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General Scanning Discussion - For general questions not specific to a model of scanner or general discussion of use of a scanner. Manufacturer specific posts should be directed to the appropriate forums below and location specific posts should go in the appropriate regional forum..

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Old 07-12-2018, 5:50 PM
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Default trunked signals

I believe the noise I hear on a regular scanner are trucked signals ,some sound like a running diesel engine ,others like an gasoline engine ( revving up ) with a knock in it. I guess this is the data , but exactly how is this data hidden in these sounds.
I've heard digital signals before on the radio and they sound like data ,not a car or truck engine ?

What makes this data sound this way ... I am hearing it on an analog scanner.


Al
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Old 07-12-2018, 6:27 PM
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Quote:
Originally Posted by alok View Post
but exactly how is this data hidden in these sounds.
P25, DMR and NXDN use 4-level FSK (Frequency Shift Keying)
https://en.wikipedia.org/wiki/Frequency-shift_keying
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Old 07-12-2018, 7:19 PM
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What frequencies? There are a lot of digital signals that aren't trunked. When you say "running engine" sound, digital paging comes to mind.
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Old 07-12-2018, 8:51 PM
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This link may be of interest: Digital*Modes*Samples
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Old 07-12-2018, 9:07 PM
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Default computers

they can talk different languages.
and they all sound different to us.
1's and 0's look the same but don't sound the same.
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