Introduction
Terms and Definitions
Frequency | Radio signals are sent as waves through the |
| air. These waves move up and down. A |
| frequency is the number of times in a certain |
| time period, usually a second, that these |
| waves move all the way up and all the way |
| down and back to all the way up. For example: |
| 123.44 kHz means that the waves are moving |
| all the way up and all the way down and back |
| all the way up again 123,440 times each |
| second. |
Mobile Extender | When highway patrol officers step away from |
| their cars, signals from the patrol car are sent |
| to their portable radios via a mobile extender. |
| The mobile extender is a transmitter/receiver |
| that receives the signal from the station and |
| transmits it to the portable radio on a different, |
| but lower, frequency. |
Scanning | Scanning is the process by which your |
| scanning radio looks for “activity” in the |
| channels it is programmed to look at. The |
| scanner checks each frequency for the |
| presence of a signal, and when it finds a |
| frequency with a signal, for example someone |
| talking on it, it stops, allowing you to listen to |
| the signal. The |
| System also looks for activity on mobile |
| extender frequencies. When the |
| detects the presence of a signal on one of |
| these frequencies, it will trigger an audio and |
| visual alarm. |
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