Does there need to be a minimum distance between Xbee 3 LTE-M/NB-IoT devices when transmitting?

Question

I have several devices (anywhere from 5-30) using Xbee 3 LTE-M/NB-IoT modems and have noticed an issue with receiving data from the units as I start to add more to the testing group. They all transmit at the same time and have good reception. I’m trying to determine if this is a cell-tower issue or something else, such as the devices interfering with each other. Has anyone run across such an issue? The devices are roughly 8 inches apart if that is helpful.

Answer 1

Yes there is a minimum distance you should keep antennas regardless of the devices. If you are not a hardware engineer, you may want to perform a google search on it or contact a hardware engineer.

Comments

Contact a hardware engineer? If I knew the hardware engineer for the Xbee 3 I would have reached out, because I don’t I’ve posted on here, sorry but that “answer” is pretty vague.

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The antennas should be at least 3 inches apart and 90 degrees from each other.

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Okay, thanks. The devices are 8 inches or more apart and the antennas for each point straight up. Perhaps the dropout of data has more to do with the amount of cellular devices connecting at the same time to the same cell tower?

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The antennas need to be 90 degrees from each other. That means one should be at 0 deg, the next should be at 90 deg.

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Hi, do you really need to do this with such low power devices? If it was several watts of rf, definitely but with 90 deg difference you will get 3bB loss to start with. I have had no problems with xbee modules next to each other. Yet I have known people blow the input devices of amateur radio equipment with as little as 3watts.