Portable Satellite Radio Buying Guide: Powered by ConsumerGuide and HowStuffWorks

The Basics: Portable Satellite Radio

Howard Stern, Oprah Winfrey, the NFL, Fox News -- it seems that the programming choices that are available on satellite radio are exploding. There is a good reason for that: If XM and Sirius don't get subscribers, they won't make any money. Thus, they both pay and pay for programming. This is all good news for the consumer.

Terrestrial radio is a consumer electronics technology that hasn't changed very much since families gathered around the home radio to listen to the "serials." Granted, FM radio greatly increased the quality of the signal, adding stereo and overall fidelity to the sound. However, it is still limited by distance. Stations drift, you drive out of the range of a favorite station, static abounds, you travel to a region that doesn't have any music you want to hear...the complaints abound. Yet despite all this, radio remains a popular way of tuning in.

Now, imagine yourself on a road trip, and you are able to listen to digital music on any one of well over 100 stations across the entire continent. No static, one station of your choice, 24/7 wherever you are. Currently, XM and Sirius are the two companies pulling this off. The two companies use slightly different technologies, as well as independent satellites offering completely independent programming. XM has two satellites in geosynchronous orbit over the equator, while Sirius uses three satellites that loop in figure-eight orbits over North and South America (the system is only available in the continental United States.) XM beams from its headquarters in Washington, D.C., and Sirius is based in New York.

Both satellite radio providers have a huge variety of music channels, sports, talk and news, including feeds from CNN and Fox. Although digital, the sound is not CD quality. Both service providers use data compression, which sacrifices some audio quality. In urban areas where there might be interference from tall buildings, both systems use repeaters. Neither system will work in tunnels or parking garages, but the receivers usually have a small memory buffer to fill in for an occasional dropout. Both XM and Siruis charge a monthly fee. After you're enrolled, your receiver is activated and ready to receive signals.

How to Shop

The two companies are currently completely independent of each other; if you have an XM receiver, you cannot listen to Sirius stations. Also, manufacturers are aligned with one or the other. If you buy a Panasonic satellite receiver, it will only carry Sirius. Kenwood, Clarion, and Jensen also supply Sirius, while Pioneer, Alpine, and Sony supply XM. Both companies have websites where you can listen to the program lineup each offer--this is the deciding factor for many people. Initially, the sound quality of XM had a noticable edge over Sirius, but improvements have closed the gap.

If you're happy with your current head unit, you can get a tuner that connects via FM modulation or with an auxiliary input. Or, you can get a satellite-ready head unit that will control the satellite receiver as well. These typically are brand-specific, so if you buy a Kenwood head unit, you will have to buy a Kenwood tuner. Some head units have an integrated satellite tuner, eliminating the need for the extra component. In addition, some newer CD and cassette systems incorporate a satellite tuner, and these are covered in this website's car audio CD player and in-dash cassette player sections.

Antishock Memory

A feature of CD and MiniDisc players that stores audio data in a memory buffer that is output if the main signal mistracks.

Antitheft Protection

A variety of ways a system attempts to prevent theft, including a detachable faceplate, a masking face plate, or systems that will not operate if disconnected from the battery without a custom code.

Band-Pass Filters

High- or low-pass filters remove the frequencies above or below the range selected by the filter, changing the frequency response through this form of equalization.

CD Text

Data encoded on a small number of CDs that will display disc title, artist and song titles on CD Text compatible players.

Changers

A CD, MiniDisc, DVD or MP3 unit that handles more than one disc--a multiple player.

Digital/Analog Tuner

An analog tuner uses conventional circuitry with a tuning knob or thumbwheel and pointer to show you the frequency to which you are tuned. A digital tuner, more accurately a synthesized tuner, permits using a digital frequency read-out and presetting radio stations for touch tuning.

Direct Access

Using a numeric keypad, you simply press the corresponding key to hear a specific track.

Distortion

This is a measurement of the deviation from the original signal to the reproduced signal. Distortion is a harsh sounding artifact that alters, in a negative way, the signal.

Dynamic Range

The difference between the loudest peak and softest passage. It can also refer to the spectrum between the edge of distortion at the high end of a product's performance and the product's noise floor.

Equalizer

A circuit or program that changes the frequency response of a signal, boosting or cutting selected ranges from the overall response.

FM Modulation

For someone unwilling to remove their factory installed equipment, an FM modulator takes the audio output of an FM-modulated add-on and generates a radio frequency (RF) signal that is received by your car's FM radio tuner.

Frequency Response

Also listed as Frequency range, is the spectrum of frequencies produced by a product, within a certain tolerance. For example, a frequency response of 30Hz to 18kHz (+/- 3dB) means a product produces all frequencies from 30Hz to 18,000Hz without dropping or peaking three decibels. The signal below and above that range does drop off more than 3dB, so the range is really the usable spectrum of sound.

Head Unit

The usable part of a component that is mounted in the dashboard is commonly referred to as a head unit. It controls the components, either internally or remotely installed, such as a changer mounted in the glove compartment or trunk.

OEM (original equipment manufacturer)

This refers to the factory-installed system that comes with a car. Many car manufacturers are using name brand products, either standard or part of an upgrade package.

Peak level search

A feature that scans through an entire disc for the loudest section--the loudest peak, to let you properly set record or even listening levels

Player

Whereas a changer plays many discs, a player can hold and play only one at a time.

Preamp Output

Generally, an RCA jack that sends the signal to an external amplifier--before the signal is amplified internally.

Programmable

Customizing the playback order of tracks on a CD, MiniDisc, MP3 player or even a cassette by storing your own play list, or using a random function that scrambles the order, or selecting one track to repeat.

RDS

Radio Data System transmits station information along with the regular audio to RDS-ready radio receivers.

Signal-to-noise ratio

The ratio between the audio signal and noise floor. A low number indicates that the noise and music are closer together--the higher the number, the less noise is apparent.

Portable Satellite Radio Buying Guide

The Basics: Portable Satellite Radio

How to Shop

Glossary

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