> >You won't because a switched HV supply will cost more than the
> >entire PA, and is more difficult to engineer.
> >
>
> The engineering is not that hard. Two chips can take care of most of
> the work.
The single most difficult aspect of the design is the transformer.
A close second is RFI suppression, and switching devices at the
two or three kilowatt level.
> At the 500 watt level you can use the old (i.e. inexpensive)
> International Rectifier, or Motorola (now ON Semiconductor) IRF450 FET
> family or equivalents.
I don't think a 250 watt output PA using a few kilovolts with a
switching supply would be a good idea, but then people like the
DAF circuit and I think that is a bad idea also.
IMO, I'd just use a few FETS at the 250 watt level running off low
voltages and be done with it with less money, more reliability and
less weight.
> If you have some convenient chassis, to heat sink the FET's, then the
> whole rest of the supply will only weigh a couple pounds (1 Kg).
A few kilowatt few kilovolt supply that will handle a couple kilowatts
or more output only a few pounds? I want one!
> Diodes are no problem, either. 1N6517 (5000V, 1A, 150nS, in a package
> the size of a 1N5408!)
> And if you keep the cross sections small (B*dL), RFI is not that hard to
> control.
I don't think so.
The main problem is filtering the lines so the supply does not affect
the receiver. That's a real chore even with 200 watt 13.8v supplies,
let alone the supply described.
73, Tom W8JI
w8ji@contesting.com
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