Lbn cal values measured 28jan02


     The cal values for lband narrow were measured on 28jan02 in the early morning using the sky/absorber technique. The only difference was that the telescope was not tracking blank sky. The cal on/off times were 10 seconds (drift time for about 1 beam)  so  the on /offs were contaminated by sources drifting through the beam. This data was taken with the radar blanker on for both the sky and absorber (the absorber data looks better than the dec01 absorber data without the blanker on).
    The cals were computed separately by myself and karen O'neil. The values computed by karen were installed 11jul02
retroactively to 01sep01.
Phil's computation of the cals
Comparing phil's and karen's cal values.

Phil's computation of the cals:

    The temperatures used in the computation were:
Tsky+Tabsorber 20 K
Tabsorber 292 K
Treceiver 12 K

Each frequency band was measured 9 separate times on the absorber and 21 separate times on the sky. For each measurement the calon/off-1 spectrum was  computed and then the 9 or 21 separate measurements were cumfiltered to remove rfi. The calValue versus frequency plots show the results.

    The spectra of calOn/Caloff-1 for the 21 sky measurements also shows the jumps do to the sources. Each colored line should be continuous. The vertical jumps at 100 Mhz boundaries are the sources in the on or the off. You can also see the rfi (before filtering) in the 1200 to 1300 Mhz band and the 1500 to 1600 Mhz band. The plot is calon/caloff-1 so the rfi can be in the on, or the off, or both.
    The final plot has the power levels during the measurements.
processing: x101/020128/,,,

Comparing phil's and karen's cal values: (top)

    Karen O'neil separately computed the cal values from the 28jan02 using different rfi excision techniques. The first figure compares the old cals, karen's cals, and phil's cals: The second set of plots compares the gain and Tsys of lbw to lbn using karen's and phil's cal values. All of the calibration scans for lbw and lbn between sep01 and may02 were used. The common frequencies for the two receivers were used: 1300, 1375, and 1415 Mhz. The sources for the two receivers were different so any flux density error do not cancel. Karen's cal values were installed as the current cal values on 11jul02. They will be used for data taken after 01sep01 (to match the new gain curves).