TDOA with a Kraken or Kerberos

This is a little out of left field since the Kraken and tracking software is so much more robust. Going mobile with all the gear on the rig isn’t always possible. Here in the PNW rain is frequent and these antennas I bought with the device aren’t very waterproof. I’ve tried setting the system up on my second floor bonus room but found it works but not very well compared to being mobile.

A fellow ham mentioned he was going to get an rtl-sdr and use an Android device for DF work. It made me think of using two sdr’s and TDOA for tracking. I did a little Google searching and found this site . I have multiple Pi’s using sdr’s for tracking weather balloons, so maybe one of those could be dedicated to DF work. That’s when I thought about just using my Kraken here in the house, stretching all four antennas out as far as they go and use the TDOA app for mapping the signals I already have the pi that is dedicated to the Kraken, all I’d need to do is pop in a new SD card with the TDOA. Has anyone one tried anything like this or do any of you developers see any pitfalls? I know its not near as good as going mobile with Kraken app running. I have a KN2C DF2020 but the mappng software for that device requires you to be moving at least 3mph for the GPS to interface with the Doppler app.
Appreciate any suggestions of advice.

For TDoa you need stations positioned over many kilometers, not just a few meters.

Most TDoA projects with RTL-SDR also require some sort of sync signal. Often it’s DAB/DVB-T or GSM. But you need to set it specifically for whatever sync signal you have locally that can be received by all stations.

If you just want to use the KrakenSDR with a stationary antenna setup, why not use


I guess I have not explored the map feature of Krakenrf, my bad! I just registered and logged into it and it looks like that’ll be a serious tool. I suspect I’ll be hauling my case up from the garage.

I did realize for TDOA to work accurately some distance was needed to triangulate a location. My first DF purchase was the Ramsey DF-1 which uses TDOA. Thats why I was thinking something could work using 4 sdr’s with several meters separation compared to the 18" of spread on the Ramsey. I only used it a few times and quickly realized I needed something more serious for DF work.

Thanks for pointing me to the map! I think there is at least one person around the city with a Kraken, I need to find the others.

The Ramsey DF-1 works on the principle of pseudo-doppler, not TDoA.

TDoA is when you have stations separated over many kilometers, like 10’s to 100’s of kilometers apart, only then can you measure the time of arrival delta between signals. Look into what the KiwiSDR does with TDoA. Since they have users with stations spread all over the world, they are able to determine the location of HF transmitters.

For coherent and doppler methods you’re measuring the phase between signals which is zooming a bit further into the timescale.