Direction of Arrival approximation for 2.4 GHz transmitters

Discuss KerberosSDR - 4x Coherent RTL-SDR
Post Reply
InvertingOpam
Posts: 1
Joined: Mon Jan 13, 2020 12:24 pm

Direction of Arrival approximation for 2.4 GHz transmitters

Post by InvertingOpam » Tue Jan 14, 2020 7:45 pm

I have been playing with my kerberosSDR for a few months now and it has been a great learning experience. I have been thinking if this same process can be replicated at 2.4Ghz wifi frequency to detect the direction of wifi networks or 2.4Ghz rf remote controller. If I were to have a 4 chohorent sdr rx tuned ar 2.4GHz will this be replicable?

rtlsdrblog
Site Admin
Posts: 2563
Joined: Mon Nov 19, 2012 11:54 pm

Re: Direction of Arrival approximation for 2.4 GHz transmitters

Post by rtlsdrblog » Wed Jan 15, 2020 5:32 am

Yes it certainly could work at 2.4 GHz too, if the coherent hardware support was there for that frequency. Kerberos can only go up to ~1.7 GHz so that's a no go.

It may be possible to use Kerberos at 2.4 GHz with a downconverter. As long as the 4x downcvonerter clocks are all shared with one another it should work.

WiFi could be difficult though, because (correct me if i'm wrong) I believe WiFi packets are interleaved on a channel with time slots, meaning that it would be difficult to differentiate one transmission from another without looking at the WiFi packet data itself. Another issue is that the short bursts of packets make DFing difficult. If you could guarantee one device only on a channel, and sufficient packets to saturate the channel, then it would be easier.

oldark
Posts: 2
Joined: Thu Feb 06, 2020 2:41 pm

Re: Direction of Arrival approximation for 2.4 GHz transmitters

Post by oldark » Thu Feb 06, 2020 3:04 pm

Did you have any success with using a downconverter? I'm also working on a direction finding project that wants 2.4GHz capabilities. Kerberos worked great for us as a proof of concept but none of our team are very familiar with this space so trying to convert it to work with HackRF radios for higher frequencies hasn't been going well.

rtlsdrblog
Site Admin
Posts: 2563
Joined: Mon Nov 19, 2012 11:54 pm

Re: Direction of Arrival approximation for 2.4 GHz transmitters

Post by rtlsdrblog » Thu Feb 13, 2020 2:50 am

oldark wrote:
Thu Feb 06, 2020 3:04 pm
Did you have any success with using a downconverter? I'm also working on a direction finding project that wants 2.4GHz capabilities. Kerberos worked great for us as a proof of concept but none of our team are very familiar with this space so trying to convert it to work with HackRF radios for higher frequencies hasn't been going well.
Havn't been able to test a downconverter proto yet sorry. It's quite a time consuming project to build a 4-tuner downconverter prototype, unfortunately I don't have the time to commit to that investigation right now.

oldark
Posts: 2
Joined: Thu Feb 06, 2020 2:41 pm

Re: Direction of Arrival approximation for 2.4 GHz transmitters

Post by oldark » Thu Feb 27, 2020 2:27 pm

I understand. We also ditched the option since from what I can tell we'd need separate downconverters made for each frequency range of interest. Ideally we'd use a Kerberos that was put together with HackRF's instead of RTL-SDRs but so far my searching along those lines haven't yielded any fruit.

rtlsdrblog
Site Admin
Posts: 2563
Joined: Mon Nov 19, 2012 11:54 pm

Re: Direction of Arrival approximation for 2.4 GHz transmitters

Post by rtlsdrblog » Fri Feb 28, 2020 3:53 am

oldark wrote:
Thu Feb 27, 2020 2:27 pm
I understand. We also ditched the option since from what I can tell we'd need separate downconverters made for each frequency range of interest. Ideally we'd use a Kerberos that was put together with HackRF's instead of RTL-SDRs but so far my searching along those lines haven't yielded any fruit.
With a HackRF you could look into "Opera Cake", which is DIY hardware that will allow it to be used as a doppler DFing unit.

Post Reply