Don and Tom,
My understanding of the operational characteristics of the Beverage antenna
is that the use of sloping terminations eliminates the requirement of
special efforts to cancel the reception of vertically polarized signals in
ALL directions that would be picked up by a few feet of vertical termination
wire off a pole.
I understand that the vertically polarized signals from the "front" of the
antenna will be received equally well by the sloping termination of the
antenna or a vertical termination wire. BUT, the sloping termination
continues the characteristic of the Beverage antenna, in that it
predominantly responds to signals in the plane of the axis of the antenna.
The vertical termination wire allows vertically polarized signals from ALL
directions to degrade the performance of the Beverage antenna. I disagree
that the quantity of signal induced in this manner is not detrimental to
performance. All you have to do is insert a short piece of wire into the
antenna jack of your receiver to know how much signal that short piece can
deliver.
I believe that small amount of signal from unwanted directions can, in many
instances, totally obsure a weak signal from the desired direction.
Comments?
Milt, N5IA
----- Original Message -----
From: "Donald Chester" <k4kyv@hotmail.com>
To: <topband@contesting.com>
Sent: Monday, December 08, 2003 11:02 PM
Subject: Re: Topband: Cone of Silence
>
> >I am not personally
> >convinced that there is really a "cone of silence", but why not use these
> >lengths in case there is such a beast. My impression is that when we
adjust
> >the exact length of the beverage the most predominate effect is to adjust
> >the phase of the signals being picked up by the vertical feeds so that
they
> >differ by 180 degrees.(in some direction)
>
> > > ... do I assume rightly that the
> > > COS lengths recommended do NOT include the
> > > 15 to 20 meter sloping termination lengths at
> > > each end?
>
> And the only thing achieved by the sloping termination is avoiding the
> necessity of using a separate guy wire to hold up the pole where the wire
is
> terminated. You have the same vertical antenna component whether the wire
> is sloped down gradually over a 15-20m. length or whether it is terminated
> immediately with a vertical wire.
>
> Don K4KYV
>
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