A short-wave Adcock direction-finder

This paper gives full details of the construction and performance of a short-wave aural Adcock direction-finder of the coupled type with a working wavelength range of from 35 to 70 metres (frequency 8.6 to 4.3 Mc.). It describes how the design of the instrument is based on the principles brought to light in an earlier investigation. It deals with its design in respect of polarization error, pick-up factor, and instrumental error, and describes experiments by which these properties were measured. The values obtained for these were as follows: standard-wave error, 3° to 8°; pick-up factor, 4.5 to 6 metres; instrumental error, 2° to 3° at maximum. The apparatus is considered to constitute a satisfactory direction-finder from a practical point of view, though it will be possible in future models, one of which is already under construction, to take advantage of the experience gained to obtain an instrument with lower instrumental and polarization errors and higher pick-up factor.