>rlm wrote:
>>>We could program a server to just dump
>>>the archives to the list every six months and you could not tell the
>>>difference.
>>
>>** Not quite. In December, 1996, just before Wes, N7WS, measured
>>various parasitic suppressors on the bench with a HP Model 4191A RF
>>Impedance Analyzer, the method was hailed as a benchmark by both sides
>>of the issue.
>
>So it was. We all believed that Wes's measurements on the suppressors
>would answer all the questions.
>
>But during the debate that followed, we found out that it isn't as
>simple as we'd believed.
>
>There is no way to evaluate the performance of a suppressor without also
>knowing a few things about the amp in which it will be installed: the L
>and C of the VHF parasitic resonant circuit (or more practically, C and
>the resonant frequency).
>
>Without that extra information about the amp, you cannot work out the
>damping resistance
** Rp is more like an equivalent Shunt VHF load at the anode resonant
freq.
>that the suppressor will place across the tube, at
>the parasitic frequency. In other words, you cannot determine the
>effectiveness of a suppressor by making measurements on the suppressor
>alone.
>
** Quite true, Ian. However, since 2, 3-500Z HF amps typically have
anode resonances of 95MHz to 120MHz, Wes' measurements at 100MHz were not
meaningless.
>
>> Now that Eric has proposed an encore measurement, Mr. Rauch says it's
>>really and truly a bad idea because we need to be looking at "the
>>system". However, a Z-analyzer rather obviously can't be used to
>>evaluate a system since it evaluates individual lumps of R-C-L, so the
>>system arguement appears to be another ploy.
>>
>The need to know about the "system" - the suppressor *and* the amp in
>which it will be used - is not a ploy. It's that thing we learned, the
>last time we tried this game.
** The amplifier system includes the power supplies. What do they have
to do with VHF?
>
>"Those who cannot remember the past are condemned to repeat it."
>-George Santayana, 1863-1953, American philosopher
>
** "Unlearned in history, they allow themselves to be governed by the
Unknown Past." -- Historian John Acton (1834-1902)
- R. L. Measures, a.k.a. Rich..., 805.386.3734, AG6K,
www.vcnet.com/measures.
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