----- Original Message -----
From: "Bill, W6WRT" <dezrat1242@yahoo.com>
To: <amps@contesting.com>
Sent: Sunday, March 14, 2010 8:46 AM
Subject: Re: [Amps] Clipperton-L parasitic suppressors
> ORIGINAL MESSAGE:
>
> On Sat, 13 Mar 2010 21:42:46 -0500, "Carl" <km1h@jeremy.mv.com> wrote:
>
>> The Q of the strap, wire, coil, has nothing to do with the design.
>>This is where the voodo starts.
>
> REPLY:
>
> This is the crux of the argument presented by the anit-Measures
> naysayers. Measures claims, and I agree, that a nichrome wire coil has
> lower Q than a copper one,
** No argument so far
and especially so when skin effect is taken
> into account. Skin effect increases with frequency and can be quite
> pronounced at VHF, one of Measures' primary considerations.
** So what? We are discussing a HF amp where its the goal to transfer the
maximum RF to the load and not heat up things unecessarily.
>
> How important that is is open to debate, but to just dismiss it as
> having "nothing to do with the design" is careless, IMO.
>
> Having said that, I must also say I don't completely agree with
> Measures' conclusions that copper wire coils are a real problem.
** Of course they are not a problem and they should be of the lowest
possible RF resistance at the highest operating frequency.
The
> great majority of Q-lowering is done by the resistor(s), and done
> properly, that is almost always enough.
** 99.9% in any well designed amp. I'll leave the remainder to hack jobs and
CBers.
If one wants to add more
> Q-lowering by using nichrome wire for the coil, be my guest. It can't
> hurt and it could help.
** If you want to live with the power loss be my guest. However a
conventional or my design which has almost no loss and costs a lot less than
the voodoo then I dont see the problem.
** IMO, the problem with old amps today is carbon resistors that have
increased so high in resistance that they are no longer effective. And hard
to find and expensive. The MOX resistor is the 21st century component of
choice.
>
> Electronic design is often as much art as science, and this area is
> clearly an example of that.
>
> 73, Bill W6WRT
** Art as in voodoo has no buisness in a science project. It would even get
you laughed out of a grade school project.
Carl
KM1H
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