Meteor Receiver Andrew Thoni Charlie Hunter Greg Watkins Nick Nicholson Will Marshall

2 Project 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

3 Design Objectives ObjectiveAchieved Receive 217MHz with antennasYes Demodulate input signal to the audio band. Yes Output the antenna signal to a computer for storage. Yes Playback the signal as audio.Yes

4 Illustration of Design

5 Simulated Antenna Impedance

6 Simulated Antenna Gain

7 Measured Antenna Gain

8 Simulated Antenna 3D Gain at 217 MHz

9 Measured Antenna Beam Width

10 Antenna 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.

11 Antenna 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

12 Amplifier Design

13 Amplifier 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.

14 Commercial Amplifier

15 Demodulator Circuit

16 Demodulator Amplifier Testing

17 Demodulation with MHz Input

18 PC Control and Capture Testing

19 PC 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

20 Control and Capture Problems Continued Problems –Defective buffer –Able to write to LO, but unable to generate desired frequency Solutions –Bypass buffer –External frequency source

21 PCB 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

22 Future Work Perfect Low Noise Amplifier design. Capture data with PC. Complete software package to display position and velocity of space objects.

Meteor Receiver Andrew Thoni Charlie Hunter Greg Watikins Nick Nicholson Will Marshall