"Telamon" wrote in message
...

He does not understand the technical terms he uses either. He will not
answer a simple question on them.

I already gave you a definition of how field strength contours are employed
and how the FCC uses them.

Keep in mind that the FCC's principal technical function is that of
regulating interference. Field strength, calculated or measured, is the
metric the FCC uses to determine if there is interference potential in an
application for a new station or in a change application. We are not
interested in the nature or physics of propagation... we are interested in
HOW MUCH signal there is at specific points removed by specific distances
from an antenna or antenna system.

Further, radio stations use coverage maps to show advertisers where the
signal reaches. Such maps are labeled in mV/m for AM and dBu for FM; these
are the standard measurement units for the radio broadcast industry.

In either case, the data for the FCC or the contours on a coverage map when
based on the measured free space electromagnetic field using a standard or
calibrated antenna to determine the field strength of a station. In many
cases, the AM coverage areas are determined by calculations based on power,
antenna efficiency and ground conductivity to determine contours of specific
and desired intensity. In the FM service few stations ever do measurements
or even have the equipment to do it... it's all calculated and the FCC does
not require measured field strength readings, although stations may submit
measured field strength readings to prove a specific application is viable.

An AM station, when first licensed or when making a significant change in
facility, will do field strength readings on a number of points on a number
of radials at specific distances from the transmitter. A directional AM will
have more radials, as the monitor points must show actual measured field
strength in the nulls, which are there to protect other stations from
interference, must be measured to the sides and at the center of each null.
The location of the directional monitor points are, in fact, part of the
station license.