[50mhz] Polarization

[Bill VanAlstyne]

I asked that same question of some local guys a few months back, as I have a
Radio Schlock Discone also, which I painstakingly tweaked up to resonate at
50.125. It is vertically polarized. Thank heavens I now have a real antenna on
this band! <g> But I did manage to work 85 grids with it, amazingly enough.

Basically, this antenna is practically a dummy-load at 50 MHz (base-loaded
radiator is less than 1/4 wavelength), so the fact that it outperforms the halo
on a beacon means either a) there is something wrong with the halo or its
installation, or b) you are listening to the beacon via ground wave (rather than
atmospheric propagation) and you are cross-polarized with it when using the
horizontally-polarized halo.

Sporadic-E and other modes of atmospheric propagation twist polarization all
over the place, so it's usually not a factor in these cases. But ground waves
tend to maintain their polarization as long as they don't spend too much time in
proximity to things (the earth, mountains, buildings, etc.) that twist them up.
That's why polarization distortion on ground wave tends to increase with
distance.

Most 6M beacons use omnidirectional vertical antennas, though some do use
horizontally polarized loops, dipoles, or even yagis.

A good resource for 6M beacons is at http://www.keele.ac.uk/depts/por/50.htm
(G3USF's Worldwide List Of 50MHz Beacons). This resource will tell you, in many
cases, what kind of antenna the beacon is running and how much power.

Bill / W5WVO



----- Original Message ----- 
From: "Marvin L. Jones" <jonz@config.com>
To: "RJ Mattson" <rjmattson@hvi.net>
Cc: <50mhz@mailman.qth.net>
Sent: 04 September, 2003 10:27 AM
Subject: Re: [50mhz] Polarization


> On Thu, 4 Sep 2003, RJ Mattson wrote:
>
> >I am comparing a Saturn 6 halo with a Radio Shack Discone
> > antenna on a distant 6m beacon (K2ZD/B).
> >The discone wins easily at the same height.
> >Could this be because of polarization?
> >Is a discone vertically polarized?
>
> For what values of "distant"?
> Yep.
> Yep.
> Dunno about the beacon's polarization at this time.
>
> 73
> Jonesy
> Moderator: Ray Brown, KB0STN
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