Before satellite radio came around, listening to radio while on the move was troublesome. This is because radio stations’ transmitters are powered to certain levels and are not capable of travelling vast distances. A lot of radio signals are only able to travel around 35 miles. As such, if you were in the car, for example, on a long trip then you would have to keep switching your radio station to get the signal with the highest signal strength. It is a bit annoying and temperamental – the radio could completely cut out during your favourite song, and no one wants that. These problems went away with the introduction of satellite radio.
Satellite radio, also known as digital radio, offer high quality audio with no static. The signals sent by satellite radio are capable of travelling vast distances. The signals are being broadcasted from space, so they are able to transmit to you wherever you are.
Satellite radio was born in 1992. The United States Federal Communications Commission allocated a spectrum in the 2.3 GHz signal band for nationwide broadcasting of Digital Audio Radio Services. At the time, only four companies applied for a license to transmit. These companies let listeners pick up a huge variety of radio stations, offering a whole load of genres.
So how does it all work? There is a station on Earth that transmits a signal to all the satellites that are orbiting the planet. The satellites then bounce the signals back down to the satellite radio receivers on Earth. These signals contain the audio track, the title of the song and the artist. The receivers are capable of unscrambling the data sent from the satellites.
The reason that satellite radio transmits such high quality sound is that the music is being digitally compressed. This makes it possible to put as much quality into the bandwidth as possible. Satellite radio signals are built to process this, but this comes with a cost. This is why satellite radio in the United States is charged for. The two main companies are Sirius and XM (who merged in 2008). They offer mostly advertisement free radio to their millions of subscribers.
Sirius’ satellites orbit the Earth in an oblong shape. This allows their satellites to reach higher in the sky and very rarely lose their signal. XM’s satellites are geostationary and orbit Earth relative to the customary movements of the planet. When their signals are received down below they are then retransmitted using XM’s antennas. This allows the audio to broadcast uninterrupted in built up areas where satellite signals have trouble broadcasting to.
Satellite radio works much in the same way as digital TV. It requires the same three parts. These are the digital broadcast satellite, a ground antenna and a receiver. Like digital TV, satellite TV offers a subscription fee so that users can listen to the radio stations that they want to. Each receiver is identified through an Electronic Serial Number, which allows unique signals to be received by the user.
Hopefully now you understand how satellite radio works. It is a relatively simple, yet clever, technology that makes listening to the radio a joy.