WIRELESS.

Waimate Daily Advertiser, Volume XXIV, 21 March 1924, Page 6

WIRELESS.

A CHEAP TRANSMITTER. It is a very unfortunate fact that there is only one transmitter in Invercargill at present (says a writer in the Southland Times), although we shall have at least one more soon. Most radijy “fiends” look on a transmitter with awe, and think that the cost of its construction is far beyond their means. It is time that mistake is corrected.

Of course, most owners of valve sets know (alas, Iqo well!) that by means of a key in the circuit they can transmit over short distances. What they do not seem to know, however, is that with a Ford coil and key they can make their receiver into a transmitter capable of working over most of the South Island.

The chief drawback to a transmitter is the need of a suitable hightension supply. The use of a Ford coil solves this difficulty, as no one dould call it expensive, All the apparatus required is:—An inductance, consisting of 45 turns of 18 or 20 D.C.C. wire on a 5 inch tube, tapped every five turns; a small variable condenser, about .0005 MFd. preferably with wide spacing; a hard valve, e.g., a French “R” with, of course, rheostat and socket; and a grid, a condenser, with mica dielectric. M|>st of this can usually be discovered where any self-respecting “ham” has his set.

As the full voltage of the Lizzie is too great for the valve a condenser must be connected across the secondary.

This can be done from six glass quarter plates with sheets 'of tinfoil between.

A Grade 2 license is necessary to operate this set. Several Northern “hams” are using this type of set, notably IAC. and 3AD. 3AD has worked most of the South Island and some of the orth from Greymouth, and has a clear, steady note.

Come on, y|ou chaps! Get your op’s. ticket and a spark coil ICW transmitter. Think of the fun of yarning to your brother “hams” up North!