Thanks for the good advice from both you and Dave Platt. I'll try
lowering the volume and see if that has any effect.

There's no power save mode or any +5 KHz switch; the radio is very
simple with just a squelch, volume, and transmitting Hi/Lo switch.
And the thumbdials for the frequency. I experimented with the Hi/Lo
switch just to rule that out too.

I took a look inside the radio and it's all discrete components. The
audio even sounds pretty good (to my ears). And I can transmit
packets from my Yaesu VX-2R to the Icoms from within my apartment with
good decoding.

Can I build a simple filter that removes everything except 1200/2200Hz
tones?

Mike