Re: Topband: circular polarization on 160m -BTW

[Carsten Esch <carsten.esch@appello.de>]

... circular polarization is standard on 23cm, 13cm and 9cm EME. For 10 
GHz it is becoming more popular (because there are now feed designs that 
can be (more) easily reproduced on this band.
73ss

Carsten, DL6LAU (QRV on 23cm, 13cm, 10GHz and 24GHz EME @ DL0SHF)

Am 12.02.14 19:47, schrieb Charlie Cunningham:
> 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
> > _________________
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> > http://www.contesting.com/_topband [2]
> >
> >
> > Links:
> > ------
> > [1]
> > http://k9la.us/html/160m.html
> > [2] http://www.contesting.com/_topband
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> >
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