I've heard people talk about cutting out braces on the tower.
I say DON'T DO IT. You shouldn't cut the tower because that goes through the
galvanizing and exposes the steel and could potentially be a place where
rust starts.
If you use a long gin pole, you can raise it out the top. Pete, N4ZR made
another good suggestion using a basketball hoop to keep the mast from
flipping ends with a short gin pole. You can also attach a weight to the
bottom of the mast to help balance it. Unfortunately the weight has to be
enough to keep the mast from flipping over. That can be a lot of weight.
That's how I put the first 21 foot pipe mast up. Boy was it heavy but it
worked. Now that I have the long gin pole, it's much easier. I also prefer
using aluminum masts over steel masts for several reasons. One, the aluminum
mast is much lighter for the same strength. Two, boom to mast clamps bite
into aluminum more easily than steel and will tend to slip less in the wind.
Chrome moly steel masts sure are strong but they're slippery. They're also
very heavy. A 3" x 24' chrome moly mast weights over 200 lbs. My 3" x 24'
aluminum mast (3/8" wall) weighs only 96 lbs. Sure, the compression bending
strength of the aluminum is less (38,000 lbs/ sq in versus 100,000 plus for
the chrome moly) but the aluminum comes close given the much thicker wall.
My big antennas (M2 20M5 and 40M4LLDD) aren't very high above the thrust
bearing anyway. The antennas up on top are an M2 6M7, an M2 2M18, and a
homebrew 16 element K1FO design 222 yagi. The 3" aluminum masts have
survived some very major wind storms here.
If you can't get the mast up and out, leave it in the tower until you take
the tower down.
Jerry
-----Original Message-----
From: K7LXC@aol.com
Sent: Friday, April 19, 2013 6:26 PM
To: towertalk@contesting.com
Subject: [TowerTalk] Mast vs. R45G part deux
Howdy, TowerTalkians --
Tnx for your inputs but I think I need to describe what I want to do
in more detail.
There is a heavy 20' mast sticking out of the top of a pointy top 45G.
What I want to know is if by lowering the mast down thru the middle of the
tower, if at some point you can exit the mast thru the face of a tower
section? I haven't tried it and doubt if it could be done but I wanted to
see
if someone in the group has done it or attempted it. Tnx.
Cheers,
Steve K7LXC
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