I made a script to use the Digi XBee Cellular devices as NTRIP servers to transmit correction data to an NTRIP caster. Source is available on Github.
Currently running the script on a 3G XBee, however the same script should work on 4G devices (though I recommend LTE Cat 1, not LTE-M/NB-IOT, as they might not have sufficient data throughput). Unfortunately the LTE Cat 1 devices are only available for US bands so I have not been able to test with these yet. So far no problems encountered transmitting all MSM4 messages at around 550kB/s for the last 8 hours. Definitely seems to be a viable option.
I am also working on an ESP32 based XBee module for WiFi/Bluetooth interface, would anyone else be interested in it?
that is a brilliant idea and thank you for sharing.
However a lot of F9P Enthusiast (like me 🙂 might also be interested in doing the exact opposite, meaning to use the Xbee 3G/4G as a ntripclient and receive RTCM 3.2 Messages from a caster. This would drastically reduce the necessary space for a rover setup and likely be more rugged than current external computer clients.
There is some ntrip client py code flying around: https://github.com/jcmb/NTRIP/blob/master/NTRIP%20Client/NtripClient.py
Regarding your idea with the ESP32 – WEder has already implemented a smooth ntrip client into an ESP32, also providing Bluetooth serial data accessibility:
Another Austrian already sends RTCM Streams from the F9P to RTK2GO via an ESP32, but I haven’t seen the code yet ^^.