From n1ist@netcom.com Tue May 2 22:16:40 1995 Received: from nuhub.dac.neu.edu ([129.10.1.6]) by amber.ccs.neu.edu (8.6.10/8.6.4) with ESMTP id WAA01613 for ; Tue, 2 May 1995 22:16:39 -0400 Resent-Date: Tue, 2 May 1995 22:16:39 -0400 Resent-From: n1ist@netcom.com Received: from neu.edu by neu.edu (PMDF V4.3-7 #7628) id <01HQ1KP8A5IQ8Y8PUA@neu.edu>; Tue, 2 May 1995 22:16:32 EST Received: from netcom4.netcom.com by neu.edu (PMDF V4.3-7 #7628) id <01HQ1KQIMHB48X6JCV@neu.edu>; Tue, 2 May 1995 22:17:38 EST Received: by netcom4.netcom.com (8.6.12/Netcom) id TAA25988; Tue, 2 May 1995 19:15:08 -0700 Date: Tue, 02 May 1995 19:15:08 -0700 From: n1ist@netcom.com (Michael L. Ardai) Subject: Resent-to: scotte@ccs.neu.edu To: wy1z@neu.edu Resent-message-id: <01HQ1KP8CAOK8Y8PUA@neu.edu> Message-id: <199505030215.TAA25988@netcom4.netcom.com> X-Envelope-to: scotte@ccs.neu.edu X-VMS-To: IN%"wy1z@neu.edu" Content-transfer-encoding: 7BIT X-Status: Status: RO Xref: netcom.com rec.radio.amateur.equipment:13247 Path: netcom.com!ix.netcom.com!howland.reston.ans.net!gatech!paladin.american.edu!zombie.ncsc.mil!simtel!col.hp.com!fc.hp.com!jer From: jer@fc.hp.com (Jer/ Eberhard) Newsgroups: rec.radio.amateur.equipment Subject: Re: Mods for Icom IC-2GAT Date: 2 May 1995 18:25:51 GMT Organization: Hewlett-Packard/WCSO/CSL, Ft Collins, Colo, USA Lines: 291 Message-ID: <3o5tff$fgi@tadpole.fc.hp.com> References: Reply-To: jer@fc.hp.com NNTP-Posting-Host: jerslash.fc.hp.com X-Newsreader: TIN [version 1.2 PL2] Marcin Roycewicz (u39237@uicvm.edu) wrote: > I am looking for any modifications for an Icom IC-2GAT > for ex. : opening aircraft AM receive and expanded RX/TX The 2GAT does not receive aircraft, nor does it do AM Depending on the serial number, there are several solder pads that need a diode attached to them (one diode does expanded TX 138-174). This was gleaned from the net, use at your own risk: RE:--------------------------------------------------------------------- OUT-OF-BAND TRANSMIT MOD FOR ICOM IC-2GAT HANDHELD 2M TRANSCEIVER Back side of display board: _____________________________________ I D505 \ I D507 D504 ___ \ I ___ ___ I___I \ I I I___I I___I \ -- + -- I D506 Q506 . . I I I _o_------ _o_ \J I hole for I I___I I I___I \. I on/off-vol I o o I o o I control I I I I__________________ I -----K---------- I I add diode: 1N914 or equiv. I I I Connect diode between top lead of D506 and lower right lead of Q506 as shown. A surface mount diode may be added right of Q506 at \J. note that the .___. are the same trace, while above the J is the center pole.o . Note that this diode is 1906-0336, "-" at bottom, both "+" at top. ___|___ ^ ^ | | . . Notes: D506 may be absent. If not, remove it. Reset CPU if needed. --- A friend did this and his IC-2GAT can now transmit 138 to 178 MHz (no RF power output measurements were made). He did no retuning, and did not have to reset the CPU. He used a tiny axial-lead glass diode, replaced its leads with wire-wrap wire, and encased it in shrink-tube. The operation requires a super-tiny soldering iron. Observe CMOS soldering precautions: Unplug the iron and ground the tip before touching the circuit. ------------------------------------------------------------------------ The 2GAT mod is really... Remove D 504 which is orginally a 1SS196 and replace it with a 1SS184 which is a dual diode. The service manual componet symbol shows the dual diode but lists the 196. More information on the IC-2GAT. To RESET the CPU (and wipe out memory), hold the LIGHT button AND the FUNCTION button while CPU is on, then turn it off, wait a second, and turn it back on. Continue holding the buttons while all the LCD segments display until "46.01" shows (about 1-2 seconds). This puts the radio into 5/10/15/20/25 khz step mode. Its starts in 15 khz steps and other steps in the list may be chosen. I wish 30 khz were in the list. The instructions for the IC-2GE are similar except that you hold down LIGHT and the WR button on top right next to the power switch. The IC-2GAT also performs this same reset, and also enters the 12.5/25 khz step mode. The step starts at 25 khz. When it is set to 12.5 (the only other choice until you reset the CPU the first way) you can dial up frequencies like 146.0125 which shows like "46.0125" where the "25" are BOTH smaller digits. The "5" never shows in the "American mode". The display goes to "46.01" in the "American mode" and to "46.00" in the European mode. Another curiosity is that when I RESET my CPU, I did so while it was tuned to 162.55 (weather). When I turned the power back on, EVERY segment was displayed, but the radio was actually receiving 162.55 anyway. Then when the reset finally took effect, the display went to "46.01" and the weather signal was lost. I also notice that sometimes, the "U" for synthesizer unlock (in the 10's position of the memory number) shows up just at the moment the "46.01" or "46.00" does, then ends in a second. I guess the sythesizer is being reset as well. ------------------------------------------------------------------------ --Phil howard-- For those of you who are trying to interface something to a rig which has a single two-conductor plug for both microphone input and push-to-talk connections, such as many of the handheld rigs including the Icom IC-2AT and IC-02AT, here are three circuits that may be useful to you: ::: Electret condenser microphone to radio: Radio Shack #270-092 mic element? MIC--------------+--------------------O------------> Mic/PTT on radio | | | | | | <-- Shield +------/\/\/----+ | | (20-30K) / <-- PTT | | / switch | +--------------------+ +-----------+------------> Ground on radio ::: Dynamic microphone to radio: MIC +-----------------------O----------> Mic/PTT on radio COIL C | C | C / | <-- Shield | / | +-----------+ +-------+----------> Ground on radio ::: High-level input (such as from tape recorder, RTTY AFSK generator, or Packet TNC output) to radio: HIGH LEVEL OUTPUT: RADIO INPUT: (0.47 uf) Audio to transmitter -------||-------+----O------> Mic/PTT on radio (25K) | | Push-to-talk -------/\/\/------------+ | <-- Shield | Ground -----------------------------------+------> Ground on radio Subject: Hints On Interfacing To Radios Newsgroups: rec.ham-radio,rec.ham-radio.packet Keywords: HT's, packet, RTTY, microphones ------------------------------------------------------------------------ /***** hpfclj:net.ham-radio / ky2d-2!ka2ugq / 12:08 pm Jan 26, 1986*/ I made a big mistake in the previously-posted schematic of the connection between an Icom IC-2A, 2AT, or 02AT and a packet radio TNC, RTTY afsk unit, or another microphone. The resistor and capacitor were backwards. The correct schematic follows: Audio from TNC* PTT Ground | | | --- / | (C1) --- (R1) \ | | / | | | | Icom HT | | | mic input------+-------------+ | | ground--------------------------------+ C1 - 0.47 uf capacitor R1 - 25K resistor * TNC or RTTY afsk or another microphone or whatever you are interfacing to your Icom HT. -Tom KA2UGQ uucp: ..!ihnp4!bellcore!mtunh!ky2d-2!ka2ugq or: ..!ihnp4!bellcore!ka9q!tom packet: KA2UGQ @ WA2SNA-1 bomb: 40 41 N, 74 25 W 2m FM: 145.750 MHz (local simplex) /* ---------- */ >From: needham@XN.LL.MIT.EDU (jim needham) Subject: Re: Re: Which Handheld? Message-ID: <1717@xn.LL.MIT.EDU> Keywords: ICOM IC-A20 alkaline headset-adapter lost-in-the-soup In article <49366@lll-winken.LLNL.GOV>, dralle@roxanne.tmc.edu (Sir Matthew G. Dralle) writes: > > > ...I paid $449 + sales tax for a new IC-A20, $26 for the ICOM > >alkaline battery pack, and $50 (arrgghhh) for the headset adapter > >(Sigtronics, with a yoke mounted PTT switch). If you can find > >the aviation-standard connectors, it would be easy to fabricate > >a headset adaptor and save a few dollars... > Be careful - There is a LOT more to the ICOM PTT switch than meets the eye. > There is no easy way to match up an external mic and the ICOM with out the > PTT unit from ICOM. A couple of jacks and a switch or two isn't gonna do it. > Icom uses a wierd wiring scheem in the mic jack so that if you were to plug > a mic into the Icom directly, you would have to use the PTT *ON* the radio. I .....[ stuff deleted some where in here ] > can't remember the exact wiring now, but without extensive modification and > an additional relay *ADDED* to the PTT cicuit from Icom, you won't be able to > use your standard PTT that you got with your headphones. I hate to be a > downer, but those are the facts... > > Matt Dralle > Serious RV-4 Builder... > dralle@roxanne.llnl.gov Hi, I have been reading this news group for about 5 years now but this is my first post. Sorry if anything gets screwed up with the post. First, I would like to say thanks to all the knowledgable people who have shared their experiences ( the list of names is to long ). Please keep up the GOOD work !! As to the ICOM question of PPTs. I have just finished installing an ICOM in my RANS S-10 with PTTs on the throttle with a Sigtronics intercom. This is how I made every thing play together. Sorry for the poor graphics. ICOM mic plug tip to one side of a normally open push button switch. Other side of switch to middle ring of a standard mic jack. Carry the shield straight from the mic plug sleve to the standard mic jack sleve. Now you can plug either a headset mic or the mic plug from the Sigtronic intercom into it. ___T___ push button switch ^ ^ | | ____________________| |_____________________________ | |___ C IIIII V | n. c. --^ _] |_____________________________________________________| mic plug shield standard mic jack for ICOM OR ICOM mic plug tip to the middle ring of a standard mic jack. Carry the shield straight from the mic plug sleve to the standard mic jack sleve. Now you can put a DC PPT in the standard mic jack and then put either a headset mic or the mic plug from the Sigtronic intercom into the PPT mic jack. NOTE that if you plug a mic or the intercom mic plug into this it will key the ICOM. ______________________________________ | |___ C IIIII V | n. c. --^ _] |_____________________________________| mic plug standard mic jack for ICOM Standard aircraft radios use the tip to shield to key the transmitter, the ICOM does NOT use this method. David Clock PPT switch switches BOTH the mic lead AND the tx key lead, I think some others do as well. Jim Needham N201S work-617-981-2535 ------------------------------------------------------------------------ When I wanted to do this, I started out by making two simple straight through adapters, one for the mic and one for the phone. Then I measured all combinations trying to figure out how ICOM did thier trick. I accidently shorted the mic tip to shield and the tx LCD lit. I also pluged a mic from a headset and noticed that the tx keyed, and having another radio on the bench, heard the feedback. ICOM mic jack, only 2 conductor tip to shield, about 4 or 5 volts phone jack rx, audio from tip to shield tx, same DC as above from tip to shield My installation does work. In the air, on the ground, upside down B-{)### I have also talked to someone else in my plane from another ICOM and it sonded good to me. Hope you have the same good luck that I have had. Stay out of the trees. Jim Needham N201S work 617-981-2535 -- Jer/ (Slash) Eberhard, jer@fc.hp.com, 970 229-2861 OFFICE, 970 229-3598 FAX Hewlett-Packard, 3404 East Harmony Rd MS-E8, Ft Collins, CO 80525-9599 C-182 N182H, CFII Airplane & Glider, FAA Denver FSDO Aviation Safety Counselor, CO-CAP Group 2 Cmdr, MSN CheckPilot, PP218 HAM N0FZD, 26 Young Eagles Flown!