[Gabriele, Elenna]

Today we measured the ISS second loop open loop gain to determine how stable we are at 76W of power. We made use of Craig's scripts and SR785 templates in gitcommon/psl_measurements.

I have attached three measurements we made at 76W. First, we used the nominal gain of 0 dB. Then, we determined that we should reduce the gain in the loop. We tried both -5 and -10 dB on the second loop gain slider. Using a gain of -5 dB places our UGF at around 22 kHz with a phase margin of about 30 deg. This is comparable to Craig's previous measurement at 2W and 30 dB on the gain slider, see alog 61721. If we did not change the gain, we would have a UGF of 33 kHz and gain margin of 5 deg. At -10 dB, we have 12.5kHz and 54 deg.

As a note, these plots correct for the additional 20 dB gain in monitor path.

The results from today are saved in psl_measurements/data/iss_second_loop_olg/ and they are all time and date stamped.