[TowerTalk] Several questions for the group

[Bill Putney]

John,

I did mine according to the Rohn manual. There is a lot more engineering detail
in the manual that the little sheets that come with the tower. It's for guyed
Rohn 25 with a pin but the pad should be the same.

The manual calls for 2' diameter hole 4' deep with a 4" 2' square pad on the
top. The plans don't really call it out but I reenforced the concrete with 6
1/2" rebars made into a reenforcing cage. They go almost to the bottom of the
hole and are bent over at the top and held up in the pad by dobes to support
them while the concrete was being poured. You should lay out a piece of plywood
big enough to span your forms with the hole pattern for your base plate. Get
the Rohn (or other high grade structural) J bolts and set them in the concrete
using the plywood template. I tied my J bolts into the rebar. After reading
some of the information on this group I think that was a bad idea. I think now
the J bolts should "float" if possible to avoid having lighting try to take the
J bolts to ground causing damage to the concrete pier. I would suggest using
something like 6 bag concrete.

The depth and diameter of the hole (according to the manual) is for "standard"
soil. The implication is that if your soil is marshy or sandy your foundation
should be adjusted for those conditions. Most of what the foundation has to
deal with is the down force from the weight of the tower and antennas along
with the down force from guy tension. There is some lateral force at the bottom
of the tower but that's fairly light for a multilayer guy system. Rohn calls
for two sets of guys for a 50' tower. I'm not sure what a hinged base will get
for you. You could put up a few sections and walk them up I guess but I
wouldn't try the whole 50' that way unless you built a fancy yoke to carry the
tower from several places along it's length.

- Bill

On Nov 1,  7:58am, brewerj@squared.com wrote:
> Subject: [TowerTalk] Several questions for the group
>
> Just resubscribed again, and am planning to put up a modest tribander/6M
> stack on
> a 50'  Rohn 25 tower and have a couple questions.
>
> 1) What kind of base is required for a guyed 25 tower using a hinged plate
> base?
> I've got the Rohn 25 info pack and cant see any specific info regarding
> this config?
>
> 2) If I use a 25' tree as a "boom" can I pull/walk up the tower into place
> with the hinged
> base?
>
> 3) Does Mosley sell replacement aluminum tubing for their antennas? I need
> one
> section...
>
>
> Thanks in advance
> John
>
>
> List Sponsored by AN Wireless:  AN Wireless handles Rohn tower systems,
> Trylon Titan towers, coax, hardline and more. Also check out our self
> supporting towers up to 100 feet for under $1500!!  http://www.anwireless.com
>
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>
>-- End of excerpt from brewerj@squared.com



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