colubridae's post in comms fail was marked as the answer
thanks rongor
that was the problem.
Batumi in the edit file shows blue.
but there are several red units dotted around the airfield. and the F10 map showed Batumi as red. (i hadn't configured it as red in the mission editor, i don't know how)
as soon as i tried a mission without red units around the airfield then Batumi showed up on the F10 map as blue.
comms then worked as expected.
(even using 'ralt and OEM102' key combo)
