[BC] What are these?

[Milspec390 at aol.com]

Yeah,  51S-1 receiver may be instead a 32Sxxx transmitter, who can 
say? Looka like 51S-1 receiver though. Collins S-Line style 
distinctive, beautiful equipment, prized by all, great stuff if you 
can find it.

S-1 worked well, a bit of a tendency to overload on BCB, but overcome 
w/antler adjustment or companion preselector. Stability good, < 100 
cycles/day SSB.

R-388's & R-390s stability far better, < 10 cycles drift/day, but S-1 
ever so slightly more portable. You could stuff it into a large size 
camera bag.

Nixon's AF pilot used predecessor KWM-1 transceiver to call WASH DC 
when VP motorcade was attacked during late-50's Latin America tour. 
Versatile stuff.

                                 z