|Subject:||Re: [TowerTalk] Weight of mast material|
|From:||Mahlon Haunschild <firstname.lastname@example.org>|
|Date:||Tue, 20 Jan 2004 21:41:08 -0600|
I don't know about the mast per se, but your overall plan concerns me.|
Assuming that the 40m antenna you are talking about is the Cushcraft XM240, a little math shows:
Weight Wind area (sq ft) mast 90 2 (est.) C31XR 82 10.7 XM240 55 5.5
totals 227 18.2
Rohn 25G is only rated for 8 sq ft at 70 ft. & 110 mph per their drawings (you are in 105 mph land, per EIA/TIA 222, so you need to design for that). Also, 227 lbs rotating weight is a LOT for the 25G structure to withstand. How will you control the torque caused by the antenna stopping & windmilling?
If you're married to the idea of a 70 ft 25G tower, one thing you should do is get an aluminum alloy mast. Cuts down the weight dramatically. Another thing to do would be to not use a 40m beam.
Mahlon - K4OQ
Julio Peralta wrote:
Thanks to all who replied RE: the weight of Chromolly. I think it would be safe to figure it a about 90#.
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions and ask for Sherman, W2FLA.
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