the antenna is not the reason for the "louder and clearer" audio noted by some when testing antennas.
it cant be.
it comes after the radio and all the modulation "work" is already done by the time it gets to the antenna.
even if one antenna was "louder" than another, you would never notice it because of a little thing called the AGC (automatic gain control) circuit inside your receiver.
its job is to keep the audio level constant whether the signal is an S-3 or an S-7.
the question is, how well does it do its job.
i think it does its job pretty well, but its not perfect.
i would say that the perceived increases in loudness that are being noted by others are a result of the AGC not "clamping down" fast/far enough.
as for the differences in the signal strengths; since all of the antennas we are discussing are within about 2db of eachother, the differences probably have more to do with the differences in the matching systems of the antennas in question.
i would think that the IMAX's matching system is more lossy than the gain masters, which could easily account for the 3 db difference noted in these tests.
LC