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Re: [TowerTalk] 80' tower in SF Bay area (update)

To: "'KA9OFM John Garrett'" <ka9ofm@gmail.com>, <K7LXC@aol.com>,<towertalk@contesting.com>
Subject: Re: [TowerTalk] 80' tower in SF Bay area (update)
From: "JC Smith" <jc-smith@comcast.net>
Date: Tue, 1 Aug 2006 07:41:58 -0700
List-post: <mailto:towertalk@contesting.com>
Hi John,

Yes, my plans call for ~6" above the soil level.  I'm on a slight slope
(3" - 4" fall over the 9' the hole covers) and I've been pondering whether
to just do the top of the pier parallel to the ground or do it horizontal
with a crown in the center.  I'm thinking it will look a little a little
more professional if it's horizontal so I'll probably do that (with the
crown).  That's how I did my other tower and the water runs off great.

I don't have the bottom section of the tower yet, and it's very heavy anyway
(279 lbs.) and would be difficult to work with while leveling the base.
Also, it's not a parallel-sided tower so I have to use a different technique
to get the base level and plumb.  I'm practicing with the base outside the
hole right now, to develop the best technique and a jig to do it once I get
in the hole with the rebar, etc.  I also got some hints from the
manufacturer on how to do all that.  I must admit, this is the scariest part
of the project (to me anyway)... a lot scarier even than working 80' above
the ground to install the antennas.  You only get one shot at pouring the
base.

Thanks for your advice.

73 - JC, K0HPS


-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com]On Behalf Of KA9OFM John Garrett
Sent: Monday, July 31, 2006 10:29 PM
To: jc-smith@comcast.net; K7LXC@aol.com; towertalk@contesting.com
Subject: Re: [TowerTalk] 80' tower in SF Bay area (update)

One final suggestion - Make your tower base a few inches higher than the
surrounding earth. I always make my pours 4 inches higher. This will allow
water to run off the base during a rain instead of possibly standing on the
base. Which would eventually allow rust to begin. You can even put a slight
angle on the base top so water runs off rapidly, but if you do that then
don't overdo the angle of the top of the base as only 1 or 2 degrees is
necessary.

The watering of the base after pouring is needed too to help prevent
premature drying. Just water the base like it was your grass daily for the
1st week. Some suggest watering for the full curing time.

Waiting 28 days before erecting the tower works fine if you use standard
concrete that has no added chemicals to speed drying. Added chemicals only
cut the dry time in half anyway and the added cost is really not worth it if
you can just wait the additional 2 weeks. There is a lot of work that can be
completed around the base after a week and the forms are removed. That will
probably keep you busy enough  not to notice the time passing and at the end
of the month you will be ready to complete the job. Great time to complete
the grounding system, run your coax and cables, and so forth.

One other thing when I pour a base I always attach the bottom section of the
tower so I can make certain that it will be straight. I check it with a
level and also place a leveling plum in the inside of the tower and let it
hang down to about the bolts to make sure it is hanging in the center as it
should. One look and it will show you if you are off.

You probably already know these things, but I thought it may be a point that
could easily be overlooked. I certainly hope you will be delighted with the
end result.

73
John, KA9OFM


On 7/31/06, K7LXC@aol.com <K7LXC@aol.com> wrote:
>
>
> In a message dated 7/31/2006 11:20:47 A.M. Pacific Daylight Time,
> john@iguanavilla.com writes:
>
> >  I'm guessing that the earth was already disturbed from  installing the
> 9 ft
> square x 1 1/2 ft. thick footing that the manufacture  (AN Wireless)
> recommends.
>
>
>        Well, sort of. The  undisturbed part is the sides. Obviously the
> dirt
> you dig out is disturbed but  since it doesn't have anything to do with
> the
> base installation, it's a  non-issue.
>
> Cheers,
> Steve    K7LXC
> TOWER TECH -
> Professional tower services for hams
> Cell: 206-890-4188
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
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