[ICOM] Crossband repeating with Icom radios

[KD7JYK DM09]

: Has someone successfully done something like this?  Are there reasons why
: this wouldn't work as planned?  It looks good on paper, at least.

Yes, many times with many radios for a couple of decades, my first
experiment was a multiband translator for packet radio.  Depending on the
bands and frequencies, you may need to add bandpass and/or notch filters in
the antenna lines, if enough space, you can separate them to prevent issues.
In one instance I had to isolate an audio line with a 1:1 transformer. Audio 
levels for speaker outputs are high relative to a mic input, if your rig has 
a low output audio line for digital modes, use this, if not, you can tap 
into an audio line somewhere in the radio, at the volume control input is 
easy, then a fixed resistor so you can do your thing independent of the 
volume, or use an audio attenuation cable for plug and play.
Check ebay, several people supply pre-made cables to do just this.

Kurt