Message-ID: <000b01c0c3b9$ffabf740$58b21bca@xtr743187>
From: "Vernall" <vernall@xtra.co.nz>
To: rsgb_lf_group@blacksheep.org
References: <002001c0c3ab$e4b58860$1b3f073e@default>
Subject: LF: Re: diplexer ....more
Date: Fri, 13 Apr 2001 13:34:39 +1200
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Alan,

I comment on one part of your reply:

> To Bob, I think
> the efficiency of the PA is only high if you calculate the input power to
> the
> 'total' output power (wideband), the harmonic power doesnt 'improve your
QSO
> getting potential' surely as its in the BC band in Europe!! Isn't it the
> case that the harmonic power is not reflected back to the the PA , where
it
> could cause trouble but the input to the diplexer can still be a square
> wave, giving high efficiency in terms of the heat generated on the
heatsink.

The "squarewave" action in the PA devices is basically why the very high
overall efficiency is possible.  The squarewaves could be thought of as
having harmonics (a la Fourier series) but they could more simply be
regarded as inclusive of "hard switching" where there is minimal coincidence
of voltage and current (the product being dissipation).  The squarewaves are
"beneficial" and could be considered as reducing the heating compared to
them not being present.

73, Bob