I get how the phone can download from the cell tower, because cell sites use 20-50W directional antennas, much more powerful than the phone, so they can cover a large area.
But the phone’s antenna is omnidirectional, usually 1W max. That’s as powerful as a Wi-Fi access point. So how can it reach the cell site 2 miles away? Is it because cell site antennas have high gain, so they can pick up a very faint signal?
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Cell phone towers have ***much*** larger antennas and much more power available for signal amplification and processing compared to a handheld phone. They also tend to use a number of directional antennas to pick up signals from all directions, which helps their performance.
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Really what’s going on is the cell tower has just a lot of tech that makes it really good at cleaning up the noise in your signal and boosting it. You might think because the cell tower is transmitting at much higher power it has much higher range than your phone, but honestly transmit power falls off at a rate of the square of the distance between you and the entity receiving so it’s not a huge deal.
You get across the entire solar system with 20W of power. Most part done by the receive antenna here…
Cell tower antennas power is lower than that, and a cell phone can go up to 4w (depends on the country, in the US it is probably more).
In any case, it can because the receiver has a very high sensitivity in both directions, and it is digital, so we can (and do) use TONS of error checking and correction, plus the data is sent multiples times. At some point it just goes through.
I can reach about 15 miles on my lora setup. It can only emit at 25mW max, and the signal power after antenna must not go over 14dB.
They can change the modulation and code rate to match the quality of the signal.
They “speak” in a condensed manner when the signal is good, and stretch and dilute the signal when the reception is poor. To put it in more human terms (English is not my native language, but I try) : When the signal is good, they may say something like:
>People can stand less heat and humidity that we thought. It’s 31°C wbt, not 35°C.
Or they may say something like:
>Humans can’t endure temperatures and humidities than previously thought. It has been widely believed that a wet bulb temperature of thirty five degrees celsius at 100% humidity was the maximum a human could endure before they could no longer adequately regulate body temperature. But a new study found that the actual maximum wet bulb temperature is lower, only thirty one degrees celsius, or eighty seven degrees fahrenheit at 100% humidity, and people risk heat stroke or even death at higher temperatures.
And when even that is not enough to adequately understand despite the poor signal, they can switch to
>People: Papa, Echo, Oscar, Papa, Lima, Echo; can: Charlie, Alpha, November; stand: Sierra, Tango, Alpha, November, Delta; ….
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