Do you want to make 300 Gal of fresh water
over a 24 hour period (12.5 Gal./Hr.), or in some other shorter period?
Side Band (SSB) range is generally reliable to a 150 mile maximum (2-3mHz MF band) , though HF band can sometimes reach thousands of miles. I suspect you’ll have to use Short Wave (amateur, or HAM) radio, or satellite
telephony for 3000 mi. communication range.