I made a break-out board that allows connecting Rai's 1nV/rtHz pre-amp to the coil driver output (without acting as antenna...).

A preliminary look at the noise out of the ITMX PUM coil driver is:

- We have a 10Hz comb, due to  ~10msec duration bursts every 100msec. THis seems to be picked up radiatively - the dominant contribution is actually coming from the cable to the coil (i.e. it is present even with the coil driver disconnected, measuring the voltage across the coil)

- The noise out of the coil driver, terminated with 50Ohm right after the breakout box, is ~2.8nV/rtHz at 15Hz.

- With the coils connected, between the 10Hz comb, I get roughly 20nV/rtHz. However that noise was somewhat fluctuating.  Assuming all test masses have ~ the same noise, that will increase the current 24W GWINC curve by ~x2 below 30Hz, but it is a little short of explaining our noise.

- THere is also a significant amount of noise above ~10kHz - presuimable from the same 10msec bursts - more to come.