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Message-ID: <5.1.0.14.0.20020625172644.00b1e138@pb623250.kuleuven.be>
Date: Tue, 25 Jun 2002 17:41:14 +0200
To: rsgb_lf_group@blacksheep.org
From: "Rik Strobbe" <rik.strobbe@fys.kuleuven.ac.be>
Subject: LF: short vertical dipole
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Hello group,

Has anyone ever tried a short vertical dipole on LF (either built and 
tested one or simulated one) ?

The free space radiation resistance of a short vertical dipole would be 
only half of that of a vertical monopole of the same size (Ra = 
197*H^2/L^2, where H = dipole height and L = wavelength), so that would be 
a 3dB drawback. But close to (a perfect) ground the radiation resistance 
should increase (double) again, and win the 3dB back.
The main disadvantage would probably the relative low antenna capacitance, 
one would need a large loading coil (= large loss).
But on the other hand a dipole could be less dependent on 
ground/environement conditions (not as much as a loop but better than a 
vertical monopole).

I have been searching for articles on vertical dipoles on LF, but no 
result. So probably it isn't a good LF antenna, but I'd still like to know 
what it is worth.

73, Rik  ON7YD