The radio had a frequency operating range from approximately 37.8 mHz to 48 mHz, divided into 18 channels.  The IF frequency was 6 mHz.

Even though it only had "line-of-sight" operating distance, the Marine Fritz was considered a "luxury" radio by the U-boats lucky enough to have one on board.

 

Photo by Bruce Culp

Photo by kind permission of the German Naval Association