WIRELESS NEWS.

Press, Volume LXII, Issue 18722, 19 June 1926, Page 8

WIRELESS NEWS.

RADIO SIGNALS.

ATMOSPHERIC CONDITIONS.

(specially warms' toe the pbess.)

(By "Electra.")

Theories relative to the influences of the atmosphere upon radio transmission are almost as numerous as there are individuals studying the problem. About the only unanimity of opinion is the fact that the atmosphere does exert an influence. There is agreement also upon the.existence of static, but not as to its cause. We know how to overcome static annoyances to some degree, through the use of high power broadcasting stations, but it hardly represents a solution to the problem. It is not unlike our ability to relieve a disease, but failing to effect a permanent cure because of our ignorance of the fundamental causes of the disease.

' There is also general accord with respect to the occurrence of more frequent atmospheric disturbances during the summer than during the winter, and also more intensive disturbances. Une may receive messages quite as clearly during the summer time as during the winter, but not from such great distances. . . iae common reason given lor the greater success in transmission in winter over summe r is the iewer hours of sunshine and consequent reduced ionization of the air. However experimenters have received message's on a day of brilliant summer sunshine as good as on any winter day. Again, the phenomenon of lading has heen variously interpreted. Some hud it increases at night, while others claim it to be greatest during the day. We all know from experience that on somo days it is more noticeable than on others; or again, on the other hand, it may be absent entirely. V arious explanations have been offered, scientific and otherwise, for the fading phenomenon. The Heaviside Layer theory, advanced some years ago, has received favourable attention, but lias not been as yet accepted. This involves the idea of a layer of air m the upper atmosphere with a density different from that below it, and thus constituting a reflecting surface, which may, or may not, retard the wave process, depending upon the strength ot the wave.itself, the condition of the atmosphere in the direction of the transmission. On ,the other hand, there are those who attribute the interruption of the progress of these radio waves to the solid portion of the earth. It is quite apparent that while we are making some progress, we are still floundering around, 'as it were, in the sea of experimentation. An opportunity to contribute to the progress.of -rad» transmission and consequently to the progress of civilisation still awaits everyone interested in radio from the experimental point-of view.

Observations In U.S.A. Eugene Van Clee of .the Ohio State University, U.5.A.,. has earned out a series of observations for about a year, using a five-valve selective noutrodyne set m an effort to determine something of the relations between the weather arid radio waves. It occurred to him that it was not so milch a matter.ot local weather which affected the transmission as' it was the larger elements inducing the particular kind of weather. In other words, the weather which we have at any given place in the intermediate latitude is the result of a general movement of cvclones ana anti-cyclones, . and the thought *as that these pressure areas rather than local weather affected transmission. Now, it so happens that the observations made by Van Cleef reveal' a seemingly definite relation between the pressure of the atmosphere and ' the strength and clarity of radio reception. - , ~ A The observations seem to show that the more nearly the radio waves cross isobars at right angles the clearer and stronger is the reception. They show at the same time that the moisture content of the air is not always an influential factor, for in many instances the reception is quite as good in a very humid atmosphere as in,a very dry one. It seems that the moisture content of the air may be a factor when the atmosphere is highly electrically charged. Some observers maintain that the barometic conditions have no _ efEect upon the audibility of radio signals. This conclusion, however, is open to considerable challenge,'and here arises a large opportunity for observers everywhere in the .country. If it were possible to gather a sufficient amount of data for listeners all over Australasia, who" will take the pains to record the strength and clarity of reception from given stations on successive nights, making certain that their receiving set is not alterec 1 . in any way while the tests are oh, it would be possible in a relatively short period of time to correlate these returns with a baromic chart and arrive at pretty definite conclusions as to the influence of air pressure upon radio transmission. If some central agency would be willing to receive a series of observations like thoso suggested and would correlate, them, both the agency and the observers would make* a great contribution to the radio world and the genoral public. The observations which ought to be made are temperature, the state of the weather that is, whether it is "raining, . clear, cloudy, foggy, or snowing—the baromic pressure and, if possible, the outdoor relative humidity of the air. As for the received signals we should know whether they come in strong, moderate, or weak, and from what station the message is being received. Comparing Results. It is best to select nearby stations and. one or two distant ones that are fairly easy to hear on a normal night and make the observations with regard to these stations rather regularly. This is better than to attempt to make a record for a dozen different stations. If a barometer is not convenient or an instrument for determinine tho relative humidity is not available, then the first observation can be omitted and the relative humidity for the out-of-doors may be estimated in terms of one's feelings—namely, whether the at[mosphere seems dry or fairly humid. I Another aspect appears of almost equal importance with the determination of the influence of the weather upon the transmision ofs radio waves, "iliis concerns the possibility of learning more about the atmosphere itself. If we can work out the effect of the atmosphere upon radio, then perhaps this in turn will give us a clue to an understanding of the circulation of the ; air in our cyclones and anticlones. Tlie necessary effort on the- part of an individual observer is really quite small, but the sum total may contribute toward a tremendous step forward in their. understanding -.of the weather. Her© is an opportunity to accomplish, two purposes at once. On the • one hand, to enable us eventually to effectively transmit radio messages under any weather conditions, and on the other hand to increase our knowledge of the causes of variability in our weather.

NOTES. To-night, if arrangements are completed, a programme of dance music from the Dix Sand, cabaret in Cathe-

dral square will be relayed through 3AC The treasurer of the R.S.C. (Mr. H. V. P. Brown) has recently moved his quarters and is re-desigriing his transmitting station. . . Mr H. Clayton, late of Thames, and now of this City, has started another transmiter under the call sign of 3AG. Though he has only been going a short time, he has done some very good work. Mr Clayton's name is still attached to the. weil known amateur, station, IAK.