Rohn 25G without guys, how high?
On Mon, 2 Jul 2007 19:52:24 -0500, "J. Mc Laughlin"
wrote:
Dear Rick: Sorry to have received the call-sign incorrectly. Your
Father's call does not ring any bells.
The main reason for two sections above a house bracket is because of the
significantly greater probability of greater wind pressure on the two
sections compared to three sections that start at ground level. You also
expect to have more effective area for the greater wind pressure to work on.
I have become convinced that the reason few urban TV/FM antennas and
Rohn 20 (no cross braces) towers fail is because of a dramatic reduction in
wind pressure up to about 35 feet above ground in a typical urban
environment.
The real limitation (for you) may turn out to be due to the building
code used in your area. When the time comes to have a serious antenna tower
for HF, do find a professional engineer licensed in your State who's advice
about how to satisfy the building code and 222G will be worth every penny
you pay to him or her.
Warm regards, Mac N8TT
P.S. My neighbor K8DO still does things that give me the willies. Even
when I was young, I sure would not climb 50 feet of un-guyed Rohn 25.
Medical school instills rather more "confidence" than engineering schools
do.
Shucks, I met him way before he became so conservative.
|