[Antennas] Antenna Vibration

[A10382]

Any metal object that continuously vibrates (resonates) will eventually be
subject to metal-fatigue.  The vibration might noticeably shorten the life
of the item and might even lead to a future catastrophic failure.

Most antennas are designed to not resonate (self-oscillate) at any
mechanical frequencies they might normally be subject to (wind, ground
vibrations, and from climbing).  Occasionally, a combination of
manufacturing irregularities, design deficiencies, installation or mounting
problems (even loose bolts, poor welds, or a non-stable base), etc. do in
fact allow the structure to vibrate.  These can usually be fixed with
mechanical dampers.

The problem should definitely NOT be ignored.  Knowing about it may deem you
to be 'negligent' if the structure fails at a later date.

If it were my tower, I'd be documenting this (by registered mail) to the
tower manufacturer and asking for suggested solutions.

73, Frank
._._.



----- Original Message -----
From: "Rob Matherly" <w0jrm@arrl.net>
To: <antennas@mailman.qth.net>; "James E Boyd" <kb9vtm@juno.com>
Sent: Tuesday, January 21, 2003 1:49 PM
Subject: Re: [Antennas] Antenna Vibration




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