RADIO AND ITS RECEIVERS

Sun (Auckland), Volume III, Issue 675, 29 May 1929, Page 16

RADIO AND ITS RECEIVERS

Conducted for THE SUN by

R. F. HAYCOCK.

REPORTS WANTED

SHORT WAVE STATIONS The short wave station at Bandoeing. Java, will be relayingstation PHI on 37.5 metres on May 23 and 30 from 11.30 p.m. to 1.30 a.m., New Zealand time. Station PHI transmits on 16. SS metres on Wednesdays and Saturdays from 11.30 p.m. to 3.30 a.m., and on Thursdays from 10.30 p.m. to 2.30 a.m., all times being for reception in the Dominion. Reports from any listeners picking up either the main station or the relay will be appreciated.

TO THE MOON AND BACK RADIO ECHOES LEAVE EARTH Observations of considerable importance in indicating the nature of the medium through which wireless signals are transmitted have recently been made in Europe, and are being extended. The observations followed a statement that a distinct' echo had been heard to the signals from the Dutch short-wave broadcasting station PCJF. Careful experiments were made, and it was found that an echo of signals was actually occurring. It was also feund possible to measure the time between the signal and the echo, and the results showed that it occurred up to several seconds after the actual signal had ceased. Since the velocity of a wireless wave is known, it was possible to show that the impulse which had caused the echo signal travelled over distances of up to more than half a million miles between the time of its origin at the transmitting station and the time it was picked up on the receiving station a few hundred miles away. In other words, it must have left the surface of the earth, travelled into space for at least a quarter of a million miles —roughly the distance of the moon from the earth —and then returned to earth again to affect the receiver. .

It was also found that the echoes occurred at varying times after the original signal, showing that the reflection back of the’ wave occurred in space at varying distances from the aerial. At present the results are quite unexplained, but since they indicate the existence in free space of media capable of acting as wireless reflectors, they may shortly yield valuable information.

WIRELESS AND TALKIES i The simultaneous development of ! the home cinematograph projector and talking moving picture apparatus has opened the way for an interesting combination of broadcasting with moving pictures. Following the perfection in Great Britain of apparatus for taking talking pictures by means of home cinematograph cameras, experiments have been begun for the purpose of combining home cinematograph films with broadcasting services, so that the I films can “talk.” | The main object of the experiments I is to devise a way in which films can be produced of operas and other musical productions, so that when these pieces are produced by wireless the owner of a combined wireless set and cinematograph projector can synchronise the music with the picture, and thus see, as well as hear, the production. It is stated that considerable success has already been achieved in preliminary experiments. The only problem to be solved is that of keeping the music and the picture in synchronism, and this can be done by sending a timing impulse over the wireless circuit so that several times a minute the cinematograph projector, which is normally run slightly faster than is necessary for the speed of broadcasting, is slowed down and kept in synchronism.

This principle is used in synchronising the reproducing drum on picture transmitters with the transmitting drum, and it has given perfect satisfaction for this purpose.

RADIO HELPS COOKS

When the 8.8. C. started morning talks for women from Daventry SXX no idea could be formed as to the number of listeners —Women who could spare the time from housework to listen. Some cheese recipes, which were broadcast every morning recently, have proved a useful guide. There were 5,889 applications for the recipes. They came from all parts of Great Britain and Ireland, the Channel Isles and the Isle of Man, Holland, France and Belgium. The penetrative influence of wireless is shown by the fact that the applications included some from such remote places as Hawes (Yorkshire), Grasmere (Westmorland), Croyde Bay (Devon) and Towyn (North Wales).