Bubblehead speak with silver tongue.
Yeah, we're currently fooling around with SJ radar;
http://www.subsim.com/radioroom/showthread.php?t=230804
And the radio transmit is probably affected by the same thing. In real life you wouldn't be able to receive either without the antenna sticking up above the surface (in WW2 that is, modern subs have a VLF gadget) but the game ignores that and you receive messages submerged anyway.
This mod;
http://www.subsim.com/radioroom/down...do=file&id=169
Doesn't work for the SJ radar, but it might possibly work for radio transmissions with some hacking.