The equivalence is easier to explain with the centers high. But...
The ground reflection gain (or lack of it) normally quoted when
analyzing this situation is only really in play to the specified db
with a more or less flat ground to reflect off of for a ways out.
There are many terrain configurations that would effectively nullify
ground reflection at angles useful for DX, the bulk of reflection
being too high a takeoff angle to be of much use.
If one was in such a situation (taking away the ground reflection
advantage) and the centers of the vertical dipoles were high enough to
avoid heavy e-plane ground penetration loss, the two would play pretty
much alike.
73
----- Original Message -----
From: "Larry L Lindblom" <llindblom@juno.com>
To: <k2av@contesting.com>
Cc: <llindblom@juno.com>; <towertalk@contesting.com>
Sent: Saturday, October 12, 2002 3:38 PM
Subject: Re: [Towertalk] 40M 4 Sq vs. 2 el Yagi at 70 ft
> Center of the lazy vees were about 90 ft. Since then 2 more TH-7s
were
> added to the tower with the 4 square dropped lower and the centers
only
> about 30 feet. No major difference in performance.
>
>
> On Sat, 12 Oct 2002 14:53:58 -0400 "Guy Olinger, K2AV"
> <k2av@contesting.com> writes:
> > Just for clarity, what you described is not a 4-square in the
> > ordinary
> > sense. The current maximum in your conductors is many feet off the
> > ground. (How high was the center of the lazy vee dipoles?) A
typical
> > 4
> > square has the current max right at or a few feet off the ground.
> > If
> > the centers were 70-100 feet, it WOULD play like a 2 element
shorty
> > forty.
> >
> > A bit of apples vs. oranges here.
> >
> > 73, Guy.
> >
> > ----- Original Message -----
> > From: "Larry L Lindblom" <llindblom@juno.com>
> > To: <k2av@contesting.com>
> > Cc: <towertalk@contesting.com>; <wz7i@arrl.net>
> > Sent: Saturday, October 12, 2002 10:38 AM
> > Subject: Re: [Towertalk] 40M 4 Sq vs. 2 el Yagi at 70 ft
> >
> >
> > > A couple years back I had an M2 2-el 40 on tower #2 at 128 ft
and
> > a
> > lazy
> > > vee vertical dipole 4 square for 40 meters on tower #1 below a
> > TH-7
> > which
> > > was at 123 ft. In A/B comparisons there was no clear winner
> > between
> > the
> > > two 40 meter antennas. Which of the antennas was "slightly
> > better"
> > than
> > > the other varied from night to night or the path involved.
> > >
> > > Of course everyone on the reflector with a 2-el 40 told me there
> > must be
> > > something wrong with mine. But, none of those comments seemed
to
> > be
> > > based on those people doing an A/B comparison. In the end maybe
> > it
> > > simply proved on can never have too many antennas on any band!
> > >
> > > 73
> > >
> > > W0ETC
> > >
> > >
> > > On Fri, 11 Oct 2002 22:40:34 -0400 "Guy Olinger, K2AV"
> > > <k2av@contesting.com> writes:
> > > > A two element 40 meter "shorty forty" at 70 feet and up is a
> > fixture
> > > > among contesters that can't put up the monsters.
> > > >
> > > > Suggest to any one of them that they should replace it with a
> > > > four-square and see what reaction you get.
> > > >
> > > > A forty 4 square is what you do if the shorty forty is out of
> > the
> > > > question, and dipoles off the tower at 65 feet mess up the
> > > > tribander.
> > > >
> > > > 73, Guy.
> > > >
> > > > ----- Original Message -----
> > > > From: "Wes Cosand" <wz7i@arrl.net>
> > > > To: <towertalk@contesting.com>
> > > > Sent: Friday, October 11, 2002 8:59 PM
> > > > Subject: [Towertalk] 40M 4 Sq vs. 2 el Yagi at 70 ft
> > > >
> > > >
> > > > > K7LXC's recent comment about yagis vs. 4 square arrays got
me
> > > > > thinking. Has someone done a careful comparison of these
two
> > > > antennas for
> > > > > 40 meters?
> > > > >
> > > > > I have relocated and have to build a new station and I am
> > torn
> > > > between
> > > > > these two alternatives. Although performance is important,
> > the
> > > > station
> > > > > will not necessarily be used for contesting. The initial
> > cost
> > is
> > > > not as
> > > > > important as reliability and freedom from maintenance.
> > > > >
> > > > > I have previously had a 40M 4 square that was carefully
> > installed
> > > > with the
> > > > > DX Engineering phasing network. I was never tremendously
> > > > impressed
> > > > with
> > > > > the performance but I never had the opportunity to compare
it
> > to
> > > > a
> > > > > yagi. And it certainly didn't require much care and
> > feeding--
> > it
> > > > just worked.
> > > > >
> > > > > I had decided to replace the vertical array at the new
> > station
> > > > with
> > > > a 2
> > > > > element yagi at 70 or 80 feet, perhaps 12 feet above my five
> > band
> > > > > beam. But the 40M yagi means that the total installation
> > will
> > be
> > > > much
> > > > > higher than the 50 or 60 feet tower I could get by with if
20
> > > > meters
> > > > was my
> > > > > lowest freq antenna. The tower and rotor must be
> > significantly
> > > > > beefier, and I am concerned that it will add to the
> > maintenance
> > > > > needs. (The tower must be self supporting.)
> > > > >
> > > > > So why did ON4UN's 1998 survey indicate that among the top
> > 100
> > > > DXers
> > > > who
> > > > > responded about 40M antennas, 35% of them used 2 el yagis
and
> > > > only
> > > > 7% used
> > > > > phased verticals? ON4UN said his survey indicated that at
> > that
> > > > time
> > > > > Cushcraft and Hy-Gain 2 element yagis were "extremely
popular
> > on
> > > > 40meters".
> > > > >
> > > > > Wes, WZ7I
> > > > > _______________________________________________
> > > > > AN Wireless Self Supporting Towers at discounted prices,
> > > > > See http://www.mscomputer.com
> > > > >
> > > > > Wireless Weather Stations now $349.95. Call Toll Free,
> > > > > 888-333-9041 for additional information.
> > > > > _______________________________________________
> > > > > Towertalk mailing list
> > > > > Towertalk@contesting.com
> > > > > http://lists.contesting.com/mailman/listinfo/towertalk
> > > > >
> > > >
> > > >
> > > > _______________________________________________
> > > > AN Wireless Self Supporting Towers at discounted prices,
> > > > See http://www.mscomputer.com
> > > >
> > > > Wireless Weather Stations now $349.95. Call Toll Free,
> > > > 888-333-9041 for additional information.
> > > > _______________________________________________
> > > > Towertalk mailing list
> > > > Towertalk@contesting.com
> > > > http://lists.contesting.com/mailman/listinfo/towertalk
> > > >
> > > >
> > > _______________________________________________
> > > AN Wireless Self Supporting Towers at discounted prices,
> > > See http://www.mscomputer.com
> > >
> > > Wireless Weather Stations now $349.95. Call Toll Free,
> > > 888-333-9041 for additional information.
> > > _______________________________________________
> > > Towertalk mailing list
> > > Towertalk@contesting.com
> > > http://lists.contesting.com/mailman/listinfo/towertalk
> > >
> >
> >
> > _______________________________________________
> > AN Wireless Self Supporting Towers at discounted prices,
> > See http://www.mscomputer.com
> >
> > Wireless Weather Stations now $349.95. Call Toll Free,
> > 888-333-9041 for additional information.
> > _______________________________________________
> > Towertalk mailing list
> > Towertalk@contesting.com
> > http://lists.contesting.com/mailman/listinfo/towertalk
> >
> >
>
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