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Entry  Tue Dec 4 23:16:35 2007, tobin, Update, PSL, ISS 
    Reply  Wed Dec 5 17:49:57 2007, tobin, Update, PSL, ISS rin.pdf
       Reply  Wed Dec 5 18:22:03 2007, tobin, Update, PSL, ISS dark noise sense_noise.pdf
          Reply  Wed Dec 5 20:32:51 2007, tobin, Update, PSL, ISS dark noise 
             Reply  Thu Dec 6 19:30:43 2007, tobin, Update, PSL, ISS dark noise - 60 Hz! iss.pdf
                Reply  Fri Dec 7 19:14:30 2007, tobin, Update, PSL, ISS dark noise - ground loop enlightenment 
Message ID: 183     Entry time: Fri Dec 7 19:14:30 2007     In reply to: 177
Author: tobin 
Type: Update 
Category: PSL 
Subject: ISS dark noise - ground loop enlightenment 
My alleged 60 Hz harmonics were all from a ground loop created by connecting the SR785 ground to the ISS circuit ground; they disappeared when I set the SR785 input to "floating ground." doh!

I modified the ISS PD's to have a 100 ohm resistor in series with the output (in place of 20 ohms). The diodes are again in place on the table, ready for action.
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