The wireless phone is very fashionable. There is no more to see the number of ads you send us to buy this type of phone. Also in the ads the phone always works correctly and there are never obstacles.
The truth is that many times there is something else. In fact, when companies install a network for wireless phones, they look for the population and not the entire territory. In France, for example, 80% of the population occupies less than 40% of the territory, which means that 60% of the territory is poorly occupied by the telephone network. That's why when you're in the car on a narrow road away from the highways, it's going to be impossible to talk on the phone.
In addition, other phenomena can make telephone communication difficult. Leaves or water from trees (river or marine waters) can break the transmission. Buildings can also multiply the wave and eliminate the signal. The walls of the house can also make communication difficult, etc.