[Hallicrafters] B&W TR Switch

[Mark Shaum]

Peter,

The old electronic TR switches are not really designed to fully mute
your receiver.  They are/were most useful to CW contest folks for
break-in operation, as there is no mechanical T/R antenna relay to then
switch.  A decent boatanchor receiver (with good agc!) would reduce the
local signal on key down enough to allow monitoring of your sig as well
as break-in operation. No go for fone operation unless you like a lot of
feedback!

You can hook the relay contacts from your 32B up to the 115 to provide
for selectable mute on transmit, using the receive/standby switch on the
receiver to allow you to monitor your sig directly if needed.

One drawback to many of the electronic TR switches, they add gain on
receive yes, but that also can reduce the strong sig handling abilities
and increase intermod on receive.  With my Johnson tube T/R switch in
line with the Viking 2 and HQ170, local AM broadcast sigs get combined
in the TR switch and tend to make a mess of the 80 meter band unless an
appropriate tuner is used in-line with the antenna.  The Johnson is a
broad-band untuned unit.  I believe the B&W had a tunable front end?  I
seem to recall it had a bandswitch and tuning control, so it may not
have this problem.

73! - Mark

----- Original Message -----
From: "Parker Buckley" <buckley at iapdatacom.net>

> A few years ago, I bought a B&W 381C electronic TR switch at
> Hamvention.  Still in original box, with directions, appears never to
>
> Have any of you had any experience with these?  The unit seems to work
> fine on receive, providing a little gain as expected.  On transmit,
> however, it does not sufficiently mute the antenna line to the
receiver
> so I get a real blast