[TowerTalk] Utility Pole as Beam Support

[Roger (K8RI) on TT]

On 6/4/2014 3:31 AM, Jim Thomson wrote:
> Date: Tue, 3 Jun 2014 15:15:05 -0700
> From: "Clay Jackson" <n7qnm-lists at nwlink.com>
> To: "'towertalk reflector'" <towertalk at contesting.com>
> Subject: [TowerTalk] Utility Pole as Beam Support
>
> I just "inherited" a 50' (out of the ground, 6' buried) utility pole (crew
> was taking it out and told me that if I'd drag it off the road, I could have
> it).
>
> I'm thinking about trying to find a rotator and tri-bander to put on top of
> it; but, having no experience with such a setup; I thought I'd seek some
> advice first.
>
> So, a few questions.
>
> I'm sure someone has done this before;  would you be able to share your
> experiences?
>
> I have a friend who can weld anything from steel to aluminum and so I think
> we can fab up a mount for the rotor.
>
> Beyond that, thoughts would be appreciated on things like:
> Wind loading - how many sq ft (if any) is reasonable before I have to use
> guys (for my HyGain AV18HT the building dept made me engineer the base for
> 90K winds, WITH a "wet stamped" drawing)?
> Base - is a 6' hole filled with dirt "good enough" or do I need something
> more (if more, would a  6' hole with concrete be sufficient)?
>
> Thanks in advance!
>
> Clay
> N7QNM
>
> ##  check out old TELREX catalogues.  They depicted a setup with 3 x stacked yagis, for
> 20-15-10m on a utility pole.   It used steel  shelves, each like a huge L, bolted to the pole.
> Two thrust bearings  and the rotor.  3 x shelves in all.    The shelves were designed to factor in
> the taper of the pole.....so the mast that went through the 3 x shelves..all lined up.

What I've seen were A bracket to hold the rotator and a about a 10' mast 
run through a pair of simple sleeve bearings. All side mounted.  The 
rotator mount and bearing mounts have to allow for a lot of adjustment 
in the lateral plane so they can be aligned while keeping the mast vertical.

73

Roger (K8RI)

> # I doubt rohn 25 would fit over a standard utility pole.   Rohn 45 might just fit.   Or just custom make a
> section to fit the top of the pole.   After all the custom fabrication, cranes to lift the heavy pole, tamping down the
> fill  in 4-6 inch lifts, etc.... you might be better off to just install a freestanding tower, like a rohn hbx..or a trylon.
> 6-7  x 8 foot sections.   Watch out, a 50 foot utility pole  weighs one helluva lot !   Its not to be trifled with.
>
> Jim   VE7RF
>
>
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