Symptoms
- Static, choppiness, or dropped calls right after getting a new phone
- Data and texting work fine but calls sound bad
- Problem happens in areas where the old phone worked fine
- Issue appeared after switching carriers or SIM cards
Likely causes
- CommonSIM card not fully activated or provisionedA newly inserted SIM sometimes needs time or a manual step to fully register with the network.
- CommonMissing carrier settings updateNew phones may need a carrier settings update pushed the first time they connect to the network.
- PossibleNetwork band or VoLTE setting misconfiguredSome phones need specific settings enabled to use the carrier's full voice network.
- PossibleCase or screen protector improperly covering an antenna areaCertain phone models have antenna lines that a case can block if misaligned.
- Less commonDefective SIM cardA damaged or faulty SIM card can cause poor call quality despite good signal.
What to do
- Restart the phone to let it fully re-register with the carrier network.
- Check for a carrier settings update in Settings > General > About (iPhone) or similar Android menu.
- Confirm VoLTE (Voice over LTE) or HD Voice is enabled in network settings if your carrier supports it.
- Remove any case and test call quality without it to rule out antenna interference.
- Try the SIM card in another phone briefly, if possible, to rule out a defective SIM.
- Compare call quality with the old phone in the same location to isolate whether it's the phone or the network.
- Contact your carrier to confirm the SIM and line are fully activated and provisioned correctly.
- If quality remains poor after activation checks and updates, request a replacement SIM from your carrier.
Tools and parts
Replacement SIM cardSearch: “carrier replacement SIM card”
When to call a pro
If call quality stays poor after activation and settings checks, ask your carrier for a replacement SIM or a line-level diagnostic.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.