Yes, but once they dismantled it and didn’t find any people, they would rule that out and move on to the next most reasonable explanation. So the method might seem ridiculous at first glance, but it still yields results nonetheless.
The problem that McKenna was highlighting is that science has a bunch of unstated assumptions that impede actual fact-finding.
In the case of the radio the key was that there was a whole civilization (out of sight and not measured by instruments) that would need to be understood to figure out what was happening.
_That_ is the UFO issue in a nutshell.
The assumptions must be thrown away before a serious investigation can be started.