The phone does not need cell service to work.
Yes, as long as you are within range of other gotenna devices.
Yes, you will need a device to connect it to.
Point-to-point range depends on your environment, and no situation is exactly the same. That being said, more open terrain often allows for greater range; line-of-sight can also help but is not required. Plus: you may be able to extend your range through other goTenna Mesh devices by relaying! In general, you can expect up to 4 mi (6.4 km) point-to-point range in open environments such as plains, desert, beach-side, etc. Expect up to 0.5 mi (0.8 km) point-to-point range in congested areas such as cities, mountains, ravines, thick forests, etc.
Point-to-point range depends on your environment, and no situation is exactly the same. That being said, more open terrain often allows for greater range; line-of-sight can also help but is not required. Plus: you may be able to extend your range through other goTenna Mesh devices by relaying! In general, you can expect up to 4 mi (6.4 km) point-to-point range in open environments such as plains, desert, beach-side, etc. Expect up to 0.5 mi (0.8 km) point-to-point range in congested areas such as cities, mountains, ravines, thick forests, etc.