[Discuss-gnuradio] (WBX+USRP) Unknown signal at the middle of any FFT plot in receive mode

[jan acosta]

Hello,

I am currently testing two USRP radios with 3 WBX transcievers.

When I test the receive path, I would use gnuradio companion and go from USRP source to FFT plot.

However, I see that at every center frequency of the FFT window there is a signal even though I am not inputting anything.

The signal power is about 0 dBm.

Also, if I inject a signal, the power of the signal is shown to be much higher than the true power I am sending through.

For example, when I send a -50 dBm signal it shows up to be +30 dBm and I've tried using multiple signal generators.

So now I'm stuck.  

How do I fix this?

Thank you.