Accession Number : AD0454950


Title :   H.F. PROPAGATION IN THE ARCTIC. CHAPTER 15,


Corporate Author : DEFENCE RESEARCH TELECOMMUNICATIONS ESTABLISHMENT OTTAWA (ONTARIO)


Personal Author(s) : Jull,G W


Report Date : Jan 1964


Pagination or Media Count : 20


Abstract : This paper examines the results of several studies of oblique incidence frequency sounding and 30 Mc/s riometer absorption with the objective of using this information to increase the reliability of HF communications on auroral zone circuits. Studies have been carried out during low and high intensity polar-cap absorption (PCA) events, and moderate and severe geomagnetic storms, to determine the effect of these disturbances on HF transmissions on a number of auroal zone point-to-point circuits and on a circuit from a ground station to an aircraft that was flown into, and through, the auroral zone. It was found that transauroral and a subauroral zone circuit were less affected by polarcap absorption than an inner auroral zone (polarcap) circuit, while the transauroral circuit suffered the greatest deterioration during the main phase of moderately severe geomagnetic storms. Absorption measurements from riometer stations were used to establish that the majority of all occurrences of auroral absorption during certain geomagnetic storms were correlated over north-south distances of less than 900 km. It was confirmed that frequency sounding systems can be used to provide direct assistance to communication systems in the selection of optimum communications routes and operating frequencies during PCA events and geomagnetic storms. In order to match communications operating procedures to the highly variable characteristics of auroral sporadic-E and F-layer propagation during geomagnetic storms, it was found necessary to provide a well-spaced selection of assignments. (Author)


Descriptors :   ARCTIC REGIONS , PROPAGATION , RADIO RECEPTION , HIGH FREQUENCY , ABSORPTION , ATMOSPHERIC SOUNDING , FREQUENCY , RELIABILITY(ELECTRONICS) , POLAR REGIONS , MAGNETIC STORMS , AURORAE , RADIO TRANSMISSION


Distribution Statement : APPROVED FOR PUBLIC RELEASE