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Sections:

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History:

• 15mar06: sbn cal values remeasured at 2380 and 2280. Installed 10apr06, backdated to 14oct03.
• 14oct03 turstile stubs switched. Also reversed  rf cables so polA is still polA downstairs. This is to put the "better" amplifier for the OC echo for the radar experiments.

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Calibration measurements:

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Miscellaneous:

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May03 to Feb04  fit GAIN CURVES to calib data.  (top)

    A gain curve was fit to the sbn gain data  taken between 01mar03 and 29feb04.This data is described below.The plots show the gain data (black) and the fits (red) for 2380 Mhz.This gain equation was installed on 09mar04.

• Fig 1 shows the az,za distribution for the data. The fit uses a linear fit out to a za of 14 degrees. Above 14 degrees it includes a za^2 and za^3 term. It also has 1az, 2az, and 3az sin, cos terms.
• Fig 2 top plots the gain data and the fit to za.  The fit equation is plotted with the sigma for the fit (in K/Jy). T
• Fig 2 bottom plots the fit residuals (data-fit) vs za.

    The routine gainget() or corhgainget() will now return the sbn gain for data taken after 01mar03 using this equation. The coefficients can be found in the ascii file  data/gain.datR12 (this is provided in the AO idl distribution for correlator routines). You can also find a copy of it at AO in /home/phil/idl/data/gain.datR12.

mar03 thru feb04 : System performance of data used to compute gain curves.  (top)

Fig 1 shows the distributions on the dish of the measurements.

Fig 2 has the Gain in Kelvins/Jansky. This relies on the cals and the source flux. Ths  next plot is Tsys vs za in Kelvins followed by the SEFD  (System Equivalent Flux density) in Janskies / Tsys. At the bottom is the average beam width in arc seconds.

Fig 3 plots the coma parameter, first sidelobe height below the peak, the main beam efficiency, followed by the main beam + 1st sidelobe beam efficiency.

Fig 3 has the pointing errors in az,za, and total (added in quadrature) for the data.

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Miscellaneous section.

01jul05 dewar warms up during radar run

13oct04 1.2 hz total power ripple.

• shutter closed
• upstairs transfer switch crossed
• 260 IF used
• detect the 100 Mhz band with a  20 usecond time constant. Do this separately for polA and polB.
• Sample the data at 10 usecs.

• Top figure. This is total power versus time for polA (black) and polB (red). The polarization's are referred to the dewar (not the downstairs signal since the xfer switch was in). The data was smoothed to 10 milliseconds. You can see the jumps in polB. It is not a sine wave. The signal stays low for .55 seconds and then jumps up (about 2% Tsys) for .28 seconds. The entire duration is .83 seconds or 1.2 hz.
• Bottom Figure:  The 48 seconds of 10 usecond  sampled data was transformed and then the magnitude taken. There are a set of spikes spaced at .6 hz (with a few harmonics missing).

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