Home W2 Firmware and Utility

W2 Firmware and Utility

W2 Current Production Firmware:

V1.00, 4-12-2010

All W2 SWR/Power meters ordered today will have Product Firmware loaded as they come out of the box. Monitor the Elecraft Email Reflector where announcements are made when new releases become available. 

Elecraft delivers new features in firmware. As a result, you should consider the Release Notes as an extension of the Owner's Manual. Documentation for the new features will be found there and will not appear in the Owner's Manual until the next major manual revision is released.

Current Production Firmware Release Notes

  • SWR ACCURACY: As a result of our continuing product improvement, a different algorithm is now used to calculate the SWR value. Besides offering greater accuracy at lower power levels, the SWR data available from the Serial Port now reports the range of 1.00:1 to 99.99:1, giving much finer resolution of SWR readings.
  • SWR ALARM CHANGES: The trip points for the SWR Alarm now match the SWR LED’s on the front panel of the W2. The range is still 1.1:1 to 5.0:1. Sending the W2 a “[” lowers the trip point, and “]” raises the trip point. Note the decimal point is implied in the serial response, i.e. “[25;” means the trip point was lowered to an SWR of 2.5:1 and “]40” means the trip point was raised to 4.0:1.
  • SWR ALARM RESPONSE TIME: You can use the “PTT RY” RCA connectors on the back of the W2 to help protect your amp in case of high SWR. The response time that it takes for the relay to trip has been improved and can now catch an “I” sent at 60 WPM.
  • SERIAL COMMAND CHANGES: The Serial Command set has had some minor changes in output format. 
  • See W2 Firmware Release Notes for complete revision history
  • Download the latest W2 Firmware.

Important - Please read before installing the latest Production Firmware

If you have firmware older than indicated below, please be sure to follow the steps below.

***No special instructions at this time***

Production Firmware Installation Instructions are found in the Utility

  • All Production Firmware is loaded with the W2 Utility. It will take care of the download and installing Production Firmware
  • Before loading Production Firmware, please ensure you have installed the latest version of the W2 Utility.
  • See the Help → Getting Started pull-down menu in the W2 Utility for the steps to install firmware in your W2.


Download and Install the W2 Utility for your Operating System

Follow the links below to download and install the latest version of the Utility for your Operating System.

You will be connecting the W2 to the computer with a KXUSB cable that was included with the W2 when it was shipped from the factory.


Minimum Operating System Requirements for Elecraft Utilities 

Microsoft Windows: XP Service Pack 3 or later, including Vista, 7, 8, and 8.1 and 10.
Apple Mac: OS X 10.6 (Snow Leopard) or later


 Windows W2 Utility (Windows Version February 27, 2010
  • This is an auto-installer file.  Download and run the file from the above link.
Macintosh W2 Utility (MAC OSX 64bit Version September 13, 2019
  • Files are in unversal binary in .zip file.
X86 Linux

W2 Utility (Linux 64bit Version September 13, 2019

  • Files are in TAR archive (gzip-compressed) format.


The following libraries and dependencies should be installed on your Linux distro:

GTK+ 2.8 or later, glibc-2.4, libstdc++.so.6 and cURL. 64-bit Linux requires 32-bit compatibility libraries.

Installing the FTDI driver Follow this link to the FTDI Site for drivers: http://www.ftdichip.com/Drivers/VCP.htm

Depending on the Operating System you have, the driver needed for the Utility to communicate with the W2 will need to be loaded.

All Elecraft products in production use the FTDI chipset for this function. The FTDI driver allows your computer to create a virtual COM port so that the Utility can communicate with the Elecraft product.



W2 Wattmeter / SWR Bridge Software


The software provided for download on this page is provided as a free service to our customers and is provided as-is without warranty. 

W2 Serial Interface Commands 

W2 Automatic Power On Modification - Easy one solder jumper mod lets your W2 automatically power on/off with +12VDC from your K3 or your shack's master power supply.


Elecraft W2 Interface program (Ver

Please note this version requires at minimum W2 Firmware Rev 1.00.

Main Form (Windows version)


Setup Form (Windows version)

Read about the latest updates in this version

W2 Interface (Windows Version)
  • Note this link now connects directly to a third party Server.
  • Download the file to your PC.
  • Unzip the file and click on the executable file to run the program.
W2 Interface (Mac OS X Version)
  • Note this link now connects directly to a third party Server.
  • Download the file to your Mac.
  • Files are in universal binary in .zip file.


Beta Firmware Installation and Release Notes

No Beta Firmware candidate at this time

 Beta Firmware Release Notes

    Beta Test Firmware Installation Procedures

    NOTE: Beta test firmware may have new issues that we haven't caught during field testing. Please report them to support@elecraft.com.

    A little more detail

    We make it a little harder to load Beta firmware mainly because we want you to be sure you want to do this.  Beta firmware means that, while the W2 engineering team has fully tested the firmware, it has not yet been deemed ready for Production status.   You can always return to the last firmware you have downloaded by following the steps in the W2 Utility’s Help section.

    To load Beta Firmware, follow the steps below:

    1. Create a new folder for the beta firmware on your Desktop or some other easily found location. Use the a different folder than the default folder found in the Firmware tab of the Utility. In this way, you can revert to the last Production firmware easily.

    2. Now, we will download the firmware in Zip file format. In a web browser, type in this URL:


    If you do not see the correct version of the zip file, press the RELOAD / REFRESH button on your browser to update your browser cache.

    3. Right-click on the .zip file containing the beta firmware.  Save the file to your beta folder you just created.

    4. Unzip the files into the beta folder.

    5. Enter the path to the beta folder in W2 Utility → Firmware tab → "Local folder for firmware files".

    6. After you have made the change in Step 5, make sure you *DO NOT* check the W2 Utility box titled "Copy new files from Elecraft server". This will overwrite the Beta firmware if clicked.

    7. Connect the W2 to your computer and be sure it is turned on. Select the Firmware tab and Click on "Check versions now" button. 

    8. Review the release notes. To find them, select the "Help" pull-down menu.

    9. Click "Send all firmware to W2." This will cause the firmware to be sent to the W2. You will see that the W2 appears to restart itself. Monitor the Activity Log until it is complete.

    10. After completing a new software download to your product, please power cycle the W2 OFF and then back ON before using it.

    11. Please report any new firmware issues to support@elecraft.com