I’m trying to gain a better understanding as an in-shore fisherman of how VHF marine radios work and would appreciate if someone could answer this question.
Scenario: I transmit a radio check or distress message on Channel 16 to the Coast Guard over my handheld 5W Cobra VHF Marine Radio 1/4mi from shore, the coast guard can hear me and responds.
Question: Is my low-power message automatically relayed by the Coast Guard station over 25W or higher signal so that a boater 20 miles from shore could hear my message? Or, is it more likely that the Coast Guard heard my message because I’m close enough to shore, but my 5W transmission was too weak to be picked up by that boater 20 miles offshore (let’s say he has a fixed-mount 25W radio)?
I’m not looking for “why would you do this” responses, I’m looking to better understand how tx/rx works and more specifically how far a 5W radio transmitting over CH16 near shore will realistically be heard by other boaters.
Thanks so much.