[Elecraft] OT: Vertical antenna ground systems

[Alan Bloom]

N6LF has done some wonderful experimental work on vertical antennas.

He found that a radial laid on the ground experiences a velocity factor
similar to coax cable.  A quarter wavelength is only about 60% of its
free space value.  If you make the radials a physical quarter wavelength
long, they are actually closer to a half-wave electrical length
(anti-resonant).

With 4 radials he actually got about a 3 dB improvement by making them
SHORTER!

For my next vertical I will definitely plan to tune the radials.  I
think I'll try laying out a 1/2-wave dipole on the ground and then trim
it to resonance.  Then cut all the radials to equal the length of one
half of the dipole.

Al N1AL


On Tue, 2008-11-04 at 19:10, Ken Kopp wrote:
> Of potential interest to those who use verticals with their Elecraft 
> rigs.
> 
>          http://www.antennasbyn6lf.com/
> 
> 
> 73!  Ken Kopp - K0PP
>       ElecraftCovers at rfwave.net 
> 
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