Some additional data:

Here is a screenshot of the PLL feedback spectrum with and without KOACH on, taken in this after noon. The broadband structure from 1-100 Hz and a peak at around 200 Hz disappeared as we switched off the KOACH air system. Also, when the KOACH is on, we see high coherence in the same frequency band, indicating somehow the wind couples to the PLL.

By the way, we believe that noise 1 Hz is free-run frequency noise of the Prometheus laser.

The data is stored in the xml format at:

/users/Commissioning/ALS/PLL/ALS_PLLX_with_without_KOACH_20181031.xml