>
>
>> >this. In all but one case, I am talking about Thoriated Tungsten
>> >tubes rated from 500 W to 250 kW dissipation, but they are also used in
>> >linear class AB 1 or 2 service. BUT I am not dealing with communications,
>> >where 2 tone IMD and such is a problem.
>>
>> Presumably, if there's enough emission for a given carrier level, there's
>> enough for the same pep.
>
>The problem everyone seems to miss, and it certainly is a problem,
> is that amateurs have varying drive power from band to band.
>
>Amateur operators tune the amplifier differently from time-to-time
>and certainly from band-to-band, and the amplifier itself varies in
>characteristics from band-to-band.
>
>It is poor thinking to attempt to copy commercial single band
>applications that use ONE mode, in amateur service. That's
>especially true is the person making the adjustments doesn't set
>emission under worse case conditions.
>
>For example, you could not possibly set the SSB filament
>emission correctly by looking at a CW signal...because the HV
>and often the exciter power are higher on SSB peaks than they are
>on CW peaks. That means more peak emission current for SSB.
>...
/\ A cathode's peak emission current ability is not a function of anode
supply V. RL = e/i is a function of supply V.
>On some bands (typically ten meters) peak emission for a given
>output is higher, so now we have added a new dimension of
>concern.
>
>All of this will almost certainly be poorly handled, no one will watch
>IMD or be sure they are setting emission under maximum demand
>conditions, just to cure what amounts to a "non-problem" because
>we want to copy what single-frequency single-emission 24 hour
>operation people do.
>
>I'd wager more than 50% of the people wouldn't even set or
>measure filament voltage correctly, let alone do a proper emission
>evaluation.
>
>Certainly we don't want to run filaments at more than
>recommended voltage, and it would be helpful to tell people how to
>properly measure filament inrush and voltage, but anything beyond
>that is foolish.
>
>
>
>
>
>73, Tom W8JI
>W8JI@contesting.com
>
>--
>FAQ on WWW: http://www.contesting.com/FAQ/amps
>Submissions: amps@contesting.com
>Administrative requests: amps-REQUEST@contesting.com
>Problems: owner-amps@contesting.com
>
>
- R. L. Measures, 805.386.3734, www.vcnet.com/measures.
end
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