[daip] 512 Mbps IF setup and AIPS

[Yuri Y. Kovalev]

Dear colleagues,

We observe in BL149 these days with the following frequency setup:

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
! U band
! Central frequency for SEFD 15369 MHz
!
setinit = 'BL149-512-2cmv.set' /
! NON STANDARD setup created by Yuri Kovalev on 08/27/2008
!
! based on Standard setup file: v2cm-512-16-2.set                       
!     (Produced by MAKESETUP)
!      For the the 2 cm band.
!        Radio Astronomy allocation:  15350-15400
!        Radio Astronomy footnote(?): 14470-14500
!
!        There are 4 filters in the VLBA IF converter.  They are
!        11820-12980, 12820-13980, 13820-14980, and 14770-15630 GHz.
!        The filter is chosen based on the frequency of the first channel
!        assuming an upper sideband first mix.  The splits are at 12.9,
!        13.9 and 14.9 Ghz.
!
!        VLA band 14650 - 15325 MHz for 0.9 sensitivity
!        Methanol has a rest frequency of 12178.595 MHz
!
!     Format      Tape length  Density  Tape speed  Time/pass
! VLBA/MkIII/MkIV    17600      High     160.00        22:00
!    MkIII/MkIV       8800      Low      270.00         6:31
!      512 Mbps - 1 pass/headpos - 2 tapes (VLBA) or 2 heads (Mark IV)
  nchan    = 16
  bits     = 2
  bbfilter = 8.0
  freqref  =  15360.99
  freqoff  =  -27.50, -27.50, -27.50, -27.50, -11.50, -11.50, -11.50, -11.50,
               4.50,  4.50,  4.50,  4.50,  20.50,  20.50,  20.50,  20.50
  netside  =  L, L, U, U, L, L, U, U, L, L, U, U, L, L, U, U
  pol      = dual
  /
endset  /
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

I noted recently that AIPS (31DEC08) VLBASUM shows the following for 
such a dataset:

Frequency Table summary
FQID IF#      Freq(GHz)      BW(kHz)   Ch.Sep(kHz)  Sideband
   1   1      15.32555250    8000.0005    500.0000      1
       2      15.33349000    8000.0005    500.0000      1
       3      15.34155250    8000.0005    500.0000      1
       4      15.34949000    8000.0005    500.0000      1
       5      15.35755250    8000.0005    500.0000      1
       6      15.36549000    8000.0005    500.0000      1
       7      15.37355250    8000.0005    500.0000      1
       8      15.38149000    8000.0005    500.0000      1

I would expect that different IFs would have dufferent Sideband
(1 and 2?) since we observe in both, U & L.
Could you please comment on this?

Thanks,
Yuri