Beam scans of Band 3 feed at room temperature at Green Bank

Details

Notes

  • Axes offsets on GB scanner -- take this into account when issuing position commands
    • Azimuth undershoots by 0.04 inch
    • y-axis undershoots by 0.010 inch
    • x-axis undershoots by 0.009 inch
  • Frequencies measured: 85, 90, 95, 100, 105, 110 GHz (115 not possible)
    • We adjusted the geometry to minimize the observed phase slope at 100 GHz.
  • Measured length of twists (inches)
    • 90deg #1 = 1.260
    • 90deg #2 = 1.263
    • 45deg #1 = 1.246
    • 45deg #2 = 1.258
  • Distance from transmitter horn to AUT = 70 + 3/4 inch (measured by tape measure)
  • Distance between the VNA extender waveguide flanges = 71 3/16 inch
  • Center of rotation measurements
    • H-plane setup: 3.212 inch behind horn aperture
    • E-plane setup: 1.0625 inch behind horn aperture
    • 45-deg plane setup: 2.138 inch behind horn aperture

Log for December 4

File Type 100 GHz peak / min (dB) Offsets Configuration
  H plane cross-polar -40 Y=-9.00 #2 90deg twist on Tx
  H plane co-polar -11   -
  E plane co-polar -13 X=0.00, Y=-11.15 #1 90deg on AUT, #2 90deg on source
  E plane cross-polar -38   #1 90deg on AUT
  45 degree co-polar -11 X=0.00, Y=-10.075 #1 45deg on AUT, #2 45deg on source
  45 degree cross-polar -31   #1 45deg on AUT, #2 45deg + #1 90deg on source
Note: Assembled and inserted ad hoc waveguide rotary joint using two WR-10 rectangular to circular transitions (without alignment pins) and two clamps.
45pln 7x 45 degree cross-polar -41 / -67   #1 45deg on AUT, #2 45deg + #1 90deg on source
45pln 7 45 degree co-polar -11   #1 45deg on AUT, #2 45deg on source
Hpln 10x H plane cross-polar -46 / -71   #1 90deg on source
Epln 10x,11x E plane cross-polar     #1 90deg on AUT

-- ToddHunter - 05 Dec 2008

Topic attachments
I Attachment Action Size Date Who Comment
Band_3_horn_measured_at_HIA_-_Room_100_GHz.pptppt Band_3_horn_measured_at_HIA_-_Room_100_GHz.ppt manage 1 MB 2008-12-09 - 15:45 ToddHunter ppt file from Stephane Claude
Feed007b.pptppt Feed007b.ppt manage 17 MB 2008-12-10 - 10:07 ToddHunter Sri's presentation of Band 3 scans at Green Bank to the FEIC group, modified following comments from Pavel
amplitudes.pdfpdf amplitudes.pdf manage 820 K 2008-12-07 - 23:30 ToddHunter Amplitude plots: co-polar and cross-polar overlaid
copolarPhases.pdfpdf copolarPhases.pdf manage 569 K 2008-12-07 - 23:30 ToddHunter Phase plots: co-polar
sriphotos.tartar sriphotos.tar manage 8 MB 2010-02-12 - 17:02 ToddHunter Sri's photos, extracted from the .ppt file
ssv100ghz.tartar ssv100ghz.tar manage 270 K 2008-12-07 - 21:31 ToddHunter 100 GHz ASCII data files
ssv105ghz.tartar ssv105ghz.tar manage 270 K 2008-12-07 - 21:32 ToddHunter 105 GHz ASCII data files
ssv110ghz.tartar ssv110ghz.tar manage 270 K 2008-12-07 - 21:32 ToddHunter 110 GHz ASCII data files
ssv85ghz.tartar ssv85ghz.tar manage 250 K 2008-12-07 - 21:30 ToddHunter 85 GHz ASCII data files
ssv90ghz.tartar ssv90ghz.tar manage 270 K 2008-12-07 - 21:31 ToddHunter 90 GHz ASCII data files
ssv95ghz.tartar ssv95ghz.tar manage 270 K 2008-12-07 - 21:31 ToddHunter 95 GHz ASCII data files
Topic revision: r9 - 2010-07-21, ToddHunter
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