GMVA 4Gbps test (4.4.2019)

    Summary

    Prior to the regular fringe test of session c191 a test for recording at 4 Gbps will be executed.

    Schedule: f191a (UT 12:00 - 13:00) Rev 5 with R Cas and V1111 Oph masers

    Participating stations: VLBA, Pv, On, Ys, Mh, Ef, Noema

    Sky frequency band: 86012 - 86524 MHz  (512 MHz)

    Setup

    VLBA

    RDBE DDC mode with 4x128 MHz bands, dual-pol

    sky  start sky  stop bandwidth Sideband
    86012 86140 128 USB
    86140 86268 128 USB
    86268 86396 128 USB
    86396 86524 128 USB

    DBBC2 stations (Pv, On, Ys, Mh, Ef)

    All DBBC2 stations should use:

    • DDC mode (firmware 107 beta3)
    • 8x64 MHz bands, dual-pol.
    • IF setup: identical to standard GMVA 2Gbps mode using 2 core boards
    • Use 2nd Nyquist zone: 512 -1024 MHz
    • dbbcform=astro (Pv,On,Ef)
    • dbbcform=astro2 (Ys,Mh)

     

    bbc freq sideband bandwidth sky start sky stop
    960 USB 64 86460 86524
    LSB 64 86460 86396
    832 USB 64 86332 86396
    LSB 64 86332 86268
    704 USB 64 86204 86268
    LSB 64 86204 86140
    576 USB 64 86076 86140
    LSB 64 86076 86012

    DBBC3 stations (Pico Veleta P3)

    Pico Veleta will do simultaneous processing on the DBBC2 and DBBC3 backends.

    • DDC_V mode (firmware V124)
    • 16x32 MHz bands, dual-pol.
    • 1st LO=92100 (dictated by the DBBC2 IF requirements)
    • 2nd LO= 9048 (DBBC3 GComo)
      • Use E90LI IFs (4-9GHz LSB)
      • Baseband: 0-4 GHz USB => 83052 - 87052 sky freq
    • Bitstream order: BBC1-USB, BBC1-LSB, BBC2-USB, BBC2-LSB, ....

     

    bbc freq net sideband bandwidth sky start sky stop
    2992 LSB 32 86012 86044
    USB 32 86044 86076
    3056 LSB 32 86076 86108
    USB 32 86108 86140
    3120 LSB 32 86140 86172
    USB 32 86172 86204
    3184 LSB 32 86204 86236
    USB 32 86236 86268
    3248 LSB 32 86268 86300
    USB 32 86300 86332
    3312 LSB 32 86332 86364
    USB 32 86364 86396
    3376 LSB 32 86396 86428
    USB 32 86428 86460
    3440 LSB 32 86460 86492
    USB 32 86492 86524

    R2DBE stations (NOEMA)

    • Will use EHT mode: 1 x 2048 MHz dual-pol
    • Manual setup not based on vex-file
    • Tuning/IF selection based on the document supplied by Olivier.
    • Sideband: net LSB
      • Receiver : LSB, 1st LO synth 1910.50 MHz
      • Mixing stages: IF1 cover 4-8 GHz x 9 GHz LO2-A (LSB); filtered IF2 cover ~2-4 GHz x 4 GHz LO3 (LSB)
      • Net sideband: RX LSB * (mix LSB)^2 = net LSB
      • Sky freq 86780.0 -- 84732.0 MHz LSB
      • Sideband orientation confirmed by bandpass shape
    • Antenna #4 on pad N05 which according to M. Bremer and Dave's 2010 scripts has position
          XYZ :  4523970.486 468039.210 4460342.195
          fringes f191b with the above position
    • Alternate coordinates (2) Google maps
         N 44.634283 E 5.906658  (assumed satellite pic of pad N05, not quite sure)
         LLH2ECEF 4523912 468032 4460317 : delta 64 meters
    • Maser rate +4.52e-15 over 30 past days
    • Clock offset ~12 nanosec
    • Additional details of the NOEMA VLBI setup including local testing are on NOEMA April 2019
    • Weather
      • 03.04.2019 telescopes are stowed, snowfall and snowstorm
      • 04.04.2019 bad weather in the morning until 6am but looks much better after, good chance of observing
      • 04.04.2019 12 UT weather 3-4mm PWV variable and relatively fine so f191a observation was triggered (2013+370 only, no 3C454.3 because it fell into sun avoidance)

     

    sky  start sky stop bandwidth sideband
    85756 87804 2048 net LSB
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