>
>The new numbers could have some serious implications for some of us. Let's
>translate this discussion into English for the non-engineers among us.
>
>Obviously, the new computation standards have significantly increased the
>published windload ratings on some Hy-gain antennas. For example, the TH-7
>was previously rated at 9.4 sq. ft., but is now rated at 11.5 sq. ft. That's
>better than a 22% increase. The question was asked before, but not answered,
>so I'll ask it again: Have the new computation standards also increased the
>windload handling capacity of popular Amateur tower configurations, or have
>many of us overloaded our towers by relying on the old formulas?
I think this just goes to show that there are many ways to calculate "square
foot" capability when it comes to antennas and/or towers. Both tower and
antenna manufacturers have been (intentionally, I believe) vague about how
they arrive at their "square foot" numbers. We hams naively assume all
square foot numbers are based on the same standard calculation method and
the antenna and tower folks don't do much to help . . . until now!
Thank you, Roger Cox. You have taken a giant and bold step toward helping
us understand this very important piece of the picture. We now have a MUCH
better idea of how at least one major antenna company (HyGain) calculates
the windload numbers they publish. Now if Force 12, M Squared, Cuschcraft,
Moseley, and the rest would just follow suit, think of how much better of we
would be!!
Attention Antenna Buyers:
You are the guys who can make these other companies come forth with better
and more clear information on the true wind loading of their antennas.
Simply tell them you want to know the projected areas of the elements and
the boom as two separate numbers without any correction factors for the
shape of the materials they are made of, just like HyGain does. This will
finally allow you to compare antenna windloads between different models from
different manufacturers. Without this, we are back to guessing . . . On
second thought, don't ASK for that information, INSIST on it. After all,
you ARE the customer and its YOUR money you are spending.
The only other thing I could ask for is a sheet showing the SPECIFIC
measurements and subsequent calculations for each commercial antenna model
so I will fully understand how the numbers were determined. Why would
anyone want to keep that information a secret (unless it really isn't
correct)? With this information fully revealed, it would allow a homebrewer
to calculate the windloading of his homebrew array in the same manner as the
commercial guys do it.
Then the only things left to do are make sure the tower manufacturers are
doing their calculations in a standard way and figure out how they (the
tower manufacturers) relate their numbers to the antenna manufacturers numbers.
I think we are on a roll here and I encourage everyone of you to help (with
your buying power) to bring us to a new level of awareness regarding antenna
and tower windloading. There are enough of us here to make a difference,
but only if we pull together, believe me!
Stan w7ni@teleport.com
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