Digital Communications: Chromebook

Background:

May 2026 - The Club seemed to need a separate computer to enable Digital Communications on the Yeasu FTDX101D tranciever.

The UW's requirement for shared sign-in computers on the network restricting installation of software required a solution that was a computer not using UW IT resources. The solution was a Chromebook running Linux OS with OS Verification disabled. This allows the Chromebook to operate off-line.

There are 2 programs installed in the Linux file system WSJTX, and FLDIGI. This will allow the operator to run most popular Digital Modes.

Connection to the Yeasu FTDX101D is via USB port connection on the back of the radio. The FTDX101D has a Baud Rate of 38,400.

Booting the Chromebook:

The Chromebook is plugged into a constant power outlet on the back of the station surge suppressor and is normally running though it may be asleep. To return the Chromebook from Sleep, mouse around on the trackpad, it should wake up and display an open Terminal Window with a w9ytarc@penguin prompt. The USB port will already be initialized, and it is ready to talk to the RTDX101D.

In the case that someone errantly shut off the Chromebook or Unplugged it, follow this proceedure:

Push the power button on the upper right side of the keyboard and wait for the display to come up. It will boot to a white screen indicating OS verification has been shut off.

>>>DO NOT TOUCH THE SPACEBAR<<< Doing so will re-enable OS Verification and initiate a reboot and wipe of the Chromebook.

When the warning has timed out, the Chromebook will issue a loud Beep and ask for the Password. The Password is 111111. Then it will boot to the basic chrome screen. The Linux OS has been loaded, and the Microphone has been assigned to LINUX, but the Shell is not running at this point. Verify the speaker output is set to about 50% using the user control panel on the far-right side of the tray (like windows).

Either on the Tray or the button on the lower left side of the tray, you'll find the Terminal Icon ">_", click on it and open the Terminal. To run the LINUX OS. click on the Penguin button. The LINUX Shell will start; when it is finished it will display a "w9ytarc@penguin" prompt. It is now ready to run WSJTX or FLDIGI.

You may need to unplug and re-plug in the USB cable at the Chromebook to reinitialize the port. Use the same exact port on the right side of the computer. When the initialization window comes up, click on "Make available to Linux".

Setting up the FTDX101D for Data Mode:

If you have not done so, there is a Mode switch on the radio on the upper right side of the screen. Press it. A selection of modes will appear, select "DATA-U" to enable the radio to accept audio from the Chromebook.

Filter Adjustment: I have observed that when DATA-U is enabled the bandpass filter may be set to 600hz. This is too narrow for viewing of the entire channel spectrum of 2500hz. To adjust it, the WIDTH knob is located on the lower right side of the front panel and is the outer ring. This will allow adjustment of the roofing filter from 600hz to 2500hz. The SHIFT knob (Inner) will allow shifting of the bandpass, this is very helpful using digital QSO modes to ensure good decodes in crowded conditions.

Starting WSJTX or FLDIGI:

At the "w9ytarc@penguin" prompt, enter < wsjtx > or < fldigi>. The Program will execute and a User Interface will appear. CAT functions will link with the radio; either adjustment from the computer or the radio will change the T/R frequency of the radio.

Setting output Power (Audio Level):

Before you make a QSO you want to set/verify the audio output level to the radio to ensure the output is distortion free.

• Set the Antenna selection on the Antenna switch to Dummy Load. Turn the power setting on the radio to no more than 50W to prevent thermal damage to the Radio's Finals. Never exceed 50W of output power from the radio; you don't need it and running digital modes generates a lot of heat due to the high duty cycle of the input signal.

• With WSJTX, click on the TUNE button. The radio should enter TX mode and output RF. Set the Slider on the Right Side so the ALC meter is no more than 50% to the Red band. Click Tune again to shut off TX.

• With FLDIGI, click on the T/R button and the radio will enter TX mode and output RF. Set the ALC level using the Speaker Output on the Chromebook using the same guidelines as above.

{Need to add Basic WSJTX and FLDIGI Operation: Chromebook Installation (separate WIKI)}