Hello,
I’m doing a spectrum sensing project and I’m testing both the USRP 1
and USRP 2. So far, I’ve modified usrp_scectrum_sense.py to do use
the USRP2 with the WBX
Right now I’m doing this is what I’m doing with what gr_bin_statistics
gives me (as discussed in a previous post)
signalPower=0
const =
20math.log10(tb.fft_size)10math.log(tb.power/tb.fft_size)
for bin in m.data:
signalPower += 20*math.log10(bin/tb.fft_size) + const
I then save each of the signalPower variables to a file and plot them
using matlab. The attached is what I get when I plot, this is the
results of one sweep with the USRP2 and WBX. I have several questions
about my results.

There are harmonics at multiples of the sampling frequency (100
MHz) which I have pointed arrows at. Has anyone encountered this
before? Are there any solutions? 
This sweep was done with a constant gain (31) on the WBX. Should I
be changing the gain as a function of the frequency I’m scanning? I
ask because after 1.5 GHz power seems to decrease quickly. 
In this sweep I had a terminated all ports with 50 ohm terminators,
so I would expect my sweep to be fairly flat. However, there peaks
and troughs. Does anyone know how I could get a flatter response?
Any help is appreciated,
Devin