nRF9160 Not connecting over LTE on custom board

[RodWatt]

I have designed my own board, based around the nRF9160 but unfortunately I am unable to connect to an LTE network. 

I am running the at_client code and using LTE Link Monitor. Below, is the log file.

2020-02-15T15:26:18.899Z DEBUG modem >> AT\x0D\x0A
2020-02-15T15:26:18.923Z DEBUG modem << OK\x0D\x0A\x00
2020-02-15T15:26:20.627Z DEBUG modem >> AT+CFUN?\x0D\x0A
2020-02-15T15:26:20.651Z DEBUG modem << +CFUN: 0\x0D\x0A
2020-02-15T15:26:20.673Z DEBUG modem << OK\x0D\x0A\x00
2020-02-15T15:26:22.754Z DEBUG modem >> AT+CFUN=1\x0D\x0A
2020-02-15T15:26:22.811Z DEBUG modem << OK\x0D\x0A\x00
2020-02-15T15:26:23.996Z DEBUG modem >> AT+CFUN?\x0D\x0A
2020-02-15T15:26:24.011Z DEBUG modem << +CFUN: 1\x0D\x0A
2020-02-15T15:26:24.024Z DEBUG modem << OK\x0D\x0A\x00
2020-02-15T15:26:24.035Z DEBUG modem >> AT+CGSN=1\x0D\x0A
2020-02-15T15:26:24.043Z DEBUG modem << +CGSN: "352656100636847"\x0D\x0A
2020-02-15T15:26:24.045Z DEBUG modem << OK\x0D
2020-02-15T15:26:24.055Z DEBUG modem >> AT+CGMI\x0D\x0A
2020-02-15T15:26:24.074Z DEBUG modem << Nordic Semiconductor ASA\x0D\x0A
2020-02-15T15:26:24.078Z DEBUG modem << OK\x0D\x0A\x00
2020-02-15T15:26:24.082Z DEBUG modem >> AT+CGMM\x0D\x0A
2020-02-15T15:26:24.094Z DEBUG modem << nRF9160-SIBA\x0D\x0A
2020-02-15T15:26:24.096Z DEBUG modem << OK\x0D\x0A\x00
2020-02-15T15:26:24.103Z DEBUG modem >> AT+CGMR\x0D\x0A
2020-02-15T15:26:24.123Z DEBUG modem << mfw_nrf9160_1.1.1\x0D\x0A
2020-02-15T15:26:24.126Z DEBUG modem << OK\x0D\x0A\x00
2020-02-15T15:26:24.129Z INFO Nordic Semiconductor ASA nRF9160-SIBA [mfw_nrf9160_1.1.1] SerNr: 352656100636847
2020-02-15T15:26:24.130Z DEBUG modem >> AT+CEMODE?\x0D\x0A
2020-02-15T15:26:24.140Z DEBUG modem << +CEMODE: 0\x0D\x0A
2020-02-15T15:26:24.143Z DEBUG modem << OK\x0D\x0A\x00
2020-02-15T15:26:24.160Z DEBUG modem >> AT%XCBAND=?\x0D\x0A
2020-02-15T15:26:24.171Z DEBUG modem << %XCBAND: (1,2,3,4,5,8,12,13,17,19,20,25,26,28,66)\x0D\x0A
2020-02-15T15:26:24.173Z DEBUG modem << OK\x0D\x0A\x00
2020-02-15T15:26:24.189Z DEBUG modem >> AT+CMEE?\x0D\x0A
2020-02-15T15:26:24.241Z DEBUG modem << +CMEE: 0\x0D\x0A
2020-02-15T15:26:24.243Z DEBUG modem << OK\x0D\x0A\x00
2020-02-15T15:26:24.253Z DEBUG modem >> AT+CMEE=1\x0D\x0A
2020-02-15T15:26:24.270Z DEBUG modem << OK\x0D\x0A\x00
2020-02-15T15:26:24.274Z DEBUG modem >> AT+CNEC?\x0D\x0A
2020-02-15T15:26:24.287Z DEBUG modem << +CNEC: 0\x0D\x0A
2020-02-15T15:26:24.295Z DEBUG modem << OK\x0D\x0A\x00
2020-02-15T15:26:24.319Z DEBUG modem >> AT+CNEC=24\x0D\x0A
2020-02-15T15:26:24.332Z DEBUG modem << OK\x0D\x0A\x00
2020-02-15T15:26:24.337Z DEBUG modem >> AT+CGEREP?\x0D\x0A
2020-02-15T15:26:24.347Z DEBUG modem << +CGEREP: 0,0\x0D\x0A
2020-02-15T15:26:24.348Z DEBUG modem << OK\x0D\x0A\x00
2020-02-15T15:26:24.357Z DEBUG modem >> AT+CGDCONT?\x0D\x0A
2020-02-15T15:26:24.379Z DEBUG modem << OK\x0D\x0A\x00
2020-02-15T15:26:24.388Z DEBUG modem >> AT+CGACT?\x0D\x0A
2020-02-15T15:26:24.395Z DEBUG modem << OK\x0D\x0A\x00
2020-02-15T15:26:24.405Z DEBUG modem >> AT+CGEREP=1\x0D\x0A
2020-02-15T15:26:24.411Z DEBUG modem << OK\x0D\x0A\x00
2020-02-15T15:26:24.413Z DEBUG modem >> AT+CIND=1,1,1\x0D\x0A
2020-02-15T15:26:24.427Z DEBUG modem << OK\x0D\x0A\x00
2020-02-15T15:26:24.434Z DEBUG modem >> AT+CEREG=2\x0D\x0A
2020-02-15T15:26:24.448Z DEBUG modem << OK\x0D\x0A\x00
2020-02-15T15:26:24.462Z DEBUG modem >> AT+CEREG?\x0D\x0A
2020-02-15T15:26:24.475Z DEBUG modem << +CEREG: 2,4,"FFFE","FFFFFFFF",9\x0D\x0A
2020-02-15T15:26:24.477Z DEBUG modem << OK\x0D\x0A\x00
2020-02-15T15:26:24.494Z DEBUG modem >> AT%CESQ=1\x0D\x0A
2020-02-15T15:26:24.507Z DEBUG modem << OK\x0D\x0A\x00
2020-02-15T15:26:24.511Z DEBUG modem >> AT+CESQ\x0D\x0A
2020-02-15T15:26:24.524Z DEBUG modem << +CESQ: 99,99,255,255,255,255\x0D\x0A
2020-02-15T15:26:24.527Z DEBUG modem << OK\x0D\x0A\x00
2020-02-15T15:26:24.550Z DEBUG modem >> AT%XSIM=1\x0D\x0A
2020-02-15T15:26:24.571Z DEBUG modem << OK\x0D\x0A\x00
2020-02-15T15:26:24.575Z DEBUG modem >> AT%XSIM?\x0D\x0A
2020-02-15T15:26:24.587Z DEBUG modem << %XSIM: 1\x0D\x0A
2020-02-15T15:26:24.590Z DEBUG modem << OK\x0D\x0A\x00
2020-02-15T15:26:24.605Z DEBUG modem >> AT+CPIN?\x0D\x0A
2020-02-15T15:26:24.621Z DEBUG modem << +CPIN: READY\x0D\x0A
2020-02-15T15:26:24.624Z DEBUG modem << OK\x0D\x0A\x00
2020-02-15T15:26:24.648Z DEBUG modem >> AT+CPINR="SIM PIN"\x0D\x0A
2020-02-15T15:26:24.683Z DEBUG modem << +CPINR: "SIM PIN",3\x0D\x0A
2020-02-15T15:26:24.686Z DEBUG modem << OK\x0D\x0A\x00
2020-02-15T15:26:24.693Z DEBUG modem >> AT+CIMI\x0D\x0A
2020-02-15T15:26:24.705Z DEBUG modem << 204080813513474\x0D\x0A
2020-02-15T15:26:24.707Z DEBUG modem << OK\x0D\x0A\x00
2020-02-15T15:26:24.709Z INFO IMSIdentity: 204080813513474
2020-02-15T15:26:32.419Z DEBUG modem >> AT+COPS=?\x0D\x0A
2020-02-15T15:27:32.425Z ERROR Network search failed: Error: 'AT+COPS=?
' timed out

I have used the same SIM in the nRF9160DK and I do get a connection, all be it very weak. I am only seeing 1 bar in the LTE

Link Monitor application. 

The obvious difference is the layout of the two boards, however, I had the layout and schematics checked and "Ok'ed" by someone at Nordic so am quietly confident its OK.

Th other concern is the fact the signal is very weak.

I would appreciate any thought son how to move forward.

Thanks,

Rod

[Kaja]

Hi Rod, 

it might be that the antenna is too close to the ground to the right, but the antenna datasheet does not specify anything in this regard so it is hard to say. Have you had the antenna manufacturer look through the design as well? 

You might just need to tune the components values on the matching network. 

Best regards,
Kaja

[RodWatt]

Hi Kaja,

Ok, a bit more investigating and it looks like my board has the NBIOT only part fitted. I have an nRF9160-SIBA fitted. (I see the nRF9160DK has the - SICA fitted) So, am I correct in saying that my board will only support NB-IOT? (and not LTE?)

Can I still use the LTE Link Monitor to connected to NB-IOT?

What changes do I need to make to the AT commands?

Thanks,

Rod