Thanks a lot for the help. I am using linux ubuntu 18.04 operating system. When I want to use the uhd_packet_tx.grc example given in Gnuradio/examples/digital/packet folder, I see that a block is missing as can be seen at below figure(Example is taken from Gnuradio3.8 version). What is this block for? Do I have an uninstalled package? I am beginner in this area. If you help me, I am very pleased to you.
