[AMPS] MLA2500 and screen voltage for 4CX800.

[conrad.farlow@virgin.net]

----- Original Message -----
From: "Douglas Snowden" <Douglas.R.Snowden@noaa.gov>
To: <amps@contesting.com>
Sent: Tuesday, April 10, 2001 1:31 PM
Subject: [AMPS] MLA2500 and screen voltage for 4CX800.


>
> I have decided to put a 4CX800 in the MLA2500
> sitting on the bench. I don't have a copy othe old QST (96?)
> article on doing this, but I remember seeing that they used some sort of
> regulator
> board to make screen voltage.  Wouldn't a string of
> zeners off of the plate voltage supply be just as good, and
> take up less space?  Anything wrong with this idea?
>
> Doug N4IJ
>
>
>
> --
> Doug Snowden
>        Systems Branch
> National Climatic Data Center
>   Asheville, North Carolina
>
> --
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Hi Douglas this is a very bad idea. The IMD performance of any tetrode is
dependant on good screen voltage regulation. The dynamic regulation of the
plate supply is pretty bad and this obviously causes problems with screen
regulation if a string of zeners are used. John Nelson GW4FRX wrote some
excellent articles on this in the 80s.John frequents this forum so he may
wish to comment.Meanwhile try this link for a solution
http://www.ifwtech.com/g3sek/boards/tetrode/tetrode-1.htm and some
background info.

Regards

Conrad Farlow G0RUZ


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