Help getting started

Hi all,

I’m just beginning grad school and trying to get my USRP board up and
running so I can start playing. I’ve tested our equipment on two
different machines now; one an older box running FC4, 512MB ram, with an
Intel(R) Celeron(R) CPU 2.40GHz. I’ve also tried one on a newer laptop
(compaq v3000 series) running Gentoo Linux, with 2GB of memory. I’ve had
/all kinds/ of interesting phenomena:

I first tried installing the way on the old wiki
http://www.comsec.com/wiki?UniversalSoftwareRadioPeripheral (first link
on Google for USRP), and then again using the new say (svn source
checkout using the instructions on the new wiki), on both machines. On
the older machine, I don’t get any rx/tx over/underruns (or maybe just
one when initializing) and a throughput of 32MB/s in both directions,
and on the laptop I get exactly 41 under/over runs with a throughput of
~31MB/s in the RX direction and around 24 in the TX direction. As far as
I could tell, these used the same version of the source, but then again
the SVN repository has jumped from rev. 3772 to rev. 3785 since
yesterday morning.

Anyway, installation, make check, and the ./test_standard_?x scripts
work fine (the LED behaves as expected and the benchmarks seem
reasonable), however I get nothing when running the usrp_oscope or
usrp_wfm_rcv scripts as directed in the instructions. Both dial tone
scripts work fine, by the way. The scope and FM receive scripts run
fine, but I hear just hear/see static. If I set the oscope to 900MHz and
bring my cordless 900MHz phone around, there’s no change in the scope.
If I can the entire FM spectrum in the other script, I don’t get
anything but static anywhere. My little portable CD player can hear the
radio just fine in this lab, so I figure the foot-long copper antenna
that came with the USRP ought to as well. I don’t know a lot about
communications…

Also, the different test_digital_loopback and test_counting scripts seem
to not work very well at all. I don’t know if they’re expected to, but
about 50% of the tests that look vaguely “expected 517, got 0” fail.

Is there any advice you can offer as to how to determine what, if
anything, is wrong here?

Thanks,

Dan

Hi Dan,

What daughterboards are you using?

Thanks,

Written

Dan H. wrote:

I first tried installing the way on the old wiki

that came with the USRP ought to as well. I don’t know a lot about


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I’ve used the 2.4GHz RX/TX board, but I have since been using the Basic
RX and Basic TX boards.

-Dan

Fair enough; I figured since my officemate’s pocket CD player could pick
up FM radio the big ole’ antenna ought to be able to.

Is there a script to make a custom FM station using a BasicTX board (I
have another USRP if necessary) to get around that problem?

-Dan

Well, all I can think of is using the basic rx daugtherboard along with
usrp_wfm_rcv.py and tuning to some local FM stations, or using the
scope,
but it sounds like you’ve already done that pretty much. Make sure the
gain
on the scope is set to about mid-point for the specific daughterboard
being
used. I had the best luck with this.

Depending on your scanning bandwidth, I don’t know if you’ll actually
pick
up any listenable stations, so I’d just use the aforementioned file for
FM
testing purposes.

Written

Dan H. wrote:

running so I can start playing. I’ve tested our equipment on two
one when initializing) and a throughput of 32MB/s in both directions,
scripts work fine, by the way. The scope and FM receive scripts run
to not work very well at all. I don’t know if they’re expected to, but


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Well, I’ve never used the TX boards before, but looking through the
files I
found fm_tx.py, which makes narrow band fm. You may have to use
usrp_nbfm_rcv.py (or whatever it’s called) to pick it up, but now I’m
just
guessing.

-Written

Dan H. wrote:

Well, all I can think of is using the basic rx daugtherboard along with
FM

-Dan

Intel(R) Celeron(R) CPU 2.40GHz. I’ve also tried one on a newer laptop
one when initializing) and a throughput of 32MB/s in both directions,
work fine (the LED behaves as expected and the benchmarks seem
that came with the USRP ought to as well. I don’t know a lot about
anything, is wrong here?

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