Kg3v Ham Radio Blog

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Cant Use TUNE Button on IC-7300 with KAT-500 Tuner

Posted: 03 Mar 2019 07:02 AM PST
https://kg3v.com/2019/03/03/cant-use...kat-500-tuner/


When I initially connected my IC-7300 to my Elecraft KAT-500 Antenna Tuner,
I was unable to get the Tuner to start Tuning the KAT-500 from the TUNE
button on the front panel. Here is what I discovered:

I was using separate 12 volt power from my Station power supply for the
Tuner. Only the Tune Data connection was made from the AH-4 Tuner Connector
to the KAT-500 (along with RF connections, of course). This seemed to work
fine if I use the TUNE button on the KAT-500, but the IC-7300 behavior was
as if it id not realize there was an external Tuner connected.

In discussions with several others about this, Fred WB4QOC suggested that
maybe I need to use 12 volts from the IC-7300 for the Tuner power. It turns
out that this solved my problem. I did that, and now the TUNE button on the
IC-7300 acts as desired, tuning the KAT-500.

Why did this happen? My guess is that the IC-7300 must see current draw on
the Tuner (AH-4) port 12-volt line, to know that an external Tuner is in
use. Note that this is NOT the case with the IC-7600. I think I have heard
that this is also NOT the case with the 7610, but have no experience there.

In the end, it all works great IC-7300, KAT-500 and KPA-500 Amp.