I can only write about what I've used for years for DXing (160-80-40 top
loaded vertical over 24 sixty-six foot radials on the ground) or a TH-7 at
fifty feet and for close in work (a NVIS all-band doublet at 12 feet fed
with 450 Ohm window line.
The vertical which is approximately 32 feet tall is top-loaded umbrella
fashion using approx. twelve and a half feet of copper-weld style wire on
each of four guys using weed trimmer string for the remainder. The base is
inserted into the exposed section of a eight foot pipe sunk in the ground
with a DX-Engineering Radial plate connected to radials which run over the
septic leach field. The soil is approx. four feet of prairie-timber soil
over water-bearing clay on glacial moraine in a rural sub-division.
The NVIS antenna worked well for 40 meter contacts in Illinois and adjacent
states when the vertical would not. For several years I participated in ARMY
MARS and Illinois emergency communications nets and observed that stations
using dipoles and similar horizontal antennas at 40 feet or below usually
had much stronger signals than those using antennas with vertical
polarization (verticals, inverted L, etc.). I also learned that I could not
use the vertical and have effective communications with stations in Illinois
beyond ground wave.
The vertical as a transmitting antenna has been a very good DX antenna; I've
worked DX-peditions and every-day stations on every continent on 40 on down
with any power from 5 to 1000 Watts. One memorable QSO using the top-loaded
HV-2was breaking the pile-up of ZL9CI with 30 Watts on 40 meters at about
0855 UTC on 1-19-99. Another memorable QSO was AH1A on 80 CW using the same
HV-2, on 1-28-93 at 11:02 UTC (my Sun-rise). I've also used the vertical
for receiving low-band DX, but on occasion have used loops and Beverage
receive antennas.
Recently there's been much made of the polarization of received signals and
some have tried to claim transmitting polarization doesn't matter. It may
not IF you can get the dipole or array high enough, but most of us cannot.
Those who can't should use an efficient, effective transmitting vertical for
low band DXing. Some may use something on the ground or some may use
something elevated.
YMMV.... YCWWYCH
73 ES DX,
Gary -- AB9M
-----Original Message-----
From: Rick - DJ0IP / NJ0IP
Sent: Saturday, May 19, 2012 3:48 AM
To: 'Discussion of Ten-Tec Equipment'
Subject: Re: [TenTec] Radial Research
Technical research is useful but sometimes the discussion that follows
distorts the practical real world realities. Reading these threads
describing what it takes to obtain perfection, sometimes leads me to believe
that people with less knowledge will be scared off and not try anything.
That would be a shame.
REALITY: We all should strive to make our antennas as efficient as possible
and Rudi's work is an excellent guide, but even if you can't build anything
remotely close to what he describes, EVERYONE with just a little bit of
real-estate can build themselves a great vertical antenna with a lot less
effort than Rudi described.
I would remind you of the THREE reasons for using a vertical antenna in the
first place:
1. Because you have to; no space for a low band horizontal dipole
2. Because you want to improve your ability to work low band DX
3. NEW: Your sea container with all of your equipment and antennas got
lost in transit on its way to some distant island (see T32C DXpedition to
Christmas Island - www.tt2c.com ), so you organize a bunch of telescoping
fiberglass poles and some wire and build your vertical antennas on-site.
Let's focus on #2 because this would be the case where we have time and
space to apply what we've learned from Rudi.
It is fundamental to understand that a good working vertical on the low
bands is typically 2 to 3 S-Units stronger at a distance DX station than
your 40' high horizontal dipole. *** This is 12 to 18 dB improvement.***
Considering that, when someone says if I don't get it perfect, I will have 2
to 3 dB pattern distortion and 1 to 2 dB of additional loss. hey, let's get
real. If you live in a city, every antenna you put up has pattern
distortion, and your signal will never be as good as that of someone living
in the country with lots of space. That's no reason to just give up and not
do anything. Just do the best you can under your own set of circumstances:
>> Getting the most out of your own vertical with ground mounted radials is
pretty easy: just put down as many as you can under consideration of the
space, time and money you have available. Space them as evenly as you can,
but if you can't, you can't.
>> Getting the most out of your own vertical with elevated radials takes a
little bit more work but it's not that difficult. The radials must be
resonant. Measure and string as many as you plan to use, and then with a
grid dip meter or an antenna analyzer, measure each radial and tune them all
to resonance on the same frequency. This may be a different length for each
radial, considering the surrounding environment. If using the analyzer,
connect the coax shield to a ground stake. Getting them resonant on the
same frequency is easy, and will get some of that 2 to 3 dB back.
GRANTED, this is not the perfect solution, but it is the best most of us can
do and you will get a darn good performing vertical out of this; much better
than your low-hanging horizontal dipole.
73
Rick, DJ0IP
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