Why does a cell tower need to be massive to transmit data to a smartphone but the phone’s extremely small antenna can transmit data back over the same distance?
In: 52
To simplify it a bit, range is basically sqrt(Size1xSize2).
If you halve the size of one antenna the other needs to double to maintain the same signal between the two.
So since we can make the phone antenna/transmitter less powerful and sensitive in exchange for making the tower more powerful and sensitive we go with small phones and big towers. It keeps the big expensive parts on the tower, and phones small and with lots of battery life.
Note “Size” really doesn’t translate directly to physical size, it’s more about antenna directionality/gain + transmit power, and fancy hardware to do stuff like beamforming. But in general using large arrays of antennas, or stuff like a dish require more physical space so it’s close enough.
However if you look at a tower the physical antennas (on common cell phone towers the vertical rectangles up top attached to a triangle frame) , while much large than a phone, aren’t actually that big compared to the tower. The tower itself is used to get the antenna off the ground to keep line of sight between phones and the towers, since it’s really inconvenient to ask you to climb to the roof of the building to make a call 😀
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