IEEE 291-1969

Most measurements with which radio wave propagation is concerned involve the measurement of field strength. Thus, the determination of power radiated from an antenna (Section 3) depends principally upon the measurement of field strength, especially in the low-frequency and medium-frequency bands. Standard methods for the measurement of this fundamental quantity are outlined.



New IEEE Standard - Superseded. Two standard methods for field-strength measurement are described. The standard-antenna method consists of measuring the received power or open-circuit voltage developed in a standard receiving antenna by the field to be measured and computing the field strength from the measured voltage and the dimensions and form of the standard antenna. The standard-field method consists of comparing voltages produced in an antenna by the field to be measured and by a standard field, the magnitude of which is computed from the dimensions of the transmitting antenna, its current distribution, the distance of separation, and effect of the ground. The measurement procedures are outlined, including calibration of commercial field strength and extension of the methods to microwave frequencies. Methods for measuring power radiated from an antenna under several different conditions are briefly presented, and the important considerations for securing useful and accurate measurements are described.