Measurement of Radiation from Selected TD-2 Microwave Relay Stations

The optimum frequency band for satellite communication systems is generally agreed to be between 1 and 10 Gc. Frequencies in this band are, however, already allocated and or assigned. One solution to this spectrum occupancy problem is frequency sharing, and one of the systems in this band with which a satellite system might have to coexist is the TD-2 microwave radio relay sstem (3.7-4.2 Gc). This paper presents the measured radiation characteristics of several representative TD-2 transmitting terminals. Both ground and airborne measurements are discussed. It is concluded that, subject to some precautions, back-and side-lobe patterns measured in the horizontal plane on an antenna range with ground effects minimized can be used to predict radiation in the vertical plane from these same antennas placed over actual ground. Such a technique, of course,, presupposes that the antenna of interest has been properly designed to somwhat suppress side and back lobes.