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mg002

Modified 15:52, 5 Sep 2017 by jwagner | Page History

    Version as of 08:36, 25 Nov 2024

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    MG002 Correlation Report

    General:

    • Session info: http://www3.mpifr-bonn.mpg.de/div/vlbi/globalmm/
    • Station feedback: http://www3.mpifr-bonn.mpg.de/div/vlbi/globalmm/sessions/apr17/feedback_apr17.asc
    • ALMA QA2: 2016.1.01116.V was used for polarization conversion
    • This experiment has ALMA with 32x62.5MHz, VLBA with 2x128MHz channels, and most of the EVN with a 1x512MHz channel
    • Two EVN stations (Yebes, Pico Veleta) observed in an incorrect backend mode, with a 32 MHz polyphase filterbank.
    • Due to the issue at Yebes and Pico, three correlations were performed:
      • a) standard ALMA correlation setup (58 MHz bands) discarding Yebes and Pico
      • b) narrower band correlation setup (32 MHz bands) including Yebes and Pico
      • c) mixed-band correlation with additional postprocessing of all baselines to Yebes and Pico Veleta (reconstructed 58 MHz bands)
    • The correlation output (c) appears correct, but uses a new feature that has not been vigorously tested. The data are provided without guarantees. Details are given further below.

    Fringes:

    Station Fringes Comment
    Ef yes Effelsberg DBBC2
    Eb yes Effelsberg RDBE
    On yes  
    Aa yes  
    Mh no faulty backend configuration
    Pv yes LCP bad (2bit sample dist. 78%:0:0:22%), is OK in ma008 and mb007
    Ys yes  
    Fd yes  
    La yes  
    Pt yes weak or no fringes
    Nl yes  
    La yes  
    Kp yes  
    Ov yes  
    Mk no  
    Br yes  

    Fringes plotted on all baselines to Effelserg (No0134 Effelsberg PDF), and ALMA (No0140 ALMA PDF).

    Notes:

    1. PV scan: /mnt/disks/4/7/data/ma008_PV_093-2145.vdif marked invalid by vdifuse
    2. PV: bad statistics before 092-2100 (OK after systems was restarted at Pico)
    3. PV: DBBC2 backend ran in polyphase filter bank mode, data are 16 ch x 2 pol x 32 MHz
    4. YS: DBBC2 backend ran in polyphase filter bank mode, data are 16 ch x 2 pol x 32 MHz
    5. MH: Autoccorelations look corrupted. Suspicous of 32 MHz sub-bands displayed as full band: So far no fringes, except for LCP (weak) in Scan No064. (MM-LCP.ps     MM-RCP.ps)
    6. VLBA: subintNS has to be choosen to be 640000 when adding in VLBA (and EB) having 128 MHz wide subbands. If run with the default settings an WARNING concerning "data gaps" is received and no data is being correlated.