Following along Gabriele's work to understand noise from modulation of low frequency lines in DARM, I made a noise comparison today using DARM with no calibration lines. We stayed in NLN CAL MEAS (all cal lines off) long enough to get a good measurement of GDS CALIB STRAIN with no calibration lines. I compared this with GDS CALIB STRAIN NOLINES during times when the calibration lines were on. See attached plot. The difference is small, but I think it is evidence that we are seeing some of these low frequency peaks like the 2.6 Hz modulating the calibration lines and causing excess noise. Even though the NOLINES channel has the calibration lines subtracted, we do not subtract any bilinear effects from the calibration lines. I grabbed a couple different random times from recent locks to make sure I wasn't getting fooled by transient noise.

Our range jumped up to 147-151 Mpc during times when the calibration lines were off, which I think is a combined effect of the additional sensitivity from no lines and also no other peaks from line modulations. Usually our range is around 145 Mpc.