A Radio Telescope for High School Education

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A Radio Telescopefor High School Education

• Abe Reddy
• North Dakota State University, Department of
  Physics
• Advisor Professor Brian Keating, UCSD CASS
• UCSD Physics REU, Sponsored by NSF

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Outline

• Radio Astronomy and Radio Telescopes
• SRT Design
• SRT Capabilities

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Radio Astronomy

• Radio vs. Optical
• Less 1mm to several meters/400-700nm

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Radio Telescopes

• Larger than optical
• Angular resolution proportional to ?/D
• Prime Focus vs. Cassegrain Reflectors
• Reflector, Subreflector, feed/horn, receiver

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Overview

• Made From Commercially Available Parts
• Capable of receiving signals at 3 12 GHz,
  simultaneously
• Freeware Software Interface written in Java

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Antenna
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Antenna Mount

• Motors for Azimuth and Elevation angles
• 0.1 degree pointing resolution
• Reed Sensor
• 12 pole magnet
• 11.7 counts/degree
• Counts are sent to Controller Box

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Receiver Design

• Orthomode Transducer
• Splits EM waves into orthogonal components
• Low Noise Block Downconverters
• High Electron Mobility Transistor Amplifier
• Increases the signal amplitude

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• Mixer
• HEMT output and reference signal
• Heterodyne downconversion to reduce frequency
• IF Amplifier
• Amplifies signal again
• Passes signal through shielded coax cable
• Bias-T Circuit
• Removes AC signal component

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• Passed through total power detector then
  amplified again
• Low-Pass Filter
• Removes High-Frequency Interference
• Voltage to Frequency Converter
• Converts Voltage to pulses
• Stamp Microcontroller
• Determines frequency of pulses
• Communicates with computer

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Software Interface

• Displays map of the sky
• Displays power output for all 4 channels
• Graphs power vs. time
• Outputs contour plot for 25 point scans

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Data Analysis

• Azimuth Scans
• Equivalent Blackbody Temp
• Polarization

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Outlook

• Usage as a Polarimeter
• Data Analysis
• Pointing Corrections
• Lab Courses