[time-nuts] GPS antenna selection — lightning

Alexander Pummer alexpcs at ieee.org
Fri Aug 5 20:28:24 EDT 2016


lightening protection:

http://www.ul.com/wp-content/uploads/2014/04/LightningProtectionAG.pdf

73
KJ6UHN
Alex

On 8/5/2016 1:51 PM, Attila Kinali wrote:
> Hi Eric,
>
> On Fri, 5 Aug 2016 10:37:28 -0400
> Eric Scace <eric at scace.org> wrote:
>
>> A GPS antenna and its coax line that is installed next to a window is no
>> different from the same antenna/coax installed one meter outside the window…
>> or 10 meters away outside the window. All three installations are
>> effectively “outdoors” from an electromagnetic viewpoint, and all three need
>> effective surge protection from lightning-, cloud-, and precipitation-
>> induced voltage surges.
> Please please please do NOT spread dangerous information like this!
>
> While it is true, that an indoor antenna is suceptible to surges like
> an outdoor antenna, it is not true that an outdoor antenna is equivalent
> to an indoor antenna when it comes to lightning protection.
>
> Because an outdoor antenna can be _directly_ hit by a lightning.
>
> To protect the house and its inhabitants from the lightning strike,
> an external antenna needs to be either lower than any lightning rod
> and within its 45m ball or needs its own conductor and grounding
> to discharge any lightning energy and thus preventing it from following
> the antenna cable into the house.
>
> Please be aware that the grounding of the antenna is not to protect
> the equipment from surges, but to prevent conduction of the lightning
> into the house that could cause electrocution and fires.
>
> 			Attila Kinali
>



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