C251Z

General information

• A100 GHz test, PI DW Kim, scheduled for Nn Pv On Ax
• Session info: http://www3.mpifr-bonn.mpg.de/div/vlbi/globalmm/
• Session feedback: https://www3.mpifr-bonn.mpg.de/div/vlbi/globalmm/sessions/apr25/feedback_apr25.asc
• ANTAB and log files: ?
• Station feedback:
  • APEX just the lasts two 104 GHz scans are ok (IF issues before them), while at 114 GHz all scans were ok
  • NOEMA reports all was ok, but the 114 GHz scans produce no fringes
• Entire track is project 100GTEST with observations at 104 GHz in the first half and 114 GHz in the second half
• Polarizations are somewhat off from circular; Onsala at 114 GHz had a QWP designed for 86 GHz, NOEMA perhaps similarly a 86 GHz QWP, whereas APEX and Pico observed in linear polarization without a QWP

Status

Fringes

Notes

APEX turned out to have different 1st LO offsets at the two different sky frequencies. The DiFX v2d settings are:

# APEX 104 GHz
loOffsets = +21.536, +21.536, +21.536, +21.536, +21.536, +21.536, +21.536, +21.536,
            +21.536, +21.536, +21.536, +21.536, +21.536, +21.536, +21.536, +21.536
# APEX 114 GHz
loOffsets = -8.262, -8.262, -8.262, -8.262, -8.262, -8.262, -8.262, -8.262,
            -8.262, -8.262, -8.262, -8.262, -8.262, -8.262, -8.262, -8.262

The NOEMA tunings are provided in their spreadsheet for NOEMA 104 GHz and NOEMA 114 GHz.

There are fringes for NOEMA at 104 GHz using the provided tunings. The 114 GHz part of the track, however, has no NOEMA fringes with the definitions as in the spreadsheet, nor with alternate approaches tried e.g. net sideband of the definitions flipped,channel order reversed (both with and without flipping the net sideband), very wide residual rate space (0.100s AP instead of 1.024s AP) and wide 2048-channel (+-16 usec) residual delay space. According to the spreadsheets, the 104G data and afterwards the 114G data originated from different PolyFix units, but the data were routed to the same Mark6 recorder3. Merely the cplane input_stream definitions were updated as necessary during the switch from 104 to 114 GHz. The lack of NOEMA 114 GHz fringes remains unexplained.

No polconversion was performed.

Pico and APEX linear polarizations, and Onsala elliptical(?) polarizations, were merely re-labeled as "RCP'/"LCP", but physically remain linear.

Post-Correlation checks

                                      ON PV NN AX BX
c251z104G_1000 No0001    3C273 104ghz o  o  o  o
c251z104G_1001 No0002    3C273 104ghz o  o  o  o
c251z104G_1002 No0003    3C273 104ghz o  o  o  o
c251z104G_1003 No0004    3C273 104ghz o  o  o  o
c251z104G_1004 No0005    3C273 104ghz o  o  o  o
c251z104G_1005 No0006    3C273 104ghz o  o  o  o
c251z104G_1006 No0007 1308+326 104ghz o  o  o  o
c251z104G_1007 No0008 1308+326 104ghz o  o  o  o
c251z104G_1008 No0009 1308+326 104ghz o  o  o  o
c251z104G_1009 No0010 1308+326 104ghz o  o  o  86
c251z104G_1010 No0011 1308+326 104ghz o  o  o  o
c251z104G_1011 No0012 1308+326 104ghz o  o  o  o

                                      ON PV NN AX BX
c251z114G_1012 No0013 1308+326 114ghz o  o  o     o
c251z114G_1013 No0014 1308+326 114ghz o  o  o     o
c251z114G_1014 No0015 1308+326 114ghz o  o  o     o
c251z114G_1015 No0016 1308+326 114ghz o  o  o     o
c251z114G_1016 No0017 1308+326 114ghz o  o  o     o
c251z114G_1017 No0018 1308+326 114ghz o  o  o     o
c251z114G_1018 No0019 1741-038 114ghz o  o  o     o
c251z114G_1019 No0020 1741-038 114ghz o  o  o     o
c251z114G_1020 No0021 1741-038 114ghz o  o  o     o
c251z114G_1021 No0022 1741-038 114ghz o  o  o     o
c251z114G_1022 No0023 1741-038 114ghz o  o  o     o
c251z114G_1023 No0024 1741-038 114ghz o  o  o     o