Abstract
Trials of the Canadian Janet B system were carried out on an auroral zone circuit during July, 1958, and from early in December, 1958, until the middle of April, 1959. The July, 1958, trials, which were performed at frequencies in the vicinity of 40 mc, revealed the vulnerability of the system to polar blackout at these frequencies and to excessive error rates with rapidly fluctuating auroral signals. The objective of the trials carried out between December, 1958, and April, 1959, was the accumulation of long-term statistical data. The test message and operational procedures were designed to permit detailed analysis with an IBM 650 computer. Some preliminary results are included in this paper. Because of the basic importance of the polar blackout problem, pertinent experimental data concerning the major blackout of July, 1959, are presented and discussed.