Gary, Maybe not a split rail but I have plans for a three rail vinyl
fence in front of the house and it will pass near the barn where my
multi-channel remote control coaxial antenna relays are located. The
plan it to put electric fence wire between the decorative rails to
discourage stock from pushing the fence over. I exclude the herd from
this particular pasture from spring greenup time till well after the
grass recofvers from (typically) July haying. Maybe I can dual purpose
the wire and share it so that it can be switched into Beverage mode or
electric fence mode. Then the question becomes: is it OK to have dual
parallel conductors vertically stacked with a couple feet of separation
for a Beverage antenna?
If I use only one of the wires as an antenna, then what? Would the
choice of best wire be made based on knowledge and theory or try and
see? Decision decisions... I guess I will have to bite the bullet
and load up the antenna modeling program that came with the ARRL antenna
handbook (I think,)
Patrick NJ5G
On 2/3/2015 1:17 PM, Gary - AB9M wrote:
Patrick,
It'd be much better if you could replace the barbed wire fence with a
split rail or other non-conductive material fence. I once stapled hook
up wire along the top rail of a split rail fence running on three
sides of my acre lot ( two sides 120' x one side 240'). Running a
single wire to the shack and Dentron 160 - AT Transmatch, I used a
noise bridge to set the output impedance for the AUX Antenna jack of
my Corsair-II to 50 Ohms on 80 & 75 meters. The low wire may not have
been a true Beverage, but it was a very low noise antenna which
allowed me to work 4X on SSB at my Sunset. I received a couple
skeptical on the air comments from others who couldn't even hear the
Israel end, but I have the QSLs.
ON4UN's Low Band DXing book or the ARRL Antenna Handbook, provide the
the theory; try to NOT deviate too far in your application, unless you
want the results to deviate far too much from your expectations.
73 & DX,
Gary - AB9M
-----Original Message----- From: Patrick Greenlee
Sent: Tuesday, February 03, 2015 7:39 AM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Beverage Antenna
Chuck, A very good point.
That is the essence of my interest in the effect of having some parallel
grounded conductors (5 strand barbed wire fence with steel posts) a
short (TBD) distance below the beverage antenna. I'm curious to know if
the fence would act similar to good conductivity dirt WRT Beverage
performance.
If not, then what if the antenna wire were mounted above 3 parallel but
horizontally spaced conductors looking for the beginnings of the effect
that would be achieved theoretically with our old friend the infinite
conductive plane over which we mount our verticals? Why 3? Because it
would be easy to put a strand of wire on either side of the top strand
of barbed wire using readily available inexpensive plastic insulating
arms made expressly for adding electric fence wire to a fence built with
T-posts. With a little more fussing I could attach 2 wires either side
of the center wire giving a better approximation of the infinite plane.
One of our experts can maybe tell me if the parallel grounded wires
need to be tied together laterally or if that would matter.
Patrick NJ5G
On 2/3/2015 7:00 AM, Chuck Dietz wrote:
Part of the problem with comparisons of low band receiving antennas
made in
various locations is that the composition of the ground under the
antenna
makes a huge difference.
Chuck W5PR
On Mon, Feb 2, 2015 at 8:22 PM, Roger (K8RI) on TT
<K8RI-on-TowerTalk@tm.net
wrote:
That's why I have the HB and Antenna HB on the same machine as the
mail.
Items, topics, and components are so much easier and faster to find
than
with hard print. Less than 10 keystrokes to find nearly any
specifics on a
topic. Course as some of my answers have shown, I'm too lazy to always
double check!
I can't say the computer is smaller, lighter, or cheaper at 60#, 23"H X
7.5"W X 20" D, running 8 64 bit cores/CPUs @ 4.1 GHz, & 16 GB of
RAM and
cost less than half our first color TV. OTOH the Internet has been
a POS
this past week, so I'm glad I had most of the data here. Still, with
posted links on mans news groups, they came up invalid (err 404)
even from
news sites and some ham pages were taking so long to load they timed
out.
I don't think I was getting more than a fraction of the 100 Mbs
service I
pay for.
Speaking of "pay for" and I think this is relevant to hams who
depend on
electricity... My electric use in the shop has been down this past
year and
on the equalized billing plan It almost doubled last month (with
less use)
I think I smell a rate increase a coming.
73
Roger (K8RI)
On 2/2/2015 2:14 PM, Jim Brown wrote:
On Mon,2/2/2015 10:05 AM, Don wrote:
First, I'm surprised there does not seem to be any published
measurements taken at a common test site of a Beverage at various
heights
and lengths (such as done with yagi's, and other antennas on test
ranges).
Why do you assume that nothing like this exists? Beverages have been
around for nearly a century, and it is quite likely that there's a
lot of
published work that you haven't looked for in scientific journals.
It's
also possible to model antennas like this and do your own study.
There's a
lot about Beverages (and other RX antennas) in the ON4UN book, and
in the
ARRL Antenna Book.
Email reflectors like this one should not be a substitute for
pulling out
the books and studying them. Many of us who post answers to
questions like
this have done that study, or done that modeling, or built those
antennas,
and are sharing what we've learned. As VE7RF has noted, optimum
height is a
function of wavelength. When a Beverage is higher than that, it
doesn't
stop working, like throwing a switch, it just becomes less
effective. My
550 ft Beverages, a full wavelength on 160M, at an average height
of 5-6
ft, are quite effective on 40M, and are still working on 20M! How do I
know? I run diversity with my K3 using the TX dipole at 125 ft into
the
main RX and the Beverage into the second RX.
73, Jim K9YC
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73
Roger (K8RI)
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