The tuning procedure described in "The VHF/UHF DX BOOK" Chapter 6 is excellent.
That will bring you to a point where the G2 current is very low. (and you have
max output)
Using that approach will also give you very good reports.
OZ5TG
----- Original Message -----
From: "Richard" <2@mail.vcnet.com>
To: "Harold E. Johnson" <w4zcb@mchsi.com>; " AMPS" <amps@contesting.com>
Sent: Monday, July 01, 2002 9:25 PM
Subject: Re: [Amps] 4CX250 IMD
> Compared to poor regulation, yes. Compared to a well-engineered zener
> shunt screen regulator, probably not a significant improvement. To
> arrive at good linearity with a 4cx250B/R/BC/7203, load for less screen
> current, use maximal anode supply V. and add c. 5-ohms of RF-NFB R in the
> cathode (Rk). See Fig 10 on my Web site.
>
> >G3SEK is vacationing in the states at the moment, but he gets significant
> >improvement in IMD suppression with the tube by holding the screens within
> >millivolts using active regulation.
> >
> >W4ZCB
> >
> >
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> >_______________________________________________
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> >
>
>
> - R. L. Measures, a.k.a. Rich..., 805.386.3734,AG6K,
> www.vcnet.com/measures.
> end
>
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