It wasn't in my hands, but would think it was the current level being measured at the time of the photo, with the bar being the peak that is displayed, like shown here:
Yeah, as I said I can readily grasp the concept for measuring signal levels on a legacy LNB like that, but its the SWM type that's still got me somewhat confused. If I'm properly understanding how the agc circuitry functions for the SWM LNB you wouldn't even be able to see a -38.8 dbm signal level like in that example since the agc circuit would amplify it by ~9 db for its usual limit of -30 dbm nominal output.
Be interesting to see how the AIM meter is able to somehow "see through" the masking effects of the agc to derive the actual RF power levels on the input side of the integrated SWM.
BTW: What's the prominently displayed "-43.4 dbm" level at the bottom center of the meter screen mean?
Maybe by the end of next week I can have some of the data/testing done by who's getting their AIM.