[Antennas] Antenna Vibration

2003年1月21日 10:38:10 -0600

Jim, it's been about 50+ years since I studied Structures in undergrad
school, but I would recommend that you take steps to damp that
vibration before damage results. It could stay like it is for the next
ten years and do nothing but annoy you, but it could also be slowly
weakening some part that will fail one of these days.
 When the wind blows, most towers with beams, etc. will
intermittently vibrate "a little" as the unbalanced wind forces on the
beam(s) causes them to exert unbalanced forces and torques on the
tower itself.
But, a continuous vibration without wind excitation suggests something
else is going on. You might contact the manufacturer, describe your
installation in detail and get an second opinion.
As you describe it, there is a pronounced resonance in the structure
that needs to be uncovered and removed.
73/72, George
Amateur Radio W5YR - the Yellow Rose of Texas
In the 57th year and it just keeps getting better!
Fairview, TX 30 mi NE of Dallas in Collin county EM13qe
K2 #489 IC-765 #2349 IC-756 PRO #2121 IC-756 PRO2 #3235
----- Original Message -----
From: "James E Boyd" <[email protected]>
To: <[email protected]>
Sent: Monday, January 20, 2003 8:29 PM
Subject: [Antennas] Antenna Vibration
> Dear Group,
>> Has anybody had this problem before?? This year I've really noticed
my
> tower vibrating during the wind blowing. I'm not talking about wind
> storms. But just any breeze. Its getting so bad that you can hear
it in
> the house. I've tried turning the beams to see if that will stop
it, but
> only for awhile. My tower is only 40 feet tall. I only have 2
small
> beams on top of the one thats next to the house. But I'm wondering
if
> the vibration could even go down into the concrete and crake it?
When
> you put your hand on the tower, this puppy is really dancing to a
tune.
> So the question being, can anything be done to slow the tone down.
I
> don't know what musical note my tower is playing, but it must be
around
> low "C". Any help will be really appreciated.
>> 73
> Jim
> kb9vtm
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