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R2DBE commissioning - Dec 2016

Modified 12:45, 14 Dec 2016 by rottmann | Page History
    Table of contents
    1. 1. Clock synthesizer
    2. 2. Noise Generator
    3. 3. BDC
    4. 4. R2DBE

    Version as of 13:32, 20 May 2024

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    Clock synthesizer

    Unit was installed with the 10MHz connected from the Maser Reference Distribution box  located in the VLBI rack. The power of 10 MHz input signal was attenuated to 3.5 dBm.

    10MHzSignal.png

    The output signal was inspected on the spectrum analyzer. The line was located at exactly 2048 MHz. The level on output pin 0 was attenuated by 3dB. The resulting peak output levels were:

    Pin 0: +4.14 dBm   (to r2dbe-1)

    Pin 1: +4.00 dBm   (to r2dbe-2)

    Clock_pin0.png Clock_pin1.png
    Pin 0: Output Signal Pin 1: Output Signal

    Noise Generator

    Noise generator was installed in the rack. After powering up the front panel leds (green and orange) were not lit whereas the voltage LEDs on the front side indicated power. Dismounted and opened the unit. The power LED of the output selector box was not lit up indicating a power problem. Cable inspection showed that one of the cables powering the output selector unit was disconnected probably due to the transport.
     After replugging the cable the unit powered up nomally.

    noise_gen_nopower.png noise_gen_power.png
    output selector box indicating missing power power LED on after fixing disconnected cable

     

    BDC

    Opened the BDC to install the equalizers on the four IF outputs

    BDC_equalizers.png BDC_overview.png
    Installation of the four equliazers at the backside output IF pins of the BDC Overview of the BDC

    Installed the unit in the rack. After powering up the frontside keyboard did not react to any keys pressed. Dismounted the unit and replugged  the cable connections which could fix the problem. However after closing the lid and remounting to the rack the keypad again did not react. This procedure was repeated a number of times including using contact cleaners on the connectors. Apparently the problem only occurs after tightning the screws on the top lid. The unit has been put back to the rack with the lid screws not tightened and is currently working fine.

    The power of the 10MHz input signal has been measured to be 3.5dBm which meets the updated spes of 3dBm+-3dB as provided by Ronald.

    The 4 IF outputs of the BDC have been labeled and connected to the noise generator unit frontside panel.

    noisegen_pins.png

    TODO: confirm the IF input power levels are meeting the specs once the IFs are connected to the telescope.

    R2DBE

    Installed both R2DBE units. Connected clock to the front side pins. Connected 1PPS to the distributor box in the VLBI rack. Network cables connected to the network hub serving 192.168.178.X. Booted pv-mark6-1 and connected its second network interface with the network hub.Then started up the R2DBEs. Boot succesful with the following hostnames/IPs:

    r2dbe-1: 192.168.178.60

    r2dbe-2: 192.168.178.61

    Both R2DBEs can be reached via ssh from pv-mark6-1 (user root).

    Connected the frontside IF connectors to the noise generator frontside.