Abstract :
The paper, describes how it is possible to determine the minimum radius at which a four-aerial Adcock direction-finder may be calibrated for instrumental error without introducing spurious effects due to the. proximity of the calibrating. Transmitter to the direction-finder. It is shown that this minimum radius depends upon the spacing of the aerials, the wavelength, and the inherent accuracy of the direction-finder to be calibrated. In most cases of practical interest the minimum radius is found to be between 0.6¿ and 3.5¿. Such distances, while usually easily attainable on the short wave band, may not be possible in the case of medium or long wavelengths.
