SDRSharp UniTrunker Support

8/25/13 SDRSharp UniTrunker Support

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ConfiguringUniTrunkerSupportinSDRSharp(ThispagepoweredbyMicrosoft Word!!!)

1 OverviewA trunked radio system is simply a system of radios in which the frequencies used are dynamically managed by a central controller. The rules andprotocols of operation vary by system, but in order to effectively listen to a trunked radio system, you must have the following:

- A receiver that is capable of receiving and decoding the trunking control channel(s) that issue commands to the participating radios.

- A receiver that is capable of being tuned automatically to the frequencies used by the trunked radio system for the calls/communicationof interest.

- If the trunked radio system uses digital encoding of voice communications, additional decoding ability may be required.

2 SDRSharpImplementationIn the present implementation for SDRSharp, the above requirements are delivered with the following components:

SDRSharp Provides radio support and routing of audio to desired output channelshttps://www.assembla.com/code/sdrsharp/subversion/nodes/branches/bobrichbinaries: https://public-xrp.s3.amazonaws.com/Release-latest.zipMicrosoft Visual C++ 2010 Runtime, which can be obtained here:http://www.microsoft.com/en-us/download/details.aspx?id=5555

UniTrunker Provides decoding support for trunking control channels and issuance of tuningcommands.http://unitrunker.com/

Virtual Audio Cable Provides audio routing between componentshttp://software.muzychenko.net/eng/vac.htm

Digital Speech Decoder (DSD) Provides digital voice decoding supporthttp://minus.com/msG44Ttxp/



2.1 DualReceiverConfigurationIn this configuration, one receiver is dedicated to receiving control channel information, the other is dedicated to receiving voice calls.

2.1.1 VirtualAudioCableVirtual Audio Cable may be obtained here: http://software.muzychenko.net/eng/vac.htm

A trial version is available and will functions reasonably well in this application. There is a periodic trial watermark uttered over the channel, butthe applications used to process these radio signals have fairly robust controls for handling noise. Obviously a registered version is the idealscenario.

Virtual Audio Cable should be configured as follows, two channels are required if digital voice calls will be decoded. Note that all audio isprocessed at 48kHz.

2.1.2 WindowsSoundSystemConfigurationIf DSD will be used, one of the VAC audio channels must be configured as the default recording device. For purposes of this document, we willselect Virtual Audio Cable Line 1 as that device:



2.1.3 UniTrunkerUniTrunker is available here: http://www.unitrunker.com/download/

Version 1.0.25.2 was used for most of the development of this process and works successfully. The latest version as of July 18th is 1.0.25.4 and willbe used for this document. No significant differences were noted.

2.1.3.1 Remote.dllNote: The Remote.dll requires the Microsoft Visual C++ 2010 Runtime, which can be obtained here:

http://www.microsoft.com/en-us/download/details.aspx?id=5555

The integration between SDRSharp and UniTrunker operates through the Remote.dll which is included in the AutoTuner SDRSharp binarydistribution (http://public-xrp.s3.amazonaws.com/Release-latest.zip) or may be built from the repository:



(https://www.assembla.com/code/sdrsharp/subversion/nodes/branches/bobrich/UniLogger?rev=478)

This remote.dll must be copied to the UniTrunker installation directory.

2.1.3.2 ReceiverConfigurationTwo receivers must be configured in UniTrunker, a Signal receiver used to receive the control channel signal, and a Control receiver used toreceive the voice channel transmissions. This can be a little confusing as the signal that the Signal receiver is receiving is typically called aControl Channel

2.1.3.2.1 SignalReceiverTo create the first receiver, click the large plus sign in the tool bar and select Signal

Select the appropriate Audio Port and Sample Rate for your Virtual Audio Cable configuration. If digital voice will be used, select the Virtual Audio



Cable port that is not the default recording device.

Close this window, and click the large plus sign again to create the Control receiver.

2.1.3.2.2 ControlReceiverSelect Control in the following dialog box, and configure as follows. Note: The receiver must be of Debug type or the remote.dll will not be



called and this contraption will not work:

The only other step generally required is to check the P25, ProVoice or VSELP boxes if you will be decoding digital voice on those channels. Notethat the trunking channels identify analog vs. digital, and UniTrunker will not tune this receiver to the correct frequency if digital modes are usedand the appropriate box is not checked. Im not aware of any downside to checking them all. (Note: This setting was not generally saved in1.0.25.2 of UniTrunker, so if you start it up again later and doesnt work, take a look at this setting)



Finally, in the main UniTrunker options screen, click the Enable checkbox in the Listen section:



2.1.3.3 SDRSharpSignalRadio

2.1.3.3.1 SignalRadioConfigurationBefore starting SDRSharp, open the sdrsharp.exe.config file and ensure this line is set as follows:

Once configured as such, start SDRSharp, change the Front End device if necessary, click Play and tune to the control channel of interest. (If you donot have a frequency, you should be able to find one by searching the spectrum in the 850-900MHz range, or consulting sites likeRadioReference.com). Ensure the mode is NFM and your filter bandwidth is set appropriately for the protocol (typically 12.5kHz). You should heara grinding/grating noise with reasonable volume and little spurious noise.

If that all checks out, click Stop, then scroll down to the Audio section. First, uncheck the Filter Audio box, then select the correct output audio



channel for your UniTrunker Signal receiver. Click Play again, and tab back to UniTrunker. Select each receiver and click the Play button in thetoolbar until it says Running.

Within 10 seconds you should see a window like this:

2.1.4 InitializingUniTrunkerWere about half way there

2.1.4.1 FrequenciesTuning will not happen without Frequencies populated in UniTrunker. If they do not auto populate, click the little calculator icon and select thecorrect band-plan for your setup. Typically standard works unless you know otherwise:



Note: If the wrong one is selected, it will be obvious when the radio is simply tuned to the wrong frequency.

Close this window, and the site window should now look like this:



2.1.4.2 PopulatingTrunkGroupNameswithRadioReference.com(optional)If you have a Radio Reference account, you can download the Trunk Group names by clicking the ship wheel and entering your credentials:



Once complete, you should be able to click Systems in the main UniTrunker channel and see something like the following:



Note the Groups should be populated with a reasonably high number (>50).

IMPORTANT: In my specific case, the groups are for system ID 6F16, but my site is 712D. This prevents my calls from being tagged with theappropriate trunk group. I Stop my signal receiver, delete the 712D system, then double click on the 6F16 system and change the ID to 712D. Closethat window, then re-start the receiver. This works.

The calls should now be tagged correctly:



2.1.4.2.1 ControlRecieverWith this in place, select the control receiver in the main unitrunker window and click Play to ensure it is running. Open the receiver, and scroll tothe bottom:



The Listen section should be dynamically updated with calls as they come in. If the Radio Reference support is not available, Target will simplybe the trunk group ID. If it is stuck in Park, then check to ensure the correct checkboxes are enabled above P25, ProVoice, VSELP, or just checkthem all.

The final step is to CROSS YOUR FINGERS and look in the UniTrunker home directory with Windows Explorer. You should see a small file calledsdrsharptrunking.log. This is the control file used to drive SDRSharp, and it should be getting updated with the information from the Listensection in the Debug receiver. If the file does not exist, make sure that remote.dll is in the home directory.



The content will look something like this:

action receiver frequency trunkgroup trunklabelListen Debug 867562500 3184 Madison Correctional primary control

2.1.5 SDRSharpControlRadioThis is where the second dongle comes in to play with this configuration.

Start a second copy of SDRSharp and select the correct front end. If you are using two RTL2832U dongles, the one in use will be skippedautomatically.

2.1.5.1 CalibratingtheTunerBecause this instance will be tuned programmatically, it is essential that the tuner be correctly calibrated (especially in the case of the RTL2832U). The simplest way to do this is to tune to the control channel frequency by typing the value into the Center Frequency and Frequency boxes. You may see something like this (zoomed in, minus the label in the spectrum analyzer unless youve also loaded a frequency CSV file in the autotuner section)

Note the control channel is wide left of the tune point. Click front end and adjust the PPM value in the bottom right until it is as perfectly centeredas possible:



(Note: You may need to scroll down to the Display section and bump up the FFT resolution (16k or so) to get a good idea of where the edges of thesignal are).

2.1.5.2 AnalogVoiceAudioConfigurationThere isnt much to do here. Ensure that the Output is set to your speakers. This copy of SDRSharp will attempt to save settings and this one willtend to overwrite between the two copies. Also, ensure filter audio is checked or youll get a bunch of extra noise.

2.1.5.3 DigitalVoiceAudioConfigurationFor this one, select the default recording device Virtual Audio Cable audio port. Ensure that Filter Audio is unchecked.

2.1.5.4 UniTrunkerConfigurationScroll down to the UniTrunker panel, check the box, click File and browse to the UniTrunker Install Directory.

NOTE: The code currently makes the poor assumption that youre running UniForm.exe directly from the install directory. If you run it from theshortcut, you will find these files in your %AppData% directory, typically C:\Users\\AppData\Roaming\UniTrunker. This is the folder youneed to select, and because it does not see UniForm.exe or Remote.dll in the same directory, it may complain. Ignore that.

Once these are in place, SDRSharp should start taking commands from UniTrunker and tune to the appropriate frequency. For analog voicechannels, nothing else should be required. For digital voice channels, additional work may be required to get DSD to decode properly.

2.2 SingleReceiverConfigurationIt is possible to do trunking with a single receiver, but with two caveats:

Digital Voice Only Not a technical limitation, but a practical one. Because all audio goes to a single output channel, the analog voice would be



mixed in with the digital control channel, which would only be bearable for a small amount of time. Fine for testing though.

Longer Delays Between Calls Because UniTrunker will not be getting control channel information while the radio is tuned to the voice channel, itwill require about 7 seconds of initialization time after every call.

2.2.1 ConfigurationThe configuration is essentially the same, except all of the SDRSharp configuration is done with the same instance of the application.

2.2.1.1 AudioAudio must be routed to the default recording device so that DSD will pick up the digital voice channels and UniTrunker will pick up the controlchannel on the same audio channel.

2.2.1.2 UniTrunkerLockModeConfigure the Lock Mode in the Signal Receiver to Dedicated or you will get AdHoc Site popups every time the tuner returns to the controlchannel

2.2.1.3 UniTrunkerControlReceiverConfigure the Park frequency to the control channel frequency (in MHz).

2.2.1.4 SDRSharpUniTrunkerPanelBecause UniTrunker loses the signal immediately after tuning to the voice channel, it will Park the control receiver. We must ignore this specificcommand or you will only get about a second of audio on each voice call.

To do this, click Delay Re-Tune checkbox, and set the (db) level to something midway between the noise floor and peak level of the voicechannel signals.



Checking Tune to Control Channel will cause this instance to tune to that frequency when no information is available from UniTrunker.

Documents

SDRSharp UniTrunker Support