FROM GOOD TO BAD

Evening Star, Issue 19764, 14 January 1928, Page 12

FROM GOOD TO BAD

RADIO RECEPTION DEGREASING A SUGGESTED EXPLANATION “Why is it we cannot receive Australian and American broadcasts as well as we used to?” That and similar questions prompted an ‘Evening Star ' reporter to seek some information regarding the inability of listen-ers-in to receive radio concerts from afar at the same volume as some five years ago. , , A Dunedin man, who has a depth ol radio knowledge, was interviewed, and expressed himself thus;— “Radio is certainly not what it was some years ago. When I first commenced working a set, that is five years ago, KG’O California could be heard here at good telephone strength, using only one valve, but now the reception of the same station on an eight-valve receiver is rarely worth listening to. That shows that radio is not carrying as it used to. “Australian stations are also aifected in this same way, Two years ago the Australians were all working on a verv. much lower power than at prescut, ‘but they came through a great deal better in Dunedin than now. Many listeners will remember when 4QG Brisbane opened. The concerts then came over equally as well as Wellington is received now. “ My opinion is that the phenomenon is explained in scientists’ theory that the earth travels through a certain cycle in relation to sun spots, it takes about eleven years, we are told, for the earth to complete the cycle, and in 1927-28 the cycle is at its lowest ebb. It is possible that these sunspots are affecting reception, which has been speedily decreasing during the last five years. Whether the conditions will improve after 1928,. of course, remains to be seen.” When asked if he could give any reason for radio signals being much weaker in summertime than ju winter, the radio man said that summer conditions were never as good as winter, because there is more daylight and usually more static. He proposed that daylight be called summertime and night be wintertime so that .the position could’ be the more easily explained. “At night.” lie said, a theoretical or assumed layer of ironised gas forms about fifty to 100 miles above the surface of the earth. This layer acts as a gigantic reflector of radio waves, and makes them follow the contour of the earth. In 1900 Heaviside suggested the existence of this layer, which would reflect the radio waves in much the same way as a ceiling may reflect sound. The Heaviside layer was suggested because of the difficulty of understanding why radio signals should S>e heard over great distances when vaves, when they normally travelled in straight lines, should apparently

have been radiated off into space. It clearly becomes much simpler to understand why signals are heard better at night if all round the earth there is a huge reflecting layer which turns the waves back and compels them to follow a path more or less round the earth. “ The sun is said to dissipate the Heaviside layer so that in the daytime some of the strength from radio stations goes right tip into space and is lost. That is to say, all the waves except the direct one are useless. “ I also think that the Heaviside layer is responsible for stations ‘ mushing,’ as the direct wave and the reflected wave arrive at the set out of harmony.” Ho was also of thp opinion that the sunspots referred to had an effect upon the weather, which, perhaps, accounted for the bad winters experienced during the last two or three years.