Galfa pixel 4a/6a switched jul05


    The cables for pixel4a and pixel6a (count from 0)  from the distribution amplifiers in the receiver room to the galfa spectrometer were switched on 11jul05  (after 8 am AST). They were returned to the normal order on 19jul05 (12:00 AST). The data going to the wapps were never switched. This meant that when  looking at the galfa data off line:

This was the same problem that occurred back in may05. The distribution amplifiers in the control room were removed to install the second fan (the first was installed back in may05). When the chassis was reinstalled, the cables leaving the chassis (going to galfa) were switched.

    Continuum sources drift/move through the alfa beams at different times since the beams point at different locations in the sky.  600 second total power scans showed that pixel 6a and pixel 4b had continuum sources moving through the beams at the same time (6b and 4a also showed this).

    On 11jul05 a2011 took data using the wapps and using galfa. The plot shows the total power drifts versus time after the cable switch (.ps) (.pdf). Each pixel is plotted in a different color.

This problem only affected the galfa spectrometer. The wapp data was never switched.


processing: x101/050719/