The police scanner's story dates back to the early 1930s. The police would broadcast at a local AM radio station. Anyone who heard a radio with a radio. The traditional radio system is basically full of frequencies. The frequencies are the communication channels.
To listen to transmissions, certain channels have to be programmed into the scanner. The first type of police scanners were screened through four channels. To hear, you have to set a quartz crystal to the frequency and plug it into an internal slot. Each crystal cost about $ 7.00 and will ultimately be very expensive for maintenance. In the late 1970s, programmable scanners were invented. You have entered the frequencies on the keypad and the scanner memory saves all the frequencies. Then the trunk radio system came out and allowed you to track the five or thirty channels or frequencies. Location is where users are automatically assigned the frequencies. Just as emergency departments have a frequency, or truckers have another frequency. These types are more difficult to monitor because they often switch between channels during conversations.
Today is a digital channel scanner. This is a computer that encrypts the audio streams in the data streams and then decodes the buzzer to hear the audible sound. First Uniden was released in 2002, and in 2003 Radio Shack released the digital scanner. These are great to use because I can say things through the radio and can not be heard, only those who can decode what would be few people. The only person who decodes the codes is those who are programmed to the channel.
Police scanners are nice because they are something other than TV and radio. You can sit in the back yard and you can understand why the police stand on the road and you know something is going to be scary or something you should not think about. Police scanners are purchased because one person belongs to one of the emergency departments or just to the interest of the community.
There are often reports on a police scanner that was first broadcast before all the information. For example, a police scanner will first be informed about the tornadoes that the touchdown, or if the weather is over-interrupted before news releases the information. This kind of information came from the National Weather Service and is totally trustworthy. Police scanners can be just as entertaining as they are informative about all the dumb things people say in the air.
Source by sbobet