>> From: Peter Chadwick <Peter.Chadwick@gpsemi.com>
To: <amps@contesting.com>
>> Date: Mon, 8 Sep 97 14:18:09 +0000
>
>Measures wrote:
>> >- The advantage of resistance-wire suppressors is that, at 100MHz,
>> >they exhibit about 40% less Rp than do otherwise similar, conventional
>> >suppressors made from copper-wire.
>
>You replied:
>> Is this 40% less Rp than the 'conventional' parasitic suppressor i.e.
>> coil and shunt resistor, or just 40% less Rp than the coil alone?...
...snip...
>If you look at N7WS's data, and his conclusions, the stock AL-80B
>suppressor is essentially equal to the nichrome model near
>the frequency where stability is a problem, although the stock
>suppressor does lower SYSTEM Q at VHF slightly more than the
>nichrome replacement.
Good advice, Mr. Rauch. I looked. How could Wes have been measuring
'SYSTEM Q'? The suppressors he measured were not installed in an
amplifier? At the frequency nearest to the AL-80's 155MHz anode
resonance, 150MHz, Wes measured the copper-wire suppressor's Rp at 166
ohms, and the resistance-wire suppressor's Rp at 103 ohms.
>The "advantage" of the nichrome really kicks in at HF, as evidenced
>by the heat produced and efficiency lost on upper HF when the
>nichrome suppressor is added.
Evidence is norally measured. Does it seem plausible that the resistance
of Ni-Cr alloys 'kick in' and starts increasing below 30MHz? Does it
seem likely that the resistance starts decreasing above 30MHz?
(Twilight Zone Theme)
>2.) A direct short has an Rp of zero ohms.
>
It seems that Mr. Rauch admittedly missed the boat on admittance (Y). A
direct short sends Rp up through the roof.
Rich--- .
R. L. Measures, 805-386-3734, AG6K
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