International Edition September 1983 $2.49 1/2 Issue #276 Amateur Radio's Technical Journal A Wayne Green Publication Space Shuttle Astro-Hamming Page 8 Teotlhuacan-135 Pyramid Portable Page 135 "10...9...8..." Be ready when the Space Shuttle Columbia carries aloft the first astro-ham. Here's the hest way to contact this historic DXpedition. Report from Poland WA6ITF 8 Page 138 Join the Packet-Radio Revolution Get error-free, high-speed communications. Packet radio's chief architect, WA7GXD, ex- Bake Your plains what it is and how it works. Never Say Die-6 DX-96 WA7GXD 19 FCC-50 Dr. Digital-98 Gift RTTY Loop-102 Be a RTTY Rembrandt Own Apple Subscriptions-67 Letters-102 Put that award-winning shine on your RTTY Page 40 73 Internatioral-70 Awards-104 pix with these tips from a RTTY artist's Contests-84 New Products-106 sketchbook WA20Q1 28 Social Events-86 Reader How to Increase Your QS0s Satellites-89 Service-114 CoCo RTTY! N6HYK's seasoned advice will add spice to Ham Fun!-116 Page 58 your CW contacts—even if you aren't a Help-89, 100, 120 Dealer Novice. N6HYK 34 Corrections-89 Directory-146 Home-Brew an Apple Computer — Review-90 Propagation-146 How to Packet and Save! In this 73 exclusive, KB2GA reveals the Page 19 R7 I-a=" secrets of Apple construction. From key- board to motherboard, it's all here. KB2GA 40 Build This Super Switch The only thing this switch won't do is 6=1 brew your coffee. It's the lazy man's delight K4YS 52 The Amazing Cylindrabola rci This microwave antenna is easier to 6=1 build than a dish But it works just as 09 well WA4WDL 54 Colorful RTTY: An Advanced 0 System for the TRS-80C Its all Ilere —a I U, program, and modem to turn your CoCo into a pro- 4470 65946II fessional-quality RTTY terminal. K6AEP 58 Your Own Apple-40 EOM IC-2W More Features and Powe Per Square Inch! NOW WITH EXTRA NEW MI C--• 11, 1111 1k 1k POWER! NEW GREEN LED '‘ IN THE NEW 25 H MODEL OFFSE' S — , - 3 -5 -9 -20 =° 60 -ii L AS PI" •Fuu.-11 SOW NOR IICOM - . WRITE IC-25A 2" .PPOG-S DUP REV 2 Meter FM Mobile 1 ' ,VOL SOL :" I 25 Watts S/S 4111. PULL ..OW 1 1441": , V IC- R S A Vb - /I The smallest 2 meter FM New HM14 Microphone. mobile on the market is now Smaller and lighter ... the HM14 even easier to read and use microphone provides a 16 with a green LED readout and a button touchtone pad as well ENLARGED HEATSINK compact touchtone /scanning as up and down scan buttons FOR 45 WATTS microphone and gives you the adding easy frequency control option of 25 or 45 watts. of the radio and additional tones for repeater control. NOR/REV Capability. Use of this button in the duplex mode allows one touch monitoring of the repeater input frequency. If II simplex operation is possible you will know instantly. Scanning. Pushing the S/S New Green LED. Easier to button initiates the scan read in bright sunlight, and not circuitry. With the mode switch glaring at night, the IC-25A(Hys in a memory position the unit new readout provides good will scan all 5 memories plus the visibility under all conditions. 2 VFO frequencies. With the mode switch in a VFO position, 5 Memories. Instant access the unit will scan the entire The New 45 Watt IC-25H. The IC-25H has all of the to most used frequencies. VFO A Only slightly longer than its standard features of the IC- band or the portion of the band information is transferred to the companion IC-25A. the IC-25H 25A that have made it the defined by memories 1 and 2. selected memory by pushing the packs a powerful 45 watt most popular 2 meter mobile Full band scan or program band write button. punch. This 45 watts of power scan is selected from the front ever, plus the new green LED eliminates the need for an readout, new HM14 Priority Channel. Any panel and internally switched external power amplifier in microphone and extra power memory channel may be scanning choices of adjustable fringe areas and gives a These new features make the monitored for activity on a delay period after a carrier is savings of space and wiring. IC-25H the best 2 meter sample basis, every 5 seconds, received then resume scan, or mobile value on the market without disruption of a (DSO resume on carrier drop, are conducted on a VFO frequency. standard. ICO M The World S rn ICOM Americo, Inc., 2112-116rh Ave NE. Bellevue, WA 98004(206)454-8155 / 3331 Towerwood Drive, Suite 307, Dallas, TX 75234(214)620-2780 NI stored speoficonons are opproxirnore ond sub)ecr 10 change without nonce w obligonon Al ICOM radios sIgnificonny exceed FCC regulonons lirninng spunovs emsvons 5-STORE BUYING POWER satisfactionUnlike some there'llretailers, be whenno question. Ham Radio YOU OutletCAN COUNTguarantees ON IT! in action' K F NWOO D COMBINATIOLUE NS TS-930S TS-430S NEW!! with Antenna Tuner Buy a TS 430S for TW-4000A Plus FM "Dual Bander" 3 Free Bonus Items $899.95 and select your free package 2m and 70c m in a 1) SP-930 Speaker. from among the following single package! 2) MC-60A microphone. three groups: Buy a TW 4000A for 3) YK-88C-1 filter. 1) MB-430. FM-430. YK-88A S119.85 Value $599.95 REG. $2029 VALUE or and select two of the following 2) MB-430. MC-42S. YK-88 SN. items absolutely free! $1799 S112 85 value or 1) VS-1 Voice Synthesizer. A $230 SAVING 3) Ham Radio Outlet S39.95 value. $90 CASH REBATE. 2) TU -4C sub-audible .s. tone generator. S39.95 value. 3) MA-4000 Duo-band ICO M Mobile Antenna. $44.95 value. N E W!! IC-751 1•1 RETAIL PRICE - a a a .1 PL US FREE SHIP ME NT $1399 — .....1110•••• MINM..11.1.•• ••••• :: (UPS Bro wn) CALL FOR YOUR 0 FOR ALL CO MBINATIO NS SPECIAL PRICE FT-208R \t e gu FT-708R RACI ME B-3016 REG. S239 95 KLM \-1 CALL FOR LOW SALE $199.95 KT-34A PRICES ON HAND-HELDS B-1016 REG $279.95 SALE $299 W-51 and all YAESU ITE MS. SALE $249.95 KT-34XA SALE $799 W-36 • B-108 REG. $179 95 SALE $459 • SALE $159.95 PRICES ARE FOB CALIF CALL FOR PRICE ---------- NE W! EXCEPT FOR CERTAIN • • • ' LM-470D FT-980 B-23S REG. $89.95 COMBINATIONS SALE $79.95 PLEASE INQUIRE CALL FOR PRICE FREE SHIPMENT CONTINE(U.P.S.NBrown)TAL U S A ON MOST ITEMS THAT CAN BE SHIPPED UPS BRO WN SERVING HAMS THERE ARE SOME EXCEPTIONS IN ALPHA. TRI-EX AND KLM BETTER. FREE O ftft North south east. west PHONE U W854-6046 HA M Bob Ferrero,W6RJ 9:30AM to 5:30PM PACIFIC TIME. Jim Rafferty, N6RJ RADIO OVER-THE-COUNTER, 10AM to 5:30PM. other well known hams MONDAY THROUGH SATURDAY give you courteous, CALIFORNIA CUSTO MERS PLEASE PHONE OR VISIT LISTED STORES OUTLET personalized service ANAHEIM, CA 92801 BURLINGAME, CA 94010 2620 W La Palma, 999 1-loward Ave , (415) 342-5757 (7141 761-3033 (213) 860-2040 5 rndes south on 101 from S F Aorport Between Dosneytand & Knott s Berry Farm OAKLAND, CA 94609 SAN DIEGO, CA 92123 VAN NUYS, CA 91401 2811 Telegraph Ave , (415) 451-5757 5375 Kearny Villa Road (619) 560-4900 6265 Sepulveda Blvd . (213) 988-2212 Hwy 24 Downtown Lett 27th ott-ra mp Hwy 163 5 Clare mont Mesa Blvd San Diego Fogy at Victory Blvd AEA • ALLIANCE • ALPHA • AMECO • AR,D-HE • AI., • ASTR ON DAiWP • URAKL • D. L :P.:I. • NIJ,NL P • L ,MILP MINIPR OLAIL ", • kAD A,L • N L • ..,PAAD • ROBOT • ROHN AVANTI • BELD ON • BENCHE R • GER A TEC • BIRD • B & w HUSTLER • HP-GAIN • ICO B • J W MILLE R • KANTR ONICS SHURE • SIGNAL-ONE • TEMPO • TEN-TEC • TIBSTA0 • VOC OM BUTTERNUT •CALLBOOK•cO1 •CCA INK •(. LA, IIK•I-1151-ICRAFT KEN WO OD • KIM. LARSEN • lINAR MT T7 • MPJ • toncRo I OD lATCH anc Poces SpeC thcahons descHpHoes Sublet, to change wirhoot nOloCe Calif testclents please add Sales ter INFO Manuscripts Contributions in the form of manu , scripts with drawings and/or photo graphs are welcome and will be cone sidered for possible publication We can assume no responsibility for loss or damage to any material Please enclose a stamped, self-addressed envelope with each submission Pay- ment for the use of any unsolicited material will be made upon accep- tance AS contributions should be di- rected to the 73 editorial offices How to Write for 73" guidelines are available upon request Editorial Offices: Pine Street Peterborough NH 03458 Phone: 603-924-9471 Advertising Offices: Elm Street Peterborough NH 03458 Phone 603-924-7138 Circulation Offices: Elm Street Peterborough NH 03458 Phone 603 924-9471 Subscription Rates In the United States and Possessions One Year (12 issues) $25 00 Two Years /24 issues) $38.00 Three Years (36 issues) $53 00 Elsewhere: MP-432HL Canada and Mexico —$27.97/1 year only, U S funds. Foreign surface mail —$44.97/1 year only. US funds drawn on U.S. bank Foreign air mail—please inquire To subscribe, renew or change an address: MP-144J Write to 73, Subscription Department, PO Box 931 Farmingdale NY 11737 For renewals and changes of address.