My listening device is car radios.
One is a Ford 3 nights a week, the other is a Toyota 1 night a week.
I drive around the entire city for hours on end.
When I get into the sweet spot of reception for 91.1 I can then A/B the 2 stations.
Both instances the pilot is on.
91.1 distinctly sounds mono on the last time I did this, in the Toyota.
The noise is louder on 107.1 because it seems to be in the L-R sideband, when I listened really carefully I could hear the noise on 91.1 but because it seemed to be in mono, the noise wasn’t as pronounced.
Keep in mind I’m still driving around.