B1 EARFCN 300 invisible to EG12-EA

My modem Quectel EG12-EA seems to be unable to connect to B1 EARFCN 300 with italian LTE operator TIM.
Other B1 EARFCNs are ok (525 Vodafone Italia, 150 Wind3, for example).

Firmware EG12EAPAR01A10M4G.

Other modems (different vendors but same BTS, SIM and operator) connect with B1 EARFCN 300 without any issue.

Any hints?

Thank you

Is it ever showing up in the



AT+QENG="neighbourcell" with Vodafone IT (B1 EARFCN 525):

  output: +QENG: "neighbourcell intra","LTE",525,183,-13,-111,-79,0,-,-,-,-,- +QENG: "neighbourcell intra","LTE",525,15,-20,-121,-89,0,-,-,-,-,- +QENG: "neighbourcell intra","LTE",525,468,-20,-120,
          -89,0,-,-,-,-,- +QENG: "neighbourcell intra","LTE",525,39,-20,-118,-90,0,-,-,-,-,- +QENG: "neighbourcell inter","LTE",1850,199,-15,-113,-90,0,-,-,-,- +QENG: "neighbourcell inter","LTE",1850,
          238,-19,-116,-89,0,-,-,-,- +QENG: "neighbourcell inter","LTE",1850,430,-18,-117,-89,0,-,-,-,- +QENG: "neighbourcell inter","LTE",1850,474,-20,-119,-89,0,-,-,-,- +QENG: "neighbourcell inter",
          "LTE",1850,36,-20,-119,-88,0,-,-,-,- +QENG: "neighbourcell inter","LTE",1850,37,-20,-119,-88,0,-,-,-,- +QENG: "neighbourcell inter","LTE",1850,339,-20,-118,-88,0,-,-,-,- +QENG: 
          "neighbourcell inter","LTE",1850,364,-20,-119,-90,0,-,-,-,- +QENG: "neighbourcell inter","LTE",3025,64,-8,-117,-100,0,-,-,-,- OK

so B1 functionality seems to be ok (EARFCN 525 in this case, but works also for EARFCN 150).

AT+QENG="neighbourcell" with TIM IT (no B1 EARFCN 300 shown, only B3 and B20, verified by other modems):

output: +QENG: "neighbourcell intra","LTE",1350,497,-15,-117,-78,0,-,-,-,-,- +QENG: "neighbourcell intra","LTE",1350,20,-19,-119,-89,0,-,-,-,-,- +QENG: "neighbourcell intra","LTE",1350,254,-20,-121,
          -89,0,-,-,-,-,- +QENG: "neighbourcell intra","LTE",1350,342,-20,-121,-88,0,-,-,-,-,- +QENG: "neighbourcell intra","LTE",1350,4,-20,-121,-88,0,-,-,-,-,- +QENG: "neighbourcell inter","LTE",
          6300,202,-15,-106,-84,0,-,-,-,- +QENG: "neighbourcell inter","LTE",6300,132,-20,-111,-82,0,-,-,-,- +QENG: "neighbourcell inter","LTE",6300,484,-20,-113,-83,0,-,-,-,- +QENG: "neighbourcell 
          inter","LTE",6300,1,-18,-114,-83,0,-,-,-,- +QENG: "neighbourcell inter","LTE",6300,374,-16,-106,-82,0,-,-,-,- +QENG: "neighbourcell inter","LTE",6300,459,-18,-111,-82,0,-,-,-,- OK

If I try to lock only B1, in general, there’s no connection at all with EG12-EA and the result of AT+QENG="neighbourcell" is only:
output: OK

B1 cell-ID 242 and 240 received by another modem (R11e-LTE6 Mikrotik), same BTS, SIM and operator:
so B1 EARFCN 300 (PHY Cell ID 242) exist ad it is operational for that BTS.

It seems very unlikely your antenna is blind to that specific frequency.

It will be interesting to see what sense a Quectel engineer makes of it.

Test #2… in front of a TIM BTS with B1+B3+B20 (B1 invisible for EG12-EA)

  output: +QENG: "neighbourcell intra","LTE",1350,102,-9,-91,-62,0,-,-,-,-,- +QENG: "neighbourcell intra","LTE",1350,104,-19,-102,-74,0,-,-,-,-,- +QENG: "neighbourcell intra","LTE",1350,495,
          -20,-99,-71,0,-,-,-,-,- +QENG: "neighbourcell intra","LTE",1350,497,-20,-103,-71,0,-,-,-,-,- +QENG: "neighbourcell inter","LTE",6300,94,-12,-83,-61,0,-,-,-,- +QENG: "neighbourcell 
          inter","LTE",6300,95,-18,-90,-61,0,-,-,-,- +QENG: "neighbourcell inter","LTE",6300,201,-20,-93,-61,0,-,-,-,- +QENG: "neighbourcell inter","LTE",6300,202,-20,-93,-61,0,-,-,-,- OK

  output: +QENG: "servingcell","NOCONN","LTE","FDD",222,01,4975104,102,1350,3,5,5,C2E,-92,-8,-64,14,-,-,-