UHF/VHF air-to-air propagation measurements

This paper presents results of air-to-air channel measurements at a center frequency of 250 MHz. Using a test signal of 20 MHz bandwidth, a large number of channel transfer functions was recorded and propagation characteristics evaluated in terms of power delay profile, Doppler power profile, delay spread and Doppler spread. According to the results, the channel might be approximated by a two-path channel impulse response whose parameters depend on the aircraft altitudes and on the type of overflown terrain.