Hello Stefan,
28 April 2017
They go bang when run as 2 amps in parallel with the W1VD combiner.
They then even blow the Varistors to kingdom come. I will try with the
combiner into my big water cooled dummy load, to see if the energy at
close down is from the loading coil / antenna. Without combining Jay's
original, cheap as chips FQA34N20L 200V LOGIC N-Channel MOSFETs work
fine. I have 1500pF and 10 ohms low inductance in series, drain to
gate, 1 per pair of FETs.
http://www.gatesgarth.com/FQA34N20L.PDF
Thanks Stefan, very few UK domestic properties have 3 phase,
unfortunately ;)
Best regards,
Chris 2E0ILY mailto:[email protected]
My part time LF grabber is at http://www.chriswilson.tv/grabber.html
> Hello Chris,
> These FETs are a good choice :-) You still manage to make them dead? And
> your supply voltage is 50V? That's not ideal. You can use 320 V directly
> from the mains, no heavy transformer needed, just a ferrite transformer
> on the RF side, to decouple the RF signal from the mains.
I was running >> 1.5 kW on 137 kHz (WSPR-15, no problem, not even in 100%
> TX mode) with just 4x IRFP460A, which are not as good as yours. So i
> don't really understand why you need a combiner at all. The 900V types
> would be fine for a 3-phase PA running at 560 V DC in a H bridge
> arrangement. A nice thought :-)
> 73, Stefan
--
Best regards,
Chris mailto:[email protected]
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