No RTK FIX with RTK2B F9P despite NTRIP connection

[dl7oap]

What is the bug or the crash? What were your expectations and what actually happened?

Despite an active NTRIP connection, the ArduSimple RTK2B F9P does not switch to an RTK FIX but remains stuck on a DGPS FIX.

The Issue #7521 looks not to be fixed in all circumstances

Steps to reproduce the issue

• Starting QField Version 4.2.6
• Open "Settings" > "Position" and connect to the RTK2B F9P via BLE
• Enable NTRIP Connection

you will see

• BLE Connection is running and positions are coming from the RTK2B F9P device
  • first as a 3D-FIX
  • later it will switch to DGPS-FIX
• NTRIP Connection is running (blue dot and download/upload rate is positiv)
• waiting for 5 minutes no RTK FIX or RTK Float will happen, but NTRIP Connection stays on blue dot

with "swmaps app" it is working with no problems. there i have a RTK Fix within seconds

Version

Qfield 4.2.6

Operating system name

iOS

Operating system version

ios 26.5.2 on a iphone 15

Reinstall QField

• I have a fresh install of the latest QField version, but the problem persists.
• Problem can be reliably reproduced, doesn't happen randomly.
• Problem happens with all files and projects, not only some files or projects.

Additional context

The Problem occurs with NTRIP Service:

1. openservice-sapos.niedersachsen.de, Mountpoint VRS_3_4G_NI, NTRP Revision 1.0
2. RTK2GO.COM, different Mountpoints, NTRIP Revision 1.0

If it helps, I’d be happy to generate a "QField application log" again and email it.