Ken,
you're placing too much emphasis on theory and perhaps not enough on
practice. Though that's your privilege and most of us are anxious to learn
more theory, but I think we should also be encouraging people to try new
stuff here and not just fall back on what we know works (i.e., your
grandfather's horizontal dipole).
When I talk about this antenna, I am not theorizing. I have used it in at
least 15 different QTH's, both portable and fixed. I use it all the time.
In a previous post, I have already described my experience with unbalance
and feedline radiation being minimum and effectively only noticeable when
running high power and using a less than perfect matchbox (i.e., T-filter
with external balun). The base of the antenna was 10 ft. off the ground.
The (DX) performance is OUTSTANDING compared to rotating the dipole
horizontal and placing it at a typical height (i.e., <30 ft.). And that's
the first of two reasons not to rotate the thing horizontal for the purpose
of getting better balance. The second reason of course is horizontal space
required to put it up. Most people have more vertical space than horizontal
space.
When I moved into my previous house in 1993, I put this vertical up for
about a year, until I got my tower up. Due to zoning laws, the tower was
just under 30 ft. The beam was an 8-el. Cushcraft Log Periodic. I also had
a 3 el. trap Cushcraft for expeditions. My subjective feeling was that each
performed about equally well (or poor). The limiting factor on performance
was height. Before you begin to speculate about my beam being bad, you
should know that in 1997 DL6RDR took 2nd place in Europe in CQWW CW contest
(QRP class) from my QTH - so the beam wasn't all that bad.
I kept the vertical up for a few months for comparison to the LP and there
wasn't a lot of signal difference, but F/B ratio of course is a big
advantage. So I took down the vertical.
When I moved into the present QTH 6 years ago, I put up the vertical again.
The tower laid on the roof of the garage for 4 years before I sold it, the
rotator, and the log periodic. I just use the vertical now. It simply
wasn't worth the extra effort to me to even put the beam back up at that low
height.
When starting from scratch, the vertical dipole gives you a big performance
boost over the horizontal dipole, and going to the expensive beam is only a
slight improvement unless you can raise it up very high (and then it is very
expensive and brings other problems).
Let me put it another way. I have probably personally influenced about 20
people to try this antenna. Most of them were in my contest club and most
used it for portable locations. No one ever came back to me and said it was
bad. A few even began praising the antenna openly on another reflector. One
even commercialized the antenna and now I'm going to buy his commercial
version.
This is not a miracle antenna or a wonder antenna, but neither is a
horizontal dipole or shortened (trap) ground plane. In my experience, the
vertical dipole outperforms the other two significantly. For portable work
(away from people and animals) I run it with the base just 1 ft. off the
ground and it works just fine.
All that glitters isn't gold. The downside to the vertical dipole is that
it is sometimes (e.g., thunder storms) more noisy than my horizontal dipole.
Under normal conditions it isn't, but sometimes it is. That's why I have
two antennas. With my Orion I can easily transmit on the vertical and
receive on the horizontal dipole.
73
Rick
-----Original Message-----
From: tentec-bounces@contesting.com [mailto:tentec-bounces@contesting.com]
On Behalf Of Ken Brown
Sent: Monday, July 11, 2005 9:54 PM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] vertical dipoles
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