[BC] What are these?

[Milspec390 at aol.com]

IIRC, what distinguishes 51S-1 receiver from similar appearing 32S 
transmitters & 75S series receivers is small rectangular Band Window 
immediately above crescent shaped vernier Kcs readout. Stuff to left 
& right looka like SSB/RATT converters.

doesn't this seem a fun set up? Any idea re qth? Under whose auspices 
existed? A just society would require these installations in every 
newly constructed home, and as well, retrofits to those extant - and 
it would pay for them as well.

                                                                                z
paul vincent zecchino
manamanybigfatideas key, fl