# Transmit time tagging with GNU radio

**URL:** <https://discourse.myriadrf.org/t/transmit-time-tagging-with-gnu-radio/2284>\
**Category:** General Discussion\
**Created:** [23 January 2018 12:27 UTC](https://discourse.myriadrf.org/t/transmit-time-tagging-with-gnu-radio/2284 "2018-01-23T12:27:07Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![adim](https://avatars.discourse-cdn.com/v4/letter/a/8edcca/32.png) [@adim](https://discourse.myriadrf.org/u/adim)\
**Post date:** [23 January 2018 12:27 UTC](https://discourse.myriadrf.org/t/transmit-time-tagging-with-gnu-radio/2284/1 "2018-01-23T12:27:07Z")

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Hi,

Sorry if this question was answered elsewhere but: does the Lime SoapySDR/Osmocom API support transmit burst time tagging UHD-style?  
So basically for TDMA I want to tag a stream of samples to specify the exact time it should be transmitted. I already do this in GNU radio for the USRP.

Thanks,  
Adrian

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**Author:** ![caipiblack](https://yyz2.discourse-cdn.com/flex034/user_avatar/discourse.myriadrf.org/caipiblack/32/1886_2.png) [@caipiblack](https://discourse.myriadrf.org/u/caipiblack)\
**Post date:** [10 May 2020 15:34 UTC](https://discourse.myriadrf.org/t/transmit-time-tagging-with-gnu-radio/2284/2 "2020-05-10T15:34:23Z")

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Hi

I’m looking for the same thing,

Did you find a solution ?

Thanks

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**Author:** ![andrewback](https://avatars.discourse-cdn.com/v4/letter/a/22d042/32.png) [@andrewback](https://discourse.myriadrf.org/u/andrewback)\
**Post date:** [17 May 2020 10:34 UTC](https://discourse.myriadrf.org/t/transmit-time-tagging-with-gnu-radio/2284/3 "2020-05-17T10:34:39Z")

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Not sure if this is what you mean:

> [@How to transmit bursts with Soapy SDR](https://discourse.myriadrf.org/t/how-to-transmit-bursts-with-soapy-sdr/3516/3):
>
> Thanks Josh Here is what I found empirically to answer my questions. This may help others as there doesn’t seem to be any thorough code example to send and receive: You can send the entire buffer straight, but it seems smaller buffer get transmitted faster (eg a 275000 samples buffer seems to start being transmitted around 200µs later than a 10 times smaller buffer) The transmission indeed stops once the whole buffer is sent (there used to be a bug in a previous version that required you …

[http://pothosware.github.io/SoapySDR/doxygen/0.7.1/classSoapySDR\_1\_1Device.html#aff08c2bfc323cd8d6d56b5f5d4432a97](http://pothosware.github.io/SoapySDR/doxygen/0.7.1/classSoapySDR_1_1Device.html#aff08c2bfc323cd8d6d56b5f5d4432a97)

[http://pothosware.github.io/SoapySDR/doxygen/0.7.1/Constants\_8h.html#a67027b65f63dffe851594c2df4a9d034](http://pothosware.github.io/SoapySDR/doxygen/0.7.1/Constants_8h.html#a67027b65f63dffe851594c2df4a9d034)

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<div class="post-metadata">

**Author:** ![adim](https://avatars.discourse-cdn.com/v4/letter/a/8edcca/32.png) [@adim](https://discourse.myriadrf.org/u/adim)\
**Post date:** [17 May 2020 15:13 UTC](https://discourse.myriadrf.org/t/transmit-time-tagging-with-gnu-radio/2284/4 "2020-05-17T15:13:47Z")

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gr-osmosdr doesn’t have support for tagging burst with the time, however gr-limesdr does have tx\_time tags. Didn’t get to play with this feature yet, however since osmo-trx does it, I assume gr-limesdr does not necessarily need to be used directly.

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**Author:** ![andrewback](https://avatars.discourse-cdn.com/v4/letter/a/22d042/32.png) [@andrewback](https://discourse.myriadrf.org/u/andrewback)\
**Post date:** [17 May 2020 19:56 UTC](https://discourse.myriadrf.org/t/transmit-time-tagging-with-gnu-radio/2284/5 "2020-05-17T19:56:52Z")

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It’s in LMS API, which SoapySDR and gr-limesdr both sit on top of.