Message-ID: <4B995D52.6000802@abelian.org>
Date: Thu, 11 Mar 2010 21:14:58 +0000
From: Paul Nicholson <vlf0308@abelian.org>
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Subject: Re: LF: Re: DREAM 9 ANTENNA
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Jim Moritz wrote:
 > However it would fail at 9kHz, or on any other band, if the
 > total loss resistance of the antenna and main loading coil
 > is >50ohms.

True enough, the impedance into the coil would typically be much
higher than 50 ohms.

But Mal Hamilton wrote:
 > ...and if necessary add another small inductor in series to
 > ground and adjust with taps up from ground to get a 1 : 1 match
 > with the coax feed from the TX,

Tapping into the coil in the manner described, or more likely,
using a tapped cored transformer, would bring the impedance into
the range of amplifier outputs.

Forget 50 ohms, coax lengths are such a short part of a wavelength
that there is no longer any need to convert to and from 50 ohms,
it has no relevance here.   Match the amp directly to the transformer
at its own output impedance, perhaps an ohm or less.
-- 
Paul Nicholson
--