This paper describes the r e s u l t s o f a 140 Mbit/s 64 QAM d i g i t a l microwave radio f i e l d t r i a l t o characterise a space d i v e r s i t y channel model w i t h maximum power combining. Measurements were taken on a 60.8 km overwater route i n New Zealand.To the spectral data collected from the f i e l d t r i a l , a Rumnler type model has been f i t t e d .The pdfs o f the non-diversity and d i v e r s i t y channel model parameters are estimated from the measured data.