I think in the past they sent out "free" receivers to areas with low coverage: https://www.flightradar24.com/blog/making-the-flightradar24-network-even-stronger

I think in the past they sent out "free" receivers to areas with low coverage: https://www.flightradar24.com/blog/making-the-flightradar24-network-even-stronger/ https://www.flightradar24.com/blog/making-the-flightradar24-... while the other tracking sites tend to be enthusiasts with their own hardware only.