Hello LoRa enthousiasts,
I’m quite new to LoRa / TTN and the last few months I’ve been playing around with some hardware/software. Basically I built a node (Frank Beks,Creating a TTN node using a Pro Mini, and a few weeks ago also a Gateway based on a RPi 2 and IMST IC880 concentrator board. The good news is that everything is up, running, reliable and functional however…
OTAA joining on the TTN network does not work as expected. Joining the TTN network takes up to 15 minutes and I never get a faster / better join than SF11. I’ve seen quite some topics covering the problem I also experience, but the solutions that are presented don’t solve my issue nor I understand the real cause.
(I tried changing lmic.c file with DR_SF9 iso DR_SF7 and adding the LMIC_setClockError function without success.)
I also signed up for a developers account on the KPN LORA network and using exactly the same hardware/software (I only changed the DEVEUI, APPEUI and APPKEY) it joins flawless and within seconds using SF7. Everytime, every boot/restart. With this “knowledge” I can only conclude there is nothing wrong with the hardware/software used on the node.
As I had no TTN gateway reach nearby I decided to build a gateway myself. When I try to join the TTN using OTAA I can see the gateway receives all Join Request messages and also sends a Join Accept in return however the node does not seem to receive these Join Accept messages until the node starts sending SF11 messages. After sending the first SF11 Join Request message the Join Accept message is received and the join is succesful.
(It seems this node-behaviour is the same on other nearby (Eindhoven) TTN Gateways.)
I really hope someone can point out “the one thing” that I am missing or guide me in the right direction.
I have attached some screenshots:
Succesful OTAA KPN LoRa SF7 join:
Slow OTAA TTN SF11 join:
Gateway Traffic log during a succesful Slow join:
Thank you for looking into this topic!