Jeff, Oli

I think there is an issue with satamp S1100105, which was taken out from SR3 M2 back in October as part of our whitening filter upgrade satamp swaps (87620). I've put together some plots to show what the noise looked like on SR3 M2 before and after S1100105 was swapped out for an upgraded satamp (pdf). You can see in the Old plots that below 1 Hz there is a lot of noise that gradually slopes down; Jeff mentioned that it looks like a noise floor.

I found this out as I was making satamp swap comparison plots and found that no matter what time I chose as my 'before' time, the noise at lower frequencies was always very high, even after removing the coherent seismic noise.
I looked through many channels in ndscope and tried to find any differences between the before and after times that could possibly explain this noise but found nothing.
I have informed Fil and Marc and they will be testing the satamp.