The Morse Telegraph was the first electric form of communication. It began with a device that perforated paper making dots and dashes that were later transcribed by the operator. Later the operators used the clicking of magnetic magnet solenoids to listen to and hand record the messages. These messages were received and transmitted at speeds of 40 to 50 words a minute and relayed from one station to another until they reached their destination.

Wireless communications grew out of a need for military communications where wires were not practical and a need to communicate with ships at sea

In the early days of wireless communications, which later became known as radio, the only method of creating a radio wave was the spark gap transmitter. These were basically an LC circuit and a battery. The vacuum tube had not yet been invented and the only way to create a radio oscillation signal was to use a high voltage spark that was oscillated by the rising and collapsing of a simple Inductive coil coupled with a capacitor.  The spark gap discharged the capacitor when the voltage reached sufficient level to jump the gap. The resonance of the induction coil used in combination with the capacitor determined the frequency but the spark created a wide sideband of interference taking up great chunks of bandwidth. 

These spark gap transmitters were generally low frequency between 400 khz and 800 khz. Because of the very wide bandwidth, only a few stations could transmit on the band at a time without interfering with one another.

Radio experimenters built their own spark gap transmitters often using the ignition coil out of the Model A Ford and home made capacitor plates. These amateur radio enthusiasts sometimes interfered with government and comercial transmitters because of the wide bandwidth of the spark gap radio signals.

There is speculation that communications between the RMS Titanic and a rescue ship, may have been interfered with by one or more radio experimenters.

Because of this the US government banned amateur radio experimentation except at wavelengths below 200 meters (above 1.5 mhz), at the time short wave was considered useless, and they created the Radio Act of 1912. This act established licensing for Amateur Radio experimenters and set rules for proper operation. The International Convention for the Safety of Life at Sea (SOLAS) created the first internation communications treaty.

Amateur radio operations were suspended durring WWI and again during WWII however radio amateurs were encouraged to be listeners of the airwaves and to report any radio signals they intercepted to the military.

After WWII Amateur radio was again authorized and many amateur radio operators found surplus military equipment that was easily converted for use on the alotted Amateur rado frequencies. The ARC-5 series of radio transmitters is a good example of such equipment.



http://www.youtube.com/watch?v=6ybYxkt3UxU

http://www.youtube.com/watch?v=QVgQcj7jihk

http://www.youtube.com/watch?v=cREAy3euVLg&NR=1