Re:Can someone explain this? (Score 4, Insightful)

It depends on how well are you able to receive. There's a parameter that is named the receiver sensitivity and that's the lowest power that it can receive and still get the correct data. If you have a receiver circuit with sensitivity of let's say -90dbm and that allows you to reach 0.1 miles, if you have another device that has a sensitivity of -93dbm that will allow you to reach 0.15 miles without changing the transmit power. The sensitivity depends on how noise inmune is your receiver to noise and that depends on the radio standard used.