"Jack Painter" wrote in
news:A4bbe.17243$Z73.17113@lakeread04:

Read carefully before reacting. It gives both opinions concerning sharp
and blunt pointed Air Terminals.

Confusing, isn't it?

Oddly enough, while watching a demonstration with a Van De Graph Static
Generator at the local science center, the device was nullified in terms
of generating static when a simple metal tack was placed point up on top
of it. Also, coronal arching occurs with high voltage systems off any
pointed surface, requiring the use of metallic mesh tape to smooth out
the junctions.

http://www.amasci.com/emotor/vdg.html
http://www.infraspection.com/thermography/corona.html

Dr. Artaud


http://www.nab.org/membership/benefits/Nov00.asp

"Presently, there is much debate among lightning protection experts
regarding air terminal design. According to researchers, a sharp or
pointed air terminal has built in defenses against lightning strikes. The
strength of the electric field around the tip of a sharp air terminal is
limited by a phenomenon called "point discharge." When the electric field
around the air terminal reaches a certain strength, the current from a
stepped leader is allowed to flow through the terminal from air to
ground, before a lightning strike occurs. Overtime, the sharp point of a
conventional air terminal or lightning rod erodes due to atmospheric
conditions. This causes a rod to hold its charge and produce streamers,
providing a path for a lightning strike. Therefore, a blunt lightning rod
is more likely to intercept a lightning strike. While a sharp pointed
lightning rod is more likely to prevent a strike. The effectiveness of
sharply pointed versus blunt lightning rods is currently being studied."



http://www.marinelightning.com/science.htm

"In this respect, research reported by Dr. Charles Moore and associates
in New Mexico only two years ago finally resolved that blunt lightning
rods are actually more effective than the traditional sharp pointed
rods."