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Comment on SpaceX Has Launched Starlink's First Direct-to-Smartphone Satellitesparent

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A really powerful satellite has a power supply of about 1 kilowatt.

Assuming perfectly efficient antennas and a single spot beam with a diameter of about 300 kilometers (realistically, it's going to project dozens of these for a total of several thousand kilometers, but let's stick with the worst case here), that's an area of about 200 000 square kilometers to cover with that one kilowatt, i.e. 5 milliwatt per square kilometer.

This is roughly the same amount of maximum EM radiation emitted by a single AirPod – now spread that over one square kilometer.

Compare that with a regular LTE or 5G cell with a cell radius of at absolute best 30 kilometers (but often much, much less, e.g. 1 kilometer) and an unusually high EIRP of 50 watt, and you get 17 milliwatt per square kilometer. Or take an AM radio station: These transmit with 50 kilowatt and are much closer to people, sometimes located on rooftops in densely populated cities.

Realistically, what arrives down on earth is probably still a few orders of magnitude less than that and just at the edge of the noise threshhold for the phone. It's not exactly a beam weapon.

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