SIM800L network date delivery fail

Hi, I need a “little” help about (how & when & why) network delivery date/time (to use with +CCLK).

I made some tests and get some strange behaviors.

X antenna (+CSQ = -80dBm) get date after GSM started (power ON).
Y antenna (+CSQ = -80dBm) NEVER get date after GSM started.

I tried all commands, CLTS, CBAND, CANT, but nothing make Y antenna work.

Ps: Yes, Y antenna work with nicelly signal, but only can’t obtain date.

Why this happen? How can I force network date delivery (yes, I know is network-dependent)?

If you are sure that the antennas are the only factors that influence that behavior, maybe the different topologies have different dominant frequencies emitted by different antennas on the provider side. In that case, you might be effectively connecting to “different” services, one of which provides date-time.

Hi @viedana, Im note sure about antenna is the only factor, both antennas are equals, basically, only the cable length changes (15cm and 11cm). I already use this antennas before, but now, someones never get date. (15cm cable not work)

If what you tell’s is true, AT+CBAND should work (selecting the same band), and this not occur.

Do you have more ideas?

What do you mean? Are you changing anything else besides the antennas? Or are you swapping them onto the same sim800l without changes to the software or hardware?

No, I just swapping antennas, but I really dont know about “behind scenes” (operator band, etc). I will do some updates on the problem above. The antenna below are the same, just the cable changes.

I swap to cable A (11cm) with antenna X, work.
I swap to cable B (15cm) with antenna X, not work. (This cable are the project defaults that I bought)

Some rares cables B work nicelly, others, work when I turn antenna around.

I have observed that the modules like SIM7000 and SIM7500 only give network date time in 2G mode when CNMP is set to 13. But SIM800 series modems always give network date time without any problems.
I follow the below steps,
AT+CLTS=1

You can do AT&W to make this permanent.
Wait for some time and issue AT+CCLK?