According to ARRL’s Logbook of the World, FT8 is far and above the most popular mode in ham radio today. Once you have your radio interfaced to your PC getting on the air with FT8 is pretty easy.

One of the design goals for CTR2 was to provide all of my radios with a simple PC USB interface. With CTR2, once you connect any radio to a Radio I/O module you have a USB audio interface and you’re ready for digital modes.

This post will step you through the process of setting CTR2 up with WSJT-X. Similar steps would be followed for any other 3rd party digital apps.

CTR2 includes a USB sound card interface. The Teensy audio adapter board in CTR2 provides the analog to digital conversion. Once in digital form audio can be sent to your PC via the micro-USB port on the Teensy processor board.

The micro-USB port also provides a virtual serial port that emulates a Kenwood TS-2000 radio. CTR2 converts the Kenwood CAT commands sent from your app to CAT commands to control the selected radio.

All of this means that you configure your 3rd party app once and you’re done. There’s no need to change configurations when you switch to another radio.

The following instructions assume you have your radio connected to CTR2 and a USB port on your PC is connected to the micro-USB connector on the Teensy processor board on the HMI.

Locate the Teensy’s Virtual Serial Port

When you plug your PC into the Teensy’s micro-USB port the PC automatically maps the audio and serial ports on the USB connection.

In Windows 10 to find the COM port assigned to the virtual serial port simply right-click on the Start menu in the bottom left corner of your display and select Device Manager. From there, scroll down to the Ports (COMM & LPT) section. You’ll find a list of the COM port assignments. Look for the entry for USB Serial Device. The COM port listed on this entry will be the one you’ll use in your 3rd party app. If there are two or more USB serial devices listed, simply unplug the USB connection to the Teensy processor. The port that drops off the list is the one you’re looking for.

Here’s a screen shot of my Windows Device Manager window. CTR2 is using USB Serial Device (COM6).

On Linux navigate to the /dev/ folder and look for a file titled ttyUSBx, where x= the port #. On my system I only have ttyUSB0 so that’s the one I selected in WSJT-X. If there are are two or more of these files, just try each one until WSJT-X sees CTR2.

I don’t have a Mac so Google is your friend here.

Configure WSJT-X

In WSJT-X, navigate to File –> Settings… From here, click on the Radio tab. The screenshot below shows the settings I use.

Rig: Kenwood TS-2000

Poll Interval: 6 seconds – I’ve found that slowing the polling rate down minimized data error messages in WSJT-X.

Serial Port: COM6

Baud Rate: 1200 – I’ve had better luck using the lowest baud rate with CTR2

The other settings can be left at their default values.

Once you’ve changed your settings click the Test CAT button. It should turn green indicating successful communications with CTR2.

Next, click the Audio tab. On this tab, select the Digital Audio Interface (Teensy MIDI/Audio) device in the Soundcard Input and Output boxes. Also, select Mono for each port. There may be a number preceding the Teensy MIDI/Audio description. Mine has a ‘4-‘. The important part is to find the Teensy I/O ports.

Once you’ve completed these steps you can click OK to close this window.

Configure CTR2

In CTR2, touch either the Radio Mode or Operating Mode buttons in the lower left corner of the Home page. This opens the MODE SELECT page. Once here, touch the Digital button in the Op Mode column. This automatically select USB for the Radio Mode. Touch [<–] to return to the Home page.

Back on the Home page, touch the Settings button to open the DIGITAL SETTINGS page.

The settings on this page are explained in the UI Modes and Settings post. The settings above are what I use. Make sure you select USB for Tx Audio In and Rx Audio Out to use the USB connection to your PC. I also like to monitor the audio so I enable Monitor = ON. You can turn this off if you don’t want to hear the audio on the radio. I like to leave the Tx Level set to around 50% and I use the gain control in WSJT-X to make fine adjustments. You can also use the encoder to adjust the Tx Level during transmit.

You may also find that the default level settings in CTR2 are either too high or to low to work with your radio and WSJT-X. You can do course level adjustments on CTR2‘s AMP LEVELS page. To get to this page, touch the Config button on the Settings page above to navigate to the CONFIGURATION page then touch the Levels button to navigate to the AMP LEVELS page shown below.

On this page you can adjust the various amps within CTR2 to match the 3rd party app to your radio.

All settings will be saved to the selected radio’s .INI file when you’re done.

Going on the Air

Once you have everything set up it’s time to try it out. Return to CTR2‘s Home page and make sure the Radio Options button in the bottom left corner shows Tx Off. In WSJT-X, click the [Tune] button. WSJT-X will generate a solid tone on the frequency you’re selected. If everything is working you should hear the tone in your headphones (if you have the Monitor Tx/Rx Audio option turned ON, and see the tone on the FFT display at the selected frequency. Unclick the [Tune] button and the tone should stop.

If everything is working to this point, it’s time to set the transmit level level on your radio. Connect it to a dummy load then on CTR2 touch the Radio Options button. When the RADIO OPTIONS page appears click the Tx Off button. This will toggle the Tx Enable interlock and you’ll be returned to the Home page. The Radio Options button should now be green, indicating transmit is enabled.

In WSJT-X, click the [Tune] button again. This time your radio should key (assuming you set CTR2‘s VOX to key PTT on your radio and you have PTT wired). Adjust your mic gain or Line-In gain as specified by your radio’s user manual. Every radio is different but you usually set this with the ALC meter. I also like to watch the power out and set the Tx Level so the radio is operating just below its selected power setting. Unclick the [Tune] button.

If you’ve made it this far, connect your radio to your antenna and select the CQ message on the WSJT-X message list. Click [Enable Transmit] in WSJT-X. When your transmit window time arrives, your radio should key up and transmit your CQ. Be ready for replies! To verify signal coverage I like to use PSK Reporter at This is great tool for checking your transmitted signal.

Finally, a big warning!!

WARNING! Windows has a nasty habit of switching audio ports around, especially after a Windows update. I’ve had this happen a couple of times. If the audio port assignments get changed to SPEAKER or MIC and CTR2 is set for VOX and has Tx Enabled, it will key your transmitter and broadcast your PC’s speaker audio over the air! Always set CTR2 to Tx Off when you’re not operating.