Doesn\'t look like anyone but you and me are interested in Radios on U-Boats, Ron...I don\'t know very much, and I think I had a link once to a site that had more info, but I\'ve lost it. I\'ll try and answer some of your questions best I can.

U-boats had \"all wave\" receivers, covering from VLF to the upper SW ranges. They had 1 transmitter for the LF range, I think maybe 100Kcs. to about 2 Mcs. and another one for Shortwave. Power output was on the order of 200W. Doesn\'t sound like much, but I\'ve made contact with France and Japan from the Great Lakes region with that much. I don\'t think there was a back-up rig, and there was no VHF or UHF gear on board. I think everything was conducted by W/T, no microphone. I don\'t know if the Torn EB receiver was used on board, but I did see a pix once of a very strange looking rig that was shaped like a coffin and had a large dial drum that was read through a slot in one end of the lid.

I have read that the messages from BdU were sent out on shortwave during the day, then sent on VLF around 10-15 Kcs. at night. The boats did not have to surface to receive the VLF, I read an interview with a former Funkermaat who stated they could hear VLF at almost 100 feet in depth.

I don\'t know if there was much communications between boats at sea. In \"Das Boot\", the radio was not used in the encounter with the other boat, in the movie they used the signal lamp, in the book, flags. Circuit discipline may have had something to do with this, and I think the threat of Huff-Duff took a lot of the gab out of the funkers, too..
Uboats did, however, transmit homing signals when shadowing a convoy for the other boats forming up a wolfpack to find the target. I think these were transmitted in the AM broadcast band, and I don\'t know what form they took.

There is info on this site about the various uhf/microwave radar detectors the boats were equipped with.

Hope this has been a little helpful...