# 2 problems about LimeSDR

**URL:** <https://discourse.myriadrf.org/t/2-problems-about-limesdr/1531>\
**Category:** LimeSDR\
**Created:** [29 July 2017 02:42 UTC](https://discourse.myriadrf.org/t/2-problems-about-limesdr/1531 "2017-07-29T02:42:27Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![shao](https://avatars.discourse-cdn.com/v4/letter/s/aeb1de/32.png) [@shao](https://discourse.myriadrf.org/u/shao)\
**Post date:** [29 July 2017 02:42 UTC](https://discourse.myriadrf.org/t/2-problems-about-limesdr/1531/1 "2017-07-29T02:42:27Z")

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I ordered dozens of LimeSDRs. I have now find problems of 2 boards.

1.One of my board’s LED is not lighten at all when I plug into my computer.  
LimeUtil --find / SoapySDRUtil --find shows nothing.  
Sometimes my computers says this USB device draws too much current. But the same computer supports other LimeSDR.

 ![](https://canada1.discourse-cdn.com/flex034/uploads/myriadrf/original/2X/d/d55f12d35c5f083c7ca50daf3e305e37f7081e7c.JPG)

2.Another problem is, when I am transmitting a constant signal. The amplitude shown in oscilloscope is always changing, this causes error codes, when transmitting digital data. We have B210 in comparison, the amplitude doesn’t vary that much. I think this might not be a single board problem, since the other LimeSDR shows similar results. If there is some way we need to configure, please advise.

I am told that I am not allowed to upload videos, so I uploaded 2 screen shots which also shows the amplitude is changing

 ![](https://canada1.discourse-cdn.com/flex034/uploads/myriadrf/original/2X/4/438086db0bf3b299b98856b59e5356d9ac4dd950.jpeg)

This is when LimeSDR is transmitting, you can see the amplitude is not stable.

 ![](https://canada1.discourse-cdn.com/flex034/uploads/myriadrf/original/2X/5/5f94b572943aed3022f18aa900b135b8ce253a13.jpeg)

This is when B210 is transmitting, its amplitude doesn’t vary much.

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**Author:** ![Kc7noa](https://yyz2.discourse-cdn.com/flex034/user_avatar/discourse.myriadrf.org/kc7noa/32/144_2.png) [@Kc7noa](https://discourse.myriadrf.org/u/Kc7noa)\
**Post date:** [31 July 2017 01:30 UTC](https://discourse.myriadrf.org/t/2-problems-about-limesdr/1531/2 "2017-07-31T01:30:03Z")

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Upload video to youtube and paste the short link

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**Author:** ![shao](https://avatars.discourse-cdn.com/v4/letter/s/aeb1de/32.png) [@shao](https://discourse.myriadrf.org/u/shao)\
**Post date:** [31 July 2017 03:36 UTC](https://discourse.myriadrf.org/t/2-problems-about-limesdr/1531/3 "2017-07-31T03:36:35Z")

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Please take a look, thank you.

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**Author:** ![mzs](https://yyz2.discourse-cdn.com/flex034/user_avatar/discourse.myriadrf.org/mzs/32/2678_2.png) [@mzs](https://discourse.myriadrf.org/u/mzs)\
**Post date:** [31 July 2017 10:03 UTC](https://discourse.myriadrf.org/t/2-problems-about-limesdr/1531/4 "2017-07-31T10:03:26Z")

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You are transmitting a Continuous wave at 500 MHz, I’m curious [what sample rate were you using](https://discourse.myriadrf.org/t/limesdr-transmits-noise-or-maybe-harmonics-at-low-sample-rates/1468/2?u=mzs) for TX ?

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**Author:** ![shao](https://avatars.discourse-cdn.com/v4/letter/s/aeb1de/32.png) [@shao](https://discourse.myriadrf.org/u/shao)\
**Post date:** [31 July 2017 10:20 UTC](https://discourse.myriadrf.org/t/2-problems-about-limesdr/1531/5 "2017-07-31T10:20:34Z")

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The carrier frequency is around 240MHz, I used it to transmit a constant wave. The transmitting sample rate is 10MHz.