With such a large tower at my disposal, and evidently access to its top at
least to attach the wires and transmission line, I'd probably do something
else.
>From the UK, the US will peak in various directions depending upon where you
wish to work, and the narrower the pattern, the more evident that becomes.
Example Stateside is that VK can peak anywhere from NW to SW, and everything
between, because that's our viewing angle towards VK from here. With one
narrow pattern antenna, I'm not sure which part of VK I'd choose.
One trick that comes to mind with a single high feedpoint antenna made of
wire would be to make a sloping rhomboid aimed into the ground
(intentionally) at a critical angle to bounce off the earth and back up
towards the ionosphere to make the signal land in about the middle of the
U.S. The angle is simple trigonometry. And this approach is not new, it's
used and quite popular in shortwave broadcast work.
WB2WIK/6
"If everything seems under control, you're just not going fast enough." -
Mario Andretti
> -----Original Message-----
> From: n4kg@juno.com [SMTP:n4kg@juno.com]
> Sent: Tuesday, December 03, 2002 7:49 AM
> To: TOWERTALK@contesting.com; g0hgw@yahoo.com
> Subject: Re: [Towertalk] Vee beam
>
> Rob,
>
> I've had considerable experience with single element
> Long Wire Antennas, mostly on the WARC Bands where
> an 80M dipole acts as a current fed Long Wire of odd
> multiples of 1/2 WL. These are VERY effective antennas
> when the major lobes are aligned with the desired target
> area(s).
>
> From that experience (and modeling) I note that Sloping Wires
> generally have poor performance unless great care is taken to
> align a major lobe with the desired takeoff angle.
>
> That said, your BEST bet would be to select a wire length
> and play with computer modeling to obtain a useful design.
> You will want to consider the Length of each wire, the Angle
> between the wires, and the angle between the wires and ground.
>
> Note that high antennas are typically good band openers
> and closers, LOW antennas (40 to 60 ft) are often BEST
> during midday when the sun is up.
>
> W3LPL (and others) have found that 10M horizontally polarized
> antennas at 200 ft seem to cover ALL angles well since there
> are so many very narrow lobes separated by very small angles.
> I expect that irregularities in the foreground fills in the
> narrow nulls that would be expected from reflections
> from a perfectly flat foreground.
>
> Tom N4KG
>
> On Tue, 3 Dec 2002 (GMT) =?iso-8859-1?q?Robert=20Thain?=
> <g0hgw@yahoo.com> writes:
> > Hi,
> >
> > I have access to a 40-50 meter water tower and would
> > like to put out a big signal State side during the
> > ARRL 10m contest.
> >
> > I was thinking about a V beam.
> > This is where the apex of the V is up heigh and the
> > tails of the V ( Usually wavelengths long ) run
> > diagonally to the ground.
> >
> > However I just cant find ANY information on this
> > antenna.
> >
> > Where can I find some info ?
> > OR
> > Is there a better antenna I could make from wire and
> > make use of this height ?
> >
> > Thanks
> > Rob,
> > G0HGW
> >
> > PS how do does one do a search on the Archives on
> > TowerTalk without going though them all manually ?
> >
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>
>
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