We took a few minutes to do excitations on HPI HAM1+HAM6 before going back to observing.  This was to follow up the measurements made in 34623.   Robert observed that some of the upconversion that we have been having in DARM in times of higher 3-10 Hz ground motion has harmoincs of 11.6 Hz, so one suspicion could have been that this is a multiple of the tip tilt resonance around 6Hz, and this would have been missed by the excitations that concentrated on 10-40Hz.  However, we found nothing resembing this up conversion.  As we knew HAM1 motion does get into DARM at lower frequencies. (probably through CHARD)