• FENN AND RISPIN A Terrestrial Air Link for Evaluating Dual-Polarization Techniques in Satellite Communications A Terrestrial Air Link for Evaluating Dual-Polarization Techniques in Satellite Communications

■ This article describes the radio frequency design and test data for an experimental terrestrial air link, which simulates a satellite-to-ground communications link operating in a dual-polarization frequency-reuse mode in the 17.7-to-21.2-GHz band. The terrestrial air link comprises a transmit site located on Mount Pack Monadnock in Temple, New Hampshire, and a receive site 42.2 km away in Westford, Massachusetts. The transmit site uses a 1.8-m-diameter dish, and the receive site uses an 18.3-m-diameter dish enclosed by a 28.4-m-diameter air-supported radome. The terrestrial air link provides a test bed for evaluating atmospheric effects of fading and scintillation, along with amplitude, phase, and polarization distortion that can compromise the performance of satellite-to-ground communications systems. The test data indicate that the terrestrial air link has a high degree of cross-polarization isolation under clear-air conditions and is well suited for evaluating dualpolarization frequency-reuse techniques. As the information age explodes, so doe