Signal drought

Hi,
I built all the code today using the build-gnuradio script and when I
create a simple GRC flow graph going from the USRP source to the
waterfall plot, I get no data coming in. I then built gqrx and ran it
and it too doesnt get any data in from the device to display on its
waterfall. I ran the rx_samples_to_file example and captured some data,
but when looking at it in a hex editor, it doesnt look like it captured
anything in particular (http://test.utr-software.com/sdr/rxdump.dat). I
ran it with ./rx_samples_to_file freq=107700000 rate=1000000
file=~/rxdump.dat.

I am new to gnu radio and sdr so Im not yet sure how to dig in to debug
these issues.

Anything help is greatly appreciated.

Thanks,
Greg

On 05/05/2014 07:52 PM, Greg Hulands wrote:

Hi,
I built all the code today using the build-gnuradio script and when I create a
simple GRC flow graph going from the USRP source to the waterfall plot, I get no
data coming in. I then built gqrx and ran it and it too doesnt get any data in
from the device to display on its waterfall. I ran the rx_samples_to_file example
and captured some data, but when looking at it in a hex editor, it doesnt look
like it captured anything in particular
(http://test.utr-software.com/sdr/rxdump.dat). I ran it with ./rx_samples_to_file
freq=107700000 rate=1000000 file=~/rxdump.dat.

I am new to gnu radio and sdr so Im not yet sure how to dig in to debug these
issues.

Anything help is greatly appreciated.

Thanks,
Greg

How about something really, really simple:

uhd_fft -a type=b200 -f 107.7e6 -s 1.0e6 -g 40 --fft-rate 8 --averaging


Marcus L.
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org

It just looks like noise.

It just looks like noise.

Well, “noise” isn’t the same as “no signal at all”.

Do you expect there to a signal at 107.7MHz? Do you have an antenna
plugged in to the correct port on the device?

Thanks,
http://www.sbrac.org


Discuss-gnuradio mailing list
[email protected]
https://lists.gnu.org/mailman/listinfo/discuss-gnuradio


Marcus L.
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org

I changed antennas and I see a signal now in uhd_fft. I just noticed that when
in GRC and I run the flow graph, i dont see the RX light come on the board like
when running uhd_fft.

I have put the grc file up here http://test.utr-software.com/sdr/test.grc

Thanks,
Greg

The default antenna port if you don’t specify one is always TX/RX –
because you might be wanting to do half-duplex. You can explicitly
specify
the RX2 antenna port in the GRC source block, or just remember that
“unspecified” means, typically, TX/RX.

I am new to gnu radio and sdr so Im not yet sure how to dig in to debug these
issues.


Discuss-gnuradio mailing list
[email protected]
https://lists.gnu.org/mailman/listinfo/discuss-gnuradio


Marcus L.
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org

I changed antennas and I see a signal now in uhd_fft. I just noticed
that when in GRC and I run the flow graph, i dont see the RX light come
on the board like when running uhd_fft.

I have put the grc file up here
http://test.utr-software.com/sdr/test.grc

Thanks,
Greg


Discuss-gnuradio mailing list
[email protected]
https://lists.gnu.org/mailman/listinfo/discuss-gnuradio

I changed to RX2 and still not activating the receiver on the board.

Try changing the “Wire Format” to complex-int16


Discuss-gnuradio mailing list
[email protected]
https://lists.gnu.org/mailman/listinfo/discuss-gnuradio


Discuss-gnuradio mailing list
[email protected]
https://lists.gnu.org/mailman/listinfo/discuss-gnuradio

On 05/05/2014 09:11 PM, Greg Hulands wrote:

Just use a subdev spec of A:A

Are you getting any error messages when you run the graph?

I just worked it out - the run parameter in the Options block was set to
Off instead of autostart. Doh.

Thanks so much for your help. I really appreciate it.

Cheers,
Greg

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