Usrp2 + wbx

Hello everyone,

I just got the USRP2+WBX recently. And I used the famous “usrp2_fft.py”
as a
starting point.

The problem I met is that the curve plotted by the usrp2_fft.py seemed
to be
abnormal. Sometimes, the amplitude of the curve was around -150 dB, and
sometimes it went below -400 dB.

An antenna was attached to the “TX/RX” port of the WBX.

I tried “usrp2_probe” and got the following information.

USRP2 Probe

MAC Addr:
00:50:c2:85

Name (ID):
1

Converter Rate:
100000000 Hz

Gain Range (min, max, step size):
0.0
0.0
0.0

Freq Range (min, max):
-90000000000.0 Hz
90000000000.0 Hz

It looks like to me the RF daughterboard was not properly configured.

Did anyone meet such a problem?

Also, I have another two questions:

For full-duplex communications, does it mean both “TX/RX” and “RX2” need
to
be attached to antennae? How to configure the WBX?

On “usrp2_fft.py”, if the center frequency was set beyond 206 MHz, it
would
prompt “Failed”. Why this happened? There was no such prompt using the
FFT
Sink on GRC.

Thanks.

-Evan

You probably need to load the SD card with the txrx_wbx.bin firmware:
http://gnuradio.org/releases/usrp2-bin/trunk/

-Josh

On Thu, May 06, 2010 at 06:12:33PM -0500, Evan Chen wrote:

90000000000.0 Hz

On “usrp2_fft.py”, if the center frequency was set beyond 206 MHz, it would
prompt “Failed”. Why this happened? There was no such prompt using the FFT
Sink on GRC.

Looks like maybe you are still using the default image on your SD card.

To use WBX with USRP2, you need to put the txrx_wbx.bin on the SD card,
which you can obtain by building the firmware from a recent git master
or by downloading from here:

http://gnuradio.org/releases/usrp2-bin/trunk/txrx_wbx.bin

Directions for updating your SD card can be found here:
http://gnuradio.org/redmine/wiki/gnuradio/USRP2UserFAQ#How-do-I-change-the-firmware-and-FPGA-code-on-the-SD-Card

Jason

Hello Jason and Josh,

Thanks a lot for your quick reply.

You are right. I put the file “txrx_wbx.bin” on the SD card. Now
everything
looks normal.
Thanks.

-Evan