Band 3 beam scans (March 2010)

Initial setup: March 2, 2010

  • The serial number of the band 3 cold cartridge is SN-08. Here is its PAI report.
  • Adjusted source LO power by setting AMC gate voltage to -1.0V which caused the AMC E drain to be ~0.9V (Note: there is still a control channel flip in software somewhere.)
  • Adjustment of warm optics mirrors was done at elev=0 deg until we hit the motion limit: trying to go upward (away from cryostat axis) and inward (toward cryostat axis).
  • Results in table below derived from Todd's C program to fit a flat-topped Gaussian:
    • flatgauss -f verticalcutf.txt -s 74 -x 0
    • flatgauss -f horizontalcutf.txt -s 74 -y 0

Channel Fitted Peak in X (deg) Fitted Peak in Y (deg) Nominal X (deg) Nominal Y (deg) Error in X (deg) Error in Y (deg) FWHM in X (deg) FWHM in Y (deg)
Pol 0 +0.2593 +1.8957 +0.3109 +1.7345 -0.0516 +0.1612 4.139 4.769

March 3, 2010

  • Source power setting: Set Vgate=-1.65, yields AME_E =+0.60
  • Discovered copol sidelobes at 0.050m from boresight. Is only 5dB down from peak at tilt table = 45deg. Not seen at table = 0 deg. Tracked down to gap in the TKRAM coverage. Added another block of TKRAM to cover the gap. Sidelobe gone.
  • Failure to lock source. photomixer current needs to be -0.3 to be healthy, but it is only -0.11 mA. Fiber cable problem. Morgan fixed. Now getting -0.62mA. The receiver IFpower is 3.5.
  • Told Greg about a mechanical fix to hold the fiber cable metal shell securely to avoid cable flexure from moving the connector.
  • Scan parameters: 121x121 over span of 0.175x0.175m
    • 11:40AM started first scan


-- ToddHunter - 2010-03-02
Topic attachments
ISorted ascending Attachment Action Size Date Who Comment
horizontalcutf.pngpng horizontalcutf.png manage 42 K 2010-03-02 - 15:26 ToddHunter X cut
nowarmoptics.pngpng nowarmoptics.png manage 246 K 2010-03-09 - 14:43 ToddHunter scans taken without warm optics
verticalcutf.pngpng verticalcutf.png manage 43 K 2010-03-02 - 15:28 ToddHunter Y cut
Topic revision: r3 - 2010-03-09, ToddHunter
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