Une info lue sur le site : http://www.loratracker.uk/
In an urban environment the limit of reception was 1km, yet with the exact same transmitter and receiver and clear line of sight, the reception distance was 1200km, probably more.
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Thus whilst you might get 400KM with LoRa from the ground to a high altitude balloon, do not be surprised if at ground level in a city you get 400M or less.