Video of my SDR Trunking setup, why doesn't it work?

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blipton

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Not 100% sure what I'm looking for, but at least in SDR#'s waterfall, I do see what looks like the continuous P25 control transmission described over on the rtl-sdr tutorial.
RTL-SDR Tutorial: Following Trunked Radio with Unitrunker - rtl-sdr.com

Unfortunately, despite the seemingly strong signal, when I open unitrunker, and park to that frequency, nothing happens! Shouldn't Unitrunker show a Site window containing all the control traffic.

Here's a video of what I'm seeing:
https://streamable.com/q95pt

I'm using a single RTL-SDR, and have tried tweaking the correction, drift, gain settings, but no luck. I also tried different park frequencies that show activity in SDR#.

Even if no one is using it, doesn't a trunked system broadcast some information that Unitrunker can pick up?
 

KE5MC

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The link to the tutorial seems complete. You open unitrunker and park on the frequency. No indication that you did any of the unitrunker setup to the point that you hear the control channel audio. I noticed unitrunker has a start button like SDR#. It could be as simple as pushing start. :D

Mike
 

frazpo

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Your video is kind of small. Do yo have your PPM correction set right? The signal health is showing 0. The wave signal is also showing no pattern for a good signal.
 

blipton

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Thanks, it seems part of the problem is how close my antenna is to the window! I moved everything close to the window, and now I see the "site" popup window activity!

The only problem is that I still don't hear any communication. I've got DSDPlus running in the background, and it looks like it has digital waveforms on it, but shouldn't there be audio output? Not sure if I have to first select a row in Unitrunker, but I tried several and nothing happens. There some that say 'enc' which I assume are encrypted?

https://gfycat.com/HarmoniousFemaleChimneyswift
 

SCPD

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Thanks for sharing the video. I see two problems.

1. The DSD+ scope pane has 3600 bps control channel data. Don't send the control channel to DSD+. Set the Voice role receiver's Park frequency to zero. 868.7 happens to be a control channel on another site.

2. All the calls in the video are "enc" which is encrypted.

The DB shows some non-encrypted groups but you may have to wait for such calls to appear.

RadioReference.com - Scanner Frequencies and Radio Frequency Reference Database
 
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mtindor

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Not 100% sure what I'm looking for, but at least in SDR#'s waterfall, I do see what looks like the continuous P25 control transmission described over on the rtl-sdr tutorial.
RTL-SDR Tutorial: Following Trunked Radio with Unitrunker - rtl-sdr.com

Unfortunately, despite the seemingly strong signal, when I open unitrunker, and park to that frequency, nothing happens! Shouldn't Unitrunker show a Site window containing all the control traffic.

Here's a video of what I'm seeing:
https://streamable.com/q95pt

I'm using a single RTL-SDR, and have tried tweaking the correction, drift, gain settings, but no luck. I also tried different park frequencies that show activity in SDR#.

Even if no one is using it, doesn't a trunked system broadcast some information that Unitrunker can pick up?
One thing -- Please disable "Filter Audio" under the audio section and never turn it back on again... at least not if you are going to be trying to monitor any digital transmissions. "Filter Audio" might work on 3600 baud moto type Ii control channels, but as soon as you go to monitor a P25 9600 baud control channel or NXDN or DMR etc you will be screwed.

Disable "Filter Audio"

Mike
 

blipton

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Thanks for sharing the video. I see two problems.

1. The DSD+ scope pane has 3600 bps control channel data. Don't send the control channel to DSD+. Set the Voice role receiver's Park frequency to zero. 868.7 happens to be a control channel on another site.

2. All the calls in the video are "enc" which is encrypted.

The DB shows some non-encrypted groups but you may have to wait for such calls to appear.
Thanks, not sure if this is what you meant, but I verified that the first VCO (Signal Role) is muted and has the Audio Output set to my speakers. The Digital Output is Unspecified.

The second VCO (Voice Role) has both the Audio and Digital Output set to Cable Input (VB-Audio Virtual).

However, when I set the second VCO from a Park frequency of 868.7001 to 0, the DSD+ waveform stops and the 2nd scope tab and RSSI/Window rows freeze. Strange, why does this tutorial's show the Voice park has to be the same as the control?
The Easy Setup Guide for RTL-SDR Trunking with One USB Dongle | ULTRA TechLife


Also, there doesn't even seem to be any static audio... the Svc column sometimes shows Dig, I assume I should highlight that row, but what is supposed to happen? Is there anything on the DSD+ application that I should be configuring? All I've done is put lame_enc.dll in the same folder, and execute DSPlus.exe prior to opening Unitrunker.. is this correct?
https://gfycat.com/LinearBewitchedEastrussiancoursinghounds


Thanks!
 

blipton

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One thing -- Please disable "Filter Audio" under the audio section and never turn it back on again... at least not if you are going to be trying to monitor any digital transmissions. "Filter Audio" might work on 3600 baud moto type Ii control channels, but as soon as you go to monitor a P25 9600 baud control channel or NXDN or DMR etc you will be screwed.

Disable "Filter Audio"

Mike
Thanks, and I can't seem to find where to disable the Filter audio. Is that a special window or in the main windows tab (VCO)?
 

SCPD

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Thanks, and I can't seem to find where to disable the Filter audio. Is that a special window or in the main windows tab (VCO)?
Mike didn't see your second video. He was pointing out a common mistake with audio sourced from SDR#.
 

SCPD

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when I set the second VCO from a Park frequency of 868.7001 to 0, the DSD+ waveform stops and the 2nd scope tab and RSSI/Window rows freeze.
As they should when there is no call to follow. For the program to point the second VCO to a voice call, that call must ...

a) be an analog, P25, or ProVoice call that is not encrypted.
b) be close enough to the control channel on the other VCO that both channels fit within the usable bandwidth of the SDR.

The only way to escape restriction (b) above is to add a separate SDR.

Strange, why does this tutorial's show the Voice park has to be the same as the control?
No idea.

Also, there doesn't even seem to be any static audio...
You won't hear anything in between calls. To hear static, set the analog output to your speakers.

the Svc column sometimes shows Dig
The "Dig" calls are eligible - provided restriction (b) does not prevent the second VCO from following the call.
 

blipton

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The "Dig" calls are eligible - provided restriction (b) does not prevent the second VCO from following the call.
Thanks, if the DSD+ Source Audio shows activity, would this be an indicator that I should be hearing audio?
I occasionally see waveforms on the blue screen, but no audio out... I can't help but think there is something wrong with my setup.. this is my first time doing anything with ham/sdr .

I've tried dozens of Park Frequencies on VCO#1, with lots of non-enc rows.. and the other .bat files in the DSD+ folder seem to be for decoding via internet.

Any suggestions what else I can try?
 

SCPD

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Thanks, if the DSD+ Source Audio shows activity, would this be an indicator that I should be hearing audio? I occasionally see waveforms on the blue screen, but no audio out...
Yes. Post an image or video of the waveform while a call is active.
 
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