| Hand held radio scanners are often used for listening | | | | are usually larger in size, but because of that they |
| to emergency services, but there are other types of | | | | might have additional features that the portable models |
| communications that you can listen to also. They are | | | | can't because of their smaller size. |
| usually used as a hobby, but they are also handy for | | | | Scanners today are capable of being programmed |
| investigators, journalists, and volunteers. | | | | with the ability of storing thousands of channels, and |
| Even though a lot of people call these radios police | | | | can monitor them in the hundreds per second. They |
| scanners, they can receive signals transmitted from a | | | | are meant to monitor and scan local VHF and UHF |
| large range of frequencies, and so you are able to | | | | bands in the RF frequencies. They also handle various |
| listen in on air traffic control, fire and ambulance | | | | methods of modulation such as AM, FM, and WFM. |
| services, race teams, and much more, as well as the | | | | Basic hand held radio scanners usually have 100 |
| police transmissions. | | | | channels, which is probably sufficient for someone just |
| The most popular of hand held scanners are the | | | | starting out for a hobby. More sophisticated models |
| Uniden radio scanners, especially the Uniden Bearcat | | | | have up to 25,000 channels. An average scanner will |
| scanner. The bearcat scanner line starts with a basic | | | | pick up transmissions up to 40 miles away, depending |
| model with 100 channels, and goes all the way up to a | | | | on the antenna being used. The scanner has a vast |
| model with 25,000 channels, with many choices in | | | | range of frequencies to scan usually between 29 MHz |
| between. | | | | and 512 MHz. |
| Modern scanners are controlled by microprocessors | | | | Basically a scanner is a radio communications receiver |
| and micro electronics and are designed to be light | | | | that can automatically scan, or tune into, at least two |
| weight and portable. Back in the 1970's, when they first | | | | frequencies. They have a squelch setting that can be |
| came out, they were very heavy, slow and expensive, | | | | adjusted in order to filter signals for more or less |
| and their batteries were very large and heavy. Today | | | | sensitivity of interference or undesired transmissions. |
| there are also home based models available, and they | | | | |