[AMRadio] New Tower

[Rob Atkinson]

I don't know how far along you are in your plans, but if it is not too
late to reconsider, I'd think about a different setup, with your goal
of tilt-over in mind.   We are all going to get there eventually if we
have not already.  If all you need is the A3 at 40 feet, I'd go with a
free standing aluminum tower.  It will be so light weight, it will
hinge over much more easily, and hold the A3 with no trouble.
Further, I'd run an aluminum mast tube through the top section all the
way down and put the rotator at the base where you can get to it on
the ground, and keep its weight off the top of the tower.  put the
beam only a foot or two above the top of the tower.   The whole thing
will weigh much less than R25 and put much less stress on your
bracket.

73

Rob
K5UJ

>
> -----Original Message-----
> From: amradio-bounces at mailman.qth.net
> [mailto:amradio-bounces at mailman.qth.net] On Behalf Of Bernie Doran
> Sent: Friday, April 29, 2011 10:07 AM
> To: Discussion of AM Radio in the Amateur Service
> Subject: Re: [AMRadio] New Tower
>
> Rick, you would be far better off to simply find someone to climb the tower
> for you.  An Attachment point on a "shed" 12 feet up will not even come
> close to handling the moment produced by that tower.   Bernie
> ----- Original Message -----
> From: "Rick" <rickb at tx.rr.com>
> To: "'Discussion of AM Radio in the Amateur Service'"
> <amradio at mailman.qth.net>
> Sent: Friday, April 29, 2011 11:08 AM
> Subject: [AMRadio] New Tower
>
>
> I am erecting a new 40' Rohn 25 tower and need some advice on how much
> stress it can take while standing it up. My tower climbing days are well
> behind me, so, that is not an option. I have the hinged base mounted in a 2
> ½' X 2 ½' X 3' deep rebar reinforced block of concrete. I have a sturdy wall
> bracket at about 12' on my shed to which the tower will be mounted. I am
> undecided about guy wires at this time since less than 30' will be
> unsupported. I am installing a Cushcraft A3 tri-band beam about 5' about the
> top section. The rotator will nest inside the tower. With that said, my
> question is:
>
> If I put a compound rigging with one set of pulleys attached to the shed and
> the other attached to the tower, where would be the best place to mount the
> tower pulleys to get the greatest leverage for lifting and still provide
> adequate support for the tower as it is being raised? The tower will not be
> lying flat on the ground, of course, due to the size of the antenna. I
> assume a location above the center point of the tower would be best, but how
> far above do I put the pulleys without endangering the integrity of the
> tower?
>
> Thanks,
> Rick/K5IAR
>