[time-nuts] Best location for a GPS antenna...?

[Bob Camp]

Hi

Oddly enough I've actually worked with an EMP simulator. They indeed put out a lot of energy. The lightning hits I've experienced are no where near EMP level events.

Bob

On Apr 12, 2012, at 9:07 PM, Chris Albertson wrote:

> On Thu, Apr 12, 2012 at 2:21 PM, Bob Camp <lists at rtty.us> wrote:
> 
>> Hi
>> 
>> Do you have a reference for 100' distant strikes routinely destroying
>> receivers?
>> 
>> Bob
>> 
>> 
> 
> The ARRL's "QST" magazine Aug -> Nov 1986 is very good and many people here
> would have access to it.
> They talk about EMP from both atomic weapons and lightening.  The EMP from
> atomic explosions is as you'd yes worse.  If can destroy most electronics
> up to 450 miles away in the worse cast (an explosion in the ionosphere.)
> 
> Lightening has vary wide band energy in its EMP and the farther you are
> away from it the lower the frequency.  So a very close strike might have
> much energy at UHF a strike 50 feet away might be only up to HF range.   So
> it couples to different length conductors depending on the distance.    My
> reference to 100 feet means you'd need some length on the feed line and
> data cables.
> 
> There is a good publication from some one at a university in Florida having
> to do with electronics on boats. I can't find it now.
> 
> 
> -----Original Message-----
>> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
>> Behalf Of Chris Albertson
>> Sent: Thursday, April 12, 2012 3:25 PM
>> To: Discussion of precise time and frequency measurement
>> Subject: Re: [time-nuts] Best location for a GPS antenna...?
>> 
>> On Thu, Apr 12, 2012 at 11:56 AM, Randy D. Hunt
>> <randy_hunt960 at yahoo.com>wrote:
>> 
>>> On 4/12/2012 1:10 AM, Heinzmann, Stefan (ALC NetworX GmbH) wrote:
>>> 
>>>> What about mounting the antenna on the side of the metal pole, with the
>>>> top of the pole extending a foot or more above the antenna?
>>> 
>>> 
>> Typically when a receiver or other radio is destroyed it was NOT because of
>> a direct strike.  A strike within maybe 100 feet is enough.  There is a
>> _huge_ EMP field around the strike.  The field will induce large currents
>> in any nearby conductors.   Even if the strike is to bare Earth many feet
>> from the antenna the potential of the earth is raised by say 1,000 volts so
>> now anything connected between ground the power has 1KV across it.
>> 
>> 
>> 
>> 
>> 
>> Chris Albertson
>> Redondo Beach, California
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> 
> 
> 
> -- 
> 
> Chris Albertson
> Redondo Beach, California
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