Lew/ K1NDV wrote:
Im looking for a TR switch for breakin cw between my DX40 and Drake
2B. May consider a well built home made one even. Any suggestions
appreciated. tnx 73s Lew -K1NDV


Hi, Lew

I've had good luck with the E.F. Johnson electronic TR switch,
as well as the B&W models 380 and 381B. The 381B is not as convenient,
since it has a band switch.

The Johnson unit looks best for high power operation,
since it uses a TV sweep tube (6BL7), whereas the others
use receiving-type tubes. However, it runs hot and is pricey
on the used equipment market.

Dow-Key made a one-tube electronic TR switch, which is small
and mechanically elegant. (I've got one, but haven't tried it yet.)
It requires an external power supply.

One thing, if you go the electronic TR switch route,
don't forget to include a low pass filter in the coax
between the TR switch and the antenna, because you will
generate TVI otherwise, due to diode rectification
in the TR switch, even if your transmitter itself is clean.

73,
Ed Knobloch