Ka-band propagation measurements from the Advanced Communications Technology Satellite (ACTS)

In September 1993, the NASA Advanced Communications Technology Satellite (ACTS) was deployed into stationary orbit, near 100°W longitude by the Space Shuttle Discovery. ACTS supports both communication and propagation experiments using two beacons, one at 20.185 GHz and another at 27.505 GHz, where rain attenuation and tropospheric scintillations will significantly affect new technologies proposed for this spectrum. Heavy rain at Ka-band can easily produce 20 dB of attenuation along the propagation path. Beacon attenuation and attenuation derived from radiometric sky noise brightness temperatures are presented from early 1994. Concurrent polarimetric weather radar measurements are shown to characterize the attenuation not only from rain, but melting, wet snow