Uhd newbee problem with B200+TCXO

GNU Radio
1

I have a new ettus B200 with TCXO (no antenna) plugged into my ZOTAC
ZBOX USB3
port running Debian 7.7. I recently built gnuradio with the
build-gnuradio
script.

I was trying to build a broadcast FM radio receiver from available
examples
and was having some problems, so I created a simple flow of UHD source
feeding
an FFT sink and I still get the sample problem. Here is my grc output:

linux; GNU C++ version 4.7.2; Boost_104900; UHD_003.008.000-52-g2068af70

<<< Welcome to GNU Radio Companion 3.7.5.1 >>>

Preferences file: /home/tom/.grc
Block paths:
/usr/local/share/gnuradio/grc/blocks
/home/tom/.grc_gnuradio

Loading: “/home/tom/grc/uhd-test.grc”

Done

Showing: “/home/tom/grc/uhd-test.grc”

Generating: “/home/tom/grc/top_block.py”

Executing: “/home/tom/grc/top_block.py”

linux; GNU C++ version 4.7.2; Boost_104900; UHD_003.008.000-52-g2068af70

Using Volk machine: avx_64_mmx_orc
– Operating over USB 3.
– Detecting internal GPSDO… Found an internal GPSDO
– Initialize CODEC control…
– Initialize Radio control…
– Performing register loopback test… pass
– Performing CODEC loopback test… pass
– Asking for clock rate 32.000000 MHz…
– Actually got clock rate 32.000000 MHz.
– Performing timer loopback test… pass
– Setting master clock rate selection to ‘automatic’.
– Setting references to the internal GPSDO
– Initializing time to the internal GPSDO

UHD Warning:
get_time: ValueError: get_nmea(): no GPRMC message found

UHD Warning:
get_time: ValueError: get_nmea(): no GPRMC message found
Traceback (most recent call last):
File “/home/tom/grc/top_block.py”, line 92, in
tb = top_block()
File “/home/tom/grc/top_block.py”, line 58, in init
channels=range(1),
File
“/usr/local/lib/python2.7/dist-packages/gnuradio/uhd/init.py”, line
122, in constructor_interceptor
return old_constructor(*args)
File
“/usr/local/lib/python2.7/dist-packages/gnuradio/uhd/uhd_swig.py”, line
1752, in make
return _uhd_swig.usrp_source_make(*args)
RuntimeError: ValueError: Timeout after no valid message found

It seems there is a lot of discussion on “no GPRMC message found” UHD
warning
that seems to point to no GPS signal, but I was under the impression
from the
ettus.com website that a GPS antenna wasn’t required for the TXCO.

Any help much appreciated.

2

On 12/27/2014 08:53 AM, Thomas Early wrote:

– Initialize Radio control…
get_time: ValueError: get_nmea(): no GPRMC message found
return old_constructor(*args)
Any help much appreciated.

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You’ve probably set the “time” and “clock” sources to “Automatic”, which
means that if there’s a GPSDO, it will use that, else it will use the
on-board
clock. Try setting those settings in the UHD source block to
explicitly use the on-board clock.

–
Marcus L.
Principal Investigator
Shirleys Bay Radio Astronomy Consortium