Dynamically adjust SF for node

Hi everyone,

I got a TTN gateway a couple of months ago, as well as two boards to evaluate the system and to play around with. Now I wanted to see what the maximum range is in my environment (urban) and so I set the node to OTAA and programmed it to send a message every couple of minutes. Everything works fine, but the device sticks to SF8 and looses connection once I’m a couple of hundred meters away.

Now here comes the questions: When I want to dynamically adjust the SF the device uses, is this something that my node has to handle or is this automatically negotiated with the gateway? And if I have to do it, how is it done in LMiC? I couldn’t find anything in their documentation (only in the ABP example from their repository where you could hard code the SF to be 12).

Thanks for any hints!
Marco

Is it even possible?