>From: K7LXC@aol.com
To: <towertalk@contesting.com>
>Date: Wed, 3 Jun 1998 14:15:37 EDT
>
>In a message dated 98-06-03 13:38:00 EDT, Chad_Kurszewski@csg.mot.com writes:
>
>> What are these commercial standards? Where are they documented?
>> I would like to see that information.
>>
>> I agree with Steve in that commercial stations DO take direct hits
>> and keep on ticking. I want to know what THEY do!
>>
> Well, I've seen them and worked from them but I don't have any copies.
>Motorola, all of the cellular, paging, etc. companies, state and federal
>agencies, etc. all have written standards for site ground systems. They
>generally consist of specs for the earth ground, bonding methods, materials,
>etc. as well as cable grounding, bulkhead entry, interior building grounds
>plus power, telephone and emergency power leads.
>
> Can anyone out there get me a copy of these? If you work for a
>communications company, cellular, agency, etc., I would be really grateful.
>Thanks!
>
>Cheers, Steve K7LXC
Steve,
I don't work for a cell service company or TPC (ref from the
movie "The Presidents Analyst"). But our company sells a system
that relies on a radio repeater(s) for communications to all of
the productive mobile equipment in a mine. We are in the
category of commercial users that can't tolerate outages on an
economic basis. If the repeater site is off the air, it
typically is costing our customer betweem $15K and $50K per hour
of off time. So we have been concerned with site reliability in
general and surviving lightning hits in particular. We have
developed a protection system that works well for us if properly
installed and maintained. Its function is to protect the
equipment and antennas at the site during direct hist to the
tower structure.
The job is made _MUCH_ easier and cheaper if the ground system is
planned as part of the site construction. So hams that are
considering building a house would be well advised to gain an
understanding of the issues before breaking ground. A small
amount of planning costs almost nothing and can make the
difference between a house that is completely protectable for a
few hundred dollars and one that can't be made really safe for
thousands.
Here are some of the references we used to generate the
guidelines we give our customers when they are planning a new
radio site.
1. National Lightning Protection Code, ANSI/NFPA-78-1983
2. Lightning Protection Code, ANSI-C5.1
3. National Electrical Code, ANSI-C1
4. Bodle, D.W. "Electrical Protection Guide for Land-Based Radio
Facilities", Josyln Electronic Systems, Goleta, CA, 1971.
5. Hart, William C., and Edgar W. Malone. "Lightning and
Lightning Protection", Interference Control technologies,
Inc., Gainesville, VA
6. Morrison, ralph and Warren H. Lewis, "Grounding and Shielding
in facilities", John Wiley and Sons, Inc. New York, 1990
7. Block, Roger R., "The 'Grounds' for Lightning and EMP
Protection" Second edition, PolyPhaser Corp., Minden, NV,
1993
They are all recommended reading on the subject.
73, Eric N7CL
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