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Re: Topband: beverage lobes

To: <k2xx@swva.net>
Subject: Re: Topband: beverage lobes
From: "Tom Rauch" <w8ji@contesting.com>
Reply-to: Tom Rauch <w8ji@contesting.com>
Date: Tue, 9 Jan 2007 14:45:04 -0500
List-post: <mailto:topband@contesting.com>
> When observers are making judgments on arrival angles, are 
> they basing their judgments on which of several different 
> types of antennas with different TOAs produces the loudest 
> received signal?

I only do that on transmitting antennas, and I never base my 
opinions on a single weekend once a year during a contest. 
With station after station coming at you that just isn't the 
place to form accurate opinions.

So far as transmitting antennas, nearly 100% of the time my 
~200 foot omni vertical with 100  200-foot radials beats a 
dipole at 300 feet. It was this way in 1970 in Ohio, in 2000 
and 2001 here in GA, and it is that way at the solar 
minimum. These are all blind A-B tests, the person giving 
the report has no idea what antenna I am using. This leads 
me to believe the wave angle is pretty low, or any path in 
any direction from here (or Ohio) favors a vertical. By the 
way a dipole at 130 feet is often insignificantly behind the 
high dipole, and a 1/4 wl vertical with 50 radials is 
insignificantly behind my 200 foot vertical. The primary 
exceptions are during geomagnetic storms or right at 
sunrise/sunset.

So far as receiving, I only consider readability of the 
weakest signals. Nothing else. All of my antennas are gain 
equalized so they all have about the same nighttime noise 
floor. Since I normally receive in stereo with matched 
receivers and can pick any antenna on any ear it is easy to 
get a feel for the best overall copy. I care less if someone 
already 20 dB out of the noise is 10 dB weaker or stronger.

All of my nighttime noise is propagated noise. The 
propagated noise is typically ten dB or more greater than 
local daytime noise, so local noise is not a factor at my 
location.

I really don't know how we would measure arrival angle on 
160 without an interferometer setup for nulling signals. 
Quite often there is considerable multipath or multi-angle 
propagation, I do know that from actual measurements.

73 Tom 


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