WIRELESS IN THE ARCTIC

Otago Daily Times, Issue 21733, 26 August 1932, Page 10

WIRELESS IN THE ARCTIC

BRITISH RESEARCH PARTY NEW ZEALANDER’S LONELY VIGIL (From Our. Own Correspondent.) LONDON, July 15. A party set out for the Arctic regions a week ago to try and solve the riddle of why wireless signals fade. They will make their headquarters at Tromso, a small town in the extreme north of Norway, and one of their number will be stationed on a small island 12 miles off the coast.

The man who is to keep this lonely vigil is a New Zealander, Mr W. C. Brown. ITe was born in Dannevirke, and joined the Post Oflicc. Just before the

war he transferred to the Australian Amalgamated Wireless Company, and during the first part of the war was stationed at Singapore. Then in 1917 he got a commission in the Air Force ns wireless observer. After the war he eyas in Wellington for six years, and for some years he has been at Ditton Park Radio .Research Station. His appointment to the expedition is due to the fact that he is assistant to Professor E. V. Appleton, who-is in charge.

\This is the first British Government’s wireless expedition to polar regions. It is sponsored 6y the Department of Scientific and Industrial Research. Tromso is five degrees more north than the most northerly point in Iceland. The intention is to make a full investigation of the upper atmosphere there, using the methods which have proved so successful for work of this character in temperate latitudes. In this work wifeless waves, projected vertically upwards, have been used for probing the air levels from 50 miles to 200 miles above the earth’s surface. The wireless waves are reflected back by the upper atmospheric electricity, and by timing the duration of the journey and by observing the characteristics of the waves on their return to the ground it is possible to deduce the density of the electrification and the way in which it is stratified. Experiments on these lines have shown that the electricity is distributed chiefly in two layers. ELECTRIFICATION OF UPPER LAYERS. The lower of these layers, situated at a height of about GO miles above the ground, known as the Kennelly-Heaviside layer, is the layer that reflects the long and medium wave-lengths and causes the fading of signals in broadcast reception. The upper or .Appleton layer reflects short waves such as are used in beam transmission. Up till now the properties of these layers, as expressed by their daily and seasonal variations of density, have been mapped out only in temperate regions. It has been found that the electrification in them is restored every day by the action of the .sun. During the night it steadily disappears. At present it' is- only possible to speculate concerning the nature of the solar radiation which causes the daytime replenishment of the electricity. The evidence at present is in favour of Professor S. Chapman’s theory that ultra-violet light causes the electrification of the upper layer and high-speed particles the electrification of the lower one.

Experiments at a site within the Arctic circle should throw light on the questions whether the electrical structure of the upper atmosphere is the same in Arctic regions as in temperate regions; and whether there is any connection between the aurora and the KennellyHeaviside layer.