Both the L-Narrow and L-wide receivers are sharing a gain curve obtained from data taken with the L-wide receiver on August 12-15, 2001 using the "spider scan" routine. A low frequency set of data was taken (1175,1300,1375,1415 MHz) and a high frequency set (1415,1550,1610,1666 MHz). The data results are for the average of the two polarizations (Stokes I/2). The southwest quadrant of the reflector had not yet had it's final adjustment when the August data was taken. The surface rms went from 5.5 mm rms (before) to < 1.8 mm after the final adjustment. So the August data had 3/4 of the dish with an rms < 1.8 mm and 1/4 of the dish with an rms of about 5.5 mm. In September, 2001 the southwest quadrant adjustments were finished and a few sources were remeasured.

Further information, plots of the fits, etc. can be obtained here

The fit is for 1415 MHz, and is in K/Jy. The zenith angle (za) and azimuth (az) are in degrees and the (za-14) terms are only used for za > 14 degrees.

Average Gain [(polA+polB)/2]:

gainavg(az,za,f=1415MHz) = 10.999 - 0.10291*za + 0.0134357*(za-14)² - 0.0071745*(za-14)³ - 5.2154x10^-08*cos(az) - 1.3225x10^-07*sin(az) + 1.1642x10^-08*cos(2*az) - 7.3761^-07*sin(2*az) - 0.20990*cos(3*az) - 0.098026*sin(3*az)

gainavg(az,za,f=1175MHz) = 11.378 - 0.081304*za - 0.026763*(za-14)² - 0.0026350*(za-14)³ + 1.0319x10^-06*cos(az) - 3.1292x10^-07*sin(az) - 7.5973x10^-07*cos(2*az) - 1.9372x10^-07*sin(2*az) - 0.17180*cos(3*az) - 0.046071*sin(3*az)

gainavg(az,za,f=1300MHz) = 11.265 - 0.095145*za + 0.004248*(za-14)² - 0.0066783*(za-14)³ + 7.2271x10^-07*cos(az) + 9.0897x10^-07*sin(az) + 4.3958x10^-07*cos(2*az) - 8.1956x10^-07*sin(2*az) - 0.22135*cos(3*az) - 0.074295*sin(3*az)

gainavg(az,za,f=1375MHz) = 11.114 - 0.10412*za + 0.023915*(za-14)² - 0.0094938*(za-14)³ - 8.3447x10^-07*cos(az) + 1.0729x10^-06*sin(az) - 4.5402x10^-08*cos(2*az) - 1.3411x10^-07*sin(2*az) - 0.22827*cos(3*az) - 0.080216*sin(3*az)

gainavg(az,za,f=1550MHz) = 10.786 - 0.10748*za + 0.019265*(za-14)² - 0.0075530(za-14)³ - 7.8976x10^-07*cos(az) - 6.5565x10^-07*sin(az) - 7.4506x10^-08*cos(2*az) - 4.1723x10^-07*sin(2*az) - 0.20972*cos(3*az) - 0.14330*sin(3*az)

• Gain versus Azimuth and Zenith angle. The length of the arrow is proportional to the gain (1 tick mark = 5 K/Jy). The angle of the arrow also measures the gain: vertical up is the maximum value, 90 degrees to the right is 25% of the maximum, and vertical down is 50% of the maximum value. Sources with declination < 18 deg (AO latitude) will appear on the upper half (northern part) of the dish. Sources with declination < 18 deg will appear on the lower (southern half) of the dish. Rising sources are on the left (west half of the dish) and set on the right (east half of the dish). The southwest quadrant is in the lower left. A number of tracks across the dish have double arrows. These correspond to the lower and upper frequency data sets (that were taken on different days). How close these two sets overlap shows the repeatability of the measurements. The table at the bottom shows the average over the entire dish (9.51K/Jy) and the averages in 5 deg za steps.
  

• Fit Residuals versus Azimuth and Zenith Angle. One tick mark is 0.5 K/Jy. The arrow direction is: up goes to no difference; Right (90deg) means (data-fit) = 1K/Jy; Left (90deg) means (data-fit) =-1K/Jy. The black 2 arrows in the upper left (source B0139+029) point to the right so they are 1K/Jy above the fit. The flux for this source is probably a little high.
  

  
  

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  Last updated: Friday, 31-May-2002 14:08:59 AST