# Problems with Packet Encoder - Packed to unpacked - Unpack k bits - Packet Decoder **URL:** \ **Category:** GNU Radio\ **Created:** [May 16, 2014, 5:56pm UTC](https://www.ruby-forum.com/t/problems-with-packet-encoder-packed-to-unpacked-unpack-k-bits-packet-decoder/241185 "2014-05-16T17:56:56Z")\ **Posts on this page:** 1\ **Page:** 1
**Author:** ![musicdenotation](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ea666f/32.png) [@musicdenotation](https://www.ruby-forum.com/u/musicdenotation)\ **Post date:** [May 16, 2014, 5:56pm UTC](https://www.ruby-forum.com/t/problems-with-packet-encoder-packed-to-unpacked-unpack-k-bits-packet-decoder/241185/1 "2014-05-16T17:56:56Z")
Hi everybody, I’m currently working with some modulations (M-QAM, M-PSK) and my results are almost the same for all of them. I’m sending a wav file which is a 4 minutes song and in reception I get just few seconds of the song and with cuts. It seems that I’m losing lots of packets in the process. After try lots of things, I reduce my graph to the minimum eliminating all the mod/demod modules, as you can see in the attached picture. So at this point I’m getting the same results that I explain before and because of it I’m thinking that my problem is not in the mod/demod part of the graph and I think that they are in the use of the blocks: Packet Encoder - Packed to unpacked - Unpack k bits - Packet Decoder. The graph is: WAV FILE SOURCE -\> PACKET ENCODER -\> PACKED TO UNPACKED -\> UNPACK K BITS -\> PACKET DECODER -\> WAV FILE SINK As far as I know, these blocks do the following operations: PACKET ENCODER: Convert float samples into bytes, each byte with 4 symbols of 2 bits each. PACKED TO UNPACKED: Put a symbol of 2 bits in a byte in the MSB position. UNPACK K BITS: The opposite of “Packed to unpacked” block. PACKET DECODER: The opposite of “Packet enconder” block. Please, I would appreciate any help with this. I don’t know what I’m doing wrong. Thanks in advance!! Ramiro Utrilla