| for any point along a given direction in the far-field region of a transmitting antenna, the product of the distance from the antenna and the electric field vector produced by the antenna at that point
NOTE 1 – The field strength-distance product depends on the direction but not on the distance. Its magnitude expressed in volts is numerically equal to the magnitude of the field strength at a distance of 1 km expressed in millivolts per meter.
NOTE 2 – The field strength-distance product depends on the electrical characteristics of the antenna and the power fed to it.
NOTE 3 –The term "cymomotive force" is used in the International Radio Consultative Committee (CCIR).