[daip] a problem regarding APCAL

[Rusen Lu]

Dear Professor,
I am now processing a CMVA dataset observed at 2000. And there are 4
participating antennas (3 VLBA antennas: Pie Town; Fort Davis; Los
Alamos, and, KittPeak Telescope (12 m, Kitt Peak, Arizona) ). It
happened to me a problem when I did the amplitude calibration using
APCAL.

Let me describe it specifically:

I have the system temperature (Tsys) and gain curve info of the four
antennas, besides this, I also have the antenna temperature (Tant) and
the ratio of source/system (Ta/Tsys) for KITTPEAK. So, I want to verify
the agreement of amplitude calibration for KITTPEAK in two different
ways. One is using the Tsys, and the other one is using Tant and
Ta/Tsys. 

Firstly, I generate TY table (using Tsys in the external file) and GC
table using ANTAB . Then I use the Tant and Ta/Tsys (using SRC/SYS
parameter) info to get another TY table and GC table. After this ,
I use APCAL to get two SN tables and, then CL tables, both without
correction for atmospheric opacity. But the gain is different for KITT
PEAK!

So, could you please give me some explanation? 
Thanks in advance!


Rusen Lu