>From: "w4gkm@juno.com" <w4gkm@juno.com>
>Subject: [TCG] 80 vertical
Excellent topic Nick ... here's my 2 cents ...
>What I want to do is put up a 80 meter vertical using
>Rohn 25 and put a stinger on the top section that can
>be lower or raised for frequency change on that band.
Using the 25G, you may find that the bandwidth is fine
without the need for any adjustable stinger ... check
the archives of TowerTalk, and I believe you will find
others who have constructed similar verticals before.
Some of the previous ARRL antenna publications and
also ON4UN's books may prove to be useful for this.
>I have the tower and fiberglass rods to insulate with
>but my question is, is it worth the trouble or will it
>be that much of an improvement over a loop I have @ 50'.
Tough question to answer, not knowing if your loop is
primarily horizonally or vertically polarized ... I'll
go with guessing it is primarily horizonal, and if so
then would vote a YES as to the vertical <with a good
ground system> being a useful option, or improvment for
the longer distances there. As a side benefit, it might
also tend to fill in on any nulls the 50' loop might have.
>If you have some input on this I would also like to
>know how far up I should put the insulators from the
>ground. Should it be in the ground radials or elevated
>radials? If so how many for each installation.
I ran a 8' elevated 80m4x for over 12 years. It's down now
for rebuilding and will be ground mounted next time. There
is enough solid, valid data now from respectable sources
such as W8JI, ON4UN, and others to resolve this debate.
My summary is the ground mounted system, with about 32-40
radials, as long as you can make them, up to about 0.4w in
length, is going to be the best return for the investment.
While the old array had a good pattern, and worked well,
over many times and with many tests with others, the ground
mounted systems tended to be the stronger signals.
So while the elevated radials "work" ... the subjective
question becomes "Yes, but how well REALLY do they work?"
If you can/want to put up say 16-24 elevated radials then
you are in the same level of ground loss as the 32-40 ones
on the ground. Elevated is a LOT more work to keep up in
the air and working. Been there, done that, not again is
my conclusion with a much less elaborate elevated system.
If one thinks 1-4 elevated radials at 8' - 25' above ground
is the same as 120 on the ground. Two words: Dream On. B->
Sure it may "work" but at what level of performance?
>>I'm just trying to improve my signal and reception for DX
>on 80 meters as some of the RTTY contests favor making DX
>contacts on that band. I'm satisfied as well as I can be
>with the other bands but on 80 I just can't seem to compete.
Then keep the loop and ADD the vertical ... and consider some
form of a receiving antenna, the K9AY, EWEs, Beverages/etc
can make ALL the difference in the world as to QSO or no QSO.
<and also watch for any interaction between the loop, and any
other tower(s) you have there, especially other towers as they
can act as directors or reflectors to the single vertical.>
Another idea ... is to load one of the existing towers for
80m, either ground mounted of via N4KG's idea. That worked
well here on 160m for many years too. Not perfect but much
better than the typical low dipole 160m setup.
Some details on Tom's idea can be found here:
http://www.qth.com/ka9fox/n4kg_antenna.txt
If you REALLY want to ramp up you low band signal, here's
an idea or two to consider from a recent Dayton presenation:
http://www.kkn.net/dayton2008/multi-element%20lowband%20verticals%206.pdf
>Thanks in advance guys and all suggestions welcome
>Nick
>W4GKM
Hope this helps!
73 de Billy, AA4NU
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