Amateur Radio & Radio Communication

Amateur Radio

Many people were attracted by radio when it first came out and became amateur radio operators. These very people discovered that shortwave radios could communicate to long distances or practically all across the world. Therefore, these amateur operators keep communication up with their fellow operators all over the world in case of emergencies and natural disasters.

Ham radio or amateur operators are assigned call signs by the government and have to give a written exam to get the license.

Citizen Band Radio

Around the vicinity of 27MHz lies the citizen band with about 40 channels. These channels are for the purpose to two way business and personal communication with one channel dedicated to emergencies. Similarly to amateur radio, citizen band also requires a license, but the citizen band operators have lower privileges than the amateur operators.

Federal Communication Commission

The FCC (federal communication commission) is the regulatory authority that oversees all forms of radio communication in the United States of America. They have a few regulations, and violations of these can cause severe penalties. This updated regulation can be gotten after writing to them.   

Radio Communication

Radio communication has come a long way from what they initially were. In 1886, Mr. Heinrich Hertz performed his experiment, which is later known as the hertz experiment, in which he confirmed that electromagnetic waves do travel at the speed of light. This was done by sending waves from a spark discharge to a loop of wire a few yards away. The loop of wire had small holes in it, causing then to spark. Note that the spark was only visible in a dark room. In 1895 Guglielmo Marconi created the world’s first working telegraph, and in the next four years, he was able to send a message (“…”) across the Atlantic.

Modulation

Modulation is when an information-carrying wave (voice, message in other forms) is mixed with a higher frequency wave called the carrier wave. Modulation is usually done for two reasons; the first one is that it helps us send a signal over a bandpass range, meaning every signal gets its own frequency range, allowing us to send multiple signals simultaneously over 1 channel. The second is that modulation will cause us to use a smaller antenna. The types of waves seen in modulation are as follows

Damped Wave Or Spark Wave

This type of wave is only ok for code because it emits multiple wavelengths, so it is not particularly legal for communication purposes.

This is a pure, unmodulated radio frequency wave. As it has no distortions and the same signal keeps on repeating itself, it does not carry any signals.

Amplitude Modulation

As seen clearly, there is a distortion in the amplitude. This means that the carrier wave is modulated so that the frequency is the same, but the amplitude varies. This type of modulation is usually done for sending voice messages.

Frequency Modulation

Frequency modulation is when the amplitude is constant, but the frequency varies, clearly visible above. This type of modulation is also used for voice messages and ensures noise-free reception.