Hardy:
What you say is perfectly true, but only for a particular case.
A lot of texts say that because that's what appeared in Beverage's original
AIEE paper. Beverage was concerned only with LF signals that were being
received only by groundwave. In that case, perfect ground would yield no
induced signal. He never addressed the case of skywave propagation in the
professional journals.
(Later, Beverage wrote a paper in QST about his antenna for 200 meter
reception and wrote about very good results with stations all around the
country via skywave.)
I'll also appeal to basic principles here. All the Beverage can receive is a
horizontal vector in the incoming wavefront - in other words it relies on
the incoming wavefront not being perpendicular to ground. How that is
produced does not matter; it can be "feet dragging" due to lossy earth or
tilt due to arrival angle of an ionospherically propagated signal.
Chuck
----- Original Message -----
From: "Hardy Landskov" <n7rt@cox.net>
To: "Roger D Johnson" <n1rj@adelphia.net>; "Tom Rauch" <w8ji@contesting.com>
Cc: <topband@contesting.com>; "Ford Peterson" <ford@cmgate.com>
Sent: Saturday, August 21, 2004 7:34 AM
Subject: Re: Topband: Two Wire Beverage Query...
> All,
> When I took a graduate course in antennas, we studied the Beverage. The
> lossy ground is what makes it work by tilting the electric field vector
> between the wire and ground. That creates an E-field component in the
> direction of the Beverage wire. If the ground were perfect, no tilting
> occurs and you would have a terminated transmissin line over ground which
> will receive nothing.
> I agree with your first sentence but not the second. I will have to agree
> with Tom.
> If you really want to make a Beverage "quiet" then it seems to me that you
> would need a ground screen several feet wide beneath the Beverage wire. I
> don't think a single wire will do the job. The wire will still see a lot
of
> the surrounding soil. A single wire would have to be within a few inches
of
> the Beverage wire to do the job.
> Regards,
> Hardy, N7RT
>
> At 12:46 PM 8/20/04 -0400, Roger D Johnson wrote:
> >Tom Rauch wrote:
> >
> >> Second, if it did work to crate a low resistance path the
> >> effect would only be to make the antenna stop working.
> >> Beverages depend on ground losses to function.
> >
> >I respectfully beg to differ. The original Beverage was developed
> >to receive LF and VLF signals via groundwave. The lossy ground
> >caused the wave to "tilt" and hence it was able to induce a signal
> >into the horizontal Beverage wire. The situation on HF is different
> >as the ionosphere supplies the wave tilt in most cases. It might
> >actually be an advantage to make the antenna "deaf" to groundwave
> >signals in those cases where there is a strong local broadcast
> >station.
> >
> >My understanding of the wire under the beverage was that it stabilizes
> >the impedance when the ground conductivity changes (after rain for
> >instance). A stable impedance makes for stable nulls.
> >
> >73, Roger
> >
> >--
> >Remember the USS Liberty (AGTR-5)
> >http://ussliberty.org/
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> >
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