The Receiving Set
Perhaps the most fundamentally important part of a wireless telegraph station is the aerial. Its construction varies with each station, but a few general suggestions may be of use.
The builder should aim to get as high and as long an aerial as possible, height being the more important factor. In a stationary set the aerial may be fastened to a tree or pole or high building while in a field set a tree or an easily portable pole must be used.
The aerial itself should be made of copper wire and should be hung between spreaders as long as convenient and insulated from them by two cleat insulators in series at each end.
The experimenter should see that his leading-in wire is placed conveniently and comes in contact with the walls, etc., {212} as little as possible. All points of contact must be well insulated with glass, porcelain, or hard rubber.
The tuning coil is very simple in construction. A cardboard tube, about three inches in diameter, is mounted between two square heads. This tube is wound with No. 24 insulated copper wire and very well shellaced to avoid loosening of the wire.
Two pieces of one quarter inch square brass rod, to be fastened between the heads, are secured, and a slider, as shown in drawing, is made. The rods are fastened on the heads and the insulation in the path of the slides is then well scraped off. Binding posts are then fastened to rods and coil ends.
Details of instruments for field use.
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