Topband: beverage lobes

[David Gilbert]

Tom Rauch wrote:
> 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.

That's quite interesting.  Bob Brown, NM7M, once told me that for my 
location (southern Arizona near the Mexican border) vertical 
polarization had an 11 (eleven!) db advantage versus horizontal 
polarization for DX paths on 160m.  He very briefly describes the 
reasons for that in one of his propagation tutorials, but I'd like to 
better understand the theory behind it someday.  In any case, your 
observations on the significant advantage of the tall vertical versus 
the high dipole, and the relatively minor difference between the tall 
and short verticals, would seem to align with Bob's statement.

Dave   AB7E




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