Antenna mean wind torques: a comparison of field and wind-tunnel data

Accurate information about the action of wind on antennas is required for the sizing of antenna motors and for reliable prediction of antenna pointing errors in windy weather. For these purposes, wind-tunnel data were obtained 40 years ago, using a scaled antenna model. However, their accuracy has been challenged, since they have not yet been verified in a field environment (i.e., for a full-sized antenna, with real wind instead of a steady air flow, and with the influences of the actual terrain, etc.). The purpose of this investigation was to obtain appropriate field measurements, compare them with the available wind-tunnel data, and verify the usefulness of the wind-tunnel data. For this purpose, we measured the steady-state (mean) wind torques of the NASA Deep Space Network 34-meter antenna, calculated the dimensionless wind torques for a variety of wind yaw angles and antenna elevation angles, and compared them with the wind-tunnel data. The results showed that the differences between the wind-tunnel torques and the field torques were less than 10%.