Text 2522, 100 rader
Skriven 2015-06-22 10:31:42 av Mike Luther (1:117/100.0)
   Kommentar till text 2520 av Ed Vance (14193.windowsa)
Ärende: Re: UPS units and Lightni
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Nice to chat again Ed ..

Good question!

 EV> While reading this I wondered if Your home has Lightning Rods too?

 EV> My home doesn't.

 EV> The house I rented before moving here had a metal roof and Lightning
 EV> Rods on it.
 EV> That's why I thought to ask You about this.

 EV> 73 de W9ODR

In my case there is more than one 'family' home site.  Neither has Lightning
Rods on the building.  Both have multiple antenna 'poles' that go a good way up
above the highest part of the building.  The one I am writing this from in the
City of College Station, Texas that has been here since it was built in 1947
just as a house for sale and Dad bought it when I was eight years old.  In this
neighborhood the power lines, telephone lines, cable TV lines, and heavy wood
pole support for them are all above the height of the single story homes like
ours.  As well, many of the trees are WAY above even two story homes.  With
metal antenna 'pole' or 'tower' support, that puts a very small risk of any
DIRECT strike on the building.  Thus no Rods on it,

However, protection on it is much more detailed than normal utility rules we
see in cities.  At the point where any metal based power line, telephone line
or cable connection comes down from the utiliy pole lines in the easement, the
really needed lightning strike protection needs to be added to the standard
metal ground rod where the meter is mounted.  At ground level you take about
ten qauge bare copper wire and cut it into about eight foot or so chunks.  You
then put each one like radial spokes on a wheel about two inches below the
ground and connect them all to the normal metal ground rod of the power
company.  Reason; lightning is a radio wave which does *NOT* travel on the
inside of the metal!  It travels on the SURFACE and is hunting massively for
the GROUND SURFACE where it is a hit or of focus.  Then as well, if your
telephone or cable lines are attached above the ground at the same point on the
building and they have a ground protection unit there, it too will route a
strike surge of any kind,direct or otherwise, to your radial dispense on the
surface of the GROUND where it wants to go.  Be careful if the telephone or
data metal lines are at a different point than the power line entry on the
building.  If so you need to create a MATCHING direct to ground radial dispense
point if the company has put in a one ground rod like the power company uses
and make your own direct down system if as many of them do to carry the
protection unit ground even MANY feet away to the power company standard ground
rod site.

Next point for your antenna pole or tower units on your property, *OR* if you
have, say, a TV or FM antenna isolated on your roof or so!  You need to make
*SURE* that it goes directly down to the ground to a radial set to spread the
strike on to the surface of the ground.

Obviously as a ham radio operator, you could have an antenna tower or pole away
from the building.  AHA!  If this is a vertical you should *NOT* use it as an
insulated antenna element that is fed at ground level!  The safe way to create
say 66 foot 80 meter vertical elements is to use a totally ground metal element
and SHUNT feed it from a ground level coax power line that is protected at the
bottom with a lightning protector to carry the hit surge to the 'normal' radial
near surface ground plane wires or metal flat plate you use!  Then BURY the
coaxial cable feed line back to the house where you use a radial ground
dispense point just where it touches the building on the way into your place.

The main difference between most smaller city house sites and the country
places is that there you almost always have a number of different vectors for
your antenna locations.  As well it is WAY a long way to any other property
owner's site.  In this case what you need to do is to make, say. a ten guage
wire ring at ground level all the way around your house at the bottom of the
building.  You make a number of individual eight or ten foot two inch lower
radial lines connected to this ring to dispense the hit onto the ground from
this ring.You focus a few more at any point where you have a rising coax
connection or a ground line coming down from, say, a window where you have a
normat protection fix from any feed line attached to an upper point on the
structure.

Yes, Lightning Rods are good for you in rural sites.  As well as for metal roof
conduction for the surge to ground route.  But the KEY issue for any rural
house or building is that even a strike a good way away to a tree or any other
site creates a HUGE radio wave that roars away from the hit even if it is cloud
to cloud!  That is an EMP pulse that ANY wiring in your building collects that
as it is a RADIO WAVE traveling on the SURFACE of even your internal power or
phone lines or antenna wires an can totally burn up any electronic device tied
to an affected line!  It is especially damaging to ANY unit that has a none
pig-iron transformer for a power supply!  Which was the focus of my previous
message here..,

BTW, if you need an elevated 40 or 80 meter vertical array, you can put the
bottom of it about eight feet above ground with a wire ground plane there,  You
can feed it with coaxial line connected SHUNT fed work for each element of,
say, a four tower array.  Then you can carry the coax feed line about the eight
feet above ground to your house,  Where you use the same ground protection
method before it goes into the building.

As noted I've never had any damage from the strikes since about 1974 when I
really protected the places this way.


Mike Luther as W5WQN at 1:117/100

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 * Origin: BV HUB CLL(979)696-3600 (1:117/100)