Land stations were build near places at the coastline where shipping tracks pass by, to link
the telegraph landlines with the ships in surrounding areas by means of wireless telegraphy.
At the beginng of the maritime
mobile service spark transmitters were in use with power levels up to a kilo Watt range.
At first there was a simplex traffic,
transmit and than switch to receive and vice versa, because frequency selection and
stability was very poor.
The receiver was of a mechanical typ, the so called fritter.
Filage of iron powder in a glass tube reacting to the magnetic field of the waves make
the filage to fritt and so change conductivity of this device (Edouard Branley).
The anglo italian wireless pioneer Marconi uses a direct induction to the antenna whereas
the german physisist Braun created the coupled, closed circuit with coil transformer to the
antenna. This kind of wiring caused a strong and prolonged damped wave.
Marconi 1898 |
Braun 1900 |
In the early days of wireless only damped waves could be produced.
