[ICOM] AH-3 use with Collins KWM-2

[Gary Fiber]

You will have to build such a control circuit. The AH-3 was never designed 
to be used on other vendors products, so no external control box was made 
by icom specifically for the AH-3 tuner.  I used to have a diagram when I 
worked at Icom, the tech support department may still have it. Along with 
the controller you would need to place the radio in a carrier mode such as 
CW, FM, RTTY or AM set the radio output power to NO MORE than 10 watts and 
start the AH-3 through its tune cycle. The start line needs be pulled low 
for about 200 milliseconds, the tuner sees the RF and starts through its 
cycle. When done it stops and stays in the tuned condition until you remove 
power from it. I did a quick google search and did not find the diagram I 
was looking for. Maybe mods.dk will have something.

If you can find an AH-2 tuner, the control box that was supplied with that 
tuner will operate the AH-3 just fine. Over the years I have seen some sell 
the tuner and retain the control box so there maybe some of those floating 
about. The AH-2 control box used a chip as it would place an Icom 735 into 
FM mode for tuning purposes and return it to the original operating mode 
when done with tuning. That was done via the CI-V control system. The AH-2 
control box also feed in an ALC voltage to drop the final output top 10 
watts and pulled the PTT low to start the 735 transmitting. There was a 
real nice write up about the AH-4 tuner operation posted on this list a few 
weeks ago. The AH-2, AH-3 and AH-4 all work the same way so far as 
controlling. Possibly a archive search will help you find out how to 
control your AH-3 to use it with other vendors products such as your 
Collins equipment.

Gary K8IZ

At 05:08 PM 4/21/2005, you wrote:
>Well,  I belong to two Collins groups and no one has ever talked about
>using an ICOM antenna tuner. AND since the modification would have be
>to the ICOM AH-3 to make it run without an ICOM725 not to the Collins
>gear,  I would suppose that the ICOM list would be the best place to
>look for information.  I would have thought there was an external
>circuit that could be plugged into the data cable of the AH-3 that
>would allow external control of the circuitry.
>
>On 4/21/05, Bert Morton <hamradioguy at vermontel.net> wrote:
> > Maybe there is a Collins group ? where you could get an answer...just a
> > thought..
> >
> >
> > ----- Original Message -----
> > From: "Jim Isbell, W5JAI" <jim.isbell at gmail.com>
> > To: "ICOM Reflector" <icom at mailman.qth.net>
> > Sent: Thursday, April 21, 2005 7:55 PM
> > Subject: Re: [ICOM] AH-3 use with Collins KWM-2
> >
> >  Well, I HAVE an AH-3.  So how do I use it?
> >
> > ----
> > Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net
> > Icom Users Net: Sundays, 1700Z, 14.316 MHz
> > Icom FAQ: http://www.qsl.net/icom/
> >
>
>
>--
>Jim Isbell
>"If you are not living on the edge, well then,
>you are just taking up too much space."
>W5JAI
>UltraVan #257
>CAL - 27   #221
>1970 E-Type
>1985 XJS
>1982 XJ6
>----
>Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net
>Icom Users Net: Sundays, 1700Z, 14.316 MHz
>Icom FAQ: http://www.qsl.net/icom/

Gary Fiber K8IZ
GROL PG-19-6691
Washington State Resident