Adding 10 db amp in front of alfa pixel2a,b mixer


    A 10 db amplifier was added in front of the upstairs mixer for pixel2 polA and B on 05apr05. This was done to test the oh filters that were being installed. Project a2010 ran (centered at 1385 Mhz) before and after this amplifier was installed. 600 second long drift scans were  taken for 5 to 6 hours a night. There is a single cal fired after each 600 seconds. The median system temperature for each strip was scaled to kelvins using the cal deflection. The plots show the change in the system temperature in pixel2 (.ps)  (.pdf) because of the change:

  1. Top: Tsys for pixel2 is divided by the average Tsys for the other 6 pixels. Black is polA, red is polB. Tsys for polA remained constant. Tsys for polB decreased by 13 percent.
  2. Bottom: Tsys (degK)  is plotted for each of the days. polB was about 1.5 K higher than polA. After the amp was installed they were the same value.
The 10 db amp improved the system temperature for polB appreciably.
processing: usr/a2010/mondata/apr05/