YOUR OWN WIRELESS

Waikato Times, Volume 96, Issue 15033, 2 September 1922, Page 14 (Supplement)

YOUR OWN WIRELESS

HOW TO START, A SIMPLE THING THAT ANY BOY CAN DO. • LISTENING TO THE VOICES IN . SPACE. Fixlna the Aerial. Having obtained a permit, you must rig up an aerial —the wire which is to catch the messages as they travel across the land. The possible length and height of this wire will be given in your conditions. Subject to these limits, you must make the aerial as long, and as high above the ground, as possible. No doubt you will be able to find some convenient flagstaff, tree, or chimney to take one end, while the other end might be taken to a staple high up on the wall of the house.. The wire must be insulated from its supports by some non-con-ductor of electricity. If you are unable to arrange a very long wire, you will get better results by using two wires, which must be separated by spreaders, about six or eight feet long. The wire connection from the aerial to the apparatus should be made from the end which is nearest the wireless room. The connection must be soldered to ( the aerial. In the case of two wires, two down-leads must be taken, one from each wire, and joined together just befere they enter the wireless room. Tuning Up to the Wave-Length.

They must, of course, he insulated at their entry by passing them through an insulating tube in the wall. Suitable wire and insulators can be bought quite - cheaply from your dealer, who will probably be pleased to advise you. Before buying wire, measure up for your’ aerial with string, and then buy a few yards more than you appear to reed. A beginrer will do well to be content with a set which will receive wireless waves ranging/ in length from about 200 metres to 2600 metres (one metre is, roughly, 3ft 3in). This range wilt allow for tuning up to the wave-length used by the ships, 600 metres. Music and speech broadcasted by wireless telephony may be heard on the shorter waves, between 350 and 425 metres in length. The Wire to the Earth. If you do not know much about wireless, you had belter tell your dealer, and get him to help you. Ask for a crystal detector set of the range indicated above, and get him to show you where to connect the aerial wire to it.

Then you will need to know how to tunc. This is simple, and if you tell your dealer the size of your aerial he will he able roughly to show you the adjustments of the various handles when the set is tuned for ships. But you will find out a great deal by experiment. One of the terminals on the set will have to be connected to the earth. Take the wire to a large metal plate—a big sheet of galvanised iron or of wire netting would do—buried in the earth near the house, so that the wire to the earth is as short as possible. Failing an earlhplate, solder the earth connection to the nearest gas or water pipe. There is no danger if you are quick in doing it.

The best type of crystal is carborundum. It is very robust, and not easily put’ out of order. Olliers are more sensitive, however, though not to a remarkable degree.- J'lie upkeep of a crystal receiver should not be morc'Uian five shillings a year.It is only fair to give the following warning. Wireless as a hobby needs skill and knowledge. A set cannot be built blindly or worked mechanically, like a model aeroplane made up from ready-made parts. The telephony concerts may be “picked up” and enjoyed without special skill, but by far the greater part of wireless work is telegrnnhic, and there is but little fun to bn got out of il unless you can read the Morse signals. Three or four pounds is as much as should be paid for such a set ns is referred to, but this does not include the price of the necessary pair of telephones. Tho Simplest Wireless Set.

Aerial.—This should be of fairly stout copper wire. Insulators.—Glazed porcelain insulators are. bcsl.

Spreaders. —These are needed if the aerial consists of two wires, and should be of bamboo, six to eight feet long.

Deceiving Set.—Crystal detector and simple receiving circuit, to tune from 200 metres to 2000 metres.

Crystal.-— Carborundum, This is robust and easily adjusted. Keep one spare crystal as a stand-by. Dry Cells. —For carborundum you will need about two and a-half volts. Telephones.—Get, one pair of high resistance telephones. It will then he unnecessary to have a telephone transformer, which is expensive. Earth Plate.—lron or zinc sheet, or wire nettinff. Bury in moist earth two feet down-