Yes, on some of the bands circular polarization is used for EME
On Wed, Feb 12, 2014 at 12:47 PM, Charlie Cunningham <
charlie-cunningham@nc.rr.com> wrote:
> BTW - does anyone know if the EME boys employ circular polarization?
>
> 73,
> Charlie, K4OTV
>
> -----Original Message-----
> From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of
> Charlie Cunningham
> Sent: Wednesday, February 12, 2014 1:35 PM
> To: 'Tom W8JI'; dado@prijedor.com; topband@contesting.com
> Subject: Re: Topband: circular polarization on 160m
>
> Hello all,
>
> My original post regarding circular polarization receiving antennas for
> 160 was posted 2/2/2014 as a comment on Bill, VE3CSK's post regarding his
> observation of apparent rapid polarization shifts in the signal received
> from FT5ZM, on Amsteram Island at their sunrise. Bill was using his K3 in
> diversity mode to observe the apparent rapid polarization shifts by using
> both vertical and horizontal receive antennas. The rapid apparent
> polarization shifts seemed quite different from the slower QSB that we
> often experience on 160. I post my original hurried off-hand comment and
> Bill's post below;
>
> "I wonder what circular-polarized RX antennas might have to offer on 160?
>
> Charlie, K4OTV
>
> -----Original Message-----
> From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of Bill
> and Liz
> Sent: Sunday, February 02, 2014 8:37 PM
> To: topband@contesting.com
> Subject: Topband: FT5ZM SIGNAL
>
> I have been listening several evenings now on 160M using my K3 in
> diversity mode with the TX vertical array on one receiver and a full-wave
> horizontal loop on the other. I have been struck by the often rapid change
> in the signal as received on one antenna or the other. As sunrise on
> Amsterdam approaches this shift becomes quite rapid, with the recovered
> signal bouncing back and forth ear to ear. Early on, before I began
> listening in diversity mode, I thought it was rapid QSB taking the signal
> down into the noise but now realize that it is the angle of the arriving
> signal which is rapidly changing over the path.
>
> No wonder some of the guys have been having problems copying/working the
> expedition on topband!
>
> Bill VE3CSK"
>
> This seemed to provoke an interesting, lively and informative discussion
> by a number of people who have explored 160m ionosphere propagation in far
> greater depth than I have. Some of the commentary piqued my interest and
> caused me to want to do some more research! Thanks guys, and thanks, Tom,
> for your recent postings of your recordings from KH6AT etc.! Rather
> informative and thought-provoking!
>
> I must confess that all of my experience with circular polarization has
> been at UHF (400 MHz range) for spacecraft telemetry and 1.4 GHz for GPS
> signals. In these cases circular polarization is employed to contend with
> the Faraday Rotation of signals as they propagate through Earth's
> atmosphere. These signals generally originate beyond the ionosphere except
> for a few birds that might pass through the "magneto-tail" on the lee-side
> (dark-side) of earth away from the solar wind. Very different from 160m
> signals that originate on Earth's surface and are reflected from an
> ionization layer in the ionosphere!
>
> Bill's observations are really interesting and seem to suggest something
> other than the usual slow fades that we are used to on topband. Surely
> piqued my curiosity!
>
> I would think that with proper phase control one could construct circular
> polarized 160m receive antennas that could be less than full-size if
> preamps were employed. It's interesting to consider that such an antenna
> would probably be RHCP in one direction and LHCP in the opposite direction!
> If I wasn't so disabled at present, I' be tempted to build something to
> experiment with, just because I miss building experimenting with and
> measuring antennas! Very enjoyable
> activities for me!
>
> Anyway, thanks all for all the commentary and insightful and
> thought-provoking discussions! Bill's observations seem to suggest
> something different at work that may deserve some further investigation and
> exploration! That led me to wondering about circular polarization, or
> perhaps some rapid high-speed commutation between horizontally polarized
> and vertically polarized receive antennas. Thanks!
>
> 73,
> Charlie, K4OTV
>
>
>
> -----Original Message-----
> From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of Tom
> W8JI
> Sent: Wednesday, February 12, 2014 10:41 AM
> To: dado@prijedor.com; topband@contesting.com
> Subject: Re: Topband: circular polarization on 160m
>
> Here are some pictures and a sound file or two...
>
> http://www.w8ji.com/HF%20circular%20polarization.htm
>
> ----- Original Message -----
> From: <dado@prijedor.com>
> To: <topband@contesting.com>
> Sent: Wednesday, February 12, 2014 6:41 AM
> Subject: Re: Topband: circular polarization on 160m
>
>
> >
> >
> > hi Guys,
> >
> > interesting discussion
> >
> > If want, hear this file,
> >
> https://drive.google.com/file/d/0B8I6Nck0GwTdYTI0MzVkY2QtYjUyYS00YmE3LTk4NTktNWVlNzE2ZGFiYmE1/edit?usp=sharing
> >
> >
> > this is E74AW and OZ1LXJ recording of ZL3IX, at same time, John was
> > so kind and sinchronise those two audio recordings together in one file,
> >
> >
> > will hear how QSB is different on different station, when peak is on
> > my side, deep gos to John and VV
> >
> > thanks, 73 cul dado E74AW
> >
> > Дана
> > 06.02.2014 06:21, James Wolf је написао:
> >
> >> Jose,
> >>
> >> I am only
> > presenting the possibility that if the ionosphere (where 160
> >>
> > propagation happens) isn't uniformly smooth and instead consists of
> > "warps,
> >> wrinkles and tilts" that in a *dynamic ionosphere*, this could
> > be at least
> >> one reason we are experiencing slow fades.
> >>
> >> Elliptical
> > polarization, assuming that it is ever changing, could provide
> >> yet
> > another degree of selective fading.
> >>
> >> I'm don't think I *totally*
> > understand why KL7AJ says that "at HF the
> >> ionosphere forbids the
> > propagation of linearly polarized signals". If at
> >> the magnetic
> > equator, and signals were East to West to equal the earth
> >> magnetic
> > tilt of the signals, it seems that at an instance in time that a
> >>
> > linear polarized signal could happen. But that may be nit picking.
> >>
> >>
> > Jim - KR9U
> >>
> >> From: JC N4IS [mailto:n4is@comcast.net]
> >> Sent:
> > Wednesday, February 05, 2014 10:45 PM
> >> To: jbwolf@comcast.net; 'Tom
> > W8JI'; herbs@vitelcom.net;
> >> topband@contesting.com
> >> Subject: RE:
> > Topband: circular polarization on 160m
> >>
> >> James
> >>
> >> You brought a
> > good article about HF propagation, however the behavor on 160m
> >> is
> > different from HF. If you check on the KL7A arcticle figure 1 what is
> >>
> > happening between 1 and 2 MHz you can see that the green and red does
> > not
> >> behaivor the same way as above 2 MHz.
> >>
> >> This subject is more
> > complex because there us no shirt answer, actualy
> >> between 1 and 2 MHz.
> > the ionosphere does not support linear polariration
> >> wave. The wave are
> > actualy eliptical and not circular for most directions.
> >>
> >> You can
> > check the long answer on the "must read book" from NM7M . R Brown
> >> 'The
> > Big Gun's Guied to Low Band Propagation" . Magneto-iomic Theory pag 47
> >>
> > to 56 ; and Power coupling pag 57.
> >>
> >> Thanks to Karl. K9LA, the book
> > is available on his also must read site on
> >> the 160m link
> >>
> >>
> > http://k9la.us/html/160m.html [1]
> >>
> >> Regards
> >>
> >> JC
> >>
> >> N4IS
> >>
> >>
> > _________________
> >> Topband Reflector Archives -
> > http://www.contesting.com/_topband [2]
> >
> >
> > Links:
> > ------
> > [1]
> > http://k9la.us/html/160m.html
> > [2] http://www.contesting.com/_topband
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> > Topband Reflector Archives - http://www.contesting.com/_topband
> >
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--
73 Joel W5ZN
www.w5zn.org
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