At a wavelength of 70 centimeters (432 MHz). All via the magic of extremely effective error correcting codes (and fairly rare atmospheric conditions).
Related, I'm amazed that my little $70 WSPR transmitter can push a 20m/14MHz signal from San Francisco to Georgia using only 0.2W, transmitting on a pretty lousy backyard dipole only 10 feet off the ground. True, it's only a beacon ("call sign Kxxxxx transmitting from SF at 200mW"), but still...
Related, I'm amazed that my little $70 WSPR transmitter can push a 20m/14MHz signal from San Francisco to Georgia using only 0.2W, transmitting on a pretty lousy backyard dipole only 10 feet off the ground. True, it's only a beacon ("call sign Kxxxxx transmitting from SF at 200mW"), but still...
WSPR being another Joe Taylor invention https://en.wikipedia.org/wiki/WSPR_(amateur_radio_software)