Introduction :
Generally Automatic Atu are very expensive.
However the atu is composed essentially of relays commanding inductors and capacitors. Most of the time the L match circuit is used. For several months I have been thinking about a way to make one around an Arduino and using economic cards. It will not be necessary to spend more than 70$ for an ATU of 100W.
In addition it can be installed outdoors and controlled remotely by an rs485 link
ATU characteristics:
- Modular design.
- Up to 100W or more (not tested)
- Tandem match detector
- Arduino nano CPU.
- Remote controller by RS485
- Balun integrated symmetric and asymmetric output
- Can be installed outdoors
- SWR and POWER meter.
- Ajustable trigger power (lower than 1W)
- Simple protocol between ATU and remote control
- Cost 70$ max without box
The ATU is based on modular cards:
- Arduino
- 12V Relais x8 (two cards)
- 12V Relais x2
- 4×20 LCD display.
- PCF8574 expander.
- Specials PCB for detector
Pcb available mail me : f4goh@orange.fr
Projets radio 