[daip] [!16009]: AIPS - FRING FRNSRC: MIN FFT IN FREQ REQUESTED 1003040 MAX ALLOWED 262144

[Eskil Varenius]

Eskil Varenius updated #16009
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FRING FRNSRC: MIN FFT IN FREQ REQUESTED 1003040 MAX ALLOWED 262144
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           Ticket ID: 16009
                 URL: https://help.nrao.edu/staff/index.php?/Tickets/Ticket/View/16009
                Name: Eskil Varenius
       Email address: varenius at chalmers.se
             Creator: User
          Department: AIPS Data Reduction
       Staff (Owner): -- Unassigned --
                Type: Issue
              Status: Open
            Priority: Default
                 SLA: NRAO E2E
      Template group: Default
             Created: 03 April 2020 12:52 PM
             Updated: 03 April 2020 12:52 PM
           Reply due: 07 April 2020 12:52 PM (4d 0h 0m)
      Resolution due: 29 December 2022 12:00 AM (999d 11h 8m)

Dear AIPS support,
I run FRING (AIPS 31DEC19) on some S/X-band data with these parameters:
    fring.docalib = -1
    fring.calsour = ''
    fring.refant = 8
    fring.solint = 2
    fring.snver = 2
    fring.bif=7
    fring.eif=16
    fring.timeran = 0, 19, 52, 0, 0, 20, 0, 0

and it runs without complaining. However, I want to average IFs together to solve on weak sources. 
I try aparm(5)=1, but now I get
FRING2: Task FRING  (release of 31DEC19) begins
FRING2: UVGET: doing no flagging this time
FRING2: Set integration time to  1.000000 seconds, hope that is ok
FRING2: Selecting the data
FRING2: No need to divide by flux densities in this task
FRING2: Determining solutions
FRING2: Writing SN table    2
FRING2: CHKFRQ FOUND    4 INCREMENTS NOT OF THE SAME SIGN
FRING2: WILL TRY SOLUTION ANYWAY - CHECK CAREFULLY
FRING2: Time=   0/ 19 54 59, Polarization = 1
FRING2: FREQUENCIES DO NOT LIE ON A UNIFORM GRID.
FRING2: THIS MAY DEGRADE DETERMINATION OF DELAYS.
FRING2: QINIT: did a GET  of   1272252 Kwords, OFF   17465325100633
FRING2: FRNSRC: MIN FFT IN FREQ REQUESTED 1003040 MAX ALLOWED 262144
FRING2: Purports to die of UNNATURAL causes

The frequency structure of these S/X-band data may be unusual; it is
Frequency Table summary uses reference channel     0.62
FQID IF#      Freq(GHz)      BW(kHz)   Ch.Sep(kHz)  Sideband  Bandcode
   1   1       2.22599000    4000.0002    125.0000      1
       2       2.24599000    4000.0002    125.0000      1
       3       2.26599000    4000.0002    125.0000      1
       4       2.29599000    4000.0002    125.0000      1
       5       2.34599000    4000.0002    125.0000      1
       6       2.36599000    4000.0002    125.0000      1
       7       8.20899000    4000.0002    125.0000      1
       8       8.21299000    4000.0002    125.0000      1
       9       8.25299000    4000.0002    125.0000      1
      10       8.44875000    4000.0002    125.0000      1
      11       8.46415000    4000.0002    125.0000      1
      12       8.46800000    4000.0002    125.0000      1
      13       8.47185000    4000.0002    125.0000      1
      14       8.48710000    4000.0002    125.0000      1
      15       8.48725000    4000.0002    125.0000      1
      16       8.49110000    4000.0002    125.0000      1

(although I'm only intereted in the X-band part). 
Am I doing something wrong, or is this a bug? And what is meant by the lines :
FRING2: CHKFRQ FOUND    4 INCREMENTS NOT OF THE SAME SIGN
and
FRING2: FRNSRC: MIN FFT IN FREQ REQUESTED 1003040 MAX ALLOWED 262144I'm very grateful for any hints.

Kind regards (and: I hope you are all fine in these difficult times)
Eskil


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