The Radiation Characteristics of a Vertical Half-Wave Antenna

Extensive measurements have been made of the field distribution about a vertical antenna operating at 29 megacycles over sea water. With the help of a small, nonrigid airship observations were made at various altitudes which permitted the plotting of the space characteristic and the determination of the attenuation as dependent on altitude. The experimental results are compared with field intensities computed for the given physical conditions from the theoretical expressions of Sommerfeld and Strutt. Of interest is the manner in which the field is attenuated in the immediate vicinity of the ground plane and the marked effect on the general intensity distribution of the effective height of the antenna above ground. Details are given of the design of the apparatus required for carrying out the measurements.