Problem with OTA capture examples

GNU Radio
1

Hi,
I’m working through the examples on this site:

http://www.kd7lmo.net/ground_gnuradio_ota.html

and am trying to run this code:

http://www.kd7lmo.net/gnuradio/am_rcv.py

If I run this in the terminal:
./am_rcv.py hf_10000khz_256_complex.dat 0
I get this:
bash: ./am_rcv.py: Permission denied

Anyone have any idea what I’m doing wrong?

Thanks,
Peter

2

The same thing happens when I simply copy a file in the
~/gnuradio-examples/python/audio directory, give it a new name and try
to run it.

3

On Wed, Dec 17, 2008 at 03:47:57PM +0100, Peter O’Doherty wrote:

Peter
You need to ensure that the script is executable.

$ chmod +x am_rcv.py

Eric

4

On Wed, Dec 17, 2008 at 04:26:57PM +0100, Peter O’Doherty wrote:

audio_alsa_sink[hw:0,0]: set_period_time_near failed: Invalid argument
RuntimeError: audio_alsa_sink

Can you please try using google before asking your questions here:

google:

audio_alsa_sink[hw:0,0]: unable to support sampling rate 32000

Thanks,
Eric

5

Thanks a lot. That does the job.

But now I get this message:

len(channel_coeffs) = 795

gr_fir_ccc: using SSE
len(audio_coeffs) = 51

gr_fir_fff: using SSE
audio_alsa_sink[hw:0,0]: unable to support sampling rate 32000
card requested 44100 instead.
audio_alsa_sink[hw:0,0]: set_period_time_near failed: Invalid argument
Traceback (most recent call last):
File “./am_rcv.py”, line 105, in
main (sys.argv[1:])
File “./am_rcv.py”, line 98, in main
fg = build_graph (filename, freq_offset_khz)
File “./am_rcv.py”, line 78, in build_graph
audio_sink = audio.sink (int (audio_rate))
File “/usr/local/lib/python2.5/site-packages/gnuradio/audio_alsa.py”,
line 236, in sink
return _audio_alsa.sink(*args)
RuntimeError: audio_alsa_sink

So I guess correcting the adc_rate to 88.2e6 solves the sampling rate
error:

len(channel_coeffs) = 1095

gr_fir_ccc: using SSE
len(audio_coeffs) = 69

gr_fir_fff: using SSE
audio_alsa_sink[hw:0,0]: set_period_time_near failed: Invalid argument
Traceback (most recent call last):
File “./am_rcv.py”, line 105, in
main (sys.argv[1:])
File “./am_rcv.py”, line 98, in main
fg = build_graph (filename, freq_offset_khz)
File “./am_rcv.py”, line 78, in build_graph
audio_sink = audio.sink (int (audio_rate))
File “/usr/local/lib/python2.5/site-packages/gnuradio/audio_alsa.py”,
line 236, in sink
return _audio_alsa.sink(*args)
RuntimeError: audio_alsa_sink

But what about the audio_alsa_sink error?

Thanks again,
Peter

6

Okay sorry. I did try a search on Nabble but it didn’t come up with any
results.

Please bear with me for one last question:

Changing the command to
./am_rcv.py hf_10000khz_256_complex.dat 0 -O plughw:0,0

Just returns:
usage: am_rcv_file {file_name,‘usrp’} freq_offset_KHz

But this seems to be exactly the imput I’m giving it. What am I missing?
Many thanks,
Peter

7

On Wed, Dec 17, 2008 at 06:04:57PM +0100, Peter O’Doherty wrote:

But this seems to be exactly the imput I’m giving it. What am I missing?
Many thanks,
Peter

You’ll have to look at the code to figure it out.
We don’t maintain that particular piece of code, and it doesn’t appear
to implement our standard argument parsing conventions.

Eric