In a message dated 97-03-04 15:17:02 EST, firstname.lastname@example.org (Werner H. Berli)
> What is the expected force F at the top of the mast?
> What is the expected moment Mb at the base B of the mast?
> Can anybody give me or point me to the proper equations? (metric or
> nonmetric units ok)
Here's a couple of ways to do it.
The original landmark article by Stan Griffiths, W7NI, that appeared in
the National Contest Journal several years ago is available from TOWER TECH.
Give me your address and I'll send you a copy. Anyone in the US who would
like one please send an SASE to TOWER TECH, Box 572, Woodinville, WA, 98072
for a free copy.
Second, a very good discussion is in Dave Leeson, W6NL, ex-W6QHS's book,
"Physical Design Of Yagi Antennas" published by the ARRL.
Third, TOWER TECH is almost ready to make available the MARC program.
It stands for Mast, Antenna and Rotator Calculator. It will allow you to
have up to six antennas on a mast and will calculate the bending moment based
on your input. At this time it is only in US units and not metric. It will
be $9.95 and will allow you to experiment with different loads and windspeeds
for any antenna mast system. The program will even recommend suitable
rotators based on the Effective Moment of the antenna load.
73, Steve K7LXC
TOWER TECH -- professional tower supplies and services for amateurs
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