VE6WA wrote:
>C31XR: 10.7 SF
Mag240N: 6.8 SF
16 ft Mast: 1.6 SF for 2 inch or 2.4 SF for 3 inch
Rotator: 1 SF (approx)
>Total load: 20 to 21 SF
>Still deciding on height, but the desire is for either 80/87 feet or 90/97
feet. In either case in a 100 MPH environment, this load exceeds the
capacity of 45G and 55G.
FWIW I had a 5 el KLM 20m stacked 7' over a
3 el KLM 40m at 155/148' in Colorado that was up
~11 years. We routinely had >100 MPH Chinook winds
(you should be familiar with those if you lived on
the Eastern slope in Alberta) each winter and once
had two >140 MPH (measured at NOAA in Boulder). One
of the >140 MPH toppled a chimney into my living
room and did $20k worth of damage (in 1982 dollars).
148' of Rohn 45G was guyed 5 times with 1/4" EHS
on the top set and 3/16" EHS on the bottom 4 sets.
I never had any problems with tower damage although
the rearward elements did take a slight set over time
due to normally being parked pointing away from the
prevailing Chinook direction (West) which is easiest
on the rotator (never a problem with a KLM-1500HD).
You can derate the above wind speeds by about
15% due to relatively thin air at 5000' elevation. IMHO
Rohn specs are very conservative, but if you are truly
paranoid, do as K7LXC recommends and follow their
recommendations.
73, Bill W4ZV
P.S. I used 2" Chrome-Moly mast rated ~140k PSI.
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