Figure 2-48.—AN/SPN-3SA aircraft control approach radar.

This array is a polarizing filter, which ensures that only horizontally polarized energy travels from the horn region. The antenna scans at a rate of 16 rpm and produces an absolute gain of 31 dB at midband. AN/SPN-35A AIRCRAFT CONTROL APPROACH RADAR The AN/SPN-35A (fig 2-48) is a carrier-controlled-approach (CCA) radar set used for precision landing approaches during adverse weather conditions. The radar displays both azimuth and elevation data, which enables the radar operator to direct aircraft along a predetermined glide path and azimuth course line to a transition point approximately 2 miles from the ramp of the flight deck. The azimuth antenna, AS-1292/TPN-8, functions in the azimuth rf line for radiation and reception of X-band rf pulses. The azimuth antenna comprises a truncated paraboloid-type reflector with an offset feedhorn and a polarizer assembly that provides remote-controlled selection of either horizontal or circular polarization. The antenna is located above the azimuth drive assembly on the stabilized yoke. The azimuth drive can rotate the antenna in either 360 degrees or in limited-sector modes of operation in the horizontal plane. Figure 2-48.—AN/SPN-3SA aircraft control approach radar. 2-29