Radio Bargains
Welcome to radio bargains. On this site you’ll find a great selection of different radios. There are both new and used items, many at well below retail price.
Just take a look around to find what you are looking for.
Radio can be used for many things. These include maritime uses. This was one of the earliest adoptions of radio and it was used to send telegraphic messages between the land and ships, or even between ships.
Audio radio: AM radio uses what is known as amplitude modulation. This basically means that the amplitude of a transmitted signal is always proportional to the amplitude of the sound that is captured by a microphone. The transmitted frequency however, remains unchanged.
In FM radio both music and voice can be sent with a higher level of fidelity and an FM signal isn’t susceptible to the same static and interference as an AM signal. The higher bandwidth also means that it is transmitted in the VHF spectrum.
Cell or mobile phones originally also used an FM signal. Now however, generally different digital modulation schemes are used.
Television also uses AM to send pictures, whilst it sends sound using both AM and FM.
Radio also plays a major role in navigation, or modern navigation at least. The way it works is that satellite systems use precises clocks. When the satellite transmits it’s position it does so at a specific time, so that the receiver can compare the data with four other satellites and then figure out where it is based on a line that is tangent to the round shape of the satellite. The oldest form of radio navigation is called radio direction finding.
RADAR stands for radio detection and ranging. Simply put the system bounces radio waves off objects and then determines the distance from that. Whatever direction the beam goes in actually determines the direction in which the reflection goes. This can also be used to look at the type of the surface based on frequency and polarization. Radar is of course, used frequently on the seas and in the air. Although currently, most new radio systems are digital.
Heat can also be generated from radio. An example of this would be microwave ovens, that use intense radio waves for food. It can also be used in things like surgery. Here diathermy equipment seals up blood vessels. There are also induction hobs in ordinary cooking and induction furnaces used commercially for casting, and melting metal.