Dave, Daniel

(I meant to post this a couple of weeks ago but hadn't gotten around to it.) I compared ~2 hours of the 1PPS signal from the old GPS clock installed in EY to the aLIGO Timing Distribution System's 1PPS signal and found, as expected, a near-constant time difference of order 100 ns (likely attributable to antenna and 1PPS cable length). The jitter, which is the more important feature, was nicely contained to 3 clock cycles, with a standard deviation of no more than two clock cycles (the narrow bands in the histogram are due to the comparator's measuring time difference based on clock cycles).

The 1PPS signal was present from precisely 6-23 19:52:34 UTC (12:52:34 local) to 6-23 21:52:29 UTC (2:52:29 local), a total of just under 2 hours. I'll follow this up with a long-term timeseries and histogram showing the time differences between aLIGO Timing Distribution and the new GPS clocks installed at both end stations.