Sun Spots and Short Waves

New Zealand Listener, Volume 20, Issue 517, 20 May 1949, Page 6

Sun Spots and Short Waves

HEN the All Blacks are performing on the sunbaked or mud-caked Rugby grounds of South Africa, from May 31 to September 17 (inclusive), many thousands of New Zealanders at home will be deeply attached to their radio receiving-sets. Results of and commentaries on the 24 matches, including the four Tests, will be followed avidly; and if the post- "mortem examinations that inevitably follow New Zealand sport have a ‘slightly depressing effect on production per man-hour, statisticians may find comfort in the thought that the All Blacks don’t tour every year. While the selectors of the team were discussing the merits of this player and that, engineers of the NZBS were also deeply (if more objectively) concerned with the tour. Their problem was radio reception of news about the team’s progress in the Union. Ever since last October they have been making tests at Quartz Hill (Makara) with the object of finding the best frequencies to use, and something about the reception listeners can expect. By accepting the invitation to go to South Africa, the 1949 All Blacks have raised one or two points of peculiar scientific interest to radio experts. Nor- mally the receiving station of the NZBS at Makara takes short-wave broadcasts from England, Canada, India, and Australia without difficulty; but in the case of South Africa, the line of communication cuts through ‘the southern auroral zone-and not once, but twice (see map on page 7). The engineers’ task has been not only to find the channel offering

the least possible interruption from auroral phenomena, but also to find means of escaping as far as possible the effects of sunspot activity which, at peak periods, so disturbs the ionosphere in or near the auroral zone that transmission by radio is virtually impossible, The two auroral zones circle the geomagnetic poles, and in these areas auroras are visible almost every night, in the shape of rays, bands, curtains, draperies, coronas and diffuse glows. Sunspot activity increases their boundaries, and however attractive the display may be to an observer, the radio engineer views them with distaste. The sun’s activity is not constant, but varies erratically from day to day, though, broadly speaking, in cycles which, from minimum. -through maximum to minimum activity again, last eleven years or so. Conditions of overseas broadcasting, therefore, vary according to the prevailing degree of sunspot activity. The main part of the radio testing work has been to keep a check on the accuracy of ionospherical frequency predictions; and so to gauge how clear a circuit can be expected for the transmission of All Black news. There has been nothing haphazard about these tests. They are carried out with meticulous care and will continue right up to the time of the first match of the tour. Already enough information has been collected to enable the engineers to say that while the circuit of approximately 7,500 miles may not be first-class-that is, of- the quality of the 6.0 p.m. news from London, or a broadcast such as the Melbourne Cup-it should be sufficiently clear to make most of the broadcasting understandable. —

The circuit to and from South Africa is a difficult one, and one that has not been attempted on a regular basis before, although amateur transmitters are sometimes able to communicate with the Union. By way of illustration it may be explained that when communication by tadio-telephone is poor, subscribers can be advised to wait for an improvement in conditions-and that inconveniences two or three people at the most. But what the NZBS proposes to do is to give the Rugby broadcasts to listeners regularly on a pre-determined basis. At both ends of the line of com-munication-Pretoria and Wellingtonspecial directional aerials have been erected for the occasion, through the cooperation of the South African Broadcasting Corporation, the South African Post Office, and the NZBS. The South African Post Office has made transmitters available in Pretoria, and commentaries by the NZBS sports commentator (Winston McCarthy) will be relayed from the football field to Pretoria and then directed to New Zealarid by shortwave. ‘Tape-recorders will also be used for summaries and sent to New Zealand by air mail. The relays direct from the ground will be broadcast simultaneously in South Africa and New Zealand. However the auroral zones decide to behave between May and September next, or whatever outbursts of capriciousness the sun may indulge in, the All Blacks may be depended upon to keep at least one foot on the ground, and the NZBS to give the vast concourse of New Zealand Rugby fans the best reception it can under what may be difficult conditions. me a re ee ee en mmm