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Antenna Gain and Source calibration Jim Gibson and Jack Welch.

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Presentation on theme: "Antenna Gain and Source calibration Jim Gibson and Jack Welch."— Presentation transcript:

1 Antenna Gain and Source calibration Jim Gibson and Jack Welch

2 Antenna gain Measurement using Standard Horn Horn Gain from Shelkunoff and Frijs Horn at Edge of 6m BIMA Antenna Transfer Switches Between Feed and Horn Jupiter is the Signal Source Used BIMA 6m Antenna in Array

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10 Jupiter Flux Measured with Calibrated Antenna Temperature Scale from Ambient and LN Loads Many On/Off Measurements of Jupiter Many Tipping Curves for Extinction Tb = 145.12K +/-2K Corrected for Synchrotron Emission: Tb=143.7+/-2K

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17 Calibrating ALMA Images Calibrate Planets as often as Necessary Transfer Planetary Fluxes to Phase Calibrators. Use 2 or 3. Accurate Extinction Needed Here Scale ALMA Images to the Phase Calibrator Images. Little Extinction Correction Needed

18 Future Plans Transfer 28.5 Jovian Flux to Mars and MWC349 Repeat the Calibration at 90 GHz with Mars/Venus Generate Overall Scale for MWC349 Test the Accuracy of Tipping Curves Test Stephane’s Idea at 90 GHz

19 Tipping Experiments Compare with an Interferometric Extinction Curve on a Stable Day Compare with Model Atmospheric Calculations Try it with the Standard Gain Horn; It’s Pattern is Cleaner and can be Calculated

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