[TowerTalk] Sidemount yagis

[Kurszewski Chad-WCK005]

> poster's tower was 25G so there's not a lot of engineering overhead left
> to 
> take care of additional antennas and also the forces from the sidemount.
> With 
> a 3-foot sidemount the side torque is increased by a factor of 3 so that
> can 
> create some big stresses down the tower.
> 
While I don't disagree with everything said, I would
like to add two things.

The sidemount (assuming swinging gate type) only needs to
long enough to be slightly more than the tower width.  For
Rohn 25, this is somewhat larger than 1', but certainly
CAN be less than 3'.

When not "in use", the swinging gate sidemount can be
rotated such that it is against one of the stops, ie. tower.
If done in the correct direction (prevalent wind direction
taken into account), the equivalent torque arm is slightly
more than one-half the tower diameter.  In the case of
Rohn 25, less than one foot, assuming the swinging gate
arm is minimum length, as stated above.

Regards,
Chad  WE9V

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