Experiments with Underground Ultra-High-Frequency Antenna for Airplane Landing Beam

Experiments are described on the electrical properties of an ultra-high-frequency transmitting antenna operating very near to and below the ground surface. The work was done with the purpose of locating the landing beam in the center of an airport in order to secure a steeper approach path and to provide for landing service for different wind directions. The effect of the proximity of the ground to the transmitting antenna upon the low angle distribution of energy in the radiated field and upon the polarization of the field is described. An approximate mathematical analysis is given of the mechanism of setting up a landing path when the transmitting antenna is below the ground surface.