Elektor was looking for some ideas regarding their STM32 Design Contest - and so I thought, why not putting the excellent work of the guys behind the RadioLib to good use and getting this board working in LoRaWAN (and it was easier than I thought :)):
https://www.elektormagazine.com/labs/getting-lorawan-working-with-stm32wl55-and-radiolib
Hi Nico,
Thank you for sharing your work. Great job on getting the rak5146 to work back when the documentation was limited. On that topic, I am starting with lorawan and I am having a hard time to decide which gateway to go with. I want to implement tdoa and rssi geolocation for tracking cattle on a farm. To do this I need at least 3 tdoa capable gateways at an affordable price (kerklink and cisco are obviously out of the question). The RAK5146 seem to be the obvious answer but still a bit pricey for a feature that MIGHT work.
My questions is, did you experiment at all with the fine timestamping feature of your rak gateway?
I see that elecrow has sx1302 concntrator and a very attractive RPI gateway hat at a combined price of only $40. The hat has GPS and real time clock. I wonder if this combo will be capable of the tdoa tracking.
Hi Dean,
sorry I have not tried TDOA yet. As far as I understood you'll need an SX1303 chip (e.g. RAK5146) for that to work, as it needs the "fine timestamp" for TDOA to be calculated: https://www.thethingsnetwork.org/docs/lorawan/concentrators/
I also found a post which mentioned the functionality could be used with Chirpstack - https://forum.chirpstack.io/t/how-to-configure-my-gateway-to-use-its-fine-timestamp-feature/17292 - however, did not try it.
But it hints that it might work using the chirpstack concentratord-sx1302 backend with e.g. RAK5146 (GNSS enabled). I am still a bit confused why the repo is called SX1302 - because the RAK5146 does not use an SX1302 and looking at the documentatino from TTN above SX1302 does not support fine timestamp and so it should not be able to get it working at all with anything on the SX1302 site...
Edit: Got it, the backend is just called SX1302 because it support SX1302 and SX1303 - https://www.chirpstack.io/docs/chirpstack-concentratord/hardware-support.html#sx13023
But there is another site that confirms SX1302 concentrators are unable to do this fine timestamps, so you will not be able to use the elecrow concentrator with it: https://forum.chirpstack.io/t/fine-timestamp-in-chirpstack-for-dragino-dlos8/16558/4
So, looking at SX1303 concentrators, it looks like the RAK5146 seems to be the best choice right now, I only saw one other concentrator from Heltech ( https://heltec.org/project/ht1303/ ) - which seems to be quite bad because it has no GPS/GNSS included (at least it looks like it) and has an PPS input which seems to support my suspicion... And without GPS/GNSS you can't use Fine Timestamps so, ... yeah. Looks like RAK5146 is the way to go, even though this will be costly (but not as costly as Cisco ;)).
Best of luck! 🙂
Hi Nico,
Thank you for your thorough reply I really appreciate it. I had the same sx1302 confusion as most sites talk of only sx1303 having fine timestamping feature but then the odd forum that suggests otherwise. On the rak forum velev mentioned that sx1303 and sx1302 could be used as long as there is GPS.
https://forum.rakwireless.com/t/reading-location-from-helium-network-instead-of-gps/5951/8
I think that is the reason why we see GPS and real time clocks on the SX1302 versions of the pi hat. But since there is little documentation supporting this I will rather play it safe and go with the more expensive Rak5146.
Thanks again
Most welcome and I hope you are successful in your endavours :).