Wireless Telegraphy and Telephony

2Ö WIRELESS TELEGRAPHY The wires leading from the aerial to the operating room are called the “rat-tail,” or “lead-in.” They must be very carefully insulated by leading through a bushing placed in the wall or window of the operating room. One of the most important factors in a wireless station is the proper earthing arrangement. The usual method is to use large copper plates buried in moist earth, or thrown in the sea. On shipboard it is merely necessary to con- nect the earth wire to the metallic plates of which the hull of the vessel is built. Amateurs employ the water or gas pipes in the house, the former being preferred. Connec- tions are established by means of a ground clamp. In the country, where water-pipes are not available, the best way is to bury a sheet of copper three or four feet deep in moist earth. A very efficient earth can be formed by spreading a large area of chicken wire netting over the ground. This method is the best where the earth is very dry or sandy, and no other way is readily convenient. Fig. 27.—A side view of the aerial shown in Fig. 22.