The KrakenSDR is a phase-coherent SDR five RTL-SDRs inside. This allows for RF Direction Finding. I heard people say that accuracy under worst conditions is 20-50m. But not knowing what they mean by "worst conditions", I thought of something I think is nearly impossible, but would be a very interesting experiment... Can it track Public safety via Trunked P25?
So first things first... This might get sketchy, especially if it works, but I just want to explore the possibilities. I don't intend on any unlawful activities.
So Digital Trunked P25 Phase 1 works by using a control channel to give orders for listening radios to tune to a trunked frequency when their selected talkgroup is active. So by listening to this frequency and decoding it with either SDRTrunk, Unitrunker, DSDplus, or other software, we can then get the following information...
Radio ID of talking radio (must be identified already, look at RR wiki, or listen for yourself), Base Frequency ("repeated" signal from towers), Mobile Frequency (radio to tower frequency, short range).
With that basic info, KrakenSDR should have what it needs to do some direction finding. The KrakenSDR will use Control Channel info to listen for a target Radio ID on the Mobile Frequency if it is in range. It wont be perfect, but a highway patrol officer relaying speeding car info should be an ideal scenerio.
Things to consider... radio transmissions are usually short, under 4 seconds and they arent too frequent. So not only do we have to be close, but we have to be there at the right time.... So what if instead of a car mounted KrakenSDR, there were multiple fixed units across town and they work together, not only do you disperse the receiver for greater coverage, but you also can spread out the antennas for greater accuracy.
What do you guys think? would it work to some degree?
So first things first... This might get sketchy, especially if it works, but I just want to explore the possibilities. I don't intend on any unlawful activities.
So Digital Trunked P25 Phase 1 works by using a control channel to give orders for listening radios to tune to a trunked frequency when their selected talkgroup is active. So by listening to this frequency and decoding it with either SDRTrunk, Unitrunker, DSDplus, or other software, we can then get the following information...
Radio ID of talking radio (must be identified already, look at RR wiki, or listen for yourself), Base Frequency ("repeated" signal from towers), Mobile Frequency (radio to tower frequency, short range).
With that basic info, KrakenSDR should have what it needs to do some direction finding. The KrakenSDR will use Control Channel info to listen for a target Radio ID on the Mobile Frequency if it is in range. It wont be perfect, but a highway patrol officer relaying speeding car info should be an ideal scenerio.
Things to consider... radio transmissions are usually short, under 4 seconds and they arent too frequent. So not only do we have to be close, but we have to be there at the right time.... So what if instead of a car mounted KrakenSDR, there were multiple fixed units across town and they work together, not only do you disperse the receiver for greater coverage, but you also can spread out the antennas for greater accuracy.
What do you guys think? would it work to some degree?
