To All:I apologize for not providing the reference to the Dick Weber K5IU
article on the subject of shortened elevated radials.
Here are the references:
"Optimal Elevated Radial Vertical Antennas" by Dick Weber, K5IU. COMMUNICATIONS
QUARTERLY, Spring 1997, pp 9-27.
"Modifying a 160 Meter Elevated Radial Vertical" by Duane Walker, KE7BT,
COMMUNICATIONS QUARTERLY, Summer, 1998, pp 19-28.
Also, Les Moxon, G6XN wrote about this topic in Chapter 4, pp 43-45, of his
very useful book, "HF Antennas for All Locations." (RSGB 1982)
In summary, 1/4 wave radials may not be the optimal arrangement for your
particular antenna system depending upon many factors. Dick Weber's work
suggests that for shortened radials, 60 degree radials (approximately 67% the
length of a 1/4 wavelwength) is an optimum length. Shorter than that and
efficiency drops and bandwidth narrows significantly.
Measuring your radial currents with either an MFJ current meter or a homebuilt
test set is a good way to check your radial currents. Incidentally, using a
current meter on your ground radials is also worthwhile to check their
effectiveness.
If any one wants a copy of the above Communications Quarterly articles, I will
be happy to email them to you.
73, Dennis W0JXMilan, OH
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