On Jan 2, 2006, at 1:57 AM, Peter Chadwick wrote:
> What puzzles me about this size amp in ham use is where you get the AC
> power from for it.
According to a friend who used to be the Denver Office FCC Engineer in
Charge, the FCC confiscated a CB "big boy" that they could not power up
because their testing facility's (in Virginia) maximum capability was
480v-three phase and the big boy required 2160V-three-phase.
> If you ran it at full whack, you'd be needing to peak around 20kW from
> the mains, or around 100 amps from a single phase on 220volts. (let's
> not imagine running it from 115!) So you'd probably need 3 phase,
> which isn't standard domestically..... Running it 'conservative' still
> means a lot of filament power - 781 watts, according to my Eimac data.
> So for emergency comms, you'd need a damn big generator - or battery
> (sic), while for 'normal' use, you need to be pretty well heeled just
> to pay the electricity bill.
> Antenna requirements at this sort of power level are a problem, too,
> with flashovers, corona and all sorts of difficulties.
With 14k on 40m & 80m, a CF dipole made from solid #14 Cu with a 15cm
corona ring at each end did the job. It was fed with a RG213 and a
coax choke balun at its centre.
> Life may be too short for QRP, but the difficulties of this sort of
> level of QRO start getting a bit much for an amateur installation.
Indeed, Peter.
> 73
> Peter G3RZP
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>
Richard L. Measures, AG6K, 805.386.3734. www.somis.org
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