| Hi All,
We have been using the USRP1 with the WBX card on it to communicate with the AO-51 satellite. We are expecting to hear from
the satellite using an Fm Receiver GRC at 435.300 MHz but don't receive anything as yet, we are pretty sure about our antenna setup and the GRC are right. The problem though is a spurious spike of about 17db which appears at whatever center frequency we tune to in the spectrum. we think that this might be the problem as that might be jamming the signal which was supposed be about the same db level. The point of notice for us is that this spike is always there even without the antenna connected. the fft is directly the output of the usrp source in the grc so, we are presuming that the problem might be in the usrp motherboard . Attached is the screenshots FM receiver spectrum. Did anyone have this
problem? How can we fix it?.
Thanks, Naveen | 
fm_spec.png