"Richard Harrison" wrote in message
...
Reg, G4FGQ wrote:
"According to textbooks, the field strength from 1 KW at 1 kilometre
=
300 millivolts per metre."

Terman agrees with Reg`s signal strength produced by 1 KW radiated
at a
distance of 1 kilometer of: 300 millivolts per meter.

There are some conditions. The transmitting antenna is vertical and
short compared with a 1/4-wavelength. It is nondirectional in a
horizontal plane. The height of both antennas is low enough so that
the
space wave does not dominate propagation between them. Terman`s
field
strength derives from the equation first given by Sommerfeld and
includes a factor aounting for ground losses.

Best regards, Richard Harrison, KB5WZI

========================================

Richard, thanks for the confirmation.

All you have to do now is calculate from the field strength the power
available to a matched receiver at 20 MHz with a vertical receiving
antenna 1 metre high.

If I tell you the antenna's radiation resistance is 1.758 ohms then
you can forget about the frequency.
----
Reg.