We take it for granted that when we switch on our radios, sound will be transmitted – but have you ever stopped to wonder exactly how that happens?
It all starts at the radio station, where sound is captured via microphones and converted into electrical energy. This is captured and forced through a transmitter, which is essentially a very tall antenna. Electrons in the current create electromagnetic radiation, which are known as radio waves, and these are projected from the top of the transmitter. Radio waves travel at the speed of light, so they reach the receiving antenna instantly.
Radio waves can travel in straight lines horizontally, via ground waves along the curvature of the earth or into the sky, where they bounce off the earth’s ionosphere. Medium wave radio, also known as AM radio, uses ground waves over short distances, and the ionosphere over longer distances.
When you switch on your radio, the radio waves are picked up by the antenna on your set, and as they flow down the metal rod the electrons generate an electrical current which is converted by the radio’s components into sound.
Types of Antennas
Both the transmitter and receiver are types of antennas, although they both perform different jobs. Anything which transmits or receives a signal is an antenna, and they come in a huge variety of shapes and sizes. Even the satellite dishes seen on so many houses are a type of antenna – these are known as parabolic reflectors, and their distinctive bowl shape helps to collect radio waves more effectively. Television masts are also types of antennas. They are often extremely tall, as this helps them to distribute their signals across a wider area.
Digital televisions don’t necessarily require a satellite dish. In fact, Digital UK recommend that for Freeview services an old-fashioned aerial is the preferred piece of equipment, although it does need to be of a modern type, properly aligned and with good-quality cabling. For best results you should use the services of a qualified installer, such as Gloucester TV aerial repair services http://steveunettaerials.co.uk/services/tv-aerials-repair-and-installation-gloucester/.
Digital televisions can also pick up digital radio stations, and many people nowadays are choosing this option for home listening, using portable radio sets for days out or when working away from the home.