What an interesting bunch of photos. As an aside I'm a retired USN radioman. One of my tours at sea was as a member of the MilDet on board the USNS Albert J. Myer (T-ARC 6), a cable layer ship. Myer was quite an interesting man. Was the father of the U.S. Army Signal Corps, as well as the U.S. Weather Bureau.
Seeing the R-390 HF receivers brought back a lot of memories.