RF Noise during connection to NRF54L15 from windows?

[Dairlab]

Dear All,

In our company, we have replaced the NRF52811 (ublox module) with NRF54L15 (raytac module) for new batches of products.

The fw is a simple BLE to UART bridge with Zephyr.

We noticed something curious: when connecting to it, we often (I would say on average 3 times out of 10) receive the error "bt_conn: con 0x20001330 failed to establish. RF noise?"

We had thought it could be a problem related to the fw, but:

- trying to connect from mobile, either IOS or Android, it never happens

- trying from Mac, it never happens

but from different windows systems (10 and 11) the problem is reproducible, quite easily (Using a simple connection with LE Explorer or Web Bluetooth from Chrome).

In order to try excluding a problem specific to our fw, we used the sample peripheral_hr available in zephyr and we observed the same behaviour as described above.

In order to avoid a problem specific to our board, we used our fw on the NRF54L15DK eval board with the same symptoms.

Has anyone faced such issues?

Best,

Dairlab

[Simonr]

Hi

What laptop(s) or desktop(s) are you using for testing here exactly? Can you confirm you've tested on more than one specific laptop when reproducing this issue? I don't see a specific reason you should see connection issues with Windows, unless the BLE antenna design on the Windows devices isn't the best. Also, at what range and in what kind of environment are you testing here? Do you see the same range working fine when using Android, iOS or Mac to connect? 

Best regards,

Simon

[Dairlab]

Yes, before posting we tried different PCs and few mobiles. Regarding the range, less than 1 meter in all cases.