Jeff and other calibrators have been thinking a lot lately about whether having the two Pcal X/Y comparison lines so close together causes issues for our TDCFs.  Jeff made a fix a week or so ago in alog 68479 to ensure there was no significant detrimental coupling. However, to assure myself, I turned off the PcalX 410.2 Hz line (after following Louis' suggestion of touching base with Dripta and Tony).  The comparison line was off for about an hour and a half, and (with Jeff's previous work in place) taking it away seems to have no obvious effect on the measurement of kappa_c or the darm cavity pole, as shown in the attachment.  I have since turned the comparison line back on.