[daip] [!7226]: AIPS - strange scaling of visibility amps & weights w/ DOBAND=1

[Michael Bietenholz]

Michael Bietenholz updated #7226
--------------------------------

strange scaling of visibility amps & weights w/ DOBAND=1
--------------------------------------------------------

           Ticket ID: 7226
                 URL: https://help.nrao.edu/staff/index.php?/Tickets/Ticket/View/7226
           Full Name: Michael Bietenholz
               Email: mbieten at yorku.ca
             Creator: User
          Department: AIPS Data Reduction
       Staff (Owner): Eric Greisen
                Type: Issue
              Status: Open
            Priority: Default
                 SLA: NRAO E2E
      Template Group: Default
             Created: 08 September 2015 05:34 PM
             Updated: 01 October 2015 03:45 PM
      Resolution Due: 24 September 2015 04:59 PM 



I just ran a MNJ ( 64-bit binary Linux distrib), and I still get the strange weight scaling upon DOBAND=1.

Here's the exact numbers I get from the test_gb076.fits file I sent earlier:

UVPRT;  BIF 5; EIF 5; CHANNEL 16; ANTENN 3,10 0;  STOKE 'RR'; DPARM(1) = -1; DPARM(10) adjusted as necessary.  I'm just looking at the first value that prints out: ANT 1-3; time 1/00:00:00.5; 

I get this: 

DOCALI -1; DOBAND  -1:   amp = 647.6 uJy; (phase=177);  wt = 1.0000
DOCALI +1; DOBAND  -1;  amp = 38.63 mJy; (phase=162 );  wt = 2.869e-4

So far its (almost) good -  the amplitude increases by 59.65x, so the weight should
decrease by 59.65**2 or 2.810e-4.  Its pretty close - not sure why its not exact?

Now turn on DOBAND - 

DOCALI +1; DOBAND +1;  amp = 35.97 mJy; (phase=164 ); wt =  3.775e-5

So the amplitude decreases by a factor of 0.93, suggesting that the weights
should *increase* by about 14%, but instead the weights *decrease* by ~8x.
This is near the center of the band and the BP corrections are <10%.

DO you get different numbers?




------------------------------------------------------
Staff CP:  https://help.nrao.edu/staff