Question: What is a satellite radio antenna?
Thinking about getting satellite radio in my car, but I’m not sure what the deal is with satellite radio antennas. Don’t you need a dish to receive signals from a satellite? I’ve never seen any cars driving around with dishes on them. Will my regular car antenna work, or do I need some kind of special antenna (dish) to receive satellite radio?
The simple answer is that you do need a special antenna to receive satellite radio. Your car radio won’t cut it because, unlike FM radio and HD radio, satellite radio and FM radio aren't broadcast on the same frequency bands. This is why you don't need a special HD radio antenna, but you do need a special satellite radio antenna.
However, your observation that you’ve never seen a car driving around with a satellite dish is astute. Satellite radio, unlike satellite television, doesn’t make use of dishes. The main reason is bandwidth, but suffice it to say that satellite radio uses small, non-directional antennas (similar to many satellite phones you may have seen).
Why You Need a Satellite Radio Antenna
Both terrestrial radio and satellite radio use omnidirectional antennas, which can be contrasted with the directional antennas used by satellite television services. However, your existing car antenna that’s designed to receive AM and FM signals isn’t capable of receiving satellite radio transmissions. The issue is that the FM broadcast band occupies part of the very high frequency (VHF) radio spectrum, the AM band utilizes part of the medium frequency (MF) band, and satellite radio occupies the S band.
Although there are slight variations between different countries and regions, the North American bands are:
AM radio: 535 kHz to 1705 kHz
FM radio: 87.9 to 107.9 MHz
Satellite radio: 2.31 to 2.36 GHz
Why Satellite Radio Doesn’t Use Dishes
First of all, it’s important to understand that a satellite dish is actually just a specialized type of antenna. They’re referred to as directional antennas because they are designed to receive signals in a cone that projects outward from the edges of the dish, which is why you have to aim a satellite dish at a particular portion of the sky for it to work. The main benefit of this type of antenna is that it’s capable of receiving a greater amount of information from a weaker signal than an omnidirectional antenna would be able to. In that same vein, directional antennas can actually be used to receive weak television and radio signals in remote areas, distant Wi-Fi signals, and other types of weak or distant signals.
As to why satellite radio uses omnidirectional antennas and satellite television uses dishes, it really comes down to the amount of information that has to be transmitted for the different services. Audio transmissions take up less bandwidth than television transmissions that include both an audio and video component. So while satellite television providers could have used omnidirectional antennas, they wouldn’t have been able to offer very many channels.
Installing a Satellite Radio Antenna
Since satellite radio antennas are omnidirectional, you don’t have to worry about pointing them in any particular direction. However, it is important to position a satellite radio antenna so that it has an unimpeded view of the sky, and it just as vital to choose a location where it won’t receive any sort of interference.
If you drive a vehicle with a hard top, then the antenna should be installed:
- near the front or rear of the roof
- three inches or more from the edge of the roof
- three inches or more away from other antennas
- somewhere that a roof rack (or other similar accessory) won’t block the sky
If you drive a convertible, you obviously can’t mount a satellite antenna to the roof. In that case, you’ll want to install it:
- on the trunk near the base of the windshield
- on the hood near the back edge
- three inches or more from the edge of the hood or trunk
In any case, never install a satellite radio antenna:
- inside the vehicle
- less than three inches from antennas, roof racks, and other accessories