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Re: Topband: Non-resonant receive antennas

To: "'Top Band Contesting'" <topband@contesting.com>
Subject: Re: Topband: Non-resonant receive antennas
From: "Tom W8JI" <w8ji@w8ji.com>
Reply-to: Tom W8JI <w8ji@w8ji.com>
Date: Sat, 20 Dec 2014 10:01:15 -0500
List-post: <topband@contesting.com">mailto:topband@contesting.com>
This is almost the way it worked here just at sunrise, both transmitting and receiving, except after sunrise the vertical hung in longest here. The brief and unpredictable window of horizontal superiority at this location is why I eventually just let the horizontal antennas all fall apart.

The pattern was true for both high (~300 ft) and low (less than 150 ft) dipoles. We would get beat all the time in 160 pileups using a high dipole in contests on the second station, so much that I just took that antenna out of the selections.

At this location, when the horizontal was good the verticals were still workable. So the horizontals never really extended anything, they just were better. The exception was during solar storms, where sometimes the verticals were poor compared to the horizontals for extended periods.

73 Tom

If the band was open before my local sunrise (not always the case!), the
verticals would always outperform the dipole by a large amount. However, as
soon as we hit sunrise, the dipole would suddenly start equaling and then
outperforming the verticals. The transition would take place in a matter of a few short minutes. Past sunrise, DX signals would drop into the noise on the verticals but would continue to hang in on the dipole. The dipole would sometimes extend the opening for me by 5 to 15 minutes, allowing me to make
some contacts (mainly JA and VK, if the band was open in those directions)
that would not have been possible with the vertical array. Sometimes the DX
would be virtually inaudible on the verticals but Q5, although not strong,
on the dipole.

What is rather interesting, however, is that in the winter seasons of
2012-2013 and 2013-2014, this dipole advantage became non-existent.  The
dipole was never even close to the verticals, either before or after
sunrise. It caused me to go outside a number of times to see if the dipole
had fallen down, but that was never the case.  Evidently the propagation
mechanisms at work around sunrise have changed from a few years ago, at
least at my QTH.  So far in the 2014-2015 season, the dipole has still not
provided any receiving advantage around sunrise.

I generally don't operate much around local sunset, but I have never seen
any dipole advantage at sunset.

73, John W1FV

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