We are using the HL7800/HL8548/HL7688 modules with a SierraWireless SIM. However, all the HL modules have the same issue in that they don’t always connect to the best cellular network. How do we get the HL modules to connect to the best network.
For example, with the HL7800 we have two cellular providers nearby, both with LTE Band 28 (700MHz). The modem will connect to either of them.
Here is the good network (Vodafone NZ):
- Tower is line-of-sight 100m away.
- ppp connects and there are no issues. Near 0% packet loss.
- Below is the output of the relevant AT commands.
AT+CSQ +CSQ: 31,99 AT+KCELL=0 +KCELL: 1,5,35f010,86601,460,41216,88,28,2 AT+KBND? +KBND: 0,00000000000008000000 AT+KSRAT? +KSRAT: 0
The poor network (Spark NZ):
- Tower is hidden but also about 100m away.
- ppp may connect, when it does there a huge packet losses.
AT+CSQ +CSQ: 14,7 - both values fluctuate a lot AT+KCELL=0 +KCELL: 1,5,35f050,75479,460,41216,88,28,2 AT+KBND? +KBND: 0,00000000000008000000 AT+KSRAT? +KSRAT: 0
Once connected to the poor network the modem modules will not change to the better network. Even after a power cycle.