Automated Antenna Controller

During Senior Design 2 our team has completed the prototyping of the Automated Antenna Controller that works with the MFJ-1786(shown below) and MFJ-1788 Loop Antenna.

The loop antenna works with a seperate control unit that tunes the antenna based on what frequency the radio operator decides to transmit. Inside the housing of the antenna there is a variable capacitor that is rotated by a small motor. By utilizing a microprocessor to control the motor, the control unit is able to effectively tune the antenna automatically without any user input. The control unit tunes the antenna until a 3:1 SWR or below is seen and then the user can fine tune the antenna to optimize the SWR to as low as 1.1:1

The following is a video of the AAC's operation.

During Senior Design 1 our team has been redesigning an Analog User Tuned Loop Antenna controller into a Digital Automated Antenna Controller. The current control unit is in use with the MFJ-1786 (10-30 MHz) and MFJ-1788 (7-21 MHz) Loop Antennas.

For an explaination on how this is acheived, explore the Senior Design 1 Photo or Senior Design 2 Photo pages for a visual runthrough of the system.

• Forward and Reflected Power - Taking ADC values
• SWR (Standing Wave Ratio)
• Frequency Counting and Frequency Division
• D Flip-Flops and 8 Bit Counters
• PWM (Pulse Width Modulation)
• PIC18F2520 Programming
• H-Bridges and Motor Control