SparkFun GPS-RTK2 Board messages enabled over UART2 but no data

I am trying to enable message F1-00 PUBX00 to output on UART2 which I have connected via bluetooth. I also enabled the message over USB. If I connect via USB I can see this message in U-Center but I don’t when connected via bluetooth. I do receive the default NMEA messages over bluetooth just fine but can’t seem to modify the message output for this channel. Any suggestions?

Hi Danny,

I am afraid I am not familiar with the message you are trying to enable here and this is getting a bit beyond the scope of SparkFun’s Tech Support. I cannot find it in any of the documentation we have on the [ZED-F9P Product Page. Can you please provide the documentation you are following to enable this message? One thing I found in the [datasheet is it appears no UBX protocol is supported on UART2 (section 5.1). That might be the issue here but if you can point us to the documentation you are following for the “F1-00 PUBX00” message, that would help us possibly identify the issue here.](https://cdn.sparkfun.com/assets/8/3/2/b/8/ZED-F9P_Data_Sheet.pdf)](SparkFun GPS-RTK2 Board - ZED-F9P (Qwiic) - GPS-15136 - SparkFun Electronics)

Thanks for the reply Mark. The documentation clarifies the issue for me. The message is indeed a UBX protocol I was trying to read. Incidentally, I thought I could use the UART2 for this type of communication because of the following quote from your GPS-RTK2 Hookup Guide. “Additionally, but less often needed, the UART2 can be configured for all types of communication including NMEA output, and UBX binary protocol communication.” I will reconfigure my setup to use the UART1 port instead. Thanks for the feedback

Hi again Danny,

Ah, that’s a good catch! I will notify our tutorials team about that error and we’ll get that fixed to clarify that UART2 has a few limitations.

Apologies for reviving an ancient thread but just want to leave a comment regarding non-RTCM data over the UART2 port. We have two SparkFun GPS-RTK2 (ZED-F9P) modules with one configured as base and the other as rover. When configuring the rover to receive RTCM corrections over bluetooth (BlueSMiRF) it works fine as far as getting to a 1.73 cm FIX as confirmed in u-Center. Those RTCM corrections are sent to the rover F9P module via the Lefebure NTRIP client app from our base sending over SNIP mountpoint.

The problem however is transmitting NMEA sentences back over bluetooth (UART2) to the Lefebure NTRIP client app so that it can display the current status (RTK; Lat/Lng, etc) and also using the phone as a mock GPS location for recording ground control points. We had UART2 in u-Center configured as expected on the rover (RTCM in, NMEA out, GGA being sent to UART2 and USB, baud 115200, NMEA child messages enabled, etc). We could see the GGA msg’s being sent over the Packet Console (USB) every second however bluetooth/UART2 was not transmitting them. After searching countless boards and threads, this discussion is the closest we could find to someone hitting a similar problem with UART2. Long story short, we switched from UART2 to UART1 and voila the NTRIP client was pulling them in over bluetooth, displaying Lat/Lng, RTK Fix, etc on the Android app.

If anyone out there encounters this problem with NMEA over UART2, switch over to UART1 and you should be ok. Note that if you were previously counting on UART2 to filter out non-RTCM messages, which is nice, you may need to update your caster and/or u-Center settings so UART1 only has RTCM incoming and NMEA out. If you were using UART1 as an SD card logger (OpenLog) port you can switch over to the Qwiic OpenLog as an alternative.

@SkyHorseTech Thank you so much for sharing this! I am encountering the same challenge with my ZED F9P not pushing my lat/long back to the Lefebure NTRIP client app.

How exactly do I switch over to UART1? I have a ZED-F9P configured as a rover, connected to the Sparkfun Bluetooth mate. I am running these from an arduino with a bunch of other sensors attached via qwiic connectors, with an external battery.

I tried plugging the ZED-F9P back in to the computer and reconfiguring it in U-Center (I went to configuration view → PRT (ports) → select UART1 from the dropdown menu and set it to RTCM3 in, NMEA out), but this didn’t seem to solve anything. I think I am not actually successfully switching to UART1 to be able to output NMEA via bluetooth.

Fortunately I have a UNAVCO site nearby, so my Lefebure app is configured to receive one of their data streams . There doesnt seem to be any way in the app to update the settings for that caster.

Any further details you can provide on what you did would be much appreciated!