to +75°, leels of interference about 20 dB to 35 dB higher than the CCIR levels should be tolerable. However, as the declination of the satellite is approached, this margin falls to about 13 dB. Figure 1 shows the levels corresponding to the VLA bands from CCIR Report 224-4, the maximum sensitivity levels for the VLA, and the predicted flux density levels from the satellites, including both thermal and transmittergenerated radiation. For the thermal radiation, unit emissivity and a temperature of 330 K are assumed. Consider first the response to the thermal radiation. With all of the satellites in the far side lobes of the antennas, the response of any pair of antennas in the array consists of 60 sinusoidal components, the phases of which may be considered random. The rms level of the combined response is thus greater than that for a single satellite by a factor of /60 or 8.9 dB, and the effective flux density is midway between the curves for one satellite and 60 satellites in Figure 1. Thus the 20- to 30-dB margin above the CCIR levels should easily allow the array to operate in the presence of the satellites for those declinations for which the required 8 hours of FIGURE 1. Comparison of Flux and Sensitivity Levels
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