SDRTrunk SDRTrunk OTA alias /\/\ system

[Bearded_Schnauzer]

I want to monitor a P25 Phase II system with FDMA control which I know SDRTrunk can do. However, can it also decode and display Motorola Group Services if its used by a subscriber radio?

Many agencies on this state system are using Group Services because.... well I see it on my work radio and I can also them on DSDPlus. I am trying to get this to work but I am not seeing any OTA aliases coming up. I suspect this is because I only have one RTL-SDR in use? Is the OTA alias set on the TDMA voice channel that would be decoded with a second RTL-SDR?

 

[rr60]

Exactly that. Group Service Aliases are on Voice Channels by the each, not the CC.

Look at your radio as the voice starts, note the label, the radio at that time is on the voice channel and not CC.

More SDR’s. Some software display, some do not, so as to avoid licensing issues with TDMA.

 

[dave3825]

I suspect this is because I only have one RTL-SDR in use?

What's the spread of the site your listening to? Post a link to it or take the lowest freq and minus it from the highest freq. Is the answer greater than or less than the dongles bandwidth?

 

[Bearded_Schnauzer]

Ok, got it. Group Services is on the TDMA VC which is why I am not seeing them since I am on the CC only.

 

[Bearded_Schnauzer]

I'll add another RTL-SDR and see what happens. I really like how DSDPlus works with OTA aliases from both Motorola and Harris but it doesnt run on linux/Rpi. SDR Trunk seems to be missing some of the filter/logging capability that DSDPlus and Unitrunker have.

I suppose each software package has its strengths. I'm just starting to explore so maybe I am missing some stuff.