help with sdr

[mattnelson26]

i was wondering if someone could help me on setting this all up i got to where i put my control channel in but the screen to see whats on the channel doesnt pop up.

thanks
matt

 

[br0adband]

Well first you need to provide some info:

- what SDR hardware do you happen to be using (something like SDRplay or Airspy or simple RTL USB sticks aka "cheap USB TV tuners" or what scanner(s)

- what kind of computer you're using (general info like CPU/RAM and what OS obviously)

- what SDR software you're attempting to use (SDRSharp, HDSDR, SDR-Console/Radio, or something else)

- since you mentioned a control channel I'd guess you're looking to monitor a trunked system so provide info about the system (city or whatever and potentially a link to the system on the RR database)

- whether or not you're trying to use additional software like DSD+ to decode digital protocols

Gotta provide some info before anyone will be able to help - just asking for help in general won't get you too far and forces someone else to have to ask you the questions I just did.

 

[mattnelson26]

sorry about that

i am using a RTL-SDR Receiver, RTL2832U & R820T Tuner

windows 7 Cpu 3.40ghz and 4.00 gb of ram

Sdrsharp

Allied Radio Matrix for Emergency Response (ARMER) Trunking System, Various, Minnesota - Scanner Frequencies Minneapolis City Center Simulcast

yes dsd+

i got to where you see whats on what control channel and the info screen doesnt popup.

thanks,
matt

 

[br0adband]

Now you're getting somewhere, but as I don't use DSD+ myself (haven't for some time) I'm sure someone else will provide some info soon enough, perhaps even DSDPlus will pipe in too.

 

[mrlindstrom]

If you are wanting to trunk follow the system you will need to use UniTrunker as DSD+ does not currently trunk P25 systems. You will still need DSD+ to decode the voice channels. If you watch my video starting from the point in the link below, it will show you how to set up Unitrunker for control channels and voice channels using 2 RTL USB devices. It is possible to use only 1 RTL device under certain conditions, but for the best results you will most likely need 2.

https://www.youtube.com/watch?v=RvCchqKSrZI&t=40m30s

 

[mattnelson26]

got my 2nd dongle. dsd shows audio but thats it was wondering if some would be willing to help me out now. have attach a screen pic

thanks,
matt

 

[br0adband]

Just a guess but taking a glance at that picture and primarily at the audio waveform displayed in the top left hand corner looks dreadful to me; I could be wrong about that but it doesn't appear to be anything you might actually be able to make any use of for a proper decode to audio. Perhaps adjusting the volume levels down a bit might help, and of course making sure all the variables in play are correct, most notably the ppm settings for the given RTL stick you're using for the signal source. Even a +/- 1 ppm adjustment - when coupled with proper audio levels - can make all the difference in the world with a P25 decode, at least that's been the case in my experience with DSD+ in the past.

Also as a tip for Unitrunker: uncheck every protocol that you're not actively making use of in the R820T receiver properties - it might not make any difference at all in terms of improving things but it sure can't hurt either. Same principle as you're already doing with DSD+ by telling it to listen for and decode only P25 content which makes it work a bit more efficiently.

 

[mattnelson26]

ok dsd was a flat line when nothing was happening but when it is active it shows. will try your tips. also i have teamviewer a remote control if anyone wants a closer look.

thanks,
matt