Ripple in the lbw rcvr near 1400 Mhz

aug 04


    There has been ripple in the lband wide bandpass near 1400 Mhz during the a1861 run of may04 and during the a1914 run in aug04. Looking at the dynamic spectra of the 1 second records, there is a broad change in power over  a few mhz for up to 300 seconds. It is not a narrow feature sweeping across the band. Both experiments used the interim correlator.

Data taking setups:

    The a1861 data did on,off position switching using 300 1 second records. The first two sbc were polA, polB at 25Mhz while the last two sbc were polA,polB at 12.5 Mhz. When they observed above 1370 Mhz, the 1320 hipass and 1370 hipass wave guide filters were installed. When they were below 1370 and toward the ends of the runs, the 1370 hipass was removed.

    Project a1914 used the 1st two sbc for polA and polB at 25 Mhz. The last two sbc were set to 12.5 Mhz bandwidth. On,off position switching was done with 300 1 second records. For 01aug04 and 02aug04 the 1370 hipass and the 1320 hipass wave guide filters were installed.

Plots of the data:

a1861 may04 on/off-1 a1914 : 01,02 aug04 (on/off-1)