On Thu, 11 Sep 1997 13:28:56 +0000 w8jitom@postoffice.worldnet.att.net
writes:
>> From: "Ian White, G3SEK" <G3SEK@ifwtech.demon.co.uk>
>> Subject: Re: [AMPS] impedance of nichrome lower
To: <amps@contesting.com>
>> Date: Thu, 11 Sep 97 07:46:57 +0000
>
>Hi Ian,
>
>I thought about just ignoring Rich's comments, because this stuff
>just goes on endlessly.
The rest SNIPPED
It could stop if there was agreement Tom. The way I view it is that there
are a number of individuals on this reflector with engineering
backrounds. I have yet to see a unaminous consensus on the suppressor
issue. To me that means a lot more discussion is warranted, no matter how
painful to some.
I have no personal interest in who wins; I just want to know the answers.
Remember, they used to execute those who professed the world was not
flat.
73...Carl KM1H
But in fairness I guess I should correct one
>thing he said.
>
>> Rich Measures wrote:
>> >During the grate suppressor debate, I repeated asked Mr. Rauch to
>design
>> >a copper-wire parasitic suppressor that equaled the performance of
>the
>> >resistance-wire suppressor. I repeatedly asked Ian White and Wes
>to
>> >design one. ......... So far, nothing.
>
>Ian said:
>> Not true, as DejaNews would show, but I'll bite again.
>
>Not true as Dejanews says, and not as I recall either. The same is
>also so with Rich's references to my making comments about
>Rich's nurse. As a matter of fact, just two days ago right here Rich
>blamed that one on N7WS. Today he blames it on me.
>
>The truth about that, as I recall, was that Rich asked Wes to NOT
>post the test results because it would mean laying off his nurse,
>who helps ship the kits Rich sells. Rich said his nurse needed the
>money. To which Wes replied he didn't care if Rich's nurse got
>to lick stamps or whatever he does for a living. Why I'm any part of
>that conversation, or what on earth such a simple comment means, and
>what it has to do with the topic at hand.... is beyond me. I
>certainly had nothing to do with that verbal exchange.
>
>> The second question is: what is the difference between the two types
>of
>> suppressor at other frequencies?
>> Plotting the N7WS measurements on a (log Q) versus frequency scale
>> showed that the Q values of the two different types of suppressor
>track
>> quite closely across the VHF range. The measured Q values were about
>40%
>> different at 100MHz, but the two curves run pretty much parallel
>across
>> the VHF range. On a log scale, that means that they pretty much
>> maintained a 40% ratio between them.
>>
>> So, if you make a conventional R/L suppressor that mimics the Rp-Lp
>> behaviour of the R/NiCr suppressor EXACTLY at one chosen VHF
>frequency,
>> you'd then find that the two curves remain very, very close across
>the
>> VHF band.
>>
>> But N7WS's measurements show that the Q of the conventional
>suppressor
>> rises FASTER at HF - in other words, at HF it looks less like a
>resistor
>> and more like a small inductor, which is exactly what it's supposed
>to
>> do. The Q of the R/NiCr suppressor also rises at lower frequencies,
>but
>> more slowly. In other words, the significant difference between the
>two
>> types of suppressor is not at VHF, where their performance can be
>made
>> almost identical. The main difference is at HF.
>>
>> OK, that's it for a second time, in a different newsgroup and
>hopefully
>> explained even more clearly.
>
>The best use would be in a system with HF or near HF instability,
>although a low-Q tank would do the same thing.
>
>73, Tom W8JI
>
>--
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>
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