[Boatanchors] B&W TR Switch 381C

[manualman at juno.com]

It's normal. The tube used in the TR switch acts as an RF amplifier to
the receiver. When RF is applied, it just cuts the tube off protecting
the receiver input. With the Johnson TR switches, the noise floor between
roughly 3 to 22 MHz is raised a number of DB's. Below 3 MHz and above 25
or 26 MHz, at least with my Johnson TR switches, they start to act like
attenuators.

Pete, wa2cwa

On Thu, 14 Aug 2014 11:37:06 -0400 "David C. Hallam"
<dhallam at knology.net> writes:
> I have a B&W 381C TR switch that has been sitting on the shelf after 
> I 
> purchased it at a ham fest several years ago.  I tried it out for 
> the 
> first time today on 20M with my 73S-3 receiver.  The noise level at 
> my 
> QTH was running about S-3.  When I put the TR switch in the line and 
> 
> peaked its tuning, the noise was about S-7 or 8.  Is this normal or 
> does 
> it indicate a problem with the TR switch?
> 
> David
> KW4DH