Dave wrote:
"Rick (W-A-one-R-K-T)" wrote in message
news
When electrically grounding one's station, is there any particular
advantage of a single 8-foot ground rod over two 4-foot ground rods, or an
8-foot length of heavy gauge wire buried 6-12 inches under the ground?




yes. first there is the electrical safety code that you must comply with
which i believe generally calls for 8' rods. 4' rods may not be below the
frost line in the winter so may not provide any useful grounding for part of
the year. shallow buried wire has the same problem.

on rf issues, lots of shallow buried radials can help reduce ground loss
under certain antennas... but these are not substitutes for good electrical
safety grounds.


The NEC allows a wide variety of electrical safety grounds (and,
interestingly, a ground rod is not usually allowed as the only grounding
electrode). The old standby of "cold water pipe" is specifically not
allowed any more (too many places with plastic pipe from street to house).

The preferred ground in most jurisdictions is a concrete encased
grounding electrode (aka a Ufer Ground, after the inventor's name Herb
Ufer).. 20 ft of appropriate conductor encased in concrete.

As far as rods go, you can dig a trench and lay it sideways and meet the
code requirement. 2 rods 4 feet long might meet code (if all of the rod
is buried and they are far enough apart).


However, in addition to any regulatory requirements, there's a
difference between a "good ground" for
a) electrical safety
b) RF
c) lightning

A grounding system that's good for one isn't necessarily good for the
others.


There's a good writeup on grounds, with particular attention to
antennas, cable TV, telephone, etc. at Mike Holt's website (He's a
electrical code guru that does seminars, etc.)

http://www.mikeholt.com/ is the site, look for the "low voltage
handbook", which is a free download and has all the relevant code
sections explained, with diagrams, etc.