[TowerTalk] engineering help? Antenna weight for US Tower TX472

[Richard (Rick) Karlquist]

On 6/11/2015 10:07 AM, kr2q at optimum.net wrote:
> Hi all,
>

> 2.  What point is the weak link for the 200 pounds?
>

Here is the surprising thing I ran into with my HDX-5106,
a MUCH bigger tower.  It has a MonstIR on top, figure
250 lbs.  Also a short mast and a prop pitch, figure
another 50 lbs.  Figure another 100 lbs for cables,
so lets call that 300 lbs.  Should be fine.

What happens is that when I get within about 5 feet
of full extension, I start to get noise and vibrations.
The working theory is that this is due to IMBALANCE of
weight, rather than just the weight itself.  The sections
start to bind a little when the overlap gets small.

I removed the antenna to change the cables in the tower,
and ran it up and down a few times, and the problem
went away under those conditions. The MonstIR has a
very flexible boom that exascerbates the imbalance
problem.  Once it starts to lean a little, the boom
flexes in the direction that makes it worse.

What I am doing as a workaround is manually stopping
the raising winch just before the problem begins.
I know from experience where this point is.

Rick N6RK