View Single Post
  #12   Report Post  
Old July 23rd 05, 05:45 PM
Richard Fry
 
Posts: n/a
Default

"Richard Harrison" wrote:
The wave along the earth at 30 MHz and above "attenuates to
negligible amplitude in a relatively few hundred feet."

________________

However this not mean that a direct ray at VHF and above cannot propagate
well on a line-of-sight path near the Earth that is tens of miles in
length--especially if a Fresnel clearance of 0.7 or better exists for the
path. Such service is produced by radiation from the transmit antenna
typically at elevation angles from zero to several degrees BELOW the
horizontal plane.

If otherwise, the service areas of TV and FM broadcast stations would be
very small.

RF