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Location:
Finland
Registered:
June 2002
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Re: listening to Police on scanner radio
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Sun, 28 July 2002 10:04
 
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Many years ago I heard of a guy who re-tuned an old 450MHz frquency band mobile telephone for a specific job. (This was a bulky & hefty mid -80's car phone you more or less permanently install in a vehicle).
Fact: all receivers in the world generate a very miniscule radio frequency carrier wave leakage. Depending on numerous factors, this can be detected.
For example in United Kingdom the BBC requires all people watching TV's to pay an annual fee for television services. Some people don't pay. What BBC does, is they send 'detection vans' to patrol the streets. Equipment in those vans can detect this miniscule leakage a TV set radiates. They can even tell what channel they are watching.
This is exactly how the Police find out people having radar detectors. They have equipment to sniff oscillator leakage transmitted by radar detector.
Some radar detectors are not 'visible' to the Police. This is just because manufacturer had gone their way to alter electronics inside the detector, and the oscillator leakage is moved to some other frequency that the Police is unaware of. Knowing where it is, it too could be detected.
Test this yourself.
Switch on your home stereo receiver, tune it to whatever frequency. Take your VHF scanner radio, tune that exactly 10,7MHz higher frequency. You'll hear a carrier wave hum. That will vanish as you turn off your home stereo.
Back to the story.
This one radio amateur had converted this old 450MHz mobile phone to listen to police radio equipment oscillator leakage. Whenever this device 'went off' ,he knew there is a police patrol car nearby.
Pretty clever 'eh ?
My few first experiments have shown my scanner radio to be too insensitive to pick weak signals at longer distances. To help in minor speeding instances, I should sniff the coppers maybe like 200 to 300 meters away. Right now it seems not feasible.
Well, should give some warning when overtaking an unmarked Police car (or when they approach from behind) with this insensitive setup I have now.
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| | Subject | Poster | Date |
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listening to Police on scanner radio
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5KinKP60 | Tue, 16 July 2002 15:23 |
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Re: listening to Police on scanner radio
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Cool1 | Tue, 16 July 2002 23:33 |
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Re: listening to Police on scanner radio
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GIN51E | Thu, 18 July 2002 04:42 |
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Re: listening to Police on scanner radio
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justcallmefrank | Wed, 17 July 2002 02:29 |
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Re: listening to Police on scanner radio
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Cool1 | Wed, 17 July 2002 03:19 |
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Re: listening to Police on scanner radio
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Redline | Wed, 17 July 2002 07:01 |
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Re: listening to Police on scanner radio
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Lucid | Fri, 19 July 2002 03:34 |
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Re: listening to Police on scanner radio
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EVOSTi | Sun, 21 July 2002 11:31 |
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Re: listening to Police on scanner radio
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Toby AE82 Twin | Thu, 18 July 2002 04:16 |
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Re: listening to Police on scanner radio
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Cool1 | Thu, 18 July 2002 07:22 |
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Re: listening to Police on scanner radio
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manipulate | Thu, 18 July 2002 09:09 |
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Re: listening to Police on scanner radio
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GIN51E | Thu, 18 July 2002 09:43 |
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Re: listening to Police on scanner radio
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Cool1 | Thu, 18 July 2002 09:47 |
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Re: listening to Police on scanner radio
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manipulate | Thu, 18 July 2002 15:47 |
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Re: listening to Police on scanner radio
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Cool1 | Fri, 19 July 2002 01:15 |
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Re: listening to Police on scanner radio
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BigWorm | Sun, 21 July 2002 13:02 |
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Re: listening to Police on scanner radio
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EVOSTi | Mon, 22 July 2002 11:52 |
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Re: listening to Police on scanner radio
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Singlecam | Sat, 27 July 2002 06:29 |
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Re: listening to Police on scanner radio
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Cool1 | Sat, 27 July 2002 07:59 |
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Re: listening to Police on scanner radio
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GIN51E | Sat, 27 July 2002 10:38 |
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Re: listening to Police on scanner radio
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5KinKP60 | Sun, 28 July 2002 10:04 |
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Re: listening to Police on scanner radio
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Cool1 | Sun, 28 July 2002 10:11 |
