# Low SNIR on custom carrier board

**URL:** <https://discuss.blues.com/t/low-snir-on-custom-carrier-board/2941>\
**Category:** Uncategorized\
**Created:** [March 25, 2025, 12:54pm UTC](https://discuss.blues.com/t/low-snir-on-custom-carrier-board/2941 "2025-03-25T12:54:51Z")\
**Posts on this page:** 8\
**Page:** 1

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**Author:** ![bkauf](https://avatars.discourse-cdn.com/v4/letter/b/b4bc9f/32.png) [@bkauf](https://discuss.blues.com/u/bkauf)\
**Post date:** [March 25, 2025, 12:54pm UTC](https://discuss.blues.com/t/low-snir-on-custom-carrier-board/2941/1 "2025-03-25T12:54:51Z")

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I have a custom carrier board I made for the notecard. All seems to work well however the SINR is extremely low. Is there any other diagnostics I can check in the card to figure out what could be the problem? Below results on a WBAN with main and div antenna

{“req”:“card.wireless”,“crc”:“0003:3ce09784”}  
{‘crc’: ‘0003:68F3A61F’,  
‘net’: {‘rsrq’: -9, ‘modem’: ‘EG91NAXDGAR07A01M1G\_20.004.20.004’,  
‘internal’: True, ‘band’: ‘LTE BAND 2’, ‘imsi’: ‘310170402126508’,  
‘lac’: 2437,  
‘sinr’: 17,  
‘rssir’: -63,  
‘bars’: 3,  
‘mnc’: 410,  
‘cid’: 29905586,  
‘rssi’: -64,  
‘mcc’: 310,  
‘updated’: 1742906693,  
‘rat’: ‘lte’,  
‘iccid’: ‘89011704274021265088’,  
‘imei’: ‘868032061254805’, ‘rsrp’: -89},  
‘mode’: ‘auto’, ‘count’: 3, ‘status’: ‘{modem-off}’}

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**Author:** ![RobLauer](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.blues.com/roblauer/32/1567_2.png) [@RobLauer](https://discuss.blues.com/u/RobLauer)\
**Post date:** [March 25, 2025, 3:19pm UTC](https://discuss.blues.com/t/low-snir-on-custom-carrier-board/2941/2 "2025-03-25T15:19:49Z")

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Hi @bkauf,

A low SINR value (but high RSSI and RSRP…and high `bars`) basically means you have a strong signal that’s just not very clean. It could mean external RF noise/interference. Are you using an external (flexible) antenna or an onboard antenna on your PCB?

Rob

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**Author:** ![bkauf](https://avatars.discourse-cdn.com/v4/letter/b/b4bc9f/32.png) [@bkauf](https://discuss.blues.com/u/bkauf)\
**Post date:** [March 25, 2025, 4:19pm UTC](https://discuss.blues.com/t/low-snir-on-custom-carrier-board/2941/3 "2025-03-25T16:19:36Z")

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Hi Rob, thank you for the quick response. This is an external flexible MOLEX 2125700100 antenna [https://www.digikey.com/en/products/detail/molex/2125700100/10489644](https://www.digikey.com/en/products/detail/molex/2125700100/10489644)

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<div class="post-metadata">

**Author:** ![RobLauer](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.blues.com/roblauer/32/1567_2.png) [@RobLauer](https://discuss.blues.com/u/RobLauer)\
**Post date:** [March 25, 2025, 6:06pm UTC](https://discuss.blues.com/t/low-snir-on-custom-carrier-board/2941/4 "2025-03-25T18:06:54Z")

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Hi @bkauf,

That antenna _should_ be fine. You could try experimenting with other flexible antennas with a more broad frequency range to see if there is any difference (e.g. [the one we sell](https://shop.blues.com/collections/accessories/products/flexible-cellular-or-wi-fi-antenna) has proven quite reliable).

Rob

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<div class="post-metadata">

**Author:** ![bkauf](https://avatars.discourse-cdn.com/v4/letter/b/b4bc9f/32.png) [@bkauf](https://discuss.blues.com/u/bkauf)\
**Post date:** [March 28, 2025, 1:42am UTC](https://discuss.blues.com/t/low-snir-on-custom-carrier-board/2941/5 "2025-03-28T01:42:58Z")

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Thank you - I will test and let you know

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**Author:** ![bkauf](https://avatars.discourse-cdn.com/v4/letter/b/b4bc9f/32.png) [@bkauf](https://discuss.blues.com/u/bkauf)\
**Post date:** [April 5, 2025, 1:57pm UTC](https://discuss.blues.com/t/low-snir-on-custom-carrier-board/2941/6 "2025-04-05T13:57:47Z")

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Hi Rob,

I ran some tests today with the note carrier board and 698-4000Mhz and 698-8500Mhz Molex antennas and I can’t seem to get the SNIR up. My SNIR is very low(\<=22) in all configs. Pictures of the test setup and results which show good service(2-3 bars), rssi ~-65-61, rsrp -87-90, rsrq -9-10, but SNIR is 6-22 on a NBNA and WBNA. This testing is being done in Manhattan however I do have the some of these deployed in other areas(Kansas, North Carolina, Boston)and seeing similar results where bars are 2/3 but SNIR is extremely low(single digits)

Any ideas what’s going on or suggestions on what to try next?

 ![Screenshot 2025-04-05 at 9.56.50 AM](https://us1.discourse-cdn.com/flex020/uploads/blues/original/2X/f/f23b12803105ccf1bd4cdf45efc14415ddebdb83.jpeg)  
 ![Screenshot 2025-04-05 at 9.57.08 AM](https://us1.discourse-cdn.com/flex020/uploads/blues/original/2X/a/a68bd17095106b7e1d91b618112a5cdeb10a0df1.jpeg)  
 ![Screenshot 2025-04-05 at 9.56.59 AM](https://us1.discourse-cdn.com/flex020/uploads/blues/original/2X/6/677078b0d26ba45a38e2fe5fa0c12f7a8c299470.jpeg)

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<div class="post-metadata">

**Author:** ![RobLauer](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.blues.com/roblauer/32/1567_2.png) [@RobLauer](https://discuss.blues.com/u/RobLauer)\
**Post date:** [April 7, 2025, 4:07pm UTC](https://discuss.blues.com/t/low-snir-on-custom-carrier-board/2941/7 "2025-04-07T16:07:43Z")

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Hi @bkauf,

I just spent some time digging in to this a bit more and learned that about 3 years ago we made a change to Notecard firmware to align SINR values away from Quectel’s format (which ranged from 0-250) to a standard format of -20 to 30db (yes we need to [update our docs](https://dev.blues.io/guides-and-tutorials/notecard-guides/diagnosing-cellular-connectivity-issues/#measuring-the-quality-of-the-cellular-collection)!). This means the values you are seeing are quite good (even the 6 is “ok”). On the WBNA you could try adding a diversity antenna to the `DIV` u.fl connector to see if that improves any values.

Thanks,  
Rob

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<div class="post-metadata">

**Author:** ![bkauf](https://avatars.discourse-cdn.com/v4/letter/b/b4bc9f/32.png) [@bkauf](https://discuss.blues.com/u/bkauf)\
**Post date:** [April 8, 2025, 4:28pm UTC](https://discuss.blues.com/t/low-snir-on-custom-carrier-board/2941/8 "2025-04-08T16:28:01Z")

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Great news thanks Rob!