Alfa cal values measured in lab (apr04)


    The alfa high cal was measured in the lab in apr04. The noise figure analyzer was used stepping the frequency by 10 Mhz for each measurement. A warm omt was used to couple the NFA signal into the receivers omt (the horn was not installed). The measured data was fit with a 3rd order polynomial over the range 1230 to 1520 Mhz.  The data is plotted in black with the fits in red. Dashed green lines mark the boundary of the alfa band (1220 to 1520). The plots show:
      There is a high frequency structure in some of the measured cals with a period of about 50 Mhz. This would be 3 meters in air. The Tsys/Tcal ratio also has frequency structure at the 25Mhz level. Both of these measurements were made with "temporary setups". We should try remeasuring the cal values using sky and absorber and the alfa if/lo chassis. For now the cal values will be those of the 3rd order fit
processing: rcvm/Misc/alfaapr04/,x101/040422/