A broad-band 11 GHz radio propagation experiment

The designer of a digital radio system (DRS) requires quantitative data on flat and frequency-selective fading in order to assess the need for diversity and equalization and also the feasibility of using the same repeater sites developed for systems in the lower bands. Preliminary results from an experiment which measured the statistical distribution of the complex channel response across a 1 GHz bandwidth at 11 GHz on a 36 km path are described. On this test path the cumulative distribution function of signal attenuation due to rain was found to be about an order of magnitude greater than that due to multipath fading. Incuded are typical records of the complex frequency response during frequency selective fading (showing large variations of group delay), joint cumulative distributions of amplitude, amplitude slope, and notch speed.