Hello Nick,
I have not had much time to be contesting, however have had some
experience with loops and to a lesser degree verticals.
I would second Billy's suggestion. Last antenna I had the chance to
play with on 75 was a 2 element delta loop. It played very well.
Given the chance I would want to have one of each. The loop primarily
because it is a bit quieter (especially during the summer). In some
cases it may be worth transmitting on the vertical and receiving on the
loop. If you have the real estate long wires for receiving can be worth
the time spent doing the construction.
What I can't quantify is what gain / pattern I had with the delta. It
was interleaved with guy lines that probably made the pattern a bit
messy. I can say it played well.
The paper from the presentation at Dayton mentioned below was quite
informative. Thanks to Billy for posting that.
Dave
KU4B
On Sun, 2008-06-08 at 21:34 -0400, Billy Cox wrote:
> >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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