Results from a Three-Hop Tropospheric Scatter Link in Norway with Parallel Operations on 900 mc and 2200 mc

A three-hop troposcatter system in Norway with simultaneous operation at 900 mc and 2200 mc is described briefly. From measurements on a 360-km hop in the period October 1957 to June 1958, it is concluded that 1) the monthly amplitude distributions are approximately Gaussian, and the 1-minute amplitude distributions are approximately of the Rayleigh type, 2) the signals are generally considerably stronger (differences up to the order of 10 db) in summer than in winter, 3) the monthly median strength of the 900-mc signals is generally 0-2 db stronger than that of the 2200-mc signals, 4) the foreground conditions may be critical, 5) the 1-minute fade duration distributions are approximately log-normal, 6) there are indications that the normalized 1-minute fade duration distributions are about equal for 900 mc and 2200 mc, 7) considerable reductions in telegraph error rate are effected by increasing orders of diversity reception, 8) the telegraph error rates are equal for 900-mc and 2200-mc signals of equal median strengths, 9) frequency-modulated telegraph multiplex equipment is slightly superior to two-tone telegraph multiplex equipment, when adjusted to equal loadings, 10) antenna radiation diagrams depend critically on local surroundings, such as woods.