Automated Antenna ControllerAutomated Antenna Controller

Our TeamOur Team

Sam Bryan – Team LeaderSam Bryan – Team LeaderElectrical EngineerElectrical Engineer

LCD HardwareLCD HardwareLCD SoftwareLCD Software

Power CalculationsPower Calculations

Brandon Gray Brandon Gray Electrical EngineerElectrical Engineer

Hardware PrototypingHardware PrototypingFrequency CountingFrequency Counting

RF CouplerRF Coupler

Jacob EdwardsJacob EdwardsComputer EngineerComputer Engineer

LCD SoftwareLCD SoftwareFrequency CountingFrequency Counting

Motor Control SoftwareMotor Control Software

Ashley StoughAshley StoughElectrical EngineerElectrical Engineer

Motor Control HardwareMotor Control HardwareFrequency CountingFrequency Counting

HardwareHardware

Dr. Raymond WintonDr. Raymond WintonAcademic AdvisorAcademic Advisor

SponsorSponsor

OutlineOutline• ProblemProblem• SolutionSolution• ConstraintsConstraints

– TechnicalTechnical– PracticalPractical

• Special ConcernsSpecial Concerns– ManufacturabilityManufacturability– EconomicsEconomics

• System Overview System Overview • Subsystem TestingSubsystem Testing• System TestingSystem Testing• GoalsGoals

What is the Automated Antenna What is the Automated Antenna Controller?Controller?

– Microprocessor controlled version of MFJ Microprocessor controlled version of MFJ Enterprises, Inc.’s user-managed loop Enterprises, Inc.’s user-managed loop antenna controller antenna controller

– Used with MFJ-1786 and MFJ-1788 Super Used with MFJ-1786 and MFJ-1788 Super Hi-Q Loop Antennas Hi-Q Loop Antennas

[1][1]

What is the Automated Antenna What is the Automated Antenna Controller?Controller? (cont’d) (cont’d)

• Unit controls a motor attached to a variable plate capacitor Unit controls a motor attached to a variable plate capacitor which adds capacitance to the impedance of the loadwhich adds capacitance to the impedance of the load

• Standing Wave Ratio (SWR)Standing Wave Ratio (SWR)– Ratio of power or impedance: Ratio of power or impedance:

• Power reflected to source versus power transmitted Power reflected to source versus power transmitted from sourcefrom source

• Load impedance against source impedanceLoad impedance against source impedance

Problems with Existing ControllerProblems with Existing Controller

• Operation is Time ConsumingOperation is Time Consuming

• Unit is Difficult to OperateUnit is Difficult to Operate

• Meter is Difficult to Read AccuratelyMeter is Difficult to Read Accurately

• Inaccurately controlledInaccurately controlled

[2][2]

SolutionSolution

• Use microcontroller to allow more accurate Use microcontroller to allow more accurate tuningtuning

• Automate the tuning process to avoid user Automate the tuning process to avoid user errorerror

• Utilize digital display to allow easier output Utilize digital display to allow easier output for userfor user

Technical ConstraintsTechnical ConstraintsNameName ConstraintConstraint

FrequencyFrequency Frequency must measure and display between 7 and Frequency must measure and display between 7 and 30MHz ± 30kHz. 30MHz ± 30kHz.

Standing Wave RatioStanding Wave Ratio A maximum of 3:1 SWR must be achieved.A maximum of 3:1 SWR must be achieved.

ConnectorConnector RF connection must be an SO-239 style connector. RF connection must be an SO-239 style connector.

RF PowerRF Power Forward and reflected power must be measured and Forward and reflected power must be measured and displayed accurately to ± 1W. displayed accurately to ± 1W.

Power SupplyPower Supply Power supply must be the MFJ-1312D AC adapter.Power supply must be the MFJ-1312D AC adapter.

Health and SafetyHealth and Safety

• Enclose the controllerEnclose the controller– Prevent electric shockPrevent electric shock– Prevent burns from hot componentsPrevent burns from hot components– Prevent RF burnsPrevent RF burns

Economics: Manufacturing CostEconomics: Manufacturing Cost

• Parts must already be in stock at MFJParts must already be in stock at MFJ– Reduces number of parts orderedReduces number of parts ordered– Limits design optionsLimits design options

Visual System OverviewVisual System Overview

TestingTesting• Subsystem TestingSubsystem Testing

– SWR and Power MeasurementSWR and Power Measurement– Frequency MeasurementFrequency Measurement– Antenna Tuning CircuitAntenna Tuning Circuit– DisplayDisplay

• System TestingSystem Testing

SWR and Power MeasurementSWR and Power Measurement

SWR and Power MeasurementSWR and Power Measurement

[6][6]

Power MeasurementsPower Measurements

Voltage from RF Coupler to ADC inputVoltage from RF Coupler to ADC input

Power MeasurementsPower Measurements

SWR MeasurementsSWR Measurements

Frequency MeasurementFrequency Measurement

Frequency MeasurementFrequency Measurement

D Flip-Flop InputD Flip-Flop Input D Flip-Flop OutputD Flip-Flop Output

D Flip-Flop Input/128 = D Flip-Flop OutputD Flip-Flop Input/128 = D Flip-Flop Output

Antenna Tuning CircuitAntenna Tuning Circuit

H-BridgeH-Bridge Variable CapacitorVariable Capacitor

Antenna Tuning CircuitAntenna Tuning Circuit

PWM InputPWM Input H-Bridge OutputH-Bridge Output

• Fast Tune and Slow TuneFast Tune and Slow Tune•No feedback from MotorNo feedback from Motor•Tune Down the Antenna to the lower limitTune Down the Antenna to the lower limit

DisplayDisplay• FrequencyFrequency•SWRSWR•Forward / Reflected PowerForward / Reflected Power

System TestingSystem Testing

• Testing with the Dummy LoadTesting with the Dummy Load

• Testing with the Loop AntennaTesting with the Loop Antenna

Prototype PerformancePrototype Performance

Technical ConstraintTechnical Constraint Constraint MetConstraint Met

Frequency must measure and Frequency must measure and display between 7 and 30MHz ± display between 7 and 30MHz ± 30kHz. 30kHz.

YesYes

A maximum of 3:1 SWR must be A maximum of 3:1 SWR must be achieved.achieved.

YesYes

RF connection must be an SO-RF connection must be an SO-239 style connector. 239 style connector.

YesYes

Forward and reflected power Forward and reflected power must be measured and must be measured and displayed accurately to ± 1W. displayed accurately to ± 1W.

YesYes

Power supply must be the MFJ-Power supply must be the MFJ-1312D AC adapter.1312D AC adapter.

YesYes

Design II GoalsDesign II Goals• Analog SWR/Power MeterAnalog SWR/Power Meter

• User Interface ButtonsUser Interface Buttons

• Capacitor Limitation Sensing Capacitor Limitation Sensing

• PCB DesignPCB Design

• Product PackagingProduct Packaging

References References

[1]http://www.mfjenterprises.com/Product.php?productid=MFJ-1786.[1]http://www.mfjenterprises.com/Product.php?productid=MFJ-1786.[Online]. Accessed: September 29, 2009.[Online]. Accessed: September 29, 2009.

[2]http://www.mfjenterprises.com/catalog/Pages_061-080.pdf [Online]. [2]http://www.mfjenterprises.com/catalog/Pages_061-080.pdf [Online]. Accessed: September 27, 2009.Accessed: September 27, 2009.

[3]MFJ Enterprises, INC., [3]MFJ Enterprises, INC., MFJ Super Hi-Q Loop Antenna: Model MFJ MFJ Super Hi-Q Loop Antenna: Model MFJ 1786/1788 Instruction Manual1786/1788 Instruction Manual, 1997., 1997.

[4]http://media.digikey.com/photos/Microchip%20Tech%20Photos/[4]http://media.digikey.com/photos/Microchip%20Tech%20Photos/pic18f2520-i%20sp.JPG. [Online]. Accessed: September 30, 2009. pic18f2520-i%20sp.JPG. [Online]. Accessed: September 30, 2009.

[5] “PIC18F2420/2520/4420/4520 Datasheet”, 2008. Microchip [5] “PIC18F2420/2520/4420/4520 Datasheet”, 2008. Microchip Technology Inc. pg 326.Technology Inc. pg 326.

[6]http://vk1od.net/transmissionline/VSWR/VSWRMeter.htm. Owen [6]http://vk1od.net/transmissionline/VSWR/VSWRMeter.htm. Owen Duffy 1995, 2006Duffy 1995, 2006 [Online]. Accessed: October 6, 2009.[Online]. Accessed: October 6, 2009.

Questions?Questions?