# Loopback TX\_1 -\> LNA\_W failed

**URL:** <https://discourse.myriadrf.org/t/loopback-tx-1-lna-w-failed/3927>\
**Category:** LimeSDR\
**Created:** [29 December 2018 09:48 UTC](https://discourse.myriadrf.org/t/loopback-tx-1-lna-w-failed/3927 "2018-12-29T09:48:28Z")\
**Posts on this page:** 13\
**Page:** 1

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**Author:** ![pe2ben](https://avatars.discourse-cdn.com/v4/letter/p/c4cdca/32.png) [@pe2ben](https://discourse.myriadrf.org/u/pe2ben)\
**Post date:** [29 December 2018 09:48 UTC](https://discourse.myriadrf.org/t/loopback-tx-1-lna-w-failed/3927/1 "2018-12-29T09:48:28Z")

</div>

Hello,

The LimeQuickTest TX\_1 -\> LNA\_W give me the following results:  
[RF Loopback Test]  
-\>Configure LMS  
-\>Run Tests (TX\_2-\> LNA\_L):  
CH0 (SXR=800.0MHz, SXT=805.0MHz): Result:(-15.4 dBFS, 5.00 MHz) - PASSED  
CH1 (SXR=800.0MHz, SXT=805.0MHz): Result:(-17.6 dBFS, 5.00 MHz) - PASSED  
-\>Run Tests (TX\_1 -\> LNA\_W):  
CH0 (SXR=1800.0MHz, SXT=1805.0MHz): Result:(-19.8 dBFS, 5.00 MHz) - PASSED  
CH1 (SXR=1800.0MHz, SXT=1805.0MHz): Result:(-22.7 dBFS, 5.00 MHz) - FAILED  
-\>Run Tests (TX\_2-\> LNA\_H):  
CH0 (SXR=2500.0MHz, SXT=2505.0MHz): Result:(-17.4 dBFS, 5.00 MHz) - PASSED  
CH1 (SXR=2500.0MHz, SXT=2505.0MHz): Result:(-16.4 dBFS, 5.00 MHz) - PASSED  
-\>RF Loopback Test FAILED

=\> Board tests FAILED \<=

Is this a serious Problem? I can’t see any damage.

Regards Ben

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<div class="post-metadata">

**Author:** ![pe2ben](https://avatars.discourse-cdn.com/v4/letter/p/c4cdca/32.png) [@pe2ben](https://discourse.myriadrf.org/u/pe2ben)\
**Post date:** [2 January 2019 22:38 UTC](https://discourse.myriadrf.org/t/loopback-tx-1-lna-w-failed/3927/2 "2019-01-02T22:38:09Z")

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Hello everyone,  
Could this fault caused by the HF mod done by Lime (LN54 - RX2\_W)?  
Do I have send it back or is this normal (-22.7 dBFS) after that mod?  
Regards Ben

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**Author:** ![zeewox](https://avatars.discourse-cdn.com/v4/letter/z/a5b964/32.png) [@zeewox](https://discourse.myriadrf.org/u/zeewox)\
**Post date:** [5 January 2019 12:52 UTC](https://discourse.myriadrf.org/t/loopback-tx-1-lna-w-failed/3927/3 "2019-01-05T12:52:01Z")

</div>

Hello,

I have the exact same issue.

I noticed however that all tests pass when i disconnect the antenna from TX1\_1.  
Can you reproduce ?

Anyone could confirm that limesdr-usb is supposed to pass all tests from LimeQuickTest ?

Thank you  
Regards,  
Fred

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<div class="post-metadata">

**Author:** ![pe2ben](https://avatars.discourse-cdn.com/v4/letter/p/c4cdca/32.png) [@pe2ben](https://discourse.myriadrf.org/u/pe2ben)\
**Post date:** [6 January 2019 10:01 UTC](https://discourse.myriadrf.org/t/loopback-tx-1-lna-w-failed/3927/4 "2019-01-06T10:01:19Z")

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Hello Fred,  
The first time without a antenna all the tests passed.  
But after I connect the antenna again the loopback test failed.  
After this test I disconnect the antenna and I would expect that all the tests would be passed now but that was not the case.  
It doesn’t matter on witch port the antenna is. No change.  
So after one time passed without antenna connected the fault situation is the same again.  
Strange problem…  
Regard Ben

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<div class="post-metadata">

**Author:** ![pe2ben](https://avatars.discourse-cdn.com/v4/letter/p/c4cdca/32.png) [@pe2ben](https://discourse.myriadrf.org/u/pe2ben)\
**Post date:** [6 January 2019 12:25 UTC](https://discourse.myriadrf.org/t/loopback-tx-1-lna-w-failed/3927/5 "2019-01-06T12:25:28Z")

</div>

Update:  
It looks like the problem start a short time (1 a 2 minutes) after a the limeSDR is connected.  
Only just after startup there is no problem.  
Maybe temperature related ?

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<div class="post-metadata">

**Author:** ![zeewox](https://avatars.discourse-cdn.com/v4/letter/z/a5b964/32.png) [@zeewox](https://discourse.myriadrf.org/u/zeewox)\
**Post date:** [22 January 2019 06:36 UTC](https://discourse.myriadrf.org/t/loopback-tx-1-lna-w-failed/3927/6 "2019-01-22T06:36:05Z")

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@pe2ben mine fails even on cold boot.

@andrewback hello, could you please advise ? We seem to have a hardware issue since the basic QuickTest fails.

Thank you  
Regards  
Fred

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<div class="post-metadata">

**Author:** ![andrewback](https://avatars.discourse-cdn.com/v4/letter/a/22d042/32.png) [@andrewback](https://discourse.myriadrf.org/u/andrewback)\
**Post date:** [22 January 2019 08:39 UTC](https://discourse.myriadrf.org/t/loopback-tx-1-lna-w-failed/3927/7 "2019-01-22T08:39:05Z")

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@zeewox, sure, we will need @zack to make sure that we have tried everything possible and, if it really does look like a hardware problem, arrange RMA.

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<div class="post-metadata">

**Author:** ![Zack](https://yyz2.discourse-cdn.com/flex034/user_avatar/discourse.myriadrf.org/zack/32/89_2.png) [@Zack](https://discourse.myriadrf.org/u/Zack)\
**Post date:** [23 January 2019 09:24 UTC](https://discourse.myriadrf.org/t/loopback-tx-1-lna-w-failed/3927/8 "2019-01-23T09:24:56Z")

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Hi @zeewox,

Test it using [LimeQuickTest](https://wiki.myriadrf.org/LimeQuickTest) and share the result, please.

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<div class="post-metadata">

**Author:** ![pe2ben](https://avatars.discourse-cdn.com/v4/letter/p/c4cdca/32.png) [@pe2ben](https://discourse.myriadrf.org/u/pe2ben)\
**Post date:** [28 January 2019 21:38 UTC](https://discourse.myriadrf.org/t/loopback-tx-1-lna-w-failed/3927/9 "2019-01-28T21:38:05Z")

</div>

Hello Zack,  
what can you tell me regarding my output from my LimeQuickTest above?  
Regards Ben, PE2BEN

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<div class="post-metadata">

**Author:** ![zeewox](https://avatars.discourse-cdn.com/v4/letter/z/a5b964/32.png) [@zeewox](https://discourse.myriadrf.org/u/zeewox)\
**Post date:** [1 February 2019 23:49 UTC](https://discourse.myriadrf.org/t/loopback-tx-1-lna-w-failed/3927/10 "2019-02-01T23:49:42Z")

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Hello @Zack,

here’s the result from LimeQuickTest :

```
[TESTING STARTED]
->Start time: Sat Feb 2 00:13:13 2019

->Device: LimeSDR-USB, media=USB 3.0, module=FX3, addr=1d50:6108, serial=00090726XXXXXXXX
  Serial Number: 00090726XXXXXXXX

[Clock Network Test]
->FX3 GPIF clock test
  Test results: 65211; 3431; 7187 - PASSED
->Si5351C test
  CLK0: 17554 / 17554 - PASSED
  CLK1: 17554 / 17554 - PASSED
  CLK2: 17554 / 17554 - PASSED
  CLK3: 17554 / 17554 - PASSED
  CLK4: 17554 / 17554 - PASSED
  CLK5: 17554 / 17554 - PASSED
  CLK6: 17554 / 17554 - PASSED
->ADF4002 Test
  Result: 10 - PASSED
->VCTCXO test
  Results : 5112947 (min); 5113081 (max) - PASSED
->Clock Network Test PASSED

[FPGA EEPROM Test]
->Read EEPROM
->Read data: 12 07 19 12 07 19 02
->FPGA EEPROM Test PASSED

[LMS7002M Test]
->Perform Registers Test
->External Reset line test
  Reg 0x20: Write value 0xFFFD, Read value 0xFFFD
  Reg 0x20: value after reset 0x0FFFF
->LMS7002M Test PASSED

[RF Loopback Test]
->Configure LMS
->Run Tests (TX_2-> LNA_L):
  CH0 (SXR=800.0MHz, SXT=805.0MHz): Result:(-16.9 dBFS, 5.00 MHz) - PASSED
  CH1 (SXR=800.0MHz, SXT=805.0MHz): Result:(-18.1 dBFS, 5.00 MHz) - PASSED
->Run Tests (TX_1 -> LNA_W):
  CH0 (SXR=1800.0MHz, SXT=1805.0MHz): Result:(-18.3 dBFS, 5.00 MHz) - PASSED
  CH1 (SXR=1800.0MHz, SXT=1805.0MHz): Result:(-24.6 dBFS, 5.00 MHz) - FAILED
->Run Tests (TX_2-> LNA_H):
  CH0 (SXR=2500.0MHz, SXT=2505.0MHz): Result:(-17.9 dBFS, 5.00 MHz) - PASSED
  CH1 (SXR=2500.0MHz, SXT=2505.0MHz): Result:(-16.6 dBFS, 5.00 MHz) - PASSED
->RF Loopback Test FAILED

=> Board tests FAILED <=

Elapsed time: 2.54 seconds

```

I’ve tested different computers (Windows and Linux), and even tried to downgrade LimeSDR FW, but the problem persists.

Thank you for your help.

Regards.

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<div class="post-metadata">

**Author:** ![pe2ben](https://avatars.discourse-cdn.com/v4/letter/p/c4cdca/32.png) [@pe2ben](https://discourse.myriadrf.org/u/pe2ben)\
**Post date:** [5 March 2019 14:12 UTC](https://discourse.myriadrf.org/t/loopback-tx-1-lna-w-failed/3927/11 "2019-03-05T14:12:37Z")

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Hello Zack,  
Do I need RMA or is this ok?  
Regards Ben

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<div class="post-metadata">

**Author:** ![pe2ben](https://avatars.discourse-cdn.com/v4/letter/p/c4cdca/32.png) [@pe2ben](https://discourse.myriadrf.org/u/pe2ben)\
**Post date:** [8 March 2019 22:13 UTC](https://discourse.myriadrf.org/t/loopback-tx-1-lna-w-failed/3927/12 "2019-03-08T22:13:14Z")

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@andrewback or @Zack,

Please could one of you answer my question.

Regards Ben

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<div class="post-metadata">

**Author:** ![Zack](https://yyz2.discourse-cdn.com/flex034/user_avatar/discourse.myriadrf.org/zack/32/89_2.png) [@Zack](https://discourse.myriadrf.org/u/Zack)\
**Post date:** [11 March 2019 13:36 UTC](https://discourse.myriadrf.org/t/loopback-tx-1-lna-w-failed/3927/13 "2019-03-11T13:36:08Z")

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Hi @pe2ben,

TX\_1 -\> LNA\_W of CH1 is a little bit lower, but your board is fully operational.