Gain curve plots with all receivers
nov05
Gain curves for all reciever.
Gain
curves for various receivers and freq (ps) (.pdf)
are plotted versus zenith angle. (last updated 22nov05)
-
Fig 1. The plots have been averaged over any azimuth dependence. The colors
are for different receivers. For the same receiver, different frequency
measurements use different plotting symbols. The bottom of the plot contains
the color/frequency key as well as when the data for the fits was acquired.
-
Fig 2. This is the gain at za of 10 for all the gain curves using the frequencies
of the actual measurements. The solid line has averaged over azimuth, the
dashed line has taken the maximum azimuth value for each measurement (all
at a za of 10 degrees). The table at the bottom has the frequencies and
avgGain, maxGain from each gain curve. Cb, 430 and LBW max,avg values
are the same because the fits did not include an azimuth dependence.
Looking at the second figure, some of the recievers
have gains that do not follow the general trend. This could be a problem
in the cal value used. It could also be caused by and over or under illumination
of the tertiary by the horn. The cbh offset is probably coming from an
underillumation of the horn (see: hpbw
vs lambda).
The absolute gain (in K/Jy) that is quoted may be
incorrect, but the gain curves are still a valid tool for using the flux
of the calibrator sources to determine the flux of a user's source. The
only requirement is that the same cal and cal value (even if wrong in absolute
terms) is used for both measurements.
For more info on the gain curve fits and their
location see gain
curves fits at ao.
processing: x101/calmrcv/gaincurv/gaincurv_cur.pro
Old gain curves all rcvrs plotted together.
gain curve
plot all receivers made Nov03.
home_~phil