BAND RECEIVER - Listen -In to Dramatic Radio Communications from Pilots, Ground Controllers, and More

(,jg 48784 SPOTLIGHT ON HOME THEATE JANUARY 1993 ,

BUILD AN AVIATION -BAND RECEIVER - Listen -in to dramatic radio communications from pilots, ground controllers, and more

BUILD A DOG -BARK INHIBITOR Give yourself and your neighbors some peace and quiet with this training aid that humanely curbs your dog's barking

GERNSBACK PUBLICATION NAVIGATION SYSTEMS TOR YOUR CAR Learn about on -board navigation systems, satellite positioning,

SQUELCH' ° VO roadside beacons, : o E . and more POWER TUNE.

' E

UNDERSTANDING RAMSEY MIÑf1RECEIVÉR -MICROPROCESSORS We all know what microprocessors do, but how many of us understand how they work? Product Reviews 3 NEW FactCards Also: IN THIS ISSUE Scanner Scene Computer Bits 01 Antique Radio Think Tank Radio DX Listening $3.50 U.S. Ham $3.95 CANADA And A Whole Lot More!

71 896 48784 8

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O BP248-TEST BP267-HOW TO BP265-MORE Vii,. i.uww:ur. w BP256-INTRO TO MorAGAetowd EQUIPMENT CON- + Tut Equipment HarbUr IUSE OSCILLO- ADVANCED USES Wesotaw .-w ---.r LOUDSPEAKERS cnnewpdpn warm kluhknehr STRUCTION d otn«Ten SCOPES AND OF THE MULTI - AND ENCLOSURE $5.95. Details con- ~TOM OTHER TEST EQUIP- METER $5.95. Use DESIGN $5.95. We struction of simple. in- MENT $6.95. Mas- these techniques to explore the variety of expensive, but ex- tering the oscilloscope test and analyze the enclosure and speaker tremely useful test is not really too difficult. performance of a vari- designs in use today so equipment. AF Gen, This book explains all ety of components. the reader can under- Test Bench Ampl, Au- the standard controls Also see how to build stand the principles in- dio Millivoltmeter, Tran- and functions. Other ad-ons to extend multi- volved. sistor Tester and six equipment is also de- meter capabilities. more. scribed.

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AmericanRadioHistory.Com JANUARY 1993, VOLUME 10, NO. 1 o _o ec mines THE MAGAZINE FOR THE ELECTRONICS ACTIVIST! CONSTRUCTION ARTICLES BUILD AN AVIATION RECEIVER Fred Blechman 31 Join a growing throng of listening enthusiasts who tune in to the drama of aircraft communications BUILD A DOG BARK INHIBITOR Robert J. Gaffigan Jr. 36 Give yourself and your neighbors some peace and quiet with this humane training aid A TELEPHONE LINE -IN -USE INDICATOR Michael A. Covington 43 Keep others from barging in on your telephone conversations with a simple line -monitor circuit BUILD A WIRE TRACER Charles D. Rakes 45 Cut those tough home -repair and remodeling jobs down to size with this wire -tracing circuit FEATURE ARTICLES ON -BOARD NAVIGATION SYSTEMS FOR YOUR CAR Bill Siuru 39 Satellite positioning, roadside beacons, and other new developments to help drivers stay on course TRACKING DISTANT SIGNALS Laura Quarantiello 47 By monitoring the VHF low-band for skip, you could easily make some wonderful long-distance contacts ALL ABOUT MICROPROCESSORS Timothy D. Green 59 We explore what makes these powerful chips tick in an informative but intuitive style THE CODE MAKERS Larry Lisle 63 Trace the history of code and code -sending gear from the early days to today's computerized equipment PRODUCT REVIEWS GIZMO 5 Spotlight on home theater: Sharp Sharpvision LCD Projector; Carver A/V Receiver; Cerwin-Vega Sensurround Speaker Systems; and much more HANDS-ON REPORT 22 Heath/Reflex Wireless Doorbell PRODUCT TEST REPORT Len Feldman 26 Cannon UC1 8mm Camcorder COLUMNS ANTIQUE RADIO Marc Ellis 65 The Sky Buddy: All together again COMPUTER BITS Jeff Holtzman 67 The XT syndrome CIRCUIT CIRCUS Charles D. Rakes 70 UJT circuits THINK TANK John Yacono 72 RF bulbs DX LISTENING Don Jensen 75 Targeting the world HAM RADIO Joseph J. Carr 80 Some more potpourri SCANNER SCENE Marc Saxon 82 A couple of winners DEPARTMENTS EDITORIAL Carl Laron 2 LETTERS 3 FACTCARDS 49 POPULAR ELECTRONICS MARKET CENTER 50A FREE INFORMATION CARD 51 1992 ANNUAL INDEX 53 ELECTRONICS LIBRARY 84 NEW PRODUCTS 87 ELECTRONICS MARKET PLACE 95 ADVERTISER'S INDEX 98 .... Popular Electronics (ISSN 1042-170X) Published monthly by Gernsback Publications, Inc.. 500-B Bi-Counly Boulevard, Farmingdale, NY 11735. Second -Class 51 postage paid at Farmingdale, NY and at additional mailing offices. One-year, twelve issues, subscription rate U.S. and possessions $21.95, Canada $28.84 (includes G.S.T. Canadian Goods and Services Tax Registration No. R125166280), all other countries $29.45. Subscription orders payable in U.S. tends only, International Postal - Money Order, or check drawn on a U.S. bank. U.S. single copy price 52.95. 0 1992 by Gernsback Publications, Inc. All rights reserved. Hands-on Electronics and Gizmo trademarks are registered in U.S. and Canada by Gernsback Publications, Inc. Popular Electronics trademark is registered In U.S. and Canada by Electronics Technology Today, Inc. and is licensed to Gernsback Publications, Inc. Printed in U.S.A. Postmaster: Please send address changes to Popular Electronics, Subscr'-ption Dept., P.O. Box 338, Mount Morris, IL 61054-9932. photographs return is they rejected. We A stamped self-addressed envelope must accompany all submitted manuscripts and/or artwork or if their desired snould be disclaim any responsibility for the loss or damage of manuscripts and/or artwork or photographs while in our possession or otherwise. I and and As a service to readers, Popular Electronics publishes available plans or information relating to newsworthy products, techniques, ,iclentific technological developments. Because of possible variances in the quality and condition of materials and workmanship used by readers, Popular Electronics disclaims any 1 responsibility icr the safe and proper functioning of reader-built projects based upon or from plans or information published in this magazine.

AmericanRadioHistory.Com Popular Electronics® EDITORIAL Larry Steckler ENE. CET Editor -In -Chief and Puhli.dier EDITORIAL DEPARTMENT A MIXED BAG Carl Laron Editor Since deregulation, cable -TV companies have pretty much Robert A. Young had their way. In most communities, they enjoy a monopoly. If Associate Editor consumers don't like the pricing structure, programming John J. Yacono Associate Editor choices, or have other complaints, they have had little Byron G. Weis, K2AVB recourse except not to subscribe. And while local Associate Editor governments could threaten a poorly performing cable Teri Scaduto Assistant Editor company with franchise revocation, such actions were Kathy Terenzi essentially impractical. The cable industry could operate as it Editorial Assistant saw fit, and without fear. Marc Spiwak Editorial Associate Joseph J. Carr, K4IPV That situation changed somewhat with the passage of the Marc Ellis cable -TV bill Len Feldman this past October. Passed over the veto of Jeffrey K. Holtzman President Bush the bill helps level the playing field a little. Don Jensen Unfortunately, the key words here are "a little." Chris F. O'Brian Charles D. Rakes Marc Saxon Furthermore, the bill is far from Contributing Editors perfect. For instance, the new bill PRODUCTION DEPARTMENT provides some limited rate relief. It allows the FCC to Ruby M. Yee regulate only the most basic tier of programming; the FCC has Production Director no input on other rates unless it receives complaints from Karen S. Brown consumers, municipalities, Production Manager etc. Marcella Amoroso Production Assistant Also important is a provision calling for cable systems to be Lisa Rachowitz technically compatible all Editorial Production with TV's, VCR's, etc. Except where off-premises ART DEPARTMENT descrambling is used (and currently few Andre Duzant operators use that technology), most scrambling techniques Art Director render features such as picture -in -picture essentially useless Injae Lee (unless Illustrator additional descramblers are rented). Unfortunately, it is Russell C. Truelson unclear how this provision will be interpreted (perhaps it will Illustrator give life to the ETA's multiport standard?), and it is vague Jacqueline P. Cheeseboro enough to give operators the leeway they need to skirt it with Circulation Director little imagination. Michele Torrillo P-E Bookstore Somewhat troubling is BUSINESS AND EDITORIAL OFFICES a provision that allows TV broadcasters to charge Gernsback Publications, Inc. cable companies for use of their signals. It ignores 500-B Bi-County Blvd. the fact that broadcasters already receive value for their Farmingdale, NY 11735 in 1-516-293-3000 signals terms of higher viewership and, hence, higher Fax: 1-516-293-3115 advertising revenues. Worse, intertwined with modified must - President: Larry Steckler carry regulations, it could tax the channel capacity of older, Customer Service/Order Entry smaller systems, or deprive viewers of channels they desire. 1-800-827-0383 7:30 AM - 8:30 PM EST This provision was unnecessary, and could be a source of Advertising Sales offices listed on page 98 trouble in the years to come. Cover photography by Denny Bailly/Unicorn Stock Photos and Diversified Photo Services In short, all the sound and the fury aside, the bill appears to Composition by be a mixed bag. Its benefits will largely depend on how, and Mates Graphics how vigorously, the FCC chooses to implement and ,e, ABC enforce its AUDITED provisions. But at least it's a start.

Since some of the equipment and circuitry described in POPULAR ELECTRONICS may relate to or be covered by U.S. patents, POPULAR ELECTRONICS disclaims any lia- bility for the infringement of such patents by the making, using, or selling of any such equipment or circuitry, and Carl Laron suggests that anyone interested in such projects consult a 2 patent attorney. Editor

AmericanRadioHistory.Com MUDDLED MESSAGE I'm writing concerning a minor LETTERS problem with the "Personal Message Recorder" project -r. (Popular Electronics, October 1992). As described on page 40, the electret microphone must be tied to analog ground, 0.1-µF capacitorshave been in- extra energy that the old point/ materials. The plug wires have but according to Fig. 2 (sche- terchanged. The part Kettering ignitions weren't in- thicker, better insulation and matic diagram) of the article, designated Cl is actually C2, tended or designed to handle. thicker boots (8mm plug wires there is no such connection. C2 is C3, and C3 is Cl. In any ignition that has a 40kV are used in the late -model igni- The correct connection is C.B. or higher peak output voltage, tion systems, compared to 7mm shown in Fig. 1 here. There is Brooklyn, NY the distributor cap, rotor, plug wires with thinner boots that are wires, and plug -wire boots must usually used on point/Kettering HIGH-ENERGY, HIGH - be designed with sufficient in- systems). U1 RISK IGNITION sulation and high dielectric On cars having OEM sup- ISD1016 C2 strength materials, to withstand pression plug wires, those wires 1 "Build A the high voltages at automotive should be replaced after about MIC 17 Charles Ball's article, R3 High -Energy Ignition System under -hood temperatures. To four years or 35,000 to 40,000 MIC1 10K For Your Car" (Popular Elec- prevent problems with ionization miles, as the carbon core in +5V tronics, September 1992) and crossfire between adjacent them doesn't last much longer R2 than that. When the wires go 2.2K appears to be a good article in terminals, most late -model high- general, but makes a few risky energy ignitions use distributor bad, the electricity may find a assumptions that must be point- caps with wider spaced termi- path to ground through the in- Fig. I ed out to your readers. nals, many are vented, and sulation. You should use high - First, retrofitting a high -output most are made of better insulat- quality plug wires of suppres- also a problem with the parts - ignition on an older car requires ing material. The rotors are sion core, wire -wound placement diagram (Fig.4). The that the entire ignition system correspondingly redesigned and suppression type, or (where designations for the three be capable of handling all that made of high dielectric strength legal) copper -core wires made

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AmericanRadioHistory.Com by "hot rod" after-market ignition time to rival some capacitive - oil -filled monster that I had re- including a potentiometer for

makers such as Accel, Mallory, discharge ignitions. built at a local transformer adjusting the flicker rate. I prob- Jacobs, Moroso, or MSD. The J.M.N. company. The transformer was ably still have a few of the distributor cap and rotor should Donora, PA originally from a surplus ground - lamps and other components in be similarly upgraded to high - based military radar: 18,000 my junk box.

quality after-market parts. A TESLA COIL ADDICT volts, 220 milliamps. I had to Serving as the Electronics Of- Second, Mr. Ball assumes use a 3000 -watt clothes dryer ficer on board the USS that higher spark energy auto- I really enjoyed the "Circuit Cir- as a current limiter because the Saratoga, I made a flashing

matically reduces emissions, cus" column entitled "Fun With 100 -amp circuit breakers I used symbol of an electron to hang

but the degree of emission re- Tesla Coils" (October 1992). as "on/off" switches could not over my desk. First I made two ductions really depends on built the Tesla coil oscillator and handle the primary current of loops of #12 wire with the many variables such as ignition was surprised that the coil actu- the transformer! largest dimension being 8 timing -advance settings, car- ally produced a significant (P- All that work, time, and inches. I soldered the body of

buretor air/fuel ratio, cam -shaft inch arc) output with such a money, and I was never able to an NE51 lamp to the loop. I timing, etc. The air/fuel ratio small input signal. I am currently achieve resonance! I was more soldered a capacitor in parallel should be set with the aid of an modifying the circuit to drive the disappointed in the failure of with the lamp and used the emission analyzer for best re- primary circuit of my standard that Tesla coil than I was in the resistor to complete the circuit

sults. Tesla coil, with the intent of failure of my first marriage! A to the other loop. I used #32 Third, ignition energy may not using the solid-state circuit to couple of years later, a water wire to support the loops from a necessarily improve from the help me optimize capacitor/in- leak in a storage building ruined battery lying in the cables in the addition of a capacitive -dis- ductor values in my Tesla coil's the secondary-a very sad overhead. It looked like it was charge ignition box alone if the primary/secondary circuit. sight, indeed. floating in the air and blinking at

original coil is not up to handling Because I used open con- I am currently trying to locate the same time. After I had it

I the job. Most ignition coils de- struction when I breadboarded as much "practical" information wired and working, sprayed signed for point/Kettering or the oscillator circuit, using no on Tesla coil tuning, con- the components with gold -col-

conventional (non -capacitive RF shielding, I managed even- struction, etc., as possible. ored spray paint, masking the discharge) electronic ignitions tually to fry all my in -stock 567 Anyone who has spent any lamps first, so nobody could have higher inductance, es- chips, as well as two or three time building Tesla coils knows see what the values of the parts

pecially primary winding voltage regulators. I am going to that they are addictive, and that were. inductance, than coils specifi- go to a 555 timer chip circuit they can be the most challeng- R.A.N., LCDR USN, Ret. cally designed to give maximum because that chip is more reading, frustrating, yet exciting Brunswick, GA output with capacitive -discharge ily available at my local Radio projects that a person can build.

(or CD) ignition boxes. To en- Shack store. You can be sure I think the article will help in HAVES & NEEDS

sure maximum output you that I am also going to shield future Tesla-coil projects, and I

should use a CD -compatible ig- this thing! encourage Popular Elec- I am looking for a schematic of nition coil with a CD ignition My biggest surprise was just tronics to publish more Tesla- a Model 700 DF -AF crystal unit. Those after -market ignition how sensitive these coils are related articles. In fact, if you marker/TV generator made by coils have better insulation to when it comes to setting them were to start a Tesla project the Electronic Measurements

protect against internal coil to resonant frequency. They are construction magazine, I'd be- Corporation. I am also looking shorts at very high output volt- very, very touchy. come a charter subscriber! for a VN1OK MOSFET tran-

ages for which OEM coils aren't I have been building Tesla B.P. sistor. Thanks. usually designed. coils since 1965 (prompted by, Irving, TX David L. Murphy Fourth, while CD ignitions coincidentally, a Tesla-coil proj- 4948 Caribee Drive boast extremely fast voltage rise ect in the July 1965 issue of DOWN MEMORY LANE St. Louis, MO 63628

time and high output voltage, Popular Electronics). I have yet

you must consider the imped- to build that one special "big Reading the article, "Build the I own a Sansui SR -838 turnta- ance through which that voltage one" that most coil builders Idiot Box" (Popular Elec- ble. Last year it lost speed

is measured. Voltage measured dream about, although I really tronics, September 1992), sent control and strobe. I have tried on a high secondary side im- gave it a good try several years me hunting through the attic for several "so-called" Sansui ser-

pedance can be very high, but ago. a similar device that I made in vice centers in the local area for

current delivered to the plugs That attempt was a Tesla coil 1952. I found it, and it still repairs. All claim to provide will be low. Spark plugs and that had a primary nine feet in works. prompt and professional service

wires with lower resistance or diameter and a secondary 18 I made mine with 100 lamps of Sansui products; however, I impedance will "load" the coil's inches in diameter. The 52 -inch mounted in shallow holes in a have had no success. output and lower the voltage tall coil was space wound with square of plexiglass. It was Please help me find someone output measurement, but plug over 4700 feet of 24 -gauge wire, made to be hung like a picture in my area that will service this

current will be higher. Total en- sprayed with 24 cans of acrylic from the wall and was AC turntable. I am willing to pay the ergy output is voltage x plastic. The primary coil was powered. It served as a night cost of shipping, if necessary,

amperage x time, and many tapped, of course, but I could light and for entertainment for since I am not ready to trash the CD ignitions produce sparks of also precisely tune it by a me- two small children. turntable. shorter duration than conven- chanical arrangement that In 1952 you could buy bags of As a final alternative, I'd ap- tional point/Kettering or varied the spacing between surplus components at a very preciate if someone could send

electronically switched ignitions. turns-no mean feat on a coil low cost. I believe I purchased me a copy of the schematic and

In fact, some conventional elec- the width of my garage! 200 capacitors for less than $3, parts list for the SR-838, and I

tronically switched ignitions with The capacitor was an oil -filled and I got the same number of will attempt to repair it myself. suitable high-performance coils glass -plate job, which weighed 10-megohm resistors for even Arthur Alston can produce sparks of sufficient almost 700 pounds. The trans- less. The circuit is identical to 1468 Key Parkway, Apt. 302 voltage, current, and duration former was a 4-kva, 300 -pound, the one shown in the article, Frederick, MD 21702

AmericanRadioHistory.Com JANUARY 1993

VOLUME 6, NUMBER 1 A CHRONICLE OF CONSUMER ELECTRONICS

Spotlight on Home Theater

We have to admit that we love poring through the glossy pages of Audio/Video Interiors and other high -end magazines, ogling custom A/V installations that are as expensive as they are visually, audibly, and -r-b» `19 aesthetically pleasing. Ten-foót screens gracefully descend from the ceiling, motorized panels slide back to reveal a huge back -projection TV, speakers are re- *Cif II cessed into the walls, touch -screen computer monitors control a dozen different Al ir 3 . V "zones." One recent issue featured a custom installation in which the equipment included 97 in -wall speakers plus

r _IL . three other pairs, two amplifiers, a re- 11.44 ceiver, two tuners, a CD player, a cassette deck, assorted remote equipment to route the audio and video throughout the house, . - .; four VCR's, a seven -foot front projection TV, a 50 -inch rear-projection set, and 18 (yes, eighteen) 20 -inch TV's! processor, and speakers. Sounds simple WHO, WHAT, WHEN, WHERE? Time for a reality check: If we tried to enough, right? The problem is that be- It's easy to imagine all the things you'd put all that equipment into our house, tween'that basic installation and the like your home theater to have. But it's there would be no room left for the family, custom dream job described above, there important not only to determine what you let alone furniture, clothing, and other , lies a whole world of options and, alwide want from a home -theater system-but basic necessities. In fact, it's unlikely that range of prices. Deciding what sort of also to make sure than your dreams are our house is worth as much as was paid for components would work best for you is no compatible with your home, your family, that custom installation!_ easy task. _ and your wallet. Ask yourself the follow- - factors to be consid- ing questions before making any purchase . That's not to say that average people There are several can't incorporate, some of the ideas and ered before you venture out shopping and decisions: technology represented in that "dream in- get en more confused by fast -talking Who is going to be using the home - stallation" in their own relatively modest - sales people. Money, of course, is a major theater system? If you're an electronics homes, keeping within their own rela- concern. But "bargain" and "value" are enthusiast, and no one else will be touch- tively modest budgets. In this month's totally different concepts. What might be a ing the controls, then simplicity won't be a up a high priority. Chances are, however, that - Gizmo, we'll take you oh a tour of home. real deal for someone-grabbing- theater-what it means, what's required, sale -priced ,low -end A/V receiver, or everyone in the family will want to use the what's optional, and how you can make it skimping on the speakers, for instance- system. If no one can figure out how to work in your home. Then 'we'll take a look could ruin the whole home -theater experi- switch functions, there will be a lot of at several products that you might consider ence for someone with more sophisticated grief-for you as'well as everyone else. integrating into, your own home -theater ears. That's not a good value at any price. When are they going to be watching it? setup. In a similar vein, you might decide to go Daylight conditions aversely affect front - The goal of any hometheater, of course, all out and splurge on the biggest screen projection systems and, to a lesser extent, is to recreate the video and audio sensa- available ("If I'm going td do it, I'll do it rear -projection sets; a direct -view --set tions experienced in a movie theater (or right!"), only to get it home and discover would be a better choice for those who concert hall, or sports arena, depending on that it's much too large for comfortable watch TV during the day, or who prefer to your viewing tastes) as closely as possible viewing in your home theater. keep some lights on in the room. in the home. Doing so requires., at the very= - leaSt, a large -screen stereo. television, a TURN PAGE FOR CONTENTS stereo VCR, some sort of surround -sound 5

AmericanRadioHistory.Com We'll discuss component, speaker, and bly the same distance behind the viewers furniture placement later in this article. as the front speakers are forward, although What will you be watching? Do you time -delay circuitry in a surround pro- pi -der live performances of opera and sym- cessor lets, you mount the rear speakers phonies, or action films like Terminator closer. A second set of surround speakers This II? Sporting events, or foreign films? Net- might be necessary in very deep rooms; work sitcoms, or nature shows? All of the they should be placed at the sides of the above, and then some? room. The subwoofer can be placed any- month How can your existing components be where in the room, and many are designed integrated in the new system?It's often not to slide out of view under a couch or chair. in necessary to buy all new gear. Use your For room -shaking bass, you'll probably existing TV or hi-fi VCR and put the want a separate amp to drive the sub - money you would have spent toward a bet- woofer. ter A/V receiver; you can always upgrade That much equipment can overtake a the other pieces later. small room, and push other activities to GIZMO. What wiringlinstallation skills do you the background. To avoid conflicts with possess? Will you have to call in a pro -to decor and retain the use of the family room set up your home theater, or can you han- or living room for more than watching dle the connections on your own? If you movies, you might consider converting a decide that you need help with all or part of previously unused area of your home for the job, or with selecting the components, use as a home theater. A basement, attic, Spotlight on Home Theater pg. 5 you might want to consult an audio/video or attached garage that you wouldn't con- installer (who should ask you some of the sider prime living space due to lack Sharp XV-H3OU SharpVision LCD of same questions we are). windows and/or lower than normal ceil- Projector pg. 12 How much can you comfortably afford ings just might be ideal for a home theater. Carver HR -894 NV Receiver with to spend on a home -theater system? A The natural dimness is a plus, and because Dolby Pro Logic pg. 14 well -planned home -theater can provide you'll spend virtually all your home -the- your family with hours of inexpensive en- ater time seated, the only worry with low Cerwin-Vega Sensurround 7 -Piece tertainment. But if you have to take a sec- ceilings is speaker placement. And if Speaker System pg. 16 ond job to pay for it, you won't have any you're handy with tools, finishing a pre- Toshiba CD/CDV/LD Disc Player time to enjoy it! viously unfinished space would also give Model XR-W70A pg. 17 you the chance to create your own custom THE HOME -THEATER installation. Bose Home Theater System pg. 20 ENVIRONMENT Instead of using a separate space, it Mitsubishi Pro -Logic Surround -Sound Although home theaters can come in all might be possible to use the same space at System pg. 20 shapes and sizes, there are some basic different times for different purposes. rules that should be followed, although Panasonic Rear Projection TV pg. 20 Front -projection setups are particularly they aren't written in stone. Figure 1 illus- well -suited for home theaters that must Zenith/Bose Surround -Sound trates the recommended arrangement of disappear when not in use. It's often possi- TV pg. 20 furniture and components. If there are ble to mount the projector unobtrusively plenty of windows, special curtains or on the ceiling (in custom jobs, you can Gizmo is published by Gernsback Publica- shades might be required to give you better even have the projector recessed into the tions, Inc 500-B Bi-County Blvd., Farm- control over the room lighting. Carpeting ceiling on a motorized lift), and some ingdale, NY 11735. Senior Writers: Chris F. is recommended to minimize the reflec- manufacturers offer projectors that have O'Brian and Teri Scaduto. Contributor to tion of sound. The minimum distance been factory -mounted in coffee tables. this issue: Frank Barr, APEL. ©Copyright from the couch (or recliner) to the screen Ceiling -mounted screens roll up and out of 1992 by Gernsback Publications, Inc. should be 2-3 times the screen size (mea- sight when not in use. Today's in-wall Gizmo is a registered trademark. All rights sured diagonally). It; for instance, your speakers and a sub - reserved. are almost invisible, sofa is 12 feet from the television, the ideal woofer can be easily tucked out of sight. screen size would be 48 -72 -inches. In Such a set-up allows you to use your living general, projectors need to be placed at a room or family room for everyday ac- distance of about 1' times the diagonal tivities, until it's time to "raise the cur- Where is the system to be placed? Do screen size. (One exception to that rule is tain" on your home theater. you have a room available that can be used the SharpVision reviewed in this issue, A friend of ours built an innovative solely for home theater? Most of us don't which requires somewhat less space be- home -theater setup (shown in the opening have that luxury. If the system will be set tween projector and screen; be sure to fol- photo) in a room that measures about up in the living room. there probably will low the manual's recommendations.) 14 x 22, with only one small window on be restrictions due to decorating concerns. Chairs and couches should be set up so one of the short walls. He replaced that one If it's in the family room, keep in mind the that the viewing angle doesn't exceed 30°. with an 8 -foot -wide picture window. other activities carried out there-doing Speaker placement requires the center Ranking the window, he built floór-to- homework or school projects, listening to speaker to be as close as possible to the ceiling, I8 -inch deep shelving units; under music, paying bills, reading the paper, screen; magnetic shielding is essential to the window is an upholstered window playing board games. Again, keep in mind avoid distortion to direct-view screens. seat-a feature that his wife had always the lighting required for those other ac- The front speakers should be placed to wanted. Ceiling mounted in front of the tivities. either side ofi and at an equal distance window is a video screen. A Vidikron What size is'the room? A screen that's from, the screen; again, shielded speakers projector is mounted on the ceiling above too small can get lost in a large room; a will likely be required. The surround the couch. Assorted components-VCR, screen that's too large can be even worse. speakers go behind the viewers-prefera- Pioneer laserdisc player, Fosgate Pro-Log-

AmericanRadioHistory.Com WHAT TO LOOK FOR IN HOME -THEATER COMPONENTS

Televisions and Monitors. First, make highest -contrast picture, you'll want a should be able to find one at a bargain sure the stereo TV or monitor you direct -view monitor. Rear-projection price these days. choose is the right size for your room. sets are a compromise between the If money is not an issue, you'll want Keep in mind how big that 27-incher two. LCD projectors can't match the equipment that has Home THX cer- looked when it replaced your old 21 - three -tube projectors-yet. But if you tification. Such equipment must receive inch set-TV's seem to shrink with time. need huge -screen portability, they're an official OK from Lucasfilm, Ltd., the At the same time, you might want to the only way to go. same people who certify THX movie bring along a tape measure to make Don't forget to listen to your display theaters. In short, Home THX certifica- sure that that huge rear -projection set device, too. Many sets provide good tion is a sort of performance guarantee. will fit through your door, and not take up enough sound that you might be willing Speakers. Speakers are arguably the too much floor space once it's in. Some to forgo a separate audio setup. Some most difficult components to choose for manufacturers, Mitsubishi, for one, are provide traditional surround sound. a home -theater system. The only fea- now making slim -line rear-projection Others might use. two -speaker "sur- ture that counts is how they sound..That sets that take up surprisingly little round" systems, such as Carver's Sonic means that only you can choose the space. Holography or Hughes Sound Retrieval speakers that sound best to you. Mak- The overriding factor in determining System. ing your decision more difficult is the the largest screen size you should use VCR's. VHS, stereo, and hi-fi are the fact that speakers sound dramatically is how far away from it you're going to sit. three most important things to look for in different depending on their placement You want to see the picture, but you a home -theater VCR. Yes, we know that and your home-theater acoustics. Nev- don't want to be able to see all of ;he the S -VHS format will provide better res- ertheless, there are some general elements that make up the picture. If olution. But if you can't rent tapes-and things to keep in mind as you shop. you sit too close to a screen-no matter if you don't have a S -VHS camcorder- If your home theater will use a direct - what its size-you'll start to see the h; ,:- who cares? view screen; your front speakers must zontal line structure of the TV picture. Do you use a VCR to watch scenes in be magnetically shielded. The purpose (Some display devices, the Sharp LCD slow motion or to watch still pictures? of Pro -Logic decoding is to place projector that we review in this issue, You need a four -head deck for those sounds accurately. Your front speakers add their own visible structure as well.) special effects. Otherwise, a two -head should be directive, so they won't mud- If you want to get that true movie - deck should do you fine, and merely dy the directional information. The sur- theater feeling-where the screen fills a provide a somewhat worse picture round speakers are meant to provide large percentage of your field of view- when you're fast -scanning over all those "fill" sound. They should provide wide you might be able to ignore the line commercials. Do you edit tapes? A fly- dispersion of the sound. structure and sit closer than the recom- ing erase head will help you obtain We generally prefer using three mended 4-8 times the picture height. seamless edits, and audio/video dub- matched speakers for the front. If you Usually, though, you'll have to move bing will let you add something to your must scrimp, get a cheaper center - back. You don't want a bigger picture, edits. Do you use a VCR extensively for channel speaker. You might also be you want a better one. time shifting, including when you travel? able to economize on the rear speak- Let's look at what this means in real Easy but sophisticated programming ers. Many speaker manufacturers have numbers. A 50 -inch (diagonal) screen features are what you should be looking made things easier by selling complete has a picture height of 30 inches. (Re- for. surround -sound speaker packages. member: the aspect ratio of a TV screen Don't forget the little things that can Laserdisc Players. For the highest -qual- is 4 x 3, so the diagonal measurement is make a VCR special. A 30-second skip ity video and audio playback, you need the hypotenuse of a 3-4-5 triangle. If you feature makes bypassing commercials a laserdisc player. Don't forget that vid- can remember some high-school ge- a breeze. Timer backup lets you laugh eo quality becomes more important ometry, you can calculate the picture at intermittent power outages. And you with a large -screen home theater. The height once you know the diagonal might consider buying the same brand relatively recent growth of large -screen measurement.) A viewing distance of 10 TV/monitor and VCR, for the matching sales might be why it's taken about fif- feet would be required for best viewing remotes that many brands offer. teen years for laserdiscs to catch on. of the 50 -inch monitor. A/V Receivers. An NV receiver can Are videodiscs for you? Since vid- . Some projection sets suggest that be the nerve center of your home -the- eodiscs are still difficult to rent (but gen- you can sit at 11/2 to 2 times the picture ater system and will provide a conve- erally becoming less difficult), you height from the screen. They usually nient link to your audio components. might be disappointed with a player have a "soft -focus" setting that exagger- Make sure your A/V receiver provides that sits idle most of the time. But if you ates the width of the horizontal lines. If sufficient switching capability. You'll like the idea of a video library-and one you can afford the $20,000 price, Farou- want an easy way to dub audio and that will last, presumably, forever-then jda Laboratories has a line -doubling video sources, and you'll want everyone laserdiscs are tough to beat. Here are a system that lets you get as close as you in your home to be able to use it as well. few things to keep in mind as you shop. would to a movie -theater screen. Many people find that on -screen dis- If you plan to use your home theater. A laserdisc, which produces the plays make the setup easier. for audio as well as video, a combi play- highest -resolution images of any con- Good sound can draw you into a er-which also plays CD's-is impor- sumer video device, has a horizontal movie even faster than a teriffic picture. tant. Almost all videodisc players you'll resolution of about 450 lines. Think For most applications, Dolby Pro -Logic find will offer that capability. Most will twice before you consider a monitor or capability is what you want. The added play only a single disc..Others provide a projector that offers less. You'll likely center channel of a Pro -Logic amplifier, 5 -disc CD changer. see many projectors and direct -view and the active sound -steering circuitry, A feature we think is important is auto- sets touting much higher resolution. provides a more realistic theater-like matic side -changing. Having to get up But the picture on a projector-front sound. to flip over a disc reminds us too much or rear-with a horizontal resolution of If you must stay on a small budget: of the days of the LP! Digital effects, 500 lines won't look the same as the one consider a standard Dolby Surround available on most higher-priced units, on a direct view set with a 500 -line hori- (not Pro -Logic) amplifier. It won't com- can add usable scan and still modes to rEl a Pro amplifier CLV discs. (CLV discs have longer play- zontal resolution. That's because the pare favorably to -Logic :i contrast and brightness will vary. in accurately placing and tracking ing times than do CAV discs, but they For the largest picture, you'll need a some of the sound, but you might well require digital effects if pictures are to front-projection unit. For the brightest, be happy with it-especially since you be scanned.)

AmericanRadioHistory.Com A/V RECEIVER AND AMPLIFIER THE HEART OF LASERDISC PLAYER HOME -THEATER SOUND. FOR THE ULTIMATE LOOK FOR PRO -LOGIC VIDEO PLAYBACK FORMAT. DECODING AND CURTAINS/DRAPES TWO-SIDED PLAYERS OFFER AMPLE SWITCHING FOR THE MOST THE MOST CONVENIENCE CAPABILITY. PLEASING PICTURE, VCR YOU NEED TO HAVE HI -F1 STEREO OTHER AUDIO EQUIPMENT CONTROL OVER SOUND A MUST. A GOOD HOME THEATER ROOM LIGHTING. FOUR HEADS ISN'T JUST FOR REQUIRED FOR GOOD VIEWINGI SLOW-MOTION AND STILL -PICTURE PLAYBACK.

TV/MONITOR FRONT SPEAKERS THE FOCUS OF THE RIGHT- LEFT - ANY HOME THEATER. AND CENTER -CHANNEL BIGGER IS BETTER, SPEAKERS SHOULD BUT TOO BIG IS BE MATCHED FOR BEST NO GOOD. CHOOSE PERFORMANCE. THEY MUST BETWEEN DIRECT VIEW, BE MAGNETICALLY REAR PROJECTION, SHIELDED IF THEY ARE OR FRONT PROJECTION. MOUNTED NEAR A DIRECT -VIEW SCREEN.

SUBWOOFER YOU'LL WANT ONE FOR ROOM -SHAKING SOUND. A SUBWOOFER CAN BE MOUNTED ALMOST ANYWHERE IN THE ROOM. YOU MAY NEED A SEPARATE AMPLIFIER TO DRIVE IT.

UNIVERSAL REMOTE ESSENTIAL FOR CONVENIENT ACCESS TO PROJECTOR YOUR EQUIPMENT FOR THE LARGEST FROM YOUR VIEWING PICTURE, YOU NEED LOCATION. A FRONT -PROJECTION PRE-PROGRAMMED ¡¡` SYSTEM. l` AND LEARING REMOTES ARE AVAILABLE.

SURROUND SPEAKERS FOR THE MOST BELIEVABLE 'FILL" SOUND MOUNT THE SPEAKERS AS FAR TO THE REAR AS POSSIBLE

Shopping for a home -theater system can be ea intimidating If you're confused about the é basics. This illustration, which shows the principle elements of any home theater, CCI provides a starting point. ovF º is surround amplifier -fit neatly on a The first time we saw the room, we excellent audio and video reproduction, built-in component rack. Infinity speaker weren't aware that it doubled as a home - and comfortably attractive surroundings. w fit n the new shelves; the center channel is theater. But later, watching a football game When it's not used as a home theater, the 3 mounted inside the window seat, with and a few scenes from Robin Hood: Prince room benefits from added light, extra stor- áonly the grille showing. The subwoofer is of Theives, we realized that it was one of age space, improved proportions, and at- mounted under the floor-a heating grate the best setups we've ever seen. The de- tractive new seating-all thanks to a 8 lets the bass into the room. sign represents the best of both worlds- thoughtful home -theater design.

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AmericanRadioHistory.Com CALL IN THE PRO'S If you're not handy with wiring or with tools, or if you want a system with a ceil- Look Sharp! ing-mounted projector and a motorized screen, it might be wise to call in a spe- SHARPVISION XV-H3OU HIGH - cialist. CEDIA, the Custom Electronic BRIGHTNESS LCD PROJECTOR. From: Design & Installation Association, can Sharp Electronics Corporation, Sharp supply a list of professionals in your area Plaza, Mahwah, NJ 07430-2135. Price: (1-800-CEDIA30). They don't work only $3995. for millionaires; in fact, according to a responses to a recent CEDIA poll of its Dedicated Gizmo readers might recall members, the "average" job for a custom our May 1991 review of the Sharp XV-100 installation company can range from $400 LCD front -projection TV. To recap: The to $60,000. You can hire a professional to XV -100, weighing just over 31 'pounds, do it all-select the components, design had the advantages Fisher A/V Component System of portability and easy the installation, hire and supervise cab- set up. We put it through its paces, bring- inetmakers and electricians, and calibrate ing it with us to a ski house in Vermont, the finished system. Many custom -in- piifiers'.for a bone -rattling total of mire and making it the "guest of honor" at an stalled home -theaters are just a small part than 1400 watts, direct radiators for music impromptu Super Bowl party. The large- of whole -house, multi -zone audio -video playback, and a compression driver horn screen experience was vivid enough to systems (which is a topic that we'll cover combination for video plzybáck. JBL's make up for a picture that, while quite in a future issue of Gizmo!). But you can aimvis tó provide a complete home -theater impressive for a portable projection sys- also hire a custom installer to consult on a ekperienee that accurately reproduces tem, left some room for improvement. small project, and some will even come in movie soundtracks, but not compromise At the last Consumer Electronics Show, just to properly set up the components music listening. To that end, the system demonstrations of Sharp's latest LCD you've purchased. offers two modes. For home -theater use, projectors suggested that some major im- Synthesis; is THX licensed and approved provements had been made in the past cou- FOOTING THE BILL and offers Dolby Pm Logic and ten sup- ple of years. We arranged to try out the XV- So, what you can realistically expect to plementhty surround settings. -Switching H3OU in a home -theater setup. spend on a -home -theater system? The to the music mode disconnects the center Physically, the XV-H3OU somewhat re- high -quality setup we that review hi this and surround loudspeakers and replaces sembles its predecessor. It's even easier to LCD issue-Sharp projector, Carver Dol- them with components specifically de- carry around or store out of sight when not by Pro -Logic A/V receiver, Cerwin-Vega signed for audio sound systems. The sug- in use, now that close to ten pounds have -piece seven Sensurround speaker system, gested price, which doesn't include" a been knocked off-the XV -1130U weighs and Toshiba laserdisc a total player-has video source (VCR or laserdisc player) or only 23 pounds. At the top of the unit is a suggested retail price of $6958.95, not installation (which must lie: done profes- carrying handle; an on/off button; indica- counting the screen. (We used our own sionallyii is $47,900. tors for power, temperature, and lamp re- VCR and an extra to the amplifier drive placement; and a cover that flips open to subwoofers.) reveal controls for the adjustment of'the Of no one course, who shops carefully projector's picture and audio. That's one ever pays the full suggested retail price; it major improvement-unlike the XV-100, pays to shop around. Learn what features the new SharpVision is equipped with its on each are component essential, and own audio amplifier and matched stereo which are icing. just speakers built in. In some installations, Shopping is made that much easier if those top -panel controls can be difficult to you decide to go with a pre-packaged sys- -, Y.r.. access. But that's not a problem, since the tem that includes all or most of the re- XV-H3OU comes with a remote control, quired audio and video components. For another convenience missing from its instance, Fisher's 9235AVX A/V compo- predecessor. Jacks at the rear of the unit nent system includes a 27 -inch television, provide audio inputs frbm two sources, a 120 -watts per channel receiver with Dol- J81 Syntesis One Home-Thea-er audio output, one S -Video and two video System by Pro Logic, a five -disc CD changer, a inputs, and a video output. The back of the double cassette deck, and five speakers. unit also has a cooling fan; the air intake Also included for a suggested price of Whether you decide to go the pre-pack- fan is located on the side of the projector. $2199.95 is a unified remote control that aged rotate, or purchase individual compo- The XV-1130U still uses basically the can also operate Fisher VCR's, and a light - nents, good shopping skills are important. same LCD technology, with some refine- oak -finished cabinet. Similar systems are 'Determine precisely what features you ex- ments. The projector uses three LCD pan- available from several manufacturers; pect from each component, and then look els, a series of mirrors, a bright, metal - most include TV's that have a relatively for prodrets in your price :tinge that offer halide bulb, and a quality lens to project small screen size-generally, 26 or 27 those features. Scan the circulars that the image. One LCD is provided for each inches. come in -your Sunday papa and read con- color component of a TV picture: red, At the opposite end of the pre-packaged sumer Magazines. Then go out to each of green, and blue. The LCD panels them- spectrum is JBL's Synthesis One, which the electronics stores iri your area to com- selves provide no color information. They includes a front projector, a screen, a video parison shop. transmit or block the colored light that is controller, signal -processing equipment, That's just what we did, and we found fed to them. The light from the metal - multi -component loudspeakers, cross- some affordable. and some interesting, halide bulb is separated into the red, overs, equalizers, a surround -sound pro - .home -theater alternatives=including a green, and blue components by dichroic 12 censor, dual 18 -inch subwoofers, six am - (Continued on page 17) mirrors, which are special mirrors that re-

AmericanRadioHistory.Com Using the pattern makes accurately focusing the projector much easier. Our home -theater system-the Sharp - Vision Projector, a Carver A/V receiver with Dolby Pro -Logic, Cerwin-Vega's Sensurround speaker system, and a Toshiba laserdisc player-was installed in a room measuring just 16 x 14 feet. The room was pretty crowded before we un- packed the screen provided by Sharp (sold separately from the projector). On a tripod stand, the screen stood out a couple of feet from the wall, while the projector was set up about a foot from the opposite wall. That left a space of about 13 feet-too short to use the projector to its full 150 - , -.4. inch picture potential. In fact', in such a small room, we were more comfortable with the picture size set to about 70 inches or smaller, although the manual said that 100 inches would' be fine at that distance. The screen does make a difference in picture quality, but it simply took up to much space. Because of that, we found ourselves frequently watching videos on a bare white CIRCLE 50 ON FREE INFORMATION CARD wall instead of bothering with the screen. Watching movies on the large screen (or fleet light of one color while transmuting because a:close-focus lens lets you view a on the white wall) was a treat once the with all others: 150 -inch 'picture :from just over 18 feet picture was adjusted properly. As any from about 12 large projection TV, you have to be careful - Each LCD panel contains 112,320 pix away, or a 100 -inch picture els (for a total of 336,960 pixels). That_ feet. And once the unit is connected and not to make the image too large or you'll of the picture. translates to a horizontal resolution of 4001: '- the screen size selected, the remote control see the line structure lines, compared to the XV -100's 300. allows "you to conveniently adjust the pic- (Large -screen projectors are one reason In addition, the SharpVision XV ture without leaving your seat. we "need" HDTV.) With the Sharp proj- H3OU's high-intensity metal -halide Tamp Front -projection systems do demand ector, you can also see the individual pix- generates up to 800 lux of projected darkened viewing conditions, and Sharp els that make up the image. The only real unit, brightness at a 40 -inch screen size. That wisely supplies a lighted remote control. complaint we had with our sample brightness level decreases slightly as the The buttons_ don't remain lighted at all however, was that the picture brightness picture size is increased. And you can da °times; pressing any button or the illumina- was not consistent over the entire screen- we quite a bit of increasing=the maximum tion switch located on the side of the re- there were a couple of "hot spots' that screen size is 150 inches diagonally, `com- mote causes all the buttons to light for found disturbing. i pared to the XV -100's 100 -inch maximum. about five seconds. The remote can be For everyday "background" television The XV -1130U also offers viewers the op used to control power and, volume, select viewing, we found ourselves switching lion of using ít as a rear projector the video input source, and adjust the vid- back to our 27 -inch set that happened for a using a mirror to reflect the image to the eo and audio. On -screen displays make it couple of reasons: First, viewing the screen -simply by flipping the reverse-_ easy to "adjust the. picture, brightness, smaller set doesn't require a darkened image switch. color, -tint, sharpness, treble. bass, and room, and we like to read the paper or do puzzles while watching. Sec- , The differences between new and old balance. _The remote control also can'be crossword models are immediately obvious. With no used to mute the sound, and to set a sleep ond, most network -TV shows just don't external audio source required, hookup is timer to tum the projector off after 30, 60, have enough substance to warrant such a ° even easier. All that's required is connecl 90, or 120 minutes. big picture. After all, 'Rosanne and Dan lion to a video source (laserdisc player or We,got á lot of use out of the remote Connor and family are bigger than life VCR) via the supplied audio and video picture -adjustment capability because`the even on the small screen! (And their whin- cables.; While that's perfect for large displayed image never seemed to.be con- ing is not enhanced by surround sound, screen portability, you wouldn't be happy " sistent. We found ourselves continually either.) with the sound in a home -theater installa- changing the brightness, sharpness, and But when it came to movie -watching, the large picture lent a whole new dimen- tion, where you'd want to connect the - color to get a watchable picture depending projector to an A/V amplifier, surround - on both: the room brightness and the par- sion, surrounding us with video. And, sound speakers, a second video source; ticular movie we were watching. best of all, Sharp Vision's bigger and better etc. (The projector's manual, which de= Audi(' and video adjustments, as well as picture is not accompanied by a bigger tails various possible setups, is anottiei- input selection, also can be done using the price tag! We don't think that LCD proj- drastic improvement over the XV -I00.) By top -panel controls on the projector. The ection is ready to take over the home - twisting the zoom lens, the screen size can top -panel controls include one that's trtiss- theater market-yet. But as LCD man- be adjusted.from 25 to 150 inches, depending froto the remote-a focus -pattern dis- ufacturing technology improves-and the ín the last couple _ ing on the amount of space between the play button. Pressing that button causes a dramatic improvements projector and the screen and the size of pattern to be displayed on the screen for of years are likely to continue-SharpVi- your room. Actually, room size isn't quite about 15 seconds, while you make adjust- sion projectors are going to be tough to as critical as it was with previous models, ments using the focus ring around the lens. heat. 13

AmericanRadioHistory.Com A (Pro-) Logical Choice

CARVER HR -895 AUDIO/VIDEO RE- CEIVER. From: Carver Corporation, P.O. Box 1237, Lynwood, WA 98046. Price: 0.:wwr,w..-` ,c--._ $1199.95. g1-9ÓBi We've always maintained that thé true .- heart of a home-theater system is not the video screen. Rather, it's a good audio system that pulls a viewer into the action. We find a small -screen system with big - screen sound far more enjoyable than a big -screen with small -screen sound. The true heart of a home -theater sound system is an A/V receiver, which not only provides the Dolby Pro -Logic sound that's so important, but also serves as a command center for video and audio equipment. CIRCLE 51 ON FREE INFORMATION CARD This month, in our quest for sensible home theater, we tried Carver's HR -895 Dolby Pro Logic Audio/Video Receiver. that it is shown in the display each time the tight time delay, the, out -of-phase right - The HR -895 is Carver's first Pro -Logic station is,tuned. Up to five alphanumeric channel information will arrive at the left receiver. It features a five -channel sur- characters can bestored for each memory. . ear at the same time _the signal from the round -sound amplifier, a "learning type Stations carf be tuned directly by entering right speaker does, and the signals will % remote, and multi -room capability that al- the preset rumber on either the remote -.cancel. With proper !speaker setup- lows a user in a second mom to use the control or the front -panel keypad. It's also n which is very critical for the processing to amplifier to listen to a CD,, for example, possible to scan through the presets, or tó work-we`found that Sonic Holography while the receiver is used in the main room change stations by turfing in theconven- dramatically widened the soundstage of to watch a videodisc. tional manner. = stereo recordings, and produced excellent The front-left and front-right amplifiers A Carver feature cálleu ACCD (for infaging. Sonic Holography is not, of provide power outputs of 110 watts per asymmetrical charge=coupled FM deter- course, intended to ieplace Dólby Pro channel. The center -channel amplifier tor) is provided to reduce multipath distor- Logic. provides 75 watts, and two 35 -watt ampli- tion. ACCD, which is switchable, is said The HR -895 provides rear-panel inputs fiers provide the surround outputs. to be. able to transform á multipath signal =for a laserdisc player and two VCR's. A Seven audio inputs, four composite vid- into a clear signal. by separating the stereo front -panel input is provided, primarily for eo inputs, and three S -video inputs pro- sum and difference sigr-als and rejecting cónnecting_a camcorder. S -video con- vide convenient switching capability. up to 80% of the disto-'tion-filled stereo nectors are provided for he laserdisc input Front -panel audio and video inputs are signal. Tien, "the.15-20% of the signal and VCR1 inputs and Outputs. The second provided for easy accessibility when hook- which is aeán is usedtoaccurately recre- -set_-of VCR connectors provides only coming up a camcorder. ate the rest elf the stereo signal." Because posite -video = jacks. Why, we 'wondered, The tuner section of the HR-895 pro- our suburban location =is not "_typically did Carver provide an S-video_input for a vides a total of thirty FM and AM presets. plagued by multipath_ problems,- we can videodisc player, where it provides little (If you receive FM -band stations over your vouch for ACCD's success only oy noting benefit, and not for a second VCR where cable -TV system, a separate antenna input that the feature seemed to quiet some noise S -video can be very beneficial? Whatever is available for those stations; that input from marginal'signals, «ithout degrading the reason, we should note that the front- and the available stations can also be strong signals. _ = panel inputs do provide for S-video, so stored in presets.) An auto -preset mode Besidess the tuner, the HR 885 offers tape dubbing between S-videó-equipped scans through the selected band and auto- other purely audio- functions; CD playei video recorders is possible, although not matically stores received stations in the inputs and audio tape _inputs and outputs á necessarily cónvenient preset memories. While it's possible to let are provided._ We're thankful that Carvety Two tapé=dubbing options are provided the receiver handle the entire function au- also included a phóno input for connecting on the amplifier. Pressing the TAPE-vCRI tomatically, we preferred to customize the a turntable. Primarily intended for use button lets you dub audio from your audio settings as they were stored. As each re- with those functions, Carver's "Sonic Ho- tape deck to your VCR: (If you,haven't ceived station is tuned, scanning stops for lography" is:also provided. The intent of discovered that your hi-fi VHS VCR can five seconds. During that time, you can set Sonic Holography is to= "restore the 3 ,play the part of a high -quality audio re- the tuning mode (to mono, for example) dimensionality of alive perfórmancé tcorder-with-the distinct advantage of 6 - and set the W bandwidth (to narrow, for through special signal -cancellation and hour taper -do yourself a favor and give it example). If you do not want to store a time -delay cdcuitry." It _attempts- to cor-' a try.) A sedónd, VCRs-VCR2 button lets particular station, pressing the tuning up rect the problems of traditional stereo that, you dub video tapes. Dubbing can be done control causes it to be skipped. occur because your ears ,hear the óutput of- even while you're watching a laserdisc. If you're like us, you might have trouble both stereo speakers. It works by injecting Remember,_ however, that the vcR2 remembering more than a few preset sta- some degree of out -of-phase right -channel connections don't support S -video". You'll tions. The tuner, however, includes a func- information into the left channel' signal= have to use the front -panel camcorder -in- 14 tion.that lets you set the station name so and vice versa. Theoretically, with the put jacks for that; whatever source you

AmericanRadioHistory.Com ake this GIANT Handbook -for-0111.49.95-

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ELECTRONICS ENGINEERS' HANDBOOK, Third Edition Edited by D.G. Fink and D. Christiansen

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ELECTRONICS ENGINEERS' As a member of the BOOK CLUB MI Electronics Engineers' Blue Ridge Summit, PA 17294-0860 Book Club ... - EYES! Please send me Electronics Engineers' Handbook, 3rd Ed. (9255H), billing me $9.95 plus shipping/handling & tax_ Enroll me as a . you'll enjoy receiving Club bulletins every 3-4 the Electronics Engineers' Book Club according to the terms weeks containing exciting offers on the latest member of outlined in this ad. If not satisfied, I may return the book within 10 days off of books in the field at savings of up to 50% and have my membership cancelled. A shipping/handling charge & sales regular publishers' prices. If you want the Main tax will be added to all orders. Selection do nothing and it will be shipped automatically. If you want another book, orno book at all, simply return the reply form to us by Name least the date specified. You'll always have at Address 10 days to decide. Your only obligation is to purchase 3 more books during the next 2 years, City/State after which you may cancel your membership Zip Phone at any time. Publishers' prices shown.' ©1992 EEBC Valid for new members only, subject to acceptance by EEBC. Canada must remit in U.S. funds. and Canada will receive special ordering instructions. PPIF193 Applicants outside the U.S. 15

AmericanRadioHistory.Com choose as the main , signal source is also covered what a difference, the right sdund output to all video and audio outputs (tin - system can make! less one of the Sound amplifier's dubbing buttóns Decisions Sensurround technology was developed is pressed). by' Cerwin-Vega and Universal Studio. It Four surround -sound modes are'of- SENSURROUND HOME -THEATER was first used- in the movie Earthquake, fered. The Dolby mode is the one to use if SPEAKER SYSTEM. From Cerwin-Vega, and with such -success that its developers your source is Dolby encoded. Most re- 555 East Easy Street, Simi Valley, CA were honored with an Academy award. cent movies . you're likely to rent will have 93065; Price: $1660. That same technology is now available a Dolby -encoded soundtrack; with proper e - - for Mine use, in a pre-packaged seVen- speaker placement, the results that can be ' There was a time, not long agcy: when pieceisystem or as separate components. achieved at home will be at least as good as we would base our movie -going decisions The seven -piece system that we tried opt is you're likely to hear inmost movie the- on sound alone. If we thought a film de- intended for use with "big -screen" home- aters It's likely to be better, in fact, be- manded the depth and drama of -Dolby theater setups-those using front- or rear - Cause you can adjust the level and location Surround or THX sound systems, -vie projection TV%. It consists of the HT-CTR of the speakers to perfectly suit your seat- would see thern'in a good theater: Films shielded center -channel speaker, two ing position. whose soundtrack we didn't consider ¿ru- HT-100 shielded subwoofers, and four HT- "Hall"- and "matrix" surround modes cial to our enjoyment would be relegated S6 satellite speakers. For home theaters are also provided for non -Dolby sound to "let's wait until it comes out on video" centered around direct -view televisions, sources. The hall mode adds what we per- status. á - Cerwin-Vega recommends la five-plce ceived as time -delay and echo effects to Using that selection process, we decid- Sensurround setup that includes the sarne give a feeling of spaciousness. The matrix ed to see The Commitments, a film about a four satellite speakers (sold. for $380 a mode, we assume, passively extracts the, group of working-class young Dubliners pair) and one HT-210C "dual subwoofer/ difference between the left and right sig- who form a soul band, at an expensive center -channel System" ($320). That unit nals and feeds it to the rear speaker's. Nei- theater on Manhattan's Upper East Side. integrates two 10-inch subwoofers and ther mode can compete with Dolby Pro We certainly 'didn't get our $7,50's center -channel speakers into a single, Logic (to our ears, they simply distort the rA worth the theater's outdated sound sls- fully-shielded ;cabinet thát 'doubles (or sound), but we can imagine some in- tern didn't do júsíice to the film's wonder- should we say triples?) as a pedestal for the stances where they would prove to be ' ful soundtrack, and since the music made television or monitor. It's also possible to useful. A simulated stereo mode is' pro- the movie, thé whole experience was dis- use the FIT-210C and a paifof HT-S6 satel- vided to create a stereo effect from mon- appointing. lites aionl with a pair of yóur own speak- aural sources. E We finally got ío hear the Commitments ers: a< leing as the center speaker matches The amplifier also offers four center- the way the director intended them -to the left and right ones. (The eXcellent man- channel modes that are switchable. Nor- .sound. No, We didn't shell out another ual' supplied with the speakers explajns mally, Dolby Pro Logic requires a center- $7.50 each, or buy the soundtrack on CD. how to calibrate the system, regardles% of channel speaker 1 so that on -screen sounds We rented the film on laserdisc, and Rs - the configuration.) appear to come from the screen. A "nor- tened to it through Cerwin-Vega's Senstir- 'Now that you've heard alr.the optidps- mal" mode is provided for that'. A "phan- round seven -piece home -theater speaker that are a;railable. we'll get back on track tom" mode creates a center -channel effect system, connected to a Carver Dolby Pro - and tell You about the seven -piece setup using just the left- and right -channel Logic A/V receiver. We quickly di- that we actually: tested. - speakers. A "wide" mode electronically processes the front -channel audio to create a wider soundstage; it's useful if you must place your speakers very close together. The center channel can also be turned off if you.wish. The HR -895 features a clock that can display time in either the 12-. or 24 -hour format. The clock provides sleep -timer and program -timer capability as well. We think that a program timer is very important in an audio system. (Some of us record more programming from the radio than from television.) While we're happy to see Carver provide a program timer, which many manufacturers ignore,. we're not satisfied with the single -event capability. Our experience with the Carver HR-895 makes us think that it could be a sensible source of terrific home -theater sound. Its multi -room capability will keep the video watchers and audiophiles on speaking terms-or let you keep track of what's happening on the screen when you can't be there to see if. But, the funny thing is, we didn't find ourselves leaving the room very often when the 'HR -895 was doing its CIRCLE 52 ON FREE 16 thing. INFORMATION CARD

AmericanRadioHistory.Com Our first reaction upon seeing the six given sound was emanating. In other large boxes in which the system was words, we quickly forgot that we .were Video Viewing in packed! was that we'd be spending aq en- listening to three front speakers-and tire day simply unpacking and wiring the seven speakers altogether. We were spend- the' 90's system. In reality, the process wasn't that ing too much time enjoying the movie. bad-and our pre -production Sensurround For the truly realistic sound reproduc- arrived two weeks before the manual did! tion that we experienced, it's crucial that CD/CDV/LD COMBINATION DISC The HT-S6 left, right. and surround the system is wired, arranged. and cali- PLAYER MODEL XR-W70A; from speakers feature a 61/2 -inch midrange'and brated properly. Luckily, the manúal that Toshiba ,America Consumer Prodúcts, Totowa Road, Wayne, NI 07470; 1 -inch polycarbonate dome tweeter. (Our accompanies the speakers goes beyond the Inc., 82 pre -production models were not shielded). call of duty, explaining not just how to set Price: $599. The direct -radiating speakers are housed up the system, but providing a thorough in bass -reflex (vented) enclosures that 'tutorial in home -theater concepts that re- When videodisc players were first intro- the measure 1134 x 81/2 x 11 inches. Their fre- veals why each piece must be placed just duced back in the 1970's, format quency response is rated at 80 Hz-20 kHz, so. Detailed, drawings depict proper wir- bombed. Video cassette recorders, on the ± 2dB. ing for each configuration. The manual other hand, caught on like wildfire. Con- The HT-CTR center -channel speaker also provides the consumer with advice on sidering that most people's, home -video a - features two 61/2 -inch midrange drivers improving room acoustics and incorporat- setups at the time consisted ,of small screen 'color TV, it's not surprising that and a 1 -inch polycarbonate dome tweeter. ing existing speakers into the system-all The speaker system is also housed in a in plain English. more folks weren't leaping at the chance to bass -reflex enclosure, but not in a standard Since we've had the Sensurround sys- buy the more -expensive videodisc players, rectangular box. Instead, the enclosure is a tem in our living room, we've changed our despite their superior picture and audio trapezoid that measures about movie -selection process. Now we prefer to quality. After all, the VCR offered con- 16% x 83/4 x 113/4 inches. The tweeter and watch even the epics. adventures, and mu- sumers ,the ability to record television port are located between, and slightly for- sic films on videotape or laserdisc in the show's as well as to watch prerecorded ward of, the midrange drivers. The mid- comfort of home-where we can real- movies-and the selection of films on vid- range 'drivers are angled out from the istically expect our sound 'system -to he eocassette was far greater than those avail- center. The idea is to eliminate an on -axis significantly better than those'we found in able on disc. After a few years of sluggish hot spot for smoother, more realistic sound most local theaters. sales, Philips, the inventor of the LaserVi- that corresponds better to the on -screen sion, pulled their videodisc players off the action. The frequency response of the HT- market, and so did most other videodisc CTR is rated at 80 Hz-20 kHz. ± 2dB. HOME:THEATER manufacturers. The HT-110 subwoofers are what really (Continued from page.12,) The LaserVision format, however, was make Sensurround work. They consist of a the only videodisc format that was never it has 10 -inch driver mounted in a bass -reflex 46 -inch GE ri ar-projectioít TV on sale for totally abandoned. Now, ín the 90's, way, enclosure that measures 171/2 x 13 x 241/2 just $1500, a center -channel speaker from finally come into its own. In a the inches. The HT-110 can handle inputs up Kenwood for $129. a Fisher A/V receiver -very success of the VCR, which pushed to 250 watts. Although not on our pre- with Dolby Pro -Logic for $300, a Pan- the videodisc player out of the market in production models, the HT-1l0 offers a asonic four -head hi-fi stereo VCR for the 70's, helped pave the way toward its defeatable passive crossover. If you were $330, and a Pioneer laserdisc player for increasing acceptance today. There's no we to use a single amplifier to drive the speak- $400. That's $2.329, and you'd just need question that the VCR changed the way ers, you would feed the left, right, and to add speakers and perhaps a subwoofer used our television sets. After all, with all center -channel amplifier outputs to the to create a full-fledged home theater. A those movies being watched at home, the .subw000fer, and then feed the left, right, Sony rack system caught our eye also- next lógical step was for consumers try to and center speakers from the subwoofer's sale priced at $1299, it included a tuner, a duplicate the movie -theater experience wiring panel. The crossover switch would 5 -disc CD changer, a 5 -cassette changer. ' using their home video and audio equip- be in; or ona, for this setup. an A/V amplifier with Dolby Pro=Logic, ment. Manufacturers .were quick to re- We didn't get to try that wiring scheme, and center -channel, right, left, and two spond to (and inflame) that desire, intro- but instead used the line -level subwoofer surround speakers. The same system with ducing stereo TV's, increasingly large - output of our Carver A/V receiver, along -a dual cassette deck cost $999. Either sys- screen direct -view sets, rear- and front- with a separate amplifier, to drive the sub - tem would look nice next to an "existing ' projection systems, surround -sound pro- woofers. The results were outstanding. If large -screen TV, and their racks even had cessors, A/V receivers, and speakers in- you enjoy explosions in your home theater, two shelves conveniently' available to ac- tended for use with audio and video of the sort so plentiful in Terminatór 11, commodate a laserdisc player and a VCR. equipment. then you won't be able to get enough of the The scouting around that we did took As consumers became more ac- HT-110's. Explosions, we must admit, about the time we might have spent watch- customed to sophisticated home -theater aren't our thing. Even so,'the subwoofers ing a movie. If we were actvally about to systems, a new niche was created for the added tremendous enjoyment to the movie buy a home -theater system, we'd be will- laserdisc player. After all, once you've watching experience. Trucks sounded like ing to spend quite:a hit more time than spent hundreds or thousands of dollars on real trucks. Unexpected thumps could that. We, would have auditioned the sys- AN equipme>Gtt,'you're going to want the make us jump. tems to get a better feel for their ca- best possible source material. With good Once the setup was complete; we were pabilities, and we would have pressed the equipment, the flaws in VCR performance ready to give The 'Commitments a second sales personnel with questions-or de- become obvious. That's why many serious chance. We were impressed with the ac- manded to seé the operating, manuals to A/V enthusiasts now consider the laser- curacy of the positioning of the sound. make sure that each component offered the disc player to be an essential ingredient in Even more impressive, the balance of the functions we required. Because in home - any home -theater installation=more im- sound was so even that we could not pick theater installations, good planning will portant, even, than a VCR. The difference players out, the particular speaker from 'which, a definitely pay off. in quality is dramatic: Laserdisc 17

AmericanRadioHistory.Com TEST RESULTS -TOSHIBA XR-W70A LASERDISC PLAYER

The video frequency response of a laserdisc player is a measurement of how accurately it can reproduce signals of different frequencies. It is measured by playing a special signal from a test TEST RESULTS -VIDEO SECTION disc that contains bursts of several specific frequencies and observing the out- Frequency Response put on a waveform monitor. The (@0.5 MHz) laboratory -measured frequency re- 0 dB (@2.0 MHz) 0.78 sponse of the Toshiba XR-W70A was - dB (@3.58 MHz) -2.92 dB not what we had expected from our (@4.2 MHz) 3.84 dB subjective evaluations. At 4.2 MHz, the - response was down 3.84 dB. That's a bit Signal -to -Noise Ratio worse than we've seen from other, sim- Red Field ilar players. Chroma AM 44.8 The signal-to-noise ratio is a mea- dB PM 36.5 dB surement of the amount of unwanted Luminance noise on a fixed, flat -field video signal. 100 IRE 45.1 dB A red field, used in our lab tests, is usually preferred to measure the chroma TEST RESULTS -ANALOG AUDIO signal-to-noise ratio. AM chroma mea- SECTION surements indicate the strength of the Output Level color signal, while PM chroma indicate (1 kHz) 1.53 volts (CX on), volts the purity of the color signal. The AM 0.52 (CX off) chroma signal-to-noise ratio was mea- THD sured at 44.8 dB, the PM signal-to-noise (@75% modulation) 0.76% ratio was measured at 36.5 dB, both (CX on), 0.59% (CX off) adequate, but not outstanding. Signal/Noise Ratio The luminance signal-to-noise mea- 86.4 dB (CX on), 64.1 dB (CX off) surements indicate the brightness and detail that you can expect to see in re- TEST RESULTS -DIGITAL AUDIO SECTION corded videos. Such measurements in- Level dicate the amount of snow that you're Output likely to see in the picture. Depending (1 kHz) 2.17 volts Signal/Noise on the reference luminance level used when making the measurement, the (De -emphasis in) 110.0 dB luma signal-to-noise ratio was mea- (De -emphasis out) 110.0 dB sured at 45.1 dB, which is what we Channel Separation would expect. Using the S -video output left 121.0 improved the luminance signal-to-noise dB right 126.9 dB ratio by about 1.5 dB. The audio section of the XR-W70A THD @0 dB yielded better than average perfor- 20 Hz 0.0031 mance, as indicate by the tabulated re: 1 kHz sults. 0.0028 10 kHz 0.0045 In summary, the lab results seemed to be a bit of a mixed bag.. But the results Linearity Error are the same as with our subjective (0 dB to - 50 dB) -0.01 dB tests. The XR-W70A is not something that an audio/videophile is going rush to Frequency Response out and buy. But its deficiencies are (20 Hz to 20 kHz) +0, -0.12 small enough that a double-blind viewing test between the XR-W70A and ADDITIONAL some more expensive players would DATA end in a draw. Weight 19 pounds Dimension (H x W x D) 51x 181/2x17/inches 6AAT,A, Power Requirement 31.5 Watts Y{% Random -Access time 2.0 seconds Time 1 ea ,. -;----`ttis Scan (Side to Side 2) 5.5 seconds 8 , . . . Notable Features Flying head, 4n erase Digital noise reduction, »M% Timebase corrector, Bidirectional frame advance, Slow motion play 1/sX and 1/1oX), Auto indexing, Real-time counter with ails - --wn memory, 1-month/6-month program timer, i ! Front -panel A/V jacks, Control -L editing n.ux interface, Control -S input. %.

Testing revealed a larger than expected drop-off at higher frequencies.

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MAIL-ORDER LASERDISCS

As laserdisc players have grown in popularity, the selection of movies and music videos available on disc has kept pace. Unfortunately for LD converts who don't live in big cities on the East TosHiati and West Coasts, stores that sell laserdiscs are still few and far between, and those that offer a decent selection of LD's available as overnight rentals are even more scarce. Some entrepreneurs have seen op- t1 o P-!5" portunity in that situation, and mail- order laserdisc shops are now flourish- ing. There are.big companies, such as Columbia House Laserdisc Club .4+_;, (800-538-2233). Discount clubs in- F clude Ken Crane's in Westminster, CA (800-624--3978 or 800-626-1768 in CA); the LaserDisc Fan Club of Long Beach, CA (800-322-2285); Laser Craze in Boston (617-338-9820), Sight and

- : Sound in Waltham, MA (617-894-8633); CARD - CLRCLE 53 ON FREE INFORMATION and Brooklyn -based SEM Video Prod- ucts (800-247-6644 or 718-645-1663). Used laserdiscs are available from such companies as Video Brokers in Wash- display tyvice the horizontal resolution I onds every laserdisc chaptero CD track 7 ington DC (202-328-0428) and Triton (more than 420 lines) of VHS VCR's, and so you can find what you're looking for. (It Video in New York City (212-243-3610). have the added advantage, of providing Will automatically change to the second CD -quality sound. side of °3 laserdisc.) Yon can program the During those years when_ the laserdisc unit tá play tip to 24 chapters or tracks In was floundering, the audio compact disc - any desired order; again, you can switch ninl; the lbw -scan mode steps scanning up about 10 x and high -scan steps - (which was introduced a couple of years pack and forth between laserdisc sides. to normal; =after the LD), was making a big name for xOf course, there aren't, too natty laser- it up to 30 x normal. The scanning was itself. Consumers who have become famil- discs that we, would like to..wat'ch in ra t- serviceable on CLV (constant linear ve, iar with the sound quality and convenience dom order.) A random mode leis you play locity or extended-play) discs, but, of to that for features of -the CD format now are quite - all songs on a CD in rtitdozn &der; on a course, couldn't compare CO willing to consider a similar format for laserdisc with a table of contents (such as a (constant angular velocity) discs. :video. Laserdisc players, like standard CD CD video laserdisc), you can play the A soft -picture function can filter some players, offer quick access to "tracks"- chapters on one side of the disc in random backgrouind noise from old vintage many videodiscs are arranged in sections order- movies. We also found it useful to soften when we were to make! it easy to "fast forward" to a _ Another handy feature is automatically the image sitting too close specific scene in a movie; or song oii a called into play if you turn the power to a largcscreen. concert video. And now that the price of switch 9ff during playback=of s laserdisc: The XR-W70A was a strong performer laserdisc players has dropped and virtually - when you turn the player back on, it will that doesé't offer any surprises. It didn't - ` all laserdisc players also play CD's, an LD/ - pick tip when; it left off_ For dubbing CD's wow us with all kinds of high-tech, high

- CD player represents an economical. - onto cassette tape, a peak -search function end features, but ircertainly did a respec- table doing what it was supposed to. If - choice of an A/V component. Imake7s=it r bre&ze to set you[ recording job a who's been watching . In our home -theater setup, we used a level: it will find the peak level; and output you're videophile combination disc player from Toshiba. 'it for about eight seconds so you can práp- lasérdiscs since the late 1970's, then look The Model XR-W70A CD/CDVILD Player erly set your recorder. elsewhere for your next player. But if can play 3- and 5 -inch CD's, 5 -inch When you insert a disc into the ?É R you're still wondering what all the laser - CDV's (CD with Video discs), CDV t W70A, whether it's a CD, a'-CDV, or a disc fuss, is about, why not find out by gles, 8- arid 12 -inch CD Video LD's, and lasetslfsc, the player will autotratically de- giving the XR-W70A a try? 8- and 12 -inch laserdiscs.= It also adds a tect what kind of disc it. is-just as any couple bf convenience features to hom e - other combi player willdo.-A special func- movie viewing. tion "Direct CD," tells the player that you The most important convenience !fea- are gong to be playing a CD. That not only ture is two-sided play. It's not necessary tó speeds its decision -making process, bat it manually flip the discs from side 1 to side 2 turns bff the video -circuitry, `o eliminate because the player automatically positions the possibility of interference with the. tt- the pick-up carriage assembly from one - side of a disc to another. That solves the An optical digital 'output terminal is

- only complaint we had with videodisc provided for direct'connection to ampli- players'. (Now, if we could only get°disc fiers 2nd other equiprpentwith digital; in- manufacturers to end side 1 at some place puts. - other than the middle of a scene... .) Both the remote cántrol-and the front "Actually, it's made here-the manual just - Intro Scan is another convenience fea- _ ` pangl offer a rotary three-speed scan con reads like it was made in Japan." nine that lets you play the first eight sec- 1= troll The clear-scan mode gives slow scan- 19

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AmericanRadioHistory.Com

For more information on any product ion, EL E TRON/CS; :-I NI SH L /S T ate numberis onon the Free Information Card. ,

SuperFlat Rear-Projection TV Incorporating much of the technology used in their SuperFlat direct -view TV's, Panansonic Company's (One Panasonic Way, Secaucus, NJ 07094) PTP SIXF20 also features a new screen and lens system developed for rear-projection sets. The 51 -inch set is capable of more -than 700_ lines of horizontal resolution, and can deliver more than 300 foot -lamberts of brightness for a clear picture even in brightly lit rooms. The TV's audio specs include 20 -watts -per-channel output (8 ohms, 60Hz-15kHz, 1% THD), MTS stereo with dbx noise reduction, and Dolby Surround Sound. Other features include picture -in -picture, Artificial Intelligence Control of image quality to maintain the proper contrast level, parental guidance control, built-in clock and sleep timers, dual on/off timers, favorite -channel and favorite -picture memories, and a remote that's capable of controlling most VCR's and cable boxes and all Panasonic laserdisc'players. The set is just 27 -inches deep, allowing it 'to fit through standard doorways. Price: $2999.95. CIRCLE 54 ON FREE INFORMATION CARD

Small Speakers for Big Sound If you believe that speakers should be heard but not seen, setting up a home theater can be a real challenge. Bose (The Mountain, Panasonic Projection TV Corporation Framingham, MA 01701-9168) presents an easy solution in the unobtrusive form of their Acoustimass-7 Home -Theater Speaker System . The matched, front-channel speaker system includes three dual -cube arrays (center, front, and right channels)

. and a bass module. The magnetically shielded front -channel speakers, which measure just 63/4 X 31/s x 43/4 inches, include hardware that allows several mounting options-wall and ceiling brackets, table stands, and floor stands. Each array includes a pair of 21/2 -inch wide -range drivers. Using a matched center speaker ensures that sound remains balanced and consistent from channel to channel. The bass module, which is small enough to be hidden anywhere in the room, launches sound waves from a pair of high-performance 53/4 -inch low-frequency drivers into the room in the form of moving air masses- All connections are made through the bass module, and built-in protection circuitry guards the system components against excessive input levels. Price: $899. CIRCLE 55 ON FREE INFORMATION CARD

Instant Home Theater Bose Home -Theater Speaker System Intended to provide better sound without complex hookups, the HTS-100 instant home -theater component from Mitsubishi Electronics America, Inc. (5665 Plaza Drive, Cypress, CA 90630) delivers Dolby Pro Logic Surround Sound as a function of normal television operation. Installation requires only one - step and does not disrupt the normal connections between the TV and VCR or laserdisc player. Price: $599. CIRCLE 56 ON FREE INFORMATION CARD

Video by Zenith, Sound by Bose Bose Acoustimass speaker technology is also available built into several models of Zenith (1000 Milwaukee Avenue, l Glenview, IL 6(025) television sets, creating ,... - all -in -one home theaters featuring "Bose VideoStage Surround System." It might not 'be Dolby Pro -Logic, but for those interested in surround -sound without the fuss, the combination of front -channel speakers built Into the TV, and two separate rear speakers works well. The Model AB5285BG is a 52 -inch rear-projection set that features black level expansion, which expands the number of gray-to -black shades that can be displayed, leading to greater depth and richer colors. White compression reduces glare from bright white areas, for crisper edges of bright images. Lumina noise reduction decreases the "noise" that often occurs when sharpness levels are increased, and edge enhancement circuitry eliminates fuzzy edges in individual scenes. Price: $3295. Zenith/Bose Surround -Sound System CIRCLE 57 ON FREE INFORMATION CARD

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You get that big free lodging for six days and five nights at your Name choice of Hawaii, Mexico, Las Vegas or the Bahamas. Address You're going to be very impressed with the book selections ZIP as well. These are not all paperbacks, but the same, high -qual- Cdv State Date ity volumes you see in bookstores at many limes your own pur- Credit Card No. Esp. just room on this page chase price. Frankly, there isn't enough Signature

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AmericanRadioHistory.Com Heath zen-lh

HEATH/REFLEX WIRELESS DOORBELL CIRCLE 119 ON FREE INFORMATION CARD

A quick and easy way to add or replace a doorbell

Most of you are probably fa- The transmitter will look attractive approximate installation point, we miliar with the Heath Com- mounted at any doorway, and the re- learned the value of something men- pany-or at least "Heath ceiver looks much like a traditional tioned in the' installation manual: kits." While Heath is no longer in the kit doorbell chime box-both units are "Don't mount the receiver or transmit- market, they have launched what an off-white color. ter directly on a metal surface, as the they call the Reflex line of home elec- The receiver unit offers three switch - range will be drastically reduced." If tronics. That line of products is de- selectable sound options. There's a you must locate either the receiver or signed to allow the home do-it- traditional "ding dong" setting, a transmitter on a metal surface, it's sug- yourselfer to install automated light- "ding ding" setting, and. a single gested that you mount it on a piece of ing, wireless light switches, auto -shut- "ding" setting. Besides serving the pur- wood at least 1/4 -inch thick. off lighting, or a wireless doorbell. All at pose of user preference, the tnree Our doorbell has been installed for very affordable prices. This report will sound options allow you to have a a couple of weeks now and is still focus on their SL -6153 wireless door- different sounding bell at each of up working perfectly. That shouldn't bell. to three doors. That's the main reason sound impressive to you-after all, why the wireless doorbell is available Iwo weeks isn't all that much time- The Device. The SL -6153 is a pre -built in three different RF frequencies. It is but it is at the very least gratifying to unit that allows you to install a door- also useful in case your next-door this reviewer who had something to bell anywhere without having to hook neighbor has the same unit. compare this new doorbell to; a wire- up any wires at all. Apart from the The most obvious need for a wireless doorbell from another manufac- "doorbell button transmitter" and a less doorbell is in cases where no turer. The receiver of this "other" "doorbell bell receiver," a few mount- doorbell exists at all. The user is then wireless doorbell used only two "AA" ing screws or some double -sided able to quickly install an "instant" cells for power, which lasted only a tape (both of which are included) are doorbell. You may even want a wire- couple of days. Also, the chime on the all you need to do the installation, The less doorbell for your bedroom door. Heath doorbell is much louder and $29.97 doorbell system has a max- Many homes will have a doorbell at realistic sounding than that other one. imum range of 50 feet and works for a the front door only, in which case a Even though that other doorbell cost year on one set of batteries. That wireless bell could come in handy for ten dollars less than the Heath unit, it range should provide plenty of suit- the side or back door. was certainly no bargain. able locations to place the receiver. If the Heath/Reflex SL -6153 wireless The transmitter, or button, is roughly installation. When we first tested our doorbell sounds like something you the same size as a match box, and it's wireless doorbell-with one person could use, or if you're interested in any powered from a small 12 -volt battery, holding the bell and another holding of the other Reflex products, contact which is included with the unit. The the button-it did indeed have a Heath (PO Box 1288, Benton Harbor, Ml receiver, or bell, is powered from three range of at least 50 feet. However, 49023-1288) directly or circle No. 119 22 "D" cells, which are not included. when testing out the doorbell at its on the Free Information Card.

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AmericanRadioHistory.Com PRODUCT TEST REPORTS

By Len Feldman More and more cam- problems, offering 2 hours at the beginning of a scene corder enthusiasts are of recording time (and, or at any time you choose. these days turning to the more recently, 21/2 hours on More advanced features 8mm format. For reasons somewhat thinner tape). include "edit erase," a sys- that remain something of a Canon has been a major tem for erasing up to a mystery, American video proponent of the 8mm for- minute's worth of unsatisfac- enthusiasts initially thought mat almost since it was tory recording and Canon UC1 that "bigger is better" and standardized. That inno- returning to the starting opted for heavy, bulky, full- vative company now offers point of a scene that is to 8mm size VHS camcorders. Light- three camcorders in their be re-recorded; backlight- er and smaller compact "UC" series. Of those, the ing compensation, which Camcorder VHS units, dubbed VHS -C, UC1, which was tested for Can be used when exces- made some inroads when this report, is the least ex- sive background lighting pensive, with a suggested occurs behind the subject list price of $1499.00. being taped; fade-in and Billed as the world's light- fade-out; and self -timer re- est 8mm camcorder (at cording, a ten -second 1.28 pounds without tape, standby mode that allows wireless controller, and bat- you to get into the picture. tery), the UC1 features an Finally, if you are using a 8 x internal -focus zoom partially recorded tape, a lens and six -layer ceramic blank=tape search function circuit assemblies. A de- allows you to locate the tachable, full -function, end of the recorded sec- wireless remote control; an tion; that avoids having ¡ w pv: ó on . 0 -screen menu system; long blank, unrecorded ii i and a 2-page title superim- sections on the tape. yy - VV poser with "shadow" letters si and battery backup (for re- CONTROLS taining titles) are a few of its As viewed from. the rear, many features. The titles are the left -side surface of the displayed in frames using unit houses power -focusing an interlace method that buttons; an automatic- A prevents the broken diago- focus on/off button; the nal lines that are usually fade, backlight compensa- apparent in other camcor- tion, and date buttons; and ders that use a field - buttons associated with ti- CIRCLE 120 ON FREE INFORMATION CARD memory method. tling. Toward the rear of that Other features include a surface, near the electronic The Canon UCI compact 8mm camcorder. 7 -mode high-speed shutter, viewfinder, are a counter - a "gain -up" switch for low- reset button, a menu/play level (2 -lux) light sensitivity, a button, fast- forward/record introduced. But since re- 24 -zone evaluated white - search and rewind/record cording.time was limited to balance system, automatic search buttons, a select/ a maximum of 20 minutes, wind screen, and a variety record review/stop button, and later extended to 30 of power -supply options (in- and an edit switch. The minutes, their success was cluding alkaline batteries). function of the buttons that limited. The introduction of As is true of many 8mm- have more than one pur- the 8mm format solved camcorder models, you pose depends on whether both the size and weight can set time and date so you are in the record or 26 and the recording -time that they may be displayed play mode.

AmericanRadioHistory.Com Earn Your B.S. Degree The right side panel of playback recordings on a in the camcorder body N set equipped with audio/ (again, viewed from the video inputs or to use the ELECTRONICS rear) houses the power on/ camcorder to record from or off switch, a power -zoom another source, such as a rocker switch, the start/stop VCR. A battery pack or an COMPUTERS (record) switch, and a AC power adaptor (sup- mode select switch that plied) attaches easily to the chooses camera or play- rear of the camcorder. back modes. A detachable á' wireless controller can be swung up (or detached) to TEST RESULTS a uncover tape return, re- Advanced Product Eval- wind, play, fast forward, uation Labs (APEL) start/stop, zoom, stop, rec- measured the performance ord, still -frame, and counter of this camcorder. Using the reset buttons. With the wire- "gain up" function, mini- less controller swung out of mum illumination required the way and with the hand - to produce a full -amplitude grip section swung down, video signal was 1.9 lux, By Studying at Home access is gained to the which was slightly better Grantham College of Engineering, than the 2.0 -lux level eject switch that is used to now in our 42nd year, is highly ex- claimed by Canon. White open the cassette com- perienced in "distance education"- balance, or the amount of partment for loading and teaching by correspondence-through that unloading of a cassette. As chrominance (color) printed materials, computer materials, appears on a neutral ob- long as a battery or power fax, and phone. is ject when the white - adaptor connected to No commuting to class. Study at balance control is set for the camcorder, the eject your own pace, while continuing on button will work even when optimum was 12 IRE, which your present job. Learn from easy -to - power is off. was a bit poorer than we understand but complete and thorough The audio and video in- would have expected. lesson materials, with additional help put/output terminals are While color contamination from our instructors. located up front, below the (color bursts appearing on Our Computer B.S. Degree Pro- camcorder's lens and built- a fine black and white pat- gram includes courses in BASIC, in microphone. Those termi- tern) measured 8 IRE when PASCAL and C languages as well as nals can be used to measured from the camera - Assembly Language, MS DOS, CADD, Robotics, and much more. Our Electronics B.S. Degree Pro- TEST RESULTS-CANON UC1 8mm CAMCORDER gram includes courses in Solid -State Analysis and Design, Control Specifications . Mfr's Claim PE Measured Circuit Systems, Analog/ Digital Communica- Minimum illumination 2.0 lux 1.9 lux tions, Microwave Engr, and much more. White balance N/A 12 IRE An important part of being pre- Color contamination N/A 8 IRE* Horizontal resolution pared to move up is holding the right Camera N/A 330 lines college degree, and the absolutely neces- Record/play cycles N/A 240 lines sary part is knowing your field. Video signal-to-noise ratio Grantham can help you both ways- Camera Chroma AM N/A 43.9 dB to learn more and to earn your degree Luminance N/A 39.5 dB in the process. Record/play video out Write or phone for our free Chroma AM N/A 40.1 dB catalog. Toll free, 1-800-955-2527, or Luminance N/A 40.3 dB Lens f/1.8, 8 x zoom Confirmed see mailing address below. Minimum focal distance 36 inches 35 inches Microphone max. output N/A -0.41 volts Accredited by Ext. microphone sensitivity N/A 3.1 mV the Accrediting Commission of the Audio signal-to-noise ratio N/A 58.3 dB National Home Study Council Power requirements 4.9 watts 6.5 watts Weight 1.28 lbs. 2.0 lbs.* Dimensions (H x W x D, inches) 5Yºx31/8x6% Confirmed Suggested list price $1499.00 GRANTHAM *See text College of Engineering Grantham College Road 27 Slidell, LA 70460

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Build an Aviation =Bund Receiver

Join a growing throng of listening enthusiasts who regularly tune in commercial air-to -ground and ground -to -air aeronautic communications.

BY FRED BLECHMAN

If, like many scanner enthusiasts consisting of L1 -L5 and C2 -C6. Sig- That signal is used to automatically and ham operators, you are inter- nals in the 118 -135 -MHz VHF (very high decrease the gain of U2 when strong ested in listening in on all the ex- frequency) range are coupled signals are present or tc automatically citement manifest in aeronautic through C7 to a VHF transistor (Q1), increase U2's gain for weak signals. communication, but lack the equip- where the signals are amplified. From That keeps the output volume of the ment to pursue your interest, then per- there, the signals are fed through C8 circuit within a comfortable listening haps the Aviation Receiver described to the input of U1 (the NE602 dcuble- range regardless of the strength of the in this article is for you. The Aviation balanced mixer), which in this ap- incoming signals. Receiver, designed to tune the plication serves as a local oscillator. A The receiver circuit also contains a 118-135 -MHz band, features excep- variable inductor (L6) and its associ- squelch circuit that is controlled by tional sensitivity, image rejection, sig- ated capacitor network set the local - potentiometer R3, which is used to kill nal-to-noise ratio, and stability. The oscillator frequency at 10.7 -MHz high- random noise below a selected receiver is ideally suited to listening in er than the incoming 118 -135-MHz threshold level. When properly set, the on ground and air communications signals. A tuning network, consisting of squelch control virtually eliminates associated with commercial airlines varactor diode D1 and potentiometer background noise, so that all you hear and general aviation. R1, allows the local -oscillator frequen- are incoming signals that can be Powered from a 9 -volt transistor -ra- cy to be tuned across about 15 MHz. brought up to a usable level. Potenti- dio battery, it can be taken along with The 10.7 -MHz difference between ometer R2 controls the overall volume you to local airports so that you won't the received signal and the local -os- fed through C26 to U4, an LM386 low - miss a moment of the action. And cillator frequency (i.e., the intermedi- voltage audio -power amplifier. Due even if you're nowhere near an air- ate frequency or IF) is output at pin 4 to the overall design and squelch port, this little receiver will pick-up the of U1 to a 10.7 -MHz ceramic filter (FIL1). control, the audio output is quite low air -to -ground and ground-to -air com- The filter is used to ensure a narrow in background noise, and yet it's ca- munications of any plane or ground pass band and sharp signal selec- pable of driving simple communica- facility within about 100 miles! tivity. tions speakers or earphones to The output of FIL1 is amplified by Q2 excellent volume levels.

Circuit Description. Figure 1 shows and then fed through 016 to U2 (an a schematic diagram of the Aviation MC1350 IF amplifier), which, as con- Construction. The Aviation Receiver Receiver-a superhetrodyned AM figured, also offers automatic gain was assembled on a printed -circuit (amplitude modulated) unit built control (AGC), as we'll see shortly. The board, measuring about 4 x 43/4 around four IC's: an NE602 double - amplified 10.7 -MHz IF signal is peaked inches. Figure 2 shows a full-size tem- balanced mixer (U1), an MC1350 lin- using variable transformer T1. The AM plate of that printed -circuit board's ear IF amplifier (U2), an LM324 quad audio is then demodulated by diode layout. A kit of parts (which includes op -amp (U3), and an LM386 audio D2. After that, the audio is fed in se- an etched and pre -drilled, printed - amplifier (U4). quence through the four sections of circuit board, but no case) is offered In operation, an antenna that plugs U3 (an LM324 quad op -amp). by the supplier listed in the Parts List. into J1 picks up the AM signal. That Note that a portion of U3-a's output Although most of the parts for this signal is then coupled through C1 to a signal is fed back through resistor R25 project are commonly available three -section, tuned -filter network, to the AGC-control input of U2 at pin 5. through conventional electronic- 31

AmericanRadioHistory.Com R28 S1+ C10 R7 R11 { C16 C31 C18 1K 1K 27012 220 R5 10 S .001 10 61 1K . . _L/1+ IE_ +I( 9V R4 CB FIL1 R10 47K .001 B 10.7MHz 1MEG IE C17 = 1 .01 D1 R6 Ut:: 02 3 r 2SC2570 27052 NEA02 2N3904 D2 1N270 3 6 7 C7 C6 C9 R8 I .001 + 10K 82pF .01 C19..r I E+44V1r- .01 C13 T T1 --E- C11 n01 10.7MHz N _ 10 C12 k00/-- R12 27pF L5 -)1-* 10K L4 2T -IH C20 1.44 .33µH .01 R25 C4 1K 82pF -000 L6 +9V C5 1E C23 -)I--- 3.9pF C14 1µH = C30 1 .00,-27pF C24 .01 .1 C3 R1 L3 R16 R17 3.9pF 10K 2T D1 47K 10K g TUNING R22 BB405 47K L2 C2 33K A DR 1_ .33µH 82pF +9V - + 9V BB505 R21 IE )I 47K ll Cl 00r C15 R19 R18 .001 10 10 100K 1/4 LM324 1/4 LM324 L1 1K R15 + 9V ji 2T 47K 7

ANTENNA 1/4 LM324 1 C26 1/4 LM324 D3 10 1N914 C22 i + 9V .47 R23 I J2 R14 C29 10K SPEAKER R20 1MEG I 220 47K R27 = C28 vti 1K .01 R24 R3 1_ R2 47K 10K 10K C25 R13 SQUELCH VOLUME 10 33K +IE 1M

Fig. 1. The Aviation Receiver-a superheterodyne unit, built around four IC's-is designed to receive AM signals in the 118 -135 -MHz frequency range.

plan to use what you have on hand, At the frequencies involved, the 1;.' keep in mind that the circuit -board placement of every wire and part, a layout was designed to accommo- and every part value is critical for trou- , date components of specific dimen- ble -free performance. sions in some cases; jacks J1 and J2, Once you've obtained all of the kO4 Y . ! ^ switch S1, transformer T1, and all three components and the board for the Si,l/i , . .e ó ::: 01 fl potentiometers, for example. To ease Aviation Receiver, construction can O 1' .,,, the pain of obtaining those parts, a begin. A parts -placement diagram is "Special Parts Kit" is also available shown in Fig. 3. When assembling the from the listed source. project, take special care that polar- Also note that either of the Siemens ity -sensitive components (electrolytic All of the components for the Aviation parts specified in the Parts List for capacitors, diodes, and transistors) Receiver (including the 9 -volt transistor - varactor diode D1 will work, but both are installed properly. Just one part radio battery that powers the circuit) may be difficult to find from hobbyist installed backwards can cause griev- mount on a single printed-circuit board. sources. However, the second unit ous harm! (BB505) is available from Allied Elec- Begin by installing the passive com- components suppliers, a source for tronics. ponents (jumper wires, resistors, ca- some of the more difficult to find parts However you go about collecting pacitors, and inductors). Follow that is given in the Parts List for those who the parts for this project, don't even by installing the active components; prefer to do their own shopping. If you think about building the receiver cir- diodes, transistors, and IC's. Once the 32 opt to gather your own parts or you cuit without the printed -circuit board. active components have been in-

AmericanRadioHistory.Com consider the enclosure that will house 4,9 your receiver. ?.. The receiver's circuit board can be ,0 housed in any enclosure that you O O choose. However, if you prefer, an optional case and knob kit for the re- 1 1.* :* ceiver is available from the supplier listed in the Parts List. The optional case is supplied with neatly lettered front and rear panels, knobs, rubber feet, and mounting screws. If you choose a case, other than the one available from the listed supplier, it will be necessary to drill holes in the front and rear panels of theenclosure to accommodate the controls (S1, R1, R2, R3) and the jacks Wand J2). Once drilled, the front and rear panels of the enclosure can be labeled using dry - transfer lettering. The antenna for the Aviation Re- ceiver can be as simple as a 21 -inch length of wire, or you can get a fancy roof -mounted aviation antenna, If you are near an airport, you'll get plenty of on -the -air action from the wire antenna, but if you're more than a few miles away, a decent roof - mount antenna offers a big improvement.

Alignment and Adjustment. 4 INCHES ie Aligning the Aviation Receiver consists Fig. 2. Here's a full-size printed -circuit pattern for the Aviation Receiver. The printed- of nothing more than adjusting the circuit board can be purchased as part of a full-blown kit or separately from the slug in the local -oscillator coil (L6) for supplier listed in the Parts List. the center of the desired tuning range, and peaking the IF transformer (T1). The receiver can be calabrated using a VHF RF signal generator, frequency counter, or another VHF receiver by setting R1 to its mid -position; remember that you want to set the local -oscillator frequency ?0.7 -MHz ,=_r higher than the desired signal or 'r, ?if' range to be received. Then, using a non-metallic alignment tool-a met- 4 al tool of any kind will drastically de - tune the coil, making alignment -.- almost impossible-adjust L6 (the LO ,. . coil) until you hear aircraft or airport communications. Once you are receiving aircraft or airport frequencies, adjust TI for the best reception. Typically, T1 is adjusted 2-3 turns from the top of the shield can, If you don't have any signal -refer- The Aviation Receiver's printed -circuit board fits neatly into this optional 5- X 5.25- and x 1.5 -inch custom cabinet (which comes with knobs, hardware, silk-screened front ence equipment for alignment, and back panels, as well as rubber mounting feet). are not yet hearing airplanes, your best bet is to pack up the receiver and stalled, check your work for the usual nents, solder bridges, etc. Once the necessary alignment tools, and construction errors: cold solder joints, you've determined that the circuit has head for the nearest airport! If the air- misplaced or misoriented compo- been correctly assembled, it's time to port has no control tower, visit a gen- 33

AmericanRadioHistory.Com WHAT YOU CAN EXPECT TO HEAR

No matter where you live, you will be flight plan, which is done before con- fic Control) centers. The aircraft is really able to receive at least the airborne side tacting ground control for taxi instruc- en route on a flight, rather than just leav- of many air-traffic communications. If tions. ing or approaching a destination. A pilot you know where to tune, you can hear From the control tower, ground move- will be in touch with several different any aircraft that you can see, plus plan- ments on ramps and taxiways are han- Regional Centers" during a cross-coun- es a hundred miles away and more, dled on the Ground Control Frequency, try flight. since VHF signals travel "line of sight." while runway and in flight maneuvers Airports without control towers rely on An airliner at an altitude of 35,000 feet near the airport (takeoffs, local -traffic the local Unicorn frequency for strictly and in the next state is probably still patterns, final approaches, and land- advisory communications between pi- line -of -sight to your antenna. ings) are on the Tower Frequency. ATIS, lots and ground personnel, such as fuel Similarly, whatever ground stations or 'Automatic Terminal Information Sys- service operators. The people: on the you may hear are also determined by tem," is a repeated broadcast about ground can advise'the pilot what they the line -of -sight character of VHF com- basic weather information, runways in know about incoming or outgoing air-, munication. If there are no major obsta- use, and any special information such craft, but the pilot remains responsible cles (tall buildings, hills, etc.) between as closed taxiways or runways. Such a for landing and takeoff decisions. Typ- your antenna and an airport, you'll be broadcast offers an excellent steady ical Unicorn frequencies are 122.8 and able to hear both sides of many kinds of signal source for initial adjustment of 123.0 MHz. aviation communication. Be prepared your receiver, if you are close,enough to The FAA's network of FSS (Flight Ser- for them to be fast and to the point, and the airport to receive ATIS. vice Stations) keeps track of flight for the same airplane to move to several Approach Control and Departure plans, provides weather briefings and different frequencies in the span of a few Control are air-traffic radar controllers other services to pilots. Some advisory minutes! that coordinate all flight operations in radio communication takes place be- At most metropolitan airports, pilots the vicinity of busy metropolitan -airport tween pilots and a regional FSS. If there communicate with the FAA on a "Clear- areas. When you hear a pilot talking with is an FSS in your local area, but no air- ance Delivery" frequency to obtain ap- "Jacksonville Center" or "Indianapolis port control towers, the FSS radio fre- proval or clearance of the intended Center," these are regional ATC (Air Traf- quency will stay interesting.

PARTS LIST FOR THE AVIATION RECEIVER

SEMICONDUCTORS R19 -100,000 -ohm Key TK-2306) Ul-NE602 double -balanced mixer, R26 -22,000 -ohm S1-SPST switch, PC mount integrated circuit (Digi-Key) J1 -RCA jack, PC mount U2-MC1350 linear IF amplifier, CAPACITORS J2 -Subminiature phone jack, PC integrated circuit (Allied 858-3011) CI, C7, C8, C13, Cl6 0.001-µF, mount U3-LM324 quad op -amp, integrated ceramic,-disc B1 -9 -volt transistor -radio battery circuit (Digi-Key) C2, C4, C6-82-pF, ceramic -disc Perfboard materials, enclosure, AC U4-LM386 low-voltage audio -power C3, C5-3,9-pF, ceramic -disc molded power plug with line cord, amplifier, integrated circuit (Digi- C9, C17, C19, C20, C28, C30- battery(s), battery holder and Key) 0.01 -µF, ceramic -disc connector, wire, solder, hardware, Ql-2SC2570 or 2N5179 NPN UHF CIO, C15, C21, C25, C26, C31=4.7 - etc. transistor (Allied 858-1041) to 10-µF, 16-WVDC, electrolytic Q2 -2N3904 general-purpose NPN C11-10-pF, ceramic -disc silicon transistor (Digi-Key) C12, C14-27-pF, NPO ceramic -disc Dl-BB405 or BB505 varactor diode C18, C27, C29-100- to 220-µF, 16- Note: The following items are (Siemens, Allied 586-0610) WVDC, electrolytic available from Ramsey Electronics, D2 -1N270, 1N34, or similar C22-0,47-µF, 16-WVDC, Inc., 793 Canning Parkway, Victor, germanium diode electrolytic NY 14564; Tel. 716-924-4560: A D3 -1N914 silicon diode C23, C24 0.1-µF, ceramic-disé complete kit of parts (AR-1BP), including printed circuit board (but INDUCTORS not the case or control knobs), RESISTORS Ll, L3, L5 -11/2 -turns #24 to #30 $24.95; an etched and drilled (All fixed resistors are 1/4-watt, 5% printed -circuit board only units.) gauge wire L2, L4 0.33-µH, inductor (Digi- (AR-1PCBP), $10.00; a Special R1 -R3 -10,000 -ohm PC -mount Key M9R33-ND) Parts Kit (AR 1SPKBP) containing potentiometer - all semiconductors, L6 0.1-µH, 31/2 -turn: slug -tuned RI -R3, all R4, R9, R15, R16, R20, R21, R24- coil (Digi-Key TK2816) inductors, Si, JI and J2, and FIL1, 47,000 -ohm T1 -10.7 -MHz, shielded transformer $14.50; Custom case and knob set R5, R7,,R11, R18, R25, R27-1000= (Mouser 42IF123) (C-AR-IBP), $12.95. Please add ohm $3 for orders under $20. All orders R6, R28 -270 -ohm are subject to a $3.75 postage/ R8, R12, R17, R23 -10;000 -ohm ADDITIONAL PARTS AND handling charge. New York State RIO, R14-1-megohm MATERIALS residents, please add appropriate R13, R22 -33,000-ohm FL1-10,7-MHz ceramic filter (Digi- sales tax. 34

AmericanRadioHistory.Com 'PILOT AND CONTROLLER n n TALK R1 R2 R3 Don't blame the Aviation Receiver if all +C15 C25 you hear are short bursts of words that y -+ -R20- don't make a.lot of sense at first. Avia- j_ tion communication is necessarily '=fl24- C 8 S1 quick and brief, but clear and full of -R9- meaning; Generally, pilóts repeat ex- \ actly what they hear from a controller, so - R7 - 7 -J- -Pr- that both know' the message or instruc- C14 ' C221 tions were correctly interpreted. If you I 18= I R11 + R17I are listening in, it's hard to track every- C13 1 I9 in -R8-- R161 ' thing said from -a cockpit, particularly J- . -~D3 C11= "I - 1 Ci3 - big city areas. Just to taxi, takeoff, and C12 R10 - J - five few miles, a pilot may talk with 6 or 8 different air-traffic -control operations C10+ U1 R5 IR28 C6 within a few minutes, all on different fre- FIL1 U3 ,quencies. -R6- J R15 -C24£ Here's the meaning of just a few typical communications: - R22I -R21- III "Miami Center, Delta 545 heavy out of -C8- C21I 1.73 R14 three -zero for two -five." Delta Flight 545 +C31 acknowledges Miami Center's clear- 14 C19 U2 ance to descend from 30,000 feet to I 25,000 feet. The word "heavy" means =C17- that the plane is a jumbo jet, perhaps a '-C7- ''--'R26-5 -R12- 747, DC-10, or L-1011. -036- 432 lima cleared to outer -C6- ."Seneca L4 T1 marker. Contact tower 118.7." The local D2 Approach Control is saying that the i L5 + / + -: Piper Seneca with the N -number, or "tail C27 C4 1 1` C 2 6 number' ending in "432L" is cleared to I-05 4 -v- continue flying an instrument approach -C28- (a precision radio -C3- U4 to the outer marker beacon -located near, the airport), and -13-- -L2- I the airport ra- R27 should immediately call -C1= -7-- dio control tower on 118.7 MHz. That C2 L1 Message also implies that the controller' I I rl does not expect to talk again with that J2 aircraft., SPEAKER' a "Cessna 723, squawk 6750, climb - J1 and maintain five thousand." A control-

ANTENNA ler is telling the Cessna pilot to set the ° airplane's radar transponder to code Fig. 3. Use this parts -placement diagram as a guide when assembling the printed - "6750,- climb to and level off at the al- circuit board titude of "5000 feet." 4 _ "United 330, traffic,at 9 o'clock, eral aviation service center on the then back it off slightly (counterclock- miles, altitude unknown." The controller alerts the United -Airlines flight of radar and ask which are wise) past the pop.' You are now in airport grounds, contact with some other aircraft off to the most active frequencies. Then ad- squelch mode. the pilots left at a "9 o'clock" position. so just L6 and R1 until you hear the action. With pilots and controllers talking Since the unknown plane's' altitude is A ground -service operator or pri- briefly, you will need to get used to also unknown, both controller and pilot private. plane pilot may be willing to give you a tuning your receiver. As you sweep realize-that,it is a smaller vate not eqUipped with altitude -reporting the band (via R1), listen for a brief test transmission on the 122.8 Uni- across equipment. com frequency. Remember, also, that sound, then. rock back and forth if your airport has ATIS transmissions, slightly to tune it in clearly. IC's, diodes, and you can get a steady test signal as tion of all transistors, Also, be sure soon as you are within line -of -sight of Troubleshooting Suggestions. If electrolytic capacitors. that C11 and 012 in U1's oscillator cir- its antenna. (See the sidebar for ex- the receiver does not work at all, care- are right values. Local -os- planation of Unicom and ATIS.) fully check the obvious things first; bat- cuit of the tery polarity, soldering of the battery cillator operation can be verified with

. VHF receiver or frequency Use. Plug an antenna into J1 and a 4 - wires and switch, and the connections a simple the local os- to 8 -ohm speaker or earphone into to the speaker jack. Also, be sure to counter. Remember that set to a frequency J2. Turn on the Aviation Receiver by check that you've correctly installed cillator should be 10.7 MHz above the desired listening closing S1. You may or may not hear all of the jumpers. If the circuit's opera- range. If the oscillator works, only a background noise. Turn R2 (the SQUELCH tion is erratic, a solder connection is installed part control) fully counterclockwise. Then usually the culprit, or there could be a defective or incorrectly the rest of the receiver rotate R2 clockwise until you hear a break in the antenna or speaker wire. can prevent "pop" and some background noise; Pay special attention to the orienta - circuit from functioning. 35

AmericanRadioHistory.Com Although it may seem quite filter. The purpose of U2 and U3 -a distant now summer is ap- is to reject'spurious sounds that proaching' with the antic- Build fall a within the filter's range and to ipation of backyard games, bar- allow the dog a period of free becues, and the dog next door barking. barking incessantly. If you happen ilk, If the counter (U2) counts 256 to be the owner of irritating, ,te the lbark pulses within eight seconds,. barking dog next door, then neigh- its ;@ output goes high. That high is borhood harmony is risk, But, at inverted by U4 -b and applied to worry not... for in this article, we're r. the trigger input of U3 -b at pin 8, going to show you how to a f9 build forcing its output at pin 9 high. Dog Bark Inhibitor that will restore The high output of U3 -b is applied neighborhood harmony by hu- to the base of Q1 (an MPSA12/ manely stopping your dog from Darlington transistor), causing it tó barking. conduct. With Q1 conducting, BZ1 Commercially available dog (a 6 -volt electronic buzzer) acti- bark inhibitors (electronic devices Dog -Bark vates for about half a second. At built into a dog's collar) that are the same time, the ripple counter currently on the market are both (U2) is reset via an oa gate, made expensive and can in some circles up of D1, D2, and R11. be considered inhumane. With Inhibitor If, on the other hand, U2 counts such devices, every time the dog fewer than 256 pulses within that barks an Give yourself and your electrical charge is sent 8 -second period, the counter re- to the dog's neck. While that stops neighbors some peace sets, and awaits the next barking the dog from barking, it can also session. turn a dog into a cowering animal and quiet with this The circuit is powered by a 9 - afraid of its own shadow. volt transistor-radio battery. Be- However; the training aid Dog Bark Inhibitor cause. of that, the semiconduc- described is 'here inexpensive and BY ROBERT J. GAFFIGAN JR. tors used for this circúit were humanely. stops the dog from bark- chosen for their low -current re- ing by actuating a buzzer every time the circuit is determined by the gains qúirements-the circuit draws ap- the barking' begins. The buzzing is provided by .U1-.a and U1 -d. The hys- proximately 0.9 microamps of quies- used to give the dog negative feed- teresis provided by those two op - cent current, and 15 mA with the back that he'll with associate his barki- amps helps to keep background buzzer on-and should not be sub ng, causing him to refrain from that noise out of the signal applied to U1 -b, stituted unless swapped for lower - annoying tendency. which is setup as a low-pass filter. That power components. low-pass filter is used to remove fre- Circuit 1 Description. Figure shows quencies from the signal that are not Construction. Although the author's a schematic diagram of the Dog Bark in the range of a dog's bark. prototype was built on a section of Inhibitor. At power up, a one-shot mul- From the filter, the signal (see Fig. 2B) perfboard, using point-to-point wiring tivibrator, of consisting one-third of a is made compatible with digital cir- 'to interconnect the circuit elements, 40106 he Schmitt trigger (U4 -c and cuitry by U4 -a (Ye of a 40106 hex invert-, the final version was assembled on a U4 -d), resets U2 and U3, keeping the ing Schmitt trigger), which also inverts printed -circuit board, measuring buzzer (B21) cut off. At the same time, the input signal. That signal is again about 3 x 2 inches. A template of the resistors R1. and R2 set the trigger level inverted by U4 -f and output to the fol- printed -circuit layout is shown in Fig. 3.' of U1 -a, U1-c;and U1 -d (3/4 of an LP324 lowing circuitry as a train of negative - You can etch your own printed-circuit quad op -amp) to 2.5 volts. Op -amps going pulses. Those pulses are pro- board from the template shown in Fig. U1 -a and U1 -d are configured as induced each time that the sound 3, or you can order a printed -circuit verting comparators with hysteresis, picked up by the microphone falls board and the parts (separately) to while U1 -c is as configured a voltage within the low-pass range of the filter. populate it from the supplier listed ih follower. (see the waveform in Fig. 2C). the Parts List. The voltage follower (U1 -c) provides The output of U4 -f divides along two Once you have obtained the a DC standing' bias voltage for an signal paths: in one path, the signal is board and the parts that go with it, electret microphone (MIC1). When fed to the clock input of U2 (a 404012 - construction can begin. Figure 4 MIC1 picks up the dog's barking (see stage ripple carry binarycounter); in shows the parts -placement diagram the in waveform diagram Fig. 2A), the the other path, the signal is applied to for the author's printed -circuit layout. It bias voltage applied to MIC1 fluctu- the trigger input of U3 -a (Y2 of a 556 is recommended that IC sockets be ates, and the output of U1 -c follows. dual oscillator/timer). The negative provided for all of the DIP units (U1-U4). Fluctuations in the microphone's bias pulses trigger U3 -a, whose output, in The regulator, U5, is housed in a TO -92 voltage are applied to U1 -d, which turn, enables U2, causing it to count style package. Begin construction by amplifies the signal and feeds its out- the number of times that the sound installing the DIP sockets: and the 36 put to U1 -a. The overall sensitivity of falls within the low-pass range of the jumper wires. Once that is done, install

AmericanRadioHistory.Com { R10 56K SOUND Cl 1M 39K R4 R5 MIC1 2.2 1/4 LP324N 13 39K R12' 75K 1 10K R6 R7 R8 2 13 U1 -d 2.2K. 11K 11K U1 -b 12 %14 + / C2 01-a + / U4 -a U4 -f :047 +: C5 1/4 LP324N C4 Vs 40108 1/8 40108 R3 - 1/4 LP324N 1K _ C3 .01

+5V +5V SOUND

4 16 +5V +5V R1 +5V 4 CLK D U4 -e 100K 8 U2 01-c 1/8 40106 14 9 U3 -b 8 3 4 4040 1/4 LP324N 1 11 }tl4 1/2 L558 RST 11 R2 U4 -b 08 D2 U3 -a 12 13 10 7 100K 1/6 1/2 L558 40108 .23 13 1N914

+5V 4 1 2 +5V R16 f--, N --

BZ1 100K . D1 R11 `'vvb-- R13 R15 1N914 100K 1MEG C8 1MEG 1

C6 + (LIZ1 8.2 Al2 U4 -c ' U4 -d S1 1/e 40108 1/6 40108 R14 1MEG 6 5 8 +5V VA +5V SOURCE + C7

(U2), an Fig. 1. The Dog Bark Inhibitor is comprised of an LP324 quad op -amp (UI), a 4040 12 -stage ripple carry binary counter LM556 dual oscillator/timer (U3), a CD40106 hex inverting Schmitt trigger (U4), an LM2931A 5 -volt series, low -dropout, voltage regulator (U5), an MPSAI2 Darlington transistor (QI), two 1N914 general-purpose, small -signal silicon diodes (DI and D2) and a handful of additional components.

(MIC1) was mounted directly to the, circuit board, although it might appear otherwise in the parts-place- RF1 A ment diagram. GND r PIN 14 U1 -d' It will be necessary to prepare the enclosure that is to house. the circuit board and the off -board components. The author's unit was housed in

1 1 j l 1 4 1 111+j 1 1.1 1 1411 1111 a plastic project box with a metal lid, B measuring about 31/4 x 21/8 x 1 CH1 PIN 7 U1 -b GND 7 inches. Begin preparing the en- r i closure by first placing the circuit board into the enclosure to deter- ---- a --M C mine where the microphone will be CH2 F., PIN 12 U4 -f located when it is permanently GND ,.. mounted. Mark that position on the wall of the enclosure, and drill several I I I 1 I I I tiny holes at that location. Fig. 2. Shown in A is the waveform produced at the output of pI-d when the dog Next, on the same side of the en- barks; B shows the same waveform after it has undergone filtering; -and C shows how closure, drill two holes (one near each the waveform looks after being processed for application to the digital circuitry that follows. end), which will be used to mount a nylon web strap (dog collar) to the the passive components (resistors they will be installed in their respective project box. Then make two cutouts at and capacitors). sockets later), and connect a 9 -volt opposite ends of the enclosure for the After the passive components have battery connector to the appropriate buzzer (BZ1) and the slide switch (S1); been installed,mount the active points on the board. In the author's the cutouts should be approximately components (excluding the DIP IC's, prototype unit, the microphone '/8 x 5/8 inches for the buzzer, and the 37

AmericanRadioHistory.Com PARTS LIST FOR THE DOG BARK INHIBITOR

SEMICONDUCTORS Ul-LP324 micropowe'r quad op -amp (National), integrated circuit U2-CD4040 12 -stage ripple carry binary counter, integrated circuit U3-LM556 dual oscillator/timer, integrated circuit U_ 4--CD40106 hex inverting.Schmitt- trigger, integrated "circuit U5-LM2931A 5 -volt series, low - 21/e INCHES dropout, voltage regulator, integrated circuit Fig. 3. The final version of the circuit was assembled on a printed -circuit board, Ql-MPSA12 Darlington NPN measuring about 3 x 2 inches. A template of that layout is shown here full size. silicon transistor DI, D2 -1N914 general-purpose, small -signal silicon diode RESISTORS (All fixed resistors are 1/4 -watt, 5% units.) RI, R2, R11, R16 -100,000 -ohm ('C-TJ R3 -1000 -ohm \ R5 R12I, R4, R9 -39,000 -ohm C2 R5 -75,000-ohm R6-2200 -ohm R9IC4I"IC3 R6 R7, R8 -ohm -11,000 CSI R7I IR R10-56,000 -ohm' R12 -10,000 -ohm R13-R15-1-megohm CAPACITORS 16-WVDC, tantalum i C.g C2-0.047-µF, monolithic C3 -0.I -µF, monolithic C4, C5-0.01-µF,.monolithic C6 -8.2-µF, 16-WVDC, tantalum C7, C8 -1-µF, 16-WVDC, tantalum Fig. 4. Once you've obtained the board and the parts that will populate it (either on C9-22-µF, 16-WVDC, miniature your own or by ordering them from the supplier listed in the Parts List), use this parts - electrolytic placement diagram to locate and install the components in their proper positions.

ADDITIONAL PARTS AND other approximately 5/,e x 1/4 MATERIALS inches Operation. Using the circuit is easy. Sl-SPST slide switch for the slide switch. Simply strap the Dog Bark Inhibitor to Connect short lengths of hook-up your dog's neck (be sure to orient the k MIC1-Electret microphone BZ1-6-volt electronic buzzer (RS wire to the buzzer and the switch, con- unit so that the microphone is up), turn #273-054) nect the wires from the off-bowd the unit on using S1. Any long duration B1 -9 -volt transistor-radio battery components to the appropriate or repeated barking by the dog will Printed -circuit materials, enclosure, points on the printed -circuit board. cause the buzzer to sound for one half 3/4 x 24 -inch web strap, adhesive Mount the printed -circuit board, second. If greater sensitivity is desired, backed cushion feet, battery holder switch, and buzzer to the enclosure, increase the value of R5. and connector, wire, solder, and then secure the nylon web strap A longer free -barking period hardware, etc. can to the side of the enclosure using a be achieved by increasing the Note: The following. items are pair of 4/40 screws and nuts. The strap- number of counts U4 allows before available from Futronics, 22524 ping used to secure the projept to the turning on the buzzer (that can be Millénbach, St. Clair Shores, MI dog's neck is available at most sports done by cutting the trace to pin 13 of 48081. A complete 'kit of parts, and army surplus stores. U2 and moving the 'wire to $29.95; printed -circuit board only, the Q9 Cut off any excess strap length after Output pin 12 $9.95. Please add $3.00 for or the Q10 output pin 14). shipping and handling. Michigan sizing it to the dog's neck; the free end The project has been used on the au- residents please add appropriate of the strap should be melted to avoid thor's dog for more than a year and sales tax. fraying. Finally, install the IC's in their has stopped the dog's nuisance barki- respective sockets, install a 9 -volt bat- ng and has restored neighborhood 38 tery, and close up the project box. harmony.

AmericanRadioHistory.Com On -Boar Navigation Systems \ for your Car

On -board navigation systems, satelite positioning, roadside beacons, and many more developments may dramatically change the relationship between man and his car.

BY BILL SIURU

in IIis your first trip to this city and you pass direction and the mileage to listing of motels and hotels a famil- have much business to conduct. your destination. This trip is going to be iar Yellow Pages format. You choose You don't have any time to spare, a piece of cake! one and then use the cellular phone especially driving around lost. There- Moving out of the parking garage, to make the reservation. As you go fore, you spring for a deluxe rental car you glance to your right and see the through this menu, you note for later complete with an on -board naviga- mop moving with the vehicle as you reference that there are also listings of tion system and cellular phone. turn right or left, or even back up. To restaurants, entertainment attrac- Slipping behind the wheel, you help keep your Orientation, the top of tions, towing services, and even local immediately notice the small CRT the screen represents "straight happenings with dates, locations, screen in the center of the dash- ahead." Halfway to your destination, and times. board. After reading the .brief User- the system starts "beeping" quietly to Sounds like a bit of science fantasy? friendly instruction pamphlet, you flip get your attention. Without taking your Well, in -car navigation systems with at on the ignition switch and the screen eyes off the road, you notice a "con- least most of these capabilities are lights up with a monochromatic map gestion" warning and a new route is starting to appear on the market in of the city's streets. An icon' on the suggested to avoid the problem. As Europe, Japan, and even the U.S. For screen displays your current location. you near your destination, you press instance, some 50,000 navigation sys- Pressing one of the buttons along the another side button to zoom -in on the tems are already in operation in Ja- side of the CRT, the map changes to a display so the local streets are shown pan. In Europe and the U.S., menu. Scrolling through the menu, in greater detail. navigation equipment is starting to you enter your first destination, Switch- After parking, but before leaving appear in police cars, fire trucks, am- ing back to the map display, you see the car for your appointment, you re- bulances, express delivery vans, and another icon at the destination plus member you need to make a hotel other time -critical vehicles. "Civilian" the streets you have to travel high- reservation. Pressing another button affermarket units are now on sale in lighted. Also shown is the current corn - brings up a menu that gives you a the U.S. as well. 39

AmericanRadioHistory.Com How They Work. Let's look at the 1). The two wheel sensors determine get from point A to point B. The dis- Bldupunkt Travelpilot by the Robert when the car is turning and moving at tance and compass direction to the Bosch Corporation, which is already different speeds. The heart of the Trav- selected destination is also shown. offered in the United States as well as elpilot system is the "black box" lo- The map display scrolls and rotates in Europe with a suggested retail price . cated in the car's trunk or under the under the fixed cursor placed over the of $2,495. The Travelpilot uses "dead - seat in commercial vehicles. Inside is ever-changing current location. Map reckoning" navigation, a technique a 600 -megabyte CD-ROM player and movement corresponds to the car's first used by mariners and aviators, a navigational Computer. The com- movement on the map and the road. combined with map matching. pact disc stores the EtakMap digitized Destinations can be selected by city Dead reckoning uses speed, time, maps of the required geographic re- locale, street address, or the intersec- and compass direction to continu- gion used for map matching. The Trav- tion of two streets. Up to 99 user -pro- ously compute the vehicle's estimat- elpilot computer consists of a 16 -bit grammed destinations can be stored ed location with respect to a known processor with 8k SRAM, 64k EPROM, in the memory. According to position. Dead reckoning is some- and 512k DRAM. Blaupunkt, a vector-type video dis- times referred to as "deduced reck- The Travelpilot's real-time moving play was chosen for the system be- oning." That is because you are map display (see Fig. 2) shows current cause it is easier to read than a TV- deducing where you must now be location and the alternate routes to style raster -scan display. The driver given that you have, for example, traveled for 15 miles (determined by an odometer or a speedometer and a clock) due east from a known starting position. In simple dead reckoning, you would plot your course on a map with a pencil. That roughly corresponds to map matching in a navigation system like the Travelpilot. Here the path being driven (determined from dead reckoning) is compared, or technically called "cross -correlated," with the available paths -that are on the map. That is like tracing your path on a piece of paper, putting it over a map and moving it around until it matches up with the roads on the map. Of course, in a computerized navigation system, this correlation is done using Fig. 1. The computer and CD ROM of the Blaupunkt Travelpilot are located in the hundreds of algorithms (comput- trunk. The electronic flux -gate compass is located over the rear window, and speed erized equations) and a digitized - sensors are located in the rear wheels. map database. Therefore, if you have driven a path on existing roads, it will correspond to a particular path in the BLAUPUNKT TRAVELPILOT map database. Even if you drive off VEHICLE NAVIGATION SYSTEM roads and into parking lots, the al- DISTANCE TO DIRECTION TO COMPASS DESTINATION LOCATED gorithms look at the "bigger picture" DESTINATION DESTINATION NORTH BETWEEN TWO STARS to find out where you probably are. Speaking of maps, Etak Inc. in Men- *MAIN MENU r ' to Park, California is the major pro- ZOOM OUT `MAP TOP NORTH ducer of digitized maps for use in on- MAP SCALE /s -SO board navigation systems as well as DESTINATION INFO MI. °- many other applications from taxi OTHER ST. NAMES 0 1 MILE SHOWN a, and ambulance dispatchers to SHIFT CURSOR LEFT OR RIGHT j public utilities and travel agents. ZOOM IN Some 75 -percent of the U.S. is aw- CURRENT LOCATION Rue~ 1 ered by at least one version of an AND DIRECTION CURRENT TRAVEL DESTINATION 2 EtakMap digitized map, as are exten- OF á BRIGHTNESS sive areas of Germany, France, and CONTROL the Netherlands. uses an electronic flux - Travelpilot NO ACCESS WHEN VEHICLE IS MOVING. 2 gate compass and dual wheel sensors to measure direction and dis- Fig. 2. This is the display CRT for the Blaupunkt. Control buttons are located along 40 tance traveled, respectively (See Fig. either side, as shown.

AmericanRadioHistory.Com can zoom the display in or out for IR -DATA TRANSCEIVER more or less detail as is needed.

Obtaining More Accuracy. In the DISPLAY UNIT simplest case, you could dead reckon CABLE 0 4 with nothing more than a compass DISTRIBUTION BOX - and odometer, plus a map and pencil. However, these "sensors" are pretty crude and location errors can quickly accumulate. Even precision wheel - MAGNETIC flux -gate com- FIELD SENSOR speed sensors and VEHICLE WIRING passes are not prefect. Therefore, IR -KEYBOARD LEFT FRONT SPEAKER while on -board navigation systems OF VEHICLE RADIO like Travelpilot can be completely self- Fig. 3. These are the in -vehicle components for the Ali -Scout navigation system. Note contained and give good results, the IR remote keyboard used for entering data and controlling the system. many on -board navigation systems use external and/or internal methods to further improve their accuracy. Ex- ternal sources involve interfacing with the Global -Positioning System (GPS) ANGLE OF DEFLECTION satellites in space (for more on this, POLARIZER see the July, 1992 issue of Popular Electronics), Loran transmitters, or roadside and overhead beacons. The downside is that these interfaces usually require user fees or, for example in PHOTODIODE . the case of beacons, major invest- PHASE MODULATOR ments in infrastructure. Internal methods, on the other hand,. require additional inertial -guidance components. However, map matching is still a OPTICAL-FIBER COUPLERS necessary ingredient to precisely lo- the vehicle on the map in just cate PHOTODETECTOR about every system. The prototype Motorola In -Vehicle Fig. 4. This is a depiction of the optical fiber gyroscope used in Nissan's new on- Navigation System uses position data board navigation system available in Japan. Any angular deflection of the large disk from GPS satellites to enhance the ac- results in a variation of angular velocity in the fiber. curacy of the vehicle's current location. Besides GPS data, the navigation coherent radiation source, simulta- using somewhat more distracting computer receives measurements neous infrared flashes can never map displays, the Ali-Scout uses a from a differential odometer and extinguish each other, only cmplify dashboard display with simplified magnetometer to provide dead reck- each other. Even the most compli- graphic symbols for. instructions. For oning. A digital map stored in the CD cated intersections pose no problems example, arrows show turn directions in size as ROM is used for map matching, route with IR, The IR signal is transmitted at a and a bar graph decreases planning, and route guidance. Drivers 125k baud rate at a maximum range the corner approaches. The visual dis- are provided instructions via both a of 60 meters (200 feet) so that the play is augmented by audible instruc- simplified dashboard video display vehicle is only within the transmission tions as well. A 36 -key handheld and synthesized voice commands. range when passing near the alphanumeric keyboard is used for in- Germany's Siemens Automotive Ali - beacon. putting destinations either in the form Scout navigation system (see Fig. 3) The Ali -Scout's dead reckoning nav- of street names or map coordinates. communicates with infrared beacons igation computer uses measurements The memory has the capacity for 100 mounted on existing traffic lights. An from a magnetic -field sensor that destinations. Some other navigation infrared transmitter/receiver mounted measures the earth's magnetic field. systems allow both maps and sym- on the back of the rear-view mirror Distance travelled is determined bolic instructions by changing dis- screen. receives information from the . using a speed sensor attached to the plays on the beacons. Infrared communication odometer or transmission. Several navigation systems are al- in was chosen because IR diodes emit One potential problem with on- ready coming into routine use Ja- incoherent beams eliminating inter- board navigation systems is that com- pan. For example, Nissan has just ference problems caused by multi - plex map displays can overtax driver introduced its third -generation vehi- path propagation or when several attention especially when trying to cle -navigation. system that is optional transmitters are operating in mutually cope with demanding urban -traffic on its Cedric, Gloria, and Cima mod- The overlapping regions. Being an in - conditions. Therefore rather than els sold in their home markét. sys- 41

AmericanRadioHistory.Com tern uses a new optical -fiber gyro- central point, destinations of roads fic congestion and its byproducts: scope (shown in Fig. 4) to accurately leading from the intersections, road wasted fuel, additional pollution, sense the direction of vehicle motion. restrictions, and more. The optical -fi- wasted time, and frayed nerves. There The gyroscope uses 100 meters of 0.3 - ber gyroscope and roadside are several major Intelligent Vehicle/ mm optical fiber coiled into a 130 - beacons are used with dead reckon- Highway System (IVHS) demonstration mm diameter loop. The gyroscope ing and a digital -map database to projects underway in several coun- measures angular velocities by deter- provide greater accuracy than pre- tries that mate on -board navigation mining the difference in the time of. vious Nissan systems, which relied only equipment with centralized traffic: light traveling clockwise versus coun- on position updates from GPS satel- management systems. terclockwise in the circular optical -fi- lites. The $12 million Travtek (which ber path. The time differences, which Nissan uses a dual -system map - stands for Travel Technology) experi- are actually frequency shifts, can be matching logic. In the micromatching mental program in Orlando, Florida correlated with the rate of angular mode, the calculated vehicle loca- probably represents the most am- motion. Bumpy roads are no problem tion is matched every second to bitious IVHS demonstration project un- this because type of gyro is not af- roads in the internal map database. derway in the U.S. toddy. For this one- fected by shock in the horizontal Here the searching is done in a small year demonstration program, 100 plane. zone by detecting the angular ve- Oldsmobiles have been fitted with an Nissan also uses roadside elec- locity of the vehicle. jn the macin -dash CRT monitor, TravTek naviga- tronic beacons that broadcast their romatching mode, matching is done tion hardware and software, plus ra- specific location coordinates via dig- about every 50 -meters of travel to dio gear for two-way communication ital broadcasts at 2,5 GHz. They are compare vehicle direction with road- with the Orlando Traffic Management deliberately weak to limit the recep- way shapes. -Searching in the mac- Center. Seventy-five of these specially tion area to approximately 35 meters romatching mode is done in a wider equipped cars are part of Avis' rental - before and after the beacon in a strip zone using 5 -kilometer segments. The car fleet in Orlando. The rest will. be that is only about 15 meters wide. This map database is stored on a single evaluated by high -mileage drivers. avoids any possibility of cross -beacon CD ROM, According to Nissan, vehi- TravTek is a joint program with the inteference. Beacons are already cles can be located within five American Automobile Association, being set up along major roadways in meters. General Motors, the Federal Highway Tokyo, Osaka, and Nagoya, with even Administration, Florida Department of more beacons to be installed in the More Than Finding Your Way. Transportation, and the City of Orlan- future. Data broadcast by the Probably the greatest contribution do. beacons include intersection names navigation systems can make to so- For navigation, TravTek uses com- and coordinates, distances from a ciety is helping to reduce urban-traf- puterized dead reckoning and map matching with updates from the GPS satellites to TRAVEL TECHNOLOGY pinpoint vehicle location within a 1200 square -mile area that VARIOUS AGENCIES, FLORIDA DEPT. OF includes 10,000 roadway miles. After DEPTS., ETC. TRANSPORTATION the driver enters the desired destina- INCIDENT tion, TravTek computes the best route INFORMATION FRÉEWAY and then guides the driver tó the des- MANAGEMENT CENTER tination using both visual and syn- FEDERAL HIGHWAY thesized voice commands. ADMINISTRATION/ TravTek is much more than an on- ORLANDO board navigation system. It also ad- TRAFFIC vises drivers INFORMATION of traffic congestion and TRAFFIC delays (see Fig. 5). Besides warnings, ' MANAGEMENT TRAFFIC DATA the CENTER system automatically provides re - routings to avoid the problems using TRAVEL/EVENT advisories transmitted from the Traffic INFORMATION Management Center. The in -vehicle TRAVEL LOCATION TravTek processor receives the adviso- TRAVTEK TIMES INFORMATION ries, then determines if the driver's se- AND SERVICE lected route is affected, calculates a CENTER new route and informs the driver that TRAVTEK GENERAL an alternate route is available. These AMERICAN VEHICLES AUTOMOBILE MOTORS CITY OF ORLANDO advisories are generated using data ASSOCIATION o from several sources including the GUIDANCE CELLULAR city's centralized traffic signal system, TELEPHONE INFORMATION the Florida Department of Transporta- tion's freeway -management system, Fig. 5. This block diagram shows the interfaces between on -board equipment, the AAA TravTek information sources, and the Traffic Management Center that is being used in Information and Ser - 42 Orlando's TravTek system. (Continued on page 92)

AmericanRadioHistory.Com A Telephone -Líase

ow many times have cy oscillator; the other two you lifted the tele- -..1:0 gates (U1 -a and U1 -b) are phone receiver from .s, used to buffer the output of the hook, in a vain attempt 'he oscillator, which is used to make an important call, to drive LED1.

- ;1 Resistors R1 the only to find that the phone is -R3 sample in use. Or, what about those phone line voltage and di- times when you're involved vide it to one third of its origi- r I in a confidential call and nal value. When the voltage somebody lifts the receiver w across R2 exceeds 5 volts, (in- fi off hook just in time to hear dicating a phone line voltage of at least 15 volts), the just enough of the dialogue 4. to misconstrue the meaning oscillator is gated off and of your conversation. Or LED1 remains dark. maybe while you're trying to When the telephone rings, 100 upload or download a time - the line voltage goes to dependent, critical cornput- volts AC, which puts 33 volts er document, someone across R2. That is beyond the takes a remote receiver off maximum rating of the allowing noise (which CMOS IC, not to mention hook, 1 L can lead to glitches) to get . that the polarity is backward into the transmission. Such half thé time. $o why doesn't events can lead to inter- the IC fry? The answer has to family conflicts. do with the input protection Wouldn't it be nice if your diodes built into every B -se- home telephone contained ries CMOS logic chip (see circuitry that would let you ., Fig. 2). Because R1, R2, and the Input cur- know when the line is being R3 are so large, is when the used (a feature that is readily rent tiny even available in most office en- I voltage is very high. The di- -1 inside the chip shunt vironments). Well, with the - Line -In -Use Indicator de- the excess voltage to the scribed in this article, you battery, which absorbs it. can add such a feature to Since the current is only a your present home -tele- In -Use couple of microamps, it has phone network. The circuit- no effect on the battery. which uses a bright, blinking LED to indicate whether the Construction. The author's Indicator prototype was assembled line is in use-can be installed next to any tele- on a small section of per- phone to warn other family members Keep others from barging fboard. As always, it is recommended not to interrupt your modem connec- that an IC socket be provided for U1. tions or private conversations. in on your telephone Begin construction by first mounting a conversations 14 -pin IC socket to the perfboard. Flip How It Works: The indicator works the board over and then mark the pin by sensing the voltage across the tele- 1 terminal of the socket, which will Now, phone line. The line voltage is nor- BY MICHAEL A. COVINGTON serve as a reference point. to- mally 48 volts DC when the phone is guided by Fig. 1, wire the circuit on hook, and drops to about 2 to 10 available to light an LED brightly. The gether using point-to-point wiring volts when a telephone is off hook. power supply arrangement used for techniques. When the voltage across the tele- the project ensures that the LED is al- When it comes to the LED, there are phone line drops below 15 volts, an ways bright and prominent. a couple of ways to handle it. The LED LED begins to blink. While many cir- Figure 1 shows a schematic di- can be wired to the board using cuits of this ilk pirate power from the agram of the Line -In -Use Indicator. At hook-up wire, or it can be installed phone line for their operation, this one the heart of the circuit is a CD4001B with its leads left long enough so that doesn't.,. it is powered from a 9 -volt quad CMOS NOR gate. Two of the LED lens protrudes through the en- transistor radio battery. The reason is gates from that chip-U1-c and U1- closure's front panel. that there isn't always enough power d-are configured as a low-frequen- After the circuit has been as- 43

AmericanRadioHistory.Com R4 4.7 R5 PARTS LIST FOR THE MEG 4.7 1/4 C040018 12 TELEPHONE LINE -IN -USE MEG GREEN 11 10 INDICATOR 13 o yy` 1+V4.- U1 -c { 8 R1 C1 1/4 CD4001 B 7 SEMICONDUCTORS 22MEG .04 U1--CD4001B (or MC14001B) quad CMOS NOR gate, integrated circuit LEDI-Light-emitting diode, any TO 1/4 CD4001 B color TELEPHONE 3 2 LINE RESISTORS R2 6 4,0.4 (SEE TEXT) (All resistors are Vs -watt, 22MEG 14 R6 5% units.) 1/4 C04001B 27012 LED1 RI, R2, R3-22-megohm R4, R5-4.7-megohm B1 R6-270 -ohm _ R3 , 9V 22MEG ADDITIONAL PARTS AND o-VNr w MATERIALS RED C1 -0.04-µF or 0.05-µF, ceramic - Fig. I. At the heart of the Line -In -Use Indicator is a CD4001B quad CMOS NOR gate. disc capacitor Two of the gates (Ul-c and U] -d) are configured as a low frequency oscillator; the B1-9 -volt alkaline, transistor -radio *other two gates (U1 -a and Ul-b) are used to buffer the output of the oscillator, which is battery to used drive LED]. Perfboard materials, enclosure, 14 - pin IC socket, battery connector, wire, solder, hardware, etc.

telephone line through the appropriate hole in the enclosure and connect it to the circuit. The type of wire and the termination used for that will be determined by the terminal block used in your phone installation. The author used Iwo lengths of wire that he twisted together (as in "twisted pair"). However, if your home -telephone network has modular jacks, modular cable is the way to go; in that case, simply connect the red and green wire of a modular telephone cable as shown in Fig. 1. Once the cable is connected, the LED can be press -mounted in the front panel LED É hole.

The author's prototype was assembled on a small section of perfboard and housed in a Installation. Installation is a simple plastic enclosure that comes complete with a built-in battery compartment. procedure; just connect the cable from the project across the telephone D sembled, check your work for con- line, as indicated in Fig. 1. Resistor R1 struction errors, particularly around should FRAGILE go to the positive (green) wire MOSFET the IC socket. If all is well, install the IC and R3 to the negative (red) wire. In NEEDING in its socket. normal operation, the LED will be off if PROTECTION The author's prototype was housed the line is idle; the LED will blink if a in a plastic enclosure with battery telephone is off hook, a ringing signal INPUT compartment (available from Radio is present, or the line is dead (0 volts). If Shack as part 270-293). The only en- the LED never stops blinking, try swap- closure preparation required is to drill ping the connections. o Vss two holes in the enclosure; one in the Don't install the battery until you're Fig. 2. When the telephone rings, the front panel of the enclosure through ready to line voltage rises to 100 volts AC, connect the .indicator to the placing 33 volts across R2. That voltage, which LEDI will protrude, and the phone line; if you do, the LED will blink which is applied to the input of U1 -d, other in the side of the enclosure for a constantly and run the battery down. would normally fry the chip, but because telephone line cord for connection lo Conversely, don't leave the indicator the CD4001B has input protection diodes the board. attached to the line without a battery (as shown here) built into it, that doesn't Once the holesare drilled, feed the installed; it relies, on the battery for 44 happen in our circuit. wire that will connect the circuit to the overvoltage protection.

AmericanRadioHistory.Com In these difficult throughout the wiring economic times, system. The circuit's many home own- 250 -Hz squarewave ers are opting, wher- output, which is rich in ever. possible, to do B harmonic signals that their own home re- reach into the AM pairs and remodeling. broadcast band, al- Do-it-yourself home lows the signal to be repairs often entail traced through the ,ii.0, i 17vac/ti< spending many hours house or other wiring trying to trace the AC with an inexpensive LOOP AM transistor radio. The wiring through walls ON OPEN C . radiated signal, when and junction boxes. 1' CLOSED LOOP Remodeling, such as t,OM - detected by an AM re- OFF ,,) .( ceiver, produces a adding a 'new window '=:: 7,,, . or door to your home, ,-.z.:. '+w,=, : sf buzzsaw-like sound in _;;';:;.::::y ; the receiver's speaker. often requires that you . . ;_ ;. cut a section out of a In the other path, ' :....I"^., ^' , the signal goes wall. When hacking McTRAK ,. ..3e. through C4 and is de- through a wall, you WIRE .b .: had better know the livered to output jack location of the elec- TRACKER A J1 (the open -loop out- ° ', i. put); the signal also trical wiring or it's lights _ :,~ .° continues on through out. i- A simple solution to 47 -ohm current -limit- those and other similar ing resistor R6 (which is wire -tracing dilem- used to protect the mas-such as tracing tracker's output from a signal through your overload) to J2 (the automobile's elec- closed -loop output). trical system can be Those output jacks, along with J3 (com- found in the McTrak . h P wire -tracing circuit de- mon), are used when scribed in this article. conditions are less The McTrak can turn a Cut those seemingly insurmountable wire -tracing than optimum. (We'll job that might other- give examples of how wise require hours of jobs down to size and when to use those cutting, whacking, jacks at the appropri- .and pulling into child's play (well al- BY CHARLES D. RAKES ate time later in this article,) most), cutting your work time from a few hours to only a few minutes. causes Q1 to switch on and óff in time Construction. Building the McTrak is The McTrak is easy and inexpensive withthe drive signal. simple and the parts layout is not crit- to build, and best of all, there is The output of Q1, taken from its col- ical, so just about any construction nothing difficult about using the unit. lector, is fed through capacitor C2 to scheme will suffice. However, the au- All you have to do is connect the Q2 and Q3-a second 2N3904 NPN thor's prototype of the circuit was as- McTrak tó the wire of interest and, unit and its companion 2N3906 PNP sembled on a printed -circuit board. A using a portable AM receiver, trace a transistor, respectively-which form a template for that printed -circuit signal (put out by the McTrak) to its complementary pair. Together, those layout is shown in Fig. 2. If you opt to go final destination. transistors alternately amplify both the printed -circuit route, follow the halves of the applied signal;. e.g., parts -placement diagram shown in How It Works. A schematic diagram when one transistor is off the other Fig. 3. of the McTrak is shown in Fig. 1. At the one is on. That pair of transistors pro- As usual, start by installing the pas- heart of the.circuit is a 567 tone de- vides a low output -impedance signal sive components (resistors, capaci- coder. The tone decoder (U1) is con- source that can be used to drive ei- tors, etc.) followed by the semicon- figured as a simple astable, square - ther an open- or closed -loop circuit. ductors, double-checking all part wave oscillator, operating at about The output of the complementary locations and their orientations as 250 Hz. The 250 -Hz output of the pair (Q2 and Q3) splits along two they are installed on the board. Once squarewave oscillator, at pin 5, is fed paths; in one path, the output of the the electronic components have to the base of Q1 (a 2N3904 general- complementary pair is applied to C5, been installed, connect a 9 -volt bat- purpose NPN transistor), which in this causing the 250 -Hz output of the tery connector to the board at the application, functions as a buffer complementary pair to be induced points indicated in Fig. 3. Be sure that stage. The alternating output of U1 into the AC wiring and radiated the proper polarity is observed. 45

AmericanRadioHistory.Com ....---ii- side and prepare the enclosure. The o pS1 author's prototype was housed I in a 45/8 x 29/16 x 19/16 R4 -ill -inch plastic 10K +9V project box (available from Radio

R3 Shack and other sources) that is slot- 1K ted to hold small circuit boards in 02 2N3904 place. The circuit board was sized to fit < R2 the case's internal slots. 4.7K C4 C6 It will be necessary C2 y PL1 to drill holes in 47 .01 4.7 1 Z 117V the enclosure for the off-board com- 03 J1 ponents: S1 (along with its mounting 2N3906 R6 OPEN LOOP 01 4712 hardware), J1 -J3, and PL1. Note that 2N3904 J2 although the author used a slide R5 CLOSED LOOP switch for S1, there is no reason that a 10K J3 toggle or even a locking pushbutton ° COM. (push on/push off) switch could not be substituted. Mount switch S1 to one At the Fig.]. heart of the McTrak is a 567 tone decoder, configured as a simple squarewave side of the cabinet, and thé three out- oscillator, operating at about 250 Hz. put jacks on the opposite side. Then

PARTS: LIST FOR THE MCTRAK SEMICONDUCTORS electrolytic Ul-LM567 tone -decoder, integrated C5, C6 -0.01-µF, 500-1000-WVDC, circuit ceramic-disc Qi, Q2-2N3904 general-purpóse' NPN silicon transistor ADDITIONAL PARTS AND Q3 -2N3906 general-purpose PNP MATERIALS silicon transistor B1 -9-volt transistor-radio battery Sl-SPST slide switch RESISTORS J1-33-See text Printed -circuit materials, (All fixed resistors are 1/4 -watt, 5%1 enclosure units.) (Radio Shack #270-222), molded R1 -47,000 -ohm AC power plug with line cord, 9- R2 -4700 -ohm volt.battery holder and connector, R3 -1000 -ohm wire, solder, hardware, etc., ' J R4, R5 -10,000 -ohm Note: The circuit board and all of the R6 -47 -ohm parts that mount on it are available jam --11/4 INCHES for $14.95, plus $1.00 shipping CAPACITORS and handling from: Krystal Kits, Fig. 2. The author's prototype of the cir- C1- O,068 -µF, 100 -volt Mylar P.O. Box 445, Bentonville, AR cuit was assembled on a printed-circuit 16-WVDC, electrolytic 72,712. Arkansas residents please board, the template for that printed -cir- C3, C4-47 IF, 16-WVDC, add appropriate sales tax. cuit layout is shown here full size.

PL1 using hook-up wire, connect the J3 switch and the three jacks to the ---R5- COM. cir- -C1- cuit board at the appropriate points. -R2- C6 Once that is done, mount an AC 81 C4 J1 plug with line cord to one end of the 4_1 U1 ----IF-- OPEN enclosure. That can be LOOP accomplished Si C2 by first R3 + C5 passing the plug's line cord the -+C3 02 J2 through a 1/a -inch hole in one end of o o o- -R4- -R6 -CLOSED the enclosure, and then clipping off LOOP the 117 excess cord length and con- Fig. 3. Follow this parts -placement diagram when assembling McTrak's printed -circuit necting the line cord to the circuit board. As usual, start with the passive components, followed by the semiconductors, board as shown in Fig. 3. After that is double-checking the.part's location and orientation as it is installed. done, the plug can be secured to the enclosure using hot-melt glue. After all -of the on -board compo- When you are satisfied that the circuit nents have been installed, check your board contains no errors (of the Check Out and Use. To check the work for potential problems-solder nature usually associated with hob- operation of the McTrak, first install a 46 bridges, cold solder joints, and so on. byist projects), place the board to the (Continued on page 98)

AmericanRadioHistory.Com i I1;1;4;11

Ír. h _ ~ Isily -`w^`+ ,

By monitoring the VHF low -band for skip, you could easily make some wonderful long-distance contacts.

BY LAURA QUARANTIELLO

The transmissions were weak, short distance before it becomes ab- ceive VHF skip transmissions. In fact, scratchy and, more often than sorbed by the Earth, but the sky wave any scanner that will search the range not, lost behind the other is much more resilient and that's the of 30-50 MHz will do nicely. Having a voices on the frequency. I'd been lis- wave low -band, distant-transmission search feature is important, because tening to 33.7 MHz for two days now listeners tune -in to. you'll definitely want to program -in and still had failed to hear any infor- The sky wave travels on its merry short ranges of frequencies and let mation that would help me to identify way, high up into the wild blue yonder, the scanner do the work. the station speaking. It had become a until it encounters the ionosphere. An outdoor antenna is not man- minor obsession over the past couple That layer of the Earth's atmosphere, datory, but it will improve your of hours to positively identify the dis- some 150 to 200 miles high, is con- chances of hearing transmissions ten- tant fire -department dispatches. stantly bombarded by the Sun, which fold. A good all -band ground -plane Unfortunately, given the changing charges the ionized gases of the antenna does nicely, but a beam an- nature of the atmosphere, it was likely ionosphere. When a sky wave hits that tenna can have advantages if you

that when I woke up the next morning layer of charged gas, it is partially re- are searching for transmissions from a and turned on the radio, 33.7 MHz flected. Some of the part of the wave specific direction. Since the prevailing would be silent and the transmissions that is not reflected is absorbed by the atmospheric conditions have the gone. To understand how.a long-dis- gas, and the remainder flies into most'to do with reception, whatever tance transmission can appear and deep space. The portion that is re- you use should pull in some signals, so disappear like that, we'll have to do a flected returns to Earth at an angle, give it a try. quick study of radio -wave propaga- which means that it comes down Frequency guides are a great re- tion-the near magic of what hap- many thousands of miles from its point source if you're serious about identify- pens to a radio wave once it heads of origin. That phenomenon is known ing the stations heard. For example, a off into the atmosphere. as "skip." complete set of Police Call maga- Skip is almost a mystical thing, af- zine's frequency directories is invalu- One Little Wave. When a radio sig- fected by sunspots, weather, and able for tracking down domestic nal or wave leaves the antenna of a even the time of year. It can also be a public -safety stations. For military sta- transmitter, it becomes, in theory, two scanner enthusiast's best friend if you tions, try a federal frequency directory distinct parts: a ground wave that know how to take advantage of it. such as Tom Kneitel's Top Secret Regis- travels along the surface of the Earth try of US Government Frequencies. A and a sky wave that travels out into Equipment. You don't need a con- good map book of the United States is the sky. The ground wave travels a trol room full of radios in order to re- also handy. 47 .

AmericanRadioHistory.Com cations activity all across the low band from American and foreign troops in Saudi Arabia. Voices from irmar,00 Central American stations, Panama, j1.Nv yoo t/ Honduras, and the Dominican Re- public are regularly heard engaged in US military operations. Furthermore, lots of counter -drug missions take place on the low band, as well as a _ ' large amount of fire communications. SAN DIEGO FORT BRAGG, NC Fish and Wildlife officers, whose ac-' _v 38.900 tivities often take them far from nor-

1591rn . . mal radio range, can often be heard DX talking on frequencies between 31 CATCHES iJ.-STATE OF LOUISIANA FWS and 32 MHz. 31.060

Identifying Stations. The first order Fig. 1. As you can tell from these catches logged by the author, skip can really help you of business when you come across an pull -in transmissions from all over the country. active frequency is to take down some of the information you hear Finding Skip. Frequencies on the to scan between these two values. coming across the speaker. Call signs, low band -30 to 50 MHz-are most This is about as low as typical scanners place names, and unit ID's are all affected by skip because of their long will receive and is a good place to helpful. More than once I've tracked wavelengths. Frequencies on the start, Here you'll come across business down a frequency user by tracing city higher VHF bands tend to skip less. I communications, forestry reports, names through a map book. don't consider 50 MHz the absolute power and water utilities, and some Here's an example: say, 42.12 MHz is top of the possible skip range. Occa- public safety and military communi- active with a dispatcher calling her- sional forays above 50 MHz have net- cations. If you find active distant sta- self "San Diego." Looking up San Di- ted some interesting catches, but for tions here, work progressively higher. ego in a map book will reveal a the best results, "go low." On some days only a small swath of California location. Drag out volume Searching through the basement of frequencies will be affected, and on nine of Police Call, check all the li- the VHF band, your chances improve others you won't know where to tune censes under 42.12 MHz and you'll drastically. On a good day, it isn't un- first because of all the activity. find a listing for the California Highway usual to hear communications from The region between 31 and 33 MHz Patrol San Diego Office, . thousands of miles away, sometimes is a super place to look for military Military stations can be difficult if even from Central America, Canada, communications, as are the 38-39 call signs such as "Alpha Six Echo" are or overseas. The key to hearing all this MHz and 40-42 MHz areas. Fire de- used, but if you listen long enough you is knowing when and where to listen. partments can be found primarily be- might hear the base name or a unit Since skip is affected primarily by tween '33-35 and 37-38 Mhz. number. When that happens, check a the actions of the sun, it almost goes Highway patrol, a good target for be- federal frequency book for active sta- without saying that daytime is the best ginners, can be found operating be- tions on the frequency to get you time to listen. Try between 9 A.M. and 7 tween 42-43 MHz. These ranges will closer to a positive ID. P.M., or whenever local dusk occurs. If get you started, Take a look at the you're shortwave equipped, listen at back of an issue of Police Call for their DX'ing Low Band: Searching for dis- 18 minutes past each hour for propa- Consolidated Frequency List, which tant signals (DX'ing) can be an en gation reports from WWV on 2.5, 5, 10, will further guide you. grossing, frustrating, exciting, and 15, or 20 MHz. The solar flux number Don't be afraid to experiment and highly variable hobby.

they give reflects the amount of seek ranges the for I beyond norm skip. As predicted, the 33.7 -MHz signal I ionization of the ionosphere's F2 layer, I frequently scan from 49.0 to 49.7 mentioned did fade away by the time and so the possibility of picking up MHz, just below the cordless tele- I listened again the next morning. It long-distance transmissions. phone/baby mónitor band, which was three weeks before I finally heard I target specific frequencies, which I yields up such catches as military - the signal strong enough to warrant. check for communications. For in- range communications (like Camp some serious listening. With a little _stance, 38.9 MHz is a popular military Pendleton, California at 49.0 MHz), more attention I had my catch in no range -control frequency that I have and tactical operations (such as Army time: Jefferson Township Fire Depart- programmed into my regular scan Explosives Ordnance Disposal on. 49.7 ment, Ohio. bank. If I hear communications on this and 49.8 MHz). You never know what If local communications are get- ro channel, I know that skip is present you'll find: I occasionally even hear ting too routine and you'd like to ex- and set-up search ranges to see what live horse -race announcements on plore how other services across the á other frequencies might be active. 41.725 MHz. country handle their communica- Try programming in the range from During the Gulf War, scanner tions, "go loW' and give low -band skip 48 30.0 to 31.0 MHz and set your scanner monitors reported heavy communi- monitoring a try,

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word defeats, glossary much morel Manuals der, over any length of time, whether busy or ' + Disk s' $39. answered (your choice) and log the times, LASER DIODES ' commands and results to monitor, printer , BEYOND' VAN and- ECK PHREAKING or disk. Ouick-dial directory of up to 600 num- LASER POWER SUPPLIES Eavesdropping on GUT and ' V video signals bers. BUSY radial options. Direct modem com- using an ordinary TVI Documented in security mand and control. All Result Codes. including industry literature. Range up to 1KM. Plans in- VOICE and RINGING. Optional shell to termi- -- t, dude both the CONSUMERTRONICS and the nal program upon CONNECT. Exit to menu or --1-r original TOP SECRET VAN ECK designs) $29. DOS (tor batching). Manual + Disk' 529. ) \ \\ CRYPTANALYSIS _TECHN IOU ES 5OFTWARETROTECTION:-S F `t4 . -ive powerful meñu-driven crypto programs (in Unique system that highly discourages costly ° .COM and their. -BAS sources) to analyze, de- software piracy while not interfering with legit -- , crypt 'secure- ciphertexts. Worked -out ex- archival copies. No known way to defeat. No -' /. amples. /+ Recommended In prestigious COM- special equipment required. Simple and auto- ` ;;;/,i ' PUTERS & SECURITY. Manual + Disk' $29. matic to install on your distributed software. ABSOLUTE COMPUTER SECURITY Compatible with all other copy -prevention sys- LASER terns. Manual + 559. USES: Dozens of simple, versatile, secure methods Disk' and,tips. Plus our invulnerable Cipher Pro- i5h ET &SURVIVAL RADIO ° HOLOGRAPHY * LIGHTSHOWS gram (in .COM and its .BAS source). Plus Optimum survival and security radio equip- $1.000 CIPHER COfJTESI ciphertext and ment,methods, Iraq allocations and voice/data ° PRINTING * COMMUNICATION rules. Manual + Disk' $24. scrambling/encoding. Includes small receivers/ transmitters, telemetry. antenna optimizations, - HARD 1DRIVE,MANUAL remote monitoring and control, security, sur- WEAPON SIGHTS * ALIGNMENT 'overs all hard drive ana controller implemen- veillance, and ultrasonic, liberoptic and infrared t tations (emphasis on PCs). How to select, in- commo. 70+ circuit plans, tables. terlace, initialize; set up, use, maintain, trou- 529. ALARMS * POINTERS bleshoot and repair them. How to them protect STEALTH TECHNOLOGY. °, - from mistakes, sabotage, prying eyes and Police radar is fascinating! It also has error How to CUTTING * CONSTRUCTION sticky fingers. recover damaged and rates of 10.20%1 Every known error mode - - lost files. How to prevent crashes to begin with. stealth method and material used to minimize Includes software reviews. Loaded with infor- radar reflections - tactic and strategy to fight mation, advice, lips. 529. - unjust radar tickets (that asst you 5100s in in- FREE CATALOG 1-800-356-7714 DISK SERVICEr MANUAL surance and risk cancellation) - methods to de tect - fully Maintain, troubleshoot, repair, adjust, align and jam signals described) 529.. floppies Without special equipment or software. ROCKETS- RED 'GLARE - INDUSTRIES EB 3.5 /5.25'/8', PC/XT/AT/386/486, Apple, Row to design and build solid-propeliant ama- '' Commodore, etc systems. All floppies need teur and survival rockets. Emphasis on formu- regular upkeep. 529. DISK DRIVE TUTORIAL 198 LEWIS' COURT lation, manufacture, installation of propellants, Theory, practical facts on fldppy drives, disks, motors, igniters, etc. Includes fist of commonly , CORONA, CA 91720 including many tips, recommendations, format- available materials, and the design of launch ting, interfacing, FDC. etc. 519. Both S39. ads and test beds and their electronics. 529. CIRCLE 27 ON FREE INFORMATION CARD CIRCLE 28 ON FREE INFORMATION CARD AmericanRadioHistory.Com ELECTRONICa,.d._ PRDUC'TS and KITS .

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Staring horn scratch you bold a complete computer system Our Micro -Master boner teaches you (Catalog requests can not be taken on toll Measures approx 1 12W x 1 114'04 7/8'H. $4.00 to write Into RAMs, ROMs and run a 8085 microprocessor. You will orne the initial instructions to free number.) tell the 8085 processor to gei started and store these instructions in permanent memory m a 2816 Mdsl E PROM. Teaches you al about Input and output ports, corrpuler turner. Budd your own keyboard 8 a.m. - 5 p.m. EST 200µA movement. Scale and learn how to scan keyboard and display. No precious computer knowledge required. Staple reads both signal (030db) and 91 easy to understand nstNdlon teaches you to write in machine language. Upon completion of Ins Monday through Friday SWR Same mounting as above. course you will be proficient in computer technology. Measures 1 x 1 1/4"D x 3/41-1. Cd 31&W $4.00 Uses the 8085 Microprocessor OR WRITE TO: °MP Uses the 2816 E PROM, electricaayerasable Ocean State Electronics, programmable ROM MULTIVOLTAGE RECTIFIER DIODES Uses the 81560, 2048 Bit static MOS RAM P.O. Box 1458, Westerly, R.I. 02891 with VQ pons and timer AC ADAPTER 1N4001 .09 L-. Rated SOVOA 0.1.09 Memory expandable option OR FAX TO: CATALOG REQUESTS M Bun in 5V power Input 117VAC supply 1N4003 .10 28 ley keyboard (401) 596-3590 (401) 596-3080 Output 3V, 4.5V, 6V. d CorrpetewM lesson manual, lnstruduorló and 7.5V, 9V, 12V DC 1N4004 .10 expenments If paying by CREDIT CARD include Card No. Polanty switch 1N4005 .12 Universal plug 1N4006 .15 and Expiration Date LO ' 1N4007 .17 Mail W $119.95 in orders please include $4.00 shipping 1N5400 .20 CANADA $7.00 - OVERSEAS $12.00 1N5401 .20 o Minimum order $10.00 1N5402 .20 0 1N5404 .25 -yy cIrcultTm works NEW MICRO TIP R. I. Residents add 7e/e Sales Tax 1N5406 .25 CONDUCTIVE PEN FOR THINNER TRACE ORDERS RECEIVED BY PM EST 1N5407 .25 m 1:00 - $5.95 Use where conductive electronic: traces are needed 1N5408 .25 ñ For designing Prototype circuits SHIP SAME DAY! Pen tip redesigned to draw more narrow traces FREE SHIPPING ON ALL MAIL IN ORDERS Offers Improved conductivity, better trace adhesion, and a reduced settling in the pen COPPER CLAD g. Dries in 3-5 minutes el room temperature OVER $25.00. PC BOARDS Spring loaded tip for smooth flow NOT VALID WHEN COMBINED W/CAT. ORDERS. One oz. copper. phenolic base. Applies to UPS Ground in Continental U.S. Only. Single sided 7 x 5 $1.50 $10.95 PRICES SUBJECT TO CHANGE 50Q 8'x7 $2.00

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1. Put Ribbon into your printer. 2. Print message or design onto regular paper but print it in a mirror image. (Print CABLE TV Shop and other programs have this capability.) "BULLET" BUSTER. Protect your cable box 3. Place paper lace down on T-shirt and kan the back of paper to transfer the image. against the infamous "bullet." The "Bullet" Buster acts as an electronic shield. Installs in -line in sec- Available in red, green. blue, or black at onds. Don't wait until it's too late! $19.95 plus $9.95 each for the following printers Dept. RE, PO Box (specify make and colors wanted). $3.00 S&H. ELECTROMAN, Panasonic 1080/1180/1090/1190/1123/1124; 24474, New Orleans, LA 70184. IBM Proprinter; Epson MX)FX/F)(80/85/86e/ Lx800/10500/L0510/L0570/L1000; Star SELECT THE WATTAGE TOCOM MAPPER chip. Align those channels! N X/N IJ N P 10/ N X2400241012415/2420/ One chip - no soldering 20 $110.00 ppd. UPS LC24102415; Seikosha SP800/1000. Tandy COD. Jerrold Starcom remotes SCR II 20 @ DMP130, Epson AP80, Apple Imagewriter; YOU NEED to 1000W -200W + Call Apex, (414) 554-8618 Citizen 12ODi180D/GSX140: okideta 182/ $6.50 ship. Stan - 192/320/390. Perfect for Campers or Emergencies phone -fax. Also for sale cable encoders. SA, Jer- of Plans rold. $10.95 each for Epson MX/FX-100286e, Send $29.95 for Complete Set LO 1000/1050, L025002550/EX800/1000/ & Theory of Operation to L0860 $4.95 each for Okidata 82/92/83/93/ Gemini 10X/15X.

° INVERTER SCIENTIFIC Available in BLACK only at $9.95 each for COMPUTER EQUIPMENT Panasonic 1625/1525. Star NX1000, NEC -° Box 778, Suffern, N.Y. 10901, WANTED P2200, Commodore MPS -601. TEACHER WANTS Tandy color computer junk! Available in 4 Color Heal Transfer for Image - writer II $11.95; Star NX1000 $14.95; Charles Scanlon, 2 Eagle, Simsbury, CT 06070. Star NX1020 $2195: Star N02420 Keep trying! (203) 657-8373. $23.95; Citizen GSX140 $23.95; Epson L02500.2550 $14.95; Fujitsu DX210 / 22002300/DL3300/340073600 $27.95. HEAT TRANSFER MARKING PENS Add colors to the computerized design or II§ use alone. Set/5 Colors (red, orange, yellow, BUSINESS OPPORTUNITIES green, blue) wide pens $15.00, narrow I You Need pens $14.00. CASH FOR TRASH. Hams/hobbyists turn electronic scrap into CASH. Extra money or start a HARD -TO -GET Tree City USA new career. VHS video shows all, $19.95 plus PRINTER RIBBONS $3.00 S&H. LYNN JOHNSON, Box 51268, San Oyer 200 different nbbols in stock All ribbons Jose, CA 95151-1268. new, not re -inked. Fully guaranteed. Order City trees add the directly or send SASE kX complete list. soft touch of nature Add 52.00 p., order alppng C.aa,ns residonl. add 7.75% sobs lax On nbbun Orden oven $3000 d.dud to our busy lives. l0% discount Support Tree City PUBLICATIONS H.T.ORR USA where you live. MARCONI SALAD and Tesla Taters! Elec- just in time for Computer Supplies For your free booklet, troMeals Cookbook, available 249 Juanita Way, Placentia, CA 92670 holiday gift giving. The perfect present for the write: Tree City USA, Ham's mate. 125+ recipes, $12.00 plus $3.00 Dept PE, Box 24474, New VISA" The National Arbor Day S&H. ELECTROMAN, Orleans, LA 70184. Foundation, Nebraska 714-528-9822 City, NE 68410. ®The National 800-377-2023. Arbor Day Foundation FAX 714-993-6216 ' ../

PCB ARTWORK $4 9 bccwo s üzñ¿" /---,- =_'a=:?''`. Four C. &AC. PEEinnrtin. MADE EASY! motor KC- KC- 'Are you tired of laying down tape or wire wrapping to make printed circuit art? kit with computer interface End the nightmare with the PCBoards CircuitLayout Program forjust$99.00! Easily create single or double-sided circuit boards with professional results.

Here, CGA, EGA, VGA, & SuperVGA Copper flood for building ground planes High speed and/or keyboard Block move, copy, rotate, save, etc. Use mouse Closed loop Galvo kit Squares Built-in help screens Comes with dot-matrix & laser output to 180 hz, & Circles to 900 hz Dip and Sip footprint libraries Make your own films with lx laser art Build custom parts easily Gerber and Excellon output available Requirements: DOS 3.0 or later, 1 disk drive, 384k of RAM, IBM-PC or compalible FREE Download Demos from our 24hr BBS at (205) 933-2954 catalog of Kits PCBoards Software Prices: Add on Software: PCBoards Layout 99.00 PCRoute Autorouter 99.00 Silicon Valley Surplus Gerber and Excellon Drivers 49.00 PCRoute+ Autorouter 149.00 1273 Industrial Prkwy West Plotter Drivers 49.00 SuperCAD Schematic 99.00 Bldg 460 Demo Package (all software) 10.00 SuperCAD+ Schematic 199.00 Hayward, Ca .94544-7025 Use PCBóards, PCRoute. and SuperCAD as a "system" to create pcb art froth a schematic! 510-582-6602 PCBoarde -2110 14th Avenue South, Birmingham, AL 35205 / Ph. (800)473-PCBS Fax (205)933-2954

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AmericanRadioHistory.Com ADJUSTABLE REGULATED POWER SUPPLY 2 -28 VDC at lA continuous MUMBLEY BEAR 1% regulation. 12" Tall Teddy Bear $69.95 each Talk and it imitates your voice in "bear talk." Soft and cuddly. I $19.95 each BREVEL °"; '_ ROBOT PUPPY DC GEAR '- A fun canine with an internal microprocessor control system is a marvel of state of the art technology, fea- MOTOR / turi ng DUAL DC DRIVE MOTORS with GEAR RE- 24 to 130 RPM, reversible, 12V to 120VDC with ther- DUCTION and two-inch diameter RUBBER TREAD mal overload, 0.375" shaft x 2.25" long. DRIVEWHFR1 S that provide excellent mobility and BIG RED $19.95 each traction. Special integrated sound analysis and recog- 4x4 TRUCK nition circuitry allow you to command your Robot Radi o control led (2 channel), 120x 8.0 cm pneumatic Puppy with simple hand claps. When your Robot rubber tires, range up to 100 ft., removable camper Puppy hears your commands, it moves, whines and shell, climbs 40°45° angle, dual proportional radio barks, and its eyes light up! If you ignore it, it will "go control, dual speeds, recharging jack, full power to all '1,1,0,1,41.: TRANSFORMER to sleep" and then awaken at your command. Original 4 wheels, reinforced front bumper, fun for all ages.

. 12 VAC, lA, with power retail price over $100.00! $29.95 This is not a cheap toy! $49.95 cord and secondary wires. $4.95 each PRECISI ON SCANNER AUTOMOTIVE OBJECTIVE PACKAGE POWER CORD LENS 386 DX 20 MHz system, 3 Room for fuse inside heavy- 21mm f:3.5. Four coated glass MB RAM" 360K 5.25" floppy, 201%/113 hard drive, Hercules -compatible mono duty plug. 6"cord included .xñ,. lenses in black aluminum case $1.49 measuring 1-5/32' long by 1-1/ monitor. Canon flatbed scanner with JLaser AT -3 interface, drivers and software. $899.00 16" diameter. Excellent conec- , . tión of all aberration for an angle CANON FULL PAGE of 35° without vignetting (obstruction of view at Y COLLINS DESKTOP SCANNER edge), or 45° angle with slight vignetting. Linear PRECISION 300 x 300 DPI. With I/O card. cable, software and resolution in focus is very near the theoretical limit of documentation. $349.95 CRYSTAL 385 lines/mm when the image of object is in focus CONTROLLED (D=6mm), or 500 lines/mm when object is in focus WE BUILD OSCILLATOR (numerical aperature=1.41): Possible applications CUSTOM 100 KHz and 500 KHz outputs. Diagrams included. include: objective lens for scanners; photographic ob- SYSTEMS! $12.95 each jective enlarging linearly 10X; objective for a handheld microscope, enlarging 'from 30X to 120X Call or Fax (numerical aperature=1.41); lens working with light for price sensor or emitter as a precise focusing element; or lens quote. for shaping a laser beam. $12.50 ' DTS413 NPN SILICON TRANSISTOR 3 -BUTTON Similar to NTE162 Commonly used in TV vertical MOUSE deflection. 500V, 1A. For PC's and compatibles. $2.00 each -12 for $10.00 Microsoft and MouseSys- tems compatible., 350-700 E: DPI dynamic resolution. BARE BONES SYSTEM ° i thsoftware and instruc- 4 MB EPROM W XT type motherboard with 8 slots, slide -in cabinet, tions $14.95 each power sypply, 256K RAM, upgraded BIOS, NEC V - Brand newt Toshiba No. 20 CPU. Expandable. New. Accessories and up- TC574000D-150. grades are available. Call or FAX for quote. oni tor $37.95 each AT RLL DRIVE CONTROLLER 2 hard drives, 4 floppies. $19.95 and keyboard not included.) 9.95 1200 BAUD INTERNAL MODEM IDE CONTROLLER.CARD 27C512 EPROM For PC's and compatibles. With software. Erase and save! JP3: HDD LED. JP1: FDC enable/disable. JP2: HDC $19.95 each $1.99 each enable/disable. J3: I/O channel ready. $14.95

MINICIRCUITS LABORATORIES xerr'i`. PRODUCTS PSC2-1 10.95 PHILMORE PSC3-1 20.50 ANTENNA KIT PSC3-1W 32.00 14" MONITOR For improved broadcast and PSCQ-2-50 18.00 Brand new, boxed, open frame hi -res TTL mono- shortwave reception. The per- PSCQ-2-180 18.00 chrome moni tor. Standard pin -out. Diagrams for power fect starter antenna $7.95 SRA-1 10.00 supply and connections included. $14.95

Also visit: Retail Store Hours: ASCII Electronics M -F9-6 1020 Marietta Way Sat. 10-3 Sparks, NV 89431 ALLTRONICS (702) 355-8822 2300 Zanker Road San Jose, CA 95131 VISA- MC - AMEX cards accepted. Minimum order $15.00. California residents add 8.25% sales tax. Shipping additional on all orders.

020193 Phone (4081 943-9773 Fax (408) 943.9776 50S CIRCLE 26 ON FREE INFORMATION CARD

AmericanRadioHistory.Com GRABS SIGNALS 'A:CALLE.R COM:PUTÉ R CHEAP SOFTWARE FROM PHONE LINE nterface;. SAVES CALLS

INCOMING CALL IM PC-620SW IBM-PC SOFTWRE 09/1 5 10:35 (805) 389-1270 Z PHONE LINE WITH RS -232 TO SERIAL "CALLER I.D.' SERVICE (ALSO SAVES EACH CALL TO DISK) I COM PORT

THIS PRODUCT WILL NOT WORK IN ALL AREAS YET. YOU MUST HAVE YOU'VE HEARD ABOUT THEM "CALLER I.D." SERVICE (FROM YOUR LOCAL PHONE COMPANY). WE'VE GOT THEM HERE I BOOS TER FOR MINIATURE TRANS MITTER, S CONVERTER - PHONE UNE IN / RS -232 OUT. INCL3-FT PHONE BOOKLET - 56 PAGES: THEORY, RF POWER AMP BOOSTS 88-108Mhz MINIATURE FM TRANSMITTERS' RANGE - I PLUG, 3 -FT RS232 CABLE, SCHEMATIC PARTS GUARANTEED AND UST MESSAGE -TYPES W/EXAM PLES - INCL COMPLETE KIT W/SCHEMATICS 1MPC-RE2 $26.30 IMPC-620 $59.00 IMPC-BK S19.50 (W/PURCH OVER $20 $14.50) E-Z TUNE (25 TURN) STABLE HI-FI FM MIC - SURF. MNT "STRIPPED' VERSION, BRAND NEW BUT SLIGHTLY OLDER (MEDIUM RANGE, SUPER SENSITIVE) IMPC-RM5 $44.00 DESIGN, NO COVER, NO RS-232 CONN- HOOD. PERFORMS CHECKSUM CALCS. LONG RANGE FM MIC - SMALL BUT VERY POWERrUL V SO., NON -SURFACE -MOUNT KIT IMPC-RM52 EQUALLY WELL AS NEWER DESIGN. TESTED, SCHEM. AND ALL NAME DELJVERY' $38.D0 CABLES INCL. - BARGAIN. ' IMPC-320 $48.00 INCLUDES TOUCH TONE DECODER DISPLAYS PHONE NUMBERS AS HEARD FROM RADIO TAPE OR PHONE LINE. SCHEM. FOR 3 BUILT-IN 200 ,DIGIT MEMORY IMPC-TDD 5168 "KIT' VERSION - ALL SURFACE MOUNT PRE-ASSEMBLED. SPEND DECODERS 15 MINUTES SOLDERING CABLESAND SS IMPC-320K S42.00 SAVE ANDA CALLER International MicroPower Inc. 65 Palm Drive YOU MUST RUN SOFTWARE (YOURS OR OURS) TO GET SERIAL I.D. Camarillo, CA 93010 +$3.SOS.H. GENERATOR DATA TO THE SCREEN AND DISK FILE. OUR POP-UP WINDOW 1--805-389-1270 (S7.001F TSR' SOFTWARE FOR IBM -COMPATIBLES IMPC-620SW $7.50 (REO 1200 MC or VISA Accepted CA residents add Sales Tax

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AmericanRadioHistory.Com Dial 317 849 8683 to get instant tech information FREE from your Fax! You can obtain specs and info on these products and more by dialing our Fax Facts automated service. Call our number from your fax, then request the cocument as listed 800 445 7717 below. Start your fax and the document will start printing immediately on your fax! 317 842 7115 =COMMUNICATIONS-- [Mobile Scanners [ Hand Held Scanners ACE Communications Monitor Division ,,,.^. a, xew?^7,,..,r.. T,,, , , s..a. ; 10707 East 106th Street Fishers, IN 46038 Bearcat AOR 900 $199.95 [Scanner & Shortwave 760XLTM 100 Channel 800 MHz $249.95 Five scan banks 5 search hanks. Covers 29-54, 118- 100 Channel 174,406-512 and 830-950 AOR AR1000XLT 800 MHz MHz (no cell lock). Features scan, search, delay, Five banks of 20 channels each. Covers 29-54, $429.00 priority, permanent memory, lockout, backlite, & 118-174, 406-512 and 806-954MHz (with cell AM keylock. Includes AC/DC adaptor, belt clip, Broadcast to lock). Features scan, search, delay, priority, Microwave antennas. Size: 5 3/4H x 2W x 1 1/2D. Wt: memory backup, lockout, service search, & 12oz.. Fax fact document #650. 1000 Channels keylock. Includes AC/DC cords, mtng brkt, antenna. Size: 4 3/8 x 6 15/16 x 1 5/8. Wt: 500KHz to 1300MHz coverage in a 4.51bs. Fax fact document #550. Bearcat 200XLTN programmable hand held. Ten scan banks, ten $219.95 800MHz search banks. Lockout on search and scan. AM Bearcat 2000~ plus narrow and broadcast FM. Priority, hold, Ten scan banks plus search. Covers 590XLTX :. .---- IBAit, delay and selectable search increment of 5 to 995 29-54, 118-174, 406-512 and 806 - .ay:ugaw KHz. Permanent memory. 4 AA ni -cads and $199.95 I_ ,--.- 956MHz (with cell lock). Features, wall plus cig charger included along with belt 100 Channel . scan, search, delay, 10 priorities, mem backup, lockout, WX search, & clip, case, ant. & earphone. Size: 6 7/8 x 1 3/4 x 11 Band 2 1/2. Wt 12 oz. Fax fact document # 205. Five banks of 20 channels each. Covers 29-54, keylock. Includes NiCad & Chrgr. Size: 1 3/8 x 2 118-174, and 406-512MHz. Features scan, 11/16 x 7 1/2. Wt. 32 oz. Fax Facts # 450 AR2500 search, delay, priority, memory backup, lockout, Bearcat 100XL'INNow$159.95 service search, & keylock. Includes AC/DC $399.00 100 Channels, Keybomd Programmable. cords, mtng brld, antenna. Size: 7 3/8 x 6 15/16 x Scalar to 20]XLII4 above wkhout 803ts4Hz. Fax facts 9460 2016 Channels 1 5/8. Wt: 4.11bs. Fax fact document 4570. 1 to 1300MHz Bearcat 70XLTP Only $139.95 Computer C lad Bearcat 20 Channels Keyboard Programmable. 560XLTZ 10 Band Hand Held with Ni -Cads & Charger. Fax facts 9470 62 Scan Banks, 16 Search Banks, 35 Channels $99.95 Bearcat 55XLTR Now $99.95! per second. Computer control for logging and 16 Channel 10 Channels Keyboard Programmable. spectrum display. AM, NFM, WFM, & BFO for 10 Band CW/SSB. Priority bank, delay/hold and selectable search increments. Permanent memory. Compact, digital programmable unit covers 29- [ 54, 136-174, and scan, Table Top Scanners DC or AC with adaptors. Mtng Britt & Antenna 406-512MHz. Features WX search, delay, priority, memory backup, included. Size: 2 1/4H x 5 5/8W x 6 1/2D. Wt. lockout, review,& auto delay. Includes AC/DC Bearcat 855XL'IENow$179.95! 11b. Fax fact # 305 50 Charnels Keyboard Programmable with 800MHz. LCD cords, mtng brkt, antenna. Size: 7 3/8 x 2 1/2 x 1 display, lock, priority, Search, WX, Fax facts 9655 5/8. Wt: 2.5lbs. Fax fact document #560. AR3000 Bearcat 142XLM Only $87.95 $1095.00 Trident ooóoódoo 16 Channels with 10 bands. LED display, lockout, priority, WX 400 Channels F- A scan , review key and memory backup. Fax facts 9660. Tit-2C * T T 0_ 100KHz to 2036MHz Q000caoo ! Bearcat 147XLJ Now $89.95 $89.95 16 Channels with 10 banda. Track tuned, LED display, priority, Scan/CB WX search, review, memory backup. Fax facts 9670. Extreme coverage, excellent sensitivity, plus with optional laser detector processor controlled band pass filtering and Scans pre-programmed by state channels in low, Bearcat 172XLM Only $124.95 high, UHF & T bands. Weather, 40 ch. CB attenuation to eliminate interference. Top rated 16 Channels with 10 bands. Track toned, LED display, priority, receiver in its class, offers AM, NFM Wide FM, receive plus mobile relay. Size: 5 5/8 x 4 7/8 x 1 WX search, -eview, memory backup. Fax facts 9680. LSB, USB, CW modes. RS232 control. Lockout 3/4. Wt: 1.5Ibs. Fax fact document #580. in search. 4 priority channels. Delay & hold & Mag Mount Antenna. Easy to install whip antenna with 20 Bearcat Freescan modes. AC/DC pwr cord and whip ant. of coax & heavy duty magnet BNC MA 100 $19.95 Base Antenna 25 to 1000MHz coverage with 50 of coax. 800XLX included. Size: 3 1/7H x 5 2/5W x 7 7/8D. Wt All mounting hardware included. BNC AS 300 $59.95 $239.95 2lbs., 10oz. Fax fact document #I05. External Speaker. Base or mobile mount. MS190 519.50 Wkle Band Pre -Amp. Variable pin up to 20dB coven 100 Free Stuff KHz to 1500MHz. 9Vban included. BNC. GW.2 $89.00 12 bands and 40 channels with 800MHz and Demo disk of SCS (scanner Interference Filter. Filter and eliminates ~ow causes of nothing cut out. AC or DC. Fax facts #690. control system) software for AR interference to sca®en. BNC. Model MP[F-l. $59.00 3000 & AR2.500. Call toll free Downconverter. Converts 800MHz frets to 403Miz for 3 band scanners. Quartz locked, 9V ban. DC89. $89.00 2 to order. Also, Free with AR2500: Control Way Radios Extended Warranties & Service. Extended warranties software, a $49.95 value. Allocation chart of all available for most models. Call for quote. Out of warranty VHF hi band programmable mobiles as low as voice frequencies. Dial Fax Facts for doc. #999. service by ex- Bearat/Regency factory echo. Cal: for quote. $299.95. Call for quotes or Fax Fact #755

Call Toll Free, 24 Hours a Day! Dial 1-800-445-7717. Fax Toll Free, 1-800-448-1084 800 numbers operational in all 50 states, plus Canada. For international voice lines, dial 317-842-7115 or fax 317-849-8794 ACE Communications 10707 East 106th Street, Fishers, IN 46038

Service & Support hours: Mon. - Fri. 9 AM. to 6 P.M , Sat 104 EST. MasterCard. Visa, Checks, Approved P.O.1s & C.O.D. (add á5.0Q) & AMEX (add 5%.) Prices, specifications and eseilabiliy stttied to charge Flat rate shipping & handling charge, 64.95 per unit Express shipping available , no express C.O D. One week trial, no returns accepted two weeks after original receipt without substantial restocking charge. All units cany full factory warranty. Indiana residents add sales tax

CIRCLE 35 ON FREE INFORMATION CARD AmericanRadioHistory.Com IN CA I.BOO.521-MARK (orders only) INC OUTSIO« CA 1 -800423 -FIVE (orders only) DC/CAD MARK V ELECTRONICS, OBDEe BY FAO (213) 888.6868 1985 a INFORMATION (213)8B8.89e,9 Competit ve Irl'ices"fact Shipping Since CATALOG introducing...

indicates the level of difficulty in the assembling of our Products. Power Transformer! Special otter will be given to the purchase of Amplifier Metal Cabinet 300W HI-FI POWER AMPLIFIER (MONO) 100W t 100W NEW CLASS A DC STEREO THE TERMINATOR AMP TA -3600 A&, Power output 300 watts RMS PRE AND MAIN watts Super HighDensity Router into 8 ohms. 540 watts music TA -1500 Power output: 80 per & PCB EDITOR) power into 8 ohms Fre- channel into 8 ohms 100 watts (Complete with Scematic quency response: 10Hz to 1e. per channel into 4 ohms Total harmonic dis- Total harmonic distortion: ' 20KHz Features the following powerful algorithm & capability: Less than 0.03% Frequency , tortion: Less than 0.05% I h'-, response: Aux input: 5 to Kit: $85.00 Intermodulation distortion: Rip - up and Retry 50.000 Hz.0.2118.-2dB Fre- Assembled less than 0.05% Sens- Kit: S73.70 response: Power am- 8 Tested: 5110.00 itivity: 1 V rms at 47K Assembled quency Pre -routing of SMT components to Power requirements: 60 to 75 VDC at 8 amp Di- & Tested: $95.81 plilier section: DC 478 Aux: 150 mensions: 8'x7y'x21/4' 20OKHz Sensitivity: Phono: 2.5 mV (ro Real-Time via minimization mV (r, 47K Mic: 6 mV o, 10K Output: Tape: 150 mV 120W MOSFET POWER AMPLIFIER (MONO) o, 47K Preamp: 1V Gr 60C ohms Power trans- Real-Time clean up passes TA -477 T. H. D.: Less Than 0.007% former: 26V to 32V AC x 2 (n 6 A (Mark V Model -.. Power output: 120 watts into ^otrif '1 . x a 001) P.C. Board Dimensions: 10.5 x 6.13 2.25 User defined strategies F, 8 ohms RMS Frequency re- f Heat sink: 5.13 x 2.63 x 3' (Each) Use rack mount --"'`-5 sponse: 8Hz to 20KHz, +0-0.4 as Task cabinet LG 1924 or LG 1925. Window 3.0 capability DOS dB Sensitivity: 1V Power DC STEREO MAIN requirements: 55 VDC O, 3 80W a 80W PURE Kil: , $68.00 1 -mil Autoplacer and Autopanning POWER AMPLIFIER Assembled amps. May use Mark V Model watts á Tested: $85.00 003 Transformer. TA -802 Power output: 80 Two-way Gk .lrc. and DXF per channel into 8 ohms 60W Stereo Power Amplifier 60W Total harmonic dis- Automatic Ground Plane w/ Cross-Hatching input) (with Mic. tortion: Less than 0.05% Frequency response: SM-302 AA* at rated power Complete w/ Schematic & Dolly Libraries ' - 20Hz to 20KHz Total - .. T Intermodulation distor- harmonic distortion: Optional simulation capability & protected mode for 386 users Kil: $45.94 lion: Less than 0.05% at < 0.1% Power output: Kit: $73.00 rated power Frequency 60W per channel into 4 Assembled Assembled & Tested: $59.72 response: DC to *PCB LAYOUT SERVICE AT LOW COST * á Tested: $85.00 ohm load 33W per 200KHz. -0 dB. -3d8. o, 1 watt Power require- channel into 8 ohm load Input sensitivity: Mic ments: 30 VAC x 2 Or 6 amp. May use Mark V model 10mv Ht 380mv Lo 640mv Signal to noise ratio: LEASE PROGRAM & SITE LICENSE AVAILABLE 001 transformer P. C. Board: 8.1/2 x 5' x1-1/8" Heal than 70 dB Power consumption: 100W. Di- Better sink: 5-1/8- x 2-5/8' x 3' (Each) mensions: 360 mm x 75 mm x 200 mm. VIDEO/AUDIO SURROUND SOUND PROCESSOR PROFESSIONAL COLOR LIGHT CONTROLLER SM-333 AAA* Frequency re- SM-328 * sponse: 20Hz to Independent input Az rrllr74 e.. 20KHz Total Han - Mr"ifir signal control monic distortion: Professional styled Kit: $73.00 Front channel: Design control panel I Assembled Rear chan- Computation 4 independent outputs - .- á Tested: $85.00 0.05%. Input signal voltage: 0.1 to 4 Independent dimmer controls net: Less than0.25% 1771 State Highway 34 3.5V Output: Front channel: 0.1 to 3.5V Rear Chaser speed controls Assembled & Farmingdale NJ 07727 channel: 6.6V Delay time: 5 to 50 milliseconds Automatic chaser operation Tested: 5165.00 (9081 681 - 770W (9081 681 - 8733 (FAX) Input impedance: 47K Power requirements: 100-120 4 preset chaser programs VAC. 60Hz Dimensions 14.2 wide. 4.87 deep, 2.1' high. CAD market " Clockwise chaser control " DC/CAD ... The focal point offuture AMP. Anti -clockwise chaser control 120W t 120W AC/DC STEREO HI-FI á PA Match -with any stepdown transformer from SM-720 AA 12 to 24V AC. SPECIFICATIONS SPECIRCAsdNs x OutputP Power: 120W 2 (P.M.P.O.)) sensitivity (music mode): 1000V. music000gramt ( Input Sensitivity: Tape 300 mV Aux 300 mV Phono - 1170W per channel MAX. Also W total ALL THE PARTS 2V Output power 3 mV Mic 3 mV Power requrrements: 105-120V. 60Hz D_mensmns: 8dB Bass o 8dB 14 32' wide. 9' high. 3.19' deep. Tone Control: Treble ± Frequency Response: 20Hz-20KHz Rack Mount Metal Cabinets Power Requirements: AC110/60Hz DC12-16V YOU'LL EVER NEED AT with aluminium panel are Dimensions: 10 -518'4.1/8'x3 -1/8-(W o O x H) suitable Ior many projects and most of our kits. We provide transformers for KII: S75.00I MCM ELECTRONICS of our Mark V ampli- most Assembled +I u1114 -v °-- fier kits. á Tested: $89.001 .:k: t Because needs in the electronics MARK V ELECTRONICS, INC. industry are constantly changing, MCM Electronics continually researches the 1:. Slautioit Ave.. N1on1ebcl10. CA 90840 8019 market and reacts to the market's CIRCLE 29 ON FREE INFORMATION CARD changing needs. sr- MCM is constantly in touch with national and international manufacturers to bring both commonly used and hard - to -find products to its customers. There are over 20,000 items stocked and ready to ship, including: r- Semiconductors, connectors, audio F REE and VCR parts and accessories, television parts, hardware, test equipment, chemicals, tools and many VOLUNTEER TAX a-. name brand items. For A FREE Catalog Call: ASSISTANCE ECEOTeOMICEIl.p 1-800-543-4330 To Order By Fax: 1-513-434-6959 For Product Questions Call: 1-800-424-1040 1 -800 -824 -TECH (8324)

MCM ELECTRONICS ASK FOR SITE NEAREST YOU. 650 CONGRESS PARK OR. CENTERVILLE. OH 45459-4072 J A PREMIER Company POP -02

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Operating voltage: 1.1 to 1.5 kV Piezo Element Operating current: 4 to 5 mA. Recessed ; 20 Amp RFI/EMI 0.250 quick connect terminals for output. r Color coded wire leads for input. CAT S LPS-1 $35.00 each 3 Wire 'Surface mount - Filter Piezo Element. LED chip. D.C. Wall Transformers (120 Vac INPUT) Taiyo Yuden Co. a Corcom x 2066 Clear when off, green when lit. CB35BBKR4. 20 amp RFVEMI volts Amp* Plug aryls Cants' Cale Aloe Very tiny - whole unit is 0.115' purpose Self-excited piezo general 4 Vdc 70 rna 2.5 men co-ax negative DCTX-470 $200 I X 0.055' X 0.05' thick. 1 mm common electric diaphram -mode 6 Vdc 300 ma 2.1 mm co -ax positive DCTX-832 $2.75 (0.04') lens diameter. Gold- 1.40' diameter s thick. filter. Controls 2 8.3 Vdc 10 ma. battery snap DCTX-8310 $1.50 0.021' plated mounting surfaces for Resonant I line to -ground noise. 9 Vdc 300 ma 2.1 mm co -ax positive DCTX-932 $3.00 resistance: 400 ohms. superior conductivity. 5' color -coded leads. Small size, low 12 Vdc 100 ma. 2.1 met co-ax negative DCTX-1210 $250 CATS SAILED -2 10 for CAT* PE -12 $2.1X) leakage. 3.46- X 1.16' XVI( 112 Vdc 500 ma 2.1 inn co-ax negative DCTX-125 $4.50 $1.00 each 100 for $18.00 10 for 100 2.81. UL and CSA listed. Threaded ,12 Vdc 800 ma. 2.5 mm co -ax positive DCTX-1281 $5.25 $8.50. for $65.00 1000 for $140.00 stud terminals on input and output. 12 Vdc 1 Amp none DCTX-121 $6.50 RECHARGEABLE Standard JUMBO CATS RFI-201 $8.50 each 14 Vdc 700 ma. 1.3 mn co -ax negative DCTX-1470 $5.25 Diffused T 1-3/4 size (5 mm) 15 Vdc 400 ma. 2.5 mn co-ax negative DCTX-1540 $4.50 ELECTROL UMINESCENT Gell Cell Batteries iVERY SPECIAL DEA L RADIOSONDE BACKLIGHTS 17 Vdc 210 ma. WALL 12 VOLTS 0 10 AMOURS RED CATS LED -1 WEATHER 10 for $1.50. 100 for $13.00 TRANSFORMERS GREEN CATS LED -2 New 17 Vdc, INFORMATION 10 for $200. 100 for $17.00 210 ma wall TRANSMITTER YELLOW CATS LED -3 transformers. 10 for $2.00 100 for $17.00 6 ft. cord. Viz(r) Radiosonde Unusual A'radiosonde" is REDUCED PRICES co-axial device on end of a weather instrument, usually Two 6 volt 10 AM batteries, FLASHING LED cord can be cut off and used released at high assembled as a single 12 volt W/ built in flashing circuit Al last) A low cost eledroluminesoent for another application. altitudes, do package. Package size: 5volt operation. T 1-3/4 glow strip and inverter. These brand- Large quantity available. - CATS signed to transmit 6' X 3.94' X 3.75" (5mm) new units were designed to backlight DCTX-1721 $1.50 each =11111$ for temperature, CATS GC -1210 $35.00 each small LCD TVs made by the Citizen 100 $1.25 each Watch company. The inverter crcuit 1000 for $1.00 each humidity, winds 12 Volt 2 Amp RED 504 each changes 3 or 6 Vdc to approximately and pressure at CATS LED -4 10 for $4.75 101 Vac, the voltage required to light the 10 AMP SOLID - various heights Transformer GREEN 755 each glawstrip. Luminescent surface area is STATEF1ELA.Y above the ground. CATS LED -4G 10 for $7.00 These are new Same as Mouser 1.7' X 2.25'. The strip is a salmon color in its off state, and glows white when ' (USED) units, discontinued from NOAA Na- S 41 FG020. YELLOW 755 each energized. The circuit board is X 1'. 10 amp tional Weather Service. Contains lots 12 VCT, 2 Amp CATS LED -4Y 10 for $7.00 2.7 Glow strip and circuitry can removed solid state of interesting parts: a solid state trans- power transformer. be LED HOLDER easily from plastic housing. Ideal for relays, removed mitter, barometric pressure sensor, 7 X 2.35' X 210'. 2.90' mount- Two piece holder. special lighting effects. from equipment and tested. humidity sensor and a 24 volt battery ing Pigtail centers. leads. CATS HLED Control voltage: 250 volts AC which is activated when submersed in CATS TX -122A $4.00 each 10 for 655 3 -0 Citizen,/ 92TA operates on 3-6 Vdc al 10 amps. Standard 'hock- water. Great for school science dem- 10 for $37.50 CATS BLU-92 $3.50 each ey -puck' size: 2.27' X 1.72' X onstrations or as a source for parts. CATS WIT -1 each Rechargeable Batteries (nickel -cadmium). LA,WGE OUAN'TTY AVAILABLE 0.95'. UL and CSA listed. $4.75 CATS SSRLY-11U Case of 16 for $64.00 10 for $32.00 100 for $275.00 $8.25 each 10 for $80.00 4 AAA RECHARGEABLE ani Motor Speed Controller And Timer BATTERY PACK (USED) ws ae o. With a minimum of external wiring, AAA 1.20 180 mAh NCB -AAA $1.50 $13.50 this PC board will control the speed Battery pack with 4 AAA AA 1.20 500 mAh NCB -AA $2.00 $18.50 and duration of a 120 Vac motor or nickel -cadmium batteries AA w/ other load up to 300 watts. When in series to make a Solder Tabs 1.20 500 mAh NCBSAA $2.20 $20.00 activated, motor will operate for 10, 4.8 volt pack. Batteries Sub C w/ 20 or 40 minutes or oominuousy at can be separated Solder Tabs 1.20 1200 mAh NCB -SC $4.25 $40.00 high, medium or kw speed. To and reconfigured if C 1.20 1200 mAh NCB -C $4.25 $40.00 simplify hook-up we recommend desired. Terminated C Heavy Duty 1.25 1800 mAh HDNCB-C $5.25 $42.50 using our membrane keypad, (CATS KPM-12 $1.25 each) which, with by 4 pin female connector D 1.20 1200 mAh NCB -D $4.50 $42.50 slight modification, works well with this device. Instructions included. (0.1' centers) on 4' leads. D Heavy Duty 1.25 4000 mAh HDNCB-D $7.00 $65.00 CATS ILSG4 $3.00 each CATS NCB 13U $3.(X) per Peck ORDER' TOL Li- FÑEE .1 J800-826-5432 -4 Call Or Write FAX (818) 781-2653 INFORMATION (818) 904-0524 DISCOVER For A Free 64 Page Minimum Order $10.00 All Orders Can Be Charged To Visa, Mastercard Or Discover Card Checks and Money Orders Accepted By Mail California, Add Sales Tax No C.O.D. 0 Catalog Shipping And Handling $3.50 mar the 48 Continental United States - All Others Including Alaska, Hawaii, Outside the U.S.A. P.R. 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Electronics® 1992 VOLUME 9 The Magazine for the Electronics Activist! © Gernsback Publications, Inc.

Abbreviations: (AR)Antkque Radio,-(C)Construction, (CB)Cornputer Bits, (CC)Circuit Circus, (D)Department, (DX)DX Listening, (ED)Ed- itorial (FS)Fun Software, (HOR)Hands-On Reports, (HR)Ham Radio, (G)Gizmo (LTR)Letters, (PTR)Product Test Report; (SS)Scanner

Scene, (TT)Think Tank .

TechnICs.RS-BX606 3 x 3 Visual Continuity Tester (Harrton)(C) Feb 53 Housekeep Before You Troubleshoot) Sep 66 Stereo Cassette Mall Cat Aug 68 Deck (Feldman)(PTR) Sep 27 i Feb 555-Based Alarm (Rakes)(CC) 65 Mail Ca'l Mar 68 Videonics Being Box Sound -Effects 558 Reassembling the Sky Buddy Dec 64 Mixer (O'Brian and Scaduto)(G) Mar 8 ; and Alarm Circuits, More (Yaconi,)(TT) Oct 72 Sky Buddy Saga, The May 66 Zenith -Bose Color TV Finale (Yacono)((TT''i'')) = -_ Nov 75 Therem n Plays Again, The Jan 76 Model ZB2794BG (O'Brian and Scaduto)(G) May 10 r 73 Timer, The (yecono)(TT) Sep Tips and Tidbits Nov 65 AudioSource SS Three/Il Pro -Logic-Surround -Sound 900-MHz Digital Cordless Telephone With The Collectors Contest Results Feb 63 Processo (O'Brian and Scaduto)(G) Oct 18 Tropez 900 DX (OBrian and Scaduto)(G) Jul 8 Archer Wireless AudioMdeo Distribution System= ' Audio-Techeicá SM-502 Audio - Radio Shack (O'Brian and Scaduto)(G) Jan 45 Mixer (Feidman)(PTR) - Dec 26 A Artisoft Lantastic Network Starter Kit Aug 12 AutoMap (C Brian and Scaduto)(G) Nov 5 AT&T Answering System Telephone - AUTOMOTIVE ABC Sports Goth Palm Springs Open 1532 (O'Brian and Scaduto)(G) Aug 13 Alpine 5951 Car CD Remote Changer Fathom Pictures (O'Brian and Scadu-to)(G) Feb 11 Audible Memo Alert (Rakes)(CC) Sep 70 System (O'Brian and Scaduto)(G) Jun12 Blaupunk Traveipilot Vehicle Navigation AC Une Monitor (Rakes)(CC) - Jul 70 AUDIO (SEE ALSO CD) - System (O'Brian and Scaduto)(G) Jun 7 JM/FM/Shortwave Stereo Cassette Receiver Ace Communicatom/ Trident: Build = CB/Scanner/Radar Detector (Saxon)(SS) Dec 80 A g. Philips' DC777 (O'Brian and Scaduto)(G) Jun 14 High -Energy Ignition System Alarm (Yacono)(TT) ; Feb 68 -ASAP Fax = - For stout Car (Ball)(C) _ Sep 31(LET)Dec 3 Amplifier (Rakes)(CC) r- =Jul 70 Command Communications Voltage Adapter For Your Car (Yacono)(C) Jun 47 AudioSource SS Three/II Pro -Logic Surround - - (O'Brian and Scaduto)(G) _ Aug 20 Circuits, More (Yacono)(TT)= 70 Sound Processor (O'Brian and Scaduto)(G) Oct 18 Apr Cobra Trapshooter Solar Stealth A/V - - _ - Audio-Technica SM-502 Audio Mixer Amplifier, Sansui AV-7000 (Feldrñan)(PTR)) May 27 (Feldman)(PTR) Dec 26 Radar Detector (O'Brian and Scaduto)(G) Jun 18 Electronic Tracking Foils Car Theives (Angus) Mar Receiver, Onkyo SV70 Pro (Feldman)(PTR) Jan 73 Bang & Olufsen Beosystem 2500 57 Installing and Troubleshooting Ace - Music System (Feldman)(PTR) Mar 23 Communications Car-AuiioSystems (Gipson) t Dec 35 AR -2800 Scanner (Saxon)(SS) Mar 82 Bass and Treble Booster Controls (Singmin)(C) Apr 34 Mazda RX-7 with Bose Audio - Trident - CB/Scanner/Radar Build System (O'Brian and Scaduto)(G) Sep 5 Detector (Saxon)(SS) Dec 80 A 49 -MHz FM Transmitter Becker)(C) Nov 39 Phtipa Dc777 AM/FM/Shortwave Stereo fiction -Packed Issue. An (Laron)(ED) Jan 2 A Speaker Protector (Flynn)(C) Mar 41 Casset-e Receiver (O'Brian and Scaduto)(G) Jun 14 An Eight-Channel Audio Switcher - Projects (Yacono)(Tr) Mar 73 Adjustable = - Dec 31 Voltage Monitor Sep 70 Race Remote Key Car -Control (Rakes)(CC) heGyeTinTuner" (Salas)(C) Jun 45 Voltage/Current Regulator (Rakes)(CC) Mar 70 System (O'Brian and Scaduto)(G) Jun 10 Carver OPL-33 Surround-Sotind Road to Tomorrow, Air on (Jehsen)(DX) - Feb 74 Traffic SW Processor/Amplifier (Feldman)(PTR) -Jul 27 The (O'Brian and Scaduto)(G) Jun 5 Alarm Choosing and Usingg Audio Axxess ffiuchScreen Personal Organizer (TT) 75 Circuit (Yacono Nov and Video Tape (S iwak) Nov 35 Oregon Scientific (O'Brian and Scaduto)(G) Sep 15 Circuits (Rakes)(CC) Jan 78 Citizen T530 Color LCD Pocket TV Clock/Chronometer Kit, TSM 6-Gigit (HOR) Jul26 with AM/FM Radio (O'Brian and Scaduto)(G) Jul 16 /Sounder Circuits (Rakes)(CC) Feb 65 Cobra Model 39 Pins S.O.S Portable B - Alexander Popov: Russia's,Radio Pioneer CB Radio (O'Brian and Scaduto)(G) Jan 47 (Rybak) - Aug 59 -Frequency Meter (Rakes)(CC) Apr 66 Baby Monitor, Build A (Caristi)(C) Oct 31 How to ABOUT - Back- America ALL Choose Audio Equipment (Spivak) Apr 35 UPS 250, Power Conversion (HOR) Sep 26 - Electncal Norse (Eggleston) - Jul 62 Electronically Tune Pianos and Other Bad Videotpes (Feldman) - Nov 31 Military Elecgronks (Hansen Aug 47 Instruments (Brown)(C) Feb 29 - Optoisotators and Optocoupiers ;Cam) Oct 53 Balun Tüensforne, Whale A (Carr)(HR) Feb 76 Indicatcrs and Acoustics (Martin) May 56 - Parallel -Port Signals (Yacono) Jan 38 Bandnass F)Iter (Rakes)(CC) - Installing and Troubleshooting 7 Jun 67 Proper Input Termination (Hansen) - Feb 58 Car-Audio Systems (Gipson) Dec 35 . Bang & Oiiisen Beosystem 2500 All -Purpose Insulation (Yacono)(TT) Jun 70 Macgnawx CD-ROM Drive/CD Player - Music System (Feldman)(PTR) Mar 23 3Alp)ne 5951 Car CD Remote Changer Model CDD461RS (O'Brian and Scaduto)(G)Feb 18 Bass:and Treble Booster Controls (Singmin)(C) Apr 34 Mazda RX-7 with Bose Audio System (O'Brian and Scaduto)(G) Jun 12 BATTERY System (O'Brian and Scaduto)(G) Sop 5 -Altemate Sensor (Rakes)(CC) Feb 65 Charger (Yecono)(TT) Apr 70 Memorex - - -Char Probe (YVacono)(T T) Mar 73 America Poweí Corn mrsionBack-(PS 250 (HOR) Sep 26 CDX-605 Extended -Play Personal - Clips coro)(NTi) Jun 70 Ameritron = Stereo (O'Brian and Scaduto)(G) May 18 Supper-Simple red-Battery: ICP-120 79 Triumph TS-5 Three -Piece Speaker - In-Rush Curren( Potecbr (Carr)(HR) Aug Rejuvenabr (Blechman)(C) Sep 63 ICP-240 ln-Rusn Current Protecor (HCarr)(HR) Aug 79 System (O'Brian and Scaduto)(G) Mar 5 4 QSK-5 External QSK Switch (Carr)( R) Aug 79 Onkyo SV70 Pro Audio/Video Beckman DM10XL Multimeter (HOR) Oct 22 Receiver Feldman)(PTR 73 Jan Big League - Answering System Telephone - Baseball Encyclopedia PA -System Primer, A (Allen) Feb 55 AT&T 1532 (O'Brian and Scaduto)(G) Aug 13 Franklin Electronics (O'Brian and Scaduto)(G) Nov 16 Philips DC777 AM'FMiShortwave Stereo - Bit of Mediterranean DX, A (Jenserii)(DX) 74 ANTENNA Cassette Receiver (O'Brian and Scaduto)(G) Jun 14 Apr Build A Precision .Antenna-Rotot Control Power Amplifier Rakes)(CC) Apr 66 Blaupunkt Travelpilot Vehicle Navigation System (Hocking)(C) _ = Jun 34 Radio Shack Archer Wireless AN Distribution - System (O'Brian and Scaduto)(G) Jun 7 Design and Build Loaded Dipolas (Carr)(HR) Mar 80 System (O'Brian and Scaduto)(G) Jan 45 Block -Heater Minder (Yacono)(rT) Mar 73 Dipoles Loaded Design and Bfiild (Carr)(HR) Mar 80 Ramsey FX-146 Two -Meter EM Transceiver = Boina Box Sound Effects Mixér For DX'ing the Low Bands, An (Carr)(HR) Nov 78 Kit (Kanter) - Dec 39 Quick & Dirty Quad, A (Deu (O Sep 48 Sansui Videonics (O'Brian and Scaduto)(G) Mar 8 Radio Shack Amplified VH /F/UHE/FM Audio Note A-4 Notebook Booster Controls, Bass and Treble (Singmin)(C) Apr 34 (Saxon)(SS) = Jun 76 Stereo (O'Brian and Scaduto)(G) Jul 10 Bose-Maida RX-7 Audio Receiving- Loop Jun 74 (Carr)(HR) Model AV-7000 AN Amplifier System (O'Brian and Scadulo)(G) Sep 5 -Rotor Control System, Build A (Feldman)(PTR) May 27 Brazi ian DZ. an a Rollercoaster Ride Precision-(Hocking)(C) Jun 34 Sanyo MCD-22885 Portable Audio (Jensen)rIX) _ = 72 Why Not Try A Folded Dipole? (Carr)(HR) Jan 87 System (O'Brian and Scaduto)(G) Dec 12 Jun Wire Beams: Gain On The Cheap (Carr) May 45 Sharp Bookshelf Stereo System/CD Changer Breakout Box, Build A (Yacono)(C) May 61 -ANTIQUE RADIO (Ellis)(D) Jan 76,Feb 63,Mar 68 Model CD -C900 (O'Brian and Scaduto)(G) Apr 16 Bridging Touo)i-Plate Sensor (Rakes)(CC) Aug 72 Sherwood SS -1500 Comppact(Stereo Apr 65,May 66,Jun 63 Britannica Sofreeres Compton's Concise _ Jul. 66 System (O'Brian and Scaduto)(G) - Mar 6 66,Aug 68,Sep Encyclopedia (O'Brian and Scaduto)(G) Feb 13 Oct 65,Nov 65,Dec 64 Sony MOP -605 CD/CDV/LP Player CleaningUp the -Sky 65 (Feldman)(PTR)- Oct 27 British Bost)ne Interpreter II BuddyOct Five Collectrs Contest Encore - Jul 66 Sound Master II PC Sound Board -Language Talking Transferor Coming: A New Restoration React Apr 65 Covox (O'Brian and Scaduto)(G) Jan 49 (O'Brian and Scaduto)(G) Sep 13 Getting Started on the Sky Buddy Jun 63 Subwoofe, Build A(Whitehead)(C) Jan 31 BUILD ABINITHE (SEE CONSTRUCTION) 53

AmericanRadioHistory.Com All About Parallel -Port Signals (Yacono) Jan 38 Holograms (lovine)(C) Aug 31,Sep 43 Amenca Power Conversion Negative Ion Generator (lovine)(C) Jan 29 Back -UPS 250 (HOR) Sep 26 PC -Based Stepper -Motor Controller Artisoft Lantastic Network (Antonuk)(C) Jun 41 CB Radio Starter Kit (O'Brian and Scaduto)(G) Aug 12 Protect Your Equipment With The Cobra Model 39 Plus S.O.S. Build - Power Block (Yacono)(C) Feb 37 (O'Brian and Scaduto)(G) Jan 47 a Quickie Breakout Box (Yacono)(C) May 61' Quick & Dirty Quad, A (Deupree)(C) Sep 48 CD the Printer Sentry (Yacono)(C) Mar 59 Simple Remote -Control Analyzer, Alpine 5951 Remote Changer the Universal RS -232 Connector A (Yacono and Spiwak)(C) Jun 38 System (O Brian and Scaduto)(G) Jun 12 (Tarchinski (C) Oct 82 Super-Simple Ned-Batts EuroSon America NSM C03101 10O -Disc Covox Sound Master II Rejuvenator (Blechman)) (Cl Sep 63 49 CD Changer (O'Brian and Scaduto)(G) Dec 5 - PC Sound Board (O'Brian and Scaduto)(G) Jan Telephone Ring Converter, The (Poeth)(C) Apr 38 DynaPulse 200M Blood-Pressure/Púlse Geten Systems CD Sound Consumer Alert (Laron)(ED) Nov 2 Musk Manager Software Monitor, Pulse Metric (O'Brian and Scaduto)(G) Dec 5 (O'Brian and Scaduto)(G) Sep 20 Lo ilech Fotoman Digital CONSUMER ELECTRONICS (SEE ALSO GIZMO, Sharp Model CD-C900iCCD Changer PRODUCT TEST REPORTS) /Bookshelf Stereo (O'Brian and Scaduto)(G) Apr 16 Camera (O'Brian and Scaduto)(G) Jul 18 NEC Ultralite III Notebook Computer Bad Videotapes (Feldman) Nov 31 CD -I Player Model CD1910 (O'Brian and Scaduto)(G) Apr12 Choosing And Using Audio Philips (O'Brian and Scaduto)(G) Feb 11 PC-Intedink File and Printer Sharing and Video Tape (Spiwak) Nov 35 CD-ROM System, Softworx (O Brian and Scaduto)(G) Aug 21 CONSUMER ELECTRONICS SHOW ' DeLorome Mapping's Street Atlas Plug'n Power Computer Interface Summer (O'Brian and Scaduto)(G) Oct 5 USA (O'Brian and Scaduto)(G) Nov 5 Radio Shack (O'Brian and Scaduto)(G) May 16 Winter (O'Brian and Scaduto)(G) -May 5 Grolier Electronic Encyclopedia Printer Spooling -Hardware Convenience Light for Remote Controls Feb 18 The New (O'Brian and Scaduto)(G) and Software (Blechman) Aug 40 (Spiwak)(C) Aug 37 Magnavox CD-ROM Drive/CD Player Model Troubleshooting Parallel Connections (Yacono) Feb 41 Cool Oldies Jukebox, PIMA CDD461RS (O'Brian and Scaduto)(G) Feb 18 COMPUTER BITS (HoltzmanXO)Jan 81,Feb 72,Mar 76 Feb 18 (O'Brian and Scaduto)(G) Feb 11 Microsoft Bookshelf (O'Brian and Scaduto)(G) 72,May 68,Jun 65 PC Globe Electronic Atlas Jul 68,Aug 71,Sep 68 Cop Talk: Understanding Police Feb 18 (O'Brian and Scaduto)(G) Oct 67,Nov 68,Dec 66 Communications (Quaranfieilo) Jan 61 PC Feb 18 -SIG Library (O'Brian and Scaduto)(G) .. Buying Your First (or Next) PC Aug 71 Cordless -Telephone Lock, CDTV Interactive Multimedia Player Computer Evolution Sep 68 Build A (Sokolowski)(C) Jul 44,(LET) Oct 3 Commodore (O'Bnan and Scaduto)(G) Feb 9 Integrated Software Tools Oct 67 Courier Procom UHF -FM Transceiver (Saxon)(SS) Sep 80 CABLE . Modem Mania Mar 76 Covox Sound Master II PC Sound Rack (Yacono)(TT) Jun 70 Norton for Feb 72 Board (O'Brian and Scaduto)(G) Jan 49 Tester, Build A (Recklies)(C) - Apr 53 Desktop Windows Utilities Version 6.0 Jan 81 Create a High -Voltage Miniature CAMCORDER Secret Life of a ComputerProducts Tornado.(Ford)(C) May 55 Canon Reviewer, The Jun 65 Feb Cross -Reference Software, Philips ECG (HOR) Dec 62 E40 8mm (Feldman)(PTR) 22 Siiing Up Your PC Needs Jul 68 Canovision 8 UCSI High -Band 8mm Tuning Up May 68 Current Injector, One Amp (Johnson)(C) Nov 46 Apr 6 Word JVC(OGR-AX5OUdComdpact)VHS BASIC Nov 68 (O'Brian and Scaduto)(G) Sep 6 D. BASIC II Dec 66 Sony Wizardry Apr 72 CCD-F501 (O'Brian and Scaduto)(G) Jan 50 dB or Not dB (Honeycutt) Aug 65 .CCD-FX510 8mm (O'Brian and Scaduto)(G) Oct 17 Concise Columbia Encyclopedia EC -7000 Franklin Electronics (O'Brian and Scaduto)(G) Mar 12 DC Motor Controller (Rakes)(CC) Mar 70 Canaries, The Incredible Hot (Clarke)(C) Jan 42 CONSTRUCTION D1T Telephone Security Device, Canon 3 x 3 Visual Continuity Tester (Hamppton)(C) Feb 53 Phone Guard (O'Brian and Scaduto)(G) Jul 8 8mm Camcorder, Canovision 8 UCS1 Bass and Treble Booster Controls (Singmin)(C) Apr 34 DX LISTENING (Jensen)(D) Jan 85,Feb 74,Mar 78 Apr High -Band (O'Brian and Scaduto)(G) 6 Build A Apr 74,May 78,Jun 72 E40 8mm Video Camcorder (Feldman)(PTR) Feb 22 49 -MHz FM Transmitter (Becker)(C) Nov 39 Jul 75,Aug 77,Sep 76 1 Capacitor -Discharge Driver (Rakes)(CC) Nov 72 Baby Monitor ('Carisbi)(C)) Oct 31 Oct 75,Nov 80.Dec 76 Car Alarm (Yacono)(TT) Oct 72 Breakout Box Yacono)(C) May 61 Air Traffic on SW Feb 74 Cable Tester ( cklies)(C) Apr 53 Bit of Mediterranean DX, A Apr 74 -Audio Car Systems, Installing and Compass, Talking (Mitschke)(C) Dec 42 Brazilian DX on a Rollercoaster Ride Jun 72 (Gipson) Dec 35 Troubleshooting Cordless -Telephone Lock (Sokolowski)(C) Jul 44 Changing Face of Russian DX. The Mar 78 Carver DPL-33 Surround -Sound Geiger Counter (lovine)(C) Jul 41 Exploring the Lower Shortwave Bands Oct 75

Processor/Amplifier (Feldman)(PTR) Jul 27 High -Energy Ignition System Into The Mailbag - Sep 76 Changing Face of Russian DX. The (Jensen)(0X) Mar 78 For Your Car (Ball)(C) Sep 31,(LET)Dec 3 Just -Chill" Out Jul 75 Holiday-Light Tester (Yacono and Spiwak)(C) Dec 59 Programming For SWLs Jan 85 Choosing and Using Audio and Video Tape Low -Cost Morse -Code Transmitter (Liste)(C) Aug 45 Radio Polonia is Gone; Polish Radio is Back Aug 77 (Spiwak) Nov 35 Miniature Tracking hansmitter (Vollono)(C) Jun 29 Shortwave Revival, The Nov 80 Circuit Grab Bag (Rakes)(CC) Jul 70 One -Amp Current Injector (Johnson)(C) Nov 46 United Nations Radio Dec 76 CIRCUIT CIRCUS (RakesXD) Jan 78,Feb 65,Mar 70 Personal Message Rerder (Williams)(C) Oct 39 WWV and WWVH Offer More Than You Think! May 78 Apr 66,May 73,Jun 67 Pop -Up Outdoor Lighting Data Discman Model 001 -EX. Sony Jul 70,Aug 72,Sep 70 System (Schmiedeberg)(C) May 38 (O'Brien and Scaduto)(G) Feb 13 Oct 69,Nov 72,Dec 68 Portable 2-MHz Frequency Counter (Cansti)(C) Jul 53 Daewoo DVP-1060N Video Cassette Player Alarm (Feldman)(PTR) Jun 26 Circuits Jan 78 Precision Antenna -Rotor Control ,Sounder Circuits Feb 65 System (Hocking)(C) Jun 34 Darkroom Timer Precision Darkroom Timer Build A Precision (Graf and Sheets)(C) Aug 53 Circuit Grab Bag . 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Dec 68 Subwoofer (Whitehead)(C) Jan 31 Design and Build Loaded Dipoles (Carr)(HR) Mar 80 More Voice Disguiser (Vollono)((C)] Dec 53 High -Voltage Circuits Nov 72 Voice -Mail Alert (O' Kelley )(C) Nov 53 Deskmate Automatic House Software Intruder -Detector Circuits - Aug 72 Voltage Adapter For Your Car (Yacono)(C) Jun 47 Radio Shack (O'Bnan and Scaduto)(G) May 18 Op -Amp Based Circuits Apr 66 Buifd,An Di Ital Regulator Applications Mar 70 Automatic Porch -Light Control (Ponting)(C) Mar 46 Frequency Counter, Heathkit IM -2410 (NOR) May 22 Citizen 1530 Color LCD Pocket TV Automatic Power Switch Multimeters, Fluke Series 10 (HOR) Apr 28 with AM'FM Radio (O'Brian and Scaduto)(G) Jul 16 For Your TV (Vaughn)(C) Nov 43 Sawtooth Generator, The (Carr)(HR) May 78 Classic Induction Coil, The (Czarnik)(C) Mar 35 Eight -Channel Audio Switcher, (Goebel)(C) Dec 31 Dipoles, Loaded, Design and Build (Carr)(HR) Mar 80 Emergency Telephone Dialer (Caristl)(C) Sep 39 Cleaning Up the Sky Buddy (Ellis)(AR) Oct 65 Do You Compute? (Yacono)(TT) Dec 72 Build The - Drive -Through Sermons (Saxon)(SS) Nov 82 Closed -Loop Alarm (Rakes)(CC) Jan 78 "Tiny Tuner" (Salas)(C) Jun 45 Cobra Idiot Box (Head)(C) Sep 53 Driver Circuit (Rakes)(CC) Nov 72 Model 39 Plus S.O.S Portable Printer Sentry (Yacono)(C) Mar 59 Dual -Tone Sounder (Rakes)(CC) Feb 65 CB Radio (O'Brian and Scaduto)(G) Jan 47 Universal RS -232 Connector (Tarchinski (C) Oct 62 Duofone Outgoing Call Restnctor Trapshooter Solar Stealth Classic Induction Coil, The (Czamik)(C) Mar 35 Radio Shack (O'Brian and Scaduto)(G) Mar 13 Radar Detector (O'Brian and Scaduto)(G) Jun 18 Convenience Light for Remote DynaPulse 200M ComputerizedBlood-PressutaPulse - Collectors Contest Encore (Ellis)(AR) Jul 66 Controls (Spiwak)(C) Aug 37 Monitor, Pulse Metric (O'Brian and Scaduto)(G) Sep 20 Colorburst SV1000 Video Digitizer (HOR) Jun 22 Create a High -Voltage Miniature Tomado (Ford)(C) May 55 Corning: A New Restoration Project (Ellis)(AR) Apr 65 Electric Waves and the Hertz E Command Communications ASAP Fax Oscillator (Czarnik)(C) Oct 45 (O'Brian and Scaduto)(G) Aug 20 Electromagnetic Ring Launcher (Vollono)(C) . Oct 42 EDITORIAL (Laron) Jan 2,Feb 2,Mar 2 Commodore CDTV Interactive Enlarging Light Meter for Photographic Apr 2,May 2,Jun 2 Multimedia Player (O'Bnan and Scaduto)(G) Feb 9 Printing, An (Graf and Sheets)(C) Apr 31 Jul 2,Aug 2,Sep 2 Experiment With Plasma Acoustics (lovine)(C) Oct 37 Compass, Talking (Mitschke)(C) Dec 42 Oct 2,Nov 2, Dec 2 Good Vibrations Printed -Circuit Board Action -Packed Issue, An Jan 2 Compton's Concise Encyclopedia Workstation (Yacono)(C) Apr 62 Consumer Alert Nov 2 Britannica Software (O'Brian and Scaduto)(G) Feb 13 How To Electronically Tune Pianos Electronics and the Automobile Jun 2 COMPUTER (SEE ALSO CD-ROM, COMPUTER BITS, and Other Instruments (Brown)(C) Feb 29 End of a Legend, The Aug 2 Incredible Hot Canaries, The (Clarke)(C) Jan 42 HARDWARE, SOFTWARE) - Get Up, Get Active! Apr 2 ASAP Fax, Command Make Your Own HDTV Update Mar 2 54 Communications (O'Brian and Scaduto)(G) Aug 20 High -Voltage Capacitors (Charlton)(C) ' , May 31 Importance of Perspective, The Sep 2

AmericanRadioHistory.Com Made In Japan May 2 AudioSource SS Three/II Pro -Logic Whistler Interstate Tripmate Multimedia Madness Feb 2 Surround -Sound Processor Oct 18 Highway Travel Planner Apr 10 Old Gear, New Lives Oct 2 Blaupunkt Travelpilot Vehicle Navigation Zenith -Bose Color TV Model Z82794BG May 10 Positioning Ourselves Jul 2 System Jun 7 Global Positioning System Edmund Scientific Optivisor Bose Mazda RX-7 Audio System Sep 5 GPS Navigation System, The (Fenton) Jul 31 Magnifying Glass (Carr)(HR) Aug 79 Britannica Software§ Compton§ Concise GPS Receiver Encyclopedia Feb 13 Eight -Channel Audio Dec 31" Sony Pyxis (O'Brian and Scadulo)(G) Jul 5 Switcher'(Goebel)(C) British Boston§ Interpreter II Five -Language Electric Waves and the Hertz Talking Translator Sep 13 Good Vibrations Printed -Circuit Board 62 Oscillator (Czarnik)(C) Oct 45 Canon 8mm Camcorder, Canovision 8 Workstation (Yacono)(C) Apr Electrical Noise, All About (Eggleston) Jul 62 UCS1 High -Band Apr 6 Grand Plano Kit, The OM (HOR) Jan 72 Citizen T530 Color LCD Pocket TV Electricity and Medicine in the Grolier Electronic Encyclopedia, with AM/FM Radio . Jul 16 19th Century (Czarnik) Sep 58 The New (O'Brian and Scaduto)(G) Feb 9,Feb 18 Cobra Guglielmo Marconi (Rybak) Apr 43 Electromagnetics Model 39 Plus S.O.S Portable Electromagnetic Ring Launcher (Voltono)(C) Oct 42 CB Radio Jan 47 David Hughes: Electromagnetic Trapshooter Solar Stealth Pioneer H (Rybak) Nov 60 Radar Detector Jun 18 Electronic Tracking Foils Command Communications ASAP Fax Aug 20 HDTV (Laron)(ED) Car Theives (Angus) Mar 57,(LET) Jul 3 Update Mar 2 - Commodore COW Interactive Multimedia HAM RADIO (Carr»D) Jan Electronically Tune Pianos and Other Player Feb 9 87,Feb 76,Ma(80 Instruments, How To (Brown)(C) Feb 29 Apr 76,May 76,Jun 74 Consumer Electronics Show Jul 77,Aug 79,Sep 78 ELECTRONICS LIBRARY (0) Jan 6,Feb 80,Mar 84 Summer 1992 Oct 5 Oct 78,Nov 78,Dec ?? Apr 80,May 82,Jun 78 Winter 1992 May 5 Antenna For DX'Ing the Low Bands, An Nov 78 Jul 82,Aug 84,Sep 82 Covox Sound Master II PC Sound Board Jan 49 Design and Build Loaded Dipoles Mar 80 Oct 83,Nov 84,Dec 82 DeLorome Mapping's Street Atlas USA Nov 5 Digital Sawtooth Generator, The May 76 ELECTRONICS DIT Telephone Security Device, Phone Guard Jul 8 OI Sol -Friend or Foe Jul 77 aPodt theu (Laron)(ED) Jun 00 EuroSon America's NSM CD3101 100 -Disc Receiving Loop Antennas Jun 74 Potpourri(Rakes)(CC) CD Changer Dec 5 Some Technicians Day (Steckler) Apr 40 Fathom Pictured ABC Sports Golt: More Spectrum Analyzer Stuff Oct 78 Elenco Micro -Master MM -8000 Palm Springs Open ' Feb 11 New Products and Some Questions Basic Systems Course (NOR) Aug 26 Franklin Electronics Answered Aug 79 Thoughts on Propagation Emergency Telephone Dialer, Build An (Caristi)(C) Sep 39 Big League Baseball Encyclopedia Nov 16 Radio Apr 76 Concise Columbia Encyclopedia Mar 12 Tools for Elmers and 78 End of a Legend, The (Laron)(ED) Aug 2 Elmees Sep Funex's Motion -Converter Exercise -Gear What's A Balun Transformer? Feb 76 Enlarging Light Meter for Photographic Interface Jan 46 Why Not Try A Folded Dipole? Jan 87 Printing, An(Grat and Sheet)(C) Apr 31. Celen Systems' CD Sound Music Manager Handheld That Won't Break the Bank, Etch Your Own PC Boards (Young) Jan 68 Software Dec 5 A (Saxon)(SS) Aug 82 Grolier Electronic Encyclopedia, The New Feb 5,Feb 18 EuroSon Americas NSM C03101 100 -Disc HANDS-ON REPORT (0) Jan 72,Feb Home -Office Round -Up 61,Mat 65 CD Changer (O'Brian and Scaduto)(G) Dec 5 28,May 22,Jun 22 (O'Brian and Scaduto)(G) Aug 5 Apr Experiment With Plasma Acoustics (lovine)(C) Oct 37 Instant Replay's Image Translator Jul 26,Aug 26,Sep 26 Experimenter§ Test -Bench Helpers May 73 VCR Nov 12 Oct 22,Nov 22,Dec 62 (Rakes)(CC) Standards Converting America Power JVC GR-AX5OU Compact VHS Camcorder Sep 6 Conversion Back -UPS 250 Sep 26 Exit Delay (Rakes)(CC) Aug 72 Beckman DM1OXL Multimeter Logitech Fotoman Digital Camera Oct 22 Colorburst Video Exploring the Lower Shortwave for Computers Jul 18 SV1000 Digitizer Jun 22 Bands (Jensen)(DX) Oct 75 Magnavox§ CD-ROM Drive/CD Elenco Micro -Master MM -8000 Basic Systems Course Extended On -Time Timer (Rakes)(CC) Dec 68 Player Model CDD461 RS Feb 18 Aug 26 Fluke Series -10 Digital Multimeters Mazda RX-7 with Bose Audio System Sep 5 Apr 28 Heathkit IM -2410 Digital Frequency Counter May 22 F Memorex - Mental Automation SuperCAD Electronics CDX-605 Extended -Play Personal Stereo May 18 Design Software Mar 65 lliumph TS -5 Three -Piece Speaker System Mar 5 OW Grand Piano Kit, The FACTCARDS (D) Jan 51,Feb 49,Mar 53 Jan 72 Philips Apr 49,May 49,Jun 48 Microsoft ECG Cross -Reference Software Dec 62 Protel Schematic Jul 49,Aug 49,Sep 49 Bookshelf Feb 18 Circuit -Design Software Feb 61 Oct 49,Nov 49,Dec 49 Multimedia Beethoven: The Ninth Symphony Feb 20 TSM Function -Generator Kit Fathom Pictures' ABC Sports Golf: Multi -Link§ SR2 Selective Ring Processor Aug 15 Nov 22 Multimedia Madness! (O'Brian and Feb 5 6 -Digit Alarm Clock/Chronometer Kit Jul 26 Palm Springs Open (O'Brian and Scaduto)(G) Feb 11 Scaduto)(G) NEC Ultralee III Notebook Computer Apr 12 HARDWARE Filter Circuits (Rakes)(CC) Jun 67 Oregon Scientific Axxess Touch -Screen Buying Your First (or Next) PC (Hoitzman)(CB) Aug 71 Fluke Series -10 Digital Multimeters (NOR) Apr 28 Personal Organizer Sep 15 Elenco Micro -Master MM -8000 Basic FM Transmitter, Build a 49 -MHz (Becker)(C) Nov 39 Panasonic PT-10L Compact Video Projector Apr 5 Systems Course (HOR) Aug 26 PC Globe Electronic Atlas Feb 18 Folded Dipole, Why Not Try A? (Carr)(HR) Jan 87 America Power Conversion PC Nov 5 Back-UPS 250 (HOR) Sep 26 Fotoman Digital Camera for Computers PC-SIGMapsLibrary Feb 18 Hayes Microcomputer Products, Logitech (O'Brian and Scaduto)(G) Jul 18 Philips Optima 96 (Holtzman)(CB) Mar 76 CD-I Player, Model CD1910 Feb 11 Franklin Electronics Headlights Reminder (Yacono)(TT) Mar 73 Big League Baseball DC777 AM/FM/Shortwave Stereo Heathkit IM -2410 Digital Encyclopedia (O'Brian and Scaduto)(G) Nov 16 Cassette Receiver Jun 14 Frequency Counter (HOR) May 22 Concise Columbia PIMA Cool Oldies Jukebox Feb 11 Encyclopedia (O'Brian and Scaduto)(G) Mar 12 Psygnosld Lemmings Feb 9 Hertz Oscillator, The, and Electric Waves (Czsmik)(C) Oct Frequency Counter, Portable 2 -MHz (Caristi)(C) Jul 53 Pulse Metric's DynaPulse 200M 45 Blood-Pressure/Pulse Monitor Sep 20 High -Energy Ignition Fridge Alarm (Yacono)(TT) Nov 75 System For Race's Remote Key Car-Control System Jun 10 Your Car (Ball)(C) Sep 31,(LET)Dec 3 Fun Software (Blechman)(D) Jan 83 Radio Shack High -Power Alarm Driver (Rakes)(CC) Jan 78 Real REC, A Jan 83 Archer Wireless Jan 45 AN Distribution System High -Voltage Fun With Deskmate Automatic Software May 16 House Capacitors, Analog Tachometer Circuits (Carr) Jul 59 Duofone Outgoing Call, Restrictor Mar 13 Make Your Own (Charlton)(C) May Op -Amps (Yacono)(TT) Jan 22 Plug'n'Power Computer Interface May 16 31, (LET) Aug 3 Circuits, More (Rakes)(CC) ,Nov 72 Testa Coils (Rakes)(CC) Oct 69 Poc etvision-26 LCD Color TV Apr 8 Miniature Tomado, Build A(Ford)(C) May 55 Funai TVCP 9T 9 -Inch TV/ Road to Tomorrow, The Jun 3 HISTORY Video Cassette Player (Feldman)(PTR) Nov 27 Rolodex Personal Planner Model EO-100 Oct 20 Alexander Popov; Sansul Audio Note A-4 Notebook Stereo Jul 10 Function -Generator Kit, TSM (HOR) Nov 22 Russia§ Radio Pioneer (Rybak) Aug 59 Funex§ Motion -Converter Exercise-Gear Sanyo David Hughes: Interface (O'Brien and Scaduto)(G) Jan 46 MCD-Z85 Portable Audio System Dec 12 Electromagnetic Pioneer (Rybak) Nov 60 Pulse Meter HRM-5520 Heart-Rate Monitor Jan 48 Electric Waves and the Sharp Bookshelf. 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(Laron)(ED) Apr 2 Data Diacman Model 001 -EX Feb 13 House Software and 16 Getting EV-S3000 HI8 VCR Dec 7 (O'Brian Scaduto)(G) May Plug'n'Power Computer Started on the Sky Buddy 63 Pyxis GPS Receiver Jul 5 (Ellis)(AR) Jun intedace(O'Brian to the Bottom of the Mailbag (Saxon)(SS) May 80 and Scaduto)(G) May 16 Tandy 2500SX/20Multimedia PC Feb 20 One For All 4 Universal Remote Give Your Handheld A Boost! 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Multimedia Beethoven Instant Replay (O'Brian and Scaduto)(G) Nov 12 (Holtzman)(CB) Aug 71 Outdoor Lighting System, Build A (O'Bdán and Scaduto)(G) Feb 20 Pop -Up (Schmledeberg)(C) May 38,(LET) Aug 2 Importance of Perspective, The (Laron)(ED) Sep 2 Word for Windows 2.0 OWI Grand Piano Kit, The (HOR) Jan 72 , Incredible Hot Canaries, The (Clarke)(C) Jan 42,(LET) Oct 67,Nov 68,Dec Apr 3 Wordofor Windows (Holtzman)(CB) 72 Induction Coil, The Classic (Czarnik)(C) Mar 35 Military Electronics, All About (Hansen) Aug 47 P Input Termination, All About Proper (Hansen) Feb 58 Miniature Tracking Transmitter, -Rush (Rakes)(CC) Mar 70 Build A (Vollono)(C) Jun 29 In Current Limiter PA -System Primer, A (Allen) Feb 55 Modem Maida (Holtzman)(CB) Mar 76 Installing and PC - Maintaining Telephone Systems (Young) Nov 55 Modified Squerewave Oscillator (Rakes)(CC) Jul 70 Based Stepper-Motor Troubleshooting Car-Audio Systems (G psonp Dec 35 Monitoring Controller (Antonuk)(C) Jun 41,(LET)Sep 3 Instant Replay's Image Translator Motion -Picture Sets (Saxon)(SS) Mar 82 Board Workstation, Standards Converting VCR Remote News Crews (Saxon)(SS) Dec 80 The "Good Vibrations (Yacono)(C) Apr 62 (O'Brian and Nov 12 Boards, Your Scaduto)(G) More Etch Own (Young) Jan 68 Globe Electronic Atlas Integrated Software Tools (Hollzman)(CB) Oct 67 558 and Alarm Circuits (Yacono (TT) Oct 72 (O'Brian and Scaduto)(G) Feb 18 Automotive Circuits Apr 70 Interpreter II Five-Language Talking Translator (Yacono)( lnterlink File and Printer Sharing System Fun With Op -Amps (Yacon:» Feb 68 British Boston (O'Bnan and Scaduto)(G) Sep 13 Sottworx (O'Brian and Scaduto)(G) Aug21 High -Voltage Circuits (Rakes)(CC) Nov 72 Interstate Tripmate Highway Travel Planner Maps (O'Brian Nov 5 -Intruder-Detector Circuits (Rakes)(CC) Aug 72 and Scaduto)(G) Whistler (O'Brian and Scaduto)(G) Apr 10 -SIGLibrary (O'Brian and Scaduto)(G) -Feb 18 Tips (Yacono)(TT) Jun 70 Into The Mailbag (Jensen)(DX) Sep 76 Panasonic PT -10L Compact Morse -Code Transmitter, Video Projector (O'Brian and Scaduto)(G) Apr 5 Intruder-Detector Circuits, Mom (Rakes)(CC) Aug 72 Build A Low -Cost (Lisle)(C) Aug 45 Parallel Intrusion -Indicator Circuit (Yacono)(TT) Oct 72 Motion -Converter Exercise -Gear Interface Connections, Troubleshooting (Yacono) Feb 41 Funex (O'Brian and Scaduto)(G) Jan 46 -Loop Alarm (Rakes)(CC) Jan 78 J Multi -Port Signals, All About (Yacono) Jan 38 -Loop Parallel Alarm (Rakes)(CC)Jan 78 Personal -Point Intrusion Detector (Yacono(TT) Oct 72 JVC GR-AX5OU Compact VHS Message Recorder, Build A (Wiltiams)(C) Oct 39 Camcorder (O'Brian and Scaduto)(G) Sep 6 Multi -Links SR2 Selective Ring Planner Model EO-100, Processor Aug 15 Just "Chill" Out (Jensen)(DX) Jul 75 (O'Brian and Scaduto)(G) Rolodex (O'Brian and Scaduto)(G) Oct 20 MULTIMEDIA Stereo. Memorex Extended BritannIca Software Compton Concise Play (O'Brian and Scaduto)(G) May 18

K Encyclopedia (O'Brian and Scaduto)(G) , Feb 13 Philips Commodore COW Interactive CD -I Player, Kaleidoscope, Sonic (Ray)(C) Oct 58 Multimedia Player (O'Brian and Scaduto)(G) Feb 9 Model CD1910 (O'Brian and Scaduto)(G) Feb 11 Fathom Pictures ABC Sports Golf: Kit Building Lives (Laron)(ED) Dec 2 DC777 AM/FM/Shortwave Stereo Cassette Palm Springs Open (O'Brian and Scaduto)(G) Feb 11 Receiver (O'Brian and Scaduto)(G) Jun 14 Madness (Laron)(ED) Feb 2 ECG Cross -Reference Software (HOR) Dec 62 Madnessf and Scaduto)(G) Feb 5 L (O'Brian PHONE (SEE ALSO TELEPHONE) Magnavox CD-ROM Drive/CD Player Guard Telephone Security Device, Model CDD461RS (O'Brian and Scaduto)(G) Feb 18 LCD Technology (Katznelson) Jun 61 Microsoft: DTI (O'Brian and Scaduto)(G) Jul 8 Une "Tester- (Yacono)(TT) Aug 75 Lamp-Switching Circuit (Rakes)(CC) Dec 68 Beethoven (Holtzman)(CB) Aug 71 -Une Interface(Yacono)(TT) Sep 73 Beethoven: The Ninth Symphony Lantastic Network Starter Kit -Use Indicator(Yacono)(TT) Sep 73 Artisoft (O'Brian and Scaduto)(G) Aug 12 (O'Brian and Scaduto (G) Feb 20 Philips CD -I Player PHOTOGRAPHY Lemmings, Psygnosis Ltd. Model CD1910 (O'Brian and Scaduto)(G) Feb 11 Build A Precision Darkroom Timer (O'Brian and Scaduto)(G) Feb 9 Software Roundup (O'Brian and Scaduto)(G) Mar 14 (Graf and Sheets)(C) Aug 53 LETTERS (D) Jan 4,Feb 3,Mar 3 Tandy 2500 SX-20 PC Enlarging Light Meter for Photographic Printing, Apr 3,May 3,Jun 3 (O'Brian and Scaduto)(G) Feb 20 An (Graf and Sheets)(C) Apr 31 Jul 3,Aug 3,Sep 3 Logitech Fotoman Digital Camera Muitimeter, Beckman DM1OXL (HOR) Oct 22 Oct 3,Nov 3,Dec 3 for Computers (O'Brian and Scaduto)(G) Jul 18 Light Plasma Acoustics, Experiment With (lovine)(C) Oct 37 -Dependent Sensor (Rakes)(CC) Aug 72 Plug's Pourer Computer Interlace Sources For Projects and Instruments (Carr) Mar 49 " Radio Shack (O'Brian and Scaduto)(G) May 16 Sources, Solid -State (Carr) Jun 31 N Polarity Indicator (Yacono)(TT) Apr 70 Lights-On Reminder (Yacono)(TT) Apr 70 NE602 Circuits One -Chip Receiver (Carr) Jun 53 Poor Mans Spectrum Analyzer (Carr)(HR) Oct 78 Logical Turn Signal (Yacono)(TT) Mar 73 NEC Uhrallte III Notebook Popov, Alexander: Logitech Fotoman Digital Camera Computer(O'Brian and Scaduto)(G) Apr 12 Russia's Radio Pioneer (Rybak) Aug 59 for Computers (O'Brian and Scaduto)(G) Jul 18 enOs NSM CD3101 100 -Disc CD Changer Porch -tight Control, ers Long -Period Monostable (Yacono)(TT) Oct 72 EuroSon America (O'Brian and Scaduto)(G) Dec 5 Build An Automatic (Ponting)(C) Mar 46 Look at the Mailbag, A (Saxon)(SS) Feb 78 1, Navigation System, The GPS (Fenton) Jul 31 Positioning Ourselves (Laron)(ED) Jul 2,(LET) Sep 3 rp Low -Frequency Antenna (Carr)(HR) Nov 78 Negative Ion Generator (lovine)(C) Jan 29 Power i C Low -Level Sounder (Rakes)(CC) Feb 65 New Kid on the Block (Saxon)(SS) Jan 89 Block, Protect Your Equipment re With The (Yacono)(C) Feb 37,(LET)May 3 NEW PRODUCTS (D) - Jan 14,Feb 86,Mar 88 Supply (Rakes)(CC) May 73 Apr 83,May 85,Jun 81 ui M Switch For Your TV, Automatic (Vaughn)(C) Nov 43 v_ Jul 84,Aug 86,Sep 88 Oct 85,Nov 86,Dec 85 Printer MC14538 Monostable Applications (Rakes)(CC) Dec 68 Sentry, Build the (Yacono)(C) Mar 59 Ó NiCd-Battery Rejuvenator, Made In Japan (Laron)(ED) May 2 Spooling-Hardware and Software (Blechman) Aug 40 1-3 Super -Simple (Blechman)(C) Sep 63 is> Magnavox's CD-ROM Drive/CD Player PIMA Cool Oldies Jukebox No -Doze Alarm (Rakes)(CC) Dec 68 t1J Model CDD461RS (O'Brian and Scaduto)(G) Feb 18 (O'Brian and Scaduto)(G) Feb 11 Jan 22 Magnetic Light (Czamik) Apr 57 Non -Inverting Amplifier (Yacono)(TT) PRODUCT TEST REPORT'S (Feldman)(D) Jan 73, ro Mali Call (Ellis)(AR) Aug 68 Norton Feb 22,Mar 23 j Desktop for Windows (Holtzman)(CB) Feb 72 26,May 27,Jun 26 Apr Ó Mail Call( (Ellis)(AR) Mar 68 Utilities Version &0 (Holtzman)(CB) Jan 81 Jul 27,Aug 26,Sep 27 Make Your Own Not Another Op -Amp Article! (Dougherty) Dec 57 Oct 27,Nov 27,Dec 26 High -Voltage Audio-Technica Audio Mixer SM-502 Dec 26 67 Capacitors (Charlton)(C) May 31,(LET) Aug 3 Notch Filter (Rakes)(CC) Jun Bang & Olufsen Beosystem 2500 Music System Mar 23 56 Holograms (lovine)(C) Aug 31,Sep 43 Null -Modem Cable (Yacono)(TT) Dec 72 Canon E40 8mm Video Camcorder Feb 22

AmericanRadioHistory.Com Carver DPL-33 Surround -Sound Sole Control Universal Replacement Processor/Amplifier Jul 27 Remote Control (O'Brian and Scaduto)(G) May 12 Daewoo DVP-1060N Video Cassette Player Jun 26 S Solid -State Funai TVCP 9T 9 -Inch TV/Video Cassette Driver (Rakes)(CC) Nov 72 Player Nov 27 SR2 Selective Ring Processor Light Sources (Carr) Jun 31 Memorex Multi -Link (O'Brian and Scaduto)(G) Aug 15 Some Model 87 Video Cassette Recorder Apr 26 Sansul More Spectrum Analyzer Stuff (Carr)(HR) Oct 78 Model 153 8mm Camcorder Aug 26 Audio Note A-4 Notebook New Products and Some Questions Onkyo SV70 Pro Audio/Video Receiver Jan 73 Stereo (O'Brian and Scaduto)(G) Jul 10 Answered (Can)(HR) Aug 79 Sansui Model AV-7000 NV Model AV-7000 AN - Thoughts on Radio Propagation (Carr)(HR) Apr 76 Amplifier May 27,(LET)Oct 3 Amplifier (Feldman)(PTR) May 27,(LET) Oct 3 Sonic Kaleidoscope, Build A (Ray)(C) Oct 58 Sony MDP-605 CD/CDV/LP Player Oct 27 Sanyo Technics RS -8X606 Stereo Cassette Deck Sep 27 Sony MCD-Z85 Portable Audio CCD-F501 Video Programming For SWLS (Jensen)(DX) Jan 85 System (O'Brian and Scaduto)(G) Dec 12 Camcorder (O'Brian and Scaduto)(G) Jan 50 Protect Your Equipment With Pulse Meter HRM-5520 CCD-FX510 8mm Heart Monitor 48 The Power Block (Yacono)(C) Feb 37,(LET)May 3 -Rate (O'Brian and Scaduto)(G) Jan Camcorder (O'Brian and Scaduto)(G) Oct 17 78,Mar 82 Protel Schematic Circuit -Design Software (HOR) Feb 61 SCANNER SCENE (Saxon)(D) Jan 89,Feb Data Discman Model Apr 78,May 80,Jun 76 DDt-EX O'Brian and Scaduto)(G) Feb 13 Psygnosis Lemmings 9 (O'Brian and Scaduto)(G) Feb Jul 79,Aug 82,Sep 80 EV S3000 H18 VCR (O'Brian and Scaduto)(G)) Dec 7 Public -Address Systems Oct 80,Nov 82,Dec 80 Pyxis GPS Receiver (O'Brian and Scaduto)(G) Jul 5 PA -System Primer, A A at Mailbag Feb 78 (Men) Feb 55 Look the Sound Master II PC Sound Board Pulse Meter HRM-5520 Heart -Rate Monitor Drive -Through Sermons Nov 82 Cevox (O'Brian and Scaduto)(G) Jan 49 Sanyo (O'Brian and'Scaduto)(G) Jan 48 Getting to the Bottom of the Mailbag May 80 Give Your Handheld A Boost! Jun 76 Soviet Space Station, Scanning A (Saxon)(SS) Apr 78 Pulse Metric's DynePulse 200M Blood-Pressure/Pulse Handheld That Won't Break the Bank, A Aug 82 Speaker Protector, Build A (Flynn)(C) Mar 41 Monitor (O'Brian and Scaduto)(G) Sep 20 Monitoring Spectrum Analyzer Motion-Picture Sets Mar82 Digital Sawtooth Generator, The (Carr)(HR) May 76 Remote News Crews Dec 80 Poor Mans (Carr)(HR) Oct 78 New Kid on the Block Jan 89 Spectrum Analyzer Stuff, o Scanning Some More (Carr)(HR) Oct 78 A Soviet Space Station Apr 78 Squarewave Oscillator (Rakes)(CC) Jul 70 Quick & Dirty Quad, A (Deupree)(C) the Friendly Skies Oct 80 Sep 48 Stac Electronics' Stacker (Holtzman)(CB) Jun 65 lining In the GMRS Sep 80 Vacation Scanning Jul79 Stepper-Motor Controller, PC -Based (Antonuk)(C) Jun 41 Schematic Circuit -Design Software, Protel (HOR) Feb 61 Stereo Cassette Deck, Technics RS-BX606 (Feldman)(PTR) Sep 27 R Secret Life of a Computer Products Reviewer, The (Holtzman)(CB) Jun 65 Street Atlas USA DeLorome Mapping (O'Brian and Scaduto)(G) Nov 5 RS -232 Connector, Universal (Tarchinskl)(C) Oct 62 Self -Triggering Timed -On Generator (Rakes)(CC) Dec 68 Subwootec Build A (Whitehead)(C) Jan 31 Race Remote Key Car -Control Series/Parallel Loop Alarm (Rakes)(CC) Jan 78 System (O'Brian and Scaduto)(G) Jun 10 Sump Alarm (Yacono)(TT) Sep 73 Sharp Bookshelf Stereo System/CD Changer RADAR DETECTOR Model CD -C900 (O'Brian and Scaduto)(G) Apr 16 Super Bandpass Filter (Rakes)(CC) Jun 67 Ace Communications' Trident Sherwood SS -1500 Compact Stereo Super-Simple NiCd-Battery CB/Scanner/Radar Detector (Saxon)(SS) Dec 80 Rejuvenator (Blechman)(C) Sep 63 Cobra Trapshooter Solar System (O'Brian and Scaduto)(G) Mar 6 SuperCAD Electronics Design Software Mar 65 Stealth (O'Brian and Scaduto)(G) Jun 18 Shinwa Communications (HOR) -001 (Saxon)(SS) RADIO (SEE ALSO ANTIQUE RADIO, DX LISTENING SR Scanner Jan 89 Surge Suppressor HAM RADIO, SCANNER SCENE) Shocking Facts About Surge Suppressors, Protect Your Equipment With Ace Communicationd Trident The (Angus) Feb 35 The Power Block (Yacono)(C) Feb 37 The Shocking Facts About (Angus) Feb 35,(LET)Jul 3 CB/Scanner/Radar Detector (Saxon)(SS) Dec 80 Shortwave Revival, The (Jensen)(DX) Nov 80 Surround -Sound Processor Build A Shutdown Circuit (Rakes)(CC) May 73 Low -Cost Morse -Code Transmitter (Lisle)(C) Aug 45 /Amplifier, Carver DPL-33 (Feldman)(PTR) Jul 27 Detectors May 70 49 -MHz FM Transmitter (Becker)(C) Nov 39 Signal (Yacono)(TT) Audio Source SS Signetics NE602 One (Carr) Jun 53 Three/II (O'Brian and Scaduto)(G) Oct 18 Cobra Model 39 Plus S.O.S Portable -Chip Receiver CB Radio (O'Brian and Scaduto)(G) Jan 47 Silent Alarm (Rakes)(CC) Jan 78 Guglielmo Marconi (Rybak) Apr 43 Simple Remote -Control Analyzer, Making the Connection (Carr) Dec 45 A (Yacono and Spiwak)(C) Jun 38 T Philips DL/1/ AM/FM/Shortwave Stereo Simulator Jan 83 Cassette Receiver (O'Brian and ScadutoXG) Jun 14 Software (Btechman)(FS) (Rakes)(CC) 70 Tachometer Circuits, Fun With Analog (Carr) Jul 59 Radio Polonia is Gone; Sinewave-to-Squarewave Converter Jul Polish Radio is Back (Jensen)(DX) Aug 77 Single -Plate Touch Sensor (Rakes)(CC) Aug 72 Talking Compass (Mitschke)(C) Dec 42 Radio Propagation, Sizing Up Your PC Needs (Holtzman)(CB) Jul 68 Tandy 2500SX/20 Multimedia PC (O'Brian and Scaduto)(G) Feb 20 Some Thoughts on (Carr)(HR) Apr 76 Sky Buddy Saga, The (Ellis)(AR) May 66 Technics RS-BX606 Cassette Radio Shack SOFTWARE Stereo Deck (Feldman)(PTR) Sep 27 Amplified VHF/UHF/FM Portable AutoMap (O'Brian and Scaduto)(G) Nov 5 Antenna (Saxon)(SS) Jun 76 Britannica Software Compton's Concise TELEPHONE (SEE ALSO PHONE) Archer Wireless NV Distribution Encyclopedia (O'Brian and Scaduto)(G) Feb 13 AT&T Answering System System (O'Brian and Scaduto)(G) Jan 45 Buying Your First (or Next) PC (Holtzman)(CB) Aug 71 Telephone 1532 (O'Brian and Scaduto)(G) Aug 13 Deskmate Automatic House DeLorome Mapping Amplifier (Yacono)(TT) Feb 68 Software (O'Brian and Scaduto)(G) May 16 Street Atlas USA (O'Brian and Scaduto)(G) Nov 5 Build Duolone Outgoing Call Fathom Pictures ABC Sports Golf: A Cordless -Telephone Lock (Sokolowski)(C) Jul 44 Restrictor (O'Brian and Scaduto)(G) Mar 13 Palm Springs Open (O'Brian and Scaduto)(G) Feb 11 A Voice -Mall Alert (O'Kelley)(C) Nov 53 Plug'n'Power Computer Gefen Systems CD Sound Music Manager An Emergency Telephone Dialer (Caristi)(C) Sep 39 Interface (O'Brian and Scaduto)(G) May 16 Software (O'Brian and Scaduto)(G) Dec 5 Circuit Parade (Yacono)(TT) Aug 75 Pocketvision26 Grolier Electronic Encyclopedia, Duofone Outgoing Call Restrictor LCD Color TV (O'Brian and Scaduto)(G) Apr 8 The New (O'Brian and Scaduto)(G) Feb 9,Feb 18 Radio Shack (O'Brian and Scaduto)(G) Mar 13 Realistic Integrated Software Tools (Holtzman)(CB) Oct 67 Intercom (Yacono)(TT) Aug 75 PRO -41 Scanner (Saxon)(SS) Feb 78,Aug 82 Mental Automation SuperCAD Phone Guard Telephone Security Device PRO -58 Scanner (Saxon)(SS) Jul 79 Electronics Design Software (HOR) Mar 65 DTI (O'Brian and Scaduto)(¡G) Jul 8 PRO -59 Scanner Saxon SS May 80 Microsoft Recording Control (Yacono)(TT) Aug 75 Ramsey FX-146 Two-Meter'FM Transceiver Bookshelf (O'Brian and Scaduto)(G) Feb 18 Ring Converter, The (Poeth)(C) Apr 38 Kit (Kanter) Dec 39 CD-ROM Multimedia Beethoven: The Ninth SR2 Selective Ring Processor (O'Brien Multi -Link (O'Brian and Scaduto)(G) Aug 15 Readers Requests (Yacono)(TT) Jul 73 Symphony and Scaduto)(G)Feb 20 Word for Windows 2.0 (Holtzman)(CB Feb 66 Systems, Installing and Maintaining (Young) Nov 55 Real REC, A (Blechman)(FS) Jan 83 Tele -Timer (Rakes)(CC) May 73 Word Wizardry (Holtzman)(CB) Apr 72 Tropez 900 DX Digital 900 -MHz Cordless Reassembling the Sky Buddy (Ellis)(AR) Dec 64 WordBASIC II (Holtzman)(CB) Dec 66 Telephone (O'Bnan and Scaduto)(G) Jul 8 Receiver Front -End, A One -Chip (Carr) Jun 53 Norton TELEVISION (SEE ALSO VIDEO) Receiving Loop Antennas (Carr)(HR) Jun 74 Desktop for Windows (Holtzman)(CB) Feb 72 Citizen T530 Color LCD Pocket TV Regenerative Capacitor -Discharge Utilities 6.0 (Holtzman)(CB) Jan 81 with AM/FM Radio (O'Brian and Scaduto)(G) Jul 16 Driver (Rakes)(CC) Nov 72 PC Globe Electronic Atlas Funai 9 -Inch TVNideo Regulator Applications (Rakes)(CC) Mar 70 (O'Brian and Scaduto)(G) Feb 18 Cassette Plar (Feldman)(PTR) Nov 27 Nov 5 Instant Replay Image Translator Standards Converting Remote PC Maps (O'Brian and Scaduto)(G) and Feb 18 VCR (O Brian and Scaduto)(G) Nov 12 -Control Analyzer, PC -SIG Library (O'Brian Scaduto)(G) Philips ECG Cross -Reference Software (HOR) Dec 62 Radio Shack Pocketvision-26 A Simple (Yacono and Spiwak)(C) 38 Jun PIMA Cool Oldies Jukebox LCD Color TV (O'Brian and Scaduto)(G) Apr 8 Control, Sole Control (O'Brian and Scaduto)(G) Feb 11 Sony EV-S3000 HI8 VCR Universal (O'Brian and Scaduto)(G) May 12 Protel Schematic Circuit -Design Software (HOR) Feb 61 (O'Brian and Scaduto)(G) Dec 7 Controls, Convenience Light for (Spiwak)(C) Aug 37 Psygnosis Lemmings (O'Brian and Scaduto)(G) Feb 9 TV Answer: What's theQuestion? (Angus) Sep 64 Key -Control Car System Radio Shack Deskmate Automatic Zenith -Bose Color TV Race (O'Brian and Jun 10 Scaduto)(G) House Software (O'Brian and Scaduto)(G) May 16 Model ZB279413G (O'Brian and Scaduto)(G) May 10 Resettable Shutdown Circuit (Rakes)(CC) May 73 Secret Life of a Computer Products Reviewer, TESLA COILS Resistor Calculations Made Easier (Axetson) Jun 58 The (Holtzman)(CB) Jun 65 Fun With (Rakes)(CC) Oct 69 Tuning May 68 Ring Up (Holtzman)(CB) Make Your Own High -Voltage Indicator (Yacono)(TT) Aug 75 Softwoni PC Intedink File and Printer Sharing Capacitors (Chartton)(C) May 31 Launcher, Electromagnetic (Votlono)(C) Oct 42 System (O'Brian and Scaduto)(G) Aug 21 Test-Bench Helpers, Experimenters (Rakes)(CC) May 73 (Yacono)(TT) May 70 Rolodex Personal Planner Solder Spool TEST EQUIPMENT - Model EO-100 (O'Brian and Scaduto)(G) Oct 20 Soldering -Iron Controller (Yacono and Spiwak)(C) May 53 3 K3 Visual Continuity Tester (Hampton)(C) Feb 53 57

AmericanRadioHistory.Com Beckman DM10XL Muttimeter (HOR) Oct 22 Function -Generator Kit (NOR) Nd-v 22 Sony MDP-605 CDtCOWLP Player (Feldman)(PTR) Oct 27 Build A Tuning TV Answer: What's the Question? (Angus) Sep 64 Cable Tester (Recklies)(C) Apr 53 in the GMRS (Saxon)(SS) Sao 80 VidtPax International Video Conversion One -Amp Current Injector (Johnson)(C) Nov 46 Up (Holtzman)(CB) May 68 Service (O'Brian and Scaduto)(G) Nov 13 Portable 2 -MHz Pianos and Other Instruments Frequency Counter (Caristi)(C) Jul 53 Electronically (Brown)(C) Feb 29 Videonics Boing Box Sound -Effects Buyerb Guide to Low-Cost Two - Mixer (O'Brian and Scaduto)(G) Mar 8 Oscilloscopes (Spiwak) Jul 35 -Meter FM Transceiver Kit, Video Titlemaker (O'Brian and Digital Sawtooth Generator, The (Can)(HR) May 76 Ramsey FX-146 (Kanter) Dec 39 Scaduto)(G) Sep 12 Fluke Series -10 Digital Multkneters (HOR) Apr 28 -Way AC Switch (Rakes)(CC) Sep 70 Videotapes, Bad (Feldman) Nov 31 Heathkit IM -2410 Digital Frequency TV Answer: What's the Question? (Angus) Sep 64 Counter (HOR) May 22 VldiPax International Video Conversion TV/Video Cassette Player, Simple Remote -Control Analyzer, Service (O'Brian and Scaduto)(G) Nov 13 Jun 38 Funai 9 -Inch (Feldman)(PTR) Nev 27 A (Yacono and Spiwak)(C) VlsIble-Light TSM Function -Generator Kit (HOR) Nov 22 Receiver (Rakes)(CC) Mar 70 Some More Spectrum Analyzer Stuff (Carr)(HR) Oct 78 U Transmitter (Rakes)(CC) Mar 70 Tester, 3x 3 Visual Continuity (Hampton)(C) Feb 53 Visual Continuity Tester, 31(3 (Hampton)(C) Feb 53 Theremin Police Understanding Communications: Voice Coming: A New Restoration Project (Ellis)(AR) Apr'65 Cop Talk (Quarantiello) 61 Jin (Vollono)(C) Dec Theremin Plays Again, The (Ellis)(AR) Jan 76 Disguiser 53 United Nations Radio (Jensen)(DX) Dec 76 -Mall Alert, Build A (O'Keiley)(C) Nov 53 THINK TANK (Yacono)(D) Jan 22,Feb 68,Mar 73 Universal Electronics One For All 4 Home Control - Voltage Apr 70,Mey 70,Jun 70 Remote Control (O'Brian and Scaduto)(G) Nc-v 20 Adaptor For Your A 47 Jul 73,Aug 75,Sep 73 Car, Build (Yacono)(C) Jun 70 Oct 72,Nov 75,Dec 72 Universal RS -232 Connector, Build The -Level Indicator (Rakes)(CC) Sep Probe (Rakes)(CC) Sep 558 Finale Nov 75 (Tarchinskt)(C) Dot 62 70 558 Timer, The Sep 73 Automotive Projects Mar 73 V W Do You Compute? Dec 72 Fun With Op -Amps Jan 22 What's A Balun Transformer? (Carr)(HR) Feb 76 Microclips and More May 70 VCR Funai TVCP 9T 9 -Inch TVNideo Whistler Interstate Tdpmate Travel More Highway Cassette Player (Feldman)(PTR) Ngv 27 Planner (O'Brian and Scaduto)(G) Apr 10 558 and Alarm Circuits Oct 72 Instant Replay's Image Translator Standards Why Not Try A Folded Dipole? (Carr)(HR) Jan 87 Automotive Circuits Apr 70 Converting VCR Núv 12 Feb 68 Fun With Op -Amps Memorex Model 87 (Feldman)(PTR) &To Winter Consumer Electronics Show, Tips Jun 70 Sony 2EV-S3000 HI8 VCR Dec 7 The (O'Brian and Scaduto)(G) May 5 Reader's Requests Jul 73 Vacation Scanning (Saxon)(SS) Jul 79 Wire Beams: Gain On Telephone Circuit Parade Aug 75 Variable The Cheap (Carr) May 45,(LET) Oct 3 Tiny Tuner, Build The (Salas)(C) Jun 45 -Frequency Oscillator (Rakes)(CC) Ott 69 With The Collectors Contest Results (Ellis)(AR) Feb 63 Tips and Tidbits (Ellis)(AR) Nov 65 Trip -Point Shutdown Circuit (Rakes)(CC) May 73 Word Tools for Elmers and Elmees (Carr)(HR) Sep 78 Voltage Divider (Rakes)(CC) Sap 70 BASIC (Noltzman)(CB) Nov 68 for Windows, Microsoft (Holtzman)(CB) Apr 72 Touch Switch Circuit (Rakes)(CC) Jul70 VIDEO (SEE ALSO CAMCORDER, TELEVISION, /CR) Build an Automatic Power Switch for Windows 2.0, Microsoft Transistor Checker (Rakes)(CC) May 73 For Your TV (Vaughn)(C) Nov 43 (Holtzman)(CB) Oct 87,Nov 68,Dec 66 Transmitter, FM (Becker)(C) Nov 39 Colorburst SV1000 Video Digitizer (HOR) J to 22 Word Wizardry (Holtzman)(CB) Apr 72 Travelpilot Vehicle Navigation System Daewoo DVP-1060N Video WWV and WWVH Otter Mom (Feldman)(PTR) Jen 28 Blaupunkt (O'Brian and Scaduto)(G) Jun 7 Cassette Player Than You Think! (Jensen)(DX) May 78 HDTV Update (Laron)(ED) Mar 2 hi -Color Indicator (Yacono)(TT) Apr 70 Onkyo SV70 Pro Audio/Video Trimmer Tool (Yacono)(TT) Jun 70 Receiver (Feldman)(PTR) Jan 73 Z Tropez 900 DX Digital 900 -MHz Panasonic PT-10L Compact - Cordless Telephone (O'Brian and Scaduto)(G) Jul 8 Video Projector (O'Brian and Scaduto)(G) Apr 5 Zenith -Bose Color TV Radio Shack Archer Wireless AN Model ZB27948G (O'Brian and Scaduto)(G) May 10 Troubleshooting Parallel Connections (Yacono) Feb 41 Distribution System (O'Brian and Scaduto)(G) Jan 45 TSM Sansui Model AV-7000 NV 6 -Digit Alarm ClocluChronometer Kit (NOR) Jul 26 Amplifier (Feldman)(PTR) May 27

"I have a logic probe-I'm looking for an 'illogic probe' for "To be honest, it started out to be a pocket calculator-but it sort 58 things that don't make sense" of got out of hand"

AmericanRadioHistory.Com ALL ABOUT MICRO PROCESSORS

The most common complaint I We explore what makes these hear from'old-world hams and technicians about micro- powerful chips tick in processors is that there is no conve- an informative nient way to visualize how.they work. They make that assumption because but intuitive most books treat microprocessors as black boxes. They ask the user to style. memorize what a given microprocessor does rather than try to explain how the microprocessor works. BY TIMOTHY D. GREEN Few introductory books, if any, give the user away to visualize and understand how a microprocessor works. The lack of information is due in part to the fact that microprocessors are internally complex devices that re- dress containing the number to be quire the user to juggle many facts added. The microprocessor will ex- about their hardware and software. ecute the addition just after that aAd However, although they are "messy" place the result into memory. to use in practice, they are built out of At this point, you might be wonder- simple logic devices and can be easi- ing: How does all of this occur? What ly explained in a block -diagram fash- drives the microprocessor to do those ion. things? How are the address and con- In this article, we will break -down trol lines activated? How are these the microprocessor into simple logic things done in sequence? What building blocks such as counters, causes the microprocessor to get its latches, and read -only -memories. from the microprocessor. Each of own instructions from the ROM? How That will make it easier to show you these devices are given unique ad- are these instructions interpreted and how and why a microprocessor works. dress codes. As far as the micro- translated into action? However, for the sake of brevity it will processor is concerned, the sole To help explain, look at the internal - be assumed that you more or less function of each device is to send view of a typical microprocessor know what those building blocks do. data to or accept data from the mi- shown in Fig. 2. It shows several regis- croprocessor on the data -bus lines ters, which the microprocessor uses to A Microprocessor System. Figure when it is selected by the micro- keep track of data and address infor- 1 shows a small microprocessor sys- processor. mation, the arithmetic -logic -unit (or tem. The microprocessor can get its For example, assume that the mi- ALU), which performs math and logic program instructions from the Read - croprocessor is about to execute an operations, and the internal data bus, Only Memory (ROM). It can get data "add to memory" instruction. This in- which allows the transfer of informa- from or place data in the Random - struction consists of the "ADD" instruction within the microprocessor. It also Access Memory (RAM), and it might tion code and two halves of a 16 -bit shows an instruction register tied to a get or send data through the ports. address in RAM. The microprocessor "control -unit," which is the source of The control -lines, "read," 'Write," "in- will get the instruction code by setting several control -lines. Although the put/output". and "memory" go to the the address lines to the.address of the control -lines shown only point in the ROM, RAM, and input/output ports as "ADD" instruction in ROM and activat- direction of the external devices they shown. ing the "read" and "memory" control - control, every part of the micropro- The microprocessor directs the lines. This will select the ROM and al- cessor is connected to and manipu- ROM, RAM, and the ports with its con- low the instruction code to fill the data lated by the control -unit. trol and address lines according to bus so that the microprocessor can The control -unit runs the micro- the microprocessor's internal controls read the ADD instruction. Then the mi- processor, sequences and com- and according to the instructions it croprocessor will set-up and read mands its internal parts, and interprets receives. The. ROM, RAM, and ports from the next sequential address and and executes the instructions in full. are enslaved through the control - read the ROM two more times to get Completely understanding exactly and address -line signals that come the two halves of the 16 -bit RAM ad - how the control -unit works is the key to 59

AmericanRadioHistory.Com ADDRESS BUS output data. This sequence of instructions or steps would then be repeated over and over again as part of an instruction loop. That can be done for a schedule of 100 channels, 200 ROM DATA BUS channels, or any number of channels. Figure 5 shows another such simple controller running a beacon transmit- CHIP READ ter and Morse A fixed - SELECT sending code. length, repeating message in Morse CHIP SELECT ADDRESS code would be programmed into the DECODE READ LOGIC PROM with the sequence to turn on WRITE the transmitter and the keyer. ADDRESS Both of the circuits in Figs. 4 and 5 BUS (16 SELECT could have been controlled by the

. microprocessor system back in Fig. 1. READ COCK CLOCK The ROM in the microprocessor sys- OSC. WRITE tem would just have to contain a se- MEMORY quence of instructions to manipulate MICRO- INPUT/ the output -port lines, which would in PROCESSOR OUTPUT turn control the external devices. Both l\ the simple controller and the micro- DATA BUS (8) processor system solve similar control POWER RESET RESET problems and allow the user to program simple, arbitrary -length control SELECT sequences with great flexibility. How- SELECT OUTPUT INPUT ever, the microprocessor can do PORT PORT mathematical and logic operations on its data as well. The reason that a simple controller OUTPUTS INPUTS lacking an instruction latch cannot Fig. 1. In a microprocessor system, the microprocessor treats all the other system components as devices to give data to and receive data from. serve as the control -unit in a microprocessor is that it would only be ca- understanding how and why a micro- devices. For example, when used indi- pable of running one sequence of processor works. vidually, these lines can drive other instructions located in the PROM. A mi- gates, flip-flops, counters, latches, croprocessor's control -unit must be A Controller. The controller circuit PROM's, RAM's, and other devices. able to run many different control se- shown in Fig. 3 is not a true control unit, As the counter counts, it provides quences, therefore it must be able to but it has the feel of one and contains new addresses to the PROM, which accept input from the outside world most of the essentials of a control unit. sends out the pre-programmed data to select the desired control se- Ignoring the dashed portion of the from each requested address. One of quence from those in the PROM. That circuit and the instruction latch for these lines is fed back to the "clear" input is received by the control -unit's now, a binary counter counts clock input of the counter as shown in Fig. 3. instruction latch. pulses and sends its count to the ad- That allows a fixed -length process to dress lines of a programmable ROM run in a continuous loop provided the The Instruction Latch. To help point (PROM). The PROM looks at the ad- data and instructions needed for the out the importance of the instruction dress and sends the value of the data process are stored in the PROM. latch look back at Fig. 3. Note that the located in the address to the input of More PROM's can be added to pro- binary-counter outputs only set the the octal latch that's connected to the vide more control lines, as indicated lowest .six address lines of the PROM. rn control lines. That latch captures and by the parts with the dashed outlines. That allows the counter to count out holds this data at its outputs, thus ma- The outputs of the counter would feed up to 64 sequence steps at a time nipulating the control lines. the same corresponding address rather than stepping through the Notice that the binary counter lines of each new PROM. whole'PROM. clocks on the falling -edges of the The instruction latch supplies the clock, while the latch clocks on the Some Examples. Figure 4 shows a PROM with eight, additional, higher - ó rising-edges. That is done for making controller without an instruction latch address lines. The input latch and the á clean, stable transitions in the latch- running a data -acquisition system. counter, together, are used to index es output data and for synchronization. The user of this system would program 256 separate sequences of up to 64 /171 The latch -output lines can be used the PROM to select an analog chan- steps each. In a microprocessor, each á as a set to represent a number or val- nel to be sent through the analog of the 256 possible latch codes are ue. They can also be used individually multiplexer, start and read the ana- used as instruction or operation 60 as controlling signals to other logic log -to -digital -converter, and latch the codes. Each instruction code is a sin-

AmericanRadioHistory.Com ACCUMULATOR TEMPORARY PROGRAM PROGRAM J mCOUNTER (LOW) 1.COUNTER (HIGH),

ALU INPUT #1 INPUT #2'i FUNCTION- SELECT LINES ARITHMETIC/LOGIC UNIT (TO CONTROL - (ALU) ' DATA COUNTER DATA COUNTER UN IT) (LOW) (HIGH)

STATUS OUTPUT DATA OUTPUT

r. CONTROL -UNIT

EXTERNAL STATUS INTERNAL STATUS DATA OUTPUT PROM LATCH

INSTRUCTION INTERNAL DATA BUS (8) REGISTER

PROM LATCH

ADDRESS LATCH ADDRESS LATCH PROM LATCH DATA BUFFER (LOW) (HIGH) COUNTER

PRJM íseji

L J (SEE (8) (8)

t . EXTERNAL ADDRESS BUS ADDRESS BUS CLOCK RESET READ WRITE MEMORY INPUT DATA BUS HALF -HIGH HALF -LOW /OUTPUT

Fig. 2. The inside of a microprocessor is much like the system the microprocessor sits in; there's a data bus for communication between the components. gle code that indexes a whole se- programmed to activate those two lower speed than a simple controller. quence of sub -operations within the lines at the same time to get a new However, a microprocessor can per- microprocessor. A sub -operation may instruction at the end of a sequence, form many different operations as is, be used to manipulate the controls of which might be smaller'than 64 steps while a controler would require .a a latch, a counter, or the ALU. Each long. PROM for each sequence that it must sequence of sub -operations will per- The control -unit shown in Fig. 3 must perform. form one complete microprocessor be modified in two ways to enable it Back in Fig. 4 for example, we operation (such as ADD), to handle some special instructions showed how a simple controller As mentioned earlier, more PROM's and features. These will be discussed would operate a data -acquisition sys- may be added to the control -unit, so later, as they are needed. tem "directly" from a PROM. There is a that the new PROM's. share the same one-to-one correspondence be- address bus as the first PROM. It is not Microprocessors vs. Controlers. tween a PROM's latched data and the uncommon for a microprocessor's The operation of a microprocessor is operation it performs. However, if the control -unit to have more ,than 80 directly parallel to the operation of data -acquisition system were con- control lines (or, more than ten the simple controller. However, since trolled by the microprocessor system PROM's). the microprocessor itself contains a of Fig. 1, the microprocessor system Two of the control lines from the out- control unit, the microprocessor oper- would manipulate the output -port put latches of the PROM's go to the ates at a "higher level" than a control- lines to control the same devices "clear -counter" input of the counter ler. In this higher level, the micro- using a series of "indirect" instructions and to the "latch" control of the in- processor controls the external system from the ROM. There would be no struction latch. The PROM must be in "indirect" instruction steps, at a one-to-one correspondence be- 61

AmericanRadioHistory.Com ALWAYS ON A Simple Microprocessor. Looking back at Fig. 2 as a guide, let's discuss

I ADDITIONAL p- FROM LATCH - J`\ I ENABLE '- the intended functions of each of the PROM -- l (8) i.)I A DATA -11'N I microprocessor sub -components. -1,/ I 16K OCTAL CONTROL LINES L f I (27128) I' LINES LATCH TO DEVICES detailed explanation of these sub (8) FROM COUNTER r (8) rL' Í_ (74374) r-t components is essential for program- (6) i l CHIP 1------F ming the control -unit. i - READ II LATCH LSELECT -7-- The microprocessor's internal, óJ L eight -line data bus connects the out- ALWAYS ON puts of each register to its own input and to the inputs of the other registers ALWAYS OUTPUT to allow data to be transferred to and ON ENABLE ALU, TO 8 HIGHER from the registers, the the data OCTAL ADDRESS 8 BIT INSTRUCTION. buffer, and the address latches. Any LINES CODE LATCH DATA register, latch, or device that sends D7 I INSTRUC must -TION LATCH D6 data onto the internal data bus have three -state (low/high/high-im- D5 pedance) logic outputs so that it can D4 PROM "disconnect" itself from the bus when 16K D3 (27128) it is not needed, as only one device CLEAR D2 I may place data on the bus at any

D1 I one time. .BINARY TO 6 LOWER COUNTER ADDRESS DO Each register in Fig. 2, including LINES both the low and high halves of the CHIP READ CLOCK SELECT program -counter and the data - counter, is an octal latch. Each regis- b b`. ter, or latch, has two control lines to be ALWAYS connected to the control -unit's output latches: one to "latch" or capture the data at the inputs and the other to COUNT LATCH FROM f CLOCK/OSC. LATCH "three -state" its outputs. The "three - OCTAL TO CLEAR LATCH state". control is also called the "output TO LATCH OUTPUT (74374) enable." ENABLE The arithmetic/logic unit (ALU) performs such operations as addition, ALWAYS ON subtraction, incrementing, decre- CONTROL LINES TO DEVICES menting, and logical operations on Fig. 3. The control unit is the key to how a microprocessor processes data and the data present at its inputs. The se- performs operations. There are simple descrete controllers available that lack the lection of each operation and which instruction latch shown here. input or inputs to operate on is made by giving a binary code to the ALU's tween the instruction codes in the tions since the instructions are de- control lines. These control lines are, of

ROM of Fig. 1 and the controlling sig- coded by the microprocessor's con- course, connected to the control -unit. nals on the output -port lines. trol -unit. The ALU can accept data from the Furthermore, the simple controllers To summarize, although the micro- temporary register and any other reg- suitable for Figs. 4 and 5 will run their processor does its controlling "indi- ister except the instruction register. The control sequences exactly at the rectly" and more slowly than the temporary register is used as a tem- clock speed. The slowest device that simple controller, it uses a fixed set of porary holding place for ALU input these controllers control is the only instructions which are easily coded data. thing that limits their operating speed. into a single PROM. In general, a mi- The accumulator register is used 2? A microprocessor, on the other hand, croprocessor is a compromised con- only for the programmer's data. The m will run its control -instruction se - troller. Instead of building a separate control -unit must not disturb its con- quence at a lower speed than the and complete control -unit to perform tents unless an instruction tells it to do clock speed. That is because the mi- each complex task, a microprocessor so. croprocessor must run a few sub -op - is used to perform each task with a The.ALU has outputs for data results ó erations at the clock speed for each sequence of instructions selected and the "status" of the results. The _0 control operation it must perform. from a fixed set of instructions. The data -output register is a temporary w Another key difference is that if the complete freedom that comes with holding place for the results of the ásimple controller had a lot of devices using a control -unit is traded for the ALU's operations. The ALU's status infor- to control, it would need several restricted freedom of using a given mation indicates whether or not there PROM's. However, the microprocessor microprocessor's structure and in- was a bit carried during addition, 62 needs only one PROM for its instruc- struction set, (Continued on page 93)

AmericanRadioHistory.Com Nearly everyone knows that the ability to send messages from one place to another in the form of an electrical code has been around for about 150 years. But relatively few realize that the instruments, and even the code itself, have undergone many changes in that time. In this article I'd like to take a look at some of the devices that opened the age of electrical communication, and then trace the development of the Morse code and code -sending devices to the present time.

The First Telegraph. Samuel Morse didn't use either a key or a letter code for his first telegraph. Instead he used a "portrule," a number code and a "register." The portrule was a wooden stick with a groove designed to hold small lead blocks. (Similar devices were used in printing.) Each of the lead blocks had protrusions arranged to represent the numbers zero through nine. In use, the portrule was pulled past pan electrical contact and the protrusions closed the circuit in a sequence corresponding to the number. At the receiving end, a strip of paper was automatically inscribed by the register with marks corresponding to the protrusions and numbers. An operator would then look up the numbers in a códe book and write down the THE appropriate letter, word, or phrase. There are a few holdovers of that system still in use-the familiar "73" or "best regards" of ham oper- CODE MAKERS ators and the "30" used to. mark the end of newspaper and wire -service Trace the history of code and code -sending gear from its stories are two examples of that. The system worked-but slowly. Un- earliest days to today's computerized equipment. like others who were experimenting with electrical telegraphs at the time, BY LARRY LISLE, K9P2T Morse didn't stop inventing when he had a system that barely functioned. demonstration between Washington Code That is the version of the code With the help of his assistant and part- and Baltimore was more elaborate, that was adopted for used when wire- ner, Alfred Vail, Morse improved his with a pivoting wooden lever and less (radio) telegraphy was de- telegraph until it was simple, reliable, screw adjustments. Conventional or veloped. and convenient to use. The portrule "straight" keys have changed very lit- As operators became more experi- and number code were the first to go. tle since then. enced, it was found they could under- Morse and Vail also dropped the stand the sound of the register as Enter the Telegraph Key. The first number and códe-book idea. After easily as they could the marks on the telegraph key was a strip of brass fas- several false starts, they came up with moving strip of paper. That led to the tened to a block of wood and a wire the system of dots and dashes fcr let- invention of the "sounder" by Vail in at one end, and bei it upwards at an ters, numbers, and punctuation that the early 1850's. The sounder con- angle over a contact at the other. became known as the American sisted of an electromagnet and a Pushing down on a knob at the free Morse Code. In 1851 the code was lightweight, movable arm that clicked end of the strip closed the circuit. modified in Europe and called the wren the current flowed and the cir- The key used by Morse in his 1844 Continental or International Morse cuit was closed, and clicked again 63

AmericanRadioHistory.Com wired for electricity, code -practice machines were built to run with electric motors, and later ones had built-in code oscillators. Incidentally, should : you pick up one of these old devices from a flea market, etc., be very care- -. ful. Some were built to poor standards P of safety, and even in the better ones the insulation may have deteriorated. If the earphones, key, or cabinet is connected directly to the power line,

I you might receive a deadly shock.

12, Improved Sending Devices. ` Sending high-speed messages for A Signal Electric key and sounder in a hours at a time with a straight key homemade metal resonator. could be very tiring. Many operators had An Instructograph AC -powered code - their careers cut short by a con- practice machine. This model had a dition called a "glass arm." That was built-in oscillator. The knobs were used caused by the constant switching of to control volume and speed. opposing sets of muscles in the fore -

0n'

Here's an assortment of semi -automatic keys or "bugs:" From left to right they are an old and new Vibroplex, a McElroy, and a Johnson Speed -X. A spring -powered Morse -code sending machine. A perforated paper tape was pulled past the electrical contact and operated a sounder hooked to the binding posts. The speed control is located at the opposite corner. ol. when the current was turned off. A short interval between the clicks was a dot; a long interval was a dash. ,1 ó ._p. Trying to copy a sounder in a noisy office could be difficult, especially if there were several other sounders going at the same time. The usual prac- An assortment of electronic keyers: From left to right they are A Mon -Key (the first tice was to mount the sounder ina electronic keyer), the "TO" by Hallicrafters, and models made by Hammarlund and wooden or sheet -metal box, open on Heath. A "Vibro-keyer" bug sits on top of the Hammarlund unit. one side, which was called a resonator. That made the clicking seem per tape punched with holes to rep- arm from full on to full off and back louder and gave each sounder a dis- resent the dots and dashes of the again. tinctive tone. code. A spring -wound motor pulled The earliest remedy was the "dou- Learning the code in the wire -tele- the tape past a contact, which oper- ble -speed key" also known as the graph days usually meant hanging ated a sounder. When wireless came "double -action key" or more corn- around the telegraph office and in, a buzzer was substituted for the mbnly, the "sideswiper," The side- doing odd jobs. During the slack peri- sounder. These machines could be swiper key moves from side to side ods, the operator might then be per- adjusted for whatever speed you instead of up and down. There are suaded to teach the code on a wanted-something not always pos- cóntacts on either side and the oper- practice set, Another way, if you could sible when a live operator was doing ator holds the key against one of afford it. was to rent a code -sending the sending! them longer for dashes than for dots. 64 machine. These devices used a pa- As more and more homes were (Continued on page 89)

AmericanRadioHistory.Com ANTIQUE RADIO

By Marc Ellis ast month, we began the main tuning and band - Take the time to make reassembling our Sky spread control drives were good clear notes when dis-

Buddy model S -19R re- restrung with new cord. And connecting wiring. .

ceiver, which had been that cord had better last . The speaker in the S -19R partly dismantlec for clean- quite a long time! There's no has six leads: Iwo to the ing and dial -cord way to restring those con- field coil (which also serves The Sky restringing. In this column, trols without disconnecting as the power -supply filter we'll be completing the job the subchassis (an arduous choke), two to the primary Buddy: All and testing the set for oper- job indeed) and removing of the output transformer ation. For those who have it from the main chassis. (which is mounted on the Together just joined us, the Sky Buddy The removal (not to men= speaker frame), and Iwo was Hallicrafters' "low -end" tion the subsequent from the voice -coil circuit to Again! shortwave receiver during reinstallation) was almost as the closed-circuit head- the late 1930's. As such, it difficult as the disconnec- phone jack (which mutes was quite a popular starter tion. The subchassis is the speaker when phones set for shortwave listeners virtually locked in place by are plugged in). the radio's. front panel, In a hurry to get on with

which must have been in- the restoration work, I had stalled after the subchassis made only a few rough was. And the front panel is sketches to indicate where not now removable be- those leads were con- cause it was fastened to the nected. When reinstallation

main chassis by some type time rolled around, I found

of a spot-welding process. that I hadn't adequately Taking out the subchassis differentiated between a . with the front panel in pair of terminal lugs where place requires a bit of inge- a couple of the wires were nuity and a bit of forcing, as to be connected. (I'd care-

I described in last month's fully marked one 'top" and

column. And if anyone out one "bottom," but now I there in reader -land has wasn't sure whether "top" figured a method for re- referred to the terminal that The front view of the Sky Buddy-all together again and ready to stringing the Sky Buddy's dial would be uppermost with try out. cords without going the set in operating position through this exercise, I'd or to the terminal that was and newly-licensed hams. certainly like to hear about uppermost with the chassis This series of articles be- it! upside down for servicing.)

gan in the May, 1992 issue, I had also indicated the with a discussion of the Sky THE LOUDSPEAKER wrong tube socket as the Buddy's history. Restoration 'HASSLE connection point for a third work started the following With the tuning sub- lead. And just to add to the month, and has been con- assembly back in place, complication, the color tinuing at intervals ever the only major component coding on the grimy and since. still to be installed was the time -faded wires no longer loudspeaker. That took a seemed as clear to me as it

THE DIAL CORD little longer than necessary did when I removed them. HASSLE because of uncertainties "Big deal," you may think. Last month's column about the lead connec- "Ellis has a schematic of the

chronicled the disassembly, tions. And while I can set. What's so hard about cleaning, reassembly, and probably blame the Hal- finding the connection reinstallation of the sub - licrafters design engineers points for six speaker chassis containing the main for the previously described leads?" In actuality, how-

tuning/bandspread capaci- hassle, I can blame only ever, that was more of a

tor and associated drive myself for the difficulty I had problem than it seemed. pulleys. In the process, both with the speaker. The moral: Set designers of the era 65

AmericanRadioHistory.Com were not as concerned switch terminal that it didn't but perhaps someone will where I definitely was not about keeping intercón- look disconnected. now. If you have information receiving the full comple-

necting leads short as they I ran into a similar prob- about this issue, how about ment of local stations. The were about cabling them lem with an Echophone set contacting me? I'll be de- tuning in that band also

neatly together. So I found that I restored on these lighted to print your seemed a little broad, and myself attempting to trace pages a few years ago and recollections in this column. signals were weak. A bad IF

circuit pathways from one I know why, in all likelihood, stage maybe? Only further side of the chassis to the those wires were cut. During FINAL ASSEMBLY testing will tell! other via wires obscurely World War II, in a security - AND TEST bundled up in harnesses. related move to restrict After cleaning and re- READER COMMENTS

The confusion I created shortwave listening, our installing the knobs, tuning Now that the Sky Buddy

for myself extended what government apparently en- dial, and dial pointer, all I restoration has been run- should have been a 10 - couraged radio service had left to do before the ning for a while, some minute job into one that shops to disable certain S -19R could be tried out reader comments have

lasted for more than an shortwave bands on sets was to add a line cord. The started to come in, and I hour. So don't make the that were brought in for old one, dangerously have room for a couple of

I mistake I did! Take the time repair. cracked and deteriorated, the letters here. To start off, to sketch accurate di- I've heard of cases where had been removed early in was pleased to receive a agrams showing the the zealous service man the restoration project. note from Alan Douglas, au-

locations of all the connec- crushed the shortwave I wish I could tell you that thor of the very important tions that you remove. In coils, damaging them I'd been able to dig up a three -volume reference set, the long run, that will save beyond all hope of repair. perfect period replace- Radio Manufacturers of the you time and possibly even Luckily this radio (and the ment for the cord, but I'm 1920's (published by Vestal prevent you from damag- Echophone) were disabled not even sure what the Press, Vestal, NY and avail- ing irreplaceable parts by in far gentler fashion, so original looked like. The able from most major wiring them incorrectly. that all functions could easi- clumsy solder joints and sources of antique -radio lit- shreds of previous wiring at erature). the set's cord connections In his communication indicated that the deterio- (which was typed on a re- rated cord had itself been production of Atwater Kent

a replacement. So I satis- Manufacturing Works sta- fied myself by installing a tionary dating from the length of modern black zip - early 1900's!), Alan pointed

cord having an innocuous out that the yellow deposit I a molded plug. had reported cleaning

When I first turned the set from the S-19R's IF transfor- on, not a sound came forth. mers and other metal parts My heart sank because the (October, 1992 issue) could

set had played a bit when I very well have been a r tried it out prior to dis- compound of cadmium.

assembly. I figured that I Cadmium plating of steel must have messed up the parts, he went on to point The newly reassembled Sky Buddy as seen from the rear. The speaker wiring after all, per- out, began about 1930 and tuning control subchassis (behind the IF cans) was a bear to get haps burning out the 'unit in has been common ever back in! the process. Then I realized since. that the problem could just Cadmium plating nor- ECHOES OF WWII ly be restored after the war. as well be dirty contacts on mally has a bright metallic

I have to admit, though, But I doubt that either of the the phone jack's speaker - look, but after long-term ex- that being forced to rum- folks who cut those wires muting switch. posure to the atmosphere, mage around tracing wires would have imagined that That hunch was correct, cadmium oxide (brown)

did have its up -side! I acci- half a century would pass since shorting out the and/or cadmium sulfide dentally discovered that before the severed con- switch with a clip lead im- (yellow) deposits can form one of the wires from the nections were found and mediately brought the Sky on the surface. When

oscillator coil to the band - soldered back in place! Buddy back to life. I could cleaning off such deposits switch had been neatly In one of the Echophone hear activity on all bands during restoration projects,

severed, effectively disab- articles, I invited readers and, since I was hooked up extreme caution should be

ling band 2 (1.7-5.5 MHz). It who might know something to a good antenna, I even used because cadmium is would have otherwise about those wartime gov- pulled in several foreign a poisonous substance and taken me quite a bit of time ernment guidelines for shortwave stations. inhaling its dust can be to find that problem be- disabling shortwave sets to Performance was lack- quite dangerous. cause the wire was cut so write and enlighten us. No luster, however, particularly Many thanks to Alán.for cleanly and so close to the on the broadcast (Continued on page 91) 66 one responded back then, band-

AmericanRadioHistory.Com COMPUTERII BITS I

By Jeff Holtzman n past columns, I have And because said user has scribe these rich new forms recommended buying as undoubtedly paid signifi- of information. much computing muscle as cant dues in mastering a you can possibly afford. program or Iwo (DOS Word- A DIGITAL WORLD

However, in a letter that I Perfect or 1-2-3, for We're already living in a recently received, reader T. example), he or she resists digital world; it's only going G. chides me for being too change in direct proportion to become more so. Tech- The XT gung-ho with those recom- to the effort expended in nologies including High mendations. Perhaps he is paying those dues-notto Definition Television (HDTV) Syndrome right. It is possible to get by mention the status earned and ISDN are going to with less. But getting by is thereby. make a big difference dur-

not the issue. I don't recom- There's a significant prob- ing the next decade. You mend purchasing powerful lem with that world view. It may have hea7d of ISDN. computers for the sake of assumes that computers Officially, the acronym ownership. I'm not advccat- are here simply to improve stands for Integrated Ser- the efficiency of common vices Digital Network, but procedures-such as writ- due to interminable delays, ing letters to the editor. Of wags have for years sup- course they do that, but plied alternate expansions: they also openup a whole e.g., It Still Does Nothing. new world of experience However, that is chang- that has no analog in past ing. Some analysts think that experience. Think about ISDN will be available to video games. Think about more than 50% of tele- the kind of show that you phone subscribers by the get at a good planetarium. end of 1993-little more Think about the effects that than a year from now. We'll you see in movies like Roger have to buy new phones, Rabbit and Terminator 2. and they'll be expensive at Fig. 1. In just a few years, all -digital global communications Think about what compos- first. But we'll be able to networks and high-powered personal computers will totally dwarf ers like Todd Rundgren cnd throw away our modems, the already tremendous changes of the past 30 years in the fields Philip Glass are doing. Think install a cheap digital port of communications, consumer electronics, computers, and about fractal graphics. (somewhat like an RS -232 entertainment. Think about desktop pub- card), and get 27 times lishing (which didn't exist ten better performance than a ing some high-tech form of years ago). Think about 2400 bps modem. We'll conspicuous consumption. desktop -video production also get videophones, My reason is simple: It takes (coming in a big way in the cheap. Talk to Grandma a lot of power to deal with next few years). during the holidays, let her what I'll call "rich data." Those phenomena have see the kids. one thing in common: We're going to need RICH DATA They're all built around rich even greater bandwidth Computer users who data: gobs of formatted than ISDN can provide to have never used a Macin- text, high -resolution true - purchase and download tosh, an Amiga, a NeXT color graphics, animation, videos on demand. Pilot station, a workstation run- recorded and synthesized sites on both coasts already ning Motif or Open Look, or sound, and full -motion vid- provide that type of service. a plain old PC running Win- eo. Like it or not, rich data is In the business environment, dows may have trouble here to stay. The "MTV gen- presentations have evolved imagining computer eration" simply demands it. rapidly over the past few screens displaying anything Those demands are tear- years to include fancier but 80 x 25 screens of text. ing down the wall that's and fancier graphical ele- Consequently, that type of dividing education and en- ments. That trend is likely to user has trouble imagining tertainment. Some use the continue by adding sound, why anyone would want to. term "infotainment" to de- simple animations (e.g., 67

AmericanRadioHistory.Com projected sales growth), these tools, It's good train- and video clips. Clearly, ing, both professionally and GET le^ that environment demands personally. powerful computers to ac- That "middle-aged SMART ay% complish anything beyond school teacher" type of Quick & Cheap With Books! mindless data entry. complacency is on the way Factories need to collect out. Businesses like GM, IBM, data, predict and schedule Digital, and countless others TALK! maintenance activities, and are trimming the fat. Com- Now you can álert management to in- panies large and small are get a ham license ventory dnd manufacturing releasing those who never without a Morse showed enough initiative to code test! problems, Workers need All About Ham on -demand video training. learn new things, to rein- Radio by Harry A 30 -second video (avail- vent themselves, to improve Helms tells you how. It covers what able instantaneously across their worth to the company. hams do... how to select equip- the network) detailing a I only wonder how they'll ment and antennas... using packet jobs when their radio and ham satellites... operat- complex assembly pro- get new ing procedures... and contácting cedure is infinitely more skills are five, ten, and even hams in foreign countries! Also. effective than five pages of twenty years old. includes an introduction to radio dense prose and static di- Nonetheless, education and electronics. Start talking theory agrams. Imagine 'receiving will follow, and soon. If the to the world today! Only $19.95. a VHS tape or interactive public institutions don't get CD-ROM instead of printed with the program, expect LISTEN! assembly instructions when greater and greater num- .., Listen to history as buying your child's (or bers of private institutions to it happens via grandchild's) next bike. take over. Washington is al- shortwave radio! Schools have unique ready talking about Shortwave Listenhig needs that far exceed the education credits that can GuidebookGuidebookm by . gy capabilities of the Apple II's be applied to both public Harry Helms tells and 064's that once prom- and private schools. you all about the shortwave bands, when and where to listen, reception ised salvation. The U.S. has supported a patterns, and how to select the "secure," complacent way

shortwave radio that's right for you. TEACHER'S PEST . of life for the past 60 or so

It also profiles major world broad- Reader T. G. mentions years. However, that ostrich casters. Includes hundreds of "many middle-aged school attitude has come back to frequencies for stations worldwide teachers. , . who only want haunt us. The old ways were and times to hear them. Just $16.95. to write letters and perhaps good enough, so we didn't look at CompuServe," and modernize our steel plants, BUILD! then goes on to imply that our semiconductor fabrica- \,, The Forest Nlis they don't need big 486's tion, or our educational w \\. Engheees Notebook with lots of RAM and hard systems. Now we're paying - rby Forrest Mims disk space, That's probably the price. We didn't mod- (who else?) includes true. ernize, so the Pacific Rim -"?_ hundreds of It is also regrettable. It is countries surged ahead. applications circuits using today's most popular linear and digital ICs! regrettable both for the The solution is not to try to Forrest includes complete data for teachers themselves and regain dominance in par-

each IC, such as pin connections, for our society. I have sev- ticular industries. The world more! logic tables, waveforms, & eral school -age children, is much too complex for If you experiment with ICs, I that. But that's a topic for you gotta get this book! and frankly don't want A steal at $14.95. them to have those kinds of another time. For now, don't

teachers. I want my kids to let anyone fool you. The You can get HighText books at world is going digital. Every- your favorite technical bookstore, be taught by war -scarred electronics parts dealer, or radio veterans who've been tried thing will be available in equipment dealer. Or order direct by fire, who've lived to tell digital form. You need lots from HighText! Include $3 per about it, and who are ea- of computer power to re- book for shipping ($4 Canada, ger for more. I want my kids trieve, create, and $5 elsewhere). CA please add sales manipulate rich data. tax. U.S. funds only please. to experience, first-hand, the new possibilities that It's scary, and it's hard. But these technologies are even the smallest successes -IighTexns,tnc. opening up. I want my kids are satisfying. And a big 7128 Miramar Road, Suite 15L to experience the frustra- success will let you leave San Diego, CA 92121 tions and the Joys of using your mark on the world. 68

AmericanRadioHistory.Com t. 71.1»417`.,,G t . -,.. - , 1/1;1' ii. á4 ive a Friend a Year of `Electronics `Fun this C1ristm.as:

Does fighting the crowds at Christmas short- SAVE MONEY...A great gift to receive, Popular circuit your holiday fun? Don't blow a fuse this Electronics is also a great gift for you to give! ,.. year. ..for the friend who shares your love of The Special Holiday Rate saves you $23.05* off project -oriented electronics - or a youngster the newsstand price on each gift. You can save 'wp who may need only a spark to ignite a life-long another $23.05* when you start or extend your interest - give a gift subscription to Popular own subscription at the same time. It's ours Electronics. "thank -you" for sharing Popular Electronics with a friend this Christmas. Popular Electronics readers get the know how they need to build exciting, educational, and Send no money, unless you prefer. We'll be glad useful projects like these ...a touch light dim- to bill you in January, next year. Just take a mer...a traveler's theft alarm ...an economy brief moment to go over your gift list and make NiCd battery charger...a voice synthesizer... sure you haven't forgotten anyone who might a portable frequency counter. ..a shortwave appreciate the many benefits of Popular Elec- converter...a stereo graphic equalizer...even tronics. Then write the names on the attached a robot! Gift Certificate and mail it back in the postage -paid reply envelope. ..we'll take it from PLUS...Gizmo, our honest and straight-shoot- there! ing review of the latest consumer -electronics gear. ..Market Center, featuring mail-order Your friends will receive a handsome gift an- 4 merchants that are ready to help you in all your nouncement card signed with your name just ,Y; - hobby activities...articles and columns cover- before Christmas. And L11 through the new year' ng every aspect of the electronics hobby - they'll remember and appreciate your thought- including antique radio, shortwave listening, ful gift! So don't blow a fuse...take it easy and ham radio, computers, scanners, circuit de- enjoy the holidays. Give Christmas gifts of Pop- sign, and more! ular Electronics!

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AmericanRadioHistory.Com CIRCUIT CIRCUS

By Charles D. Rakes his visit, we are featuring Cl and potentiometer R4; MODIFIED RELAXATION several circuits built R4 ties the emitter to the OSCILLATOR around the unijunction tran- positive -supply rail. When Our second UJT circuit, sistor (or UJT as it is the emitter voltage is below shown in Fig. 2; is a slightly commonly called). The UJT the trigger level of the UJT, modified version of the is a two -layer, three -terminal the impedance between its basic relaxation circuit PN device that has two emitter and B1 is very high. shown in Fig. 1. A small 8- or bases (B1 and B2) and a But when the emitter volt- 16 -ohm speaker replaces single emitter (known as the age rises to the trigger B1's ground return resistor gate). If you're relatively level, the impedance be- (R3), while a three -position UJT Circuits new to electronics or just tween the emitter and B1 switch (S1) and three ca- haven't crossed paths with drops dramatically. pacitors (C1-C3) replace the UJT, then the following At the instant that power circuits just may spark an is applied to the circuit, the interest in using this device voltage across Cl is near +9-16V in some future circuit or ground. As time passes, the project. voltage across C1 rises. R1 When the charge on C1 R3 3.3K R2 RELAXATION reaches the UJT's trigger 25K 27051 OSCILLATOR level, Q1 turns on, discharg-

Figure 1 shows a UJT con- ing C1's stored energy into 01 figured as a relaxation BI's negative -return resistor, 2N2645 oscillator. In that circuit, the R3, producing a fast -rising C3 positive supply voltage is pulse at B1. At the same 10-20 connected to B2, while the instant, the resistance be- SPKR1 negative side of the supply tween B2 and ground is C 8 OR 1652 is B1. connected to The lowered, causing a similar S1 emitter terminal is con- but opposite (negative) nected to the junction pulse at B2. After C1 has Fig. 2. In the modified formed by timing capacitor discharged, the cycle starts relaxation oscillator, an 8- or over. 16 -ohm speaker replaces R3, The basic UJT circuit in while a three -position switch +9-16V Fig. 1 can supply output (SI) and three capacitors R4 signals for a number of ap- (CI-C3) replace CI. 100K R2 plications. It may be used 27052 R1 as a clock generator, a C1 in Fig. 1. The switch/ 6.8K timer circuit, a sawtooth capacitor combination is 01 generator, or a positive- or used to set the oscillator to 2N28481 negative -pulse generator. operate .in one of the three

Cl R3 .1 2252 PARTS LIST FOR THE RELAXATION OSCILLATOR

Fig. 1. In he relaxation RESISTORS oscillator, B2 is connected to (All fixed resistors are 1/4 -watt, 5% units.) the positive supply rail R1- 6800 -ohm through R2, while BI is R2 -270 -ohm connected to the negative R3 -22 -ohm side of the supply, and its R4-100,000 -ohm potentiometer emitter terminal (commonly known as the gate) is ADDITIONAL PARTS AND MATERIALS connected to the junction C1 -0.1-µF, ceramic -disc capacitor formed by timing capacitor Ql-2N2646 or similar unijunction transistor Cl and potentiometer R4 Perfboard materials, enclosure, 9 -16 -volt power source, wire, (which ties the emitter to the solder; hardware, etc. 70 positive -supply rail).

AmericanRadioHistory.Com +20-25V

PARTS LIST FOR THE R1 MODIFIED RELAXATION OSCILLATOR D1 3.3K 6V ZENER RESISTORS R6 R3 50K (All fixed resistors are %a -watt, 5% units.) 2700 R1 -3300 -ohm VW + 12V R2 -270 -ohm 02 R3 -25,000 -ohm potentiometer 2N3906 CAPACITORS C1-0.1-1LF, ceramic -disc 2N3904 Q1 C2 -1-µF, 25-WVDC, electrolytic R2 2N2848 C3 -10-20-11F, 25-WVDC, electrolytic 10K ADDITIONAL PARTS AND MATERIALS Ql-2N2646 or similar unijunction transistor R4 R5 10K S1-SP3T switch C1 470 .1- 100 :v. SPKR1-8- or 16-ohm speaker Perfboard materials, enclosure, 9 -16 -volt power source, wire, solder, hardware, etc. Fig. 4. In addition to the constant -current charging source used in the previous circuit, this one throws a buffer stage into the game, allowing the circuit to drive low -impedance loads. frequency ranges offered IMPROVED -LINEARITY by this circuit. That switch/ RELAXATION PARTS LIST FOR THE' capacitor combination OSCILLATOR CONSTANT-CURRENT RELAXATION OSCILLATOR serves as a coarse frequen- Our next UJT entry, see cy adjust, Fine -frequency Fig. 3, takes the basic Fig. 1 SEMICONDUCTORS ' adjustments for this circuit circuit a bit further-adding Q1 -2N2646 or similar unijunction transistor are made via R3, a 25k a separate charging Q2-2N3906 general-purpose PNP silicon transistor potentiometer. source to improve output Q3 -2N3904 general-purpose NPN silicon transistor When S1 is in either the A waveform linearity. In any Dl -6 -volt,. %z -watt Zenet diode or B position, the circuit RC charging circuit that's RESISTORS functions as a variable, au- not driven by a constant - (All fixed resistors are 1/4 -watt, 5%a units.) dio -frequency oscillator. current source, linearity is R1 -3300 -ohm When S1 is placed in the C always better at the begin- R2=10,000 -ohm , x position, the circuit oper- ning and deteriorates as R3 -270 -ohm = ates as a metronome. The charging progresses. R4 17 ohm R5 -10,000 -ohm circuit's frequency of opera- By using a higher source R6-50,000 -ohm potentiometer tion can be reduced by voltage, the timing capaci- increasing the values of ei- tor charges more rapidly, ADDITIONAL PARTS AND MATERIALS. ther C3 or R3. thereby improving the lin- C1 -0.01-100-11F, see text earity of the output Periboard materials, enclosure, '12- and 20 -25 -volt power wire, hardware, etc. sawtooth waveform. The sources, solder, higher voltage won't damage the UJT because ger voltage, which is always CONSTANT-CURRENT the voltage at the emitter less than the operating volt- RELAXATION never exceeds the UJT's trig - age applied to B2. OSCILLATOR The circuit in Fig. 4 adds a constant -current charging PARTS LIST FOR THE source and a buffer stage IMPROVED -LINEARITY RELAXATION OSCILLATOR to the basic UJT circuit in Fig. 1. In the Fig. 4 circuit, RESISTORS Q2, D1, R1, and R6 form a (All resistors are 1/4 -watt, 5% units.) fixed simple constant -current R1 -4700 -ohm Fig. 3. Linearity in this regulator. The level of regu- R2-270 -ohm ;~ version of the relaxation R3 -ohm lated current is set by the oscillator has been improved -47 R4 -100,000 -ohm potentiometer values of R1 and R6. Tran- by adding a separate sistor Q2's collector supplies charging source. By using a ADDITIONAL PARTS AND MATERIALS the constant charging cur- higher source voltage to Ql-2N2646 or similar unijunction transistor rent to C1, whose value is charge the timing capacitor, C1 -0.01-0.22-µF, ceramic -disc capacitor the entire sawtooth waveform C2-25 µF, 25-WVDC, electrolytic capacitor selected for the desired fre- period occurs during a Perfboard materials, enclosure, 6-16-volt,añd 35 -volt power quency range. The value of smaller percentage of the sources, wire, solder, hardware, etc. Cl can range from .005 to total charging voltage. (Continued on page 90) 71

AmericanRadioHistory.Com THINK TANK

By John J. Yacono topic for this month, 1V. It was a "radio" light ate. By virtue of the coating Theabout a new light-bulb bulb. The globe of the bulb and gas mixture, the bulbs technology, was inspired by was removed (apparently it emit a more complete a letter that I'll present wasn't hot) during the show spectrum of light, reducing shortly. It just goes to show to reveal a thread -spool - (perhaps. eliminating) eye you there will always be a like inductor made from strain for those sensitive to RF Bulbs better "mouse trap" waiting heavy -gauge wire (see Fig. other forms of fluorescent

to be invented. Perhaps we 1). I would like to know how lighting. To summarize, they should re -think the wheel? this device works and would are a nearly 100% efficient, After we discuss the func- appreciate any help on longer-lasting, healthier, tioning and features of the this. cost-effective alternative to new light, we'll explore a -Loyd J. Crisp, Metairie, anything else we have. general mix of correspon- LA As for me, I have only one dence, including the I'd be glad to pass along concern about these "super what I know about the new bulbs:" it regards the RF bulbs. However, it is impor- radiation they emit. With all SEALED BULB tant to point out that these the fuss people are making bulbs are in the prototype lately about being inciden- stage and may never be tally radiated (by power - commercially available. As distribution lines, household to the bulb, it consists of an wiring, and appliances), RF transmitter (located in how safe are these small the unit's base) and a RF-transmitters? I don't sealed bulb of gas with an know myself, and I would internal fluorescent coating. appreciate hearing from The sealed bulb has a de- anyone with input on the pression on one side (kind matter. COIL of like a finger -hole in a By the way, this idea is not CAVITY bowling ball) to accommo- totally new It was originally date an inductor on a conceived by Nicola Tesla cylindrical form that pro- who thought it might be trudes from the base, as possible to beam energy you mentioned. The coil directly to bulbs and other couples the RF energy pro- devices without wires. duced by the transmitter to the gas within the bulb. The A WINNER RF BASE WITH frequency, the gas mix- A recent issue told of RF TRANSMITTER ture, and the coating have "one of the simplest" and Fig. I. The small coil been selected so that the also the "simplest" head- transfers RF energy from the RF energy ionizes the gas, light reminder. Well, here is transmitter in the base to the causing the coating to radi- an even simpler "simplest" gas in the bulb. ate light. (see Fig. 2). To install it, sim- The bulb has some great ply tap into the driver -side, "simplest, simplest" head- advantages over other fluo- dome -light switch (which is light reminder, a request rescent designs, let alone a grounding switch) and from one reader answered incandescent units. Since into a positive parking -light by yet another, and advice their are no filaments to line and connect a me- about circuits that have ap- burn out, the bulb's estimat- chanical buzzer to them. To peared here before. Now ed lifetime is about 30 make the connection you let's discuss this new light years. As they don't require will probably need a cou- under the sun. the slightly inefficient step- ple of feet of wire and a up transformers used in couple of connector A BRIGHT IDEA other fluorescent schemes, clamps.

Just yesterday, I saw an they conserve energy and While I have used this 72 interesting new product on are less expensive to oper- circuit for years, my 1990

AmericanRadioHistory.Com Nissan pickup had this - season will be upon us be- warning system from the fore you know it. And as factory. those who live in two -level Go ahead,

-Walt Wheelock, Glen- dwellings (as I do) know, dale, CA when you use air con- put on some weight I've received dozens of ditioning, the upstairs is headlight -reminder circuits often warmer than the in response to the column downstairs due to hot atr that you've mentioned. rising and cool air sinking. In Your's has been chosen to my own case, that situation appear because it is the is aggravated by the ther- simplest one with the high- mostat, which is located est number of good downstairs. As the lower features. Among its dis- level cools more rapidly tinguishing characteristics than the upper level (wth are: one -part design, it lower -level temperature turns off when the door causing the air -conditioner closes to further preserve to shut down prematurely), battery life, and it warns the upper level is always Introducing the improved 372 Circuit Board you even if just the parking unbearably warm. Holder. A longtime favorite for circuit board work, the 372 now comes with our redesigned 300 lights are on. In an attempt to preempt base. A new, patented, internal modification to the 300 split boll locking mecl anism that annoying situation, I allows it to hold twice as much weight os its predecessor. Of course, the 372 still BZ1 have concluded that what I comes with the industry's best circuit board holder, the PanoVise 315, which can MECHANICAL BUZZER need is a way to automat- hold PCBs up to 12 inches wide (up to 28" with 30" 318 Accessory Cross Bars.) TO PARKING ically control a circulating You con even handle multiple board, when you use additional 316 Circuit Board Arms. LIGHT LINE fan so that it cycles on for The new PanoVise 372 Circuit Board Holder. When circuit boards are your business. perhaps ten to fifteen min- TO DOOR LIGHT SWITCH utes every hour, thereby a Fig. 2. Can a headlights -on maintaining consistent reminder get any simpler temperature throughout the 1485 Southern Woy Sparks, NV 89431 (702) 353-2900 FAX (800) 395.8002 than this? If you think so structure. And if a variable then write in. on/off cycle were to be CIRCLE 6 ON FREE INFORMATION CARD designed into the control The other circuits I've re- circuit, so much the better! ceived had one or Iwo of Unfortunately, I'm not the STATEMENT OF OWNE.ISNIP, MANAGEMENT AND CIRCULATION ., tarty aNOMMAYON 2 on or rots those features, but not all of designing kind. But, my POPULAR ELECTRJNICS 1)cA] 9rv46 8 10/15/92 4rn,0u.xYor ISM 1 Anne,.uiZhwul,rto them at once. Since you guess is that such a circuit MONTHLY MICÍ521.95 , comet n...,.ono emotes a ROJO, o or "oruny. ,.,..., o,t o...,o. n.,...u:,.-...u.,...,,.,,,^ were able to distinguish could be built around a 500-B 81 -COUNTY BL/D. FARMINGOALE, NY 11735 yourself from such a large pair of 555's and a relay(?). AI AD MO 02, cr re ..c. 500-U BI -COUNTY BLVD.11711AocuA'TrARMINGDALE, s NY 515 group of readers I've decid- If you think this circuit ed to send you a little could be of interest to your V1t5xLANRY STECI(LERW"y500-B BI -COUNTY BLVD. FARMINGDALE, NY 11735 something extra with your readers, I'd look forward to CARL LnRON rJJW500-8 81 -COUNTY BLVD. rnwIINCOALE, NY 11735 book. It's the special your reply in a future install- MC1010 chip mentioned in ment of Think Tank. .,,..rV.. the first Think Tank column I -Jon Hauko, Acworth, u. + ',AILING . WN wrote, They are hard to find GA _-GEYNSBACY c MT prosemerrnae 12 MY ,-lARRY..STLC:(L i' tAA_n n.e _rri,iYIY-6I.V since Motorola no longer One alternative is to use supports them, so I though something based on the you might like to have the 558 quad monostable timer VAL A COMALM MA ADO little novelty to add to your (see the November and junkbox. You've earned it. December installment of Think Tank for more informa- ,..,n._.2 :Aeáo,n=.,nrn. ° .1sto..e,l.áa7,t .n_r..,.,,u....._..r, IMPROVING tion on that chip). Another 2272CVAAtiON ,s,Te4.on 14 ,:rv. T+EA,. , n

CONDITIONS way to go is to use a limited AntA.nocwi4,n.,^._A 157,684 155,855 First I'd like to thank you version of the circuit pre- e..w,n,,.ran..,.,u...n,,n_e"ew.,r...... _rv, 17,772 51.017 ,.u,r_ ,. ,°., 49,204 49.421 for providing me and many sented by this next reader. u.s..ona..'rv 'CZ o,,. ne 86.976 100,418 other readers with informa- s.r...s.co...iu1n,A , o^Tnsn,n,.c0n.s 4,111 4,285 tion and projects that have IN THE DOG HOUSE 91,287 104.723 often proved to be just This circuit (shown in Fig. ,. a ...... "^.,.,",r n..rva..^..,,.,n r.9:9 6.104 -n^'""°^"^"M"" 60,448 45,028 what I needed. 3) can be used in almost 157,684 155,855 Winter may now be here, any situation to keep the lorOryurMrrw.,..oum.tl.6r,aw.run A. ono.rvrn n,rfio..r,.w,..45rnn.Rmla.e. C../ within 73 but the air-conditioning temperature a cer- ,.,,,.r,.,n+ rn r.r_r.,

AmericanRadioHistory.Com Switch S1 is a mercury Thanks for the informa- _ PL1 switch located in an old tion. The problems you've thermostat assembly that experienced could be due mounted in the dog house. to the fact that you used cg K1 +10VDC You can adjust the parts other than those origi- 10V temperature range by adjusting nally specified in other f the angle of the bulb on places in the circuit. the coil. -14 S1 D1 TJ-- When building your own DOUBLE TROUBLE MERCURY SWITCH IN A 1N4001 control units, make sure I found Andy Barfield's THERMOSTAT COIL ASSEMBLY the contacts of relay K1 exceed Telephone Recording Con- the current draw of the trol circuit (from August,

11 fan(s) and lamp that you 1992, and shown in Fig. 5) MOT2 use. Mine were old comput- and your comments about er -cooling AC fans that it interesting. The reason

NE4 NE3 NE2 NE1 were on hand. Neon lamps that Q2 "doesn't shut itself

MOT 1 COOLING were used instead of noise - ,off by reducing current flow FANS suppressing capacitors for through R3" is that the Q2 no special reason. It just collector -emitter junction Fig. 3. Here's a complete cycling heating and venting system for looks neat when the fans does not achieve full sat- any small enclosed space. go off and the neon bulbs uration. The saturation flash. Just be sure to use voltage will remain just enough neon lamps for above the minimum base - + 9V R2 your fan motor(s) or the emitter forward barrier po- 1K counter EMF will burn them tential of Q2 (about 0.6V). up. That's because the satura- IC The heating lamp, a reg- tion voltage is slightly SOCKET R3 S D 33052 ular 60 -watt light bulb, greater than the sum of the should be mounted in rela- 2 base -emitter forward bar- 0 tion to the thermostat coil rier potentials (about 1.2V). R1 s to give the desired time you The circuit is thus a sta- 27052 í want the area to receive bilized self-limiting linear heat. Mounting it far away amplifier. LED1 C1 + from the thermostat will al- This phenomenon usually 10 ^ low more heat to escape presents a common prob- into the area; mounting it lem when using Darlington - Fig. 4. This circuit can be used to test 555 timer IC's for proper closer will cause the relay pair transistors. For example, functioning. However, does the circuit need to be modified for its to switch on and off more in low -voltage motor-con- own proper operation? frequently. trol circuits, such as in a -Jim Austin, Arlington, IX microcassette recorder, TO TELEPHONE You shouldn't feel awk- which uses only 3 volts, the LINE ward about your circuit. high saturation voltage of o o BR1 Your wife had a good idea 02 could result in a slowing RING(- TIP (+) 1 AMP R3 02 100PIV 1K MPS5172 that another reader will of the motor, and distorted benefit from. Your book is sound on playback. It may R2 1MEG R4 on the way. be possible to give Q2 a l vw 1K little extra "boost" to reduce D1 01 SOME MODIFICATIONS the collector -emitter satura- 20V MPS5172 I built the 555 timer tester tion voltage by connecting (Think Tank, October 1991) a large -value resistor be- PL2 shown in Fig. 4, but could tween the positive output of TO not make it work until I the bridge, and the collec- REMOTE Cl PL1 changed R3 from 330 -ohms tor of Q1. 111 C2 .01 TO AUX. 100K .01 to 9500 ohms. All other The value of the resistor parts in my unit are very should be low enough to close to the indicated val- provide Q2 with the extra Fig. 5. This recording control relies on the doubled minimum ues. It now works quite well base -emitter current re- saturation voltage of the Darlington pair to keep from turning off and is very useful. quired for collector -emitter

I really enjoy Think Tank ! saturation of about 0.1 volt

tain range. I use it in a wife made me do it.) It can Keep it up. with a bridge output of 5 doghouse for year-round be easily reconfigured to -Howard Fogle, Ka- volts. However, it should not 74 temperature control. (My meet many needs. tonah, NY (Continued on page 91)

AmericanRadioHistory.Com DX LISTENING

By Don Jensen here's an easy way, and But logging all con- have operated from this a hard way, to do most tinents-Africa, Antarctica, frozen "bottom -of -the - things. And there is some- Asia, Australia/Oceania, Eu- world" continent, so the thing to be said for each rope, and North and South choices are limited. The approach. As a shortwave America-can also be a easier of the two is clearly Targeting the listener, doubtless you have very difficult task if you limit the Argentine Army's Radio your goals. It may be to yourself to other stations in Nacional Arcangel San World hear as many different sta- those areas, such as low - Gabriel, LRA36, at Base Ant- tions as you can. Or, powered, domestic, or artida Esperanza (which perhaps, the challenge is to home -service shortwave translates from Spanish as tune in a certain as -yet broadcasters. Antarctic Base "Hope"). unheard broadcaster hclf a When it comes to HAC When it is on the air, which it world away. (Heard All Continents), is periodically, it can be there's an easy way, and a heard with quite good sig- hard way. So, for beginning nals at times on 15,475 kHz, SWL and veteran DX'er in Spanish from 2100 to alike, here are some dif- 2300 UTC. ferent ways to accomplish The other Antarctic SW that HAC goal. There are, of station, which has been course, many other stations logged even more spo- that would fit the bill, as radically in North America,

° "VOICE OF THE WORLD" well. The following is just a is the American Forces Ant- sampling: arctic Network station at the AFRICA: U.S. research station at Egypt-Radio Cairo McMurdo. Programming is 7.490 mHz shouldn't be difficult as a mostly local-deejay pop - 41 METER BAND starter. For years, this North - music shows. The frequency African SW'er has been a is 6,012 kHz, and seems best regular on 9,475 kHz during heard from around 100 to the evening hours. You will 1200 UTC when it is active. find it easily if you tune in ASIA: shortly before 0300 UTC, China-Radio Bejing is when its Arabic -music pro- hard not to hear. This is one Y4z1"1611 11 gramming is a dead of the world's major short- giveaway. English program- wave broadcasters, and it ming begins on the hour. operates many transmitters This station sticker is sent, along with a QSL card, to those Angola-Emissora Provin- on many different frequen- SWL's who report hearing WJCR, a new US shortwave station. cial do Lobito, a difficult cies. Look for their English catch, is one of the seldom - programming, which is For many beginning SW heard regional stations beamed to eastern North DX listeners, the self-se- from this southern African America at 0000-0100 UTC lected target is to tune in, country. It has been logged on 9,770 and 11,715 kHz; and then collect QSL-card with Portuguese -language and to western North Amer- verifications from at least programming in the east- ica on 0300 0400 UTC, on one world -band station on ern U.S. on 7,151 kHz at the same two frequencies, each of the continents. around 2230 until 2304 UTC plus 9,690 kHz. While an interesting goal, it's sign off. It relays the Radio Bhutan-Bhutan Broad- not too difficult to achieve Nacional service, but has casting Service, from in this age of super -high- been heard with a local Thimpu (the capital city of powered shortwave trans- identification for Radio this tiny Himalayan king- mitters. With a bit of effort Emissora Regional Lobito at dom), is a prize catch for and some time, one can about 2240 UTC. any DX'er. It has been accomplish that even with ANTARCTICA: heard as far east as On- a fairly unsophisticated re- Well, there are only two tario, however, at around ceiver. shortwave stations that 1300 to 1345 UTC, or later, 75

AmericanRadioHistory.Com on 5,025 kHz. RAI, Radiotelevisione Ital- small religious broadcaster Blvd., Farmingdale, NY AUSTRALIA/OCEANIA: iana, whose English with a big signal, WJCR 11735.

Australia-Radio Aus- - programming is beamed to World Wide in Upton, Ken- Jack DeAntonio of Coral fralia is a good choice, North America at about tucky. Try for this one at Gables, FL, has an opinion since it operates with de- 0100 UTC on 9,575 or 11,800 almost anytime on 7,490 question for me. "What," he cent power from about kHz. kHz. asks, "do you think is the 0000 to 0400 UTC on 21,740 Scotland-There are no Canada-CKFX in Van- most significant thing that kHz; 0400 to 0830 UTC on licensed shortwave stations couver, British Columbia, has happened to SWL'ing in 15,240 kHz, and 0830 to in this northern part of the operates on 6,080 kHz with the past few years?" 1500 UTC on 9,580 kHz. United IGngdom, but there a mere 10 watts of power. It Unquestionably, Jack, it is Bougainville-Site of a are a couple of now -and - is a tough log in most of the drastic and dramatic bloody battle during WW2, then illicit "pirates" on the North America. Your best changes that have oc- Bougainville is part of the air. One whose low -power chance for hearing this one curred in shortwave far-flung island nation of signal has been known to would be during the wee broadcasting within the for- Papua, New Guinea. But jump the Atlantic is hours of the morning be- mer Soviet Union. With the the local inhabitants are in Weekend Music Radio, tween midnight and dawn. disappearance of the old a state of rebellion against which uses different fre- SOUTH AMERICA: monolithic USSR, with its the distant government. The quencies at different times. Ecuador-Flat out, the huge, centrally directed clandestine SW station, One frequency that you easiest way to log South broadcasting apparatus, Radio Free Bougainville has might try is 15,044 kHz on America is HCJB in Quito. shortwave radio has been been heard with some diffi- the weekends at around There is a good chance turned on its ear. culty by North American 0100 UTC. that HCJB will be for most Within the new "com- DX'ers on 3,880 kHz, be- NORTH AMERICA: beginning SWI_'s what it was monwealth," there remain tween about 0800 and United States-While for me nearly 46 years ago, hundreds of high-powered 1100 UTC. there are a number of dif- the first shortwave station SW transmitting facilities EUROPE: ferent shortwave voices that we ever heard. But if you and no central controlling Italy-The choices for an could qualify as easily haven't found it yet, try tun- organization. What we now easy European logging are heard, one of the newest ing 9,745 or 15,155 kHz are seeing are all sorts of many. I've selected Italy's on the air is a relatively between 0030 and 0500 new broadcasting opera- UTC. tions, using the existing Surinam-Radio Apintie stations. Some have been on 5,006 kHz has been an leased to western religious extremely tough logging for broadcasters. Some have more than a few years. It come on the air as fledg- P has been running a mere ling commercial stations. ;; ? NO -CODE 50 watts of power in a noisy There are all sorts of new

1, f`,4 area of the 60-meter band. stations coming on the air. HAM But it was heard not too It's a fun time to be LICENSES ARE long ago in the eastern U.S. SWL'ing! HERE! at around 0400 UTC. It's up to you whether you DOWN THE DIAL All About Ham Radio by Harry Helms, want to try the easy or hard Here are a couple of AA6FW, tells how to get your codefiee path to HAC. eastern European stations ham license and talk to the world. to tune for: In over 300 pages, you'll learn about: IN THE MAIL BULGARIA-Radio Sofia packet (computer -to -computer) radio Your letters are always has been reported with En- ham television using ham radio satellites welcome. What are you glish programming from contacting stations in foreign countries hearing on the shortwave 0300 to 0400 UTC on 9,850, 11,720 and 15,160 kHz. and many other exciting topics explained bands? What are your fa- in a friendly, humorous style without a lot vorite stations or QSL's? Do CROATIA-Zagreb's of math and or technical jargon. If you've you have questions or com- Croatian Radio features En- been wanting a ham license, this is the ments about SWL'ing? Drop glish -language news shortly hook you've been waiting for! me a line in care of DX after 0600 and at 0800 UTC. Only $19.95 at bookstores and radio Listening, Popular Elec- Try 9,830 kHz. They've also equipment dealers. Or order direct from HighText! Add $3 shipping ($4 to Canada, tronics, 500-B Bi-County been noted on 21,480 kHz $5 elsewhere). CA please add sales tax. at about 1200 UTC. U.S. funds only please. *Credits: Dan Ferguson, VA; UKRAINE-The Radio Bob Padula, Australia; Fred Bar- Ukraine. World Service, for- kley, Richard Langley, Canada; merly "Radio IGev," can be IiighTextpublications Inc. Art Magnussen, MN; North heard at various times be- 7128 Miramar Rd.. Suite I5L American SW Association, 45 tween 0200 and 0730 UTC San Diego, CA 92121 Wildflower Road, Levittown, PA 15,195 kHz. 76 19057. on and 17,690

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AmericanRadioHistory.Com HAM RADIO

the receiver to be By Joseph J. Carr, K4IPV rom time to time, I like station (88- to 108-MHz you want to take a look at my band). It seems that he less sensitive to all forms of mail bag and answer some lived only a few blocks from VHF signals (including chan- questions posed by readers. the FM "blowtorch," and it nels 2-5 TV, FM BCB, 6 -meter This "potpourri" usually ram- overloaded the front end of hams, and "low-band" bles from one topic to his receiver. Many modern landmobile VHF -FM com- another, as does the actual receivers do not have terri- munications stations), then Some More mail. But first, however, let bly selective front ends. use a 1V1 filter in the output me say thank you for all of They use a wide bandpass of your transceiver. Potpourri the mail that I've received. filter rather than peaked, However, if you are not With only a couple of ex- resonant circuits (which was able to use such a filter ceptions, the mail has been the former way of doing the because of mismatch prob- in if use running very positive. I am job). As such, some of those lems your rig, or you "wonder -boxes" seem ea- a separate receiver, then SHIELD r -,- ger to overload in the try one of the circuits in Fig. -1 1 presence of strong local 1. Those circuits are 10 - i meter -plus LPF's, and will i L1 L2 signals. .3µH The solution to the prob- probably do the job. You

J1 1 J2 lem is the same as I've can make them small ANT Y RCVR harped on for many years: enough to fit inside many use a lowpass filter (LPF) transceiver cabinets on the C1 C2 C3 C4 with a cut-off frequency (Fe) receiver side of the T/R re- 110pF 110pF 110pF 110pF that's above the 10 -meter lay. L - band, but sufficiently below Of course, with a sepa- A the frequency of the of- rate receiver that's not a fending signal that it is way problem. Build them in an r down the roll -off curve. All outboard shielded box and hams should use some sort be happy. The LPF in Fig. 1A L1 of lowpass filter in the an- is a two -section LC filter that 3.3µH tenna line in order to has a cut-off frequency in J1 J2 prevent TVI from your trans- the 32=MHz region. The ca- ANT 0000 RCVR y mitter (the "good neighbor pacitors (C1 -C4) should be

C1 C2 policy" is best). silvered mica or NPO ce- 7.7pF 7.7pF However, I've seen some ramic -disc units. The cases where a lowpass WI inductors can be either L filter messes up the band- store-bought (try Digi-Key, B pass filters that are used in P.O. Box 677, Thief River Falls, Fig. 1. These two 10 -meter -plus LPF circuits, which are designed the output circuits of mod- MN, 56701-0677; Tel. to remove VHF signals that can cause receiver front-end rigs. As 1-800-344-4539) or made overload, can be made small enough to fit inside many ern solid-state long transceiver cabinets. The LPF in A is a two -section LC filter that as both the output and from Amidon Associates has a cut-offfrequency in the 32 -MHz region. The one in B is input have impedances of (P.O. Box 956, Torrance, CA simpler, but has a less steep roll -off characteristic above the cut- 50 -ohms, and as long as 90508) toroidal cores. Try offfrequency. the entire system is imped- Amidon's T-37-6 (yellow) glad that shortwave lis- ance matched, then the core wound with ten turns teners, monitor buffs, and filter should cause no harm. of #26 enameled wire. general electronics enthusi- But that ideal is seldom The other filter is simpler, asts all find this column so reached in practical cases. but has a less steep roll -off useful. There have been some characteristic above the problems when certain cut-off frequency. It will LOW -BAND VHF brands of LPF's are used nonetheless work for at- SIGNAL'S with some transmitters. The tenuation of FM signals. The One reader complained problems seem aggra- small 7.7-pF capacitors that the 15- and 10 -meter vated when certain should be either ceramic - bands were compromised antenna -tuning units are disc or tubular -ceramic 80 by a local FM broadcasting used in the line as well. If units. The inductor can be

AmericanRadioHistory.Com r l Another "dyn-o-mite" re- also makes sense when the ceive antenna that doesn't pile-up is on one frequency work as well on transmit is (you eavesdrop on the Cl C2 C3 the Beverage antenna. This competition) and the DX .002 .001 .001 J1 J2 claim may seem contradic- quarry is on a slightly dif- ANT RCVR tory because a Beverage is ferent frequency. similar to a long-wire beam To be maximally effective antenna. But the Beverage the second receiver must works best on receive over be at least as good as the poor ground, and is thus receiver in the transceiver. Fig. 2. This HPF filter circuit can be used in cases where AM somewhat lossy for transmit- One recent model that is a broadcast -band interference is a problem. ting. It's not a total bust, very good radio is the R.L. however, and may have Drake (P.O. Box 3006, wound on the same core if it has 5.5-dBi gain on more gain than a dipole, Miamisburg, OH, as above (Amidon T-37-6), transmit, it will also have but it doesn't work quite as 45342;513-866-2421) Model but requires 33 turns of wire. 5.5-dBi gain on receive. The well on transmit as receive. R8. That American -made That's a lot of turns for a transmit and receiver radio receiver walks with T-37 -size core, so use #30 azimuthal and elevation SECOND RECEIVER the best of them, and is a

wire. Alternatively, use a patterns remain the same A little earlier, I men- pleasure to operate. I re- 1-50-6 (yellow) core, wound in both modes. tioned that some hams use cently test drove one and with 29 turns of #26 wire. There is no known case a second receiver on the was most pleased. In cases of AM broad- where the Law of Re- HF bands. Why, you ask? We welcome your letters, cast-band interference, you ciprocity for Antennas is Well, there are several rea- comments, suggestions, etc. can use the circuit of Fig. 2 violated. The only case sons. DX'ers like to keep Send all correspondence to (which I've mentioned be- where it looked like such an track of other DX oppor- Ham Radio, do Popular fore in this column). I've had Earth -shaking breakthrough tunities on the band while Electronics, 500-B Bi-Coun- good results using both the might havé occurred waiting their turn in a pile- ty Blvd., Farmingdale, NY 1-50-2 (red) and T-50-6 turned out to be a hoax. It up. The second receiver 11735. (yellow) cores. In the case appeared in the April issue of the T-50-2 core, only 26 of a popular ham -radio turns of #26 wire are magazine. needed. The Law of Reciprocity an,FCC By the way, when I give does not, however, imply Be wire sizes for filters, the wire that all antennas are "cre- size is for reference only. ated equal" in regaras to The filter will work the same the receive and transmit LICENSED ELECTRONIC TECHNICIAN!, with other wire sizes if you modes. It can be argued can get the right number of that the major antennas turns on the form. It's the (dipoles, yagis, quads, and s, .: turns count that counts, not verticals) are pretty nearly the size of wire (except in matched with respect to Earn up to $30 an hour transmitters, where high receiving and transmitting. and more! power is involved). But that is not universally the Remember, these filters case: For example, the Learn at home in spare time. No previous experience needed! are for receiver applica- small loop antenna is great for No costly school. Na commuting to class. tions only. The higher power small-space reception The Original Home -Study course prepares filters needed for transmit- of low frequencies (75 - you for the "FCC Commercial Radio- ters use heavier duty meters down to VLF), but telephone License." This valuable license is your professional "ticket" to thousands of transmits capacitors and much for squat. I've used exciting jobs in Communications, Radio - heavier inductors. a 24 -inch square loop to TV, Microwave, Maritime, Radar, Avionics and more...even start your own business! cut down the crud on 75 - You don't need a college degree to qualify, WHAT'S THE "LAW OF meters by nulling out some but you do need an FCC License. RECIPROCITY?" of the interference. That No Need to Quit Your Job or Go To School This proven course is easy, fast and low Well, it's not some flaky scheme works well when cost! GUARANTEED PASS You get your New Age concept (George the interference is arriving FCC License or money refunded. Send for FREE facts now. MAIL Gurdieff notwithstanding), from an angle that's dif- COUPON TODAY! but rather a property of ferent from the desired commaND PRODUCTIONS antennas. The "Law of Re- station (it doesn't work well FCC LICENSE TRAINING, Dept. 100 P.O. Box 2824, San Francisco, CA 94126 ciprocity" concept means at all if your location lies in Please rush FREE details immediately! that an antenna works on a line that also passes NAME receive exactly as it works through both the interfering ADDRESS CITY STATE ZIP on transmit. In other words, and the desired station). 81

AmericanRadioHistory.Com SCANNER SCENE

By Marc Saxon adio Shack's Realistic This new mobile scanner If the 800 -MHz band sta- Patrolman PRO -2026 sells for $199.95, and can tions that you most want to kicks off the new year with be seen at your nearest hear are in only one direc- a field goal. It consists of an Radio Shack. We were very tion, then stick it on your attractive mobile scanner impressed with the roof aimed in that direction that reprises a feature we PRO -2026 and found that for long-range reception. A Couple of always liked when it was the service -search feature Or you can mount the yogi available-service search. was a much used function on any TV antenna rotor Winners Pressing one of the five at our installation. We also and then aim it in the many front -panel buttons marked liked that the light in the directions that suit you. This POLICE, FIRE, AIR, WEATHER, and backlit LCD could .be turned antenna really pulls them in MARINE, instantly causes the off, which we appreciated from far away. scanner to begin searching while driving at night. Good The 800 -MHz -band yogi (at 19 channels per second) set! costs $75 (plus $4 shipping), from the Cellular Security ANOTHER Group, 4 Gerring Road, INTERESTING Gloucester, MA 01930. Their PRODUCT toll -free number is For the many readers 1-800-487-7539. ir who are deeply into monitoring the 800-900 - CALLING DR. ¿ Patrolman MHz band, we stumbled SCANNER! '^«.e across something really We have always been of ko.y. , W,, r ,.r r-)61 useful-a powerful, 11 -ele- the opinion that the least OOC,.Vmfy OfiatuW.MI :C. QEALISt)L- ment, rear -mount 800 -900 - monitored local emergen- MHz (only) loop yagi beam cy services relate to antenna for base station medical communications. The new Radio Shack Realistic PRO -2026 offers service search. use. It's fully assembled, so People load up on police all you need do is attach a and fire communications all frequencies assigned to coaxial cable with a Type N channels, but somehow the selected service. You connector to the beam, don't take good advantage don't have to program and feed the signals into of this third partner in local search frequency limits for your scanner. emergency service pro- those services on any viders. bands. Frequencies 155.325, The PRO -2026 has 100 155.355, 155.385, and memory slots, arranged in 155.40 MHz are designated five banks of 20 channels in the U.S. for hospitals com- each. The frequency range municating with is 29 to 54 MHz, 108 to 174 approaching ambulances. MHz, 406 to 512 MHz, and Communications on those 806 to 956 MHz. The cellular channels most often consist bands are locked out at the of the ambulance person- factory. The IF frequencies nel advising the hospital of are 10.8 and 450 kHz. Scan their expected arrival time, speed is 14 channels per the nature of the medical second, with an optional problem of the patient two -second delay for each being transported, the pa- channel. There's also a pri- tient's symptoms and vital ority channel that's sam- Try this 800 -MHz yagi on signs, plus any special med- 82 pled every two seconds. those distant stations! ical conditions that exist.

AmericanRadioHistory.Com 4$ metropolitan areas, un- matters into his own hands. licensed two-way radio He got into his van, which users abound on the busi- was equipped with direc- ness and other VHF tion -finding equipment, frequencies. The FCC is too and tracked down the guy understaffed to adequately who was chopping up his cl. crack down on the prob- frequency with unlicensed lem, and, FCC - besides, chatter. '- 5--- men~-" personnel say they don't After turning in the boot- get paid enough to go into legger, Williams said that it - some of the rough neigh- was the first time in years borhoods where the that he was able to use the .A o bootleg stations are lo- channel without inter- . I : ©xs cated in order to pinpoint ference. Maybe we need - their locations and shut the Green Hornet in every them down. Licensed Iwo - large city. way radio users, neverthe-

- less, complain about their WRITE TO US Scanner owners tend to overlook the exciting medic frequencies. communications being dis- Don't forget, we always rupted by the bootleg look forward to hearing Among the frequencies the mobile repeaters. stations. from you. Our address is commonly used to dispatch Hospitals with helipads In Los Angeles, Van Scanner Scene, Popular ambulances are 155.28, often have 123.05 or Williams (who played The Electronics, 500-B Bi-Coun- 155.34, 460.525, and 460.55 123.075 MHz available (in Green Hornet on TV more ty Blvd., Farmingdale, NY MHz, although others might Canada, 129.275 MHz is than 25 years ago) got fed 11735. Send us your scanner be used in specific commu- popular) for communicat- up with the abuses on the questions, frequencies, pho- nities. Sometimes fire ing with arriving medevac frequency of his business tographs, comments and departments have their helicopters. radio system so he took news clippings. own medical vehicles, and All of those frequencies those might be dispatched should be entered into your on fire -agency frequencies. scanner and checked for Ambulance crews, as well activity local to your area. Enter A World Of Excitement with a Subscription to as medic teams using por- There are other medic fre- table equipment, often quencies as well. You need to send bio-medical should check for activity on Popular Electronics telemetry data. Most often, 33.02 to 33.10, 37.90 to that consists of an EKG sent 37.98, 45.92 to 46.04, 47.46 Get the latest electronic technology and information monthly! to a hospital for quick med- to 47.66, 155.175, 155.205, ical evaluation by a 155.22, 155.235, 155.265, Now you can subscribe to the ll,CREATE A HIGH -VOLTAGE MINIATURE TORNADO physician who can advise and 155.295 MHz. Some fre- magazine that plugs you into on medication to be imme- quencies below 38 MHz are the exciting world of elec- Popular Bleat-des tronics. With every issue of ROW GEAR COMING AT 1llU diately administered. Those shared with stations in the GO y°unM+.RenMnwMO. OM. Popular Electronics you'll find : ,::..^ communications take Highway Maintenance Ra- anon-tech Otero. °, ad.,,. a wide variety of electronics rorur OOGittñRI place on any of eight dio Service. RMCan uwTU projects you can build and " ::,'zmO. M and ..:,;., ..o., channels, known as "MED-1" Although not precisely enjoy. qIRC MARS: limo OR 1116IIUI14 o-" to "MED-8," that run from medical, communications antenna - Pópular Electronics brings 463.000 to 463.175 MHz connected with search and you informative new product (with 25 -kHz spacing), with rescue activities are related and literature listings, feature the mobile and portable to this area of monitoring. articles on test equipment and units operating on paired Good frequencies to tools-al! designed to keep frequencies from monitor for those arrtneqYe0 468.000 to communi- yoú tuned in to the latest NE a ut 468.175 MHz. cations include 122.9, 123.1, developments in electronics. wSSt44,0 , Some ambulance crews 148.15, 155.16, 156.30, So if you love to build fas- Rate have low -power handheld 157.05, 157.175, 282.8, and cinating electronics, just call toll free the number below to transceivers that offer short 381.8 MHz. subscribe to Popular Electronics ... It's a power -house of range. Those units are able Also remember that 47.42 fun for the electronics enthusiast. to communicate with hospi- MHz is the primary Ameri- 1 yr $18.95 2 yrs $36.95 tals only via mobile can Red Cross frequency. (Basic Subscription Rate -1 yr/$21.95; 2 yrs/$42.95) repeaters installed in the FOR FAST CALL TODAY ambulances. The hand- MOVE OVER, BATMAN! SERVICE helds generally use 150.775 It's been no secret in re- 1-800-827-0383 APEAS and 150.79 MHz to input to cent years that in many (7:30 AM -8:30 PM-EASTERN STANDARD TIME) 83

AmericanRadioHistory.Com ELECTRONICS LIBRARY

This two -in -one catalog is to laser, microprocessor, and aimed at electronics enthusiasts telecommunications tech- fowcost as well as vocational and technologies for advanced students. TEST EQUIPMENT- - 1992-93 nical teachers and industrial Each course is designed to lay training managers. Half the cat- a foundation of basic theory and PROJECTS 9-5,- alog is devoted to individual hands-on experience on which YOU CANBUILQ' Educational learning products, the other half students can build as they learn Lady»orar to classroom courses. new concepts and take on real - - YCopszr.em Systems The "Individual Learning life applications. :°w`do, Wd Products" section of the catalog Highlighted is Heathkit's new Catalog offers courseware, training hard- Version 2.0 of their computer - DEuoNrNORYr,4 ware, computer software, aided instruction series of elec- from Heathkit Educational software applications training, tronics training courses. Using Systems and other high-tech learning the power of PC's to make products. Subject areas include learning electronics easier and rectly suit their specific Edited by: Teri Scaduto Electronics, Computer -Aided In- faster than ever, the courses are applications. The book shows struction; Lasers, Fiber Optics, available in the topics of DC how to build a voltage range and Data Communications; IC Electronics, AC Electronics, detector, a digital frequency Semiconductor Devices, and meter, a logic probe, an audio Electronic Circuits; soon -to -be - sinewave oscillator, a sweep sig- released computer -aided nal generator, and several other courses include Digital Tech- essential pieces of test equip- niques and Troubleshooting. ment. All of the projects can be The 1992-93 Educational built using readily available Systems Catalog is free upon components, at a fraction of the request from Heath Company, cost of buying equipment. Marketing Department, P.O. Low -Cost Test Equipment A Box 1288, Benton Harbor, MI Projects You Can Build costs 49023; Tel: 1 -800-44 -HEATH. $13.95 and is published by TAB z CIRCLE 91 ON FREE Books, Division of McGraw-Hill x x / I INFORMATION CARD Inc., Blue Ridge Summit, PA 17294-0850; Tel. 1-800-822-8138. LOW-COST TEST CIRCLE 98 ON FREE INFORMATION CARD IL, d EQUIPMENT PROJECTS YOU CAN BUILD by Delton T. Horn s-.. YOUR QRP OPERATING Budget -minded hobbyists and COMPANION woir+,cov rot hnr áácR, 0 technicians-in fact, anyone by Brad Wells, KR7L dactiordta and comvulan o.coomdPwu ro 1 actual who works with electronic cir- hSloFt6cI1 D,^tir%- 9r>adra trio Madan. Laming cuitry-will appreciate the The hobby of QRP-ham oper- . Products money -saving projects pre- ating with an output power of 5 sented in this book. Included watts or less-is both challeng- are easy -to -follow plans and ing and exciting. Most amateur Electronics and Op -Amps; and practical instructions for building radio contests have a QRP en- Beginning Electronics. Also of- more than two dozen inexpen- try class, and hundreds of hams fered are instructional video sive analog and digital test from around the world partici- tapes; software; test equipment instruments. Projects include pate. In fact, many hams have and tools; weather instruments equipment for monitoring/mea- managed to work more than 100 and clocks; and assorted suring voltage, resistance, countries QRP to QRP. Heathkit projects. capacitance, conductance and This book is designed to help The "Classroom Learning frequency. Specialized modifica- QRP'ers get the most from their Products" section covers a wide tions for many of the projects hobby. No special rig or expen- range of subjects, from funda- are possible, allowing readers to sive and complicated equipment the equipment to di- is needed. Taking a firm stance 84 mental electronics for beginners customize

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Radio Shack has entered the available for $699 at Radio multimedia interactive market Shack stores nationwide. VIS with the Memorex MD -2500 software titles range in price Video Information System, or from $29.95 to $79.95. For VIS. The VIS unit, which con- more information, contactRadio 1.0.1 TO, GOO :aiPLEVPUP,I. s,,., ..,t SI º º nrc m vw nects to any TV set and can Shack, 700 One Tandy Center, rc also be hooked up to a stereo Fort Worth, TX 76102. «Cs system, plays interactive VIS CIRCLE 102 ON FREE Video discs.that provide electronic ac- INFORMATION CARD cess to reference books, The Model SDP -600 auto- Information instructional materials, learning oatch is available at an and action games, and a variety PERSONAL AUTOPATCH introductory price of $199.95. System of educational programs. A For more information, contact j- wireless controller allows users j -Corn's Model SDP-600 Sim- Com, Box 194, Ben Lomond, to interact with the pictures, plex/Duplex Smart Patch is a CA 95005; Tel: 408-335-9120; voice, music, and animation se- microprocessor -controlled inter- Fax: 408-335-9121. quences contained in VIS face between a VHF/UHF CIRCLE 103 ON FREE applications. The system pro- transceiver and a telephone line INFORMATION CARD that allows the user to make and receive telephone calls from any H/T or mobile rig DC POWER OUTLET within range of the base station. Installation consists of con- If you need a neat and easy way necting the autopatch to the to distribute 12VDC to various rig's microphcne and speaker transceivers and accessories, jacks and plugging in an RJ-11 the MFJ-116 Deluxe DC Power telephone.jadc. Control and pro- Outlet might be the solution. gramming is done by DTMF The multiple DC power-outlet tones issued from the remote. strip features eight terminals for Separate user -programmable connecting rigs and keyers, access password codes can be TNC's, tuners, and other gear. set up for local and long-distance dialing. An external logic output, which can be used to control a repeater or to drive a el-Q-4-42a é relay for the control of any ham - - é é é vides high -quality pictures with shack accessory, is provided. color resolution of up to 16 An automatic CW (Morse code) million colors. Its audio system, identification transmission oc- which can be connected to a curs at the beginning and end of Output voltage is continuously home stereo system using op- each call. monitored on its built-in volt- tional cables, is digitally The SDP -600 can be used in meter, making it a handy power synthesized and provides digital full duplex mode with a dual - outlet for electronics hobbyists, stereo sound from both VIS band transceiver. Using full du- too. The MFJ-1116, which can discs and audio CD's. plex, both parties can hear each be installed at the rear of a desk The MD -2500 comes with a other at the same time. Simplex to eliminate the tangle of "hay - VIS version of Compton's Multi- mode may also be used with wires," features eight outlets media Encyclopedia, which VOX control based on sampling with heavy-duty, five -way bind- includes all 26 volumes plus a both the telephone and receiver ing posts with standard spacing complete Webster's Intermedi- audio signals or with optional for dual banana jacks, The out- ate Encyclopedia on one disc. A carrier detection. Turn -around lets are also RF bypassed. The "Save -It" cartridge is included beeps indicate the end of each strip also has a master power for saving game scores or pre- transmission. switch and a 15 -amp fuse. serving electronic "bookmarks" With the reverse patch option The MFJ-1116 Deluxe DC in reference books. Options in- enabled, incoming calls will Power Outlet costs $44.95. For clude a second, wired, hand cause a short ring -out over the additional information, contact controller, and a modem for air. The user then can answer MFJ Enterprises, Inc., P.O. Box connecting to on-line informa- the call using his access pass- 494, Mississippi State, MS tion services. word code. Ring -out activation 39762. The Memorex MD -2500 VIS can be adjusted from one to CIRCLE 104 ON FREE system (Cat. no. 16-376) is nine rings. INFORMATION CARD 87

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AmericanRadioHistory.Com r THE CODE MAKERS BUILD A WIRE TRACER (Continued from page 64) (Continued from page 46) FUN WITH ELECTRONICS 9 -volt battery, then connect a clip r" Coil t)ovianend lead to the closed -loop J2, Conetnroticn 160-COIL DESIGN & output, MnnWd CONSTRUCTION MANUAL and power up the circuit. Turn on a .... $5.95. How to make RF, IF, small AM il audio and power coils; chokes receiver and position it close and transformers. Practically to the clip lead. Tune the radio until every possible type Is discussed. you hear a buzzsaw-like sound, and then adjust the tuning for maximum signal strength. (The maximum transfer of energy occurs when the radio's PCP113-THE PC MUSIC HANDBOOK .... 513.95. internal ferrite is loop positioned per- Learn the basics of computer pendicular to the wire). music systems. For the professional musician, gifted am- Once that is done, connect the op- ateur or 'ust plain curious. posite end of the clip lead to the common output, J3, and note the increase in signal strength. The increase BP297-LOUDSPEAK- ERS FOR MUSICIANS ---- in signal strength is due to circulating $6.25. Loudspeaker design current within from the musician's point of the closed loop. (Any- view! All you need to know, time a closed loop can be used, the and you should be able to design your own after reading signal will be greater and, in most this. cases, easier to track.)

- - Now plug the McTrak into a 117 -volt BP277-HIGH POWER l High Power The first Morse telegraph of 1835 didn't . AC outlet cnd try to trace the McTrak AUDIO AMPLIFIER CON- A1.d40Ampufier Cone/fiction use a key! Instead it Used a 'porirule," signal through the AC wiring using the STRUCTION ..-. 56.25. Here's background and practical de- which was a wooden stick with a groove AM receiver. If the wiring happens to sign information on high power designed to hold small lead blocks. go behind a metal panel in the wall or audio amplifiers capable of 300. ¢00 watts r.m.s. You'll is run through a metal conduit, the find MOSFET and bipolar out- Before long, metal will put transistors in inverting and telegraphers were attenuate the signal, possi- non -inserting circuits. adding hacksaw blades and addi- bly making it too weak to follow. When tional contacts to make dots auto- that happens (or if the signal is dimin- matically when the handle was pulled ished for some other reason), try con- O BP302-A CONCISE USER'S GUIDE TO LOTUS to the right. Horace Martin refined the necting the open -loop output (J1) to 1-2-3 RELEASE 3.1 ....56.25. idea and patented the if If you are a PC user and want the famous conduit and see the signal can to upgrade to Lotus 1-2-3 re- Vibroplex. That semi -automatic key or be traced along the conduit. lease 3.1, this book can teach you how to do that in the short- "bug" was the standard for high- Using McTrak to trace your auto's est and most effective way. speed telegraphy from the 1890's until electrical wiring is just as easy. With all the end of World War II. They're still of the electronics in it's today's cars, BF298-A CONCISE IN- ,Kmew popular, and in recent years old units almost impossible to visually trace a TRODUCTION TO THE MAC- orae++. INTOSH SYSTEM AND have become something of a collec- wire from one location to another FINDER .... S6.25. This intro- tor's item. However, if you are not a without going through maze duction for those new to the a of ca- Mac, this book also serves as collector, and don't wish to pay col- bles, and possibly becoming side- a quick refresher for experi- lector's enced owners that have not item prices, the Vibroplex tracked. But McTrak can handle that used the machine in some Company is still very much in business. task as well. time. The development of vacuum -tube To trace your auto's wiring, connect MAIL TO: Electronic Technology Today, Inc. logic circuits in World War II made McTrak's the J2 output to the wire you P.O. Box 240 electronic keyers practical. These key- want to follow. Then track the signal by Massapequa Park, NY 11762-0240 ers would make automatic dots or moving the radio along the path that SHIPPING CHARGES IN USA AND CANADA dashes depending on which way the produces the strongest signal. If the $0.01 to $5.00 ... $1.50 $30.01 to $40.00 .$5.50 lever was pushed and their receiver's is speed signal too weak, connect $5.01 to $10.00 ..$2.50 $40.01 to $50.00 .$6.50 could be adjusted by a knob. The ear- the common lead (J3) to the car's $10.01 to $20.00 .$3.50 $50.01 and above . $8,00 $20.01 to $30.00. $4.50 liest models were crude but soon self - ground system (negative battery ter- SORRY, No orders accepted outside of USA and completing dots and dashes, memo- minal or chassis in most vehicles) to Canada ries, iambic keying, and many other increase the signal strength. Since Total price of merchandise $ features became commonplace. To- there are some circuits in a car's elec- Shipping (see chart) $ day, many operators are using com- trical system that could be effected Subtotal $ puters and keyboards Sale Tax (NYS only) $ to send Morse, by the full output of the Tracker, it Total Enclosed $ or a variety of other codes, with would be better to always use the speed, code type, and more selecta- closed Name -loop output when working Address ble at the touch of a key. with automotive electronics. City State Zip

AmericanRadioHistory.Com oscillation to cease al- CIRCUIT CIRCUS together. PARTS LIST FOR THE (Continued from page 71) TIME -DELAY CIRCUIT TIME -DELAY CIRCUIT RESISTORS over 25 µF, Frequencies Our next entry, shown in (All fixed resistors are 1/4 -Watt, 5% units.) greater than 50 kHz are Fig. 5, places the UJT in a R1 -4700 -ohm possible when using smaller time -delay circuit. With S1 R2 -100 -ohm=

capacitor values for Cl. and S2 in the normally R3 -27 -ohm :_ Transistor Q3, configured closed position, 01's emitter R4-47 ohm as an emitter -follower am- and C1 are tied to circuit R5 -270 -ohm plifier (which provides a ground through the two R6-1-megohm potentiometer voltage gain of 1) is used to switches and R2, a 100 -ohm ADDITIONAL PARTS AND MATERIALS buffer the output signal, so resistor. Switching either S1 Q1 -2N2646 or unijunction transistor that the circuit can be used or S2 to an open condition SCR1-6-amp, or less, silicon -controlled rectifier to drive a low -impedance allows C1 to begin charg- CI -25 µF, 25-WVDC, electrolytic capacitor C2 -0.1-µF, ceramic -disc (under 1 megohm) load. ing through R1 and R6. If Only very high impedance the switch remains open Si, S2-Normally closed sensor switch Perfboard materials, enclosure, alarm sounder, 12 -volt power loads may be connected longer than the RC time source, wire, solder, hardware, etc. directly to the sawtooth out- period, 01's emitter will put at the UJT's emitter. reach the trigger point and Almost any loading at Q2 fire. When that happens, will cause the output level the positive output pulse at and frequency to drop, or B1 turns on the SCR and the PARTS LIST FOR THE RF SNOOPER +12V

R5 SEMICONDUCTORS R6 27052 Q1 -2N2222 general-purpose NPN silicon transistor 1MEG ALARM SOUNDER Q2-2N2646 or similar unijunction transistor 1M CIRCUIT Q3 -2N3904 general-purpose NPN silicon transistor R1 R2 01 Dl, D2-1N914 small -signal silicon diode 4.7K 2N2646 10052 RESISTORS NAI R4 9)1 SCR1 1/4 5% 4752 6A (All fixed resistors are -watt, units.) VN R1 -2200 -ohm R2 -ohm = C1 -330,000 25 R3 -ohm C2 -470 / R3 R4-3300 -ohm S1 S2 2752 R5-47 -ohm NC NC -o o-o o R6 -270 -ohm R7 -25,000 -ohm potentiometer Fig. Here UJT is used in a time -delay circuit. The time CAPACITORS delay afforded by this circuit can be varied from about one Cl, C4 -0.047-µF, ceramic -disc second to over 30 seconds by adjusting R6. C2, C3 0.01-µF, ceramic -disc C5 -0.22-µF, ceramic -disc ANTI + 9V ADDITIONAL PARTS AND MATERIALS SPKR1-Miniature 16 -ohm speaker R1 ANTI -19 -inch or longer telescoping antenna 2.2K TC1.-. Perfboard materials, enclosure, knob, 9 -volt power source, wire, .047 solder, hardware, etc.

R2 R4 330K 3.3K 444- )F--- alarm sounder is activated. stituted for C1, the time D1 C2 Even if the switch is returned period can be increased to .01 1N914 to its normally closed posi- well over one minute. The 01 alarm sounder may be re- =1N9D214 03 tion, the alarm sounder will 2N2222 2P13904 remain activated until the placed.with a relay or R5 circuit's power is inter- optoisolator/coupler to C3 R3 C4 4752 rupted. control just about anything. li-. 047 .01 47052 The time delay can be varied from about one sec- RF SNOOPER ond to over 30 seconds by A handy little RF snooper, Fig. 6. In this handy little RF snooper, the UJT is configured as a adjusting R6. If a using the UJT as a voltage - voltage -controlled oscillator. As the RF signal strength increases, good oscillator (VCO), the output frequency of the voltage -controlled oscillator quality low -leakage 100-µF, controlled 90 increases. electrolytic capacitor is sub- is shown in Fig. 6. In that

AmericanRadioHistory.Com circuit, an antenna (ANTI) oortunity to experiment with ANTIQUE RADIO THINK TANK picks up RF signals. That this circuit. The preceeding (Continued from page 66) (Continued from page 74) signal is coupled through -analysis was based upon C1 to the base of Q1, which my industry experience.

is configured as an ampli- the tip. Those brown films be low enough to signifi- I was impressed by the fier. Transistor Q1 amplifies are quite common on early cantly load the telephone simplicity, and usefulness of

the RF signal, and the result- radio equipment, and I've line at the on -hook voltage Andy's circuit. I became in-

ing output signal (at Q1's always assumed that they (48 volts). I would start with terested in electronics

collector) is fed to a two - were grease or tar deposits a 5-megohm potentiome- myself at about his age. I diode (D1 and D2) voltage - from household cooking or ter, adjust for the desired hope Andy chooses to pur- doubler circuit, which out- smoking activities. When re- results, then replace it with sue electronics. It has been puts a positive pulsating DC moving them, Alan points a fixed resistor. (Note that a rewarding career for me output at the cathode of D1 out, one should always use the saturation voltage of for the past 24 years. that varies with the level of a wet process (rubbing with Q2 is also affected by re- -Charles Hardin, San detected RF. steel wool dampened in corder -motor load current.) Clemente, CA

The DC output of the Brasso, as I did, would What was the purpose for Thank you for the excel- doubler is fed to the UJT- qualify) so as to trap the resistor R4? It could be elim- lent analysis. While based VCO. As the RF in- dust. Dry sanding or rub- inated, (shorted) and that examining the circuit myself, creases in strength, the bing processes should might improve saturation of I forgot to double the junc- output frequency of the definitely be avoided. Q2. A 100K resistor should tion potential to get the VCO increases. The VCO Reader Duane Buell be connected across the minimum saturation voltage output is fed to Q3, which (Seattle, WA) responded to base -emitter junction of Q1. for the pair (oops). amplifies the signal to a my musings (September, That would shunt the small That's all the room for level sufficient to drive 1992 issue) about the large leakage current of D1 when now. If you have a circuit, SPKR1. Potentiometer R7 al- circular opening under the the bridge output drops to request, or comment you lows you to adjust UJT- Sky Buddy's main tuning 5 volts, and shunt the re- feel might earn you a "Think based VCO's frequency dial. That hole had been verse leakage current of Tank II" or other book, range. punched, for no apparent the Q1 collector -base junc- please write to Think Tank, The antenna may be any reason, then subsequently tion. Cutoff would then be Popular Electronics, 500-B 19 -inch or longer telescop- filled, during the manufac- assured for Q1. Bi-County Blvd., Farm-

ing antenna. The snooper's ture of the cabinet. Duane I have not had the op - ingdale, NY 11735. sensitivity may be increased theorizes that the cabinet by increasing the value of was manufactured for Hal- R6. That's a good place to licrafters by a metal BIG PROFITS IN experiment to obtain the cabinet specialist such as VIDEO REPAIR!1 best overall circuit perfor- Bud or Par -Metal. The same WORK FRONI HOME -EARN $85 HR! mance. cabinet was sold, in slightly With the tens of millions of VCRs and Here we are again at the different configurations, to Camcorders in use, there currently is a serious shortage of end of our monthly visit. So, other radio manufacturers. trained techs to perform cleaning and repair jobs on these popular devices... until we meet next time, One of those required the Learn how ou can start Your own highly profitable, 'áolt good circuitry. large hole; Hallicrafters Home -Based video didn't. servicing business... If you have some Sky Bud- And since up to 95% of all VCR dy lore that you'd like to and share, Camcorder - be sure to write!. malfunctions 4 -++; Contact me c/o Antique are due to a simple mechanical or electro- Radio, Popular Electronics, mechanical failure, you need not spend 500-B Bi-County Blvd., Farm- months or even years of complicated study before starting paid, ingdale, NY 11735. professional service work! Let Viejo's Training Program show you how!

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AmericanRadioHistory.Com equipped vehicles measure position, in session, weather conditions like fog NAVIGATION SYSTEMS heading, speed, and number of or ice, traffic accidents, construction 42) (Continued from page stops, which is transmitted back by ra- delays, and so forth. In the Ali -Scout dio to the TMC. The California Depart- setup, the up -date map is contained vice Center, police agencies, and ment of Transportation (Caltrans), the in the central computer rather than in various agencies doing highway Federal Highway Administration individual cars. The Central Computer maintenance and construction. Tray- (FWHA), and GM are jointly sponsoring continually calculates a minimum Tek cars themselves provide data by the Pathfinder Demonstration Project trip -time route and transmits that infor- transmitting their speed and location, using 25 specially equipped mation to the in -vehicle unit. If an Ali - which can be used to infer when and Oldsmobiles. Scout equipped vehicle is on the path where the vehicle encounters con- An even larger VHS demonstration to a traffic snarl, the Central Comput- gestion or a traffic incident. project is planned for Chicago starter would guide the driver through an- Travtek also offers an extensive in- ing in 1993. Motorola navigation/route other route that avoids this slowdown. formation database of services and guidance system could eventually be The Ali -Scout system also adjusts traf- attractions and on-line emergency installed in as many as 5,000 vehicles fic -light timing to smooth overall flow help with the ability to communicate in the Advanced Driver and Vehicle throughout the system. (We will be via cellular phone. These include ser- Advisory Navigation ConcEpt (AD- looking at the Prometheus Project in vice stations, hotels, motels, restau- VANCE) program. These will be tied -in more depth in a future issue of Popu- rants, and tourist attractions. The driver with a Traffic Information Center via RF lar Electronics.) is provided information in several for- data -communication links. The Illinois The Japanese are also prototyping mats. First, there are simplified maps Department of Transportation, major systems such as the Advanced of the Orlando area graphically Federal Highway Administration, and Mobile Traffic Information and Com- showing routes plus traffic congestion the Illinois University's Transportation munication System (AMTICS). Like locations, incidents, and services in- Research Consortium are involved in equivalent projects in the U.S. and Eu- formation. A push of a button brings the project. The field -operation tests rope, AMTICS uses elements like on- up another format with information will encompass a 200 -square -mile board navigation systems, traffic - about traffic incidents or available area in the Northwest suburbs of Chi- management centers, congestion re- services in text form. Another option cago. Incidentally, for about two de- routing, and even telephone directo- provides guidance instructions via cades the Illinois Department of ries for services and such. simple graphical cues such as direc- Transportation has operated a very On -board navigation systems tional arrows. extensive and quite successful free- could help all drivers, even those with- On the other side of the continent, way -surveillance and control system out vehicles so equipped. For exam- the Pathfinder demonstration pro- in the Chicago area. Traffic advisories ple, Blaupunkt points out an impor- - gram is already underway in Los An- from this system are transmitted to in- tant fact about advanced driver geles. Pathfinder also uses an on- dividual drivers via updatable over- information systems: Only a small per- board navigation system that in- head and roadside signs, and reports centage of the vehicles have to be cludes a CRT map display that pre- on cable 1V and radio including low - equipped with the systems to have a sents traffic advisories and optimal power roadside transmitters. noticeable effect. For example, if only routes sent to it via radio. Alternatively, Over in Germany, the Siemens' Ali - 1% of all vehicles in a major metro- information can be conveyed by syn- Scout was tested as part of the Guid- politan area were equipped with Ali - thesized voice messages over the car ance and Information System, Benin, Scout, overall traffic flow would be radio's loudspeakers. or LISB for short in German. This is one noticeably smoother. A 10% installa- The on -board system interfaces of many "Smart Cars and Smart High- tion would result in a major reduction with the Los Angeles Traffic Manage- way" projects in the very ambitious in congestion. ment Center that includes the Los An- Programme for European Traffic with geles Traffic Management system. the Highest Efficiency and Unprece- Testing is being done on a 13 -mile dented Safety (PROMETHEUS) project segment along the Santa Monica that involves virtually every European Freeway, considered to be one of the automaker, many suppliers, univer- most heavily used roadways in the sities, and research institutes. LISB used country. The "Smart Corridor" used in 700 vehicles, 250 traffic lights, over the demonstration not only includes 2,000 infrared beacons and covered the freeway, but also freeway feeder 1500 kilometers (932 miles) of Berlin roads and five major arterial streets streets. In the Ali -Scout system, data is that can be used as alternate routes transmitted between cars and the to the freeway. Besides sensors like ex- Central Computer via the IR link. The isting induction loops embedded in degree of traffic congestion is infer- the roadway that measure traffic flow red by comparing actual versus nomi- the Los Angeles TMS uses police acci- nal travel times between beacons. dent reports and information on loca- Information sent from cars is fused "OK, whose idea was it to hang Apples on tions where maintenance is under - with other data such as historical con- the Christmas tree?" 92 way. Finally, sensors in Pathfinder - gestion profiles, whether schools are

AmericanRadioHistory.Com the devices MICROPROCESSORS on the external data bus. The data buffer has three -state con- (Continued from page 62) trols and data -direction controls that are connected to the control -unit. The low and high halves of the pro-

DATA TO gram -counter are registers that con- SYSTEM tain the address of the current instruction being processed. The con- ANALOG ANALOG ANALOG TO trol -unit increments the program - ANALOG INPUT DIGITAL INPUTS DIGITAL LATCH MULTIPLEXER DATA- counter registers and sends its con- (8) CONVERTER OUTPUT tents to the address latches when the LATCH next instruction is to be read or when

START READ more information on the current instruction is needed. MULTIPLEXER The low and high halves of the CHANNEL data -counter are registers that con- SELECTION tain the address where data is located in external memory. They may also be used as temporary registers.

The external control lines "Read, , CLEAR "Write," "Memory," and "Input/Output' come directly from the control -unit's latches. COUNTER ADDRESS PROM DATA> LATCH Next month, we'll look at some in- "DATA READY" struction examples and some special CLOCK LATCH instructions. That should show how all these o CLOCK/OSC separate blocks function together to process instructions. Fig. 4. A simple controller could even run an analog -to -digital data-acqusition system. That is because the task is limited to a series of steps that gets repeated over and over.

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Never before has so much The professional discussions seen on professional information on the art the TV screen in your home reveals how of detecting and eliminating CALL to detect and disable wiretaps, midget electronic snooping devices-and radio -frequency transmitters, and other how to defend against experienced NOW! bugs, plus when to use disinformation to information thieves-been placed confuse the unwanted listener, and the in one VHS video. If you are a technique of voice scrambling telephone Fortune 500 CEO, an executive in communications. In fact, do you know any hi -tech industry, or a novice how to look for a bug, where to look for a seeking entry into an honorable, bug, and what to do when you find it? rewarding field of work in Bugs of a very small size are easy to countersurveillance, you must build and they can be placed quickly in a view this video presentation again matter of seconds, in any object or room. and again. 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