> 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. 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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