# Problems of GPSDO with GPS antenna

**URL:** <https://www.ruby-forum.com/t/problems-of-gpsdo-with-gps-antenna/218489>\
**Category:** GNU Radio\
**Created:** [April 2, 2012, 2:38pm UTC](https://www.ruby-forum.com/t/problems-of-gpsdo-with-gps-antenna/218489 "2012-04-02T14:38:53Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![luislavena](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/l/0ea827/32.png) [@luislavena](https://www.ruby-forum.com/u/luislavena)\
**Post date:** [April 2, 2012, 2:38pm UTC](https://www.ruby-forum.com/t/problems-of-gpsdo-with-gps-antenna/218489/1 "2012-04-02T14:38:53Z")

</div>

Hi,

I want to use GPSDO in my application. Since there is no GPS antenna  
with  
GPSDO-kit, I bought a ‘SMA male straight GPS antenna’. Everything went  
well  
before I connect the GPS antenna to the GPSDO. For example, I can  
receive  
GPS time using usrp-\>get\_mboard\_sensor(“gps\_time”). Other uhd  
applications  
also work well.

To lock to the satellite and update the GPS time, I connected the GPS  
antenna to GPSDO. However, I got some weird errors. I even got the same  
errors when I run ‘uhd\_usrp\_probe’.

~$ uhd\_usrp\_probe  
linux; GNU C++ version 4.4.5; Boost\_104200; UHD\_003.003.000-d5d448e

– Opening a USRP2/N-Series device…  
– Current recv frame size: 1472 bytes  
– Current send frame size: 1472 bytes  
– Found a Jackson Labs GPS  
…  
UHD Warning:  
get\_time: bad lexical cast: source type value could not be  
interpreted  
as target

UHD Warning:  
get\_time: bad lexical cast: source type value could not be  
interpreted  
as target

UHD Warning:  
get\_time: bad lexical cast: source type value could not be  
interpreted  
as target

Error: ValueError: Timeout after no valid message found

Does anyone know how to fix it? I am using GPSDO+USRPN210+WBX on  
Ubuntu  
10.04.

Thanks in advance.

Regards,

Jamie

---

<div class="post-metadata">

**Author:** ![SSS\_SSS\_SS\_SS\_SSS](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/8797f3/32.png) [@SSS\_SSS\_SS\_SS\_SSS](https://www.ruby-forum.com/u/SSS_SSS_SS_SS_SSS)\
**Post date:** [April 2, 2012, 4:06pm UTC](https://www.ruby-forum.com/t/problems-of-gpsdo-with-gps-antenna/218489/2 "2012-04-02T16:06:04Z")

</div>

Update to the latest version of UHD and corresponding firmware.

On Mon, 2 Apr 2012 22:37:40 +1000, 魏俊明 wrote:

> Hi,
> 
> I want to  
> use GPSDO in my application. Since there is no GPS antenna with  
> GPSDO-kit, I bought a ‘SMA male straight GPS antenna’. Everything went  
> well before I connect the GPS antenna to the GPSDO. For example, I can  
> receive GPS time using usrp-\>get\_mboard\_sensor(“gps\_time”). Other uhd  
> applications also work well.
> 
> To lock to the satellite and update  
> the GPS time, I connected the GPS antenna to GPSDO. However, I got some  
> weird errors. I even got the same errors when I run ‘uhd\_usrp\_probe’.

> ~$ uhd\_usrp\_probe  
> linux; GNU C++ version 4.4.5; Boost\_104200;  
> UHD\_003.003.000-d5d448e
> 
> – Opening a USRP2/N-Series device…

– Current recv frame size: 1472 bytes

> – Current send frame size:  
> 1472 bytes  
> – Found a Jackson Labs GPS  
> ..  
> UHD Warning:

get\_time: bad lexical cast: source type value could not be interpreted  
as target

> UHD Warning:  
> get\_time: bad lexical cast: source type  
> value could not be interpreted as target
> 
> UHD Warning:  
> get\_time:  
> bad lexical cast: source type value could not be interpreted as target

> Error: ValueError: Timeout after no valid message found
> 
> Does  
> anyone know how to fix it? I am using GPSDO+USRPN210+WBX on Ubuntu  
> 10.04.