Lightening damage

Why would lightning avoid striking a grounded tower?

John KK9A

Richard Fjeld rpfjeld at outlook.com

I'm trying to avoid taking anyone's side on this discussion.  I wanted to
say that I worked for a  company that had towers throughout the state which
were several hundred feet tall.  Over the years, I only saw one that took a
hit.  The company was so certain their grounding specs had not been
followed, that they made the contractor dig up the entire grounding layout.
It revealed the specs had not been followed.  

Certain radio and TV services need to operate 24/7 and can't shut down when
lightening threatens.  Their grounding methods apparently prevent the towers
from being hit .

Rich, n0ce

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[Mark Bayern-3]

> Certain radio and TV services need to operate 24/7 and can't shut down when
> lightening threatens.  Their grounding methods apparently prevent the towers
> from being hit .

My experience as a 1st Phone running AM broadcast stations is that the
towers _are_ hit by lightning. This was in the early '70s and all base
insulated towers had a lightening arrestor across the insulator.
Normally the transmitter would drop out momentarily. Most of the
stations had two 833s for the the finals. Guess they can handle some
abuse.

Once I lost a selenium rectifier but that was most likely a power line hit ...

Mark AD5SS
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[k6dgw]

I supported myself at university as an engineer at the only TV station
in town.  Transmitters [10 KW visual, 5 KW aural] and studio were in a
building at the base of a 400' tower on a ridge overlooking town. 
Studio wiring was in trenches in the concrete floor covered with fairly
heavy steel plates.  As Mark mentioned, our tower did get hit
occasionally, but it was not a common lightning area.  It knocked one or
both transmitters off the air once or twice, sometimes it didn't.  Did
not seem to bother the uwave antennas or equipment.  What it did do in
the control room, every time, is sound like you were inside a big bell
as all those trench covers rang. [:-)

73,

Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

On 11/7/2017 9:26 AM, Mark Bayern wrote:

> My experience as a 1st Phone running AM broadcast stations is that the
> towers _are_ hit by lightning. This was in the early '70s and all base
> insulated towers had a lightening arrestor across the insulator.
> Normally the transmitter would drop out momentarily. Most of the
> stations had two 833s for the the finals. Guess they can handle some
> abuse.
>
> Once I lost a selenium rectifier but that was most likely a power line hit ...
>
> Mark AD5SS
>

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[Charlie T, K3ICH]

Why would lightning avoid striking a grounded tower?

John KK9A


Depleted ground charge.
THE reason for lightning rods.....

Chas



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[Nr4c]

Are you sure that they are not being hit, but are so well bonded that the strike goes directly to ground?

Sent from my iPhone
...nr4c. bill

> On Nov 7, 2017, at 11:58 AM, <[hidden email]> <[hidden email]> wrote:
>
> Why would lightning avoid striking a grounded tower?
>
> John KK9A
>
> Richard Fjeld rpfjeld at outlook.com
>
> I'm trying to avoid taking anyone's side on this discussion.  I wanted to
> say that I worked for a  company that had towers throughout the state which
> were several hundred feet tall.  Over the years, I only saw one that took a
> hit.  The company was so certain their grounding specs had not been
> followed, that they made the contractor dig up the entire grounding layout.
> It revealed the specs had not been followed.  
>
> Certain radio and TV services need to operate 24/7 and can't shut down when
> lightening threatens.  Their grounding methods apparently prevent the towers
> from being hit .
>
> Rich, n0ce
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

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