[Amps] Pre-heating of tubes

[R L Measures]

On Jul 28, 2006, at 8:49 PM, GGLL wrote:

> Ian White GM3SEK escribió:
>
>>
>> It also explains why transmitting tubes generally need to be pre- 
>> heated
>> after a long period out of use. The process of slow diffusion to the
>> surface of the materials means that gas will probably have  
>> accumulated,
>> and the getter needs some time at a high temperature in order to  
>> do its
>> job.
>
> 	Very clear explanation, Ian, thank you very much. I want to ask  
> something about.
> 	This pre-heating process (in, for example, NOS tubes or those used  
> in good
> condition but long time stored ones) must also be done by making  
> the anode
> orange hot in high power tubes (those with "gettered" anodes) or  
> it's just
> enough to run them with filament on for many hours?.

Good question, Guillermo.  If gettering really works as claimed  
hereabouts, why do large tubes depend on built-in ion pumps?
>
>
> Best regards
> Guillermo - LU8EYW.
>
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R L MEASURES, AG6K. 805-386-3734
r at somis.org