19nov09 oscillations from bias box





     When alfa was reinstalled in nov09, oscillations were seen in the output signal. These were traced to the bias box. Part of the "work" done on alfa was to move the capacitors in the bias lines from inside the dewar to outside. This may have affected the bias circuit causing the oscillations (or maybe they were there before at a lower level).

    On 19nov09 we transmitted a sine wave from the control room to see if the 2.5 MHz oscillation frequency would mix with our sine wave.  The setup was:

The plots show the sine wave and the oscillation frequency mixing in (.ps) (.pdf):


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