Early H1 DARM spectra showed strong coherence with the IMC WFS dc readouts, particularly in yaw. In DARM this showed up as a fairly smooth noise bump between 100 and 200Hz. It was thought this was input beam jitter caused by the input beam PZT mount (on the PSL/IO periscope). Since then, low pass filters have been added to the PZT driver outputs to reduce the PZT mount pointing noise. The attached plot shows the coherence between DARM and the IMC WFS dc channels for last night's lock. We no longer see the broadband coherence betwen 100 and 200Hz (though there is some in a narrower band around 175 Hz). But there is significant coherence in other frequency bands -- in particular around 250-270 Hz, and around 350 Hz. The only place that the coherence manifests as a real peak in DARM is at 285 Hz. At least some of this coherence should go away when the input PZT mount is moved from the periscope down to the table surface.