On Mon, 25 Jan 2010, cullen wrote:

On Jan 19, 4:04�pm, Edward Knobloch wrote:
cullen K5HAL wrote:
Looking for information on Dow-Key DKC-TR tube type TR switch. I have
one without documentation. I found the box it came in, no
instructions.

Thanks everyone. I had found most of the references. The one piece of
information I did not have in hand was the wire color code. I used
this for years with an HQ-150, CE-20A plus the LA-1. The sheet on the
DKC-TRM did not satisfy my curiosity and my old handbooks are now in
storage.
Now that I have your attention, why is the tube type TR switch no
longer made or used? The idea seems great.
Regards, cullen

Very few people use separate receivers and transmitters.

Few are interested in the sort of break-in that you could get
from a TR switch, they can live with relay changeover.

Transceivers sometimes use the same thing, but it's done with
semiconductors not tubes.

Michael VE2BVW