I didn’t say that. I will infer that you are implying that you are inferring that I am implying that it is illegal under criminal law. I didn’t even suggest that it was illegal under civil law.
You may want to give some real serious consideration as to why the main GNU Radio wiki has no results when searching for LoRa.
There are indeed many plugins that do LoRa with an SDR with GNU Radio - but it’s not in the main repository and all the offerings are put in the context of being used for research purposes, not for replacing a few $$ worth of silicon that costs far less than any SDR but comes with an implied license for use of Semtech intellectual property.
Asking about an SDR implementation for research is one thing, but you said want to use it as a replacement for an actual device. Which is like phoning the police before you go out on a heavy drinking session in a country pub with the intention of driving home.
In these situations it’s not the right or wrong, it’s the weight of documentation that arrives in the post that you have to give to some one with the ability to draft a response that stops the follow up letters. That help is usually rather expensive.
Even if you try to reframe it for research purposes, the cat is out the bag now.
And if you can’t patch LMIC or LoRaMac-node over the top of the radio implementation, you are stuck with point 2 - which we would ask that you use a private LoRaWAN server for testing so as to not disrupt the TTN Community servers. There are only a limited number of people who will be able to help with questions on the internals you would need to implement.
To expand on this, this would only count if it was BladeRF GNU Radio to a LoRa device based on Semtech silicon.
Please don’t misunderstand, if you want to go on a voyage of discovery, great.
But if you just want to get some numbers from some unknown source that you haven’t specified, a sensor or serial or ModBus or whatever, there are many many many ways that can be implemented in a couple of hours this weekend with any of the Arduino based boards with a LoRaWAN stack.
Whereas writing your own stack will take some time. And potentially put you in a precarious position if you look to replicate it beyond your one “research” device.