ABOUT WIRELESS

Nelson Evening Mail, Volume LVI, 29 August 1923, Page 8

ABOUT WIRELESS

SOME MISAPPREHENSIONS

NOT AS SIMPLE AS IT SOUNDS

Electricity is still a puzzle to the scientists, although they can do such wonders with it, so that we cannot be surprised that the ideas of the ordinary citizen on the subject are decidedly hazy. Jlow many persons could really explain intelligently the common telephone- an instrument most of us use a dozen times a day? And now that wireless telegraphy and telephony have come along the ordinary citizen’s ideas on the subject of communication by the aid of electricity are even more woolly than ever. When people (says the Star) read that tin Auckland school boy with a homemade apparatus, using no more power than would be sufficient to light, the tan lamp of a motor car can maintain communication with a ship somewhere off Dunedin, they sav, “My, how simple; r thought wireless was most intricate ! There is, up Ponsonby way, a young fellow with a mechanical bent very strongly developed, who, at the cost of a few shillings, “knocked tip’’ a crystal set with which he has no end of fun, and every morning, after spending his evenings in a little box-looking shed with those ear-pieces strapped on his bead, lie is as entertaining as a tame mahatma —be seems to have been talking, or rather listening to people all over the place. In fact, be reminds you of nothing so much as the man in the Arabian Nights story who possessed the magic carpet that transported him here, there, and everywhere in the twinkling of an eve.

When some of the grown-ups hear tlm 1)0vs, bitten by the wireless craze, talking about their hobby, and see the cheap and simple apparatus that has been rigged up in the washhouse, or perhaps in a bedroom, and hear next morning at breakfast what Awanui station sounded like, what sort of note the Sydney boathad, and so on, these old people are apt to imagine that wireless is a much simpler thing than it is. It- is quite true that remarkably clear signals can be obtained by the novice on a very simple set, but there is a vast difference between transmission and reception. However, wireless telephony, and not telegraphy, forms the basis on which most of the popular errors are founded. It, too, can be picked up on

very simple apparatus, provided that the receiver is within a short distance of the transmitting station. If reception is carried out with a simple crystal type of receiver over a distance of twentyfive miles, then very satisfactory results have been achieved. For longer distances the use of the thermionic valve for reception is necessary, and as the distance increases more than one valve is needed. And here is where the difficulty lies. Reception with a circuit utilising thermionic valves requires technical knowledge. “Tuning” so as to bring in ’distant stations is a delicate operation. The commercial wireless operator is not only a man who has a thorough knowledge of the Morse code, but he is also in possession of technical knowledge, understanding why his apparatus is arranged in a certain manner, what he must adjust to obtain certain results, and just how tie must handle his receiver in or-

der to hear signals over some distances. When receiving apparatus is close to a sending station messages may be received even though the tuning be faulty, the

power at the transmitter being high enough to overcome the effects produced by incorrect tuning or mis-tuning. Luck is not (lie case over long distances. It inay be said that success in wireless depends upon the transmitter and the receiver. This may sound paradoxical, but nevertheless it is true. To enable all classes of receivers over a given area to hear telephony a certain power must be used, and if a receiver is to operate over large distances, its construction must be perfect. Long distance transmission lias certainly been effected over large distances on low power, but while perhaps one station managed to pick up the messages, probably hundreds of others did not. If then, a service of wireless telephony which will prove of benefit over large areas is to be instituted, then it must be more than a low-

powered station, and in this fact lies the chief obstacle. The cosipf an up-to-dat*e and efficient station would run into many thousands of pounds and it is obvious that at the present time such figures would prevent it being used in a general way. Again, the cost of a delicately-constructed receiver, while not altogether high, is by no means low. Wireless telephony and telegraphy comprise wonderful inventions, hut the ideas held hv many people regarding their practical application to everyday life in the immediate present arc to say the least mistaken ideas.