I agree adding power seems to do what you suggest. However, and this is just a guess gamegetter, since I can't see RF signals. But, you could also notice a difference in audio between two antennas at one moment in time simply due to conditions where signals arrived as line of site signals on one antenna, and with the other antenna the signals were reinforced by the addition of some reflection on the Earth's surface or objects, or from high angle reflections from the sky.
IMO, we are not likely to be able to observe such responses...unless at least one of the stations has two antennas up, connected thru a switch box for rapid switching, and the conditions are just right. To be fair, Bob85 recently posted information in another thread on this forum about their setting the radio's RFG back, in order to see better responses, and I believe that is possible in many cases. So, that too must be considered as a possible "cause" or "NO," in all such cases as I described above.
Otherwise I agree, it probably takes a lot of added power to produce a noticeably stronger audio signal in a general sense, and of course distance probably has much to do with such a phenomena being noticable. However, I might believe the responses are similar, IMO the causes are different.
