How does Satellite Radio Work?

Posted By BrokenClaw on October 7, 2007

Satellite radio is a digital broadcast of traditional styles of radio programming available only by subscription. As the name implies, the radio signal is transmitted from communication satellites, instead of terrestrial radio towers.

In the US, the two providers are Sirius Satellite Radio and XM Satellite Radio. In order to receive satellite radio, you have to purchase the branded receiver, which can be smaller than an eyeglass case, and you have to pay the setup fees and a monthly subscription. Satellite radio can be set up in your home with connections to your stereo system, or carried in portable devices, but it’s mostly designed for automobiles. The obvious advantage over terrestrial radio is that the satellite signal can blanket a wide land area. With only a few satellites, the service covers most of North America.

Both Sirius and XM have made agreements with some vehicle manufacturers to make their receivers an optional accessory on new purchases. More commonly, you purchase a receiver and install it yourself or have it professionally installed.

Since it is receiving a signal from space, satellite radio requires a different type of antenna. The terminal end of the antenna is a small disc about the size of a Peppermint PattieĀ®. Like a GPS device, it must be positioned on the outside of the vehicle with a direct line of sight from the satellite to your antenna. In other words, it will not work when the vehicle is under a roof or inside a tunnel or a parking garage. The signal can also be blocked by tall buildings or other obstructions. Be aware that airports and military installations may also block satellite transmissions.

The satellite receiver has no speakers of its own. It has to play through your regular radio speakers in the car. If your car stereo is equipped with an input jack, you can connect the satellite receiver directly and play it as you would a portable music player. Otherwise, you have to use the receiver’s FM signal to play through your stereo.

For most do-it-yourself installations, that means that the satellite receiver becomes its own FM station, and you just set your FM dial to the corresponding frequency. The receiver is powered by a connection with your car’s accessory plug. The disadvantage is that you may experience some interference from actual FM stations, depending on the stations around you. Professional installation offers a cleaner setup with a hard-wired power supply and a hard-wired FM connection.


Both Sirius and XM offer a wide range of programming with over a hundred stations. Each station covers a unique style of music, talk, sports, and entertainment, as well as news, traffic, and weather. For sports fans, it is a choice between Sirius’s NFL coverage and XM’s Major League Baseball coverage. As a subscription service, satellite radio is also open to adult type content, which is clearly identified. Some of the stations are simulcasts of terrestrial radio, so they include the normal commercial breaks, but the music stations are generally commercial-free.

Satellite radio is popular among professional drivers, such as truckers on long haul, because the satellite signal remains the same no matter where they go. It is also appealing to anyone who desires commercial-free music or a variety of audio entertainment that is not available on their local radio stations. However, as digital music, podcasts, and Internet radio became more pervasive and more accessible on portable players, satellite radio seems to have a diminishing appeal.


In July, 2008, a year after they announced their intent, the merger of Sirius and XM was finalized. Since the services are carried on separate channels, the receivers from one service do not work on the other, so the benefit to subscribers is minimal. Most of the duplicated content, particularly the music and news channels, were consolidated. A few other channels were added to the other service. Additionally, subscribers are offered an upgrade package, at an increased cost, to receive the premium content from the other service.


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