1. W2UC: Union College RF Repeater for Amateur Use
Union College, Schenectady, NY
Department of Electrical Engineering
Senior Project Detailed Design Presentation
Robin Stevenson
Project Advisor: Prof. James Hedrick

2. Project Goals
Design and construct an RF repeater to extend the range of mobile radios in the area surrounding the campus
Provide a platform for future student projects involving RF technology

3. What is a Repeater?
Relays transmitted signal from one location to another
Extends the range of weak transmitters
Can be used to communicate over geographic boundaries
Used by:
-HAM (Amateur) Radio Operators
-Emergency Services Personnel
-Commercial Interests (Trucking)

4. Repeater Block Diagram
Duplexer
Controller
Antenna (Transmits and Receives)
Receiver
Transmitter
Power Supply
Control Line
Power Line
Signal
MHz
MHz
Transmit only when there is a signal being received

5. Design Considerations
Off the shelf components vs. designed
Location
Meet FCC Regulations
Stability
Transmission power
Station identification
Interference

6. Requirements Specifications Measurement Devices Output Power – 10W
Receiver Sensitivity – 0.1µV at 20dV SINAD
Antenna Radiation Pattern
Antenna VSWR less than 1.5:1
Duplexer isolation
FM Transmit Deviation
Spurious and Harmonic Signals
Measurement Devices
Wattmeter
Calibrated signal generator
SINAD meter
Field Strength Meter
Deviation Meter
Spectrum Analyzer

7. Materials Sourcing
Power Supply, microcontroller, crystals will be ordered off-the-shelf using IEF Grant
Antenna was constructed as part of another student’s summer research
Receiver, transmitter, duplexer have been acquired from railroad surplus

8. Project Timeline Fall Term Winter Term Incorporate duplexer, antenna
Develop block diagram
Incorporate controls
Get Rx, Tx operational
Obtain license
Choose freqs, submit for coordination
Take performance data
Finish Design Document
Make necessary modifications to Rx, Tx
Begin taking initial data
Write paper sections

9. Any Questions?