From:aviator@athena.mit.edu (Joakim Karlsson) Subject:Re:Needed:Kenwood TH-26A and TH-46A Mods Date:3 Oct 91 12:50:26 GMT Organization:Flight Transportation Associates, Cambridge, MA Lines:177 Nntp-Posting-Host:e40-008-10.mit.edu What follows below is the most extensive description of TH-27A mods that I have ever seen. Sorry about the ALL CAPS, it came that way. I've performed the "snip-the-green-wire" mod on mine in order to be able to use it for the Civil Air Patrol. Works great. ...Joakim ---- Cut here ---- The following info on the TH27A was posted before, just after Christmas, and is reposted due to recent queries. Please respond directly to the author, Tom, at Internet:N5OFF@W5DDL.AARA.ORG, Packet:N5OFF@K5ARH.#LFTLA.LA.USA.NA I HAVE BEEN DOING SOME EXPERIMENTING WITH MY TH-27A, AND HAVE FOUND IT TO BE AN EXCELLENT AIRCRAFT RECEIVER AS WELL AS A FINE TWO METER TRANSCEIVER. IT WILL ALSO DO FULL 136-174 MHZ TX/RX, BUT I HAVE NOT YET FOUND A MOD CONFIGURATION THAT WILL ALLOW FULL TX/RX AND AIRCRAFT RECEIVE AT THE SAME TIME (EXCEPT THE ASIAN CONFIG, TH-F27, WHICH I WILL DESCRIBE BELOW). WHEN MODIFIED FOR FULL 136-174 TX/RX IN ANY OF THE WESTERN CONFIGS THE AIRCRAFT AM IS DEFEATED (SEE CHART BELOW). IN THE ASIAN CONFIG, THE RIG BECOMES A VERSATILE WIDE BAND RECEIVER 118-174, 200-400 (DISPLAY ONLY) AND WILL TX 136-174. THE PROBLEM WITH THIS CONFIG IS THAT SOME OF THE KEY POSITIONS BECOME RELOCATED (SEE CROSS REFERENCE). THE KEY DIFFERENCES ARE OBVIOUS IF YOU COMPARE A JAPANESE KENWOOD BROCHURE WITH A YANKEE ONE. SO, CAN ANYONE OUT THERE SHED SOME LIGHT ON HOW TO GET FULL 136-174 TX/RX AND PRESERVE THE RELATIVELY HIGH QUALITY AIRCRAFT RECEIVE PRESENT IN THE WESTERN STANDARD CONFIGURATION? I HAVE INCLUDED BELOW MY SUMMARY OF THE POSSIBLE RESISTOR COMBINATIONS, ALONG WITH A PARTIAL RESULTS LIST.(DID I MISS A RESISTOR SOMEWHERE?) R334 R335 R337 W301 REMARKS O - O O K,P US STOCK CONFIG O O O O E 144-146 TX/RX NO AIRCRAFT O O O - E2 136-174 TX/RX NO AIRCRAFT - - O O M 144-148 TX/RX NO AIRCRAFT - - O - M2 136-174 TX/RX NO AIRCRAFT O O - O X 144-148 TX/RX O - O - US MARS 118-174 RX 142-152 TX O - - - US MARS+ 136-174 TX/RX NO AIRCRAFT - - - O ASIAN STOCK - O O - ASIAN MOD 118-174,200-400 RX, 136-174 TX O O - - 136-174 TX/RX NO AIRCRAFT O - - O NOT TRIED - O - O NOT TRIED - O O O NOT TRIED - - - - ASIAN RECEIVE MOD 118-174 RX, 200-400 RX, 144-148 TX - 0 - - COMMERCIAL 136-174 TX/RX, 5.7 MHZ OFFSET, 150 DEFAULT "O" MEANS RESISTOR OR JUMPER IN PLACE "-" MEANS OPEN THE FIRST SIX CONFIGS ARE SHOWN ON THE KENWOOD SCHEMATIC W301 IS OUR OLD FRIEND, THE GREEN WIRE. TH-27A TO TH-F27 (ASIAN VERSION) KEY RELOCATIONS TH-27A KEY = TH-F27 KEY TONE/TONE SEL CALL/C-SCAN CALL/C SCAN BELL/STEP 3 TALT 3 TONE SHIFT/REV REV/SHIFT MHZ/STEP MHZ (NO F FUNCTION) I HAVE SETTLED ON THE ASIAN MOD FOR MY TH-27A, AND FIND THAT THE BUTTON DIFFERENCES ARE EASY TO LIVE WITH. ALL FUNCTIONS ON THE RIG SEEM TO WORK IN THE ASIAN CONFIG EXCEPT I DON'T THINK THE AUTO-DIALER WILL DIAL A * OR #. NO BIG DEAL FOR ME. IT WILL MANUALLY SEND A # OR * THOUGH. AS STATED EARLIER, THE COVERAGE OF THE RIG IN THE ASIAN CONFIG IS 118-136 AM RX (WITH A REAL AM DETECTOR) 136-174 FM TX/RX 200-400 RX I DON'T THINK THE 200-400 WORKS AT ALL BECAUSE I'VE COMPARED IT TO STRONG LOCAL SIGNALS ON A SCANNER AND HEARD NOTHING ON THE TH-27A. SEE THE SENSITIVITY MEASUREMENTS BELOW. OTHER BUTTON DIFFERENCES NOT MENTIONED EARLIER ARE: TH-27A TH-F27 F1SEC,3 TONE ALT SOUND TONE SELECT F MHZ STEP BAND SWITCH 118/145/340 OTHER NOTES: AUTOPATCH WORKS WELL CTCSS TONES SENT OK, DTMF AND CTCSS SQUELCH WORKS BAND SCANNING, ETC WORKS OK PROCESSORR RESET DEFAULTS TO 145.000 INSTEAD OF 144.000 TX/RX NO PROBLEM ON VHF FM RX AIRCRAFT, GREAT! AS GOOD AS A BEARCAT 100/200, BETTER THAN ICOM 2SAT. THE TH-27A HAS A "REAL" AM DETECTOR/AGC (SEE SCHEMATIC). WISH LIST, FOR SOMEONE ON THE NET TO FIGURE OUT THE MOD TO GIVE 136-174 TX AND PRESERVE THE AIRCRAFT RECEIVE IN ONE OF THE STANDARD US OR WESTERN CONFIGURATIONS. IS IT NECESSARY TO GO TO THE ASIAN CONFIGURATION TO HAVE YOUR CAKE AND EAT IT TOO? SENSITIVITY MEASUREMENTS TH-27A 12/18/90 USING AN IFR MOD 1000S SERVICE MONITOR REFERENCE IS 1 LED SEGMENT LIT 1000 HZ TONE FREQ.SIGNAL MHZMICROVOLTS 1181.7AM 1201.5 1220.9 1240.9 1260.9 1280.9 1300.8 1320.8 1340.8 1360.8 1360.5FM 1380.4 1400.4 1420.3 1440.3 1460.3 1480.4 1500.4 1520.4 1540.4 1560.5 1580.5 1600.5 1620.6 1640.8 1660.8 1680.8 1701.0 1721.3 1741.5 200-400NO RX INSERT USUAL WARNING/DISCLAIMER HERE. DE TOM N5OFF@K5ARH.LA.USA -- -- James Dugal,N5KNX Internet:jpd@usl.edu Associate Director Ham packet:n5knx@k5arh Computing Center US Mail:PO Box 42770 Lafayette, LA 70504 University of Southwestern LA.Tel. 318-231-6417U.S.A. -- Joakim Karlsson | aviator@athena.mit.edu Flying Fanatic in Training | FAA:P-ASEL CAP:Freedo  Amsterdam View Our Stats   CLICK FOR A FREE DOMAIN NAMES HTTP://WWW.YOURNAME.TK FOR YOUR OWN WEBSITE IF YOU CLICK HERE AND YOU CAN VOTE FOR OUR FREE WEBSITES IN THE TOP 100 LIST  WANT A TOP RANKING ? 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