Screwdriver Dipole Antenna Tuner Project

Jul 31, 2021 | Uncategorized

  1. Scope of document

Building an automatic antenna controller for two screwdriver antennae, mounted semi-colinear with facing mount points. Identification of required concepts, description and design of hardware and software components.

  1. Required functions/features

 Hardware aspect

  1. a) Driving motors of each antenna with recognition of start and end position
  2. b) Variable motor speed for fine tuning of the antennae
  3. c) Counting motor revolutions when antenna is moving
  4. d) Measuring forward and reflected power for SWR calculation and automatic fine tuning
  5. e) Measurement amplifier for output of directional coupler with range switch for 0-200W and 0-2000W
  6. f) Tuning module with relays for matching capacitors when required
  7. g) Serial interface for CAT commands from Transceiver
  8. h) Second serial interface to relay CAT commands to amplifier if required
  9. i) Ethernet interface for remote control
  10. j) USB interface for firmware updates
  11. k) Serial interface for touch screen
  12. l) Parallel interface for keypad
  13. m) Touch screen for display and control

 Software aspect

  1. a) Turn count and matching C memory (min, max) for each band, 160m, 80m, 40m, 30m, 20m, 17m, 15m, 12m, 10m
  2. b) Calibrate to 0 when power off at bottom
  3. c) Remember position when powered off
  4. d) Speed control for motor, slow for fine tuning
  5. e) Monitor motor voltage and stop motor power when at top or bottom
  6. f) Allow entry of turn count via keypad
  7. g) Manual control for each antenna (Up, Down, Park)
  8. h) Mode for single antenna and dipole antenna
  9. i) Store SWR for each band and tune when saved
  10. j) Store recent SWR for each band
  11. k) Separate memories for different whip sizes
  12. l) Seek function (slow motor) for each band
  13. m) Count range for seek function
  14. n) Web interface for stored value display
  15. o) Web interface for change of settings
  16. p) Web interface for remote control
  17. q) Reading band changes of transceiver via serial interface
  18. r) LCD display output for settings and value visualisation
  19. s) Touch display functions for manual control and display screen selection

  Hardware components / modules

  1. Arduino Mega
  2. Ethernet shield
  3. Relay Board
  4. Display adapter
  5. SWR bridge
  6. 4D touch screen
  7. Foil keyboard
  8. Power supply, regulated 7V (Arduino)
  9. Power supply, regulated 12V (SWR Bridge)
  10. Power supply, regulated 5V (Display, other components)
  11. Power supply 6-12V with digiPot for variable motor speed
  12. Flip/Flop switch for momentary power button
  13. Measurement amp for SWR bridge output (2 channel op-amp amplifier)
  14. Current meter for motor drive current (2 channel – one for each antenna)
  15. Matching module with relays and capacitors for automated capacitive matching

 

Display Screen Design

Some first designs for the 4.3" touch screen. Will be refined and extended.