[Heather Fong, Sheila Dwyer, Karl Toland, Vaishali Adya]

We went back to EY on Tuesday to reproduce our measurements 34540 . We did a few measurements with the Illuminator powered off followed by the PDs. The coherence with DARM didn't change by a significant amount.

The channels we looked at were :

1. H1:PEM-EY_ADC_0_14_OUT_DQ (+24V)
2. H1:PEM-EY_ADC_0_15_OUT_DQ (-24V)
3. H1:PEM-EY_ADC_0_16_OUT_DQ (+17V)
4. H1:PEM-EY_ADC_0_17_OUT_DQ (-17V)

Here is a list of the frequencies that show up apart from the known calibration lines and multiples of the power lines :

281.875, 282.375,284.75,280.25,279.75,279,277.125 Hz

When we turned off the Oplevs however we noticed an additional peak at 33.37 Hz.

This measurement is consistent with what we saw in 34540.