[Discuss-gnuradio] USRP N200, RFX 1800 not receiving signal

[Urs Hunkeler]

Hi,

My USRP N200 / RFX 1800 combination seems to not receive any useful 
signal. The software seems to work, there are no error messages, and the 
USRP seems to sample noise but does not even show a signal from a signal 
generator.

Has anybody an idea what I might be doing wrong, or what else I could try?

I use Ubuntu and installed/compiled the latest GNUradio / UHD software. 
I used the uhd_fft.py script to test the radio. I tried different 
frequencies, both antennas and different transmit power level on the 
signal generator (-110dBm - -10dBm). The only thing I see is noise, 
which changes slightly when I change the gain.

The command to start uhd_fft.py was:

uhd_fft.py -A RX2 -f 2G --samp-rate=16M

The output of uhd_usrp_probe is:

--------------------
linux; GNU C++ version 4.4.3; Boost_104000; UHD_003.002.001-fd33faa

-- Opening a USRP2/N-Series device...
-- Current recv frame size: 1472 bytes
-- Current send frame size: 1472 bytes
  _____________________________________________________
 /
|       Device: USRP2 / N-Series Device
|     _____________________________________________________
|    /
|   |       Mboard: USRP-N200
|   |   rev: 2560
|   |   mac-addr: a0:36:fa:26:30:30
|   |   ip-addr: 192.168.10.2
|   |   gpsdo: none
|   |   serial: E3R10Z0UN
|   |
|   |   Time sources: none, external, _external_, mimo
|   |   Clock sources: internal, external, mimo
|   |   Sensors: mimo_locked, ref_locked
|   |     _____________________________________________________
|   |    /
|   |   |       RX DSP: 0
|   |   |   Freq range: -50.000 to 50.000 Mhz
|   |     _____________________________________________________
|   |    /
|   |   |       RX DSP: 1
|   |   |   Freq range: -50.000 to 50.000 Mhz
|   |     _____________________________________________________
|   |    /
|   |   |       RX Dboard: A
|   |   |   ID: RFX1800 (0x0034)
|   |   |     _____________________________________________________
|   |   |    /
|   |   |   |       RX Subdev: 0
|   |   |   |   Name: RFX1800 (0x0034)
|   |   |   |   Antennas: TX/RX, RX2
|   |   |   |   Sensors: lo_locked, rssi
|   |   |   |   Freq range: 1500.000 to 2100.000 Mhz
|   |   |   |   Gain range PGA0: 0.0 to 70.0 step 0.0 dB
|   |   |   |   Connection Type: QI
|   |   |   |   Uses LO offset: No
|   |   |     _____________________________________________________
|   |   |    /
|   |   |   |       RX Codec: A
|   |   |   |   Name: ads62p44
|   |   |   |   Gain range digital: 0.0 to 6.0 step 0.5 dB
|   |   |   |   Gain range fine: 0.0 to 0.5 step 0.1 dB
|   |     _____________________________________________________
|   |    /
|   |   |       TX DSP: 0
|   |   |   Freq range: -250.000 to 250.000 Mhz
|   |     _____________________________________________________
|   |    /
|   |   |       TX Dboard: A
|   |   |   ID: RFX1800 (0x0035)
|   |   |     _____________________________________________________
|   |   |    /
|   |   |   |       TX Subdev: 0
|   |   |   |   Name: RFX1800 (0x0035)
|   |   |   |   Antennas: TX/RX
|   |   |   |   Sensors: lo_locked
|   |   |   |   Freq range: 1500.000 to 2100.000 Mhz
|   |   |   |   Gain Elements: None
|   |   |   |   Connection Type: IQ
|   |   |   |   Uses LO offset: Yes
|   |   |     _____________________________________________________
|   |   |    /
|   |   |   |       TX Codec: A
|   |   |   |   Name: ad9777
|   |   |   |   Gain Elements: None

--------------------


Cheers,
Urs