Hi Steve,
You wrote:
> I think that you forgot to multiply by the wind pressure. At 70.7 MPH,
it's 20 psf, 80 > MPH is about 25 psf. Your analysis doesn't allow for the
load
> distribution up the mast. (Sorry, I'm not an engineer.)
I wrote:
>> Antenna area (sq ft) load (#) (@ 80mph
using 25#/sq ft)
>> TH7 9.4 235
>> Disc1 (40m 1 el) 2.7 68
>> 214FM (2m 14el) 1.7 43
>> WARC 2/2 (12/17m yagi) 3.1 78
>> mast .1/ft 2.5/ft
As you can see Steve, I did multiply by the wind pressure (25 psf).
My distribution again was:
> Antenna area (sq ft) Hgt above tower(ft) bending moment
(ft#)
> TH7 9.4 .5
118
> WARC 2/2 3.1 5 390
> Disc1 2.7 10
270
> 214FM 1.7 12
516
> mast 1.2 6 (avg)
180
Note that bending moment is calculated from areaXwind pressureXHgt above
tower. So I did allow for load distribution up the mast.
The load WILL be supported. Try the MARC program (I don't have it) with the
antenna distribution I posted and let me know the results. Placing the high
area antennas close to the tower makes a big difference.
73, Ed
Ed Jensen, K5ED, El Paso, TX, k5ed@dzn.com
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