# Error using Packet Encoder --\> Packet Decoder

**URL:** <https://www.ruby-forum.com/t/error-using-packet-encoder-packet-decoder/242059>\
**Category:** GNU Radio\
**Created:** [May 23, 2015, 5:53am UTC](https://www.ruby-forum.com/t/error-using-packet-encoder-packet-decoder/242059 "2015-05-23T05:53:51Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**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 23, 2015, 5:53am UTC](https://www.ruby-forum.com/t/error-using-packet-encoder-packet-decoder/242059/1 "2015-05-23T05:53:51Z")

</div>

Hello everyone,

I want to simulate file transmission using BPSK modulation, with block  
diagram

File Source --\> Packet Encoder --\> BPSK Mod --\> BPSK Demod --\> Packet  
Decoder --\> File Sink

But the result is 0 kB. Then I remove the Encoder-Decoder and Modulation  
block.

File Source --\> File Sink

Then I have the file and it’s operable (-5 bytes from original file)

Next step I add Packet Encoder - Decoder

File Source --\> Packet Encoder --\> Packet Decoder --\> File Sink

But the file size is 0 kB

I don’t know what is wrong with the Encoder-Decoder.

Thank you

Regards, Surya A.

---

<div class="post-metadata">

**Author:** ![Surya\_A](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/8e7dd6/32.png) [@Surya\_A](https://www.ruby-forum.com/u/Surya_A)\
**Post date:** [May 23, 2015, 6:38am UTC](https://www.ruby-forum.com/t/error-using-packet-encoder-packet-decoder/242059/2 "2015-05-23T06:38:49Z")

</div>

Have you set the preamble and access code? The “leave blank for  
automatic”  
didn’t work for me.

Laur  
23.05.2015 6:53 kirjutas kuupäeval “Surya A.”  
[removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid):

---

<div class="post-metadata">

**Author:** ![Surya\_A](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/8e7dd6/32.png) [@Surya\_A](https://www.ruby-forum.com/u/Surya_A)\
**Post date:** [May 28, 2015, 1:22am UTC](https://www.ruby-forum.com/t/error-using-packet-encoder-packet-decoder/242059/3 "2015-05-28T01:22:13Z")

</div>

I try different “random” access code and preamble but the output still  
0kB.  
Would you mind to give an example or reference about it?

On Sun, May 24, 2015 at 2:09 AM, Surya A. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
wrote:

> > For testing whether it works, just set them to a bunch of 1-s and 0-s.  
> > the relevant Wikipedia articles for relevant articles 😃
> > 
> > > access code = blank
> > > 
> > > > > I don’t know what is wrong with the Encoder-Decoder.  
> > > > > [Discuss-gnuradio Info Page](https://lists.gnu.org/mailman/listinfo/discuss-gnuradio)

–  
Sincerely,

Surya A.  
University Al Azhar of Indonesia, Jakarta