Re: [Discuss-gnuradio] uhd_fft.py and USRP N210

[Marcus D. Leech]

Hi,

I was running uhd_fft.py on USRP N210 with TVRX2 daughter-board. I get mysterious peak at every 100 MHz center frequency i.e. 100MHz, 200 MHz, even though no antenna is connected. Please help me what is wrong.

Thanks you,

Rahul

Two things:

There is almost always an anomaly near DC, so it's often best to tune your target frequency so
  that it's away from DC in the baseband.  So, let's say your signal of interest is at exactly
  500MHz (just to use the example from problem.png), tune 50KHz away, 500.050MHz, so that
  DC appears outside your passband.


The clock oscilator on the USRP2/N2XXX is 100MHz, so there will be small spurs of this clock
  appearing, but which are usually easily drowned out once you put an antenna on the input.

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