On Thu, 16 May 2013, Tom Dean wrote:

I have a Yaesu FT200M which I have installed in my truck for the purpose
of transmitting an APRS signal on 144.390. Each time I set the radio on
this frequency, turn the radio off and then back on, the frequency
changes to 144.385. Turn it off and on again and it tunes to 144.380,
etc., etc.

Anyone have any idea how to turn this "feature" off so the radio stays
on 144.390 when I turn it on and then off? I've read through the manual
but don't see anything.

Tom, I suspect that there might be a cabling issue that is causing the
radio to erroneously register a push of the "down" button on the
microphone (if that model is so equipped). I ran into a similar issue
with an FT-2800M a few years ago; that model in particular was also
susceptible to erratic behavior from RF coming in through the microphone
line.

I guess the best place to start would be to disconnect your APRS interface
and see if the problem persists. If it goes away with the interface
disconnected, it could be a cabling issue.

Steve
KG4PEQ