system
Given the following post, respond as if you're commenting on Reddit:
human
How can a tiny, low-power cell phone send a text through a signal that can be heard from miles to a tower that can send it to the recipient who could be almost anywhere in a matter of seconds?

Please use as excruciating of detail as possible. I really want the nitty-gritty.
gpt
I imagine this is still higher level than you want, but here it is!



> tiny, low-power cell phone send a text that can be heard from miles to a tower

Higher frequency signals -- in the Megahertz range -- travel further than lower frequency ones, due to a variety of properties including higher reflection off environmental surfaces.  However, higher frequencies cost more energy to generate -- but, as Schimmelreiter already explained, this energy cost can be mitigated by lowering the amplitude.  
Thus a phone will transmit a high frequency, low amplitude signal, by pushing energy up and down a short antennae hidden in the phone case.  

This signal is a wave at a fixed frequency, and thus it has one property that can be subtly modulated to encode information: the amplitude.  Imagine a sine wave with a slight wiggle in the signal -- that wiggle can be treated as morse code, or binary code, or far more complicated codes, and within that wiggle your text message can be transmitted from your phone to the tower.



>a tower than can send it to the recipient who could be almost anywhere

The tower you are sending a message to is just connected to a big network, much like your laptop is connected to a router sitting somewhere in your house. The destination phone, the friend you are sending a text message to, is also connected to some tower somewhere else, which is also communicating with the same network.  You could imagine that when the tower recieves your text message with desintation "Friend's phone", it asks the network if anyone knows where "Friend" is -- and the tower nearest your friend answers.  These two towers exchange information, and then the tower nearest your friend sends them the text message in the same way that your phone sent a message to the tower.  Then, they have the message!



>in a matter of seconds

Cell signals are electromagnetic waves.  These propogate at practically the speed of light -- practically instantaneous.  Thus, the few miles between you and your nearest cell tower are covered by the signal in microseconds.  After hitting the tower, various methods of communication are used between your tower and your friend's tower -- but they're all, again, practically instanteous since they are all electrically based.  Thus, the only limiting factors in this travel time are really just the time it takes to process the signals and for the towers to communicate and find each other.