Propagation of Wide-Band Signals at VHF/UHF

The experimental jam-resistant secure voice communications (JRSVC) system developed by M.I.T. Lincoln Laboratory was used to conduct a series of VHF/UHF (225-400 MHz) propagation measurements, representative of a veriety of tactical communications situations, both ground to ground and ground to low-flying aircraft. Results are unusual in two regards: they were made with the receiver in motion, covering many contiguous propagation paths, and the JRSVC system, by frequency-hopping over almost an octave and averaging the results, largely eliminated the effects of frequency-selective (multipath) fading that generally dominate VHF/UHF propagation measurements.