[Discuss-gnuradio] multi-antenna example

[Mark Sullivan]

Hi all,

I got my USRP up and running just fine after a fresh install of Suse
10.1 I'm working on a "walkthrough" that describes some of the problems
I encountered; I'd be happy to add it to the Wiki if anybody is
interested.

After running the USB benchmark (32M, no problem) and seeing the FFT
display work, just for fun I attached an antenna directly to my basic
RX and keyed an FRS radio nearby. No problem seeing the 465 MHz FM
signal pop up. Very cool.

Now for the only problem I've encountered. I have two basic RX cards
installed, and I'm injecting a single signal into the "RX-A" input of
the A side card at a level of about 45 dBm or so. I run the
multi-antenna capture to file code with maximum decimation (256) and
software filtering turned off for a 50 millisecond collect. I then look
at the spectrum of the resulting four files with MATLAB (sorry!). I see
my carrier in both channels 0 and 1 (but not 3 or 4) at nearly the same
level. I didn't see any error messages during the collect; is it
possible that the software couldn't keep up with the data and got out
of sync?  I'm going to try writing some test code to pull in the
data to memory before writing out to disk next. Any thoughts?

Best regards,

Mark Sullivan