Could it be a cell reception issue? When I check the towers map, the closest one is almost 5km away. It’s a Rogers tower. The closest Bell tower is like 8km away. Since it’s a gravel pit, maybe you’re too far below and get poor reception. Is the SIM card in the RS3 or in your phone? Might be worth a try to use the phone’s receiver instead of the Reach’s.
I had a similar intermittent issue with my Mavic 3 Enterprise drone where RTK was connecting and disconnecting.
It turned out that on occasion when I alternated between drones (on hot days to allow cooling between flights) I hadn’t powered down the other drone and they were both connecting to the base via NTRIP with the same account which only supports one connection.
Not sure how or if this translates to the RS3, but thought I would share it as another option to consider.
The site I’m at is almost exactly in the dead center of 3 of their Ref stations which are all far away since I am rural. Emlid Flow seems like it doesn’t know which one to choose or Topnet doesn’t know which one to assign to me.
I’ve connected to a unreliable, free RTK station that is very close. I’d never use their corrections for survey but just for testing and it stays FIX all the time.
Switching back to Topnet and the problem persists.
When we use the same service with Carlson their software seems to pick a station and stick with it.8