On Aug 27, 5:19*pm, Michael Black wrote:
On Wed, 27 Aug 2008, Graham wrote:
Ive seen it proposed that you connect to the valve anode .via a high
voltage cap ...never tried . looked a bit risky with 3/4 kv of rf ..
but i suppose that would prevent the 'suck out' from the pi tank
cct .. the rx would be looking through the cct , as long as the vlave
was biased off .. not too much noise ?

G ..

I thought that was the common form, certainly in homebrew articles
that seems to predominate. *Yet, the commercial ones are likely to
be standalone, so one doesn't have to fuss with the transmitter.

I've never used one, and never given it much thought. *I thought
the suckout issue was when it was connected to the plate of the
transmitter, but that's more likely because the suckout issue
was a common issue with TR switches, and I was more familiar with
connecting it to the plate of the transmitter's output tube.

One thing, it certainly was not uncommon to see articles where
the TR switch included a stage of amplification and a tuned circuit
of some sort.

Also, when connecting to the plate, they'd use a very small value
capacitor, and one article I just checked said to use an even smaller
value for a higher power transmitter. *That's going to cause some sort
of loss, indeed that article mentioned one might need to add a tuned
circuit to the TR switch to compensate for the loss.

* * MIchael *VE2BVW

Yes , that was as far as I went , made a dual gate fet t/r switch, but
it needed a tuned cct , did work on the low z side but was down in
gain ...

G ..