SdrPlay with RTL2832 for P25 Trunking

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mswells

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I am trying to setup up P25 Trunking on my SdrPlay and RTL2832 dongle. I can get everything to work, but how to set up sdrplay to receive the p25 voice channels, and have my rtl2832 stay on the control channel ? I can see activity in unitrunker site screen, but no audio since sdrplay is not configured to have unitrunker send it the channel change commands.
I am using SdrSharp (1500), Unitrunker, Dsdplus, and VB Audio Cable for my config. I can see the activity in unitrunker, for the simulcast A site here in phoenix, but am not seeing how to send the commands from unitrunker...while monitoring the control channel with the Dongle....to tell sdrplay the correcty voice channels to follow.
 

nickajeglin

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Do you hear anything out of your speakers? Is debug the correct receiver type to use? I use two sdr sticks, so I have both my receivers set to RTL2832 for the type, and then I select the actual device ID from the RTL device drop down. I'm not familiar with the SDRplay, so that may not work for you. If I remember correctly, if the signal receiver and voice receiver are both running, unitrunker should tell the voice one to automatically tune to wherever the action is. Do you see anything happening on the scope tab of the voice receiver? Try outputting both analog and digital outputs to the virtual audio cable, changing your park frequency to something near where the broadcasts are, and see if you can get anything to show up in the scope.

Edit: I attached what mine looks like, just in case it will help you. You're in good hands with Mr. Unitrunker though, he was very helpful when I was setting mine up.
 

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nickajeglin

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I dug around a little, and it turns out that the SDRplay doesn't use the RTL chip, so my suggestion probably won't work for you. I'm probably doing more harm than good here, so I'll escort myself to the door.
 

SCPD

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First off, to simplify your set up, configure the Realtek USB stick to be controlled directly in Unitrunker. It can be voice or signal role - you just need to pick one.

To accommodate the SDRPlay, what I am about to describe is a bit of a Frankenstein of a set up. I don't recommend it but it may work for your specific situation.

The SDRUno software supports a serial port "rig control" protocol called CAT. Apparently a number of older Kenwood radios can be controlled by CAT. HDSDR also accepts CAT commands. In combination with a virtual serial port driver called com0com - SDRUno and HDSDR can accept commands from other programs to do things like tune to a specific channel.

Unitrunker supports dozens of serial port protocols - mostly Uniden, GRE, and older iCOM CI/V protocols. It does not speak "CAT" unfortunately.

A plugin exists for SDR# to accept AOR ONE commands (yet another "rig control" protocol). Unitrunker does support AOR ONE. Here's an example of someone using it:

article



In a nutshell, Unitrunker and CAT only programs like SDRUno and HDSDR don't know how to talk to each other.

The easiest thing to do is use the SDRplay as the source for the signal role discriminator input reciever. Use SDRplay to tune to an active control channel. Unitrunker can directly control the Realtek USB receiver to follow voice traffic.
 

mswells

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unitrunker step by step

still trying to get unitrunker setup wo use the sdrplay as the control receiver so it can send the commands to the rtl2832 to go to the proper voice channel, but am stuped on the step by step setup of unitrunker, as far as creating the control receiver, and the voice receiver, and setting up the com port on the ar one receiver. in the drop down I see a bunch of com 0's, and one com 2...when I use com 2 , and try running sdrsharp, it fails to open saying COM IN USE.
 
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