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[TowerTalk] Adivce Using Irrigation Pipe

To: "Tower and HF antenna construction topics." <towertalk@contesting.com>
Subject: [TowerTalk] Adivce Using Irrigation Pipe
From: Phil Chambley <pchambley@gmail.com>
Date: Fri, 30 Apr 2010 13:46:40 -0600
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
I'm looking for advice on an antenna system I'm planning on putting up this
summer.

While I'd love to have the tree height here to hang a couple of pairs of
Bobtail Curtains, where I'm at near Helena the pines just don't get the
water to get the height required. I've been reading back though the archives
and gleamed some very good information on using irrigation pipe as
verticals.
What I am planning for 75 is a four square, last summer I cleared some trees
and set some 4x4's in concrete for the bases. I'm planning on using 3 inch
irrigation aluminum with one 40 foot and a 24 foot piece put together with a
18 inch or so sleeve of the pipe split enough to allow it to fit inside the
other 2 pieces.

For the bases on the verticals I'll take a piece of 3 inch PVC to slide over
the aluminum and slide reducer bushings into the PVC, drill a hole through
the bushings for the pivot point in a base built like N6RK shows on his
website (really nice Information, thanks Rick) to lift it with another 30 or
40 foot piece of pipe for this purpose. The 4x4's are sticking up about 5
feet so I can attach the verticals at this point in addition to the guys.

Because I have about 10 inches of soil on top of solid sedimentary rock, I
think I just use 1 inch round steel rod driven into the ground a couple of
feet as guy anchors. As for the guy points on the verticals, I saw where
someone had slipped a piece of 3 inch PVC pipe over the tubing and glued a
plastic toilet flange on the PVC and held the PVC in place with a few
screws, i thought that was a really good idea too. I don't know how many guy
points 2 or 3 would be enough and where on the verticals I should place the
guys. It will occasionally have to stand up to 70 mph winds or more but it's
in a location where it can't hurt anything if it falls.

I thought about using a 40 foot 3 inch and then a 2 inch piece on top with a
2 inch PVC pipe slipped over with 2 inch couplings on the PVC pipe ends and
turn those until they just fit inside the 3 inch pipe. Not having access to
a lathe I figured I'd just go with the 3 inch all the way.

When I raise this up do I need to have the guys on the side of it too? I
know I need to stop it when it's up but if I need to guy it so that the guy
ropes on the side can sweep as it goes up I'll need to cut a lot more trees.
So questions I still have: should I go 3" all the way, 3" to 2" or would 2"
all the way work? Guy points how many and where on the verticals should they
be mounted. Lifting the things without side guys is the possible or is it
just plain stupid?

Any tips and advice will be greatly appreciated.

Thanks,

Phil Chambley Jr
KT7J
ex KJ4NI
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