A Microcontroller Operated SWR Meter

1 Project description

This project is part of the SVXLink project. Since I intend to use T7F transceivers for this project, it is highly interesting to detect troublesome antenna and SWR conditions and to be able to shut off the transmitter. The only way to do that is to read out the SWR digitally. And this can be done using the I2C BUS.

BTW, I want to measure some more values:

• PA temperature
• Transmitter power consumption / input current
• Total system input current

And I want to switch some things, too:

• Be able to switch the transceiver OFF

2 Other People's work

• http://www.dj4uf.de/projekt/swr/swr.htm - cool idea for a simple directional coupler. I see that a Aircell cable is perfectly suited for this job.
• http://accrochages.drone.ws/en/node/125 - a voltage meter project based on the Arduino
• http://www.electronics-lab.com/blog/?p=2092
• http://www.youritronics.com/100w-vhf-uhf-lcd-pic16f88-swr-meter/

3 Progress

• 2009-09-04 The BeagleBoard has an I2C header in the expansion port. So it is just a wonderful idea to use it and read out some things. The only problem: It's operated with 1,8V. So I need a bidirectional voltage translator.
  • I found one across the Atlantic at Ebay: Gravitech has such a thing for a decent price: http://gravitech.us/MicroResearch/I2C/I2C-TRN/I2C-TRN-Manual.pdf
  • Another option would be to built it by myself using the PCA9306: http://focus.ti.com/docs/prod/folders/print/pca9306.html
• 2009-09-05 I decided to get the one from Gravitech.

• Come back and see in a few weeks / months...