[Amps] GS-35b fully-submersed oil cooling

[Jim Thomson]

Date: Wed, 18 Mar 2015 23:53:45 -0500
From: donroden at hiwaay.net
To: amps at 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