A full scan of the MPI flip mirror
by Michael Olberg, post on Wed 06 May 2026The MPI flip mirror was driven back and forth over its full range of encoder positions while recording IF power. This allows to properly derive the position of the MPI cold load by fitting the resulting power vs. position relation.
Optimization of the SWI RU FS receivers
by Michael Olberg, post on Sun 03 May 2026Using an iterative procedure, we tried to optimize the settings of both receiver channels in order to get best possible performance at all frequencies.
Another look at the calibration of the internal RU load.
by Michael Olberg, post on Wed 29 April 2026Using the linear relationship between recorded power and load temperature, we take another look at the data from the RU load calibration measurement.
Tunings of all frequencies at two different LO temperatures
by Michael Olberg, post on Thu 23 April 2026We repeated the measurement from 16 April at two different LO temparatures.
Repetitions of Tunings of all frequencies
by Michael Olberg, post on Tue 21 April 2026We repeated the measurement from 16 April in order to check the reproducibility of the noise temperatures.
Second calibration of MPI cold load against internal RU load.
by Michael Olberg, post on Tue 21 April 2026Again, the cooled down receivers were tuned at 11 selected frequencies in each band. Using the MPI hot and cold as well as the internal RU calibration load, the loads can be combined in three different ways to calculate the system noise temperature via the Y-factor method. This time, extra care was taken to make sure the RU flip mirror reached the correct positions during movement.
Calibration of MPI cold load against internal RU load.
by Michael Olberg, post on Thu 16 April 2026The cooled down receivers were tuned at 11 selected frequencies in each band. Using the MPI hot and cold as well as the internal RU calibration load, the loads can be combined in three different ways to calculate the system noise temperature via the Y-factor method.
Tunings of all frequencies with cooled down receivers
by Michael Olberg, post on Thu 16 April 2026The cooled down receivers were tuned at all frequencies in each band. Using the MPI hot and cold load the system noise temperature was calculated via the Y-factor method.
First tunings of cooled down receivers
by Michael Olberg, post on Wed 15 April 2026The cooled down receivers were tuned at 11 selected frequencies in each band. Using the MPI hot and cold load the system noise temperature was calculated via the Y-factor method.
Temperature logging of the receiver unit during testing
by Michael Olberg, post on Wed 15 April 2026A description of how temperatures are logged during the receiver test campaign.
Further bias scans of the 300 GHz doubler of the 1200 GHz receiver
by Michael Olberg, post on Tue 31 March 2026The bias scan of the 300 GHz doubler of the 1200 GHz receiver was repeated at three different bias settings of the 600 GHz doubler.
Bias scan of the 300 GHz doubler of the 1200 GHz receiver
by Michael Olberg, post on Thu 26 March 2026First bias scan of the 300 GHz doubler of the 1200 GHz receiver
Day 2 of bias scans of the 300 GHz doubler
by Michael Olberg, post on Tue 24 March 2026Further bias scans of the 300 GHz doubler.
Bias scan of the 300 GHz doubler of the 600 GHz receiver
by Michael Olberg, post on Fri 20 March 2026The 300 GHz doubler was scanned from -5.0 to -1.0 V and current and power recorded.
How to communicate with the Arduino
by Michael Olberg, post on Wed 18 March 2026A short note on serial communication with the Arduino board, which is interfaced to a potentiometer in order to get positional information on the RU flip mirror.
FDM full scan across all frequencies
by Michael Olberg, post on Thu 12 March 2026The FDM was tuned across all possible frequencies at selected attenuator settings in order to produce the final FDM calibration table to be used during RU FS tests.
FDM scanning across limit of tuning range
by Michael Olberg, post on Wed 04 March 2026We tuned the FDM across 26.381250 GHz, which should be the upper limit according to the User Manual.
FDM current issues
by Michael Olberg, post on Sat 28 February 2026Having a closer look at the currently available tabulated FDM outåut power as a function of frequency and attenuator settings, a number of issues become apparent which need yo be resolved.
TRR #3
by Michael Olberg, post on Wed 25 February 2026The third TRR discussed FDM calibration and possible RU tuning algorithm.
FDM power vs temperature
by Michael Olberg, post on Tue 24 February 2026The FDM was tuned a hundred times to three frequencies at eleven attenuator settings. During the measurement the FDM warmed up from 38.6 to 46.5 degC. The power drifted only marginally with respect to the temperature.
FDM calibration
by Michael Olberg, post on Mon 23 February 2026The FDM was tuned to all frequency/attenuator settings in our database, in order to check if old power readings could be reproduced.
Serial Communication
by Michael Olberg, post on Tue 17 February 2026Update of FDM serial communication API and definition of FDM switch-on procedure.
TRR #2
by Michael Olberg, post on Mon 16 February 2026The second TRR provided the needed documentation for the serial communication API for the FDM. Summary of the communication protocol. Agreed upon switch-on procedure.
TRR #1
by Michael Olberg, post on Wed 28 January 2026The first TRR reported on the preparations for the upcoming SWI RU-FS test campaign.