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ZL4AJS > QRP 23.06.05 15:40l 29 Lines 1115 Bytes #999 (0) @ WW
BID : B80168ZL4AJS
Read: GUEST DG9NBR
Subj: Re: Help with PA circuit
Path: DB0FHN<DB0MRW<DB0WUE<DK0WUE<DB0RES<ON0AR<ZL2BAU<ZL2WA<ZL4AA<ZL4GQ
Sent: 050622/2033Z @:ZL4GQ.#95.NZL.OC #:28815 [Invercargill] FBB7.00i
From: ZL4AJS@ZL4GQ.#95.NZL.OC
To : QRP@WW
GM0CSZ wrote:-
> For 5W output a cheap and common device is the MOSFET IRF510 ,popular
> within the QRP community with umpteen designs /examples available.
Thanks Frank but I've already found a way to get 5W out of a pair of
BD139s. Just stuck them in parallel (emitter to emitter, base to base,
collector to collector).
My next hurdle is the cores for the driver transformer and RFC. I'm using
some pretty poor F43 material toroids at the moment and they are only
rated up to 1 MHz. I am trying to work it at up to 14 MHz. Trouble is
cores are very rare in the shops for these frequencies, and I don't know
if I can use air or not. I does work at 3.5MHz though, but power drops off
very fast afterwards. If I got some decent cores, I imagine the power
would be a whole lot more even on 80m.
73.
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:: Andrew ZL4AJS@ZL4GQ.#95.NZL.OC ::
:: High School student (homeschooled) 17 ::
:: Ohai, Southland, NZ ::
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Timed 08:04 on 23-Jun-2005
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