I am trying to capture a RFID Reader-Tag Conversation at 866.3MHz. I'm testing 2 cards: A FLEX 900 and a DBSRx rev2.2. With the FLEX900 i'm able to clearly see the Reader signals and the tag replies, but with the DBSRx the signals showed distorted by some higher frequency signals.
Using usrp_fft.py with the same settings and USRP/Antennas at the same exact position what I surprisingly saw was that the DBSRx is capturing an image of the RFID spectrum 400 kHz away!
What could this mean? Is something on the front-end damaged?
Here are the two screenshots of usrp_fft.py. one for FLEX 900 (good one) and one for the DBSRx (problematic)
http://twitshoot.com/1fhttp://twitshoot.com/1g