ion and ex- F -59 Male connector for RG- Fri. 1739, 2224. Model SC-34 Micro Soldering Station tends range lo allow a greater 5605- 59/U cable. Comes complete Compel 509.14 7906 Ian of slasOrs and reduces ladin. 44./New Version of in with your choice (speclly) of 0, Mr micro camels Install minutes under daSn on Sports Round -Up, daily 1245 (exc. Sun.), the Jerrold 400 mfg Grounded radio antenna came Separate /"' Cl Ws' crimp-type ferrule. AB SWITCH ELIMINATOR 4p. Comes with 3/32" switch and indiomr kohl. 12 VDC. 1W for '10.50 SIGNAL COMBINER GEN. INSTRUMENT LCCSR 1745, 2245. Sports Review, Sun. 0230. Sports B tyLe tip, up more o uOPRICE .24.95 296 ea. eY chan. 3 e InrMYn 50 CHAN. CATO CONVERTER sponge a stand 2030, Tue. 0230, 1130. e SW. MOS. Satellite or ascots aii int .n0.. VHF. Mal and ].wee 0 International, Mon. VCR signai insertion into e.ISting powar pPO Cad INE a4k0 K4w WWINCLIA wo MATV/CATV Mad ends Permits 117 14,t an cnanrus tMi ee barg ea iwl tide '39.95 remote control TVs to .witch be- md tñr Saturday Special, 1515 -1600 1615 -1745 (starts company Comern di cede notes to n a ILalr and record - 7700 9böneA gennà premium ^ Id vNwire on yWequr ing/view. Multi TV set opera- Dulck Cherp^ earlier in the summer). n Ha 0Md ebii1 nt EXTENDS CORDLESS TELEPHONE tion willOUt toi use of elaborate IwTlp Conflate RANGE UP TO 3 TIMES! zra quality six on /tae cMlydl In =7.1lrninuNs on annY Set Seagoing Iron QUALITY Eendpaserbandsloy To receive the ode holuene you 9ecnarp5 0epelaly m F BBCWS frequencies: 1100 -1330 on 21710, POWER TRANSFORMERS aid. Introductory 1516016 balancing altenuators sea'subscribe 1p your 1«al Gable cwneam 3,10 2 Here's Special 24V CT, 500 mA. Inserts program m e partially as the best K '99.95 $94.00 21660, 17790, 15070, 11775, 6195, 5965. el charged Caned quality. best ea. 3 4 nerendle cant EACH R YORE $37.95 '3.19 10.402.50 ea. working phone channels 214 and 3/5 exist ge sUp le 50 or more a. 1N4001 DIODES 1330 21710, 17790, 15070. 1600-1745 '2.25 x. pros OP antenna on the -1600 Our Price sa. '14.95 IS for $1.00....100 for $5.00 charge Ka means market. Simple cordless soldering iron. inSta/atidn (Sat. and Sun. 1500 -) 15260, 9515. 1745 -2000 NI SUPER COAX SALE stand. 7545 1íp. 7546 Mounts outdoors to 6 restruclwe 15070. 2000 -2200 15260, 11750, 2200 -2300 SURPLUS Does not void '29.95.. telephone SYLVANIA warranty 11750, 7325, 6175, 5975. MODEL TWO 15260, 9915, VHF VARACTOR TUNERS None áa" Cató COMPLETE KIT 45 MHz output. Channels 2 PREMIUM QUALITY 75 OHM COAXIAL RG59 TYPE Nee Soldering Iron eclu0es antenna. CABLE /U Faslest reemerging 2300 -2430 11750, 9915, 9590, 7325, 6175, through 13 as well as the mid - nand 40' Metal Cable. 80% copper braid shield, foam insulation, less .dering iron On band channels. Hookup data adaptor and easy 10.0416,1 Same 0 6120, 5975. 0030 -0230 11750, 9915, 9590, 22 AWG center conductor. Included. :ructions Specify color - Beige or Black. verge: m WHILE THEY LAST? ON1101111 9515, 7325, 6175, 6120, 5975. 0230 -0330 By fin. 1000 fl. roll '84.95 en. '13.95 e.. '39.95... 7325, 5975. 11750, 9915, 9515, 6175, 6120, ORDER NOW TOLL 0330 -0430 6175, 6120, 5975. 0430 -0630 9510, FREE R.F. ELECTRONICS OPEN TUES FRI 800.854.4655 1086-C N STATE COLLEGE BLVD.. DEPT. R 6175, 5975. 0630 -0730 9510, 6175.0730- 0900 OUTSIDE CALIFORNIA to .6 ANAHEIM. CALIFORNIA 92806 AT 10 5 714.635.5090 ,p, CLOSED SUN MON 9510, 0900-09I5, 6195. INSIDE CALIFORNIA MOST ORDERS SHIPPED WITHIN 24 HOURS - NO MINIMUM ORDER BBCWS also has a separate program for the ALL PREPAID ORDERS 2 LBS OR LESS MUST INCLUDE 02.50 SHIPPING 8 HANDLING - SHIPPED SAME DAY RECEIVED Falkland Islands, Tue. & Fri. 2130 -2200 on CIRCLE 9 ON FREE INFORMATION CARD 15390, 12040, 11820, 9915, fascinating listening and surprisingly well -heard here. And an

February 1985 / MODERN ELECTRONICS / 71

www.americanradiohistory.com !IIiI/HA RD WARE HACKER /Ï1111111111Mr

Hardware, Software & Robotics

By Don Lancaster 1 1 LORD LORD1 LORD LORD 'LORD 'LORD 01 LORDI02 M3 I N4 M5 M6 07 08 For readers who didn't catch me last ILORD 1 month, I'll try to answer most any hardware (or related software) ques- LORDS MAY BE tions from you, as well as look at LAMPS, RELAYS, VALUES, SMALL some neat hacker -type stuff. To join STEPPERS, ETC, me in the fun, write or phone per box UP TO 500 at the end of the column. MILLIAMPERES EACH MAXIMUM. driv- POWER Show me a tough computer port SUPPLY

er circuit. UP TO 40 UDC The usual microcomputer port ULM 2813 chips, such as 6822, a 6832, or an Top Uiew typically NMOS chips with 8212, are POWER SUPPLY very low drive abilities. While fine 4401 RMOHD MICRO MUST SHARE R COMMON for just getting ones and zeros into or GROUND CONNECTION. out of a micro circuit, they simply 00000000 O loads. cannot drive higher power PARALLEL MICRO MICRO Figure 1 shows you a medium pow- OUTPUT PORT GROUND er "amplifier" for computer output Fig. I Tough octal output circuit is suited for "medium power" loads that re- using the Sprague ULN2813 ports, quire up to 0.5 ampere each. octal peripheral driver. This circuit is best suited for things that need less than 40 volts and less than half an also that a common ground must be is a good idea to always connect this ampere, and where there are no safe- shared between the loads, the power protection circuitry for most loads. ty isolation hassles noise problems. supply, the ULN2813, and the micro Obvious uses include small in- that is sourcing the ones and zeros to How can I get started in assembly candescent lamps, solenoids, air be output. It is especially important language? valves, relays, small stepper motors, to avoid ground loops when you have Check into the "top 30" programs multiplexed LED arrays, hammer high -power loads sharing the same for any major personal computer, drivers, and the like. I've even used it ground circuitry as the computer cir- and you will find that 30 out of 30 as a "student proof" driver for plain cuitry. either run directly in machine lan- old light- emitting diodes. Cost is Since the darlington pairs invert, a guage or else make extensive use of under $3. high at the input produces a low at the linked machine -language routines. The chip holds eight darlington output. In turn, this lights, powers, The marketplace has spoken -if you transistor pairs, each of which can or turns on the load. A low at the in- want to sell a decent program, it must drive up to half an ampere and block put produces a no- current high at the run in machine language. BASIC and up to 40 volts. You are not allowed to output, which unlights, depowers, or Pascal need not apply. run all eight outputs at full current at turns off the load. Thus, you get The usual way of getting a pro- the same time, but the derating what you would expect -a positive gram to run in machine language is to curves on the data sheet are very logic one turns on the load. use an assembler program. The as- generous. You can easily drive the There are also eight freewheeling sembler speaks assembly language to 2813 directly from almost any micro diodes in the package. These diodes you and machine language to the port chip. A few milliamperes at the must be used if you are powering an computer, letting you automate and input is all you need. inductive load. The common connec- simplify the creation of machine -lan- Note that a separate power supply tion to all the diodes is connected to guage routines. is recommended for the loads. Note the positive end of the load voltage. It So how do you get started? The

72 / MODERN ELECTRONICS / February 1985 www.americanradiohistory.com best way I know of involves four tools. First and foremost, you will uals for your particular disk system. steps. First, and by far most impor- need a way to unconditionally reset Same goes for printers and modems, tant, is to hand code and hand debug your machine so you can stop any of course. several hundred lines of machine lan- program at any time for any reason. Oh yes. Somewhere along the way guage code without use of any assem- (An absolute reset mod for the IIe you will need an assembler program, bler at all. Then check out a simple and IIc appears elsewhere in this although this is only a tiny part of the mini -assembler, acting as an "auto- issue.) resources you need to do assembly mated pocket card." Then tear apart Next needed is a way to mini -as- work. Apple has newly overhauled the winning programs of others as a semble, single step, and debug a their EDASM assembler so it now in- detailed study to find out how it's working program. There was a mini - cludes macros and lots of other new done. Finally, step up to a full -blown assembler in older Apples available goodies. It's available on either the assembler or macroassembler of in the monitor at $F666 and activated DOS or ProDOS toolkits. One neat your choice. Then get with the pro- by an $F666G while in the "old" Ap- thing about EDASM is that it lets you gram. ple II ROM. This has recently been do "new way" editing, using Apple - The tools and resources you need upgraded into a major and essential writer to make entry and editing far along the way will, of course, change debugging package called the BUG - simpler and far more fun. with your choice of microprocessor BYTER. This is available from Ap- Of the two dozen or so other Apple and personal computer. Let's assume ple Computer as part of DOS Toolkit assemblers, some people consider the you are a 6502 person doing Apple II #A2W0011. "best" one to be the S -C Assembler, development, and look at the tools I You will also need a disassembler while the "best buy" is Big Mac by feel are important. Naturally, if you or two. CALL A.P.P.L.E.. are into other things, you'll need A dumb disassembler is built into The final resource for assembly "alike but different somehow" tools all Apples, activated by getting into programming is you yourself with that one -on -one replace these. the monitor and typing the address, lots of hands -on programming ex- Start with a 6502 pocket card. followed by an L, such as "$0800L." perience. In theory, you can get up to These are free or cheap from Rock- For serious use, though, you will where you can just barely write sec- well, Synertek, MOS Technology, want to get an intelligent disassem- ond -rate assembly- or machine -lan- and Western Design Center. Larger bler that lets you capture the source guage programs in less than three plastic cards are available from code of any program you care to. I years of solid and dedicated effort. Micro Logic and are sometimes think that DISASM IIe by Rak -Ware Only it hasn't happened yet. Not easier to use. You will also need a is a good choice. (It is the only one I even once. programming manual for the micro personally use.) But, as someone once said, the you are using. The 6502 Program- The technical reference manuals longest journey starts with a single ming Manual, again by Rockwell, for your machine are obviously step. And the reason for doing it, of Synertek, and MOS Technology is needed. Normally, these do not come course, is for the nickels, since there absolutely essential. A 6502 Hard- with the machine but have to be sep- is no other alternative to writing win- ware Manual is also available, al- erately ordered. Apple offers a Ile ning and commercially successful though not quite as useful as the pro- Technical Reference Manual programs. gramming manual. ( #A2L2005), a IIc Technical Refer- Have at it! You will also need some books on ence Manual ( #A2L4030) and Inside machine -language and assembly-lan- Macintosh. It is unthinkable to at- Any ideas on low-cost robotics? guage programming. I'm laboring tempt any useful programming with- It ever ceases to amaze me that under the delusion that my Micro out these products. low- pressure pneumatics has never Cookbook I (SAMS #21828), Micro You will need a good set of books taken off. Yet air pressure systems in Cookbook II (SAMS #21829), and for your disk operating system. On the 3 -to -6 -psi range have enormous my brand new Assembly Cookbook the Apple, Beneath Apple DOS and advantages. (SAMS #22331) can help you Beneath Apple ProDOS by Quality First off, low- pressure air is cheap bunches here. Software are essential. Naturally, and low -tech. It gives you lots of You will need some debugging you will also want the factory man- linear force easy and simply. It can

February 1985 / MODERN ELECTRONICS / 73

www.americanradiohistory.com HARDWARE HACKER

"amplify," since most of the "mus- power vents the load to ambient cle" comes from the air source. This through a filtered vent at the rear of means you do not directly have to the valve coil. The side pipe goes to provide high -power electronic driv- the load. The front pipe goes to the ers as you do with solenoids or servo air source. You can make a simple motors. Air also goes around corners manifold for several valves by taking beautifully, particularly robotic el- a piece of thick, large- diameter tub- bows. ing and punching one pinhole in it for Most important to us, low -pres- each valve. Then push the front arm sure air has fantastic hacker poten- of each valve into the pinhole. A tial. You can literally beat one of push -on pressure seal is all you need these systems out on a brick in your at 3.5 psi. The driver shown in Fig. 1 back yard, and still come up with a works beautifully on these. promising and useful product. What do you use for actuators? You will need an air source. The Traditional miniature air cylinders larger aquarium pumps are ideal, are available from Clippard. Unfor- when combined with a small storage tunately, they are also available at vessel. The latter are easily made traditional prices. Instead, let's get from plastic toilet tank floats. You Fig. 2. Typical surplus automotive nontraditional. There's a key secret can instead use a storage tank, filled EGR three -way valve is super cheap to any useful low- power, hacker - with a tire pump, or even a scuba tank and ideal for low-pressure pneumat- based pneumatic actuator: never or a Scott airpack bottle. ics. Third port vents to the atmos- have a seal that must move! All of Hoses and connectors are no big phere at the rear. your low -power air will either be deal. Get your hoses from Hygenic wasted trying to move the seal, or else and the connectors from a larger does thirty cents sound? Thirty cents! will leak right by it. plastics supply house. They are called automotive EGR Figure 3 shows three different A regulator is also needed. I've had valves, and originally were made by ways to build actuators that do not best luck running at 3.5 psi. You can Carter Carburetor. For many years have moving seals. The rolling dia- get regulators for around six bucks now, they have been available sur- phram is interesting; suitable dia- from most of the surplus houses men- plus from Jerryco, C &H Sales, Her - phrams are available from Bello - tioned below. bach and Rademan, BNF Sales, Sur- fram. Now for the fun part. You need a plus Center, and all of your usual me- I like the bellows actuators myself. control valve. Unlike electronics, chanical surplus outfits. Your near- I actually had a bunch of these blow you cannot simply connect your air est handy -dandy junkyard is also molded long ago, to use in a pneu- supply to an actuator to move it and crammed full of them. Incredibly, matic attachment to use an office Se- then disconnect it to return. Try this, these have gone begging. lectric typewriter as a computer and the air stays stuck in the pipe and Jerryco has far and away the low- printer. It worked, more or less, but the actuator will remain extended. est valve pricing, the most outrag- never became a viable product. Poly- So, you need three -way air valves eous catalog, and the most bewilder- propylene is probably the best choice that act like electronic spdt switches. ing and mind -blowing array of other of material. Some scientific supply Powered, the air supply gets con- goodies. Where else under one roof houses sell bellows pipettes that are nected to the actuator. When the con- can you get a real joystick for a B -17 almost useful as bellows actuators. trol signal is turned off, the pressure bomber, some lumber grading cray- I've also ripped apart those "pump remaining in the actuator vents to ons, scented ballpoint pens, candle the water" toys that were available a ambient through the second arm of molds, or a dummy howitzer shell? few years back. The bellows pump in- the valve. Check them out. side these worked fine. You simply will not believe the The valve is shown in Fig. 2. You Chances are that you will prefer the price of an electronic three -way air power it with + 12 volts dc to connect "bladder" or "balloon" actuator in- valve for low pressure robotics. How the air source to the load. Removing stead, since these are the cheapest and

74 / MODERN ELECTRONICS / February 1985

www.americanradiohistory.com that goes on paper involving electronics or hardware hacking that cannot be done much faster, much more simply, and far more joyously on a Macintosh. Not that there aren't any problems, though. Their smallest type fonts are the Monaco 9 -point and their Geneva 9- point. To make these look good on the screen, they are let - (R) Rolling diaphram (B) Bellows (C) Bladder terspaced. Letterspacing means that a small lowercase i is the same width Fig. 3. Low -cost pneumatic actuators avoid the "moving- seal "problem. as a capital W. Worse yet, these fonts have only one pixel between the let- are the simplest mechanically. had two possible codings for inverse ters. The result looks OK on the By the way, if you must have a seal uppercase letters. One of these is re- screen, but for a schematic, pc lay- anywhere at all, use an O -ring. These served by the IIc as a "mouse nest" to out, engineering drawing, or logic are far and away the best route, behold icon characters. You guessed it. diagram, the printed result looks sides being reasonably cheap and Older Applewriter made the wrong both awkward and cramped. standard. choice. Fortunately, there are two utilities Let us know what you come up Anyway, the program here is a available that make custom fonts with here. We may work up an article simple patch that fixes the status line quick and easy on the MAC. One of or an information exchange service if so older DOS 3.3 Applewriter IIe will these is called the Font Mover, and it this thing really takes off the way it run just fine on a IIc. Be sure to make is provided to everyone as part of rightly deserves to. this patch on only your third or MacPAINT. The second is called the higher backup copy of AWIIe. Run Font Editor. This one is normally How can I run Applewriter Ile on an the patch as an Applesloth program, sold only to system developers as a Apple IIc? and it will do the rest. minor part of a $350 package. There is a new version of Apple - A minor IIc bug still remains with The mover lets you store fonts or writer intended specifically for the the cursor temporarily changing to a install them in your machine. The ed- IIc. It is ProDOS -based and includes flashing bell or whatever when you itor lets you change the character new features such as a scrollable park on an uppercase character. This shapes and their spacing any way you 240 -character -wide -screen (spread- is both cute and rare, so don't sweat it. like. Early versions of the font editor sheets anyone ?), settable screen mar- By another one of those most as- have very poor error trapping, so ex- gins for "what you see is what you tounding coincidences, the Hard- pect the bomb icon every now and get," display of page /line position in ware Hacker phone number is also an then, and be patient. a document, a modem link, and a few independent Applewriter help line. At any rate, I've designed a few other goodies. Price of the new Ver- I've been working with the Gila Val- fonts of my own, and "improved" a sion 2.0 is $150 from your Apple ley Apple Growers Association to few others. You can easily do the dealer. An upgrade is separately maintain this service. They have lots same, or else I'll be glad to send you available for $50 from Applewriter of free patches, as well as a mind - all of mine on disk for $19.50, sent or Upgrade; just mail them your old blowing eight- diskette -side AWIIe VISA phoned per the box. AWIIe first diskette and the cover off toolkit package. Included are a variant of Monaco 9 your manual. But neither of these are that is proportionally spaced with needed. Show me a small and attractive Mac - double -pixel spacing. I call it Thatch- The only serious problem prevent- Paint font. er 9. This is just what you need for ing your use of Applewriter IIe on a If you haven't met MacPaint or schematics and other electronic IIc is that the status line gets trashed. MacDraw yet, boy are you in for a stuff. A modified version called This happens because older Apples surprise. There is absolutely nothing Thatcher 12 has enough extra vertical

February 1985 / MODERN ELECTRONICS / 75

www.americanradiohistory.com HARDWARE HACKER ...

This AWIIe CLARIFIER Applesloth program modifies Check Validity your Applewriter IIe backup diskettes to eliminate trashing of the Iic status display line. 610 PRINT 620 PRINT "[D]BLOAD OBJ.APWRT][E,A$2300 100 REM 630 IF PEEK (14472) < > 188 THEN 880 640 IF PEEK (14709) < > 41 THEN 880 110 REM ******x*******x******** 650 IF PEEK (14753) < > 57 THEN 880 120 REM * 660 PRINT "[D]BLOAD OBJ.APWRT][F,A$2300 130 REM * "CLARIFIER FOR" * 670 IF PEEK (14815) < > 188 THEN 880 140 REM * 680 IF PEEK (15052) < > 41 THEN 880 150 REM * APPLEWRITER IIe * 690 IF PEEK (15096) < > 59 THEN 880 160 REM * 700 POKE 14815,60: POKE 14816,36: POKE 14817,207: 170 REM * VERSION 1.0 POKE 14818,16: POKE 14819,2: POKE 14820,169: 180 REM * POKE 14821,62 190 REM * 710 POKE 15052,208: POKE 15053,42 200 REM * COPYRIGHT 1984 BY * 720 POKE 15062,96 210 REM * DON LANCASTER AND * 725 IF PEEK (20365) = 176 THEN POKE 20365,182: 220 REM * SYNERGETICS, BOX * REM RECONNECT HELP SCREENS 230 REM * 1300 THATCHER AZ. * 730 POKE 15096,41: POKE 15097,127: POKE 15098,201: 240 REM * 85552. 602 -428 -4073 * POKE 15099,96: POKE 15100,176: POKE 15101,208: 250 REM * POKE 15102,201: POKE 15103,64 260 REM * ALL COMMERCIAL * 740 POKE 15104,144: POKE 15105,204: POKE 15106,41: 270 REM * RIGHTS RESERVED * POKE 15107,63: POKE 15108,176: POKE 15109,200 280 REM * 750 PRINT "[D]UNLOCK OBJ.APWRT][F" 290 REM ********x***** ** ** ***** 760 PRINT "[D]BSAVE OBJ.APWRT][F,A$2300,L$30D3" 770 PRINT "[D]LOCK OBJ.APWRT][F" 300 REM This mod changes a 780 PRINT "[D]BLOAD OBJ.APWRT][E,A$2300" 310 REM backup copy of AWIIe 790 POKE 14472,60: POKE 14473,36: POKE 14474,207: 320 REM to eliminate trashing POKE 14475,16: POKE 14476,02: POKE 14477,169: 330 REM of the IIc status line. POKE 14478,62 800 POKE 14709,208: POKE 14710,42 340 REM This lets you use a 810 POKE 14719,96 350 REM DOS 3.3 version of AWIIe 815 IF PEEK (19988) = 176 THEN POKE 19988,182: 360 REM on either a IIc or IIe. REM RECONNECT HELP SCREENS 370 REM 820 POKE 14753,41: POKE 14754,127: POKE 14755,201: POKE 14756,96: POKE 14757,176: POKE 14758,208: POKE 14759,201

380 TEXT : HOME : CLEAR 830 POKE 14760,64: POKE 14761,144: POKE 14762,204: 390 HIMEM: 8000 POKE 14763,41: POKE 14764,63: POKE 14765,176: 400 VTAB 1: HTAB 8: POKE 14766,200 A$ = "Applewriter IIe CLARifier ": 840 PRINT "[ D]UNLOCK OBJ.APWRT][E" GOSUB 910 850 PRINT "[D]BSAVE OBJ.APWRT][E,A$2300,L$2F5A"

410 PRINT : GOSUB 960 860 PRINT "[ D]LOCK OBJ.APWRT][E" 420 PRINT 870 TEXT : HOME :A$ _ "IT WORKED! ": GOSUB 910:

: : : : : END 430 FOR N = 1 TO 39: PRINT CHR$ (127);: PRINT PRINT PRINT PRINT PRINT GOSUB 950: NEXT N 880 TEXT : HOME : 440 GOSUB 960 A$ = "Will not verify as AWIIe; patch ABORTED ": 450 VTAB 5: HTAB 1: GOSUB 910: PRINT : PRINT : PRINT : A$ = "This program will patch Applewriter IIe ": PRINT : PRINT : END GOSUB 910: PRINT 890 GOTO 890 460 VTAB 6: HTAB 1: 900 TEXT : HOME : CLEAR : END A$ = "to eliminate trashing of the IIc status ": 910 REM GOSUB 910 Noisy screen machine 470 VTAB 7: HTAB 1:A$ _ "line. ": GOSUB 910 920 FOR N = 1 TO LEN (A$): PRINT MID$ (A$,N,1); 480 : GOSUB 960 490 VTAB 10: HTAB 4: 930 GOSUB 950: REM Clickety clack A$ = "Patch ONLY your THIRD BACKUP copy! ": 940 NEXT N: RETURN GOSUB 910 950 ZZ = PEEK (49200) + PEEK (49200): 500 GOSUB 960: GOSUB 960 FOR M = 1 TO 17: NEXT M: RETURN 510 VTAB 14: HTAB 4: 960 FOR N = 0 TO 700: NEXT N: RETURN A$ = "Please put your THIRD BACKUP copy ": GOSUB 910 Gotchas: 520 VTAB 15: HTAB 4: changes A$ = "of AWIIe into Drive #1. Then push ": Fixes only the status line. Rare and brief GOSUB 910 in the flashing cursor symbol will remain. 530 GOSUB 960 540 VTAB 17: HTAB 12: In the above listing, [D] stands for "control -D ". All A$ = " to CONTINUE ": GOSUB 910 other brackets are real. 550 VTAB 19: HTAB 19:A$ _ " -or -": GOSUB 910 560 VTAB 21: HTAB 13: Only the "F" version patch would normally be used by A$ = " to.ABORT ": GOSUB 910 the IIc. We have also included an "E" patch for only. 570 VTAB 23: HTAB 19: PRINT " -< > -" possible use by gonzo hackers 580 VTAB 23: HTAB 21: GET Z$ on the Gila 590 IF Z$ < > " " THEN 900 This program is avaiable ready -to -run 600 REM help line's AWIIe Toolkit package.

76 / MODERN ELECTRONICS / February 1985

www.americanradiohistory.com Manufacturer & Supplier Names and Addresses stall all of the fonts under a single name. MacPaint or MacDraw will Apple Computer Gila Valley Apple Growers Rockwell International merrily pick the font for you, instead 10260 Bandly Dr. Box 809 3310 Miraloma Ave. of the size, without knowing you Cupertino, CA 95014 Thatcher, AZ 85552 Anaheim, CA 98203 just (408) 996 -1010 (602) 428-4073 (800) 854-8099 put one over on it. If you have any favorite fonts of Applewriter Upgrade Herbach & Rademan S -C Software your own design, send them along so Box 306 401 East Erie Ave. Box 280300 others can share them. There's lots of Half Moon Bay, CA 94019 Philadephia, PA 19134 Dallas, TX 75228 room left (215) 426 -1700 (214) 324-2050 on the disk. NE Bellofram 30 Blanchard Rd. Hygenic Manufacturing Howard S. Sams Burlington, MA 01803 1245 Home Ave. 4300 West 62 St. NEED HELP? (617) 272 -2100 Akron, OH 44310 Indianapolis, IN 46206 (216) 633 -8460 (800) 428 -SAMS Phone or write your hardware hacker BNF Sales questions and comments directly to 119 Foster St. Jerryco Sprague Electric Don Lancaster Peabody, MA 01960 601 Linden Pl. 115 Northeast Cutoff (617) 531 -5774 Evanston, IL 60202 Worchester, MA 01606 SYNERGETICS (312) 475 -8440 (603) 224-1961 Box 809 Thatcher, AZ 85552 C&H Sales (602) 428 -4073 2716 East Colorado Blvd. Micro Logic Surplus Center Box 174 Pasadena, CA 91107 1000 West "O" St. (213) 681 -4925 Hackensack, NJ 07602 Lincoln, NB 68501 (201) 342-6518 (402) 435 -4366 New Television Converter Book Call A.P.P.L.E. 21246 South 68 Ave. Mos Technology Synertek Kent, WA 98032 950 Rittenhouse Rd. Box 552 VIDEO (206) 872-9004 Norristown, PA 19401 Santa Clara, CA 95052 (215) 666-7950 (408) 988 -5600 SCRAMBLING Carter Carburetor Quality Software Western Design Center TECHNIQUES 9666 Olive Rd. 6660 Reseda Blvd. 2166 East Brown Rd. St. Louis, MO 63132 Reseda, CA 91355 Mesa, AZ 85203 (314) 997 -7400 (213) 344-6599 (602) 962 -4545

Clippard Minimatic Rak -Ware 7390 Colerain Rd. 41 Ralph Rd. Cincinatti, OH 45239 West Orange, NJ 07052 CIRCUITS, THEORY, WAVEFORMS, (513) 521-4261 (201) 325-1885 Subscription TV Reference Manual This information packed book details the methods used by subscrip- spacing that it is ideal for vertical circuit, but is too tiny and awkward tion TV companies to scramble and spacing inside an integrated circuit, for most anything else. descramble video signals. Covers for the individual pin callouts. Rounding the Sinewave, Gated Pulse, SSAVI out the package are system, and the methods used by The boldface option on Mac ruins some larger numerals, some fonts for most cable companies. Includes the W and M characters. So, a ver- printed- circuit overlays, and the circuit schematics, theory, wave- sion called Thatcher 10 is available usual samples and demos, and a forms and trouble shooting hints. that is bold to start with. It appears bunch of ready -to -use 7400 series in- Only $12.95 plus $2.00 first class P & H. Information $2.00, refundable. bold as normal text, and there are no tegrated- circuit schematic icons. Foreign orders please remit in U.S. problems with certain characters be- Since these are intended as single funds only. ing blocked out. I also have a minia- sized fonts, I used the trailing num- ture 3 x 5 dot font called Thatcher 14. erals as a variation number, rather ELEPHANT This one is ideal for the little numbers than as a font size. This is allowed, ELECTRONICS (Formerly Random Accessi inside the pin circles on an integrated though not standard, and lets you in- Box 41770G, Phoenix, AZ 85080

CIRCLE 27 ON FREE INFORMATION CARD February 1985 / MODERN ELECTRONICS / 79

www.americanradiohistory.com V REWE WS /1/1/hi

The latest technical books and lit- tions. Material includes VLSI con- and tables are used throughout the erature in the electronics and com- cepts, Computer Speech Recogni- text. There are eight chapters in all, puter field. tion, Robotics, the ADA language, each devoted to a specific topic. Data Base Technology, Graphics, Though the book starts off with gen- The Handbook of Computers and Documentation, and Installation eral coverage of all types of satellite Computing. Edited by Arthur H. Management, to name a few articles. communication, both video and non - Seidman and Ivan Flores. (Van No- It's amply illustrated, too, and writ- video, it devotes some 35010 of its strand Reinhold Company Inc.; 869 ten very tightly to avoid superfluous pages to home satellite TV reception pp.; hardcover; $77.50.) material. (TVRO). Two chapters are devoted This impressive handbook consists to TVRO, one dealing with the re- of 50 original articles on recent devel- Satellite Communications by Stan ceivers required for intercepting sat- opments in the computer field. It's Prentiss. (Tab Books Inc.; soft cov- ellite video and the other dealing with directed to readers who have some er; 280 pages; $11.50) the considerations and design for background in computers rather An apt subtitle for this book might TVRO installations. than to the neophyte. The text is di- be "Everything You Always Wanted vided into six subject areas: compo- to Know About Satellite Communi- 222 BASIC Computer Programs For nents, devices, hardware systems, cations But Didn't Know What To Home, School & Office by Don Rob- languages, software systems, and Ask." Packed between its covers is a erts. (ARCsoft Publishers; soft cov- procedures, with articles written by veritable one -source encylopedia of er; 285 pages; $9.95.) industry experts. Enough basic infor- information ranging from satellites A collection of short, key -in pro- mation is provided in supporting dis- in orbit and under construction to grams for the computer owner who cussions of new developments to types of services offered to home re- has the BASIC programming lan- make this a handy reference book for ception systems to security and guage is bound to provide many some fundamentals as well as more scrambling devices. Numerous hours of entertainment and /or edu- current innovations and applica- photos, drawings, block diagrams cation. This book's 223 (one more

IRO508 Central Ave. MICROWAVE TV ANTENNA SYSTEMS 1 Westfield. N.J. 07090 (2, >854.8 Freq. 2.1 to 2.7 GHz . 34 db Gain + (ßßT 4.7u, 40V601/ RADIAL 15/1.00 COMPLETE SYSTEMS: UHF -TV PREAMP PTIOV,XOR, 3 /8- Mix.5/1.0, (As featured in Radio Electronics O.M. '...... s..... M, 200K.. 6n.00 (as Pictured) May articles, 1982) L1310 S 2,1.00 This inexpensive antenna mounted pre- .,,.o1ULN2280, .9S Commercial 40" amp can add more than 25 dB of gain to BERN TO -5 HIGH QUALITY HEAT SINKS. IC. / 1.00 your system. Lots of satisfied customers TG -I8 Io/ 1.00 Rod Style $99.95 and repeat orders for this high quality kit, MOLEX PINS- 7 PIN /SARI.- 500/6.00,1,000/.6 which includes all component parts, PC HEAT SENSITIVE SWITCHES IO/I.00 BD, Case, Power Supply and Balun $34.50 LED MOUNTING ELIPS/RI"OS 15 /1.00 Parabolic 20" rEMER DIODES- 20V IC 30/1.00 Assembled Version $57.50 106002 20/1.00 Dish Style $79.95 EMIR rs REELRLERERI m Val& E1 EecN APPLE 221 -62, 221_43, 221 -65, 221 -6., 221 -.9, Fia41Et Rats Monitor KIT-539.95 221 -79, 221 -87, 221 -96, 221 -106, 221 -105, COMPONENTS 221-106 ROTARY SWITCH( POSITION, 5A 12501 2/1.00 221 -132 2.50 Down Converters PRECISION TRIM POTS -100 RMR,500 oN ,IM,2K 221- 1401ANDUSTRY REPLACEREMTRBN, 6.90 5 00L0A,EOREGULA,200K,SOOK,I M.. R3 /1.95 REPLACEMENT R 8661 CÁ32171,28 PIN IC 0.90 7.12 VOLTAGE REGULATOR IPR1MEI.... 2/1.00 211C117281TOSHILA- MORI.. OUTPUT, 1.95 (either style) $34.95 7912 VOLTAGE REGULATOR I.RIMEI.... 2/1.00 3.573545MHz COLOR SUR8T CRYSTAL .85 TAPPED TRAN1F ORMERI7A1,7.5,9,15,18V -89.95 2732 EPROMS 6.95 Power Supplies $24.95 WALL PLUG TRANSFORMER- 24V 52911.... 04.50 SIGNALMAN MARK I MODEM1300 8ÁU01 859 0164 DYNAMIC RAMINEC 86 DATE CODE, PRIME. GORILLA H1OH RESOLUTION OREEN MONITOR 073 +) (12V to 16V, DC IDEM. FOR IBM PCS I. CLONES 11SO691.. 6.50 MID. .84 LIFETIME LIMITED WARRANTY 1.0_. CRYSTALS 1.95 HIGH QUALITY COOLING FAIMPAII01.1 119 JUMBO RED LED 'S- DIFFUSED LENS. PRIME 1111 TRANSFORMERS- 6.30 1.2AMP 1.50 PARTS & LABOR Data Info (Plans) $ 9.95 NO COSMETIC REJECTS. ALL 100815/1.00,.... FAKED CHOKE, RFC-102R -102 3/1.00 0/57.50. 22. 10 6 27ÁW0 WIRE 50./1.00 COILS FOR RADIO ELEC'S FEB 04 TV PROJECT SELTAGE_MATF SVITCXING OR FOR REOIILATOR Ell - CALL WRITE ONO S T-1,1-2, L-1112.1 L L- 21.071uH1 7,118 PROJECT FEATURES ADJUSTABLE DC /DC.

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Tarim MICRO -MART accepts Visa. MC and telephone COD's. Minimum order $10 00 ShIppirg- COD'S U.S orders, $2.00. Canada and other countries $3 50 (includes ins.). Shipping rate adjusted where applicable. NJ residents add 5% sales tax MICRO -MART 508 CENTRAL AYE., WESTFIELD, NJ 07020 (201) 854 -6008 CIRCLE 48 ON FREE INFORMATION CARD 80 CIRCLE 66ON FREE INFORM A II(1A It ARD

www.americanradiohistory.com than its title claims) BASIC pro- copy of Catalog No. 9, call: 1- 800 -543 -4330 lamps, magnifiers, flexible -shaft motors, grams are designed to do this and (1 -800- 762 -4315 in Ohio). pin vises, pliers, nippers, screwdrivers, more. The programs listed are not Precision Tools Catalog. A comprehen- torches, and more. Each item listed is ac- machine -specific, nor are they writ- sive 31 -page catalog of electronic produc- companied by a photo or drawing, com- ten in a particular BASIC language. tion assembly tools is available from the plete description, shipping weight, and Vigor You must make changes in the list- Tool Co. Catalog BK -132 lists stock number. You can obtain a free copy cleaners, dividers, drills, drill press, eye by writing to: Vigor Co., 53 W. 23 ings as required to fit your system's St., loupes, files, gauges, holders, knives, New York, NY 10010. particular needs. The programs are broken down by category, beginning with fun and games and working through a repertoire of home fi- nance, learning and "business' programs, and finishing with a nice VIEW 8 TRACES ON YOUR SINGLE series of math and random -number programs. Most of the programs OR DUAL TRACE SCOPE WITH THIS listed run less than a page in length LOW COST DEVICE!! and are, therefore, relatively easy to load from the keyboard of a com- Now you no longer have to spend thousands on an expensive multi - puter and can be stored on tape or trace oscilloscope - our single trace Hitachi scope combined with this disk for loading and running at a module will allow you to view up to 8 siss 1 -4 5 -8 1 -8 simultaneously occuring analog or future time. Not all the EN AN digital (or both) signals in their real of programs NNW Ai EWFM.A\ÉFFNt, r.0 time and amplitude relationship. The will appeal to all users of this book, MPX 101 may be used on any oscilloscope, whether single, dual or mul- but everyone who invests in the book MIN`MA X MIN MAX tiple traces. Its low cost makes it a CHANNEL8 particular favorite for designers, test- AMPLITUDE SPACING SELECT will find enough of merit and /or in- POWER ers, hobbyists and repairmen who OUTPUT want to compare and analyze dis- terest to make the book worthwhile. HI LO played signals in a timing diagram INPUT format. The controls on the front SAMPLE RATE panel of the metal case allow you to vary amplitude and spacing of the displayed signals. NEW LITERATURE MODEL MPX101 FULLY ASSEMBLED & Communications Equipment Catalog. TESTED! Hamtronic's 1985 mail -order catalog lists items for the vhf /uhf/OSCAR communications enthusiast. The 40 -page, two - 88 color catalog highlights such new prod- FULL 1 YEAR ucts as a simplex autopatch kit, a repeater REPLACE- COR with MENT courtesy beep, GaAs FET re- WARRANTY preamps, ceiver active antennas for scan- - Made In The United States - ners, and repeater PA kits. Also included SPECIFICATIONS are FM and AM receivers, FM transmit- Inputs: 8 signals plus ground via 9 150 mV /step @ 5V Input input leads terminated with alliga- Multiplex Rate: Switch selectable, 40 ters, vhf and uhf transmitting and receiv- tor clips KHz or.4 KHz ing converters, repeaters, Space Shuttle Bandwidth: ± 1dB to 5 MHz Impedance: 50 Ohms Impedance: 10.9 K Power: 105 -135 VAC @ 1 V a receivers, 800 -MHz scanner converters, Input Voltage: ± 5V peak (diode Dimensions: 6.25" x 3.25" x and other products that have been in pre- clamped to ± 5 Volt supplies) 4.75" (WxHxD) Output: Staircase waveform summed Operating Temperature: 0 -40 °C vious Hamtronics catalogs. For a free with input signals, 0 -800 mV Weight: 1 lb. 10.5 oz. full scale Warranty: one year full replacement copy, write: Hamtronics, Inc., 65 Moul Step Amplitude: Variable 0 to 150 warranty from date of purchase Rd., Hilton, NY 14468. mV/ step Lighted on /off power switch Signal Voltage: Variable 0 to Wood grain finished metal case Equipment & Parts Catalog. Catalog No. 9 from MCM Electronics contains 128 DISTRIBUTOR AND REPRESENTATIVE INQUIRIES INVITED pages with more than 4500 test equipment, computer accessories, CATV equipment, and parts listed. Among the IN MI miscellaneous items listed are telephone accessories, speakers, TV parts (flyback E. W. ENGINEERING, INC. transformers, yokes, etc.), switches, resistors, capacitors, fuses, lamps, phono VISA, MASTERCARD, AMEX TELEPHONE ORDERS ACCEPTED! cartridges and styli, and a large selection 6 Herman Drive, E. Granby, CT 06026 El 203/651 -0285 of Japanese semiconductors. For a free CIRCLE 75 ON FREE INFORMATION CARD

February 1985 / MODERN ELECTRONICS / 81

www.americanradiohistory.com Circuit Design From Scratch (from page 52)

in Fig. 8. This cross -connected your vehicle has a deadbolt -type the double -pole, double -throw (dpdt) hood lock, on the firewall inside switch has positions for both posi- engine compartment are good places. tive- voltage and ground switches. If you use a relatively secure key - switch for the RESET switch, you can it in a location that isn't too Building The Project mount obvious but where it's easy for you to Using Fig. 8, you're now ready to get at in a hurry. A slide or toggle build your alarm. Assembly is simple switch, however, must be located in a and straightforward, requiring only Fig. 9. Shown here are the connec- hidden part of your vehicle, where a standard construction techniques. tions that must be made between a thief isn't likely to find it in the 15 The project's electronics can be as- screw -type terminal strip (TS1) and seconds before the alarm sounds. sembled on a piece of perforated various points in the alarm circuit Hide all wiring inside panels, under board, using solder posts and IC and vehicle's electrical system. carpeting, etc. sockets. However, if you're am- Before mounting the electronics bitious, you can design and fabricate package in its location, cut to length your own printed- circuit board and + 12 -volt and ground connections the 10 wires (eight if you've decided use it instead. will be made via TS1. against using the flashing headlights Keep in mind that the CMOS ICs option) that connect from TS1 to the used in this project can be damaged Installing The Alarm various points in your vehicle's elec- by static electricity. So take proper Remember that this is apassive alarm trical system. Install a spade lug on precautions when handling them, and, thus, doesn't require any action one end of each wire and trim away and save installation of them in their on your part to arm it. For maximum t/ " of insulation from the other end, sockets for last. security, therefore, the box contain- twist together the fine conductors, Though IC sockets aren't normal- ing the electronics is best mounted and lightly tin them with solder. ly recommended for an automotive where it won't easily be detected, pre- Connections to be made between project (vibrations and other mech- ferably in a location that's inconven- the alarm's terminal strip screws and anical stresses cause ICs to work ient for even you to access. (You'll the various points in the vehicle's loose from their sockets), they are have to mount the box in a more ac- electrical system are detailed in Fig. here to reduce to a minimum the pos- cessible location if you've decided to 9. If you wish, you can reduce the sibility of static damage. You can mount the RESET switch on or in it.) number of wires needed by eliminat- guard against the possibility of the Way up behind the dashboard or, if ing the connections to the headlights ICs working loose by applying a small daub of silicone adhesive to the bottom of their cases just before plugging them into their sockets. Fig. 10. With this simple tester, you can safely determine which wires in a vehicle the adhesive, though, Don't overdo are connected to the positive side of the battery. or you'll get it in the socket slots or on the IC pins. VEHICLE SIDE TS1 CIRCUIT SIDE You can use either an aluminum or 1® All +12V points in circuit a plastic box to house the project. Constant +12V point or + battery terminal Machine the box and mount screw - Any ignition - switched +12V point >-- 2® --> IC1, Pins 12 and 13 type terminal strip TSI and polarity Vehicle door switch >-- 3® -4 IC1, Pins 1 and 2 selector SI (and RESET switch S2 if having re- 4® --> K1, contact A you've decided against Wire in parallel with existing headlight switch mote control of this function) on the >--- 5® -4 K1, contact B as- box. Then install the circuit board 60 K1, contact C sembly in the box and connect and Wire in parallel with existing horn switch j - Illttt ?- K1, contact D solder the free ends of the wires com- > - ing from it to the appropriate lugs on a ® -4 IC2, Pin 9 From remote mounted reset switch (see text) the terminal strip and polarity - 9® -ÿ Circuit ground switch. Do not connect the various Vehicle chassis if negative ground, io ® Circuit ground grounds on the circuit board to the battery - terminal if positive ground - - case if you're using a metal box. The

82 / MODERN ELECTRONICS / February 1985 www.americanradiohistory.com and /or mount the RESET switch on the box. The drawing shows one wire that Active connects to the car's door switch. Make sure you connect this wire to YOURç ELECTRONIC COMPONENTS CENTER the appropriate wire on the door switch. If the door switch has only TOP QUALITY, CURRENT DATE CODE PRODUCTS one wire, that's your wire. If there are two wires, however, you'll have 7400 74 ALS - ADVANCED LS Did you receive our-) Pkg'd Pkg POtkgo'd Pkg to determine which is the correct one. ACT # Oto. Price ACT x Pnce new 1985 catalog? 05500 7400 3 1.10 05ÁO, 74ALSOS 3 1.15 To do this, you'll have to make the NAME 05512 7404 5 1.85 O5A13 74ALSO4 3 1.15 35592 simple tester shown in Fig. 10. To use 7475 2 1.00 05437 74ALS20 3 1.15 ADDRESS 05640 74121 2 1.0v O5A 70 74ALS74 2 1.00' the tester, fasten the alligator clip to CITY any convenient chassis ground point STATE in 74LS 74F ZIP CODE your vehicle and, with the door 05770 74LSOO 4 1.20 ADVANCED SCHOTTKY MAIL COUPON TO: 05776 closed, pierce first one and then the 74LS02 4 1.20 05F01 74700 2 1.00 05780 74LSO4 4 1.20 05F05 74704 2 1.00 USA: P.O. Box 9100

1 Westborough, Mass. 01581 other door switch wire's insulation 05848 74LS74 3 1.00 05F07 74F08 2 1.00 L2CANADA: 5651 Ferrier SI. 05888 74LS123 2 1.30' 05717 74F74 2 1.101 with the point of the pin and observe ME Montreal. Quebec H4P IN1 whether or not the tester's lamp 74S 74HC lights. You'll HIGH SPEED CMOS ACT a 9300 TTL know you've located 05504 74504 2 1.00 16100 749C00 3 1.20 9368PC 2.65 05508 74508 2 the correct door switch wire when the 1.00 16105 74HC04 3 1.25 9374PC 2.65 05125 74S74 1 .55 16130 74HC14 1 89 9314PC 1.60 lamp is 35329 tester's with vehicle 1 off the 74S138 1.25/ 16200 1 749C244 1.50/ 9324PC 1 40 door closed. This Is a partial listingsting only. Having determined which door switch wire to use, carefully trim Mail orders shipped within 48 hours STORES OPEN AT 8:00 am away a small portion of insulation MICROPROCESSORS Pkg LINEAR ö9a Pkg."N (do not cut the wire) to expose the ACT 4 Price ACT a Price 06011 317ÚC 2 1.50 12001 6502 4.75 06017 324PC 3 1.15 conductors. Wrap the free end of the 12005 6522 6.95 06113 339PC 3 1.15 12010 6551 10.85 06114 358TC 3 1.10 door -switch wire coming from the 12014 6802 7.50 06116 555TC 3 1.00 12017 6821 alarm around the exposed conduc- 2.95 06118 556PC 2 1.10 12021 6850 3.20 tors, solder the connection, and wrap 41002 Z -80A- CPU -PS 4.25 INTERFACE 41004 Z- 80- PIO -PS 3.95 28145 SN7515OP 1 .75 with electrical tape. Reinstall the 12053 8088DC 26.80 28150 SN75154N 1 .72 12029 8224 8.59 28225 SN75477P 2 1.55 door switch. 12038 8284APC 9.89 28235 SN75492AN 2 1.00 Connect the remaining wires corn- STATIC RAMS 48049 P5101 -45L (256x4) 450 NS 4.50 CMOS ing from the alarm box in the follow- 48002 P2114 -20 (16x4) 200 NS 1.99 08340 4011BPC 4 1.00 ing sequence: ignition 48003 P2114-20L (16x4) 200 NS 2.90 08545 4066BPC 3 1.00 switch; chassis 48005 P2016-15L (2Kx8) 150 NS 5.95 08725 4538BPC 1 1.00 ground (under any screw head that 48008 P6116 -15L (2Kx8) 150 NS 7.95 08375 40168PC 3 1.00 48050 P5516 -25L (2Kx8) 250 NS 8.25 provides a positive electrical connec- Low Power REGULATORS DYNAMIC RAMS 09210 78LOSAWC 3 1.00 tion to the vehicle's chassis) for a neg- 09220 7805UC 2 1.00 48011 P4164 -15 150 NS (64Kx1) 5.65 09370 7905UC 2 1.10 48037 P4116- 15(16K01)150 NS ative- ground system, or directly to .99 09425 7915UC 2 1.10 the negative terminal of the battery in PROMS LEDS 71017 32X8- TS -16PC 16 Pin 2.79 RESET 13268 LED -209A (Red -5MM) 6 a positive -ground system; 71004 256X4-TS -16PC 16 Pin 3.69 1.19 13056 LED-220 (13/4- Red -5MM) 7 71020 512X8-TS -20PC 20 Pin 9.09 1.00 switch, if mounted outside the alarm 13271 LED -211 (13/4- Green -5MM) 5 71019 256X8- TS -20PC 20 Pin 6.69 1.00 13277 LEU-224 (14- Yellow -5MM) 5 box; horn; headlights; 1.00 and any part EPROMS of the electrical system that has + 12 48014 C2516-45 (2Kx8) 450 NS Intel Pinout 5.25 OPTO COUPLERS 48016 2732A -30 (4Kx8) 300 NS 7.50 13193 MCT2E 2 1.79 volts at all times. The connections 48018 C2764 -30 (8Kx8) 300 NS 9.95 13067 4N26 2 1.79 48021 C2532-45 (4Kx8) 450 NS T.I. Pinout 5.95 13184 4N35 1 1.00 from the relay's 48041 contacts connect in C2708-45 (1Kx8) 450 NS 7.25 13072 MOC3010 1 1.19 14 48053 C27128 -30 NS parallel directly across your vehicle's (16Kx8) 300 29.95 J \ 13202 MOC3011 1 1.29 headlights and horn switches. This is a partial listing only. Now you have a very practical de- TOLL FREE: 1 -800- 3.43 -0874 sign and should understand how to ORDERING INFORMATION MAIL ORDER. (U.S.) STORE LOCATIONS map out the general strategy to be P.O. Box 9100 133 Flanders Rd. Use only the ACT a when ordering. Some packages Westborough, Mass. 01581 Westborough. Mass. used when creating a sophisticated contain multiples other than one. Please note that Toll Free 1- 800 -343 -0874 (617) 366-9684 these multiples will not be broken. (outside Mass. only) 13107 Northup Way digital electronics project. "E Pkg'd Quantity is One (1) unless otherwise MAIL ORDER: (Canada) Bellevue, Wash. ., indicated. Toll Free 1-800-361-5884 (206) 881 -8191 J

February 1985 / MODERN ELECTRONICS / 83

www.americanradiohistory.com NEW PRODUCTS ... (from page 11)

compact Model ACT-1 Power An- antenna with a low -noise preamplifi- signals and is reputed to frequently tenna neatly solves this problem. er in its base. Although much smaller outperform much larger antennas be- Easily installed on any vertical sur- than a full -size outdoor antenna (it's cause of its active booster amplifier. face with just four woodscrews, the only 25 " tall), the ACT -1 is claimed The built -in preamp has a gain of ACT -1 provides a broadband whip to provide good coverage of distant up to 15 dB. A low -noise microwave transistor in the preamp provides a 30-to -800 -MHz bandwidth for coverage of the low -band, high -band, and uhf channels. By amplifying the weak signal from the antenna before QUALITY TRIPLE -REGULATED feeding it to the scanner, the ACT -1 A is said to solve the age -old problem of Feeder -cable losses that can seriously POWER SUPPLY AT A LOW, degrade the signal. The supplied 50- NOT A ft. cable from the ACT -1 plugs directly into the antenna and 12 -volt jacks LOW PRICE!! KIT! on the rear of most scanner receivers. If your particular receiver doesn't have a 12 -volt terminal, a plug -in adapter is available. $79. CIRCLE 96 ON FREE INFORMATION CARD

MODEL PS101 This DC triple regulated variable power supply FULLY ASSEMBLED & TESTED! has all the features you could ask for plus a full 1 year guarantee. Fully adjustable from 1'h VDC to 35 VDC! Three completely independent supplies that offer many advantages! They can be either a pos. supply or a neg. supply...they can also be stacked in series so that a 5V and two 15V sup- 88 plies can total a 35 VDC supply or any combina- S FULL 1 tion of the three...(after one of the terminals is YEAR grounded to give it a reference)...forthe first time REPLACE- you can now purchase this American made fully MENT adjustable power supply at a price that is one - 1 WARRANTY half of what you'd expect to pay! - Made In The United States - SPECIFICATIONS 3 outputs: Protection built in, current limiting, with Fixed 5 VDC ± 0.2V thermal shutdown. 2 variable $Ph V to 215 VDC Power: 108 -135 VAC. used as pos. or neg. Polarity -floating; can be Dimensions: WA" x 31/4' x 71/4' (WxHxD) Ripple less than 10mV at full load, Wood grain finished metal case. Soldering Iron Tip Cleaner Regulation <1% no load to full load, Weight: 4 lbs., 9 ozs. <0.2% 108 VAC to 135 VAC. Line Regulation Lighted on /off power switch, easy-to -read New from Davle Tech Inc. is the Current: Voltmeter and large binding posts. Fixed supply 1.0 amp max. Warranty: one year full replacement Model EL -200 soldering -iron tip Variable supplies 0.5 amp max. warranty from date of purchase. cleaner for the electronics work- DISTRIBUTOR AND REPRESENTATIVE INQUIRIES INVITED bench. The electrically operated device is claimed to clean a soldering tip MI in less than a second. Cleaning is per- I_ formed by moist sponge rollers that surround the soldering tip without E.W. ENGINEERING, INC. twisting or turning the soldering VISA, MASTERCARD, AMEX TELEPHONE ORDERS ACCEPTED! iron. The Model EL -200 is available 6 Herman Drive, E. Granby, CT 06026 203/651 -0285 in 117- and 230 -volt ac versions. CIRCLE 97 ON FREE INFORMATION CARD CIRCLE 22 ON FREE INFORMATION CARD

84 / MODERN ELECTRONICS / February 1985

www.americanradiohistory.com PRODUCT EVALUATIONS Zenith's New VHS Camcorder (from page 18)

played back monaurally. For the au- combined video camera /recorder. In of one hand. Therefore, you may dio, there is a full erase head, and re- spite of some faults, it does the job want to steady the camcorder with cording is directly controlled by mea - for which it was designed. Its easy- the other hand when shooting certain chacon with signal information on touch control buttons and clearly scenes and engaging controls. the usual top horizontal track. labeled switches are a pleasure to use, Vertical and horizontal resolution, Whenever a problem occurs, the as are its good sensitivity, zoom, and S /N, and low light level pickup are equipment stops and a LED at the af- iris controls. either average or better than average

fected location flashes at a 1 -Hz rate The REC button permits a scene to for a camcorder. Grey -scale linearity for 5 minutes and power is cut off. If be previewed before you begin re- is almost exceptional. We wish, how- the drum motor should quit during cording, and the stop /record func- ever, that colors did not contain so record /pause, the stop mode con- tion revs up the motor so that it's up much yellow on playback, that re- tinues for 1 second and power shuts to speed and permits recording to be cording could be controlled with a down, effecting the emergency instantaneous when the trigger single button, that the motor be made mode. This mode can be caused by a switch is touched. Rewind and fast - a little quieter, and that battery and no- supply -reel sensor input, no cap- forward gallop along at three times cassette operation lasted consid- stan flywheel pulses, mode control the normal /,1' -in. -per- second writing erably longer than they do. loading and unloading for more than speed, and a memory feature will lo- These slight negatives aside, we 10 seconds with no shift, or unde- cate tape positions you want the cam- give JVC and Zenith at least an A for tected drum pulses. corder to remember later on during effort and an 8 out of a possible 10 playback and stop. for execution. The first time out of User Comment This is primarily a hand -held -not the gate, the Model VM6000 repre- Like its competitors, this Zenith a shoulder- product. Its small 4 -to- sents a worthy VHS challenger to camcorder is a first -time attempt at a 5-lb. weight rests mostly on the heel 8 -mm camcorders. -Stan Prentiss

CIRCLE 99 ON FREE INFORMATION CARD

Send S1 UU postage and handling QUALITY COMPONENTS - NOT MAIL ORDER "SECONDS" for FREE COMPLETE CATALOG which includes coupon fur S1 00 OFF purchase IC- KOOLERS- from SCREW MACHINED SOCKET UiNITRACK imamate Stock No. Pins PINS, loose, packaged in bags of I WIRE TI LOW PROFILE ARIES ZERO 2 wens of neat from as In IC Pd. INSERTION Ie, poles,rq IoperNe 100. Stock No. 11310 is solder all WRAP SOCKETS d b,ner phi 22226 14 $.29 with gold collet tin shell. Stock No FORCE Just nusq lenfrOm 1- 22226 18 .29 11311 is wire wrap with gold collet SOCKETS Tin plated hear is collected,O 10p gold shell. copper alloy SOCKETS - area bottom of IC and Tin plated Won't snake Stock I -Il-a,. w 688 contact pins No phosphor bronze cam Deacnptbn 1 Sag 5 Bags 10 Bps with gas tight seat. actuated, true zero {ÿloose. 11310 Bp 01100 contact -3 wrap insertion - tin plated solder sold«bll pins s .95 9 4.45 93.95 100 Stock 100- 11311 Bee Stock tail pins - capable of being wire wrse011 w ine 11.95 10.75 930 e,,,,, No. No Pins 99 -499 500 No. No Pins 1 -24 25-99 999 plugged into dip sockets, 11301 8 S -40 S.36 5.30 11201 8 $.10 5.09 $.08 including wire wrap. WILD ROVER 3 X 4 Elastomeric Keyboards 11302 14 .59 .54 .45 11202 14 .14 .13 .12 Touch switch Operating Each keyboard nés a p.c. 11303 16 .64 .58 .48 11203 18 .16 .15 .14 Stock No. of motion without board, elastomeric pad e C005ule ae ¢ with contacts, ABS a x 11304 18 .73 .66 .55 11204 18 .18 .17 .15 1 -9 10 -49 1 a levered No. Pins 50 arm xtremely Iasi on ji 11305 20 11205 and on with low noise Normally open - bodies and double shot a a e ^ .99 .90 .75 20 .20 .18 .16 11055 24 4.98 $4.35 93.90 molded keys Max rating: a a a 11308 22 115 1 -30 1.12 1.02 .85 11206 22 .22 11058 29 5.15 4.50 4.05 rated VAC. 6 amp mallonm re- .20 .18 sistance -.615 radius by 160 thick. 12 VDC @ 20mA 11307 24 11207 11057 40 8.81 5.95 5.35 Sleek 00 rattllee 1.25 1.14 .95 24 .24 .22 .20 Contact Res: less Than 11308 28 11058 64 12.02 10.50 9.45 Stock No. 1 -9 1 O i Up 500 ohms Bounce: less 1.52 1.38 1.15 11208 28 .28 .26 .25 1 120x409 2.. 12098 51.42 51.28 than 10 in sec. 11ía2 90x4O9 1.5 11309 40 2.05 1.86 1.55 11209 40 .40 .37 .33

8 Digit LSI Counter Modules with LCD Readouts SINGLE Single Digit Displays - Common SUB CUB I and SUB ROW OPCOA Cathode CUB II are high and Associated Stock No. Description Prica Stock quality, complete LSI 51070 Complete Function 545.110 SOCKETS No Color I 100 Counter Modules with Mounting Assemblies Evaluation Kit LCD readout. Modules 12082 Red 51.12 S .99 (includes batteries 12085 Green 1.84 1.83 plug in p.c. board but does not include Strip of 25 collet sockets /pins - (Stock No. 51071). mount odd-centercomponents 12087 Yellow 1_92 1.70 SUB CUB I display counter) 12089 Orange 2.08 1.84 Complete function Mounting P.C. easily. Gold plated contacts. evaluation kit (Stock 51071 Board 7.50 only Both Right Angle Socket for Abovi- No. 51070) contains: styles break- Stock No. 1 -24 25 50 51072 SUB -CUB I display 18.00 able to any number Displays p.c. board. 4.5V battery counter module only 1024 0.,.. s 51.70 51.50 $1.30 and variable frequency 01 contact positions Stock 51073 SUB-CUB 11 display 24.00 0a c ed No. 1 100 oscillator to supply counter module only train of Count pulses. 11010 51.24 5.99 51074 Panel Bezel 1 2.00 Strip 40 Stock No. 51070 has Evaluation Kit for of pins with single LATCH, RESET and SUB -CUB II (does not beam sockets. Tin plated TEST functions (3 include SUB-CUB II contacts OPTEL LCD's with pins luttons). P.C. board -8:8.8 counter module) Steck unplugs for bread- 51075 DATA SHEET .25 Stock No. 1 -99 100 500 1000 Stock No. 47005 board work. SUB CUB II 10850 51.09 5.90 5 -82 $.72 No. Descnphon 1 10 47005 315 dig, .5" S 5.955 5.50 B-B:B.B 47006 4 dig,.5" 5.95 5.50 The Battery Just Wrap" Tool MICRO Charts - colorful eve x 47007 4 dig., 7" 11.90 11.00 11" charts eliminate the need to Stock No 47006 New banery powered tool -ram insulated stumble through manuals and wire around 025 square posts wllnoul need summaries. Fully decoded - instant for pre-cutting and pre. stripping. Complete true row to row 14 L access - totally comprehensive - gives Stock No. 47007 with 100 n. AWG wire bt and 30 pin Outs, cycle times, buy noles,elc. etc. spacing. One side Is BEBB Stock 140 Descnpnoo Price Stock No. Reference Pric 53340 BaOery toot with PI for .300 centers Flip tool lust-wrap 23010 280 CPU 3S .95 ONE TOOL DOES I andd 100 h. 30 AWG ewe 959.95 for devices 230111 80800i8085A -95 over 8 thou 4O PINS! Scotchflex4 Breadboard 13341 bit 10.35 23012 8502 tesq 5.95 600 centers. Put device Systems Basic kit 13342 1001: blue replacement wore 7.54 23013 8048 and relatives _.. 5 95 54/7400 711. Poo,. squeeze. Stock No. Price comes with 24 13343 100 it white replacement wire 7.54 23014 in tool and Sockets, 13344 100 h yellow replacement wire 23015 e. Algorthme venous Dual 7.54 23018 5.95 Hand Tool 11059 $12.95 13345 10011 red replacement wire 7.54 80/210904 40 various Plug 23017 How to otrnerelize from sample .5.95 NEW! ANTI- STATIC MODEL 10200 $14.95 Strips, wire and tools. 23018 Word..., 5' OK MACHINE AND TOOL Kit can be used with SOCKET WRAP ID any of the six boards. IC INSERTION/ THERMOPROBE: Identifies Dead Dip socket -sizea meat. panels ö;' Components - Replaces Volt Meters! Stock No. Description Price ;tz, 03500 Basic Kit $79.95 EXTRACTION KIT with numbered noiesinpin to-te i 3299 70 p^ Identify components which do not IC dead 03511 Basic board 4.5 x 5.5 19.50 Includes DIP extractors and lions. Slip onto socket before ,Sins 220,0 emit heat. Just point thermistor probe, - in.eners to acomrredate all ICs wrapping to iaenbly pes. 7300 2r w^ 03506 Intel SBC -8010 Board, 12 x 6.75 84.95 within 1 from 14 to 40 pins Tools that Also write on them for location. /16" of board -move 03507 Motorola M -6800 Board. 9.75 x 6 42.95 ,-.102 aO pm engage conductive surfaces are lunctron, e1C. ;112; over components and see 03508 S -100 Board, 10 x 5.3 36.95 IC pan number Ob on CMOS sale und mcludeground- Simplifies initial wirewra0ping, Which are 03509 Z -80 Board. 7.7 x 7 5 39.95 Stook Mn . Prisa ing lugs hncbeshoohnq and repair dead. 03510 Eurocard Board, 63 s 3.9 21.95 13309 c 641.34 $1.95 per pack 22300 521.95 We accept VISA. MC.

2F Sot TOLL800-526-5960 CN CLUDE Sit PPING CHARGES 80 OIOS100 -53.00 SINTEC CO. e8 h 3 FREE in NJ (201) 996-4093 o,',é,°SZ5O2555pö °° CIRCLE 73 ON FREI: INFORMATION CARD February 1985 / MODERN ELECTRONICS / 85

www.americanradiohistory.com Alarms (tivii page 28)

imnA! ALERT

7R7 SM7 SRTlRIfA frost TAWS iIIIiliRlal

(5)

(6)

mits it to be mounted in any orienta- tion without disrupting its sensitive motion -sensing system. This provides complete perimeter protection without the problem of false alarms caused by wind, variations in temperature, or parking conditions that aren't level. Using passive arming and instant triggering, it requires a disarming activator (supplied) to permit entry without tripping the alarm. The system has an automatic shut- (7) off and rearm feature and is expand- able to incorporate other security devices, such as pagers, system inter- rupters, etc. It can be installed in vehicles with 6- or 12 -volt, negative - or positive -ground electrical systems.

7. The Model 5980 ($99.99) from Sears, Roebuck & Co. is a passive alarm system that automatically arms itself when the ignition is turned off and the last door is closed. The alarm "chirps" briefly after door closure to signal that the system is arming. An adjustable motion detector monitors for illegal towing, jerking and jarring, as well as entry via hood, doors, and trunk. Once activated, the system's high /low siren sounds for one minute (8) before shutting down to allow the sys-

86 / MODERN ELECTRONICS / February 1985

www.americanradiohistory.com 10. Universal Security's "Silver Bul- let" alarm ($70.25) utilizes custom single -chip technology to offer one TECHNÈ of the slickest, easiest -to- install auto HIGH alarms ever. Only four wires connect I = _ _ MANUAL OFF system, all PASSVE LOW to the vehicle's electrical 9tiE 41 inside the engine compartment. So - - - - there's no need to drill holes to route wiring through the firewall. The ENTER EFE unc-o BOX alarm is armed by briefly flicking the headlights on and then off after the engine is shut off to initiate a 45 -sec- (9 ond delay before the system arms itself. A 13- second entry delay allows you to enter your vehicle and switch on the ignition to disable the alarm. Three different alarm sounds are offered by this system. AE

SECURITY SYSTEM MANUFACTURERS Auto Page, Inc. 1815 W. 205 St., Suite 101 Torrance, CA 90501

Cal Custom Hawk 23011 S. Wilmington Ave. Carson, CA 90745

California Electronics Industries 5480 Katella, #207 Los Alamitos, CA 90720

(10) Chapman Industries 2638 United Lane Elk Grove Village, IL 60007 disabling you can obtain the Model VP9001 tern to rearm itself. A starter Products operates identically, ex- Crimestopper Security switch is also included in the alarm ($36.75) that 9620 Topanga Canyon Place package for optional use. cept that it sounds a high /low siren. Chatsworth, CA 91311

8. Sun Electric markets a complete 9. The Model TL -3000 "Ungo Box" Criterion Associates 1570 Corporate Dr., Suite F vehicle security systems, in- ($369.00) from Techne Electronics is line of Costó Mesa, CA 92626 cluding the Model VP9002 ($52.60) one of several excellent alarm sys- shown here. This alarm is one of the tems available from this company. Sears, Roebuck & Co. simpler and least expensive models Using low -power CMOS gate- array- Sears Tower, Dept. 703 available. It's manually armed via an circuitry, Ungo offers either passive Chicago, IL 60684 in or manual arming and has beeping auxiliary key switch that mounts Instrument Products visual re- Sun Electric an inconspicuous location on the audio and flashing LED 1560 Trimble Rd. vehicle's exterior. Triggering is ac- minders that temporarily come on to San Jose, CA 95131 complished by current -sensing cir- inform you that the system's time - cuitry that monitors the vehicle's ex- delay arming countdown has begun. Techne Electronics and pin To disarm the system, you must dial 916 Commercial St. isting door -jamb switches Palo Alto, CA 94303 switches installed under the hood and in a four -digit numeric code known trunk lids. A mechanical police -type only to you. All doors, hood and Universal Security Instruments siren (not legal in some municipali- trunk are "bugged" with pin switch- 10324 South Dolfield Rd. Mills, MD 21117 ties) is supplied with this system. If es, and a motion -sensing system pro- Owings you prefer a legal solid -state siren, tects against jacking and towing.

February 1985 / MODERN ELECTRONICS / 87

www.americanradiohistory.com MODERN ELECTRONICS MART Classified Commercial Rates: 90C per word, 15 -word minimum ($13.50) prepaid. (Word count includes name and address.) First word only is set boldface caps at no charge. Add 20% for additional boldface words.

Mart Display Rates: 1 " x 1 col., $120; 2" x I col., $230; 3 " x 1 col., $330. Prepayment discount 5% for 6 issues; 10% for 12 issues prepaid at once. (All advertisers with PO Box addresses must supply permanent address and telephone number. Copy is subject to publisher approval.) Mailing Information: Copy must be received by the publisher by the 20th of the third month preceding the cover date. Send Advertising material with check or money order to: Modern Electronics, Classified Department, 76 North Broadway, Hicksville, NY 11801.

DEALERS wanted: Channel 2, 3, and 4 notch ORIENTAL WOMEN AND MEN seek intel- filters. Money back guarantee. Send $15.00 ligent, literate American and Canadian corres- for sample and quantity price list. Specify pondence. Asian Exchange, Honokaa, HI channel(s). LEE KURTZ, PO Box 291394, 96727. Davie, FL 33329. Cable TV converters and descramblers. Low Control your world with your computer! prices. Quantity discounts. Send $5 for infor- Build a simple interface and control up to 48 mative catalog. R & M Distributors, P.O. Box different devices easily! Complete plans, sche- 266 -M, Boston, MA 02190. (617) 871 -5838. matics and programs in BASIC, only $9.95. disk, thousand name brand B&W Electronics, 3621 Lowden, Kalamazoo, US$8.00 including IBM -PC. Details Reli- Mich. 49008. programs for Apple, ant, P.O. Box 33610, Sheungwan, Hongkong. COMMUNICATIONS plans, kits, books. - 2% ABOVE Meter transceivers, AM/FM broadcast SCANNERS, ACCESSORIES 1750 Nationwide Fre- transmitters, ham /CB amplifiers, surveillance COST! Great Newsletter! Send Stamp for Member- bugs, much more! Catalog $1.00. PAN - quency Printouts! SPOTLIGHT -VIP, Box COM, Box 130 -ME2, Paradise, CA 95969. ship Information! 3047, Greenville, NC 27836. Automotive radio replacement parts. Delco, Ford, Chrysler, Panasonic, etc. Laran Elec- Cable Converters to Scramblers. Lowest accept- tronics, 3768 Boston Rd., Bronx, NY 10469 Price. COD shippers. Dealer inquiries $1. P.G. (212) 881 -9600; NY State: 800-446 -4430; Na- ed. Quantity discounts. Catalog CIRCLE 74 ON FREE INFORMATION CARD tional: 800- 223 -8314. Video Corp., PO Box 296, Latham, NY 12110 (518) 274-6593. POLICE /fire scanners. Bearcat, Regency. AMAZING NN Discounted proced. HPR Box 19224 Denver NEW ... REPAIR ANY TV ... EASY. Any- SCIENTIFIC and ELECTRONIC CO 80219. one can do it. 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www.americanradiohistory.com WE HAVE QUALITY PARTS, DISCOUNT PRICES AND FAST SHIPPING!

TRANSFORMERS RS -232 EXTENSION MIKE 7 CONDUCTOR REVERBERATION UNIT 120 volt CONNECTOR RIBBON CABLE primaries 41) Cel l $7.50 EACH 9 LINE CONNECTED 5 CONDUCTOR IN -LINE PLUG ACCUTRONICS COIL SPRING TYPE UNITS. USED IN 5.6 VOLTS @ 750 MA $3.00 LINES 1 THROUGH 88 20. AND CHASSIS MOUNT JACK. ELECTRONIC ORGANS TO PROVIDE ACOUSTIC DELAY 6 VOLTS @ 150 MA 51.25 DB25 MALE TO FEMALE. TWIST LOCK STYLE, SAME AS SOUND EFFECTS. INPUT IMPEDANCE 8 OHMS, OUTPUT 12 VCT @ 200 MA $2.00 10 FEET SHIELDED. SWITCHCRAFT 12CL5M IMPEDANCE 2250 OHMS. 41 /f X 161/." X 1,/id EACH 18 V. @ 650 MA $3.50 $11.00 $2.50 PER SET 18 VOLTS @1 AMP $4.50 SPECTRA-STRIP RED MARKER SOUND AND VIDEO MODULATOR 24 VOLTS @ 250 MA $2.50 MULTI - METER STRIP. 28 GA STRANDED WIRE. 24 VCT @I $ 5.00 PER ROLL (100 FT.) FOR T.I. COMPUTER AMP $4.50 SWITCHES 0 - 15 V.D.C. T.I. # UM1381 -1. DESIGNED FOR USE THIS 2-1/4" 3 STATION 2K 10 TURN WITH T.I. COMPUTERS. CAN BE USED WITH TRANSFORMER SOUARE METER MULTI -TURN POT VIDEO SOURCES. BUILT-IN A/B SWITCH. NON -INTERLOCKING MEASURES WALL SPECTROL CHANNEL 3 OR 4 SELECTION SWITCH. OPERATES ON 12 VDC. HOOK UP DIAGRAM 3 - 2PDT SWITCHES 0-15 VDC. "MOO 534 -7161 INCLUDED. EACH OPERATES $4.50 EACH ALL ARE 115 VAC $5.00 EACH $10.00 EACH IN INDEPENDENTLY PLUG SUB -MINIATURE 13/4" BETWEEN ROTARY SWITCH MOUNTING CENTERS. D TYPE 48 KEY ASSEMBLY FOR 4 VDC @ 70 MA $2.00 $1.75 EACH CONNECTOR 1 POLE T.I. COMPUTER 6 VDC @ 100 MA $2.50 6 POSITION 6 VDC @ 500 MA $5.00 5 STATION NEW TEXAS INSTRUMENTS 114" DIA X 11/2" HIGH KEYBOARD. UNENCODED. 9 VAC @1 AMP $3.00 INTERLOCKING 48 758 EACH S.P S.T. MECHANICAL 15 VAC @ 300 MA $3.00 SWITCHES. TERMINATES MADE BY ALPS 10 for 16.5 VAC @10 VA $3.50 SOLDER TYPE SUB- MINIATURE $6 00 TO 15 PIN CONNECTOR. 3- 2PDT AND 17 VAC @500 MA $4.00 CONNECTORS USED FOR SOLID METAL FRAME 4 "X 97 2 - 6PDT COMPUTER HOOK UPS. PUSHBUTTON $6.50 EACH 2 FOR SWITCHES ON FULLY DB -15 PLUG $2.75 $11.00 SPRING LEVER INTERLOCKING ASSEMBLY. DB -15 SOCKET $4.00 POWER SWITCH EDGE 31" BETWEEN DB -15 HOOD $1.50 CONNECTORS 120V INDICATOR TERMINALS MOUNTING CENTERS. DB -25 PLUG $2.75 DB -25 SOCKET $3.50 TWO COLOR $2.50 EACH CODED DB -25 HOOD $1.25 TERMINALS 5 STATION ALL ARE .156" SPACING NEON INDICATOR. RATED ON A STURDY "PARALLEL" 120 V 1/3 W. MOUNTS IN ® NON -INTERLOCKING 10 PIN 5/16" HOLE...RED LENS. 23/4 "'33/4" t- PRINTER DOUBLE POLE POWER SWITCH EDGE BAKELITE PLATE ° SAME AS ABOVE, EXCEPT PUSH -ON, PUSH -OFF. 75r EACH $1.00 EACH CONNECTOR GREAT FOR SPEAKER ENCLOSURES EACH SWITCH OPERATES CONNECTOR 10 FOR $7.00 OR POWER SUPPLIES. 'I2W 10 -A 100 FOR INDEPENDENTLY SOLDER STYLE 650- -20 $2.00 EACH $65.00 36 PIN MALE 10 FOR $2.50 EACH 18/36 $1.00 EACH $9.00 USED ON SWITCHES GOLD "PARALLEL" MINI -PUSH BUTTON SOLDER EYELET $2.00 EACH GEL CELL DATA CABLES. 22/44 TIN 2 CHANNEL LIGHT ORGAN 5.50 EACH S. P.S.T. MOMENTARY BATTERY P.C. STYLE; NO MOUNTING EARS, EASILY HOOKS INTO STEREO SPEAKERS NORMALLY OPEN $1.50 EACH 10 FOR $14.00 AND ALLOWS 110 VAC LIGHTS TO DANCE I.D.C. MALE 1/4" BUSHING WITH MUSIC. TWO SEPARATE 110 VAC SAME AS ABOVE. 358 EACH 22/44 GOLD OUTPUTS FOR HIGH AND LOW FREQUENCY WILL 10 FOR $3.25 PC. STYLE $2.00 EACH AUDIO SIGNALS. USE TWO ORGANS FOR 100 FOR 10 FOR $18.00 STEREO... PRESS $30.00 FIT ON $8.50 PER UNIT SPECIFY COLOR: 28/56 GOLD 12 VDC @ 1.2 AMP HOUR STANDARD 28/56 GOLD PLATED CONTACTS RED, BLACK, WHITE, 4" X 1 13/16" X 2 COLOR LIGHT STRING AVAILABLE $1.75 EA RIBBON CABLE. .156 CONTACT SPACING. 1/8" $8.00 EACH GREEN. YELLOW. $2.50 EACH 10 FOR 522.00 $15.00 EACH 48 PAGE CATALOG FREE! FREE! FREE! LINE CORDS KEY L.E.D.'S ASSEMBLY RELAYS COMPUTER STANDARD JUMBO TWO WIRE 5 KEY SOLID STATE RELAY DIFFUSED 6' 18ga TWO WIRE 100K u o u o $1.00 GRADE linear tape RED 10 FOR $1.50 3 FOR HEINEMANN ELECTRIC 2" LONG $1.00 10 FOR EACH 4101 -5A-140 AMP GREEN $2.00 THREE WIRE -5 1 5/8" TRAVEL 75$ EACH CONTROL: 3 -32VDC CAPACITORS YELLOW 10 FOR 52.00 18 INCH 18ga THREE CONTAINS 5 SINGLE-POLE 57/8" WIRE LOAD: 140VAC 5 AMPS 2 for NORMALLY OPEN SWITCHES 2,000 mfd. 200 VDC LONG FLASHER LED $1.00 SIZE: 2 "X 1 "X W HIGH 1 1 3/4" TRAVEL 8 FOOT 18ga THREE WIRE MEASURES 3 3/4" LONG $5.00 10 FOR $45.00 3/47O1A. 5" HIGH $2.00 754 EACH 5 VOLT OPERATION RED JUMBO SIZE EACH 6 KEY 3,600 mfd. 40 VDC DUAL 100K audio taper PI $2.00 $1.00 EACH $1.25 MINIATURE 1 3/8" DIA. 3 3/4" HIGH $1.00 31/2" LONG EACH 2 1/2 TRAVEL. $1.50 EACH SOLDERING 6 VDC RELAY 6,400 mfd. 60 VDC BI POLAR LED 2 FOR 81.70 CONTAINS 6 SINGLE -POLE SUPER SMALL 1 3/8" DIA. 4 1/4" HIGH $2.50 IRON STAND SPOT RELAY; ICRYSTALS NORMALLY OPEN SWITCHES. GOLD COBALT 22,000 mfd. 40 VDC CASE STYLE HC33 /U LED HOLDERS MEASURES 4 1/4" LONG. SPRING STEEL CONTACTS. 2 " DIA "6 "HIGH $3.00 COLORBURST TWO PIECE HOLDER 2 MHZ RATED 1 AMP AT 30 VDC; 3579.545 KC FOR JUMBO LED 8 IRON HOLDER 31,000 mfd. 15 VDC DC-DC HIGHLY SENSITIVE, TTL 10 FOR 858 200 FOR ON WEIGHTED 13/4 "DIA. 4" HIGH $2.50 $3.50 EACH $1.00 EACH $10.00 BASE. CONVERTER DIRECT DRIVE POSSIBLE, CLEAR CLIPLITE OPERATES FROM 4.3 TO 72,000 mfd. 15 VDC METAL HOLDER 6 V. COIL RES. 220 OHM. 2 "DIA. " 43/B OXIDE "HIGH $3.50 MAKE LED. FANCY 1 3/16" 13/32" 7/16" 185,000 mfd. 6 VDC VARISTOR INDICATOR. CLEAR AROMAT # RSD-6V 21/2" DIA. 41/2" HIGH $1.50 G.E. I V82ZA12 4 FOR $1.00 VOLTS, $5.00 EACH $1.50 EACH 10 FOR $13.50 50 NOMINAL D.C. VOLTAGE. 5/8" DIAMETER 3 1/2" CLAMPS TO FIT CAPACITORS 504 on 2 FOR $1.50 DESIGNED TO PROVIDE A 13 VDC RELAY SPEAKER TRANSISTORS STEADY VDC @ MA s 5 240 CONTACT: S. P.N.C. 8 OHM FROM A BATTERY SUPPLY 2N706 4 FOR 81.00 10 AMP @ 120 VAC MINIATURE TOGGLE SWITCHES IMPEDANCE, OF 3.5 TO 6.25V ARE RATED S (81 125 VAC 2N2222A 3 FOR $1.00 ENERGIZE COIL TO ALL AMPS FULL RANGE PN2222 4 FOR $1.00 S.P.D.T. SPEAKER. 1/16" X 1 1/16" X OPEN CONTACT... S.P.D.T. S.P.D.T. 2 8 OZ MAGNET. 2N2904 3 FOR $1.00 HIGH 1 11/16" COIL: 13 VDC 650 OHMS (on -on) (on -on) (on- off -on) 4" 2N2905 3 FOR $1.00 17 J DIAGONAL EACH SPECIAL PRICE $1.00 EACH P.C. STYLE, SOLDER LUG MOUNTING CENTERS. 2N2907 3 FOR $1.00 $1.50 TERMINALS. SOLDER LUG NON- THREADED TERMINALS 51.00 EACH 4 PDT BUSHING. $1.00 EACH $2.50 EACH RELAY 10 FOR 59.00 754 EACH 10 FOR $9.00 10 FOR $20.00 14 style 100 FOR $80. POWER SUPPLY W/PRE -AMP pin 10 FOR $700 100 FOR $80.00 3 amp contacts THIS SUPPLY WAS USED TO POWER 24 volt d.c. or S.P.D.T. SOLID STATE AN 8 TRACK /CASSETTE UNIT. IT S.P.D.T. D.P.D.T. 120 volt a.c. coil (on -on) WILL SUPPLY APPROX. 18 VDC AND (on- off -on) (on-on) BUZZER Used Out fully tested P.C. LUGS, INCLUDES A PRE STAR #SMB -06L. SMALL -AMP TO NON -THREADED THREADED SOLDER LUG $1.70 EACH VDC. BOOST SIGNAL LEVEL. BUSHING. BUSHING. TERMINALS 6 specify coil voltage TEL COMPATIBLE. RCA PLUGS FOR LINE IN /OUT. P.C. STYLE 51.00 EACH I°" 82.00 EACH LARGE QUANTITIES AVAILABLE EACH 754 EACH X.ii to FOR $9.001 I I 10 FOR $19.00 $1.00 SOCKETS FOR RELAY 50* ..eh 8 U E $4.50 EACH 10 FOR $7.00 100 FOR $80.00 100 FOR $18000 10 FOR $9.00 TOLL FREE ORDERS ONLY QUANTITIES LIM TED I -800-826-5432 MINIMUM ORDER $10.00 va. (ORDER ONLY) nu ELECTRORICS CORR USA: S2.50 SHIPPING (IN CALIFORNIA: 1 -800- 258-6666) FOREIGN ORDERS: ALASKA. HAWAII, 905 S. VERMONT AVE. P.O. BOX 20406 LOS ANGELES, CA 90006 INCLUDE SUFFICIENT OR INFORMATION SHIPPING (213) 380.8000 6228 SEPULVEDA BLVD. VAN NUYS, CA 91411 CALIF. RES. ADD 8 1/2% r NO C.O.D.!

CIRCLE 18 ON FREE INFORMATION CARD 89

www.americanradiohistory.com Train for the Fastest Growing Job Skill in America Only NRI teaches you to service and repair all computers as you build your own 16 -bit IBM-compatible micro

New from NRI -the only home study course that As computers move into trains you as you assemble a top -brand computer! offices and homes by the millions, the demand for trained computer service technicians surges forward. The Department of Labor estimates that computer service jobs will actually double in the next ten years -a faster growth than any other occupation. Total System Training As an NRI student, you'll get After you construct this You next assemble the After you install the disk total hands -on training as you digital logic probe, you'll power supply into the drive and monitor, you'll actually build your own Sanyo install the "intelligent" main unit of the computer. make a backup copy of the MBC-550 -2 computer from the Sanyo detached keyboard, Using the digital multi- MS -DOS operating disk, with its dedicated meter, you check all explore the 8088 microchip keyboard up. Only a person who microprocessor. keyboard connections and additional circuits. knows all the underlying funda- and circuits. mentals can cope with all the significant brands of computers. And as an NRI graduate, you'll guidance and special help whenever As you build the Sanyo from possess the up-to-the- minute you may need it. the keyboard up, you'll perform combination of theory and practical demonstrations and experiments experience that will lead you to The Exciting Sanyo MBC- that will give you a total mastery of success on the job. 550-2 -Yours To Keep computer operations and servicing You learn at your own con- Critics hail the new Sanyo as techniques. You'll do programming venience, in your own home, at the "most intriguing" of all the in BASIC language. You'll prepare your own comfortable pace. With- IBM -PC compatible computers. It interfaces for peripherals such as out classroom pressures, without uses the same 8088 microprocessor printers and joysticks. Using utility rigid night -school schedules, as the IBM-PC and the MS /DOS programs, you'll check out 8088 without wasted time. Your own operating system. So, you'll be able functioning. NRI's easy step -by -step personal NRI instructor and NRI's to choose thousands of off-the -shelf instructions will guide you all the complete technical staff will software programs to run on your way right into one of today's fastest answer your questions, give you completed Sanyo. growing fields as a computer

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CIRCLE 39 ON FREE INFORMATION CARD CIRCLE 76 ON FREE INFORMATION CARD 94

www.americanradiohistory.com /1-800-344-4539AK, HI, 218-681$879 Ic O R P O R A T/ O N

NATIONAL SEMICONDUCTOR PANASONIC QUALITY Name brand products from nationally recognized manufacturers. CHEMICALS ARIES PLESSEY MOLEX E..' AAVID CHEMWIK ATLANTIC DIODES N - MACHINE DIAMOND TOOL! UNGAR GC CH VISA ARIES PLESSEY MOLEX AAVID E. F. J. SERVICE - Computerized order processing and inventory control AS INSTRUMENTS D-KI AP PRODUCTS c DIA NATIIONALNEM CONDUC ER HPANASONICA SAVINGS - Volume Discounts OEM Quantity Pricing Toll Free 800 Number cEMO ALS tNARIES GPLÉSEY MOLEX E. I DIGrKEY . I.KEY O1KR111 0101-K Y OIGI.KEY 01015KEY 0101KEY WOW NE KEY - OtGO R OM ASV - DIOI.REY - DIOINIV 0/01411Y ------ro IIS_ 1,11.I.hr I Ili,rmuu rnnL., rIGA.In.II,I I591 03423 - DIOCKEY-ONp1KEY-DIGaWEY-p101. I-D101REY-I1R Y - OI Y -01.1 ¡Gr ReY- DI0KEY1 - - *Or KEY - DICI KEY - DIOI.RIV - OIS -RSY INTEGRATED CIRCUITS I% Metal Film Resistors EMMJrs6I;los MUMllaSVrxrO DISC CAPACITORS -FAÑAEDNIC RESIN D1PPIXTATLLBIr 4000CMOS 7. 160 CAPAn.oas CAPACITORS vata vir Car. NO KIT vs2ßß-Kd NEW!KIT NEW. 1.1703917N-8 100 0. 310 DISC 216.2407 219 ONCY CAT. NO F363N .. STA7936130 RESISTOR TAWF CAPACITORS mote 64., N tame. Ix 166.1 OH -KIT 3995 Zn7a "3.37:r *5485 13. 10 424.E SOLDER TAIL 10=2 OF 10 Panasonic LS Sarin irC" DIP SOCKETS .,- Mmmture Aluminum Electrolytic Capacitors úiCr" DILI m y. r0- 1111 .44 WV CNOICEr TIN OR GOLD. R lot 50 :15B 40. 1 10 100 NPO TYPE 32 43333944 i WiLx 9N PLATL17.60.11:914 TAIL mu N rR 47 21 74 14 46 yo.EEéYC.w.a- ou 44.391. 40180 100 ;17 i OS 26 4 63 5.250.4 .16 470 40278 AM 220 3 r;0441P nñci 1. CMS C93113 18 17 CO 400 12 3201 end 010 an 11.. 17 33.1 Om 164 1314; 1. 26131. I 75 33 10 2.0 32 332 3133,' `rM.r3e78úC* .58 úPwM.: 87 .713 69 6 49 iiaaói2so: i 1432:' ;5?30'09'I 15 I.lsa:17 13 6 09 1670113 31 4020 1 70 For lame quenonns ana mrces 34 Iowa. 757 IA cont. 013940 40.4.1.01 on 46 4 20 33.00 N500 6 49 b7i 2613201.2-15 264761.126C2 261781.1.. .06 DICI KEY 500 .18 ROW MAT SOM. TAIL im :300 90 1.643203.13 1 69 564.45AC.7 40.0 wpm Nrc 1. 2547935C6 40.43 313 500 qop 34 3 30 33 00 00d 1-733..P73 1 . 2547912C6 40400 C1814 14, mme, a .15 44 4 20 40 00 4041: MO 44 SOO 40 72 PÁb A Sr 161120.615 2 52 563732.05MC2 0616 16.6o7 u 0515 97 4 70 .0 0 1633061P.24 IK AO 61 252 1 69 r 500 503 a"mBirn`erm°i 22 .+ v.a 70 6 00 64 03 mw P2028 V ustr3e0ox C9624 24 ,un sou.. odd _ tm3g5, 4.4 MF IOCN 3.75 .70 ïr HR asst em 6 91 51 0 373 'ilté LAM. 560 01 603 n u.3v 480 IN 6 91 Pi iñ mi 1_613.132 75 61.306 90 o WIRE WRAP 122 te SOO 6 91 P2°' AN71307 90 25646 DIP SOCKETS s3 7.R SOO m D IOW 1000 31 Unloamal mount, and Eseme.ds 1.26 H mów 100 58 P300 10 s1 Sn áe25 2200 100 P2039 15 4700 ié i 43 1 of AN7B1S 90 .94 H 00. 400370 I 52 40700 mpw nólr 110 93 960 LK m 407111 mm 5 01 37 57 47 1 " Mu. 0.,206 eam w 1103380 9.13 25 25 iöf 5c M339. Perl ince. 6 91 33. E wP..s' 83 15.4 31 25 =1171401. TIN 00 Pw5 Aái 12 R mñ =00'g 775 gg1=5N 06 - ® P4307 2.,14;u1 NON 60 100 233 PAN 2713 75 31 24 B MATEO 0 WRAP R 0061 1501 IN I MO a1 1000 25 76 140 1 5K -13K 1.206 1 IPA .1 1 16 2200 26 0 15 1N34 rP45 14 17 64403 76 pi 500 81 6 97 3. 7013% u..nA . gii3 31 1.6041P-15 .96 OP621. 1600 R00m 64406 33 67 500 1 03 8 93 707 97 416341P.1.8 95 77 240 220 33 pf 560 I 03 8 89 0.6 gg 10 270 3 30706 sm 94 220 47 rowse 14 1.3B 0 300 2 7X 24K 2200 . 91 8 90 BB 03 74 60 P4403 56 01 I 17 11 80 - 370 3000 II: . 67061 ;i3 2113 330 30r 10 33 10200 2 I. P4410 93 41 500 1 56 13 38 513303N 4 53 70 7 20 - 503 2 05 17 59 7 58 v 1.103606 0 70 MOWN 63 2353° 933076 4 50 ..roo MOO 50 Su. I. 001.. Gas F. 13 E 57 P60013N SO Low vlur 2133 P. 4512 3,1 01 03 B 62 50 5 10 47K PANASONIC METALLIZED POLTISTRR 2'31 g P ers 60 0919 7 70 N593351.943 6 75 CAPACITORS 01 w ono'. 61 33'3 12 E 1 36 A we oa ? 0077 0 68 50 8 27 n o KIT U NEW! 3:13 345 a.x ,50 IS 32 14 WATT NLIN RIMINON ASSORTMENT .125 28,1 p GROOM aN 53 03 13 49.10 C9140 40 ,... ÑRA 65126 6 each rt z 750 21 162076 2.34N 2 57 750 24 261306 I 1 03 m TEX ASINSTRU E PAN ea 50 2 06 EDGEBOARD CONNECTORS /50 37 f54s 100 Panasonic TSW Series 4W SID Rule. 1m 14141 of 300 PA elf IX Pi IN Large A:uminum 76 50 50 14 a I. EIecIl0lytrc Capacitors _ !. ro IN I.NO 15 .A owe I e.u, 2.0.3N 'ms"op 65150 each wrrou.e.0O t tN p 3:3 - _ lnterle0e 016.65 11: yryv' yIl 1 10 IN x5ra1aÑ1.G.R P 61. 201395P 22: s75o 509601 77 132 M7nmT e00 I 46 II 17 1M 25 ei .r . N 91 14 73 133 LM:3RR R MOO I Q 111,11 I a 19 ái 1e100 LpIIl ] um 33E 2 133 Era r 12 132 . ZDT t a.. w n R..x.. 3w r,=nYi".rr a i2 2 IaYCN 2.% M :,;+::: 0 I 29 IA ft Wan 250 40.10001m S13.00 92 e, 0.55 IL 30 111 CO LMN 75491N .1w33 2 . 51.56 9301o.3 60.100015r 616 03 470 5.8 HOD 250 1323 17300 LM7yCN 754929 1 13 441 q 10 17 EV 49033N 1.93 29' DX 01 15/505 31, u ..,proxo0. m 2.7 4 ire; 36 .1 100 A/DD/AA 0 35 4.® 3e lot, R00 IM SERIES .100 -x.300" 1z EDGEBOARD CONNECTORS 17 41 ROO 55113193 .138 3 50 IH 611.41 41. 01003 130p 14.

361 317.0353.5 66 2611800N 6 CO 1.9337 : 93 1000 I 25 3 64 67 00 57 2167130. 3 75 7,,g04.7.1 13 46 2200 14 0 13300 18 01 6131812N 10 29 072 2161030N 3 15 6. 4700 tR00 9100 'NI7 43/117N AA 560 5350 C527 420 40 40 m .76013N. 293 16 PANASONIC V- SERIES 00 470 . 32 sla.see M.1.m.ed Pam Cu.. 00M 3310 V SERIES 350 047 I: tom. 404 I 2411883N 3 75 1:37 Lar. 260 055 22 m E. : 330 mom zt 250 07 470 3S22:1 00 64 10 C5 40 6 30 51 70 SUM.. Cp.c.ty TN.an S

27 00 E. 769 DO 25 05 E. b Co.M14411 250 511 1.101 Vona. ID. Aging 63. 4116 200 nsec 16,384.1 D Ron H. SERIES .125" ..350" Lud 5Pme Prime Pare. Lew As 31.306 E EDGEBOARD CONNECTORS sw-Hwaq 30 06 AMP CHAMP 33 46 u ü 43 CONNECTORS Pen No.

47 P.1 0 001 1 Sr 7 59 57 C4 18 5 50 53 30 C3 18 3 70 35 90

500 74 P

P.1.5 lOOO2 39 57 SILICON RECTIFIERS 76 7 35 PM. 0 0027 It 97 789 57. o 0033 7 89 57 3 45 7 03 57

4m 033 Cade Sown 3.33. P4510 0.0 II 91 L P4511 0 OM OW 400 005 34 P4514 0012 403 062 Ms 004 50 7 00 N4 SERIES .156" 51 ..200" 10 ii 5.'1115' EDGEBOARD CONNECTORS II 96 :47 61 40 610 24 PC Mara 6.1.1 P.16 0010 11 101 B 75 6370 PC 6930 P451.1 0022 Bo. 51 PC d Espe MOO 903 600 Ph; DO 4 1 CO 9 03 74 Ou

OM 13 7 10 23 7440 MM 403 E 33 OOpOAV 14 124 10 71 751.90 M118 11.1yn0 004 R 500 3t G. 6 CI le 3 27 30 52 C368 507 47. P4531 OM 15 1.32 17 39 HE 50 6:0074 400 Type Connectors 23 Latch 16 I 02 12.26 89 70 - E46130 HI 91-1 C175 475 40. C2.25 6. 570 0 ON . er 31AMP SILICON RECTIFIER

P4.5 0 I 66 14 49 MS 40 15 52 /13.50 AISSO 24 P Sou., 211 1303 13520 1.1 24 P 8.A005 P45. NI Poi P4533 p 23 P4.0 O 27 30 7 70 33 23 10 00 No DNo,qr 41. Suomo 0471 B 52 3 00 25 79 187 93 NW CAPACITORS 41556 24 6 Pene/ Screm 13 77 .00 3 Amp WRY Plum 23 2 56 22 90 19, 3 33 71162 3101 3 Amo 3301,13, AssIA 30 3 711 74 no 70. 41 3 75 3339 .90 4534 46 4 21 36 763 60 61.04 3 Amp .OPIV Plasm- 33 7 97 26 5 A P4535 0 68 A MOUNTINGG aHARDWHARDWARE . AVAILABLE 05 713 333 00 $14.95 eop:c.ATOee SEPARATELY.

The Digi.Key volume discount and service charges are simple to opply. Most items sold by igi -Kay may be combined for o volume discaen . Hems that are not discountable are identified by the SERV ICE CHARGES VOLUME DISCOUNT suffix-ND following the port number. After writing your order. total all of the discountable items and apply the appropriote discount. To t s subtotal, add the non- discountoble items hen odd 0.00 .3 9.99 Add 12.00 S 0.005 99.99 NET in the ado a d Mexico when check or money order accompanies order. rithe service charge. We pay oll shipping and insurance to addresses U.S.A., Co 10.00425.00 Add 50.75 S 100.00 -5249.99 ....Less 10, WHEN ORDERING BY PHONE, CAL 1.800.344.4539 (AR, NI, mil 218.681467 ) IM men sand yew order to OIGLRIO, Higher/ 32 5eoth, Thief River Ms, MN 56701 25.00 -$49.99 Add $0.50 S 250.00.0499.99.... Less 15% 50.00 599.99 Add 50.25 5 500.00 -:999.99.... Less 20A. r Charge, VISA C.O.D. DIGI-KEY GUARANTEE: Any pans or products purchus d from Digi -Key that prove to be defective will be You moy pay by check, money order, Mast o 100.00 6 Up No Charge 51000.00 a Up Less 25% repioced or refunded if returned within 90 days from receipt with o copy of your invoic "PRICES SUBJECT TO CHANGE WITHOUT NOTICE."

CIRCLE 85 ON FREE INFORMATION CARD February 1985 / MODERN ELECTRONICS / 95

www.americanradiohistory.com STATE OF THE ART KITS (from page 66) ADVERTISERS' tain its charge if it is not of high quali- INDEX HAL 2304 MHZ AMATEUR DOWN CONVERTERS (FREQ. RANGE 19002603 MHZ) ty or if a low- impedance voltmeter is 2301 MODEL 91 KR.. 1119.95 BASIC UNIT WITH PRE-AMP LESS DIE-CAST CASE A FITTINGS 230E MODEL 42 KIT .929.96 used to monitor the level of its AMC Sales 88 BASIC UNIT WITH PRE-AMP WITH DIE-CAST CASE I FITTINGS 230E MODEL 43 KR MAN charge. The circuit will, however, AP Products Cov.IV BASIC WITH HI -GAIN PRE-AMP WITH DIE.CAST CASE I FITTINGS 83 POWER SUPPLY MAD for several minutes or Active Component Sales Corp FOR THE ABOVE COMPLETE WITH ALL PARTS LESS CASE hold a charge POWER SUPPLY CASE All Electronics Corp 89 BLACK PLASTIC CASE - UNDRILLED even much longer if a good quality, CONIFER PARACEPTOR ANTENNA $19.96 Chemtronics 94 PERFECT FOR THE 230E MOD 2 A 3 6 DB OVER ANY DISH low -loss Mylar or polystyrene capa- HAL-PA -LI 0H22 STAGE PREAMP (KIT) SUM Cleveland Institute of Electronics 31 DESIGNED FOR THE 2301 DOWN CONVERTER. MADE TO FIGGIE citor is used for Cl. It's also impor- BACK ON THE 2304 BOARD. OFFERS 22 DB MORE GAIN. HAS IM- Devtronix Organs 94 AGE REJECTION FILTER. PRE.AMP TRANBISTOREXCHANGE 96.00 tant to monitor the output voltage Digi -Key Corp 95 EXCHANGE TRANSISTOR IN 2304 WITH NEC 54535 SLOTTED ARRAY ANTENNA...... 329.95 with a high- impedance voltmeter to E.W. Engineering, Inc 81, 84 16 DB GAIN USE WITH 2304 MOD I KIT, NO CASE REQUIRED 2100 -2500 MHZ prevent Cl from being inadvertently Electronic Specialists 94 AMR COMPLETE UNIT COMPLETE SYSTEM AS SHOWN, NOT A Electronics Book Club 57 KIT. INCLUDES A PRE-ASSEMBLED PROBE discharged. DOWN CONVERTER. DISH, POWER SUPP. 79 LV, CABLES AND CONNECTORS. TESTED Elephant Electronics UNIT. OFFERS 24 DB GAIN OR GREATER. Going Further Global Specialties 9 BUY THREE OR MORE $505K... 'AMATEUR MICROWAVE RECEIVER Grantham College of Engineering 1 EPRO 2000 PROGRAMMER -- 3199.96 The comparator applications dis- EASY TO USE NO COMPUTER NEEDED. FREE STANDING EPROM Haltronix, Inc 96 AND GAME CARTRIDGE PROGRAMMER. EASY TO USE NOW cussed here are among the simplest. MAKE ARCHIVAL COPIES FOR YOUR OWN RECORDS. THE EPRO 63 2000 CAN ALSO MAKE BACK-UP COPIES OF 2732 AND 2716 Heath Co EPROMS, OR OF THEIR RESPECTIVE EGUIVILENTS. IN EPROMS Many other applications are avail- OR ROMS. SAVE ON THOSE INDUSTRIAL SERVICE CALLS. EXTRA Information Unlimited 88 BLANK CARTRIDGES ARE AVAILABLE AT THE LOW COST OF 36.50 EA OR 9600 IN LOTS OF 10 LESS EPROM. able, and you can find representative Korsmeyer Electronic Design 65 PREAMPLIFIERS HAL PA 19 .. 39.9S circuits in semiconductor applica- MCM Electronics 37

WIDE BAND - 2.200 MHI - 19 DB BUILT AND TESTED 21 HAL PA I.E ...... 112.95 tions manuals and books about lin- McGraw -Hill Book Co.

I - - AND TESTED WIDE BAND - 10 MHZ TO A GHZ 12 DB BUILT ear integrated circuits. I'll include McGraw -Hill CEC 7 SHIPPING INFORMATION: ORDERS OVER 321 WILL BE SHIPPED Micromart 80 POSTPAID EXCEPT ON ITEMS WHERE ADDITIONAL CHARGES applications ARE REQUESTED. ON ORDERS LESS THAN Sri, PLEASE INCLUDE additional comparator ADDITIONAL 32.50 FOR HANDLING AND MAILING CHARGES. NRI Schools 90, 93 MICHIGAN RESIDENTS ADD 4% SALES TAX. SEND 20 STAMP OR in a future column. SASE FOR FREE FLYER. Phillips -Tech 80 Flific:74`21112 P12112 Reader Question RF Electronics 71 I find infrared diodes work very Radio Shack 2 HALTRONIX, INC. [M* Sintec 85 P.O. BOX 1101 well for intrusion alarms, particular- 98195 SOUTHGATE, MICH. "HAL" HAROLD C. NOW LAND Tektronix Cov.I l PHONE (313) 2854792 WEIXH ly across windows, where they can be - -. ------left on continuously. I put a plastic INFORMATION CIRCLE 72 ON FREE CARD lens, used for threading needles, in front of the IR emitter. But I don't think this is a rugged enough system for outdoors use, where light fluctua- tions are greater, distances are longer, and the lens would get dirty. Therefore, I wonder if lasers would work better outdoors. If so, what direction would I take with lasers? Gary Novak /® '/1~11y11R, N Highmore, SD &u-u'"1,-:,,© In principle, both helium -neon and diode lasers might work better outdoors. But AIGaAs infrared - emitting diodes will provide a more Free Product Information reliable, less costly system. For high Readers can obtain free information on output power, drive the diodes with products advertised by the above com- hefty current pulses. For optimum panies, as well as for some editorially sensitivity, use a pin photo -diode de- mentioned products. Simply circle the tector. This detector has a linear re- appropriate number printed below an sponse over a very wide range of light advertisement onto the Modern Elec- levels and will, therefore, work out- tronics "Free Information Service" After filling doors in daylight. You'll need an in- card bound into this issue. name and address, just mail the fraredfilter if direct or reflected sun- in your postpaid card. Your request will be for- light strikes the detector. For more warded directly to the advertiser with a about infrared- emitting information mailing label prepared by our reader - diodes and photodiodes, see The service department to ensure speedy re- Forrest Mims Circuit Scrapbook sponse. (McGraw-Hill, 1983).

96 / MODERN ELECTRONICS / February 1985

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introduces the Superior Receiver Per- backed by an internal lithium IC -R71A 100KHz to 30MHz formance. Passband tuning, memory battery. superior -grade general wide dynamic range (100dB), a coverage HF receiver with deep IF notch filter, adjustable Options. FM, RC -11 wireless innovative features includ- AGC (Automatic Gain Control) remote controller, synthesized ing keyboard frequency and a noise blanker provide voice frequency readout, entry and wireless remote easy -to- adjust clear reception IC -CK70 DC adapter for 12 volt control (optional). even in the presence of strong operation, MB -12 mobile This easy-to -use and versa- interference or high noise mounting bracket, two CW fil- tile receiver is ideal for any- levels. A preamplifier allows ters, FL32 -500Hz one wanting to listen in to Keyboard Entry. ICOM improved reception of weak and FL63- 250Hz, worldwide communications. introduces a unique feature to signals. and high -grade With 32 programmable shortwave receivers...direct 455KHz memory channels, SSB/ keyboard entry for simplified 32 Tunable Memories. crystal filter, AkMI /RTTY /CW /FM (opt.), operation. Precise frequencies Thirty-two tunable memories, FL44A. dual VFO's, scanning, select- can be easily selected by push- more than any other general able AGC and noise blanker, ing the digit keys in sequence coverage receiver on the the IC- R71A's versatility is of frequency. The frequency market, offer instant recall of unmatched by any other will be automatically entered your favorite frequencies. Each commercial grade unit in its without changing the main memory stores frequency, VFO price range. tuning control. and operating mode, and is ICOM CIRCLE 178 ON READER SERVICE CARD First in Communications

ICOM America, Inc., 2380 -116th Ave NE, Bellevue, WA 98004 / 3331 Towerwood Drive, Suite 307, Dallas, TX 75234 All stated specifications are approximate and subject to change without notice or obligation. All ICOM radios significantly exceed FCC regulations limiting spurious emissions. R71A1084

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Being the first company to make solderless breadboards isn't necessarily what makes us the best. It's all the little Leads things you don't see, like our won't buckle, clips spring clip terminals, that make won't oxidize, it all adds A P " PRODUCTS r up to longer life. ACEBOARDS so Even from the out- see there big on reliability. , side there's more is more than a pres- From our larg- to an ACEBOARD sure sensitive mount. est ACEBOARD than meets the It also insulates to prevent with over 5000 tie eye. Our durable shorts and seals the bot- points, to a single tie Acetal Copolymer tom of the individual work perfectly, bring it point block, our spring clip plastic body is a spring clip cells. back to your A P PRODUCTS terminals give you nothing good insulator with excellent If solder shavings from distributor. He'll replace it, but good, solid contact on dielectric properties. resistors or corm no hassles. every connection. They accom- And special manu- (( r ! ponent leads To help you see for yourself modate a wide variety of leads facturingtechniques l- r !:_I,tl r f i drop into the what a big difference the little and have the best electrical in the insertion of the cell, they can't things make, we're offering properties, because our spring contacts into the spread into you a 10% discount on the entire clips are solid alloy, not plated plastic body insure other cells to A P PRODUCTS ACEBOARD/ nickel. We've even developed that your Breadboard short them out. Breadboard line. enough normal force to break will always remain Take a close Just fill out the coupon through any oxides which could flat. No skimping or look at our and present it to your occur on solder plated leads. planned obsolescence ACEBOARDS. A P PRODUCTS distributor. You've come to trust our test here.Again, just good A P PRODUCTS clips for the same reason. solid contact on has the biggest Since one bad connection every connection. and most corn - can ruin a whole circuit, we pay Turn our breadboard plete line of close attention to how well our body over...and you'll dis- ACEBOARD sizes. It's spring clip terminals sit within cover another key to it's also our commit- the insulator cell areas. reliability. The ment to you Spring clip edges are double -sided that if your never exposed at the adhesive ACEBOARD insertion window. foam you'll doesn't

For the name of the distributor nearest you, r call TOLL FREE (800) 321 -9668. This ME 2 (In Ohio, call collect: (216) 354- 2101). coupon is worth 10% off the purchase price of any size ACEBOARD or Breadboard product. Offer expires 3/31/85.

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