i read this question before asking. how does a cell phone transmitter work?
i am very confused about Google Project Loon. I understand the balloons will be transmitting LTE from 20KM up in the sky.But i am sure there will be enough transmission power in the balloon so the signal can reach the ground. But how does a consumer handheld LTE device going to be able to transmit 20KM up to the sky and still be able to keep battery life?
What i am missing ?
Best Answer
Far field EM waves don't stop propagating until something absorbs them or changes their direction - that's why we can observe stars. Range problems on the ground come from curvature of the Earth and accidental shielding that occurs in various objects and structures.
Radio is a lot like light, except that many more things are effectively transparent to radio. Due to some other physics problems, though, passing through an ungrounded metal structure destroys the original signal and repeats it with less than optimal conditions, leading to problems on the ground. Passing through a grounded metal structure can destroy the signal entirely.
Project Loon is a practical method to take our best wireless broadband technology and lift it to where it has better line of sight to consumers.