Automated Antenna Controller

Our Team Sam Bryan – Team Leader Electrical Engineer Hardware Prototyping LCD Communication Brandon Gray Electrical Engineer Hardware Prototyping Frequency Counting Jacob Edwards Computer Engineer Microprocessor Programming Ashley Stough Electrical Engineer LCD Communication Frequency Counting Dr. Raymond Winton Academic Advisor Sponsor

Outline IntroductionIntroduction ProblemProblem SolutionSolution ConstraintsConstraints –Technical –Practical Special ConcernsSpecial Concerns –Manufacturability –Health and Safety System OverviewSystem Overview ProgressProgress TimelineTimeline QuestionsQuestions

What is the Automated Antenna Controller? –Microprocessor controlled version of MFJ Enterprises, Inc.’s user-managed loop antenna controller –Used with MFJ-1786 and MFJ-1788 Super Hi-Q Loop Antennas [1]

What is the Automated Antenna Controller? (cont’d) Unit controls a motor attached to a variable plate capacitor which adds capacitance to the impedance of the loadUnit controls a motor attached to a variable plate capacitor which adds capacitance to the impedance of the load Standing Wave Ratio (SWR)Standing Wave Ratio (SWR) –Ratio of power or impedance: Power reflected to source versus power transmitted from sourcePower reflected to source versus power transmitted from source Load impedance against source impedanceLoad impedance against source impedance

Problems 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]

Solution Use microcontroller to allow more accurate tuningUse microcontroller to allow more accurate tuning Automate the tuning process to avoid user errorAutomate the tuning process to avoid user error Utilize digital display to allow easier output for userUtilize digital display to allow easier output for user

Technical Constraints NameConstraint Frequency Frequency must measure and display between 7 and 30MHz ± 30kHz. Standing Wave Ratio A maximum of 3:1 SWR must be achieved. Connector RF connection must be an SO-239 style connector. RF Power Forward and reflected power must be measured and displayed accurately to ± 1W. Power Supply Power supply must be the MFJ-1312D AC adapter.

Manufacturability: Size Large enough to accommodate analog and digital displaysLarge enough to accommodate analog and digital displays Within reason from previous modelWithin reason from previous model Suggested Size: 4in x 7in x 7in.Suggested Size: 4in x 7in x 7in. [3]

Health and Safety Enclose the controllerEnclose the controller –Prevent electric shock –Prevent burns from hot components –Prevent RF burns

System Overview

Microcontroller [4] Previous Experience Available from Manufacturer PWM PortsPrice PIC 160 membersYes1$2.97 PIC 18F membersYes2$3.98

LCD BacklightSupplied by Manufacturer Price WH-1602B- NGB NoYes10.40 WH-1602B- GGE Yes, Green Yes10.40

SWR Measurement [6] [7] Indirect Direct

SWR Measurement (cont’d) Effect on transmission line Frequency dependency Output IndirectNoneIndependentRepresentative voltage DirectIntroduces impedance DependentRepresentative voltage

Timeline MonthAugustSeptemberOctoberNovember Research Hardware Prototyping Programming Testing Operational Prototype

Progress PrototypingPrototyping TestingTesting

Prototyping

Testing

Testing (cont’d)

Summary ProblemProblem SolutionSolution ConstraintsConstraints –Technical –Practical Special ConcernsSpecial Concerns –Manufacturability –Health and Safety System OverviewSystem Overview Trade-offsTrade-offs TimelineTimeline ProgressProgress

References [1] [Online]. Accessed: September 29, [2] [Online]. Accessed: September 27, [3]MFJ Enterprises, INC., MFJ Super Hi-Q Loop Antenna: Model MFJ 1786/1788 Instruction Manual, [4] 8f2520-i%20sp.JPG. [Online]. Accessed: September 30, [5] “PIC18F2420/2520/4420/4520 Datasheet”, Microchip Technology Inc. pg 326. [6] Owen Duffy 1995, 2006[Online]. Accessed: October 6, [6] Owen Duffy 1995, 2006 [Online]. Accessed: October 6, [7] [Online]. Accessed: October 6, 2009.

Questions?