Sirius AM Radio

AM means, Amplitude Modulation, and that is the technology used in AM broadcasting. The very first AM broadcasting was in 1906 by a Canadian experimenter Reginald Fesseden, and this continued in a small way, until World War I. Sirius is a satellite radio company which uses satellite technology for its broadcasting and their first broadcast was in 2002. Sirius has three powerful satellites in geo-synchronous orbit, and the radio service covers the full of mainland United States and Canada.

Radio programs are developed in the Sirius studios, and then the studios, uplink them to the satellites. The satellites which are at about 22,000 miles above the earth, beam down these signals over the designated area. In urban areas where there is a concentration of high-rise structures, Sirius has installed terrestrial signal repeaters to provide an uninterrupted stream of signal to its customers.

AM radio stations use transmitter power input to their antennas to transmit the radio signals. The power of the transmitter usually ranges from 250 to 50,000 watts. The power will determine the area of coverage, and usually it will be around a radius of few hundred miles. AM radio signals travel by ground-wave during the day, and by night it travels by skywave. This is why, at night the coverage of an AM broadcasting station increases, as compared to, during the day.

Satellite radios are alloted the 2.5 GHz S-band frequencies. Sirius separates its signals into three carriers, two for the satellites and one for the terrestrial repeater network. The Sirius radios decode all the three 4 GHz carrier signals at once to achieve an unbroken stream. There is a 4 second delay between two carrier signals from the satellites, which enables the receiver to have a buffer of the audio stream and also have a forward error correction in case the signal is temporarily lost, due to some obstruction, in the line of sight of the radio antenna and the sky.

Many frequency bands are used to broadcast AM radio, and their allocation is usually governed by ITU Radio Regulations and also other regulations at the national level. The Long Wave is between 148.5 kHz to 283.5 kHz, and is used in radio broadcasting in Europe, Africa and certain parts of Asia. A spacing of 9 kHz is used between channels. The Medium Wave is between 520 kHz to 1,610 kHz, and this is the most heavily used frequencies for commercial broadcasting, and many people term this to be AM radio. A modified version of AM is the Short Wave which is between 1.711 MHz and 30.0 MHz, and divided into 15 broadcast bands. These frequencies can be heard over great distances, but their sound quality will be very poor.

The programming content of Sirius radio is far superior to any AM broadcasting service. Sirius has over 130 channels of high quality entertainment comprising of commercial-free music, sports, entertainment and news. Sirius charges a monthly subscription fee to its customers, and you need a special satellite radio to receive their signals. AM radio is free, but their programming will be spaced by many commercials and you will not get the same variety and quality of content that you receive in Sirius.