1. Hardware
  2. KK5JY SWR Meter
  3. KN9B SWR Meter/h3>
  4. Pic Kit
  5. The Bruene Directional Coupler
  6. 40dB Resistive Tap
  7. Install the IDE
  8. Programming
  9. I2C LCD - Setup instructions
  10. Video - How a Directional Coupler in an SWR meter works
  11. References







KN9B SWR Meter/h3>


Pic Kit


The Bruene Directional Coupler


40dB Resistive Tap


Install the IDE

On Ubuntu:


Do not use "apt install arduino " on Ubuntu!

WARNING!!! If you use sudo apt-get install arduino you will probably get an extremely outdated and possibly non-standard version of the Arduino IDE. Official Linux 32 bit, 64 bit, and ARM builds are available for downloadm from

Unfortuantly, I discovered this too late and waisted time installing the the Ubuntu distribution. When it did not work and complained about COM1 ports not being available I knew something was wrong.
Get the install media form

I then used this site which worked out of the box:

Always check the current permissions and owner/group of the serial device.

If you had to add the dialout group to the user, you will need to log out then log back in and now you should have access to the device.

Plug in USB device with nano with a MEga382P chipset
dmesg to locate the ttyUSB0

Select Tools-->Board-->Nano with ATmega382
I had to change the bootloader selection to the old bootloader.



Programming reference: file:///usr/share/doc/arduino-core/reference/index.html


I2C LCD - Setup instructions

Video on how to connect an I2C LCD Display to an Arduino NANO:


Video - How a Directional Coupler in an SWR meter works

This video describes how a dual directional coupler that is used in an SWR meter operates. It describes and demonstrates how voltages are developed that are directly proportional to the forward and reflected signals on a transmission line. The coupler shown is a common designed used by ham radio homebrewers in their SWR meter designs. It is widely published, and can be found in several issues of the ARRL Handbook.



Glenn Lyons VK4PK
Ver:gnl20182018 - pre published v0.9