FOR THE REAL BEGINNER

Evening Post, Volume CVII, Issue 22, 26 January 1924, Page 22

FOR THE REAL BEGINNER

STARTING WITH A CHEAP SET.

The complaint has been made, and perhaps justly, that the matter usually published about wireless caters for the experienced and leaves the absolute beginner uncared for. In case this is read by someone who is flirting with the idea of starting the new hobby, the writer proposes to. try. to "push him off the bank," with every expectation that once he gets the feel-of the water he will not be satisfied till he can swim anywhere. There is no doubt that those who once tackle wireless find it the most fascinating of hobbies. The beginner, caa begin in many ways. If he has plenty of cash, he can thoroughly enjoy himself with a career of buying, and for such fortunate individuals the best guidance is easily availablo in a variety of text-books and in expert advice. But probably/ the majority of those for whom this Is written must acquire their gear by degrees, and sacnficially. Th,e writer has a special regard for young beginners who take their hobby seriously, and takes the opportunity of urging that theory should not be regarded as either Superfluous or, a bore. Whatever immediate satisfaction there may be in getting excellent results without knowing how it is done, there is* no personal credit to be got from merely buying a n expensive set, or :from buying a complete outfit of , parts and putting them together in strict compliance with, a standard set of drawings. Such a set, if it is'mechanically perfect, is bound to work. ..There is excellent entertainment to be had from that form of the pastime; but the best pleasures '. are . reserved for the real "amateur," who, even if he buys instead of constructing, has gone to the trouble of finding out how and why. He may bore some of his friends with incomprehensible taxk about electrons .and grid bias, and so on, but he will never bore himself.

Undoubtedly the best way for the real beginner to begin is to get some wire and make a crystal set. Practically the only'considerable expense to begin with is the telephone receivers, which will cost from 30s upwards; according to make. A pair of receivers of good make will last a lifetime, and the judicious beginner will not be mean with himself. Some unscrupulous people have tried to get receivers cheaply by robbing the telephone 'System, only to find that they are almost useless for wireless work. The telephones used for wireless are the so-called "high resistance" type. They have windings' of a very large number of turns of fine wire. There is no value whatever in the resistance, which is merely the result of the length of wire used, "and a better term, occaionally used, is "-high impedance," the > exact meaning of which will dawn on the beginner after he has studied the subject for sometime. , Apart from the telephones, the initial Expenditure need be a matter of a few shillings only. „ About 100 or 150 feet of wire for an aerial will be needed, with suitable insulators to support it. The length of the aerial is quite uniiriport- ' ant, so long as it is somewhere between 50 feet and 200 feet, although neither extreme is advisable.' There is no. legal restriction whatever. If there is room, a horizontal wire about 100 feet long is very satisfactory. Frqm one end of this, a " down lead " should be brought to the set. Alternatively this connection may be made to the middle of the suspended wire, and if it is a separate wire, the joint with the aerial should be soldered. Plain copper wire of about 14 gauge is satisfactory. A slight gain may result from using stranded wire. The aerial may be supported on special masts, or between convenient building, or fastened to a tree, but if a tree is used, precautions must be taken to avoid the wire being broken down when the tree' sways in the wind. In any ca3e, the aerial must be supported by means of insulation,' and no part of the aerial itself must gome into contact with anything else. The down lead must be insulated where it enters the operat-ing-room, by means of a suitable porcelain tube or some other means. The height of the aerial is as much a - matter of convenience as- its ( length. .Ihe simple rule is to make it as high as possible. If on 6, is using a valve set, height becomes still less important; but the longer and higher an aerial is (within limits) the louder the results will be with a crystal set. The whole aerial equipment can be put up m style for about 10s, if readymade supports are available. Masts are apt to run into money, but need not cost much if they are kept of reasonable Jieaght. It is wonderful what can be done with a stick 12ft high. Those who have read much abont crystal reception of broadcast programmes should.remember that the 25-mile range wtuch is. often mentioned1 is not likely to be achieved' in Wellington at present, rhe effective use of crystals at such a distance requires powerful broadcas.ting, and the local stations are using only-15 watts, as against 500 as a recognised standard. At seven or eight miles, therefore, the music is very faint. But it is very satisfactory within two or three miles, and no doubt before long much higher power will be used. Details will be given later for the installation of the receiver.