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
http://www.ifwtech.co.uk/g3sek
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