View Single Post
  #4   Report Post  
Old September 5th 05, 02:51 PM
Walter Maxwell
 
Posts: n/a
Default

On Sun, 4 Sep 2005 22:24:24 -0500, (Richard
Harrison) wrote:

Reg, G4FGQ wrote:
"The rods are both wasted effort and wasted copper (or aluminum)."

Likely so.

Radials are placed to capture displacement current to and from the
vertical radiator, to prevent its travel at a high densitY in the earth
where it would cause high loss.

B, L, & E found that more radials were better than longer radials. More
radials put the displacement current capture closer to the vertical
radiator where its density is higher. Radials need extend outward only
as far as there is any current or until a point of diminishing returns
is reached. At great distance from the vertical radiator, the earth`s
crust, which may be affected, has a great cross section, so current
density is low and so are losses. There is much less displacement
current to deal with near the ends of radials. Displacement current is
low near the ends of the radials and the earth out there has a large
cross section and a low resistance. Due to skin effect, the closer to
the surface, the higher the current. This is especially true at high
frequencies.


Hi Richard,

You've just presented the best abstract of BL&E I've seen ever seen.
It should be must reading for anyone who asks questions concerning the
purpose of radials, how many, and how long.

Walt, W2DU