Tests conducted over highly reflective terrain at 4,000, 6,000, and 11,000 megacycles

During the past 10 years the American Telephone and Telegraph Company has conducted tests at 4,000 mc (megacycles) over most major microwave radio relay routes prior to the initial installations. As the necessity for further expansion arises, it is planned to add 6,000-mc and, possibly, 11,000-mc circuits to the existing routes. For this reason antenna height versus path loss tests were performed over four paths with highly reflective terrain in Colorado and Wyoming. The purpose of these tests was to collect information to permit the evaluation of performance at the higher frequencies on existing paths from the results of earlier 4,000-mc tests when a common antenna is used for all frequencies. To obtain comparable results simultaneous measurements were made at 3,950 and 6,310 as well as 3,950 and 11,200 mc. The 3,950-mc measurements were used for reference purposes.