[TowerTalk] Mast pipe load calculator
k9zo at hotmail.com
Wed Feb 5 22:00:52 EST 2014
I found a really good mast pipe load calculator on the DX Engineering web site. www.dxengineering.com
They advertise a 22 ft X 2 inch pipe (also stock a 3" one) which seems about perfect for my next upgrade. I made up a situation based on antennas that I have around just to see how it worked. I put the mast 18 ft above the TB3 bearing, and 4 ft below so the rotor could be down a bit from the top. Then I placed a 205CA (9 sq ft) half a foot above the bearing. Then I placed a 155CA (5.2 sq ft) 6 feet above the bearing. Then I put a 105CA (3.9 sq ft) 12ft above the bearing. Finally I put a 6M7JHV (2.5 sq ft) at the very top just to see what would happen. For me, these are pretty realistic antennas.
The program has a good diagram and lets you fill in the names of the antennas and spacing so you can actually visualize your plan. Then you hit "Calculate" and get the result. In my example, the configuration passed 60 mph, and 80 mph, but failed at 100 mph. This is a great starting point! So I have to downsize a bit. We get fierce winds and the antennas get covered in ice a couple times in the winter. I really don't like stacking so many antennas because it's nearly impossible to do any maintenance without taking everything down. This is so much more scientific that getting a Rohn mast and welding some water pipe inside to beef it up a bit. It's fun to play with, but it took me a while because I just had to browse throug all the towers and associated hardware.
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