Thanks for the tips!
I was a bit confused with the concept of packet, It is much clearer now.
I took your advices. I have, now, a simulation that works, at least for
dbpsk. ( dqpsk and d8psk, still give odd output).
Just to let the GNUradio community know. My final aim is to realise a hf
transceiver that use the STANAG 4285. I will keep you in touch.
ps : I may have double post. If so, my appologies