Gary's correct that radials make a tremendous difference in vertical antenna
performance. Typically, verticals have a lower take-off angle, which is
advantageous for HF DX work. However, some horizontal designs also exhibit
low take-off angles, esp with height. The horizontals have the advantage
over verticals of concentrating radiated power in the "desired" direction,
ie more gain, which also provides for better HF DX performance. Personally,
I have the most success, particularly at this low point in the sunspot
cycle, with horizontal designs...and the Super Loop and Carolina Windom
designs are among the best I've used. Unfortunately, I have had extreme
difficulty accurately modeling those, esp the Super Delta Loop, on anything
less than a very expensive modeling program (mostly because of the ladder
line trap/phaser in the middle of the top wire and how it interacts with the
rest of the antenna). I am currently building a second such loop with
relay-controlled feeds to make a switchable directional driven/reflector
element arrangement for even more gain.
Someone mentioned that your topographic situation is a heavy determining
factor, and I support that...if you have the trees or towers to get a
horizontal polarized antenna up high enough ("high enough" and wide enough
depends upon the band (in the case of an 80/40/40 Super Delta Loop the top
wire should be up at least 100ft and you should have at least 120ft length
available), then I'd go with that. If not, then you still have to figure
out how to get an unloaded vertical up high enough anyway (probably means
pouring concrete).
Stephen W9SK
-----Original Message-----
From: antennaware-bounces@contesting.com
[mailto:antennaware-bounces@contesting.com] On Behalf Of K9AY
Sent: Wednesday, September 23, 2009 7:33 AM
To: antennaware@contesting.com
Subject: Re: [Antennaware] Help! Which One
>....
> I also have a 65 foot vertical made from 3/4 inch copper water pipe at
>ground level. It has no radials, only a ground rod, and it
>well...sucks, I hardly ever use it unless I don't want to make a
>contact. I do think though that if I invested the time into putting a
>number of radials down, the vertical would begin to work better. I
>highly doubt though that it will ever outperform the zepp antennas.
>....
>
Paul (KG7HF)
________
Radials for verticals make all the difference in the world, just like height
does for horizontal antennas. Before writing off verticals, note one of my
experiences:
In 1985 after moving to Colorado, the first antenna installed was a 40M
rotatable dipole, but only at about 35-40 feet. It was dead ... like Paul's
vertical with no radials. Radiating straight up is no better than putting
power into lossy ground.
I re-arranged the antenna as a classic ground plane with a 1/4-wave vertical
section starting at 25 feet and three sloping radials. This was a fine
one-element antenna. Later, I added a second ground plane spaced about 165
deg. with five phasing settings. For DX, the array was only slightly behind
other local hams with 2 element beams at 70 feet.
I might note that the array was designed with the help of MININEC on an
early Compaq PC -- 4.77 MHz CPU clock, and one of the floppy disks upgraded
to a 5 MB hard drive!
73, Gary
K9AY
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