This paper describes the characteristics of the 16-foot diameter millimeter wavelength antenna system at the Electrical Engineering Research Laboratory, University of Texas, Austin, Tex. Aperture efficiencies of the antenna at the frequencies of 35, 70 and 94 Gc are 59 per cent, 55 per cent and 52 per cent, respectively, corresponding to gain and beamwidths of 62.5 dB and

at 35 Gc/s, of 68.5 dB and of 70.9 dB and

at 94 Gc/s. First sidelobes and other sidelobes over the 35- to 94-Gc/s frequency interval are -18 dB and -25 dB, respectively. The 70-Gc/s radiation temperatures of Jupiter and the earth\´s moon have been measured. The brightness temperature of Jupiter was found to be

K and the maximum brightness temperature contour of the moon was

K. Relatively higher emission temperatures were observed from the maria and the craters of Copernicus and Tycho than from surrounding lunar areas.