[Boatanchors] 4-1000A coloration ?

[Richard Knoppow]

----- Original Message ----- 
From: "Rob Atkinson" <ranchorobbo at gmail.com>
To: "Jim Wiley" <jwiley at alaska.net>
Cc: <boatanchors at mailman.qth.net>
Sent: Monday, January 02, 2012 2:05 PM
Subject: Re: [Boatanchors] 4-1000A coloration ?


if you do it right you can degas them.


rob
k5uj

     I am curious what method you use. My understanding is 
that Eimac uses a special vacuum pump to create a very 
thorough vacuum when the tubes are made and uses plate 
material that acts as a getter when running at red heat. If 
my understanding is correct the gas will poison the filament 
so that once a tube becomes gassy running it will destroy 
the emmissivity of the filament even if you manage to run 
the tube hot enough to getter whatever gas there is. Now, 
all this may be wrong so I would like to know. There are 
lots of old transmitting tubes around that are structurally 
OK but gassy.


--
Richard Knoppow
Los Angeles
WB6KBL
dickburk at ix.netcom.com