Dana, Sheila
I plotted how the DCPD matrix has changed over the last eight years in the attached figure (DCPD_sums_and_nulls_8years). I've also included zoomed in snapshots of all the major changes within this time span with the dates and times shown (changes 1-7 attached below). For each one of these jumps in the matrix values, I checked the alogs for that day and attached any potentially relevant ones explaining what was going on at the time below:
change 4 (1)
change 6 (1)
Jeff (alog 29856) and Jenne (alog 30668) both made measurements of the imbalance between A and B of the OMC DCPDs, i.e., the ratio of B to A, back in 2016 after the OMC was replaced. I measured this ratio just now to see if this value has changed greatly since then. I targeted the XPCal line at 102.13 Hz at GPS time = 1386096618 s and measured a value for B/A = 0.963 +/- 0.001. Jeff found B/A = 0.958 and Jenne found B/A = 0.969, so it seems this imbalance has not changed much since the OMC was replaced. See attached figure for transfer function.
