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Fw: [TowerTalk] Horizontal + Vertical Polarization Question

Subject: Fw: [TowerTalk] Horizontal + Vertical Polarization Question
Date: Sat, 22 Nov 2003 22:21:44 -0500
List-post: <>
Thanks for your interest and comments. Sometimes it improves the received 
signal on the other side... sometimes no difference. Most say the QSB fades are 
less severe, never eliminated of course. I would say that on average, that the 
QSB fading on either linear polarity if about 20-30 dB during liner 
polarization, is sometimes improved to 5-15 dB over the short term with 
circular. I have noticed that the Japanese flutter over the poles is much less 
fluttery in circular polarization, and the other operators have reported the 
same... most of the time (when ten was really open two years ago). 
Your points:
1. correct, not totally reciprocal, but transmitting circular helps to some 
degree most of the time.
2.The ionesphere will randomize the polarization over time, so the arriving 
signal is best initially generated circular or eliptical to reduce the worst 
case deepest fades over the short term. Long term fading that is caused by lost 
propagation path and absorption cannot be helped of course. 
3. True. A low gain omidirectional antenna would work almost as well... 
generally, but the arriving difference in angle of radiation may cause 
additional fading, or enhancement and is less defined as a system. Having the 
same gain and the circular wavefront seems to be a more defined system. 
Sometimes I see NO difference in circular polarization. Here is something you 
may find interesting: Somtimes circular is 3 dB stronger... indicating that the 
arriving signal has been faraday shifted to circular and is matching the 
"right-hand-sense" of my antenna!!! That was very unexpected and a real eye 
opener for me, although that condition is pretty rare. I have aslo noticed that 
sometimes the signal is MUCH worse in circular, indicating the arring signal 
has been made circular and is OPPOSITE sense and heavily attenuated. I watch 
what is going on and play the diversity "game", with some benifit as I attempt 
to match the current conditions.
About Your last comment:
More signal was not my goal actually. It was to reduce the severe selective 
fading on AM (amplitude modulation) since I spend most of my TEN meter activity 
on that mode (29.0-29.1). The distorted AM diring deep selective fades is 
anoying sometimes due to the wider bandwidth. My artical started out with this 
objective in mind.
In reality, it's fun to chat groundwave on TEN (SSB or AM) with most stations 
using the Antron-99 and other verticals for omidirectional QSOs. I live at the 
south shore of New york on Long Island, so the gain in either polarity is a 
benifit for evening groundwave nets. This was another  reason I started with 
the dual feedpoint loop, although I planned on the circular (AM/distortion) 
experiments. I am having a blast playing with it. To bad ten is slowly dying 
out. I may have to add another feedpoint to the 20 meter driven element and try 
it there.
George AB2KC

  ----- Original Message ----- 
  From: Jim Lux 
  To: GEORGE PRITCHARD ; Richard Karlquist ; ; 
  Sent: Saturday, November 22, 2003 8:07 PM
  Subject: Re: [TowerTalk] Horizontal + Vertical Polarization Question

  Interesting writeup, however, I'm not too sure about your statement:
  "In as much as a the receiving station benefits from diversity receiving 
antennas, the transmitting station reciprocally benefits in providing a more 
diverse signal to the receiving station. "

  For the following reasons:
  1) Ionospheric paths are not reciprocal (Faraday rotation being but one 
  2) On transmit, the goal is to get as much power radiated in the right 
direction as possible. Since losses in ground reflections are a significant 
effect, and highly polarization sensitive, one is probably best off 
transmitting in the polarization that minimizes losses, bearing in mind that 
the ionosphere will randomize the polarization on the way to the receiver.
  3) On receive, the goal is to get a signal which is above the received noise 
floor.  For this, CP or a diversity receiver are probably the best bet, since 
they minimize the maximum depth of a cross polarization null, and hence improve 
the probability that the received signal will be above the noise.  For what 
it's worth, if what you want to do is merely guarantee that the maximum null 
is, say, 10 dB, the diversity antenna can be a lot lower gain (i.e. it can be 
an omni) than the primary antenna, and in fact, probably should deliberately be 
lower gain (so you don't wind up building an "adding interferometer).  This is 
only true on HF, by the way, because a higher gain antenna gets more of the 
desired signal, but also gets more atmospheric noise.  VHF and higher, higher 
gain antennas are better, because the noise is in the receiver.

  (I maintain that the real value of a gain antenna, on receive, is that it 
allows you to remove interference, rather than increase the received signal 
power.  That interference might be atmospheric noise, which is not uniform 
(thunderstorms and the like are localized phenomena))

  ----- Original Message ----- 
  To: "Richard Karlquist" <>; <>; 
  Sent: Saturday, November 22, 2003 3:59 PM
  Subject: Re: [TowerTalk] Horizontal + Vertical Polarization Question

  > Gentlemen,
  > I am using circular polarization on TEN meters, using a 4 element quad.
  > Loops acting as parisitic elements "don't care" about polarity, with NO
  > polarization attenuation. That's another reason that quads rule. QSB caused
  > by polarity rotations are not isolated by the typical high "vertical to
  > horizontal isolation" that the parisitic elements on yagis have. In quads...
  > only the driven element attenuates the opposite polarity. For more info on
  > the topic of QSB fading with respect to: "Faraday rotations in the
  > ionesphere" , please go to the attached link, See my quad (and my son) and
  > click on "ARTICAL".
  > George AB2KC
  > ----- Original Message ----- 
  > From: "Richard Karlquist" <>
  > To: <>; <>
  > Sent: Thursday, November 20, 2003 10:27 PM
  > Subject: RE: [TowerTalk] Horizontal + Vertical Polarization Question
  > > > Has anyone experimented with feeding both a horizontally polarized and
  > > > vertically polarized antenna simultaneously on HF?  Such as,
  > > > feeding a horizontally
  > > > polarized yagi and a  vertical on 20, 15, or 10 meters?
  > >
  > > I haven't done that, but I have done a fair amount of A/B'ing
  > > of a 20 meter ground mounted vertical vs an inverted vee at 60
  > > feet.  More often than not, one is better than the other,
  > > but it's equally likely to be either one.  If you could
  > > feed both without destructive interference (and that
  > > assumption is by no means assured), then you would get
  > > a diversity effect and reduce QSB.
  > >
  > > I have also A/B'ed 2 verticals 800 feet apart and QSB
  > > on them is different (one may be up while the other is
  > > down, etc).
  > >
  > > Hope that helps.
  > >
  > > Rick N6RK
  > > _______________________________________________
  > >
  > > See:  for "Self Supporting Towers", "Wireless
  > Weather Stations", and lot's more.  Call Toll Free, 1-800-333-9041 with any
  > questions and ask for Sherman, W2FLA.
  > >
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  > >
  > >
  > >
  > _______________________________________________
  > See:  for "Self Supporting Towers", "Wireless 
Weather Stations", and lot's more.  Call Toll Free, 1-800-333-9041 with any 
questions and ask for Sherman, W2FLA.
  > _______________________________________________
  > TowerTalk mailing list

See:  for "Self Supporting Towers", "Wireless Weather 
Stations", and lot's more.  Call Toll Free, 1-800-333-9041 with any questions 
and ask for Sherman, W2FLA.

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