GFSK decoding errors

Hi guys,

I ran into an issue with the GFSK communication module, I send some text from a file and read the received text through a pipe to python.

In about 80% of the cases the bits get mixed up. For example, while sending the ‘UUUUUUUSTARTUUUUUUUU’ pattern I occasionally get it right, but most of the times something scrambled like ‘UUUUUUUTd510T9515UUUU’ or ‘UUUUUUUMQ05IQUUUUUU’ is received (I used the U letter since it’s an easy code to spot, it has the 01010101 clock code :slight_smile: )

Now, when I sample the raw bits before the “Pack K Bits” module and decode them manually, everything is received correctly every time! So the first guess would be some issue with the “Pack K Bits” module, but it works flawlessly in other configurations :confounded:

Any advice would be welcome :nerd_face:

Here is the image of the setup with two LimeSDR units: