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

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

Efficiencies

• Bands 3 and 6