Don't overlook 6061T6 aluminum - 2" OD with .25 or .375 wall thickness.
Lightweight (relatively), no, you can't put a monoband 40m beam 10 feet above a
thrust bearing but within the specs, it works very well. No rust, clamps well
to prevent slipping, exactly 2" OD so it fits well. Great for VHF and smaller
HF antennas. I had a pair of 36 foot long 6m antennas on one for many years in
Ohio, one was 22 feet out the top of the tower, it survived 60+ mph winds, it
bent in the wind but sprung back. Last I know these were less than $200 for a
24 foot long section. No comparason to the chrome molly masts for strength but
probably 1/4 to 1/3 the weight.
Terry
----- Original Message -----
From: "jimlux" <jimlux@earthlink.net>
To: "k2vi" <k2vi@cox.net>
Cc: TowerTalk@contesting.com
Sent: Wednesday, February 25, 2009 11:53:18 PM GMT -05:00 US/Canada Eastern
Subject: Re: [TowerTalk] Mast material
k2vi wrote:
> Hey guys, can someone please advise me on the mast to use, I was
> looking at 2" EMT pipe I saw in the electrical dept at home depot.
> Keep in mind this pipe will be supporting a hy-gain 203BA which has a
> 16' boom and weighs 32# also it will be pushed up from the thrust
> bearing about 6'. Im sure it will be fine here in va beach. Right now
> im using a galvinized 2" shedule 40 pipe that weighs a ton.
>
EMT is pretty thin wall, and structurally not all that hot. After all,
it's really only designed to protect wires from abrasion. For instance,
you can't use it to support an electrical box holding a duplex
receptacle sticking out of the ground.
I've built structures from EMT (like a big geodesic ball), and it tends
to split along the weld, for instance.
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