FM Receiver doesn't work

GNU Radio
#1

Hello,
My system: WBX motherboard, B100, 2007 Macbook Pro 10.8.5 2.4 ghz core
duo 4gb 1067mhz ddr3.

I am new here. I have tried to build several FM receiver flow graphs -
Taken from the Ettus website, Ettus Youtube page and other sources too.
I get the same problem every time… no signal past the wbfm receiver. I
am convinced it must be something with the wbfm receiver block. Ettus
tech support guys had me investigate sample rates and WX vs QT
components, so I reduced sample rates as much as possible and ran both
WX and QT configurations with no change.

I’ve gotten simple flow graph examples to output audio and every block
that I’ve tried seems to do something except wbfm receiver. The Ettus
guys were able to run my flowgraph (with audio output from wbfm
receiver) when I emailed it. I just updated everything on macports and
the issue still persists. What can I be doing wrong? I won’t attach a
file until someone asks me to, since I’m not familiar with etiquette.
Thanks,

Stephan Vanwoezik
[email protected]
www.trapadulli.com
Delray Beach, FL 33444
(310)210-3814
Stephan Vanwoezik
[email protected]
www.trapadulli.com
Delray Beach, FL 33444
(310)210-3814

#2

On Wed, Feb 19, 2014 at 12:46 AM, stephan vanwoezik
[email protected] wrote:

change.
[email protected]
www.trapadulli.com
Delray Beach, FL 33444
(310)210-3814
Stephan Vanwoezik
[email protected]
www.trapadulli.com
Delray Beach, FL 33444
(310)210-3814

What version of GNU Radio are you running (check with
gnuradio-config-info -v). There was a bug that crept in to the
fast_atan2f function (it was my fault and I’ve been seriously
regretting it…) in the latest release that was fixed about a week
after it was introduced. The symptoms are most noticeable when
receiving low power FM signals since you get all 0s out.

See this thread for more details:
http://lists.gnu.org/archive/html/discuss-gnuradio/2013-11/msg00514.html

Nathan

#3

On 02/19/2014 07:46 AM, stephan vanwoezik wrote:

WX and QT configurations with no change.
Can you see an FM spectrum (using a QT GUI Frequency sink behind the
USRP source block)?

I’ve gotten simple flow graph examples to output audio and every block
that I’ve tried seems to do something except wbfm receiver. The Ettus
guys were able to run my flowgraph (with audio output from wbfm
receiver) when I emailed it. I just updated everything on macports and
the issue still persists. What can I be doing wrong? I won’t attach a
file until someone asks me to, since I’m not familiar with etiquette.

Thanks for being polite about this! In general, you can attach small
files. For GRC, screenshots are sometimes useful, and should be posted
to an image hosting service, such as imgur. Long text output goes onto
pastebin.

Martin