[TowerTalk] Adivce Using Irrigation Pipe
Richard (Rick) Karlquist
richard at karlquist.com
Sat May 1 08:51:57 PDT 2010
Phil Chambley wrote:
> 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.
It works better to use a sleeve that fits on the outside. If you insist
on an inside piece, note that "2 1/2 inch" PVC pipe has an OD of 2 7/8
inch. 3 inch irrigation tubing, with the standard 0.050 inch wall, has
an ID of 2 7/8 inch. You can sand the PVC pipe slightly until it just
fits the irrigation tubing.
> 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.
I have a newer base design using a hinge screwed to a 3 inch PVC end
cap. The other part of the hinge screws to a flat base. This avoids
having to have "goal posts".
> 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
I built 3 verticals with the toilet flange guying and they worked fine
(IE, stayed up :-). For "permanent" installations, I still like my
original design using a 3 inch PVC coupling with little U bolts screwed
to it to form loops for ropes. The toilet flange thing is hard on ropes
because the holes are sharp.
> 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.
Instead of a lathe, you can use hole saws. I have a complete design
made from PVC plumbing parts to go from 4" to 3" or 3" to 2".
> When I raise this up do I need to have the guys on the side of it too? I
Oh yes. We forgot those a few times and the antenna went up at first
and then swang sideways.
> 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 2 inch is too flimsy. 3" to 2" works fine, but it may not be worth
the trouble to make the 3/2 transition. All 3" is still a piece of
cake to raise.
2 sets of guys is fine, but not at the top and middle. Then it
vibrates. Better 1/3 up and 2/3 up.
> 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?
See above. Gotta have side guys, on both the antenna and the falling
derrick if you use that.
> Any tips and advice will be greatly appreciated.
> Phil Chambley Jr
> ex KJ4NI
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