[Milsurplus] BC-357 Marker Beacon Receiver

[Jack Antonio]

Don't see these mentioned too much.

Just for fun, I powered one up tonight.

After peaking up the tuned circuits, it functioned
as advertised, pulling up its relay at about 700 uV
input at 75 megacycles with 1000 cycle modulation.

Didn't do rigorous checks on it, as I don't intend
to being flying with it.

It has an unusual circuit, one tube (12C8)is both an RF and AF
amplifier with detector, in a reflex configuration, the second tube is
another AF amp and diode (12SQ7) that rectifies the
recovered audio to drive the relay.

The set calls for a VT-153 which is a special 12C8. Not having
one, I used a VT-169, which is a regular 12C8, seems to work.

It would be interesting to know what was "special" about the
VT-153 12C8s.

Jack Antonio WA7DIA/4