TT:
I have seen similar performace differences on Topband between my
shunt-fed tower with seven radials and my erstwhile 160M inverted L with a
half-mile of radials (!) and the vertical element 45 feet long. My tower
hears and talks about 5-10 dB better than the L ever did. (Although an L is
certainly a cheaper alternative than putting up a tower, Hi Hi.)
FWIW.
73 de
Gene Smar AD3F
----- Original Message -----
From: "Richard Karlquist" <richard@karlquist.com>
To: <towertalk@contesting.com>
Sent: Sunday, November 23, 2003 11:45 AM
Subject: RE: [TowerTalk] Horizontal + Vertical Polarization Question
> This experimental data may be of interest:
>
> Friday night I did a bunch of A/B tests between
> an 80 meter inverted vee, 120 degrees apex
> angle, 60 feet apex height versus a voltage
> fed vertical. The vertical is actually my
> top loaded 90 ft 160 meter vertical, which
> is resonant at 1.830 as a voltage fed antenna,
> and resonant at the second overtone as a
> current fed antenna. It is over a big ground
> screen. The two antennas are separated by
> 800 ft, so there is no interaction. The vertical
> has an insulated base and is fed through a series
> 180 pf capacitor with a shunt inductor around 10
> uH from the vertical to ground.
>
> The results were immediately obvious. Almost
> all stations were 5 to 10 dB stronger (on a
> calibrated S meter) on the vertical. Only
> very local stations were stronger on the
> inverted vee, and in that case up to 20 dB
> stronger. A true cloud warmer. The crossover
> point seemed to be about 300 miles. Several
> station in Las Vegas were equal strength on
> both antennas (including an Art Bell sighting :-)
> I made a dozen or so QSO's and everyone commented
> on how well the vertical was getting out.
>
> Thus in this case, it probably doesn't make any
> sense to combine the antennas, except in Sweepstakes
> where I wouldn't want to miss the many SF Bay area
> stations that are 50 to 100 miles away.
>
> I am fairly sure the low height is the problem for
> the vee. A rotatable dipole at 90 to 120 feet would
> probably start to compete with the vertical. It I
> had that kind of antenna available, then I could
> revisit the polarization question.
>
> Rick N6RK
>
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
questions and ask for Sherman, W2FLA.
>
> _______________________________________________
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> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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