I have a the XLR stacked onto the F9P the lights on the F9P show msgs coming in but the RTK is intermittent. I tried switching to MSM4 and turning off Diebou constellation as I was wondering if the telemetry was over loaded. The problem didn’t change.
Did you get the simplertk2b with the high power xbee power? The regular ones apparently don’t have enough power for the XLR.
I have the XLR. I THOUGHT I had switched to MSM4. I waited till I had changed all messages before saving. 
I am now running MSM4 sand I haven’t had an issue in 1/2 hrs.
Which version of simplertk2b do you have? Is it the one that can supply enough power for the XLR?
I’m trying to decide how to tell the difference… I don’t know if I got the high power one…
Looks like it’s the Pro version
I’m sure you could add an external 3.3v supply to beef it up.
Interesting I had to read it twice to catch that “high power” thing….