This B&W Model 380 T/R Switch for Vintage Transmitters & Receivers, is in very good condition.
I powered it up on the bench and the tube lights up and everything looks okay inside.
I am selling it as is as described.
It would be prudent to change the electrolytic capacitors before putting it into service.
B&W 380B electronic TR switch Operates as follows.
You use a series UHF coax T-Connector mounted on the "Antenna" terminal
of the TR switch. One end of the T goes to the Transmitter,
the other end to the antenna. The "Receiver" terminal
gets a coax line right to the receiver.
It's also possible to use the TR switch between a separate
receiver antenna and the receiver.
I have no paperwork. B&W advertised it as good for a KW A.M.
on the HF bands.
The 380B uses a single tube, type 6AH6 pentode.
Mine required replacement of the two electrolytic
capacitors in the power supply, and the 1K resistor
from the power supply B+ to the tube.
There's a large bifilar ***under the chassis for the 6AH6
heater line, and a smaller ferrite rf transformer above
the chassis feeding the receiver. The 6AH6 rf amplifier
circuit is untuned. The 1.2 Meg grid resistor
furnished cutoff bias when the transmitter is on.
The coax length between the TR switch and the transmitter should be
as short as possible, to minimize "suck out" effects -
possibly desensitizing the receiver at certain settings
of the final pi network.
Also, the transmitter and/or amplifier should be biased
to cutoff during receive, to minimize noise.