(15 48783 BLzI- Llt l' 1'- Tu i3IlikJ i JULY 199^c Ui1ILScR; Combined with Fiectronics BU LLD 't 11-L=L1=11 1 ; LII LtiL. 1,1z81 -11a R Use -vour poi table CD player in wouv car with our híoh-quality, ealby-to-build tra .11m filer 1:11.-111;_1111_ Add a frequency counter and capacitance met3r to youi PC CLzlt nafrLlil ER Our r- ranking amp e s i im eilor will make elite VsL! get .;tranded - onüe . .by a lix eul il . bttet! - - .. _ z ' ' Cll1-ULÍ '__.41ü 1 'OQK_ ... , h0 kIN./ to use. I «. ititie:devrc.Ces t yout cie9ins . C92' 1.9111.1 Ct ' U lt ó l' 1.1OTEl-1l! k VYhurt t_ie-\rtiorld hdmínkr+rative Keep your Senshivextzta _- Ra dlo Czzfefencce t11ec:[1s to .you out of rather l'e©pie'o hand`! 303032DRK64501109_ 07 60 -UL 93 I A LLOYD DARKNELL RE IJ 52.95'U S. 1 GEMSBACR 6450 MYRTLEWOOD DR CAN T iCAtin. $3.75 CUFERTINO, CA 95014 ' fI 11 ol 04128:8713 o The Fluke 79: :Vlore Of A Good Thing JP. T.0kV4¡--á,:1.~.1,.hrL61-h'-en.,.rn More high-performance features. t More advanced measurement capa- - - -- 40.2 79 SERIES 11 MULTIMETER . bilities. More of the vital information FLUKE, , Lo -Ohms range: Our proprietary Lo -Ohms you need to troubleshoot even the function lets you measure resistance as low as toughest problems - with both ana- Qfllll' 11 1© nNF 0.01 ohms. High noise rejection and a test lead log and digital displays. 1' mVAC Zero Calibration function make the Fluke 79 ideal for detecting small resistance changes. a mV DC Meet the latest, greatest member j=r -+ '~/I'~'I'' 'awa Mk f1Hz 40 of our best selling 70 Series II family 0 1 2 3 SMOOTHING - the new Fluke 79 digital multimeter. ÍIIIIIItl11U11111111111111111111111111111111111111111111111111 nV Smoothing'": Our exclusive new Smoothing It picks up where the original fam- mode gives you a stable digital readout for ily left off. In fact, it's a quantum leap -= unstable signals - by displaying the running average of eight readings. No more jitter or forward in performance, value and I - "digit rattle" due to noisy signals. affordability. It's got the features you'd expect Get a good thing going: To put from Fluke. Including high resolution. more meter to work for you - at a Fast autoranging. Patented, automatic price that works for you, too - head Touch Hold'. A quick continuity for you nearest Fluke distributor. For beeper. Diode test. Automatic self - the name of your nearest distributor, test. Battery -conserving sleep mode. or for more product information, call And it's just as rugged and reliable as 1 -800 -87 -FLUKE. the rest of the 70 Series II family. with hand. Easy to operate, too - one The Fluke 79 comes with a yellow holster and patented And thanks to the Fluke 79's Flex -Stands - easy to proprietary new integrated circuit hang from a door or pipe, I'; technology, that's only the beginning. clip onto a belt or tool kit, or stand at virtually When it comes to zeroing in on tough nF. any viewing angle. 1`7= electrical problems, the Fluke 79 There's even storage ,' . + leaves the competition behind: space for test leads. PRESS 40x1 RANGE® Hz Fluke 79 Series II AUTORANGE, 4011 5185' Frequency: The Fluke 79's built-in frequency ©(TOUCH HOLD: -1(- era soon Count Digital Display (9999 in Hz. Capacitance. counter lets you measure from below 1 Hz to and Lo -Ohms( over 20 kHz. And while you view frequency on 63 -segment Analog Bar Graph the digital display, the analog bar graph shows V r) 0.3% Basic DC Voltage Accuracy you AC voltage. So you can see if potentially 10A-1 -pi Automatic Touch Hold hazardous voltage is present. Diode Test, Audible Continuity Beeper Autoranging, Manual Ranging 111111111 Holster with Flee -Stand WI- kHz r- Frequency Counter to over 20 1000V Fast 63 -segment analog bar graph: The Fluke zse - Capacitance. 10 pF to 9999 40-1 750V of 79's bargraph moves as fast as the eye can see, -I- - CCM _ Lo -Ohms Range with Zero Calibration updating at a rate of 40 times per second to Smoothing simulate the functionality of an analog needle. You get the high speed and high resolution you FUSED 700 Houts Battery Lite (alkaline) need to detect peaking, nulling and trending. 1 3 -Year Warranty ' Suggested U S list price Capacitance: No need to carry a separate FLUKE AND I'II I LI PS Actual Size dedicated capacitance tester; the Fluke 79 TII E T&Nt ALLIANCE measures capacitance from 10 pF to 9999 NF. John Fluke Mfg. Co . Inc P.0 Boo 9090. M/S 250E Everett. WA 98206. f Copyright 1991 Prices and specifications subject to change without notice. Ad no. 00172 FLUKE® Kl CIRCLE 121 ON FREE INFORMATION CARD July 1992 Electronlc5 Vol. 63 No. 7 P-R.. ...S. , BUILD THIS \ RAM.Y.vI. a 33 FM STEREO BROADCASTER PC Transmit line up 60 feet with this -to - r. -level audio distances of to easy PASSWORD build device. PROTECTION Luther M. Stroud, CET, N5TVY 57 CAR BATTERY TESTER 1.11.7"7.,4"-'21-"' This high-tech tester will let you know the conditon of your car's battery. Thomas R. Fox COMPUTERS PAGE 51 41 PC -BASED TEST BENCH Build the T1001 and get a frequency counter, an event/period meter, _ and a capacitance meter. ::.._... Steve Wolfe 51 PC PASSWORD PROTECTION Add password boot protection to your PC. Mark Hatten CAR R BATTERY TESTER TECHNOLOGY 38 WARC '92: RF SPECTRUM PREPPED FOR NEXT CENTURY A look at the 1992 World Administrative Radio Conference. Stanley Leinwoll PAGE 57 63 PHOTOSENSITIVE DEVICES Put photoconductive cells, photodiodes, and phototransistors to use in your projects. Ray M. Marston I AND MORE . 102 Advertising and Sales DEPARTMENTS Offices 102 Advertising Index 8 VIDEO NEWS 82 AUDIO UPDATE What's new in this fast - The kit era passes. 10 Ask R -E changing field. Larry Klein David Lachenbruch 93 Buyer's Market 88 DRAWING BOARD 4 Editorial Finishing the scope. 20 EQUIPMENT REPORT 12 Letters Paragon LA16PC Robert Grossblatt 90 COMPUTER 30 New Lit 75 HARDWARE HACKER CONNECTIONS 22 New Products Dye -based solar energy. The virtual PC. Don Lancaster Jeff Holtzman 6 What's News ON THE COVER , ElectrofliCS NOW Hugo Gernsback (1884-1967) founder There's no doubt that we've all be- come spoiled when it comes to mu- Larry Steckler, EHF, CET, sic-we're used to having music editor -in -chief and publisher CAR BATTERY UP TO SNUFF? lR'Realm where ever we go. But what happens EDITORIAL DEPARTMENT if you feel like listening to a in ielcrrnnlcs CD Brian C. Fenton, editor »AD :OE o tu e,;Nl-R yourAM/FM/cassette-equipped Marc Spiwak, associate editor u ,w ro-u co r.,r "rná n.,.are car? Or when you're mowing the Neil Sclater, associate editor ..,,. Teri Scaduto, assistant editor Bf '1.1 1L' LIB1ir711 lawn but your personal portable Add ...,..,r, cm,m M and K. Holtzman n Jeffrey *prono mr b dodo K can't pick up favorite radio sta- your computer. editor o,m..,«CAN BA1TEx1 IESTEjI tion? That's when our FM Stereo Robert Grossblatt, circuits editor m,.1 ;.«.e.r Broadcaster comes in handy. The Larry Klein, audio editor q ...... n... I ?` versatile transmitter can take music David Lachenbruch from any line -level audio source and contributing editor Don Lancaster broadcast it anywhere within a 50 contributing editor PC PQSSWOxO PBB1E6110N yew foot range. You can send audio from Kathy Terenzi, editorial assistant a~ OwOb11,i1 ,., ,. a portable CD player to your car ster- ART DEPARTMENT. : .... T.,..r.... «.v..« eo, or from your home stereo to your Andre Duzant, art director IIIÍ u . .... Walkman. Take a look at the project Injae Lee, illustrator on page 33, and see how many other Russell C. Truelson, illustrator uses you can think of! PRODUCTION DEPARTMENT Ruby M. Yee, production director Karen S. Brown a dvertising,production Marcella Amoroso COMING NEXT MONTH production assistant Lisa Rachowitz editorial production THE AUGUST ISSUE CIRCULATION DEPARTMENT Jacqueline P. Cheeseboro GOES ON SALE circulation director Wendy Alanko JULY 7. circulation analyst Theresa Lombardo circulation assistant Michele Torrillo, - BUILD AN ATV TRANSMITTER reprint bookstore Complete construction details for an amateur television trasmitter. Typography by Mates Graphics, Coverphoto by Diversified Photo BUILD A TELEPHONE VOICE SCRAMBLER Services Keep your phone conversations private! " Electronics Now is indexed in Applied Science 8 Technology Index NOTWORKING TO NETWORKING and Readers Guide to Periodical Liter- An introduction to the hardware basics and benefits of LAN's. ature. Microfilm & Microfiche editions are - available. Contact circulation depart- . PC -BASED TEST BENCH ment for details. Build an A/D converter that can be used as a low -frequency oscilloscope. _ Advertising Sales Offices listed page 102. As a service to readers, ELECTRONICS NON publishes available plans or information relating to newsworthy products, on techniques and scientific and technological developments. Because of possible variances in the quality and condition of Electronics Now Executive and materials and workmanship used by readers,ELECTRONICS NOW disclaims any responsibility for the safe and proper functioning of reader -built projects based upon or from plans or Information published in this magazine. Administrative Offices 1.516-293-3000. Since some of the equipment and circuitry described in ELECTRONICS NOWmay relate to or be covered by U.S. patents, ELECTRONICS NOW disclaims any liability for the Infringement of such patents by the making, using, or selling of any such Subscriber Customer Service: equipment or circuitry, and suggests that anyone Interested In such projects consult a patent attorney.