Samsung Galaxy S20 can't connect to GSM networks but LTE works
Texte:
I have a strange network connection issue on a Galaxy S20 (G980F): When LTE reception becomes bad, the fallback to GSM (2G network) never works despite good GSM signal coverage. The phone reports close to full bars and tools like Network Cell Info detect the different GSM base stations in the area with good RSSI values, but the phone can't connect to the network (no voice or data). It's not a network provider issue because GSM works fine on a different phone at the same location with the same SIM card (tested with LTE manually switched off) and the cell tower has similar RSSI values on the good phone, so it seems not to be an antenna problem either.
Is it possible that only the 2G ''transmitter'' in the phone is broken but the receiver and antenna are fine, so it can scan for cell towers but never connect? Is it even a thing that only the transmitter can get fried and not the whole baseband chip or at least the band's receiver as well? Or does the phone use two different antennas for 2G transmission and reception and one has a bad contact or something like that? 4G always works fine on the phone if it's available. What else can I check?
Samsung Galaxy S20 can't connect to GSM networks but LTE works
Texte:
I have a strange network connection issue on a Galaxy S20 (G980F): When LTE reception becomes bad, the fallback to GSM (2G network) never works despite good GSM signal coverage. The phone reports close to full bars and tools like Network Cell Info detect the different GSM base stations in the area with good RSSI values, but the phone can't connect to the network (no voice or data). It's not a network provider issue because GSM works fine on a different phone at the same location with the same SIM card (tested with LTE manually switched off) and the cell tower has similar RSSI values on the good phone, so it seems not to be an antenna problem either.
Is it possible that only the 2G ''transmitter'' in the phone is broken but the receiver and antenna are fine, so it can scan for cell towers but never connect? Is it even a thing that only the transmitter can get fried and not the whole baseband chip or at least the band's receiver as well? Or does the phone use two different antennas for 2G transmission and reception and one has a bad contact or something like that? 4G always works fine on the phone if it's available. What else can I check?