Re: [Discuss-gnuradio] still no luck with FM reception on 4937

[Matt Ettus]

Quoting Anastasopoulos Achilleas <address@hidden>:

>
> As I mentioned in a previous email,
> using the "tv_wfm_rcv.py" from the latest tarballs
> I get an error when decim=250 saying
>
> usrp_standard_rx::set_decim_rate: WARNING rates > 128 result in incorrect
> gain.

Ignore that in this case, and leave it at 250

> I also put an FM antenna (from my HiFi) at the 4937,
> and changed the which_side to 1,
> but still I do not get anyting out of it (other than noise).
> All I see in the pre-demodulation fft is a spike at 0,
> which I can burry in noise if I increase the gain more that 30dB.

Set the gain near about 60, and make sure you put the station frequency you want
in the command line.

> I get two warnings which I think are not related to the problem:
>
> ./tvrx_wfm_rcv_gui.py:34: FutureWarning: hex/oct constants > sys.maxint
> will return positive values in Python 2.4 and up
>   src = usrp.source_c (0, decim, 1, 0xf0f0f0f0, 0)
> ./tvrx_wfm_rcv_gui.py:36: FutureWarning: hex/oct constants > sys.maxint
> will return positive values in Python 2.4 and up
>   src = usrp.source_c (0, decim, 1, 0xf0f0f0f2, 0)

Ignore those warnings

> Also, when I touch the bottom ruler (the one that controls the offset)
> at the gui interface I get the message (which I think is also not
> related to my problem):

The DC offset is not used in this one because we are sampling at IF.  Don't
bother with that slider.

> At this point I will start testing the standard Tx/Rx to make sure
> everything works fine there.

That's a good idea.  Try hooking up a signal generator to the BasicRX and
running usrp_fft.py

Matt