I am experiencing some issues with the HL78xx modem and particular antenna configurations.
When I install the antenna inside the device’s enclosure the modem is resetting itself (LED on GPIO pin turns OFF and then ON again) after a minute or so of not being able to find a signal and that seems to happen continuously.
If the antenna is installed outside the enclosure the device operates without any issues.
I get why in the first case the modem would struggle with the signal but why is it resetting itself? Is it something known in NB-IoT ?
The network should not be able to reset a given unit. Also with regards antenna location or whether it is connected to the unit of not the unit will not be aware of this and as a result, again, will not cause a reset, all it will see is poor reception.
Are you sure the power supply is capable of handling the unit i.e. it might be trying to transmit harder with poor reception hence drawing more current and causing Vcc to drop below 3.2V?