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ANTENNAS FOR 100 POUND DXPEDITIONS The far-field plot for this antenna appears below. Note that the elevation plot shows a much lower take off angle for the vertical dipole when compared to that of the vertical monopole. The outer ring represents 0.76 dBi in these plots. The monopole had an outer ring value of 0.33 dBi. Elevating the feed point and radiator lowered the take-off angle and increased gain slightly.

Half-wave vertical dipole on 10m

Half-wave vertical dipole on 10m

Figure 25 Half-wave vertical dipole on 10m over good ground Below are the plots for poor ground. Note that the outer ring represents 0.61 dBi in these plots over poorer ground, 0.1 dB down from the good ground plot, but far less of a degradation than that observed when we moved a quarter wave monopole from good ground to poor ground. Except for a slight reduction in overall gain, the antenna performed about as well over poor ground as it did over good ground. This is most likely due to getting the feed point of the antenna well away from the lossy ground. Half wave vertical dipole (HWVD) antennas are a fine choice for 100 Pound DXpeditions because they are relatively easy to erect, have a small footprint, and are relatively immune to the poor sandy ground of islands and beaches (places attractive for our lightweight DXpeditions). A 40m antenna is unwieldy at 66 to 70 feet, but antennas for bands 10-15m are very practical, light, and easy to deploy.

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Antennas for 100 Pound DXpeditions - volume 1  

Computer-based antenna modeling and direct experience with lightweight portable antenna systems. Volume 1: Selected high band antennas [20-6...

Antennas for 100 Pound DXpeditions - volume 1  

Computer-based antenna modeling and direct experience with lightweight portable antenna systems. Volume 1: Selected high band antennas [20-6...

Profile for ne1rd
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