[TowerTalk] 2" OD Long Masts

[Marsh Stewart]

I'd recommend considering chrome molly steel, 1/4" wall, galvanized and
rated at least 100,000 psi mast yield strength. A 22-foot mast like that
weighs about 125 pounds. Then run the calculations for the antennas you want
to stack using their wind load areas, heights above the top of the tower,
and your wind speed.

AntennaMast.xls available on the web for download is easy to use.

Marsh, KA5M



-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of Byron
Tatum
Sent: Tuesday, August 26, 2014 8:23 AM
To: TowerTalk at contesting.com
Subject: [TowerTalk] 2" OD Long Masts

Hello-
  For years I have used the 2" OD, 6061-T6, 1/4" wall x 24' long aluminum
masts to stack VHF and UHF antennas. I have seen these take a bend a time or
two over the decades.
  I wanted to ask:
    1. If I was to switch to 2" OD steel, as a mast to extend about 15'-18'
out the tower top for stacking VHF/UHF long boom yagis, what would be a
suitable grade of steel, the finish and wall thickness?
    2. I have heard of inserting a smaller aluminum tube inside the 2"
aluminum mast, in the area where the mast exits the tower top and on above a
bit. I wanted to ask if someone here has experience with inserting an
aluminum tube inside the 2" OD mast? I would assume it would be 1-1/2" OD,
of similar material and length and what wall thickness?
  I guess reasons I have stayed with the aluminum masts is that they are
lightweight and easy to handle, plus no rusting down in this Gulf Coast
area.
     Thanks, Byron WA5THJ  
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