BUDDIPOLE IN THE FIELD
BUDDIPOLE IN THE FIELD
BUDDIPOLE IN THE FIELD
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details, including the important comparison to the isotropic radiator, can<br />
be found in the elevation plot in Figure 11.<br />
Figure 11 Elevation plot for a Buddipole on 10m at 8 feet<br />
The outer ring on this plot is 5.88<br />
dBi. But, this plot looks<br />
significantly different than the one<br />
for the 80m dipole at 130 feet.<br />
Most of the radiation is directed<br />
up towards the zenith. Power<br />
levels below 45 degrees from the<br />
horizon taper off quickly. At 20<br />
degrees (approximately) the<br />
power is 5 dB below the peak. At<br />
15 degrees power is 10 dB below<br />
the peak. At 10 degrees we are 15<br />
to 20 dB below the peak.<br />
Near Vertical Incident Skywave<br />
(NVIS) antennas do<br />
intentionally radiate towards the<br />
zenith. They are popular<br />
antennas for HF close-in<br />
communication. But, they use<br />
the 80m and 40m bands for this<br />
activity, not 20m or above, as<br />
the ionosphere does not reflect<br />
higher frequency signals well at<br />
high angles. The Buddipole<br />
makes an excellent NVIS<br />
antenna on those lower bands.<br />
Consider the area of the plot 15 to<br />
20 degrees either side of the<br />
zenith as illustrated in Figure 12. This area is highlighted as a shaded<br />
triangle.<br />
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