Meteor ReceiverMeteor Receiver

Andrew ThoniCharlie HunterGreg Watkins

Nick NicholsonWill Marshall

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Project OverviewProject Overview

• Design a receiver to detect objects in orbit passing through the NAVSPASUR.

• There is a community of hobbyist who want to detect space objects.

• Dr. Smith is extremely interested in owning one of these systems for a personal hobby.

• Total cost estimate is $360

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Design ObjectivesDesign Objectives

Objective Achieved

Receive 217MHz with antennas Yes

Demodulate input signal to the audio band.

Yes

Output the antenna signal to a computer for storage.

Yes

Playback the signal as audio. Yes

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Illustration of DesignIllustration of Design

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Simulated Antenna ImpedanceSimulated Antenna Impedance

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Simulated Antenna GainSimulated Antenna Gain

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Measured Antenna GainMeasured Antenna Gain

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Simulated Antenna 3D Gain at 217 MHzSimulated Antenna 3D Gain at 217 MHz

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Measured Antenna Beam WidthMeasured Antenna Beam Width

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Antenna ProblemsAntenna Problems

• Antenna design is 75 Ω but the testing equipment is 50 Ω

• Mechanical solution for attaching a connector

• Optimal spacing between the two dipole sides

• Directivity is too low.

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Antenna SolutionsAntenna Solutions

• BNC 75 Ω to 50 Ω transformer to connect to the network analyzer

• Spade lugs and hose clamps to connect the cable to the driven element

• Dipole spacing was not an issue• Redesign and add matching network to

increase directivity

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Amplifier DesignAmplifier Design

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Amplifier Problems and SolutionAmplifier Problems and Solution

• Problems– Capacitors were too short for gaps in the

board.– Soldering was not done well.– All the boards were shorted out.

• Solution– Use commercial amplifiers.

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Commercial AmplifierCommercial Amplifier

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Demodulator CircuitDemodulator Circuit

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Demodulator Amplifier TestingDemodulator Amplifier Testing

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Demodulation with 217.02 MHz InputDemodulation with 217.02 MHz Input

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PC Control and Capture TestingPC Control and Capture Testing

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PC Control and Capture ProblemsPC Control and Capture Problems

• Problems– Two ports are XLR connectors– Unable to consistently write to DAC

• Solutions– Proposed XLR to RCA adapter– DAC defaults to maximum gain

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Control and Capture Problems ContinuedControl and Capture Problems Continued

• Problems– Defective buffer– Able to write to LO, but unable to generate

desired frequency• Solutions

– Bypass buffer– External frequency source

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PCB ProblemsPCB Problems

• Coax input through-hole pads too small• DB-25 connector does not fit• Voltage regulator pins reversed• Buffer chip enables tied to disabled position• RCA outputs blocked by other components• Option for external oscillator not included

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Future WorkFuture Work

• Perfect Low Noise Amplifier design.• Capture data with PC.• Complete software package to display

position and velocity of space objects.

Meteor ReceiverMeteor Receiver

Andrew ThoniCharlie HunterGreg WatikinsNick NicholsonWill Marshall