[TowerTalk] Sidemount yagis

[Earl Dery]

I have to agree with Chad, that is what I do with my side mounts here is
"Home" them against the tower when I am not using them. The sidemounts here
look to about 300 degrees roughly from 270 back through North to East South
to about 220. Worst case scenario would be with the antenna's looking East,
the sidemount is on the South leg of the Tower.

I think one might look at the load as an extra section of tower when homed
as the antenna would be about equa-distance on either side of the tower.
Certainly when hung out on one side as in my case when pointing East this
would present a totally different load on the tower which is why I built my
"swinging gate" on a frame around the tower to help equalize the load into
the whole section and not just one side.

73 Earl VE7IN


>> 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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