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[TowerTalk] Verticals, My Opinions

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Subject: [TowerTalk] Verticals, My Opinions
From: (James R. Duffey)
Date: Fri, 12 Jun 1998 08:42:40 -0600
When I was in High School, 1966 as WA0MWN, I put together a triangular
phased array of 3 14AVQs. Each antenna had 32 buried quarter wave radials
for 40 M. Now being older and wiser, I would do some things different, but
it was an effective antenna then and I had a lot of fun with it. I also won
some nice prizes in the science fair with it.

One of those 14AVQ antennas is still standing and is used regularly by my
Dad, WA0OML. It operates fine. One of the others had an internal trap
support break during a violent thunder storm and 12 years after we
installed it, My dad took it down and put up a Butternut. He gave the old
antenna to a local novice who reinforced the trap with a dowel and
reerected it. I think it is still in use. When the Butternut was erected I,
being older and wiser, added another 30 quarter wave radials for 20 M.

The second antenna was torn down by vandals during the infamous SDSU
student revelry in the 80s. It was replaced by a Cushcraft R-5 mounted
about 5 feet above ground.

Where is this all leading?

After helping my dad erect the R-5 I did a series of comparisons. (Yes I
know these are unscientific, I am a scientist) On 20 M I used the Northern
California beacon network at 14.1. The R was consistently the best antenna
on 20M, followed by the 14AVQ, and then followed by the Butternut. The
difference between the R-5 and the Butternut was never more than about 5 or
6 dB, and there were times when all three antennas were within 2 or 3 dB of
each other. During more subjective comparisons, including measurements on
W1AW on 40 M, the 14AVQ was a dB or so better than the Butternut on 40 M. I
recall measuring quite a bit of difference between the antennas on CHU, but
I don't recall which was better, or why.  The performance differences on 15
M and 10 M was similar to 20M, but I did not find a good signal source on
those bands to do some comparisons with.

The 14AVQ is certainly built better than either the R-5 or the Butternut. I
have tried to convince my dad that any of the three antennas would perform
better if erected on the roof, but his concern about lightning precludes

I think that verticals are good performers, but some attention needs to be
paid to details. Some suggestions;

1. Many of the maladies laid on verticals (noise and poor performance) are
the result of currents on the outside of the feed line. A good choke (air
wound or 1:1 "current balun") should be used at the feed point. The feed
line should be checked its entire length on all bands for currents on the
outside, and chokes added where current maximums are found.

2. A good ground is essential. The fine points on how this is accomplished
is open to debate, but for ground mounted verticals, published guidelines
are available. A good start is to determine how much wire you can afford to
buy (check out salvage dealers) and look in deVoldere or the Handbook for
"optimum configurations" to use that much wire. Add to the ground each

3. I don't want to open the elevated vs ground mounted debate, but a
vertical elevated an eight wave or higher above ground with 4 good resonant
radials ("a ground plane" antenna if you will) will be a very good
performer. Usually this criteria can be met on 20 M and higher by
installing it on the roof of even a single story home. If you do this
provide adequate lightning protection.

4. A high value choke or high value non inductive resistor, say 50 kOhm,
connected across the feed point will reduce some types of precipitation and
wind induced noise. The 14AVQ comes with such a choke. The resistor will
also let you check feed line integrity from inside the shack with a simple

A vertical can be a good performer. If you can't get a dipole up at least a
half wavelength the properly installed vertical is probably a better
alternate for low angle applications. - Duffey KK6MC/5

James R. Duffey               <>     (505) 764-3143
Maxwell Technologies Inc.
2501 Yale Blvd SE Suite 300
Albuquerque, NM 87106-4200

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