I have 3 TH7s on one tower - 25, 40 and 76 ft. There are plenty of times
the TH7 at 25 ft is better into Europe than either of the 2 higher
antennas or the upper 2 phased, on 10m. The lowest antenna has
never been better on 15 or 20, but the antenna at 40 ft has been better
into EU than the one at 76 ft alone, as well as better than the upper 2
phased (though not very often on 20m).
30 years ago, high, long boom antennas were thought to be best. This
has since been shown to be incorrect by both experience and computer
models. As someone else pointed out earlier, that's why the big guns
have multiple antennas at multiple heights for any given band.
Barry W2UP
On 10 Jan 2002 n4kg@juno.com wrote:
>
> Those observations seem reasonable to me.
>
> If you had 2 high stacks on 10 and 15M with the bottom antenna
> at 40 ft, I expect you would observe more incidents of the low
> antenna being better. Location and distance are also a factor.
> W4ZV reports less wave angle variation to Europe from NC than
> he calculates for my location in Alabama.
>
> Tom N4KG
>
> On Thu, 10 Jan 2002 "ted demopoulos" <kr1g@hotmail.com> writes:
> >
> > I've got 4/4 on 20m at 100 and 50 feet. The stack is usually louder
> > to Europe BUT:
> >
> > often in the afternoon, maybe 1900z or so, the lower antenna is
> > signifantly better, a couple of "S-Units." I rarely see significant
> > benefits to the lower antennas alone in the 10m (25/50/75') or
> > 15m (35/70/105) stacks.
> >
> > 73
> > Ted, KR1G
> >
> >
> > >From: Pete Smith <n4zr@contesting.com>
> > >To: <TOWERTALK@contesting.com>
> > >Subject: Re: [TowerTalk] Are higher HF antenna's really better?
To: <towertalk@contesting.com>
> > >Date: Thu, 10 Jan 2002 10:29:05 -0500
> > >
> > >
> > >At 03:12 PM 1/10/02 -0000, Sain'T Tom wrote:
> > > >
> > > > I once used 2 of the same 3 element 15 meter yagis
> > simultaneously
> > >from
> > > >my old QTH in South Carolina. One was at 70 feet on the tower
> > top and
> > >was
> > > >rotatable. The other was fixed on Europe at 40 feet. Both had
> > >electrically
> > > >equivalent (same electrical length) feed lines of RG213.
> > > >
> > > > Reports from Europe generally, but not always, gave the stack
> > a
> > >slightly
> > > >stronger signal report. The lower sometimes would be reported
> > just as
> > > >strong as the upper, but NEVER was it reported that the lower was
> >
> > >stronger.
> > >
> > >I think band and sunspot cycle phase have a lot to do with this.
> > >Certainly, as N4KG says, if you can have multiple antennas there
> > are lots
> > >of reasons to do so, including but not limited to stacking. But if
> > you can
> > >only have one, and particularly if it is a tribander, somewhere
> > between 75
> > >and 100 feet is very nice indeed, but I'm not sure it makes a lot
> > of
> > >difference which end of that range you're at.
> > >
> > >My 2-high stack of C-3Es is at 97 and 69 feet, and I have only
> > heard
> > >signals louder on the lower antenna than the upper one, on any
> > band, on one
> > >or two occasions. My hunch is that if I had a third antenna at
> > 32-33 feet,
> > >there's a greater chance that I'd notice differences between single
> > >antennas, but most of the time, the whole stack together would
> > still be
> > >best.
> > >
> > >73, Pete N4ZR
> > >
> > >The revised World Contest
> > >Station Database
> > >is online at www.pvrc.org
> > >
> > >
> > >
> > >
> > >
> >
> >________________________________________________________________________
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> > >
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> >
> >
> >
> >
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> >
> >
> ________________________________________________________________________
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> Problems: owner-towertalk@contesting.com
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--
Barry Kutner, W2UP Internet: w2up@mindspring.com
Newtown, PA Frankford Radio Club
________________________________________________________________________
This list is sponsored by the new eHam.net Store. When you buy products
like ICE filters, Array Solutions StackMatch, or M-Squared Antennas from
the eHam Store for the same price you pay direct, a portion of the sale
price goes to support this list. Check it out at http://www.eham.net.
-----
FAQ on WWW: http://www.contesting.com/FAQ/towertalk
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