Field-strength measurements on Daventry 5XX

The paper describes a series of measurements made in different parts of Southern England on the transmissions from Daventry 5XX. An intensive survey of Cornwall indicated a rapid attenuation of field strength on crossing Bodmin Moor. Beyond this area symmetrical contours were observed. Their existence is attributed to the large, irregularly shaped moor, rising to the hill ¿Brown Willy.¿ This conclusion was further tested in Devon, where confirmation was obtained. Experiments were made on the effects of coastal refraction, and on energy from the upper atmosphere. Negative results were obtained which proved that the effects, if any, were small.