I have been following the lightning/grounding threads on this list for quite
some time and have read articles and literature from ICE and PolyPhasor.
Now I would like to ask some practical questions of the experts here before
I invest some money in lightning abatement.
Here is my situation (as briefly as possible):
I live at near the top of a hill on a heavily wooded four acre lot full of
70-90 ft hardwood trees. I have little open land, so my antennas will
mostly be in the woods around 50 - 300 feet from my house. The clay-like
soil is damp most of the summer which makes for shallow root systems leading
to big live healthy trees falling over every year. I am hesitant to sink a
lot of money in a tower only to have a tree fall on it or its guy wires.
But being a low-band guy, I am prepared to put up a lot of big homemade wire
arrays and irrigation tubing verticals which would not break the bank if a
tree fell on them.
The thing that has kept me from much antenna activity is that we have a
large number of violent thunderstorms around here and my woods take direct
hits at least once or twice a year. I have been lucky so far, but neighbors
have had lots of electronics fried over the last few years.
I think I need to consider having a lightning grounding system in the woods
where the antennas are and one at the house where all the utilities enter as
follows:
Woods Ground:
- Even though most of my antennas will be wire arrays, I need to establish a
grounding system in one spot in the woods similar to how one would protect a
tower. This means burying thick wire or copper tape going radially outward
from a single point with ground rods exothermically welded to the radials at
intervals of twice the length of the rods. The feedlines to all antennas
and the control and power lines to all matching systems will be grounded at
this point before they start their run to the house. My theory is that
this is to dump as many electrons into the ground in the woods before they
want to travel hundreds of feet through the inductance of the lines to the
house. Feedlines and control lines will go underground from that grounded
point in the woods to the entry bulkhead at the house.
House Ground:
- All utilities and my ham lines will enter the house through two bulkheads
(the existing power utility one and one the new one for the rest) that are
next to each other and bonded through copper strap. The lines will be
protected by PolyPhasor or ICE suppressor feedthroughs. Currently all the
utilities come underground from the opposite direction of my feedline run
but they will all run in straight lines to one end of the house where the
bulkheads will be. The bulkheads will be bonded by copper strap to a halo
ground consisting of thick wire or copper strap running around the house
underground at a distance of about ten feet out. The halo ground will have
buried ground rods exothermically welded to it at intervals of twice their
length.
Here are my questions:
- Is this basic two point philosophy right? Is it overkill or not enough?
- The halo will be incomplete since a paved driveway comes right to the
garage on the other end of the house. The halo will a be very long "C"
shape with the bulkhead end of the house at the closed end of the "C" and
the driveway end of the house at the open end. Is this ok or will an open
halo be far less effective than a closed one? I can extend one leg of the C
shaped halo past the house and along the back of the driveway for another 20
feet. Is this worth the trouble at the far end of the C?
- What is the cost and effectiveness tradeoff between copper tape ground
radials and just using thick (#4?) wire?
- The natural gas line enters the house at the meter nearby the electrical
bulkhead. What do I do with that? I don't think I have ever read anything
about the gas line and lightning protection.
The other reason for lightning abatement is that I run a software consulting
business from my home and I have a number of servers that I would rather not
have blown to a crisp. Presently, I run all wireless network in the house,
so only one utility comes to each server.
Thanks in advance for your comments.
Dudley - WA1X /8
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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