G’day
Thanks to Carl K9LA for his excellent insights – as always – in how 160m prop
works.
Having been active on 160m from Western Australia for some 23 years, once thing
I’ve learnt is that in south-western Western Australia and at a latitude of -31
degrees or so, with the poor soil conductivity we have here, is that antennas
that have predominantly vertical polarisation are sadly poorer for DX working
than those that are predominantly horizontally polarised.
That is why Mike VK6HD (SK), Phil VK6ABL/6GX and I all have predominantly used
flat-top or inverted vee dipoles.
Equally as Tom W8JI found that his dipole at 300’' feet high (to quote Guy
K2AV) “would never beat a commercial-AM-BC-quality vertical and radial field,
and only infrequently would equal it”, Mike VK6HD spent at least a year making
A/B comparisons between an inverted vee dipole (at 90 feet) and a quarter-wave
inverted-L with a 85’ vertical section over 132 x 132’ radials and found that
mostly the inverted vee dipole was ‘'2 ‘S’ points better than the inverted L on
both receive and transmit.
Mike also found that infrequently, prior to around one and a half to two hours
before sunset here – and after one and a half hours after sunset, the inverted
L was better than the inverted vee.
After about two years of consistently getting the same results , Mike took the
quarter wave inverted-L down.
After entirely using vertical/inverted-L antennas in the UK as G3ZZD for DXing
on 160, 80 and 40m, I was initially shocked about how poorly they worked in the
lower south-west of WA. My earth system here currently is around 30 x 66 to
100 foot long radials and I’ve also used a large number of counterpoise
systems, including the excellent K2AV one.
My results here have mirrored Mike’s – consistently and over the solar cycles.
Les Moxon G6XN once said the best thing to do was to try both horizontal and
vertically polarised antennas wherever you live and use which worked best. I
think Les’ advice is still very relevant. ;-)
PS As Luke says, summer in VK is a much more interesting time to work 160m than
the winter. Clearly, everything is upside down, down here.
Vy 73
Steve, VK6VZ (licensed as G3ZZD in 1971)
From: Carl Luetzelschwab <carlluetzelschwab@gmail.com>
To: topband@contesting.com
Subject: Topband: 160m polarization and elevation angles
Message-ID:
<CAAx1FFF_vAb-jOADZPAoceMqT7yN6Hau__TOa4DCY+B0+V=zWA@mail.gmail.com>
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Polarization - As Jerry K4SAV stated, the electron gyro-frequency plays an
important role on 160m since our ionosphere is immersed in a magnetic field
- it also affects ionospheric absorption and refraction. For those of us at
mid to high latitudes, vertical polarization on 160m is *theoretically*
optimum since it couples the most energy to the limiting polarization at
the entrance to the ionosphere. I
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