I have a friend that built at 4 x 4CX250B PA for HF. When it came to
connect to the valve tops, he drilled a hole in each the anodes and used
four screws. Works fine!
The GS-35 should be even more suitable for such a 'KISS' approach.
Regards.
Mark.
-----------------------------------------------
At 18:20 05/02/2005, jeff millar wrote:
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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Remember: A Texas Gallon is actually less than a UK one!
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