Thanks to your cable television package and your Internet connection, it's easy to keep up with events on the other side of the world. Yet, it can be surprisingly difficult at times to find out why emergency vehicles were speeding past your house last night. Radio-frequency scanners fill this gap, making it possible for you to listen to emergency vehicles, municipal work crews, passing aircraft and most other sources of radio signals. Scanners actively monitor your chosen frequencies, and stop to let you listen whenever there's an active signal. Choosing which one to buy requires some basic knowledge.
Scanners are available in mobile versions and larger at-home or "base" models. Some can also be mounted in or under a car's dash, like a CB or a car stereo. Regardless of their format, all scanners work in much the same way. They're designed to receive a range of commonly-used radio frequencies, letting you listen in and hear your local news while it's fresh. You can add interesting frequencies by scanning, and saving the ones you like into memory. Alternatively, you can download lists or buy scanner-frequency books. Your local Radio Shack stores can often provide frequencies used in your community.
Range of Features
Although all scanners function similarly, some are more capable than others. You can expect to pay more for a scanner with a larger number of memory slots for stored frequencies. The frequencies are usually organized into banks of 10, 20 or more frequencies, with better scanners having more banks to use. These are convenient for groups of related entities, such as ambulance services. As a rule, higher-priced scanners receive a wider range of frequencies with fewer gaps in their coverage. Capable scanners also let you enter specific frequencies down to the last digit. Entry-level models might only program in 5 Khz steps, missing frequencies in between.
Cautions and Limitations
It's important to understand that you can't necessarily listen to everything you want. You won't be able to pick up cellular phone conversations, and in any case it would be illegal. It's also illegal in most jurisdictions to modify your scanner so it can decrypt encrypted signals. In some areas it's illegal to listen to your scanner while you're in your vehicle, because criminals could use them to evade police pursuit. You can also be prosecuted in many areas if you use your scanner for personal gain, such as stealing customers from a business rival.
Choosing a Scanner
Once you've decided to buy a scanner, settling on the right one can be a challenge. Take the process in easy stages, once decision at a time. If you're active and want to have your scanner with you at all times, a walkie-talkie sized mobile might be your best bet. They'll usually cost slightly more than a base unit with comparable features. Base units are usually more sensitive and have larger memories, making them better for serious enthusiasts. Getting lots of memory is important, since one radio source might use dozens of frequencies. When in doubt, ask store staff or local radio clubs for their guidance.
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