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Continuous calibration

Modified 19:44, 15 Jun 2015 by junya | Page History

    Version as of 08:06, 27 Nov 2024

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    Table with the current status of the EVN stations for the continuous calibration (band dependent)

     

    Current status of the continuous calibration implementation at the stations

     
      L Band C band M band X band K band Q band Last updated
    Ar              
    Bd              
    Ef              
    Hh              
    Jb              
    KVN - - - - No No 10-06-2015
    Mc No(work in progress) No(work in progress) No(work in progress) No(work in progress) No(work in progress) - 11-06-2015
    Mh - - - No Tested in lab No 09-06-2015
    Nt              
    On Available Available Available Available No No 15-06-2015
    Sr              
    T6              
    Tr              
    Sh              
    Sv              
    Wb in progress in progress in progress in progress     15-06-2015
    Ys - 80 Hz 80 Hz 80 Hz not tested No 5-06-2015
    Zc              

     

    • The DBBC allows to detect synchronously an 80 Hz signal integrating the power from the cal off and cal on phases.
    • The 80 Hz signal can be obtained from output "Cont Cal".
    • Continuous cal can be enabled by typing:
      • cont_cal=on (at the FS)
    • In some cases the signal is inverted and you can get negative Tsys. This is a pending issue to be solved. It can be solved by patching the FS, but this solution should be avoided in the future and look for a cleaner one. The DBBC allows to invert the signal but this does not work at V105 version yet.
    • The file of station.prc should be ready to switch between continuous calibration for some bands and traditional calibration for others. How to properly set it? See the document of /usr2/fs/misc/dbbc.txt
    • Note that your noise source should have a Tcal on the level of ~1 K rather than ~10 K. 
    • Onsala -- we have just tested the latest firmvare DDC V105 (version on 2015 Jun 10) which allows to swap the total power sampling between the Cal-On and Cal-Off registers. Now, our FS can do the proper measurements of Tsys, On-off, and Fivept at Onsala. Most likely, we will start to use it in EVN session 3/2015.