[AMRadio] Home-brewing construction considerations


geoff ars.w5omr at gmail.com
Thu Jan 17 14:02:43 EST 2008


jeremy-ca wrote:
> Have you considered rebuilding for parallel operation and use a relay
> switched toroid input and a pi-net out? There are 6 band circuit
> boards available.
>
> It makes band changing a lot easier when the deck is shielded. Im
> converting a similar era deck that way. A further benefit is a coax
> fed antenna to further minimize stray RF radiation.
>
> There should be no problem getting to 15M with a standard air variable
> based upon the tube output C, the cap minimum and strays. I'll be
> using a vacuum variable and coverage will be 160-10M.
>
> With the tubes enclosed you will also need some fan assisted air
> exhausting.
>
> Have fun, 250TH decks seem to be everywhere lately.

Thanks for the suggestion and ideas, Karl... but I -rarely- get on 40m,
and I think once, in the last 10 years, even possessed a desire to even
want to 'try' 15m.  Besides, for anything above 20m, I can always run
the Viking II barefoot.  I've never been the 'gotta-have-high-power' type.

Besides, I've got extra plug in coils for the three bands this amp
covers.  The bottom is RF shielded and the three grid coils are
hand-wound, and 90 degrees out of phase with the output coil.

--
73



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