I came across an intriguing antenna paper at http://www.dlr.com/Nabpaper.htm
and thought it might be of interest to Top Banders. An abstract, taken from
the
Web page, is given below.
AN EFFICIENCY COMPARISON: AM/MEDIUM WAVE
SERIES-FED VS. SKIRT-FED RADIATORS
ABSTRACT
This paper will address a comparison of the radiating efficiency of a
single AM/Medium Wave mast configured as a base insulated radiator and as a
skirt-fed
("folded monopole") grounded radiator each with three ground system
configurations, including a standard 120-radial copper wire system, a
30-radial copper
wire system and a single copper ground rod. Measured results for two tower
electrical heights of 98.3 degrees and 61.5 degrees for both the base
insulated
and the folded monopole cases will be presented. Each radiator
configuration will be analyzed using method of moments computer modeling.
These analytical
results will be compared with actual field strength measurement results
accompanied with the associated ground radial current distribution
measurements. The
relative merits of the series-fed versus skirt-fed AM radiators and the
associated ground system options for each will be discussed with definitive
modeling and
test results to substantiate any conclusions that will be presented. All
experimental tests were conducted at the new expanded band frequency of
1680 Khz with
a transmitter power of 400 watts.
73, John W1FV
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