What would be the accuracy of simplertk2b when the distance between base and rover is 50km? Corrections transmitted by NTRIP.
It is not an absolute.
uBlox recommends being within 10 Km, the specification suggests the CEP(50%) would be at least 6 cm radius at 50 Km
Real problem is differences in atmospheric path diminishes the “commonness” of the common error components you’re trying to remove. You’re also getting into curvature, and different satellites in view the further you separate the Base and Rover.
People would generally do tests to establish performance in their use cases, sort of thing that takes time/effort.
If you want better accuracy you should set up your own local infrastructure, and do a proper survey of your base antenna locations.