Filters. l'hc FL-:1'1,4 and FL-52A deliver razor sharp select ivi tv. 'A serious IIX'ers delight! 25clHz F1,.5:1,4 and FL-101 optional. The I(-71;; Gneral Coverage Receiver covers all bands. all mtdes and is backed by ICOM's full ontyar \varrantJSat any one THE HF FOR TODAYS ACnV€ AMATEUR. and AMTOR olxrations. ol our four North :!merican Senice Centers. Incsludt~s:*IRi~nd Stacking Rcgistcrs. *3!asirnum Operation Flexibility! The The IC-ili3 turns your dreams into reality! Each 1)andk \'F'O's rct;\in rhc l;isr sclecltd thrw step attenuator cuts multi-station frequc.nc!. nic~lcand filler ctioictl \vhtn overloads. *Built-in AC Supplv. Thr IC-765 changn t~ands.I'nducrs ti,? tpuivalml of is IN) jrrctlnt doty cycle r;~tdfor call 20 \.'I-0s; two Ixr hnntl. (;rrat lor niultiband olxration and sulwrh performance on all IIX'ing! $99 Full!. Tunable Memories. ni(des! *Fully :\utornatic .Antenna 0 Stort. i'requrncy. n~cxlc*:~nd filtrr st~ltu.tians. Tuner. With built-in C'I'[' and memory for IIacli one can Iw rrturncd and,or reprn extremely fast tuning and one-touch opera. ,q-anin~cdindrlxndrnt of VFO olxlra~ions. tion. \Vide tuning range. *C\Y Pitch FirstICOM in Communications .Lleniories 90-9:)also store split 'I'x. Kx frp Control. Total olxbrating comfort and I ! a I ' lli! I 11 ;.,,. bl L O,~l~,,~ii,.~WA 99110M convenience for successful contesti~~gand qucnc'ics. * IOZfz Readout. I'crfcct on-thr ~;;;~;~,~;~;~~!,~~;r~;~~,;;;~;;63 dot frt>qurncyselcrtion for nets. DX skcdt; DN'ing. An iambic. keyr wilh adjusta1)lc I;..) I*ITCK.,~,K I:~AW.W 'wI~.;'!)I Alldnla CIA ~oa84 ICOM CANADA A l?~v~%ionol I(;OM Arnr:r~c;~. Inc , 3071 and data conimunicntion mtdes. *Full sldand weight is also built into thr IC-765! or, ,+,at, unll'c Fl!rhrnora, [i(VCIX ;m C.~nnda QSK Rrenk-in. For 5ulx.r C\\' olxkral ions! ICOM also included *Narrow 500112 CW A,,~1~''~~~!,~,~',~~~~~~~~;~Y~~~'~~~,~~,,~,.~;~~~~.~~~~n~~~*~~~~~~~'~~~"~,,~~~,~,"M fl 101 Group A Food for thought. 127.3 3A , 167 9 h% l(rn.0 I% 131.8 3R 173.8 hA Our ncw Universal Tone Encoder lends its versatility 103.5 1A 136.5 4% 179 9 6B 82.5 Y% 141 34A 186.2 72 to all tastes. The nicnu includes all CTCSS. its well H5.4 YA 110.921. 146 ? 48 192.R 7A ;IS Rilnt Tones. Touch Tones, anti Test Tones. No HU 5 YB 114.8 ?A IS1 4 5% 203.5 MI countcr or test cqilip~ncntrequired to set frequency - Frequency ;~ccuracv.+ .I Hz maximum - 4OT to + 85°C just dial it in. While traveling. use it on your Amatcur Frcqucncies to 250 Hz availnhlc on peci:ll order tr;rnsccivcr to access tonc opcriited systems. or in Continuous tonc \.our wrvicc v;rn to check out your customers' rc- Group R -- -- -- pCi1tcrs; also. us ir piccc of test cquipn~cntto modulate r..TFFT-TONES: TOUCH-TONES: BURST TONES lour Service Monitor or signal generator. It can even 697 I?lW 1fd)O 1850 2150 2400 770 l33h 1650 luM 2200 2450 opcratc off an internal nine volt hattcry. and is av;~ilahlc 852 1477 17(X) 1950 2250 2.W i'or onc clay delivery, hitckeil hy our one year warranty. WI lh33 1750 ?O(M) ?\(XI 2550 IR(W) 2Iou 2350 Frequency accuracy. + I Hz maximum - 40°C to + 85°C till tone\ in Group A ;in11 Group R arc incluiled. Tone length ;~ppro.rtimately3(H) mh. May he lengthened. Ourptit level 1131 to within 1.5Jh over entire range sclcctctl. shorttnetl or cliniinated hy chxnging value of resibtor Scpi~ratclevel adju\t pots ;lntl c>utputconnections for each Model TE-64 $79.95 tonc ( iroup. Ininiunc to RF a Powereil h-30vtlc. unre~ulatcclat X rna. 6 F= COMMUNICATIONS SPECIALISTS [.ow inipctlancc. low tlistortion. aii,just;rhlc sincwave 426 Wc\t Taft Avcnuc. Orange, C"ilifornra 92hh7 ourput. 5v pak-to-peak (X(W)) X54-0547/ Cal~forn~a:(714) 998-302 1 In\tar~t\t;trt-up. Oft' po\itinn ti)r no tonc output. Reverse polarity protcctic>n huill-in. HAM RADIO N4TM1, page 44 W7CSD, page 59 - -- GROUND-MOUNTED VERTICAL ANTENNAS 11 JUNE 1990 W.J. Byron. W7DHD, andF.S. Chess. K3BN Volume 23, Number 6 Microwaves: MICROWAVE BASICS 22 BobAtkms, KA 7 GT Publisher & Editor-in-Chief: T.H. TENNEY, JR.. WlNLB The Weekender: PHASOMETER Joel Eschrnann, KSMLD, and Tom Rehrn. K9PIQ EDITORIAL STAFF Editor: INEXPENSIVE SSB FOR 10 METERS TERRY NORTHUP KAISTC Phil Salas. A D5X Consulting Technical Editors: Marty Durham, NBlH Ham Radio Techniques: WARC 1992 Dav~dMcLanahan, WAlFHB B11lOrr, W6SAI Alfred W~lson,W6NIF Robert D. Wilson. WA1TKH VARACTOR DIODES FROM RECTIFIERS Associate Editors: Hugh Wells, W6WTU Peter Bert~n~.KlZJH Tom McMullen. WlSL Joseph J. Schroeder, W9JUV The Weekender: PRECISION CRYSTAL FREQUENCY CHECKER 44 Michael A Covington, N4 TMI Production Editor: Susan Shorrock Copy Editor: Peggy Tenney, KAIQDG Practically Speaking: SAFETY STANDDOWN Editorial Assistant: Beth McCormack FOR THOSE WHO SERVICE HAM GEAR Editorial Review Board: Joseph J. Carr. K41PV Forrest Gehrke. K2BT M~chaelGruchalla. P.E. THE SERIES SECTION TRANSFORMER Hunter Harris. WlSl Charles J Michaels. W7XC Bob Lews, W2EBS Mason Logan. K4MT Vern Riportella, WA2LQQ The Weekender: ANTENNA TUNER WITH A NEW TWIST . 59 Ed Wetherhold. W3NQN Bob Baird, W7CSD PUBLISHING STAFF Elmer's Notebook: ELEMENTARY ELECTRONICS-WRAPPING Assistant Publisher: UP AC THEORY J. CRAIG CLARK, JR., NX1G Tom McMullen. WlSL Advertising Manager: Marty Durham, NBlH DIVERSITY RECEPTION ON HF DIGITAL COMMUNICATION 67 Advertising Production Manager: Stephen Hall, WM6P Dorothy Sargent, KAlZK Circulation Manager: Susan Shorrock Circulation: Marlon Tuttle Traffic Manager: Phil Alix, NlFPX Book Store: Pr~sclllaGauvin PUBLISHER'S LOG 4 DX FORECASTER 73 Cover photo: Michael A. Covington, N4TMI. BACKSCATTER 9 FLEA MARKET 76 COMMENTS 10 NEW PRODUCTS 8 1 HAM NOTEBOOK 57 ADVERTISERS INDEX 82 READERS SERVICE 82 HAM RADlOMagazine(lSSN0148-5989) ispubl~shedmonthly by CommunicationsTechnology,Inc. Main Street. Greenville. New Hampsh~re030484498 Telephone: 603-878-1441 FAX: 603-878-1951. Subaerlptlon Rates: Unlted States: one year. $22.95; two years. $3895. three years. $4995. Canada and Mexlco one year, $31 00 hM,years.$5500 threeyears.Sl4 00 Anolhercounines onevear $35 00vlasurlace mall only All subscrlptlonorders payable~nU S tunds vla lnternattonal postalmoneyorderorcheck drain on U S bank Internetlonal Subscrlptlon Agents. page 77 M~crot~lmcop~esareava~lablefrom Buckmaster PubllshlngMlneral.Vlrglnla23117 CassenetapesofselectedanlCleSfrOm HAM RADIO areavallabletothe bltndand physically handcapped trom Recorded Per~odicals.919Walnut Street. Phlladelphla.Pann- sylvanla 19107 Copyr~ght1990 by Communicat~onsTechnology, Inc T~tleregistered at U S Patent Ofllce Secondclass poslagepa~datGreenv~lle. New Hampshlre03048-0498andat addlt~onalma~l~ngoffices Sendchangeofaddress ro HAM RADIO. Gmnvilie, New Hampshm 03048-0498 A New Direction I have just returned from what turned out to be my most difficult trip ever to the Dayton HamVentionTM.During the course of the weekend we announced that Ham Radio Magazine had been sold to the publishers of CQ Magazine. It was no fun to meet with many hundreds of you and pass on the news that we would no longer be sending our magazine along each month. But it was a very rewarding experience to listen as you told us just how much Ham Radio has meant to you. It's been an extremely productive twenty-two years and I like to think that Ham Radio has met most of the goals that the late Jim Fisk, WlHR, and I set for ourselves as we embarked or1 our new venture back in 1968. As Jim pointed out in his first editorial, there is a very real danger in just publishing state-of-the-artmaterial rf you first don't give your readers a clear grasp of the current technology upon which the new ideas are based. We have worked very hard over the years to ensure that a Ham Radio reader would be offered this carefully planned balance of information. This will be your last issue of Ham Radio, the last of 268 consecutive regular issues of the finest technical journal ever published for the Amateur. Beginning next month you'll receive CQ Magazine, with the addition of a good measure of the very material for which Ham Radio was so well known-the most competent technical articles and projects the Amateur will find anywhere. Why the change? I began to think pretty seriously about th~sidea a short while ago when Dick Ross, KZMGA, publisher of CQ Magazine, asked if we would be interested in being acquired by his organization. By combin- ing the strengths of each publication, Ham Radio and CQ, the Amateur community stands to gain. Although we both serve the same audience, our two publications have really been complementary rather than competi- tive as far as the reader was concerned. One was heavily involved with the technical side of Amateur Radio, while the other was directed mostly to the operator. Both organizations have their strengths. CQ has more of the support services, such as typesetting and in- house subscription fulfillment, that help a publisher lower costs. Ham Radio has a very strong marketing and direct mail operation that can be used to add to the strength of the whole operation. The HAM RADIO Book- store is unequaled in our industry. It can play an even greater part if it serves the readers of not one but the two strongest independent Amateur magazines, as well as three other CQ Communications monthlies. I would like to thank the many people who have contributed to the succ:ess of Ham Radio over the last two decades.