"Reg Edwards" wrote in message ...
Knowledge of antenna bandwidth is not of great practical use at HF
because
the Q of the feedline plus tuner has at least the same effect on the
overall
system bandwidth as the antenna.

I'm sorry, you lost me there Reg. How does the Q of a modern
broadband amplifier feeding a nom. 75 ohm feedline contribute more to
system Q than an 80 meter 1/2 wave dipole made from 2mm wire -- or for
that matter even one that's a half-meter diameter cage (though by then
it doesn't much matter for ham use)?

Cheers,
Tom
================================
Tom, who said anything about 75-ohm lines? And there's still a tuner, with
FIXED settings, to contend with.

I did, and in the scenario I proposed, there's a broadband amplifier,
but there IS no tuner (or if there is, it's set to a very low Q
anyway; the Q of an L network to match 75 to 50 ohms is far lower than
that of a single-wire antenna). There's no need for one if the
antenna is sufficiently broadband.

I thank you for the antenna-Q equation. But I disagree that "the Q of
the feedline plus tuner" always, or even very often, contributes more
to limiting the useful (single-setting) bandwidth of a nom. 75 ohm
half-wave dipole driven by a broadband amplifier than does the antenna
itself.

Cheers,
Tom