> 3. Yagi's need to be a half wave high to really play,
> but they may still hear OK at a lower height.
The crossover point between a dipole and vertical is actually
about 0.4 wavelength. A Yagi will have a slight advantage over
a dipole because of the slightly reduced (ca. 3 dB) radiation
up/down.
> 4. Verticals with a good ground system are as good
> as Yagi's for transmit depending on your ground conductivity.
> Fortuitously, I have very high ground conductivity, but
> of course YMMV.
Verticals suffer an automatic 6 dB penalty because of the lack
of ground gain. Yes, a vertical does very well in the ground-
wave region - better than any high dipole/yagi. However, once
the dipole/yagi is above 0.4/0.35 wave (100 feet/30 meters) the
horizontal antenna has better radiation at all take-off angles
in its "forward" direction than the vertical (vs. dipole) or
4 square/vertical beam (vs. yagi).
73,
... Joe, W4TV
On 7/16/2013 11:48 AM, Richard (Rick) Karlquist wrote:
The general consensus of the big guns on 75 meter
long path (mainly west coast to EU) was:
1. Yagi's hear better than verticals
2. On receive, having low sidelobes is more important
than forward gain or RDF or beam width, especially if
your noise is not uniform. For example, my quietest direction,
fortuitously, is 210 degrees, the direction of long path to Europe.
Rejection of noise from other directions makes all the
difference. A 4 square adjusted for a really clean
pattern may hear better than 7 elements with sidelobes.
Also, the 4 square should NOT be wide spaced.
3. Yagi's need to be a half wave high to really play,
but they may still hear OK at a lower height.
4. Verticals with a good ground system are as good
as Yagi's for transmit depending on your ground conductivity.
Fortuitously, I have very high ground conductivity, but
of course YMMV.
If you go with verticals, you generally need an alternate
receive antenna strategy.
Rick N6RK
On 7/16/2013 8:26 AM, Jorge Diez - CX6VM wrote:
I you have the supports for a 7 elements wire beam, I think will work as
support for 7 wire verticals, right?
Which is better, more gain? The 7 elements wire beam or 7 wire verticals
with the corresponding radials?
Thanks!
Jorge
CX6VM/CW5W
-----Mensaje original-----
De: TowerTalk [mailto:towertalk-bounces@contesting.com] En nombre de
Richard
(Rick) Karlquist
Enviado el: martes, 16 de julio de 2013 12:11
Para: floyd koontz
CC: towertalk@contesting.com
Asunto: Re: [TowerTalk] BIG WIRE BEAMS FOR 75 METERS
One of the regulars on 3.795 MHz around west coast sunrise a few years
back
had a wire beam with something like 7 elements beaming the long path to
Europe. He got great results with it.
Rick N6RK
On 7/16/2013 5:47 AM, floyd koontz wrote:
Sergio all of my info on this subject is on my website www.wa2wvl.com
In New Youk I had a 7 element on a 100 meter boom 100 feet in the air
toward JA. It worked great.
Floyd
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