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[AMPS] Reverse-engineering design plate HV

To: <amps@contesting.com>
Subject: [AMPS] Reverse-engineering design plate HV
From: 2@vc.net (2)
Date: Thu, 15 Nov 2001 07:10:07 -0800
>
>In an old 5CX3000A 1.6-32MHz amp I am working on, the plate blocking caps 
>are rated at 8KV. Can I guesstimate from this what plate voltage was 
>intended? 

//   Eimac rates the 5cx5000A at 7kV in 24/7 AØ or FM.  8kV in SSB 
service should be ok.  The rated scrren potential is 1000v max.  To 
utilize the 5cx5000A's c. 6.5A-pk emissive ability, anode and screen 
potential should be maximal. The 8kVDC  blocker-C rating sounds adequate. 
 5kVDC vacuum caps are ok with up to c. 3000v-pk at 32MHZ.  This suggests 
that the TMC anode-PS was roughly 4000v.  For SSB use, I would consider 
removing the resonant filter -choke, converting to a C-filter, raising 
the screen potential.  P-out should then be about one standard 6db S-unit 
better than a SB-220.    To run it at c. 1500w, tune it up at full 
throttle - then back down the mic. gain until the anode-I barely wiggles. 
 Increase mic. gain as needed to maintain communications.  

>It was made by TMC, presumably to commercial or military specs.
>
>If it helps, it has vacuum variable caps in the tank rated at 5KV.
>
cheers, Jerry

-  R. L. Measures, 805.386.3734,AG6K, www.vcnet.com/measures.  
end


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