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[TenTec] R-7000 Vertical Experience

To: <tentec@contesting.com>
Subject: [TenTec] R-7000 Vertical Experience
From: rohre@arlut.utexas.edu (rohre)
Date: 16 Oct 1997 15:08:24 -0500
Testing a dipole against a vertical at less than the other side of a continent
is testing apples vs. oranges.  There are a lot of variables in far field or
skip testing. Modeling might be the better test against isotropic sources.
Take off angle maxima for the vertical or dipole is site dependent, and in
case of a ground mounted quarter wave vertical, ground loss dependent.  You
have to test with many stations, at various times of the day to derive some
envelope of performance for either antenna.  Under some band conditions, my
vertical holds the band on 20M better than other antennas, at other times, it
is different.

Yes, if you are horizontally polarized, and the test vertical station switches
to the same, you will hear a louder signal.  But, after some skip, it can be a
different matter, for the heights that most dipoles are erected today.

Yes, it is desirable to have an open wire fed dipole as long as your real
estate dimensions allows. That is great for all band, and close in working
within the country. But you probably want at least one other type of antenna
to give you the "edge" that varying conditions under DX working will present. 
Many cannot put up a beam and rotor, and the all band vertical, placed as an
elevated vertical antenna, (even only 6 feet above ground as my Gap Titan is),
presents a self contained antenna with counterpoise that out performs any
dipole I have been able to have over mediocre earth conductivity. It would be
even better as a full quarter wave on all bands, but does probably outperform
shorter verticals, at its 26 foot active form.  As the Titan uses linear
decouplers rather than coils and capacitors, it is probably more effiecient
than a trap vertical.  Its feed system shields the first length of coax and
adds a lower noise character to this vertical.  That was observed in several
reviews by different people.  Better signal to noise can be an improvement
just as important as gain, as you can't work them if you don't hear them.

Bottom line, no one antenna will do it all if you like to work DX and close
The dipole can be home built at low cost, but requires an antenna transmatch
and open wire feed to work all bands. It requires some real estate and a
vertical support, which does not help it work.  On the all band vertical use:
I don't need a tuner to cover all the bands except I do have to pick and
choose my segment on 80M.
My vertical support is my antenna, and thus low profile as Conway stated. 
Each has a very good place, and proper application of the right vertical will
give much better results than you often hear about. Avoiding ground loss is
key.  Check out what the DX stations in poor countries use.  Those in the DX
standings are often using a vertical.
If DX is not your thing, maybe a dipole is all you need.  But more antennas
gives you a lot of fun, and you are prepared for anything.  I have had a lot
of fun with a WARC G5RV with an extra modification, (horizontal ladder line
section), and with the Gap Titan.  If the sunspots co-operate, both are hot,
except 15m and 30m are harder on the G5RV, because of SWR.
Whether you are in an area where antennas ice up could be a factor in choosing
which antenna will survive.  My triple wall Titan has bowed over in wind gusts
and come right back up.  It survived 70 mph winds that took down 3 trees
around it in May.

That is one of the big fun things in radio, playing with all types of
If you are good with your hands, you can replicate the best of the commercial
ones and save a lot of money.

73, Stuart K5KVH

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