Receive NMEA with UDP

I can't see NMEA sentences coming from UDP.
They are sent in this format $GPRMC,115848.00,A,5647.02820,N,01139.86570,E,4.0,121.0,100722,,,A*51
which works well on the PC with other programs like OpenCPN etc.
The port is set to 0.0.0.0/2000. I have checked that qtVLM opens the correct port when clicking on StartNMEA as it gets unavailable to other apps.
Any explanation?

Version : 5.10-16-p2 (meltemus) (Jul 14 2022)
System windows 11
Qt 5.15.9
Memory size: 16,242 Gb
CPUs: 8
Build for: x86_64
Running on: x86_64
screen size 1920x1080 *1

 

It should work, have you started NMEA?
--Philippe

Yes - I have clicked on Start NMEA and a black window opens. That's all I see.

I've clicked on StartNMEA and a black window shows up. That's all.

Normally this works out of the box.
Make sure you have not checked "'internal source"
Then you can try 255.255.255.255 as IP address, or the IP address of the sender; or the word "any".

I now see that there is a difference according to which application that is providing the UDP feed. I have coded two different Python scripts that generates NMEA strings that are transmitted over UDP, and one of those can be picked up in qtVlm. So to me it looks like qtVlm is expecting some kind of formatting of the sentences. Do you have a specification on how to format NMEA strings and what is expected (like checksum, line feed etc)?