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Re: [Amps] Source for plate xfrmer

Subject: Re: [Amps] Source for plate xfrmer
From: Ian White GM3SEK <>
Reply-to: Ian White GM3SEK <>
Date: Tue, 14 Feb 2012 07:49:36 +0000
List-post: <">>
Steve Bookout wrote:
>This is where I think i got into trouble.  ??I rebuilt a BTI 2000 that 
>had already had another PS put in place of the original. The resultant 
>load impedance was so far from the original design that efficiency was 
>REALLY low.  ?I built a new supply with a transformer I had used in 
>another amp.?I used GM3SEK's on-line calculator to rebuild the RF deck 
>into a fixed, 80 meter only amp.  (This was for the 80 m position at my 
>M/M.) ?Really beefed things up and was well satisfied with how the RF 
>deck worked out.?PS, not so much.  Abt 4500 volts no load and abt 3600 
>at 500 mils.  ?Now, the real working voltage is much less than I 
>designed the RF deck for.  Efficiency is off, although not nearly as 
>bad as when i started.?A year and a half ago, I put it on the air for 
>CQWW CW.  1300 watts during a tune up, equals abt 1600, or more when 
>sending CW. Dynamic regulation stinks!  You have to tune, then send CW 
>to see where the power is.  Adjust and repeat.?I remember saying to 
>myself 'Blow up you &%¥€#?@, then I'll get you right!'.  It stayed 
>on 3502.3 KHz all weekend, for abt 1200 80 mtr Q's.  ?If that had been 
>because of resistance in the caps, they would have quickly died from 
>the heat. BTW, they are low ESR, 105 C caps.?Anyway, it is rugged, 
>although it is far from perfect.  I'm a bit like the TV character 
>'Monk', and this is just bothering the Hell out of me.?Both my 160 m, 
>4-1000 amp and my 40 m, 8877 amp have power supplies that use Dahl 
>transformers at 4200 v rated at 1.5 A CCS. They hardly flicker.??I know 
>I checked the secondary resistance.  I knew better, but it just didn't 
>sink in, I guess.  Don't remember what it was now.??Anyway, this is 
>where I am and how I got here.??
I'm glad the Pi-net calculator worked for you.

As for the &%¥€#?@ transformer, have tried checking it out with 
M0KGK's 'PSU Designer' software? Follow the link (below) and you can 
also download some HV-related example files from my web pages.


73 from Ian GM3SEK
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