MOUNT DESERT – Do you like a great sound when you drive? Take a look at XM Satellite Radio.

XM offers 100 channels of music, news from CNN and the BBC, and comedy. More than 30 channels are commercial-free with music in every category imaginable, including opera and jazz. I understand that commercials can be found on some of the channels, but not the ones I listened to. There are channels assigned to each decade extending back to the 1940s, while channels such as XM Cafe (channel 45) and Fine Tuning (channel 11) offer a wide range of music.

Two of the 2002 Cadillac models come equipped with XM Satellite Radio and General Motors alone will have more than 20 different car models available with the system in 2003. You can also buy the system for your own car locally from Sears, Circuit City and Best Buy in Bangor.

My test of a Sony-built XM Satellite Radio system on Mount Desert Island greatly exceeded my expectations. The Sony unit (DRN-XM01) I installed in my car is a portable unit that is designed for both car and home use. It includes a cassette-shaped connector that plugs directly into any car cassette slot along with a power plug for a cigarette lighter. A stubby 4-inch antenna that resembles a sawed-off shark’s fin mounts on the car roof. Installation is quick and easy. I took about 10 minutes to complete the task.

Is it expensive? Well, it is not inexpensive. This particular model of a satellite radio costs almost $300, plus you have to purchase the car installation kit, including connector, power plug and antenna. If you want to use it indoors, then you have to buy another power plug and antenna. Then you will be billed a monthly subscription fee of $9.99. Still, XM Satellite Radio reports that more than 30,000 people have signed up since the service launched last fall.

The realm of car audio has plenty of room for satellite radio services. In this era of MP3’s and CD burners, this satellite radio offers comparable audio quality. Whereas the CD revolves around a preprogrammed listening experience, XM Satellite Radio is the ultimate in radio linked to a vast music library. On Feb. 14, Sirius Satellite Radio rolled out a competing service that costs slightly more per month in Denver, Houston, Phoenix and Jackson, Miss. It is not known when Sirius will be available in Maine.

One note of caution is in order. Because we are located in the far northeast corner of the country, Maine is not the most satellite-friendly environment. There are plenty of places on Mount Desert Island, where I live, and elsewhere statewide that are dead zones. A satellite signal is blocked anytime the satellite antenna in question loses its direct line of sight access to the satellite. If you see a large mountain or any steep hill or even a clump of high trees off to the southwest of your car, do not be surprised if your satellite radio suddenly cuts out.

XM Satellite Radio has addressed this problem by engaging in what is known in the satellite business as “forward error correction and interleaving,” which makes sure that the radio taps the stronger of two signals from company’s twin satellites, which are named Rock and Roll. The result is that the signal is remarkable in its range and consistency.

Frankly, I am astounded that signal outages are not more frequent. In more than three weeks of testing in the very hilly terrain of MDI, I found that the signal was there more than 99 percent of the time, and when signal loss did occur the longest gap I encountered was about 8 seconds with about 4 to 5 seconds as the average span. Thickly wooded camp roads in particular can and will present a problem. Otherwise, the XM Satellite Radio signal passed an intensive reception test here on MDI with flying colors. Surprisingly, when the signal cuts out on a specific stretch of road in one lane, no loss or degradation is experienced in the opposite lane.

The Sony unit I tested included a remote control, and while I have been told that remote controls are less distracting than fumbling with the control buttons on a car audio system, I skipped the remote altogether. Instead, I elected to preset the five channel buttons to my top picks in five different categories. Once I did this, I used the thumb scroller atop the radio to cover a lot of different channels. A two-line display lists song titles and artist information in addition to the channel number.

Satellite radio is a work in progress, and the sound is terrific. XM Satellite Radio is heading down the right road. Besides this portable Sony unit, XM Satellite Radio systems are available from other vendors, including Pioneer and Alpine. I saw two Pioneer units at Sears in Bangor.

In summary, I did not attempt to listen to every channel available on my system. I probably never will. But I can guarantee that you will like what you hear. You will like it a lot.

Peter J. Brown is a free-lance writer from Mount Desert.