I passed along this info to Dean Straw, N6BV, the ARRL Antenna Book
editor. He replied that since the 19th Edition, he's used EZNEC/4 (an
NEC-4 based program) for generating rhombic and vee beam data. I'd hope
that it would agree closely with the 1980 NEC analysis.
Roy Lewallen, W7EL
Crazy George wrote:
Scott:
The curves for V Beams in the ARRL Antenna Handbook, and apparently also in
the engineering texts were derived from a few experimentally determined data
points assuming a sinusoidal current on the arms. In the July 1980 IEEE
Transactions on Antennas and Propagation, Gary Thiele and Ernie Ekelman
published a rigorous NEC analysis of the configuration, including a couple
of useful curves. Both the optimum included angle vs. arm length and
directivity vs. arm length differ significantly from the previously
published curves. So, dig up a copy of IEEE-A&P Trans., Vol. AP-28, No. 4,
and look on pp. 588-590 for the full story.
--
Crazy George
Remove NO and SPAM from return address
|