Quote: Originally Posted by
colin 
There's a pin at the DIN connector that is actually called PW_ENABLE, and it goes LOW when the unit is on, high when the unit is off. You could use that signal to ground a relay which provides the +12 to your antenna. That way the antenna goes up and down with the unit's power.
Thanks Colin for the idea. I wonder if this pin is populated in Mitch's cable. If so, that could be wired up easily enough.