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If my LTE uplink channel is right on the band 20 edge for example 861.9MHz or 24449 EARFCN and my LTE BW is 10MHz does that mean the final signal would be outside of B20 or 856.9-866.9 ?

Or is the final BB signal shifted toward the middle of the band, 852-862?

The reason I ask is because I have an ISM radio operating at 868MHz and I'm worred that the LTE modem will interfere when it's at the edge of B20.

Engo
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    Occupied bandwith and out of band emissions are tested when you do radio compliance tests (ETSI standards). If you have reason to believe the device is compliant, then it shouldn't interfere. If you are using 868MHz you should mainly be worrying about 1) other devices transmitting at 868MHz and 2) harmonics of devices transmitting at 434MHz - there's a reason that 868MHz is a license-free band and that reason is the 434MHz band. – Lundin Nov 02 '21 at 14:44
  • Ok thanks for the info, so you think if I am using the final channel or B20 that the signal does still not go outside 862MHz? How does the device then still get LTE10 or LTE20 BW and stay within the band – Engo Nov 02 '21 at 14:52
  • I know very little of LTE - but speaking of radio in general, when they test it, they may not place the carrier signal ("operating channel") so close to the end of the band that it spills energy out of the band. This is well-defined (at least in EU) by ETSI 300 220 (free standard), see the figure in 5.8. Though any radio may give spurious emissions below -36 dBm and still be compliant. But again, worry about the devices that purposely send out 25mW on 868MHz and do so perfectly legally and in compliance with ETSI. – Lundin Nov 02 '21 at 15:03

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