Zirconium getters best at about 1000 degrees C, this why large metal anode
transmitting tubes like the 4-400A, 4-1000A, and 3-500 must be operated with
a dull red to red anode color. Zirconium also releases some gasses and
absorbs other gasses at various temperatures. The varying temperature
across the length of the anode (and as the anode heats and cools) allows the
gettering agent to absorb a wide variety of gasses.
You can do what you will but I like to run a little color on my large
bottles.
Dave, W3ST
Publisher of the Collins Journal
Secretary to the Collins Radio Association
www.collinsra.com - the CRA Website
Now with PayPal
CRA Nets: 3.805 Mhz every Monday at 8 PM EST
and 14.253 Mhz every Saturday at 12 Noon EST
Collins Chatroom - Daily at 4 PM EST on 14.285 Mhz
----- Original Message -----
From: "John Lawson" <[EMAIL PROTECTED]>
To: "Discussion of AM Radio in the Amateur Service"
<amradio@mailman.qth.net>
Sent: Monday, December 11, 2006 12:00 PM
Subject: Re: [AMRadio] Screen Modulated 813
On Mon, 11 Dec 2006, david knepper wrote:
John, you better check your copy of Eimac's classic on the Care and
Feeding of Power Amplifier Tubes.
Which edition? I think I have 'em all... ;}
I strenuously re-iterate the point that making a sweeping omnibus
generalization about 'red plates re-adsorbing gasses' is just that: a
generalization, and can be (disastrously) not true in a lot of cases....
Of course, running a 6146 red hot is not acceptable. I was referring to
large transmitting tubes like the 4-400A's, etc.
Y'all didn't say that - you said "...the tube..."
Nit-pickingly yours:
John
KB6SCO
DM09fg
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