# Using USRP and Osmo sources

**URL:** <https://www.ruby-forum.com/t/using-usrp-and-osmo-sources/234560>\
**Category:** GNU Radio\
**Created:** [March 13, 2015, 3:21pm UTC](https://www.ruby-forum.com/t/using-usrp-and-osmo-sources/234560 "2015-03-13T15:21:57Z")\
**Posts on this page:** 3\
**Page:** 1

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**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:** [March 13, 2015, 3:21pm UTC](https://www.ruby-forum.com/t/using-usrp-and-osmo-sources/234560/1 "2015-03-13T15:21:57Z")

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Has anyone used a USRP and Osmosdr source together on the same graph? I  
am trying. To run a HackRF and an Ettus b200 together and I am getting a  
lot of 'D’s. I have tried putting both at a low sampling rate but it  
doesn’t seem to change things. I am running it on an i7 so there should  
be enough CPU. Could it be a USB issue? Could the drivers be  
interfering?

Sent from my iPhone

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**Author:** ![hagus](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/9de053/32.png) [@hagus](https://www.ruby-forum.com/u/hagus)\
**Post date:** [March 13, 2015, 4:12pm UTC](https://www.ruby-forum.com/t/using-usrp-and-osmo-sources/234560/2 "2015-03-13T16:12:41Z")

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You might try running your USRP and HackRF on separate USB controllers.  
Different ports on the same controller, _might_ be leading to conflicts  
in packet scheduling at a fairly-low layer in the stack. I think HackRF  
uses libusb, just like USRPs, so they are subject to the same  
constraints in underlying USB drivers.

On 2015-03-13 10:08, Luke B. wrote:

> Has anyone used a USRP and Osmosdr source together on the same graph? I am  
> trying. To run a HackRF and an Ettus b200 together and I am getting a lot of 'D’s.  
> I have tried putting both at a low sampling rate but it doesn’t seem to change  
> things. I am running it on an i7 so there should be enough CPU. Could it be a USB  
> issue? Could the drivers be interfering?
> 
> Sent from my iPhone
> 
> * * *
> 
> 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) [1]

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<div class="post-metadata">

**Author:** ![hagus](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/9de053/32.png) [@hagus](https://www.ruby-forum.com/u/hagus)\
**Post date:** [March 13, 2015, 4:20pm UTC](https://www.ruby-forum.com/t/using-usrp-and-osmo-sources/234560/3 "2015-03-13T16:20:16Z")

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Maybe you’re seeing a classical two-clock problem: The USRP’s and the  
the HackRF’s have independent oscillators, and so the sampling rates are  
not really exactly related to each other – for example, your USRP could  
be asked to sample 10MS/s, giving you 10.000003MS/s, whereas the HackRF  
is configured to transmit 10MS/s, and consumes 9.999990MS/s. After a few  
seconds, samples start piling up.