# Uhd newbee problem with B200+TCXO

**URL:** <https://www.ruby-forum.com/t/uhd-newbee-problem-with-b200-tcxo/233593>\
**Category:** GNU Radio\
**Created:** [December 27, 2014, 2:54pm UTC](https://www.ruby-forum.com/t/uhd-newbee-problem-with-b200-tcxo/233593 "2014-12-27T14:54:41Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![addis\_a](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c4cdca/32.png) [@addis\_a](https://www.ruby-forum.com/u/addis_a)\
**Post date:** [December 27, 2014, 2:54pm UTC](https://www.ruby-forum.com/t/uhd-newbee-problem-with-b200-tcxo/233593/1 "2014-12-27T14:54:41Z")

</div>

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](http://ettus.com) website that a GPS antenna wasn’t required for the TXCO.

Any help much appreciated.

---

<div class="post-metadata">

**Author:** ![Thomas\_Early](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/e5b9ba/32.png) [@Thomas\_Early](https://www.ruby-forum.com/u/Thomas_Early)\
**Post date:** [December 27, 2014, 5:59pm UTC](https://www.ruby-forum.com/t/uhd-newbee-problem-with-b200-tcxo/233593/2 "2014-12-27T17:59:38Z")

</div>

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.
> 
> * * *
> 
> Discuss-gnuradio mailing list  
> [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
> [Discuss-gnuradio Info Page](https://lists.gnu.org/mailman/listinfo/discuss-gnuradio)

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

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