Diagram showing the principle by which the Aerials are connected to the Apparatus.
CHAPTER XXI
WIRELESS TELEGRAPHY IN WAR
The history of this wonderful invention has been described in the preceding chapter. Now we will see how it is applied in warfare.
Let us take first its uses in connection with the Navy. The aerial wires or antenna are stretched to the top of the highest mast of the vessel. Where there are two masts they often span between the two. Ships which have masts for no other reason are supplied with them for this special purpose. In the case of submarines, the whole thing, mast and wires included, is temporary and can be taken down or put up quickly and easily at will.
The stations ashore are equipped much after the same manner as are the ships, except that sometimes they are a little more elaborate, as they may well be since they do not suffer from the same limitations. For example, the well-known antenna over the Admiralty buildings in London consists of three masts placed at the three corners of a triangle with wires stretched between all three.
However these wires may be arranged and supported they are very carefully insulated from their supports, for when sending they have to be charged with current at a high voltage and need good insula
tion to prevent its escape, while, in receiving, the currents induced in them are so very faint that good insulation is required in order that there may not be the slightest avoidable loss.