Background

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When a meteoroid enters the Earth’s atmosphere the particle is heated by friction with the molecules of the upper atmosphere. The tremendous heat generated may result in a visible streak of light, recognised as a meteor, or shooting star. There is also a trail of ionisation left in the upper atmosphere. This trail may persist for a period of less than a second to several minutes. It is reflections from the ionisation trail, which makes detection of radio meteors possible.

The earliest studies of reflections from ionised layers in the upper atmosphere date from the work of Appleton and Barnett (1925) in England, and Briet and Tuve (1926) in the United States. In the subsequent years a number of investigators remarked on some unusual night time echoes from a region approximately 100km above the Earth’s surface. Previous work had shown that Solar activity could be responsible for such layers during the day, but it seemed unlikely that this could account for these effects during the night. By the end of 1939 it was certain that meteors were certainly a factor to be considered in radio propagation.

The outbreak of war postponed much fundamental research on radio wave propagation, but the development of radar systems, intended for the detection of aircraft and shipping, lead to a wealth of experience in the field. At the end of war many wartime radar systems were used for a systematic study of meteor reflections.

Shortly after the war A. C. B. Lovell established the Jodrell Bank Experimental Station of the University of Manchester. In the early days of Jodrell Bank meteor research was the mainstay of the programme. Jodrell Bank continues to be at the forefront of radio astronomy work today, but is no longer active in meteor studies.

 It was the Giacobini-Zinner meteor storm, of the night of the 9th - 10th October 1946, which captured the public imagination and led to increased interest in meteor study.

In July 1947 QST magazine published an article by an American radio amateur, Oswald G Villard Jr entitled ‘Meteor Detection by Amateur Radio’ introducing the growing numbers of radio amateurs to the phenomena. Prior to the publication of this groundbreaking article, study of meteor scatter had been largely restricted to the professional scientific and engineering communities.

During the 1950s there was a great deal of work to investigate meteor scatter propagation for long distance communication use. More recently, with the advent of artificial satellite technology, meteor scatter communications has fallen from favour.

 With the availability of cheap and readily available computers amateur astronomers began to use radio meteor forward-scatter as a means of measuring meteor activity. Today there is a small but growing number of dedicated amateurs active in this field.