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Message ID: 181     Entry time: Sun Nov 13 10:11:19 2016
Author: Gabriele 
Type: General 
Category: Noise hunting 
Subject: Noise due to air 

The plot below compares the QPD signal spectra in different configurations (roughing pump on/off, air on/off).

The noise below ~<2kHz is making very hard to measure the Q of the first mode at 1100 Hz

The main source of noise are the clean air filters. I switched them to minimum for the moment being.

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