Just submerge if aircraft are inbound, the radar ant will retract automatically.
BTW, it's not hard to press Shift+R at the right time to retract the RA so that it matches the con space. However, it doesn't matter if it is not lined up correctly.
Hang on, just out of interest, what language are you playing GWX in (i.e text language)?:hmm: I want to check the commands.cfg of your language.