If you are looking for a good explaination of tower installation and analysis
check out the work done by Kurt Andress, K7NV. His work can be found
at http://yagistress.freeyellow.com/towers1.html
He goes into great detailed analysis using Finite Element Analysis (FEA)
in each type of tower installation.
Joe
AG4BW
|--------+----------------------->
| | K7LXC@aol.com|
| | |
| | 05/31/01 |
| | 08:05 AM |
| | |
|--------+----------------------->
>--------------------------------------------------------------------------------------------------------|
|
|
| To: bradrehm@texas.net, coneal@ma.ultranet.com,
towertalk@contesting.com |
| cc: (bcc: Joseph Mowery/N13/N10/NDept/NSWCDD)
|
| Subject: Re: [TowerTalk] Pier pin vs. burying in concrete
|
>--------------------------------------------------------------------------------------------------------|
In a message dated 5/30/01 9:13:11 PM Pacific Daylight Time,
bradrehm@texas.net writes:
> The really neat thing about the pier pin approach is that wherever you
> locate the guys, the tower will rotate around the pin to equalize tension
on
> the guys.
Huh? With 670# tension on the top 1/4" guys and 400# tension on the
bottom 3/16" ones, how does the tower rotate? Can you actually see it move? I
suggest that your guy tension is too low if you can see the tower torquing.
The purpose of the pier pin is to equalize leg compression since all of
the tower weight and compression is focused on one spot instead of three
separate and immovable ones. A pier pin is mostly used on BIG towers where
you're talking about BIG forces. Rohn 45G is a relatively small tower so the
forces are magnitudes smaller than the typical commercial pier pin
installation.
I don't like the pier pin for typical ham installations simply because
it's more work (a pain in the butt) and fooling around than a
base-section-in-concrete since you have to use temporary guys until you get
the first set of real guys hooked up.
Plumbing the bottom section in concrete is easy - you just put a
comealong on each leg and pull them until it's plumb.
Cheers, Steve K7LXC
Tower Tech
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List Sponsor: Are you thinking about installing a tower this summer? Call us
for information on our fabulous Trylon Titan self-supporting towers - up to
96-feet for less than $2000! at 888-833-3104 <A
HREF="http://www.ChampionRadio.com";>
www.ChampionRadio.com</A>
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FAQ on WWW: http://www.contesting.com/FAQ/towertalk
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