Alfa long recovery after bias changes (on sky)

23 sep08 Total power vs time
23sep08 dynamic spectra
24sep08: long recovery vs alfa rotation angle.

    The bias voltages for alfa were changed on 19sep08 to improve the recovery time from large pulses. On 23sep08 around 14:00 hours data was taken with alfa on the sky to see how long the recovery took. The setup was:
    The 100 MHz Rf filter (1390-1490 MHz) was not used so  the IF/LO downstream from alfa also saw the large radar pulses. This is different from the  pulsed noise tests that used the filter (on the other hand, galfacts does not use the filter).

23sep08 Total power vs time:

    The total power vs time for all beams(.ps) (.pdf) was computed for each .1 second spectra in the 1375 to 1525 MHz band:


23sep08: DYNAMIC SPECTRA: az=360,za=17.23

  Dynamic spectra for the az=360, za=17.23 with adc blanking off were made to show what was present in the band. The processing for the images was:

no Adc Blanking

beam6 Only polA

Notes on the images:

processing: x101/080923/,

24sep08:  Long recovery versus  alfa rotation angle

    On 24sep08 around 17:00 data was taken with alfa and the pdev spectrometer to measure the long recovery time versus the rotation angle of alfa.  The setup was:
Total power vs time  for rotation angles 0,10,..60 of alfa (each page =1 angle) (.ps) (.pdf)
Total power vs time  for rotation angles 0,10,..60 of alfa (each page =1 angle) (.ps) (.pdf)
Dynamic spectra of beam 0 at different alfa rotation angles:
dynamic spectra were made for beam 0 at the 7 different alfa rotation angles. The images have the 1450 image on the left and the 1300 image on the right. This is the same data as the total power plots above.


processing: x101/080924/,

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