SIRIUS F9P comparison with DP0601


I have been using DP0601 with Ublox ANN-MB and DA233 multiband antenna in RTK mode and these are working very well.
In good condition, the ZED-F9P rover can achieve +/-3cm accuracy with a fixed base.

As I wanted to have a more compact design, I evaluated the SIRIUS F9P that has an integrated antenna with the same ZED-F9P base in RTK mode.

First thing, the ZED-F9P rover configuration files generates some errors when trying to load them on the SIRIUS F9P. I think some forum’s thread deals with that issue.
So I tried to replicate my Rover setting on the Sirius F9P manually.

The configuration seems to work, checking with U_center, the Rover is indeed in RTK/FIXED after some times under same condition. I basically use a 433M Modem to transfer/receive the RTCM data.

However, under some circonstances ( shaking the rover or making some fast itinerary change) it seems that Sirius F9P goes more often in FLOAT rather than ZED_F9P with external multiband antenna under same circonstances. In my evaluation, I am holding both SIRIUS and ZED-F9P receivers at same time and separated from 50cm to ensure that satellites and environment conditions are similar.

Just wondering, Is there a FW setting or HW difference that may degrade the Sirius RTK behavior under fast directions or altitude changes versus the one of the original DP0901 ZED-F9P receiver?

Could the integral antenna performances of the SIRIUS receiver be different or lower than the D233 or ANN-MB antennas?