08 July 2000 - Gain Curve Calibration Q Band Status Steven T. Myers 12 September 2000 ------------------------------------------------------------------------------- Previous Gain Curves - April 15/16, 1999 ELINT Data For AN 3,4,8,11,12,13,14,16,20,22,25,27 (tau=0.06) Elevations 28 to 82 degrees Antenna 6 dead. ------------------------------------------------------------------------------- Current Data: Summary of Run - Q Band tau=0.09 from tipper data data quality fair to good 20 antennas available, AN 11 out of array Poor data on AN 10,21,24,28 Unusable data on AN 17,20 AN 3 good AN 4 fair AN 6 good AN 8 good note: gain variation only 9% EL=25 to 72 AN 10 poor - insufficient EL range, need EL<34 data AN 11 missing from array - USE APR99 CURVE INTERIM AN 12 good note: gain variation only 9% EL=25 to 72 AN 13 good note: curve max at EL=65 AN 14 fair - only single low EL scan at EL=15 AN 16 good note: gain variation only 7% EL=20 to 72 AN 17 bad data (low gains) - deleted ==> NO USEABLE CURVE AVAILABLE AN 18 fair - need EL>72 data note: curve max at EL>72 AN 19 fair - noisy data AN 20 bad data (low gains) - deleted ==> USE APR99 CURVE INTERIM AN 21 poor - insufficient EL range, need EL<32 and EL>72 data note: curve max at EL>72? AN 22 good AN 24 poor - need better data at EL<25, EL>60, noisy, raw gains low note: curve max at EL=35 AN 25 fair - noisy, no data for EL<28 so beware! AN 26 fair - need better data at EL>60 AN 27 fair - noisy data EL<35 AN 28 poor - noisy data note: curve max at EL=62 ------------------------------------------------------------------------------- Results can be found at http://www.aoc.nrao.edu/~smyers/calibration/Gains/ Contents: Q-Apr99.elint ELINT output final Q band from April 1999 Q-Jul00.elint ELINT output final Q band from July 2000 Q-Jul00.elint.run1.ps.gz plots for minimally edited data Q-Jul00.elint.ps.gz plots for final edited data ABSQGAIN-JUL00.001 Jul00: CLCOR Procedure, absolute calibration FIXQGAIN-JUL00.001 Jul00: CLCOR Procedure, gain normalized FIXQGAIN-APR99.001 Apr99: CLCOR Procedure, gain normalized FIXQGAIN.001 AIPS procedure to run CLCOR, best data Q-08Jul00.status this file gainextract.pl perl script to extract curves from ELINT out gainplot.sm sm macro to plot gain curves The useful file FIXQGAIN.001 as well as the plot Q-Jul00.elint.ps.gz are linked to the calibration page http://www.aoc.nrao.edu/~smyers/calibration/index.html and the gain curve page http://www.aoc.nrao.edu/~smyers/calibration/Gains/index.html ------------------------------------------------------------------------------- Suggestions for Next Calibration Run: We are still missing (at this time) useable curves for AN 17, and should get new curves for AN 11 and 20. We have only poor data for AN 10,21,24,28. Furthermore, this run did not go to high enough elevation, and some of the antennas did not have data at low elevations (they were out of the array then). I suggest that we conduct another full gain curve run in the early winter - late November or early December - when the weather improves. Although the array will be in A configuration, the improved weather should offset any problems this will cause. In addition, we would have data for any new receivers added in the fall. Note that getting reliable gain curves is sufficiently important for observers at Q and K bands that it is worthwhile to devote suffient time to track the calibrator through the full elevation range (as well as possibly going "over the top"). Also, I would plan to include U band in the schedule to make sure we have updated gains there also. It would be good to not schedule this shoe-horned on a maintenance day as this often means that some antennas are missing (especially from the beginning of the run). This was a problem this time around in particular. -Steven Myers -------------------------------------------------------------------------------