On Thursday and Friday, Emily, Terra, Vinny, Dominick, Brian and I got PEM channels going in the PSL, ISCT1 and Y-end. Dave got these channels into the frames. On Saturday, Daniel and I ran the HIFO and found coherence to be especially strong with sensors at the PSL periscope and ISCT1. Today I ran the HIFO with the PSL fans shut off, except for the makeup air. Figure 1 shows a substantial broad band improvement in the HIFO-Y error signal from shutting these fans down. We intend to run with the makeup air at a low rate, but I didnt feel any difference in the flow out of the PSL feed-throughs between 100%  and 1% settings of the makeup air so we will have to look into this to make further improvements. The broad peak at 70 Hz is coherent with ISCT1 motion so we will look into this this week as well.