Date: Wed, 18 Mar 2015 23:53:45 -0500
From: donroden@hiwaay.net
To: amps@contesting.com
Subject: Re: [Amps] GS-35b fully-submersed oil cooling
A properly designed system would have a sump where the water would
naturally separate from the oil, and a valve to drain the small
amounts of water collected over time.
Don W4DNR
### The problem with oil immersion...which is used on some eimac tubes per the
Eimac catalog is..... if you install a metal tub surrounding the tube... you
now have
stray C from the enclosure to the the anode....which can affect the PI net on
the
upper bands. RF parts used to sell a metal chimney..with a teflon ring on
top, for
the 3CX-3000A7 tube..for air cooling. It added 10 pf of C.
Tube is 24 pf from anode to grid, measured on a wooden bench.
And when inserted in the socket, rose to 33 pf.
That extra 9 pf is caused by the proximity of the lower anode fins to the
chassis below.
Once the metal chimney was installed, it rose to 43 pf.
## any oil cooling scheme would involve the use of an external oil pump +
external air
cooled radiator. ANY leaks anywhere, and you end up with a real mess on your
hands
Jim VE7RF
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