Abstract :
During the last eighteen months the Naval Research Laboratory has made a very large number of measurements on skip distances in the frequency band between 30,000 and 40,000 kc. Most of the measurements have been taken during the month of January, February, and March, 1929, and the corresponding months of 1930. Since the measurements for the two succeeding years are substantially in agreement we believe it worth while to report them at the present time even though they are based largely on measurements made in a general southerly or southwesterly direction. A large number of different frequencies have been used in this band, most of the data being based on two-way communications. The experiments have naturally been restricted to the daylight hours. A table of results of midday skip distance in nautical miles over the range of 20,000 - 40,ooo kc is provided. It may be mentioned in conclusion that a good many observations made on harmonics from high power, high-frequency stations in the 10,000-kc to 20,000-kc band have been used to check in with the other measurements and so far have been found to be in very fair agreement therewith.
