On Sun, 30 Jan 2005 12:56:05 -0600, Cecil Moore
wrote:

Buck wrote:
I am thinking that I might be able to improve my contacts by using a
vertical antenna since most mobiles use vertical antennas. I have
heard that once the signal bounces off the ionosphere, polarity isn't
as important as it is for local communications. However, when I was
assembling a 2 meter dipole antenna, I held it horizontal and turned
it vertical. I saw the s-meter go from nothing to s-7 and the
repeater go from silent to full quieting when I did this. I can't
help but wonder how much difference it will make with the mobiles.

2m signals don't bounce off the ionosphere. It is not clear what
band you are talking about. For sky wave communications on HF, the
polarization doesn't much matter. For ground wave communications,
polarization matters.

A couple of years ago I was keeping a sked with a friend on 10 meters.
The path was about 1800 miles. I mounted a vertical element on the end
of the 3 element beams boom. I wanted to try circular polarization. By
using proper feed line lengths and switches I could switch between
right or left hand circular polarization. The beam had a little more
gain than the single vertical element but the effects were dramatic at
times.

Sometimes right hand was best sometimes left hand was best.

But what turned out to be interesting was when both vertical and
horizontal where in phase and connected together. It lowered overall
signal strength a little but the fading was much less.

At times signals would fade deeply on either vertical or horizontal
polarization. Circular helped a lot but the signal kept changing
between left hand and right hand so you had to keep flipping the
switch.

With both antennas in phase it would receive vertical or horizontal
without changing anything. Very smooth constant signal.

At other times just the beam was better alone.

Transmit appeared to benefit the same. He could hear me with less
fading with the in phase antennas as well. My friend on the other end
only had horizontal polarization. He was going to try a vertical
element too but never got to do it before 10 meters died.

73
Gary k4FMX