[TenTec] Radial Research - Dipoles & Verticals.

[Rick - DJ0IP / NJ0IP]

John, you bring up a good point; radiation pattern.

It has been said that a very low dipole begins to become omni-directional.
I have not modeled it.
But I can tell you, this has definitely not been my experience.

Many years ago (abt. 30), I had the problem that year after year I had great
difficulty to work UA9/UA0 Asiatic Russia, on 80m in CQWW DX Contest.  This
is a multiplier which "should be" easy to work.  I could hear them 5x6, 5x7,
I called and called an could never work them.  Maybe eventually I did get
them after a hundred calls (exaggerated), but it was a pain working them.
THE PROBLEM:  I always built my 80m dipoles broadside to stateside, because
I wanted to work the states.  And I did.  But I played hell trying to work
into Asia.

One year I got the idea that it was off the end of the dipole and that was
my problem; I connected the center and the shield of the coax together, and
then fed it to a matchbox.  I needed a counterpoise so I connected the
center and shield of the coax of my beam to the ground side and used it as a
counterpoise.  I called the UA9 and got him second or third call. It worked.
In fact it worked well.

I know this antenna was a much better dipole than it was a vertical, but
when feeding it as a dipole, I just couldn't get through to Asia.  It was
pointed in the wrong direction.  Once I fed it as a vertical,(a vertical
"T", to be exact) I worked the UA9 easily.  I repeated this trick for a
couple of years, then decided I needed to also have a vertical on 80m, in
addition to my dipole (NOT "instead of").

After that I began putting up an 80m vertical each year, just for CQWW
contest.
First I used a Butternut, later I switched to home-brewing my vertical
(cheaper and better).
Once I began using a half way decent vertical, the country count on 80m went
way up.

This is why I say that even if one is not able to put up a fantastic
vertical with 98 radials, ANYTHING halfway decent can be a big boost in
signal in one direction or another.

Sometimes "folklore" can improve your contest score (hi).

While operating 4U1VIC in CQWW DX contest at the United Nations Building in
Vienna, we were able to string our 40 and 80m dipoles 100m in the air.  That
is 333 ft. high!  (yes, the buildings are that high!)
We also placed verticals on the roof with lots of radials (20 or more, I
can't remember exactly).
The horizontal dipoles worked just as good for DX as the verticals because
the dipoles were high; very high.
At those heights, there was absolutely no advantage to having a vertical.

Back on the ground, things look different; very different.
The vertical is not a wonder antenna and it is not better than a dipole.
It just works better for DX when both antennas are low to the ground.

So if you can't get your dipole high in the air, a halfway decent vertical
can be a very advantageous weapon for you.
You don't need 98 radials, but it helps.
If you can string just 10 radials, the vertical will work well for you. 20
radials would be better.
Just don't expect too much with just 4 radials or less!

AND PLEASE DON'T INTERPRET THIS TO MEAN THAT THOSE MULTI-BAND TRICK
VERTICALS THAT WORK 9 BANDS ARE GOING TO WORK THIS GOOD; THEY DO NOT!
THERE'S NO FREE LUNCH.

I use home-brew monoband verticals, shortened by top-hat loading (wire
top-hats sloping 45 degrees to the ground).
Anyone who wants information on how to build these can find it on my web
site under ANTENNAS / Verticals.

73
Rick, DJ0IP

-----Original Message-----
From: tentec-bounces at contesting.com [mailto:tentec-bounces at contesting.com]
On Behalf Of John
Sent: Sunday, May 20, 2012 10:41 PM
To: Discussion of Ten-Tec Equipment
Subject: [TenTec] Radial Research - Dipoles & Verticals.

At the risk of again placing my foot on top of my tongue, I think it bears
mentioning that one of the hidden  issues in this discussion is what
radiation do you want or need.  The radiation pattern of a dipole 
at a  reasonable height resembles a donut on edge.   What this really 
means is that gain is a misnomer for the radiation off the ends of a dipole.
There is very little. With enough height there will be additional gain off
the sides of the dipole, compared to a vertical, with most of the gain
centered at 90 deg horizontal off the center of 
the dipole.   A  1/2 or 1/4 wl vertical's pattern is identical and 
rotated so that the donut is flat instead on edge and is centered  about 
halfway up the vertical.   Either a 1/2 wl vertical or a well grounded 
1/4 will have some gain but the pattern should be fairly distributed
vertically around  360 deg.

For those who enjoy being confused, I suggest downloading the free EZNEC
trial.  The trial also includes a number of antenna types as examples. 
As you learn to use the program, you will find the patterns you create to be
interesting but not exact unless you buy the complete program and start
learning how to insert elements such as traps, tuning coils, and feed lines.
As I understand it, and there are many who have a more complete
understanding of the program than I, this will allow you to get closer to
reality but the basic understanding will not change much.

73,
-- John / WA1JG
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