If you want to have your own scanner, expect it to cost anywhere from $50 to $500. If you're not ready to make that sort of investment, you can rent one the next time you go to the racetrack.
Depending on the model -- handheld, mobile or base -- a scanner looks like either a walkie-talkie or a dashboard radio. A scanner also works a lot like a walkie-talkie or a dashboard radio. Scanners pick up radio frequencies, after all, and the best ones don't gather dust on non-race days -- they're designed for multiple uses, such as listening to public safety and news broadcasts and tuning in to police and military frequencies, ham radio and even CB communications.
Every team in a given race has a different frequency. Frequencies change based on the race, the series and the track. In addition, the track workers have their own frequencies.
A scanner assigns each frequency a different channel. At a race, there might be 200 frequencies of interest, so you should make sure your scanner has enough channels to cover them all.
Fancier scanners -- and of course, rented scanners -- will come to you already configured with known racing frequencies, so you don't have to program them. For some series, such as the Sprint Cup, subscription services such as TrackPass provide the programming.
Beyond that, using your scanner is pretty much a matter of channel surfing. How you surf depends on your scanner and your preferences. You can set your scanner to jump automatically between drivers' frequencies, so you get a balanced view of the race. You can also program the scanner to ignore certain drivers or frequencies.
If you do choose to jump between channels automatically, make sure you know how to override that feature in case something exciting happens. If there's a crash, you don't want to be stuck listening to an unrelated frequency.
Now, if your scanner doesn't arrive preconfigured with frequencies, you have some research to do.