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Re: [TowerTalk] Lightning Protection

To: towertalk@contesting.com
Subject: Re: [TowerTalk] Lightning Protection
From: Jim Lux <jimlux@earthlink.net>
Date: Sat, 06 Jul 2013 06:53:00 -0700
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
On 7/6/13 6:22 AM, James Wolf wrote:


Through my occupation, I talk frequently to the Transector Rep.   He tells
me that over time  (< 5 years) MOV's lose their effectiveness.  I've not
heard this before.  If this is true, need to get on that.


MOVs are notorious for this. Each time they clamp a transient, they die a little bit. It's a real problem for MOVs used in line voltage applications, when too low of a voltage is selected (e.g. 130Vrms for 120V use) and the normal transients that one sees gradually kills the MOV. Eventually, the device fails: either open (providing no protection) or shorted (blowing fuses or causing fires).

Gas or vacuum gap is what you really want in an environment likely to see many transients (and I think antennas fit in that bucket).

Standler's book on transient suppression (and the website) are a good resource. $20 well spent. http://www.amazon.com/dp/0486425525


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