Phil...My 4-1000Ax2 (7200 plate voltage) responded very well to parasitic
supressors as you describe as well as three turns over a 100 ohm supressor
at the cathode as well.
Amp`s been real happy since....And I didn`t use nichrome either...Jim.
----- Original Message -----
From: Phil Clements <philk5pc@tyler.net>
To: 2 <2@vc.net>; AMPS <amps@contesting.com>
Sent: Monday, March 24, 2003 8:19 AM
Subject: Re: [Amps] Hard-drive Dive
> ** The tradeoff with Carborundum/Globar ? units is that they have a bit
> much intrinsic L for optimal VHF suppression service. To explain: To
> exhibit good suppression, the inductances of the R and the L paths need
> to widely different.
>
> After experiencing problems with 10 meter operation on a 4-1000A amp
> years ago (R-sup toasting) I ordered a suppressor direct from Eimac that
> they used on all their Eimac-Varian RF generators. (2X4-1000A) It is made
> up of a 120 ohm 25 watt Globar resistor surrounded by two turns of silver
> plated quarter-inch copper tubing, 1 inch in diameter. After 25 years, I
can
> still read the printing on the Globar. The trade-off seemed to pay off.
Eimac's
> stock suppressor for their 3-1000Z is a 10 ohm 25 watt Globar, with two
turns
> of half-inch silver plated copper strap, tightly wound around the
resistor, and
> secured with clips. This allows quick checking of the R-sup value during
> annual spring cleaning by just removing one clip.
>
> I have used all of Rich's products at one time or another, and have had
> excellent results with 3-500Z and smaller tubes.
>
> There is a world of proven engineering and research out there which allows
> us laymen to pick and choose the right components for the job at hand.
> My fear is that with the passing of so many Handbook authors and the
> "dumbing down" of the ARRL Handbook to a QRP manual, no one is
> there to pick up the ball to document this legacy of knowledge for future
> builders.
>
> (((73)))
> Phil, K5PC
>
>
>
>
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