Charles D. Horton

There is something mysterious about wireless telegraphy. It appears to the uninitiated as a magical art; a science unfathomable except to a few whose researches have given them understanding not shared by the average student.

Amateurs in years past have found in the telegraph and the telephone an unlimited amount of pleasure. The construction of transmitter and receivers, the building of the line from house to house, and the subsequent operation of the outfit is bright in the memory of hundreds who now hold responsible positions in the electrical business world.

Not long ago a prominent electrical contractor, becoming reminiscent of his amateur days, said to me, " In my boyhood days we cherished the hope of becoming high in the ranks. We wrote E. E. after our names in the school text-books, and printed letter heads on small hand presses, upon which to correspond with each other. We constructed telephones, both acoustic and electric, and strung telegraph lines across nearly every street in town. But as I think over the past, I realize the immense amount of fun we youngsters lost because wireless telegraphy had not come into existence.

I believe every young man should study the subject and make all the experiments his means will allow. For the young man who takes the study seriously there is a bright future. There is no questiou but what it is the coming thing, and how soon it will be established universally depends upon the energies of the young men of today. "

An amateur outfit of wireless telegraphy in the country or city, should prove a source of much pleasure and profit during the coming months. It is not as expensive as wire telegraphy, which requires relays, sounders and other apparatus, together with wire, which is a leading and heavy expense if a line of any length is constructed.

For a distance of a mile or two no elaborate apparatus is needed, as the sending end comprises a simple key, a few dry cells and a small spark coil, giving about a half-inch spark. The receiving end requires only the purchase of a telephone receiver and a few incidentals, such as a stock of carbon and a few steel needles, etc.

Amateurs may find a detailed description of small coils suitable for wireless sending in back numbers of Amateur Work, and bearing in mind that for short distances of a mile or so a large spark is not a requirement, the expense of construction may be cut down to a very small amount. A spark of one half-inch will serve admirably if care is taken in constructing the receiving end.

In recent experiments I have made over short distances, I have not noted any marked degree of superi-ority where aerial wires have been carried to extreme heights. I found that a small length of magnet wire, supported on porcelain knobs, from peak of house to the first floor, sufficed for the aerial wire, and for a ground plate I drove several long iron rods into the moist earth and connected same together at the tops. I purchased my key of a telegraph supply house for 30 cents, it being listed as a " strap key." I made a small coil which would give a 1/2-in. to 3/4-in. spark, according to battery power. For Leyden jars I followed instructions found in a back number of Amateur Work, using two glass tumblers instead of one larger jar. When the coil key and wiring were connected and one side of the spark gap connected to the aerial and the other to the earth, I was able to radiate enough energy into the air and earth to send distinct messages from one end of the village to the other. Fig. 1 shows a diagram of transmitter connections.

Fig. 2 illustrates the receiving end. The receiver consists of a tripod of three needles with a coil of finest copper wire connected to the top and connected to the aerial binding post. This tripod rests on a small slab or block of carbon, selected for its smooth surface, and this carbon block is connected to the earth. A weak cell of dry battery and the telephone receiver are connected to bridge the tripod and carbon. A choke coil, consisting of a small bundle of iron wires, covered with a hundred turns of fine covered magnet wire was connected between the battery and the telephone receiver. This device greatly improves the signals.

The messages came in long and short distinct buzzes according to the length of time the sending key is de-pressel. Any code may be used, preferably the American Morse. This outfit seldom gets out of order, and will operate regardless of temperature and other weather conditions, if constructed in a neat manner. It requires no relay, sounders, decoherers and other expensive devices. Improvements, as they suggest themselves, may readily be applied at small cost.