I know that some amateur radio are using some frequencies that are reflecting on the ionosphere to transmit data over super long distances. I am wondering if it is possible, without an insane lot of power and with relatively portable antenna (on a reduced model of boat that would be about 2*3 meters) to transmit data in this way over at least 7500 kilometers ?
EDIT : Finally, the boat might be smaller : 1.6 meters on 0.6 meters. This boat might have an AI so I think that it wouldn't be that problematic if the connection was lost at some moments. The minimum of data to transmit is instructions for the boat to tell it where to go, but it would be great to transmit photos and videos. I am not a licensed amateur radio operator.