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Re: Topband: beverage lobes

To: Tom Rauch <w8ji@contesting.com>, topband@contesting.com
Subject: Re: Topband: beverage lobes
From: Larry Molitor <w7iuv@yahoo.com>
Date: Tue, 9 Jan 2007 09:13:06 -0800 (PST)
List-post: <mailto:topband@contesting.com>
Tom Rauch <w8ji@contesting.com> wrote:
Since I haven't been in Washington and operated weeks and 
weeks watching antennas, Likewise I have never operated Topband from the 
eastern seaboard. (But I have several good friends who do) However, when I 
moved from central AZ to central WA, Topband conditions were so very different 
that I thought I must have moved into some kind of space/time warp where the 
basic laws of physics were different!

Besides the issue of dirt, the issue of physical placement on the face of our 
planet seems to be important. I'm certainly not an expert in these matters but 
let me throw out a few possibilities.

For one thing, it's farther from me to ALL the population centers with 160 
activity by a couple of hops than from the east coast USA. More hops generally 
means lower arrival angles. (but not always!)  Lower arrival angles would have 
an impact on the  perceived performance of various RX antennas.

Besides distance, the GCB (great circle bearing) to most 160 activity is 
through the auroral influence zone for me. W1AW is 80°, through the edge of the 
aurora.  Many nights, even with a good Beverage on them, I cannot hear W1AW! 
All of Africa is on the other side of the auroral zone from me! Europe is 
through the very center of the auroral oval. Does this have any effect on the 
perceived performance of various RX antennas? If so, how, why? 

How about localized anomalies? N7UA is about 150 miles west of me. N6TR is 
about 150 miles SW of me. W7LR is about 250 miles east of me. Conditions 
reported by these stations are almost always significantly different than what 
I observe. Both openings to various locations and azimuthal arrival angles of 
received DX stations are different. Usually, but not always. What's this all 
about? Spotlight effect? Maybe, maybe not. In any case this would surely effect 
the observed performance of RX antennas.

Regarding the phased systems, based on the limited testing I've done I would 
expect that a pair of broadside 800 footers would indeed outperform a single 
1100 footer. However two local practical considerations far outweigh the 
theoretical improvement. 

The termination grounds are a real problem for me. Each one requires as much 
work as stringing out 1100 feet of wire. When it's time to farm, the ground 
rods have to be pulled up, and it's not always easy to pull them up out of the 
rock. I frequently need to use the hydraulics on the tractor to get them out. A 
single 1100 footer has two grounds. A pair of 800 footers has four! Not good!

Single wires can be routed like spokes in a wheel with the feed point grounds 
close to each other. The feedlines to the switch box are short and can be kept 
out of harms way. A phased pair needs to be separated by a very large distance 
requiring the feedlines to be stretched out over a wide area. Between large 
animals stepping on them, small animals eating them, and farm equipment running 
over them, it has proven impossible to maintain such a system. I would love to 
do more work with phased systems but it's just not gonna happen with the 
conditions I presently have to work under.

BTW, this morning close to my sunrise, I was hearing R1FJT on an EWE pointed to 
45°. Go figure......

73, 

Larry - W7IUV
DN07dg - central WA
http://w7iuv.com





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