[TowerTalk] base section

[Lonberg, Hank]

Arliss:

I would agree with you if the rotating platform is below the last guy set,
i.e., between the last guy point and the base. However if it is above a guy
point the guys take the torsion out and very little should get transmitted
to the base point.

Do the free-body diagram and see for yourself. So you are right and Steve is
right depending on where the rotating mechanism is placed in the system.

73

Hank Lonberg  P.E. / KR7X


	-----Original Message-----
	From:	W7XU Arliss [SMTP:w7xu@dtgnet.com]
	Sent:	Thursday, November 30, 2000 12:55 PM
	To:	k1my@nlis.net; towertalk@contesting.com
	Subject:	Re: [TowerTalk] base section

	Re: fixed base vs. pier pin -- at least for Rotating Tower Systems,
	when K5IU was the owner I believe the "prime directive" was no pier
	pins.

	73,  Arliss  W7XU

	K7LXC@aol.com wrote:
	> 
	> In a message dated 11/30/00 6:08:28 AM Pacific Standard Time,
k1my@nlis.net
	> writes:
	> 
	> > I understand that for a fixed tower (rotating or stationary
antennas) that
	> >  a pier pin is the strongest solution; but what about a rotating
tower? Is
	> >  it a logical conclusion that the best way to go is with a
buried section
	> >  because of the potential rotational moment?
	> 
	>     Where's your bottom bearing going to be? Is it going to go on
a section?
	> 
	>     If your question is whether the bottom (non-rotating) part of
the tower
	> should be a pier pin or buried section, I don't know if it makes
much
	> difference. I think the best scenario is to have the bottom
bearing just
	> above a set of guys; that way there's not much rotational torque
below the
	> bearing. A big rotating tower generates a lot of torsion on the
tower as it
	> winds up to start and coasts to a stop.
	> 
	>     If it was my tower, I'd go for a buried section - I don't like
messing
	> with a pier pin and temporary guys.
	> 
	> Cheers,    Steve    K7LXC
	> Tower Tech
	>

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