>> From: km1h@juno.com (km1h @ juno.com)
>> Subject: Re: [AMPS] impedance of nichrome lower
To: <amps@contesting.com>
>> Date: Fri, 12 Sep 97 15:46:04 +0000
...snip...
>I think the point everyone misses is if the suppressor coil is LOADED
>with a parallel resistance, it doesn't matter what material you use.
True enough, Mr. Rauch IF the 29MHz dissipation in Rs is Not a
consideration -- which is the point you would apparently like for
everyone to miss, but which seems a bit unlikely.
>The Q and impedance of the suppressor is mainly established by
>the inductance in the coil and the value of the parallel resistance,
>NOT by the small series resistance in the wire itself.
Which does not explain why Mr. Rauch cancelled his post proposing that 5
ohms of ESR be added to Ls, and the results calculated by Us. It seems
that Mr. Rauch calculated, cancelled, and stonewalled the issue ever
since. - - Thanks, Will.
>
>Picture this circuit. We have a long anode lead that goes from the
>tube to the tuning cap, and through the cap to the chassis and back
>to the tube. That path almost always looks very inductive at VHF, and
>the stray C of the tube "tunes" it like a parallel circuit.
>
>The suppressor is in series with that lead, not in parallel with it.
>
>Ask yourself this question. What value of resistance in SERIES
>with that inductance would lower the Q the most?
>
>Of course the answer is the highest resistance we can get!
>
>What we want the coil of the suppressor to do is look like an open
>circuit at VHF, so ALL of the RF path is through the resistance that
>dampens the anode system. That's why the AL80 suppressor coil has
>such a very high impedance at 200 MHz (that's about where the AL80A
>and B oscillate at, if the suppressor is jumpered).
Apparently, the frequency of oscillation drifts about. During the
suppressor debate Mr. Rauch stated that it was 155MHz.
...snip...
>All things considered, the nichrome is not much different than the
>stock suppressor at upper VHF.
>
About 40% different according to Wes' measurements - and with a bit less
29MHz dissipation in Rs, no less.
>> If you really want to push your luck we can try SB-200 and
>>FL-2100's !
>
>They oscillate at HF, not VHF. They really need neutralized,
ROFL. Not according to my dipmeter. And you won't find mention of the
Rauchian neutralizing method in Eimac literature.
On and on. It's a long trip from Lake Victoria to Alexandria, folks..
Rich---
R. L. Measures, 805-386-3734, AG6K
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