Fade measurements on the wide bandwidth HF channel

Abstract

This paper presents the results of HF channel fading measurements on 2000 and 3000 km midlatitude paths using a 1‐MHz instantaneous bandwidth direct‐sequence pseudonoise (DSPN) probing signal. The channel impulse response is estimated by correlating the received probe signal with a local DSPN reference. The channel is characterized in terms of the autocovariance and distribution functions of the received power. Bandwidth‐dependent characteristics are obtained by Fourier transforming the measured impulse response and then applying appropriate filtering. The measured long‐term wideband power statistics show a median standard deviation of 2–3 dB and median decorrelation times of 37 to 57 s. Both median fade depth and median incremental fade depth always decrease with increasing bandwidth.