Andreas, you mean the antenna for the rover or base?
At the moment I am testing in office: the base is a F9p at RPi and for the rover I use a m8t with rtknavi. So the rover is only L1. But I tried the Sapos-RTK as well and that gave me 13-17 sats and a stable fix. The fix of my own base is not so stable. Maybe the big, old oak 30 meters away is a problem. Until now I am not so happy with the reliability of the rtk fix. But MSM7 improved the signal a lot.
How can I find out if the antenna or its cable is sligthly broken?
Strangly I get a fix after a while, but then I loose it 10 minutes later and it doesn´t come back.
At the moment both base and rover antennas are very close to each other and rover doesn´t move.
I am not sure if I can rely my base now.