what kind of digital signal is this

alex36917

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May 22, 2020
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This is for you tech people.

The fire/rescue dispatch went away from analog, so I need to buy a digital scanner. If it helps, the fire units use Motorola radios. Also, is it encrypted?
 

jhampton2000

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Dec 19, 2005
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It sounds like P25. You cant tell from a simple recording of audio like this if its encrypted or not.
 

alex36917

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May 22, 2020
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What is your location (City, County, State) and what agency are you trying to monitor? What model scanner do you have?
Thank you for your help, but I checked, and the database still says FM. They went digital just a few days ago. I'll just buy a used scanner with Phase I P25 and see if it works. Thank you also jhampton2000.
 

ecps92

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The DB may still say FM, because no one has noticed, or made a DB Submission

Once you have a radio capable of P25, make the needed submissions, it is from users only, that the DB grows
Thank you for your help, but I checked, and the database still says FM. They went digital just a few days ago. I'll just buy a used scanner with Phase I P25 and see if it works. Thank you also jhampton2000.
 

alex36917

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May 22, 2020
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How do you know it is phase 1? If you tell me what you want to monitor, I will check it out.
They don't use trunking, so I assume it's phase I (if I'm correct that Phase II is only used in trunked systems). Also, I can't find used P25 Phase II scanners. Thank you for your offer, but I already bought a scanner.
 

Reconrider

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Honestly, just spend the money for a p25 phase 2 scanner. No point to buy a phase 1 only scanner when it's only a matter of time before they go to phase 2.THey may even be already at p25p2.
You can't listen to p2 with a p1 scanner.
 

kj6psg

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Sep 1, 2012
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Ventura, CA, USA
It sounds like P25. You cant tell from a simple recording of audio like this if its encrypted or not.
There's a different sound to encrypted P25 as there's a much larger random component to the signal. This sample sounds unencrypted.

How do you know it is phase 1? If you tell me what you want to monitor, I will check it out.
All conventional P25 uses Phase 1. Phase 2 only exists in trunking systems. Phase 1 in C4FM, Phase 1 in CQPSK, and Phase 2 all sound noticeably different in both AM and FM demodulations. This is Phase 1 C4FM, so any simulcast issues (I don't hear any) wouldn't be correctable with a better scanner.
I do agree it's not worth getting a Phase 1 scanner anymore; the technology is about 15-20 years old and it doesn't cost too much more to be Phase 2 ready.
 

alex36917

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May 22, 2020
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Thank you, you guys sure know your stuff. Now I'll just have to try it out and see if it's encrypted.
 
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