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[Towertalk] 25GSSB New? Baseplate

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Subject: [Towertalk] 25GSSB New? Baseplate
From: (
Date: Fri, 2 Aug 2002 04:09:15 -0600
On Thu, 01 Aug 2002 Chris BONDE <> writes:

> I thought that the concrete was mainly to lower the centre of 
> gravity for the complete antenna structure  (VE7HCB)

N4KG:  WRONG !   Center of gravity has NOTHING to do with
        resisting overturning forces in a GUYED tower (and 
        only contritubes partially in a self supporting tower).

        My (guyed) towers are set in the ground with NO concrete.
        The center of gravity is pretty high but they have
        been up for decades and withstood 90 MPH winds.

        As stated previously, the purpose of a BASE is to
        provide sufficient AREA to support the weight of 
        the tower plus the vertical forces from the guys.

        Bottom Line:  

        The EARTH supports the tower.
        The BASE spreads the load over
        sufficient AREA to prevent it from sinking.

        In areas where FREEZING occurs in winter,
        the BOTTOM of the BASE must be BELOW
        the FREEZE  LINE to prevent the base from
        pushing UP on the tower which adds to the 
        tension in the guys.
        For self supporting towers, the BASE 'couples'
        to the earth to prevent sinking AND overturning.


> This is the bases of the three legged cow milking  stool.  (VE7HCB)

N4KG:  I believe you mean BASIS and not "bases".

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