24mar21 monitoring xb rcvr for 4 hrs


After the fact


   The  xband receiver on the p12m telescope was monitored for 4 hours on 24mar21. The setup was:

Processing the data

Total power stability

Total power vs time and right ascension:

    The total power vs time  and ra is plotted for the entire 4 hour session.

    The total power vs time  and ra for the 4 hours (.pdf)

Things to take note of:

Blowup of each 300 second scan 19 to 20 hrs ast:

    A higher resolution plot was made by plotting  the total power vs time and the spectrum of the total power for each 300 second scan from 19 to 20 hrs ast (this was after the galaxy had passed through the beam.

Total power vs time and spectra of total power for 300 second scans (.pdf)

Things to take note of:

processing: x101/210324/xbmontp.pro

Using the cal to compute Tsys across the band.

    A cal is installed via the coupler before the 1st amp. 30 second calON, calOffs were done every 60 minutes during the 4 hour period.
We have not yet done a hot/cold load test to get the actual temperature of the cal across the band. Felix used the diode, cable loss, and coupler properties to come up withy 45Kelvins. This was used (across the entire band) when computing Tsys. When we get more accurate measurement of the cal, we'll redo the tsys measurements.

Combing the 7 freq bands

    There were 7 172 mhz frequency bands covering xband. They were spaced by 164 MHz . To compute tsys:

The plot shows Tsys vs frequency for the 4 calon,offs taken during the 4  hour period (.pdf):

Things to take note of:

processing: x101/210324/xbmoncal.pro

Looking at the rmsbychannel  for the cal off scans.

    The rms by freq channel was computed for each of the 300 second scans after 19:00 hours (the galaxy had passed). The computed value was then divided by the average of the frequency channel so the radiometer equation could be used:

The plots show the rms by channel for each 300 scan scan after 19:00 hours (.pdf)


processing: x101/210324/xbmontp.pro,xbmoncal.pro

12meter page