On Jul 12, 2005, at 10:15 PM, ad5gb wrote:
>
> Ian has a virus. It's called Microsoft.
That's a terrible thing to say, Randy - even if it is true.
cheerz
>
>
> (sorry couldn't resist)
>
>
>
> --
> Randall D. DuCharme (Radio AD5GB)
>
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> --- On Wed 07/13, < gdaught6@stanford.edu > wrote:
> From: [mailto: gdaught6@stanford.edu]
> To: g3sek@ifwtech.co.uk, amps@contesting.com
> Date: Tue, 12 Jul 2005 21:16:58 -0700
> Subject: Re: [Amps] Tetrodes
>
> Ian, please turn off the bubble machine, or whatever has to happen!
> <br>I've gotten about 10 copies of this message. Or is it just
> me?!<br><br>73,<br><br><br><br>On 12 Jul 2005 at 23:04, Ian White
> GM3SEK wrote:<br><br>> R wrote:<br>> <br>> A great deal, but I don't
> have time to trade the same old one-liners<br>> with him, yet
> again.<br>> <br>> However, the following are genuine questions so I'll
> try to answer<br>> them.<br>> <br>> >> This is a deposit of chemically
> active metal,... ... In larger <br>> >>transmitting tubes the<br>> >>
> getter is usually something like zirconium, which needs a higher<br>>
> >> temperature to function correctly.<br>> ><br>> >Does zirconium
> gettering take place at room temperature?<br>> <br>> The gettering
> (adsorption) reaction that traps the gas goes faster at<br>> higher
> temperatures. Gettering by zirconium does take place at room<br>>
> temperature, but at a very slow rate.<br>> <br>> To complete the
> story, there is also an opposite de-sorption
> reaction<br>> that releases the gas. At normal anode operating
> temperatures,<br>> adsorption goes much faster than desorption so
> there is a net<br>> gettering effect. But at very high temperatures
> the desorption<br>> reaction overtakes the adsorption, so there is
> then a net release of<br>> gas. That is how the tube structure is
> de-gassed during manufacture,<br>> by heating it to a much higher
> temperature than normal.<br>> <br>> >Do 3-500Zs utilize a zirconium
> getter?<br>> <br>> As far as I'm aware, 3-500Zs do have a zirconium
> getter on the plate,<br>> so it works well when the plate is hot. In
> answer to Vic's question,<br>> that does seem to imply that those
> tubes need to be run with some<br>> plate dissipation if there is a
> need to clean up the vacuum... but I'd<br>> defer to anyone with more
> practical experience.<br>> <br>> <br>> -- <br>> 73 from Ian G/GM3SEK
> 'In Practice' columnist for RadCom (RSGB)<br>>
> http://www.ifwtech.co.uk/g3sek<br>>
> _______________________________________________ Amps mailing list<br>>
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> http://lists.contesting.com/mailman/listinfo/amps<br><br>George T.
> Daughters,
> K6GT<br><br><br><br>_______________________________________________<br>
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Rich Measures, 805.386.3734, AG6K, www.somis.org
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