[TowerTalk] Insulating tower

[Guy Olinger, K2AV]

What a four square has going for it, if you can do it right, is somewhat
more gain (not huge difference, as Mauri points out) and a phenomenal
rejection of the rear quadrant, which can be worth a bundle if the
prevailing noise is in opposite directions from the opening of the
moment. In the southeast USA, when on Europe, it nulls the noise off the
backside. Really quiets things down.

- - . . .   . . . - -     .   . . .     - - .   . - . .

73, Guy
k2av@contesting.com
Apex, NC, USA

----- Original Message -----
From: Maurizio Panicara <i4jmy@iol.it>
To: Major Ron <majrabsr@rconnect.com>; towertalk
<towertalk@contesting.com>
Sent: Tuesday, April 04, 2000 4:44 PM
Subject: R: [TowerTalk] Insulating tower


>
> A 75ft tower is a too short radiator for a gamma match.
> An omega match could do it but won't fix inherent antenna losses, due
> to a low Rr, and ground losses.
> Also a linear loading won't improve antenna performances and an extra
> device for matching to 50 Ohms will be required.
> Best solution is probably to add enough capacitive top loading (useful
> to rise Rr and efficiency) so electrically lenghtening the antenna
> until a gamma match can be used.
> The top loading can be in the form of some sloping copper wires of
> appropriate length.
>
> Generally speaking, a 4 square is not such an easy array to make
> working properly, expecially when antennas are tightly coupled and
> short.
> In my experience I've rarely seen 4 square arrays with a real and
> substantial gain over a symple 2 phased array.
> I got convinced this is because of ground planes that do not have
proper
> characteristics to satisfy the 4 square needs.
> With short radiators ground plane is never good enough and often the 4
> square gain is only marginal.
> With not resonant short verticals a better gain is often obtained
> focusing on a single element (making it longer, either phiscally and
> electrically) and minimizing the ground losses than phasing multiple
> antennas with an insufficient/improper ground plane.
>
> 73,
> Mauri I4JMY
>
>
>
> ----- Original Message -----
> From: Major Ron <majrabsr@rconnect.com>
> To: towertalk <towertalk@contesting.com>
> Sent: Tuesday, April 04, 2000 3:16 AM
> Subject: [TowerTalk] Insulating tower
>
>
> >
> > Hi Guys,
> >
> > I've been reading this newsgroup for a couple months and have been =
> > really impressed with the knowledge available.
> >
> > I recently acquired and moved to 20 acres in SW MN. Now have about 5
=
> > acres for antennas.
> >
> > I want to build a 4-square array for 160M. Already have 4ea 60-ft
Rohn =
> > 20 towers and 4ea R/S 19-ft telesoping masts, which will be attached
to =
> > the towers for 75-ft total height.
> >
> > Now the problem: How can I insulate the towers from ground?
> >
> > I need a CHEAP solution.
> >
> > Tnx & 73,
> > Ron, KA9ALC
> >
> >
> > --
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>
>
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>


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