I once had a 550-foot Beverage in the dirction of Europe. It was about
equal to my phased verticals in that direction on 160m, and worked even
better on 80m and 40m. I remember during CW contests on 40m that the
Beverage was more directional than my 2-el Yagi and was a definite asset
in reducing QRM from JA when working EU. The Beverage was about 4
wavelengths long on 40m and in spite of the fact that a Beverage starts
losing gain after it is more than 2 wavelengths long, it still appears to
be come more directional.
Personally, I don't feel that exact multiples of 1/2 wave has anything to
do with how well a Beverage performs. After all, it's a non-resonant
antenna, isn't it?
The reasons that a short Beverage (560 feet) might not display much F/B
on the AM BC band is that it is even shorter there (in terms of
wavelength), particularly if you're closer to 550 kHz than 1600 kHz.
Using multiple radials might be another reason. I always used only one
radial on my Beverages, and at only the terminated end. That radial ran
in the same direction as the desired incoming signals. The F/B and F/S
was always good.
73, de Earl, K6SE
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