Unitrunker One Voice Channel Out of Range

[BTJustice]

I use Unitrunker 1.0.33.6 with an Airspy Mini piping audio through VB-Cable being decoded by DSD+. Everything seems to work fine except for a voice channel out of range of the control channel.

I am listening to a system with 851.8875 as the Control channel and these for the voice channels:

851.3625
852.4125
852.9375
853.4625
858.3375

Is there a way for Unitrunker to tune 858.3375? I can see activity on it in Unitrunker, but cannot hear anything since I assume it is out of the bandwidth of the control channel.

 

[GTR8000]

The Airspy Mini has a maximum bandwidth of 6 MHz. 858.3375 is 6.45 MHz away from the 851.8875 control channel, putting it out of range. You're not going to be able to cover the entire spectrum of that site with a single Airspy Mini.

You could upgrade to an Airspy R2, which has a maximum bandwidth of 10 MHz, and thus would cover the entire site with a single dongle.

Or you can spend a lot less money and buy a good quality $25 TCXO RTL dongle, such as the NooElec NESDR SMArt, using that as the signal receiver parked on the control channel, and have the Airspy Mini setup as a separate voice receiver.

You could also ditch Unitrunker in favor of the latest Fast Lane release of DSDPlus, which can run in single-dongle mode. That would allow any dongle to cover the whole site, as it will leave the control channel to tune to voice calls, making the spacing between frequencies irrelevant.

 

[slicerwizard]

^^^ What he said. It's all good info.

Also, why so cagey? You've provided more than enough information to identify the statewide network and the specific site, so what's the point...

Also, your problem frequency - 858.3375 - isn't listed in the RR database for that site. Are you sure it's correct and not just a bad decode? Maybe you already have enough RX bandwidth.

 

[BTJustice]

Would the Airspy R2 work? If the Mini has 6 and R2 has 10, isn't that's just to the sides of the control frequency? So at best, 3 with the Mini and 5 with the R2. The R2 still wouldn't cover it by itself then right?

Guess I will have to use an old RTL-SDR for control as you suggested.

I'm not interested in FL DSD+ when there is already free software to do the job. The DSD+ website lacks information to compel me to be interested in FL DSD+.

Yes that problem frequency is valid and used.

 

[GTR8000]

Would the Airspy R2 work?

You could upgrade to an Airspy R2, which has a maximum bandwidth of 10 MHz, and thus would cover the entire site with a single dongle.

 

[BTJustice]

But that doesn't make sense when all the online documentation seems to indicate it is parked (centered) on a control frequency and monitors voice frequencies. If control is in the middle then it would make sense it could only do 5 to the left and 5 to the right. And it is a heck of a gamble to shell out $169 + shipping for an Airspy R2 to find out it still doesn't work.

 

[GTR8000]

Then use an RTL dongle for control and the Airspy Mini for voice. Problem solved.

 

[BTJustice]

Just finished setting that up. Working well so far.

 

[Unitrunker2]

Beware the usable bandwidth is about 80% of the sample rate. That's 8Mhz usable for the R2 vs. 4.8 MHz usable for the Mini and 2 MHz usable for a Realtek SDR.

Usable bandwidth for the HackRF is more like 75%.

 

[Unitrunker2]

. If control is in the middle then it would make sense it could only do 5 to the left and 5 to the right.

The program uses a sliding window. As long as both channels fit inside the SDR's usable bandwidth, it should work.