Electrical Engineering: Radio Frequency Detector Project Report

This report details the development of a low-cost radio frequency (RF) detector designed for emergency services. The project aimed to create a cost-effective and user-friendly system using the Automatic Position Reporting System (APRS) with a pseudo-Doppler direction-finding method. The student's responsibilities included planning, designing, and implementing the prototype, focusing on a budget of $500. The project involved the use of an antenna switcher, VHF magmount antenna, Arduino microcontroller, and other components. The report covers the theoretical background, engineering knowledge applied, challenges faced (such as control signal interference), and solutions implemented (like the use of an Arduino UNO). The student successfully developed a lightweight and accurate radio signal detection system, with testing conducted using amateur radio repeaters. The project demonstrated the feasibility of creating a low-cost RF detector with practical applications.

Competency Demonstration Report (CDR)
Career Episode 1

CE 1.1: Project Introduction
Name of the Project : Developing Low Cost Design of Receiver for Radio
Detection
Geographical Location : [Please Fill]
Project Duration : [Please Fill]
Organization : [Please Fill]
Position in the Project : Team Member
CE 1.2: Project Background
CE 1.2.1: Characteristics of the Project
The technology for RFD (Radio Detection Finding) is widely used as emergency services
by various rescue team and search parties. The application of the RDF helps in locating the
disaster victims, and emergency personnel with the use of the radio signals. The RFD available
in the markets are not widely used in the search parties due to high cost and complexity in use. In
addition to that, I have found that available radio detection system are highly complicated and
expensive and requires extensive training for the users. Therefore, in this project I have worked
for developing a low cost and complex RDF system for regular usage. I have studies and
evaluated various technologies that are low cost and can be replaced with existing technologies
for providing low cost equipments. In this project, I have focused on implementing the criteria
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and technology for APRS (Automatic Position Reporting System) for integrating the telemetry,
messaging and positioning techniques.
CE 1.2.2: Objectives developed for project
In this project, I have made my significant aim to provide an easy deployable and low
cost radio direction detection system that can be commercially used in wide range. The
developed system would allow the firefighters and other rescue teams to easily search for the
persons in real time with greater efficiency. In addition to that, in order to effectively manage
and complete the system design within allocated time, I have formulated the below mentioned
objectives:
 To evaluate the working principle for radio frequency detection system;
 To propose an easy to implement and low cost architecture for radio frequency
detection receiver;
 To develop the appropriate receiver using pseudo-doppler;
 To conduct the operational and functionality testing for the developed prototype
model;
 To validate the transmitter characterization and the power supply to the developed
prototype;
CE 1.2.3: My area of work
For the implementation of the prototype model for radio frequency detector, I have
worked with the theoretical experience as telecom engineer. Before staring the hardware
implementation and defining the specification for the prototype model, I have studies the existing
technologies that are being used in the RFID applications. Based on the identified functionality
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and operations, I have selected Automatic Position Reporting System with DF method for
maximum compatibility with the network. I have further studied and selected the application of
“Pseudo Doppler direction finding operation theory” for determining the accurate angle of arrival
for the signal. Apart from that, I have developed the appropriate bock diagram showing the
connectivity between the different hardware elements used in the proposed system.
Figure 1: Block diagram for the proposed Radio Frequency detector
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CE 1.2.4: Project Group
Figure 2: Team Member associated in this project
CE 1.2.5: My responsibilities throughout the project
I have taken multi-facet responsibility for the planning, design and prototype
implementation of the radio detection system. I have studied various journals and articles for
identifying appropriate and low cost technology for developing the prototype model. In addition
to that, I have focused on developing the proposed system within $500/unit cost. Therefore, I
have selected antenna switcher component, VHF magmount antenna, friendcom, arduino
Microcontroller, Whip Antenna and argent data tracking system for designing the appropriate
radio detection system.
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CE 1.3: Distinctive Activity
CE 1.3.1: Comprehending the Theory of the project
In order to implement the proposed radio frequency detection system, I have proposed the
application of 4 element array antenna for the integration of the pseudo-Doppler system. Ii have
used antenna switcher for electronically driving the rotating elements of the antenna. I have
further used the outputted RF signals for routing towards the FM receiver for demodulating and
processing the signal through the connected circuit. In the signal processing module, I have made
the control signals synchronized with the antenna for receiving the FM signal and detecting the
direction of the signal. In addition to that, I have connected and proposed the network for
transmitting back the signal metrics to the centralized receiver for processing the data.
CE 1.3.2: Engineering Knowledge and Skills applied in the project
In this project, I have used copper clad circuit board for developing the required board for
antenna switching. I have further utilized my knowledge and understanding of Dremel tool for
accurately cutting the circuit around the edges. During the circuit design of the switching board, I
have designed four island shaped area for taking the input for the antenna. I have further used the
switching diodes for controlling the switching of the antenna input. Moreover, I have used an
additional connector for feeding the RF output to the required FM receiver. I have therefore
characterized the antenna between the frequency range of 10MHz-3GHz.
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Figure 3: Design of the antenna circuit
CE 1.3.3: Accomplishment and Task Performed
In the proposed circuitry of the antenna, I have used switching control lines and COTS
magmounts for completing the design. I have used multicolor control cable for the antenna while
connected them with the biasing the island components. I have further used small SMA Cable for
output port of the FM receiver. In the completed design of the antenna, I have used diodes for
performing the physical transformation from the analog switching to electrical switching.
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Figure 4: Completed Circuit for the Radio Detection System
CE 1.3.4: Identified Issues and Their Solutions
Issue: After developing the prototype model for the antenna and radio frequency
detection I have worked for conducting the operational testing for the antenna switching control.
During the testing phase, I have observed that the control signals impacted the performance of
switching antenna while softening the control signal. This has created significant issue in the
proposed and expected outcome for the radio frequency detection system.
Solution: For eliminating the functional issue I have replaced the existing control circuit
with the ATMega328P Arduino UNO for reducing the design complexity while improving the
performance and flexibility of the system. With the application of Arduino UNO, I was able to
include reference frequency of 500 Hz for processing the direction of the obtained radio signal.
Through the application of Arduino, I was able to generate four signals for switching antennas.
The application of four switching signals has allowed me in obtaining the clarity for the signal
processing.
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CE 1.3.5: Plan for producing creative and innovative work
In order to keep the proposed system simple and compact I have used Arduino for
implementing the signal processing unit for the receiver system. I have further used
SoundDoppler V1.20 software for carrying out the testing process for the receiver signal system
prototype developed using pseudo-Doppler. Through the application of the software, I was able
to conduct the frequency and filtering comparison and evaluation with the application of visual
display. I have further synchronized and calibrate the audio and switching signals from the FM
radio. Therefore, for conducting the complete testing and calibration of the radio detection
system, I have developed a mobile testing platform near our university. I have used VHF
amateur radio repeaters having operating frequency if 146.67 MHz and handheld transmitter
operating at 146.5 MHz frequency for detecting the appropriate direction of the signal source.
CE 1.3.6: Collaborative work
I have worked with two other team members for the implementation of the prototype
model of the radio frequency source detection. I have worked in a corporative manner with the
team members discussing the plan for implementation and developing the prototype model. In
addition to that, I have communicated with the team members for obtaining the information from
testing phase in order to develop the detailed documentation.
CE 1.4: Project Review
CE 1.4.1: Project Overview
After completing the test for the developed prototype model, I was successful in detecting
the accurate direction of the radio signals. The application of arduino has allowed me to develop
a light weight and simple application for radio detection. The application of and COTS
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magmounts has allowed me in developing the acute functionality for the identification and
detection of the radio signals. In addition to that, the application of the different hardware
elements has allowed me to provide the final low cost radio source detection system. Moreover,
I have further carried out the physical testing of the developed prototype model for evaluating
the applicability and simplicity of use.
CE 1.4.2: My contribution to work
In spite of working as a team members for the development of the radio detection system,
I have engaged myself with the integral part for planning, implementation and testing phase. I
had the experience in working with the circuit design and radio communication technology from
my academic experience and past projects. I have used my skills and knowledge in this project
for the development of the appropriate design for the radio source detection system with low cost
and high performance. I was successful in completing the project within allocated financial cost
and time.
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