True. It would take more than an R3 or X1 class flare to really impact the parts of the RF spectrum that cellphones operate at. These types of flares can cause one or 2 hour long HF blackouts effecting things like shortwave HAM radio, shortwave broadcast radio, CB radio, and other radio services that operate at frequencies at or below 35 MHz. Besides that, my T-Mobile network connected (MNVO) phone was never effected.

True. It would take more than an R3 or X1 class flare to really impact the parts of the RF spectrum that cellphones operate at. These types of flares can cause one or 2 hour long HF blackouts effecting things like shortwave HAM radio, shortwave broadcast radio, CB radio, and other radio services that operate at frequencies at or below 35 MHz. Besides that, my T-Mobile network connected phone was never effected.