The Radio Listener

Dominion, Volume 30, Issue 46, 18 November 1936, Page 15

The Radio Listener

(By

Ether.)

Til ahi’s Mast. , . Work has progressed satisfactorily on the 700i't. mast in course of erection lor the new 2YA at 'i'itahi Bay. Despite delays due to ibe weather, the mast is uow at a height, above ground-level ot over 400 ft. If all goes well aud th e absence of wind permits steady work, there is every prospect of the mast nearing completion by the end of this mouth. Once the mast is up the new station will be well on the way to completion. Lhe groundwork is continuing steadily. It is hoped, in fact, that the first initial tests from the new station will take place during December.. These tests will probably take some little time. The new station. however, will gradually be used lor programme purposes for longer and longer periods, until eventually it will take up its full-time job of transmitting the programmes.

Empire Programme. The Empire station at the moment is a little uncertain in strength. Some nights it is very hard to pick up in the early part of the session. Old hands are aware of the vagaries of the sho'rtwaves, and have Learned patience. New listeners must content themselves with waiting. Possibly, by December 4 the conditions will have improved again. In that case, shortwave listeners who tune to Daventry will have the opportunity of being able to hear a commentary on the first Test in Australia. The transmission will, in fact, have gone round the world completely, being transmitted from Australia to England, thence to New Zealand via Daventry. A similar commentary will be given next day. Those who prefer it can tune to their local station and obtain the commentary direct from Australia via the Tasman.

Followers of the Lloyd George family may care to make a note of the fact that his daughter, Megan, is to speak from the Empire station at 8.45 p.m. on November 27.

Television Service Area. Experts appear to hare been wrong when they predicted that the service area of radio waves used for television would approximate to that of light rays. Tests carried out by an experimenter in England, Mr. M. G. Scroggie, B.Se., A.M.1.E.E., show that this is far from being the case. The wavelength in use was, it is understood, in the vicinity of six metres. Writing in the “Wireless World,” he says:— “The tests were made with a simple super-regenerative receiver having wire ends reaching to floor and non-metallic roof of the car. These were later replaced by a telescopic dipole made from tubuiar camera tripod legs. “Passing through busy streets the reception fluctuated a good deal, and local absorptions were noted, but the severest effects of these were generally confined within limits of a foot or two. Some interference from the ignition systems of passing cars eould ocaesionally be heard, and, of course, the continuous noise of the car in which the receiver was installed (not fitted with suppressors), but this was not bad enough to render speech hard to follow or to mask the background noise generated by the receiver itself. “An open level stretch of road conformed to expectations in giving excellent reception, but even here a periodical extinction or fluctuation was sometimes observed. Mental calculation -based on the speed of the car showed that whenever

this effect was observed it was usually at. intervals of the order of half a wavelength.” -A. somewhat similar effect place when the receiver is stationary and turned so as to obtain a minimum of reception. A vehicle moving past upsets the balanceout of the signal and gives rise to a succession ol maxima and minima. It was found possible to detect even a bicycle at 40 feet, and an aeroplane at. several thousand feet. Strong reception was obtained up to the maximum distance, some miles north of Biggleswade (over 40 miles from the transmitter), where the signal was actually received with the aerial completely telescoped and lying horizontally in the bottom of the ear —the worst possible conditions. There way appreciable screening just beyond the hill (440 feet) near Stevenage, but otherwise little of interest. In general, the strength of reception over the greater part of the distance was such as to render even the ear ignition inaudible. Going to still greater distances, the sound programme was heard quite (strongly and clearly, though with a fair background of super-regenerative noise, indoors about 100 feet above sea-level at Eastbourne. This is sixty-two miles from the transmitter, and no fewer than 3000 feet below the horizon. Not only is there considerable earth curvature intervening, but a direct line passes right over Tatslield, selected by the 8.8. C. for a receiving station by virtue of its altitude. Similar results were obtaiued farther along the south coast at Rye, while out-of-doors, on the top of Beachy Head, the signal was really strong —good enough to suppress all background noise even when unmodulated.

t Radio and Flames. i A group of scientists who have been - experimenting with the effect of Hertzian waves on flames originating through gaseous mixtures, are reported to have made some remarkable discoveries. It is ; stated that under the influence of a five--1 hundred-metre wavelength, an oxygen- * acetylene flame is greatly increased in in--5 tensity, a given quantity of gas being consumed in half the normal time. At 20 > metres the effect disappears entirely, but J reappears at 8.8 metres. The research ; workers attribute this effect to “the agita- • tion of the molecules of the gas by ionisation due to the passage of the waves.” , They do not, however, offer any reason ' for the .phenomenon only occurring at ; certain critical wavelengths. Sailing. On Friday evening IYA listeners are promised an interesting talk by Mr. George Dennes, tho popular president of the Herne Bay Sailing Club. Mr. Dennes, who is one of the leading authorities ' on boating in the north, has chosen as the title for his talk, “The Youth and His Boat.” The talk should be eagerly listened to Iby boating enthusiasts?. Tour Cancelled. Owing to illness in her family, Mrs. C. K. Williams, who was to have toured the national stations ag Kirimamae, has had to cancel her intended visits north ami south of Wellington. .Last Saturday night phe was able to keep her first engagement to perform from 2YA, but all other broadcasts scheduled will not be made.