Last modified 17 months ago Last modified on 10/17/15 17:30:35

Using fldigi with the Signature series of Flex Radios.

The Signature Series of Flex Radios are the 6300, 6500, and the 6700. While each radio has different features, the fldigi setup is the same for all of the radios.

The radio in this case, is a Flex Radio 6300, a two slice transceiver. The computer was a Dell duo core desktop running Windows 10. We will assume that you understand the basic operation of the FlexRadio?.

I have also used this radio and procedure in Windows 7 on an iMac running Bootcamp, the setup is identical.

As always, start your flex radio, and then fldigi.

To configure fldigi, you use RigCAT It’s under Rig configuration, tabs second row down, second tab from the left.

Click to enable Use RigCAT .

You need to download the SmartSDR-SliceA.xml from You might as well download SmartSDR-SliceB.xml while you are at it. Make certain that the XML files are placed in your fldigi.files/rigs folder. You should only need the SliceA file to set up fldigi, however.

Slice A link

Slice B link

Rig Settings:

Open the Rig description window and select SmartSDR-SliceA.xml file.

The other rig settings:

device Com4

Baud rate 115200

Stopbits 1

Retries 5

Retry interval 200

Write delay 5

Init Delay 300

Check Cat Command for PTT

Check VSP Enable

Leave the other check boxes unchecked.

The initialize box should show red text at this point. Click it. Save it, and close the window

At this point, you should have rig control. Try changing bands or other fldigi rig functions.

If the rig doesn’t respond, reopen the Rig control window, and check the Device options. You might need to check a different com port, depending on your FlexRadio? setup. If you see a Com5, try that one. Initialize and save and close again.

Your radio and fldigi should be talking with each other by now.

If still no joy, open your SmartSDR CAT program and check to see what com port it is expecting to connect third party programs with. This info is on the main window of the program You may need to add a port in the SmartSDRCat program if you do not see anything, then repeat the rig control process.

Note that for some reason SmartSDR CAT wants you to go to the show hidden icons on the task bar to open the SmartSDR CAT window, so look for it there.

Getting sound to and from fldigi

Under Configure / Soundcard, you should check the PortAudio? check box.

You will see a veritable dog’s breakfast of choices here. Don’t be intimidated.

Capture should be set to DAX Audio RX1 (DAX RX Audio)

Playback should be set to DAX Audio TX 1 (DAX TX Audio)

On my setup, I also open the Right Channel Tab, and under Transmit Usage, I check Modem signal on left and right channels Click Save and Close.

You should now have audio connected between the two programs.

Some non-fldigi notes that may help you if you are having problems:


In the Flex Radio P/CW window, make certain you have DAX chosen.

In the Slice Window, click on the DAX tab, and make certain that you have Channel 1 enabled.

In the RX Window you should have DIGU mode selected, and the Bandwidth set to 3.0K note you can run USB mode also, it will just cut off the very lowest and highest portions of the passband.

Do not forget to save your settings as a Global profile in the FlexRadio?.

This should get you started in fldigi use with the Flex signature series radios. Questions or comments will be appreciated to help make this page more comprehensive and helpful.

  • 73 Mike N3LI -