Continuous calibration

    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 Available Available Available Available Available Available 18-06-2015
    Hh Available Not yet Not yet Not yet Not yet N/A 04-05-2020
    Jb 80 Hz 80 Hz 80 Hz - 80 Hz - 04-04-2019
    KVN - - - - No No 10-06-2015
    Mc Available Available Available Available Available - 2-04-2019
    Mh - - - No Available No 10-04-2019
    Nt Available Available Available Available Available Available 05-05-2020
    On Available Available Available  Available No No 11-07-2018
    Ro Available 10Hz N/A N/A Available 10Hz Not yet Not yet 3-10-2017
    Sr Available   Available   Available   22-01-2021
                   
    T6 Available Available Available Available Available Not yet 6-5-2021
    Tr Available Available Available   Available   6-03.2019
    Sh              
    Sv              
    Ur              
    Wb not going to implement on current Receiver because too much effort  not going to implement on current Receiver because too much effort  not going to implement on current Receiver because too much effort  not going to implement on current Receiver because too much effort      29-01-2019
    Ys - 80 Hz 80 Hz 80 Hz not tested No 5-06-2015
    Zc              
    Ir Not yet   Not yet Not yet Not yet N/A N/A 6-11-2019

     

    • 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. The system is functional now. We have switched it on during N15L3. We are going to reduce Tcal from ~10 K to ~1 K and then start to use it in the user experiments at L and C bands in session 1/2016. The X-band 80Hz calibration hardware is also ready now and will be installed when the manpower is available. 
    • Hart -- we are working on implementing this on our 15m first as a test bed to see how well our solution will work.  At the moment we are still waitin gon components for that.
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    Robledo -- 10Hz continuous calibration for L, S and X bands already available. Work in progress to provide antabfs and rxg files. Currently continuous calibration not possible for K and Q bands, only on/off.
    Posted 12:04, 9 Feb 2016
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    Changes: - Columns sorted by frequency and polarization. - Check ifdXX for proper configuration.
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