Why no police scanner for SDR? - Page 1
Forum section: electronics / rf-microwave

author: Beamin
author_rank: Super Contributor
timestamp: July 21, 2018, 04:18:53 am
content: When I got my SDR I thought it was magic! And would replace all my other radios but one it didn't: the trunking digital police scanner. For that I have to rely on my radioshack pro96 and to get the channel lists to put into the radio you have to pay radio reference $30.00 mainly because I dumped them by mistake.With all the stuff the SDR does why not a police scanner? Does the scanner use two receivers in tandem or some hardware limitation the SDR can not?

author: AG6QR
author_rank: Frequent Contributor
timestamp: July 21, 2018, 04:38:46 am
content: The scanner uses two receivers in tandem, one for the control channel and one for the audio.But the killer is that the codecs for most digital audio schemes are proprietary. In particular, most digital public safety systems in the US at least, use APCO P25. The license fee for the decoder is expensive.http://forums.radioreference.com/general-scanning-discussion/146947-why-digital-scanners-so-expensive.htmllikIn theory, perhaps it could be implemented in SDR, but you'd still have to pay the license fee, or risk a lawsuit. I don't know the full legal details, but my bet is the APCO folks can afford better lawyers than I can.

author: Bratster
author_rank: Frequent Contributor
timestamp: July 21, 2018, 04:40:37 am
content: I'm pretty sure I've seen a video or something that somebody made a trunking scanner with 2 Sdr receivers. Let me dig around and see if I can come up with it.1 receiver looked at the control Channel and the other receiver bounced around to the various trunking channels I think.Sent from my Fi Moto x4 using Tapatalk

author: Bratster
author_rank: Frequent Contributor
timestamp: July 21, 2018, 04:43:25 am
content: Here it is.https://youtu.be/g9KJrtIO8_4It doesn't do the encrypted channels as far as I can tell, but I don't know that your handheld scanner would do those either.Sent from my Fi Moto x4 using Tapatalk

author: Beamin
author_rank: Super Contributor
timestamp: July 22, 2018, 06:26:58 pm
content: Quote from: CopperCone on July 22, 2018, 02:57:45 pmYeah they can afford gun and fancy suits but are using a CB radio.Terrorist on CB: "Ze Police are here!"CB: "Fuck you fucking faggot liberal mother fuck fuck fucking krawt. This 'merica fag!."

author: darrellg
author_rank: Unknown
timestamp: July 23, 2018, 05:04:42 pm
content: Here's another YouTube how-to.https://youtu.be/tG_cgtoZcrY

author: josecanuc
author_rank: Contributor
timestamp: July 23, 2018, 08:27:39 pm
content: http://osmocom.org/projects/op25/wikihttps://osmocom.org/projects/op25/wiki/SignalScopePage#TRUNKINGcompletely open-source, SDR trunk-tracking. There is a low-volume yahoo group mailing list that seems to have the latest updates on instructions, which include a new way to get the thing running that doesn't depend on a GUI.It's not "easy" to set up, but once you have it going, it just runs. My install has been running for 7 months straight. Can pipe audio to local sound card, or over network.

author: Lord of nothing
author_rank: Super Contributor
timestamp: July 26, 2018, 01:21:13 pm
content: Quotebecause it illegal in the most country?

author: Beamin
author_rank: Super Contributor
timestamp: July 29, 2018, 10:27:30 am
content: Quote from: darrellg on July 23, 2018, 05:04:42 pmDo you think you can do something like that where you use multiple com ports so you can hear two programs at once such as decoding software and at the same time hear what you are doing? I have program that decodes various teletype messages over HF and you tune it with HDsdr or what ever software you are using but the problem is you can't hear it, so it's guess work and a lot of effort to find the right decoding without hearing the signal.I didn't realize the hack RF had two receivers in it. Also 299 is a lot better then 799 like it used to cost.

author: Lord of nothing
author_rank: Super Contributor
timestamp: July 29, 2018, 02:07:44 pm
content: There is an Plugin for SDR# who allow the Software to put out more than one Audio Stream at the Time. You need just an Virtual Soundcard who you create multiple channels.