HI,
I made a 144mhz Pa with a hoseclamp. On my HF PA i used a copper strap,
you can see it on my webpage. www.on6zg.be
I have an original hat for a gs35b tube, but i haven´t used it in any of
my Pa´s, because it covers a part of the cooling elements. I´ll make a
picture of it when i get my digital camera back from the repair shop.
73 Jan, ON6ZG
jeff millar schreef:
Tomm, George, et al...
If heat expands the anode cooler, it does not cause stress on the the
GS-35b, because the the heat sink is completely above the tube's metal
to ceramic seal.
It took a while to find the page you might have meant...maybe this
one? That design looks over complicated to me, and more applicable to
neutralized 20 dB tubes with handles than with 13 dB grounded grid
triodes.
http://www.somis.org/D-a-11.GIF
Here's some pictures similar to the suggestion to use a hose
clamp...found on http://nd2x.net web site.
The amp I built was for 432 MHz...like this one.
http://www.cworthy.net/kl6m/gs35b/choke.jpg
Other Amps with hose clamps
http://nd2x.net/PA3CSG.html
http://nd2x.net/k8cu/amp-2d1.jpg
http://nd2x.net/vk8rh/6m-grid-mount.jpg
http://www.dg2kbc.de/pics/tube_top_b.jpg
The hard way to do a clamp...maybe Russian original??
http://nd2x.net/ea3axv/gen-2b.jpg
Here's a semi-comercial amp using the stainless steel clamp technique
http://www.pa7ta.com/432MHz%20RF-Deck.htm
In fairness...wb8wju has a neat idea for HF amps...similar to an anode
cap.
http://nd2x.net/wb8wju/5w.jpg
So, I think the hose clamp has enough design examples to show that it
works.
jeff, wa1hco
gdaught6@stanford.edu wrote:
Hi,
The one time I did it...used a stainless hose clamp around the base of
the copper fins and pinched a wire under it.
This is probably a BAD way to do it, because the anode cooler will
expand considerably going up to 250 degrees C! The hose clamp could
result in some pretty big stresses in the tube. Rich Measures' (AG6K)
website has a neat way to contact anode coolers that don't have caps
for the purpose... or even those that do!
73,
George T. Daughters, K6GT
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