[Towertalk] OPTIMIZED ANTENNA SYSTEM

[Guy Olinger, K2AV]

A 20m eight element wire yagi on 168' catenary (true wide spaced)
fixed on EU is far narrower than anything below. In combination with a
higher 4 el swung 350 for JA, UA9, UA0, it covers very well.

There is an unproved implicit assumption in many of these discussions:
that a laser width beam (if you could make an antenna sharp enough on
HF) would show up at the other end as a sharply defined spot source on
the horizon.

Accumulating experience seems to indicate the opposite, that the laser
width beam would show up at the other end looking like cloud-reflected
night light from a city 25 miles away. Or that the laser width beam
would in fact cover twenty or even thirty degrees at the far end.

Point being that the scattering may make beam width discussions turn
on transmit gain, and reducing receive aperture to reduce fading.

73, Guy.


----- Original Message -----
From: <n4kg@juno.com>
To: <TOWERTALK@contesting.com>
Sent: Friday, November 15, 2002 8:18 AM
Subject: Re: [Towertalk] OPTIMIZED ANTENNA SYSTEM


> N4KG responses inserted below.
>
> On Fri, 15 Nov 2002 David Robbins" <k1ttt@arrl.net> writes:
> > Optimum for what? And from where?
>
> My point exactly.  I expect everyone's idea of
> optimum depends on their own persepective.
> >
> > For my use I would consider a stack of 6's to be too narrow for
> > contesting from the northeast.  Up here a stack of 4's is probably
> > better to cover more of Europe at one time.  From farther west
maybe
> > the 6's would be better as the angular spread to cover Europe for
> > contesting is smaller, or if you are dxing, ragchewing, or
handling
> point to
> > point traffic the 6's may be reasonable.
>
> The 6L models on 0.75 WL booms in W2PV's
> Yagi Design Book show a -3 dB beamwidth of 50+
> degrees.  Is that too narrow from W1?
>
> The 3L models on 0.28 Wl booms show a -3 dB
> beamwidth of <70 degrees.
>
> Tom  N4KG
> >
> > David Robbins K1TTT
> > e-mail: mailto:k1ttt@arrl.net
> > web: http://www.k1ttt.net
> > AR-Cluster node: 145.69MHz or telnet://dxc.k1ttt.net
> >
> >
> > > -----Original Message-----
> > > From: towertalk-admin@contesting.com [mailto:towertalk-
> > > admin@contesting.com] On Behalf Of n4kg@juno.com
> > > Sent: Friday, November 15, 2002 03:10
> > > To: TOWERTALK@contesting.com
> > > Subject: [Towertalk] OPTIMIZED ANTENNA SYSTEM
> > >
> > > My vote for the optimum antenna system is for:
> > >
> > > 4 High Stacks of 6L Monobanders on 3/4 WL booms
> > > spaced equally on 3WL high rotating towers, for EACH
> > > band, with ALL combinations instantly switch selectable.
> > >
> > > Make that a stacked pair on 40M on a 1.5 WL high tower
> > > (200-ft)
> > >
> > > OH, did I hear someone complain about the price?
> > > Or space requirements?
> > >
> > > Well then,  start making COMPROMISES
> > > that fit YOUR requirements.  :-)
> > >
> > > Tom  N4KG
> > >
> > >
> > >
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>
>
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