Re: [Discuss-gnuradio] bandwidths< 400Khz no longer work with USRP2

[Marcus D. Leech]

On 11/14/2010 02:28 PM, Marcus D. Leech wrote:
> I did a "git pull" for both UHD GnuRadio yesterday.  I'm on the "next"
> branch for gnuradio, and on
>   "master" for UHD.
>
> Since doing a rebuild yesterday, bandwidths below 400KHz no longer work
> on the USRP2.
>
> I did a test with a dead-simple flowgraph:
>
> UHD single source-->multi-const x 32767-->FFT
>
> For bandwidths>= 400KHz, the resulting FFT, with my existing RF
> front-end with 40dB gain feeding
>    the BASIC_RX on my USRP2, the FFT looks just fine (showing a level
> around -40dB).
>
> But anything below 400KHz bandwidth (I tried various bandwidths between
> 200KHz and 400KHz),
>    produces an FFT with nothing useful in it, and a "level" around -400dB.
>
> This used to work just fine below 400KHz. What happened?
So, nobody has answered my question yet.

Even with the "latest and freshest UHD (master) and GnuRadio (next)", Rx 
bandwidths below 400KHz don't appear to work correctly on a USRP2
  with UHD, giving a flat-line at -410dB in the FFT display.