WSJT-X Setup Guide

Using WSJT-X with RimuSDR on Linux

WSJT-X connects to FlexRadio on Linux through two components of the RimuSDR suite: RimuDAX for audio routing and RimuCAT for CAT control. This guide walks through every step of the configuration in order.

Start: RimuSDR Setup WSJT-X Settings

RimuSDR · RimuDAX · RimuCAT · WSJT-X · FT8 · FT4 · JT65 · WSPR

What You Will Configure

Three components of the RimuSDR suite work together to give WSJT-X everything it needs: RimuSDR provides the radio connection and DAX channel, RimuDAX routes audio, and RimuCAT exposes a TCP CAT port.

RimuSDR

Start here. Connect to the radio and enable the DAX channel on the slice you want to use.

Connect to the FlexRadio
Set the Slice DAX channel to 1
Press the DAX button on that slice

RimuDAX

Provides the audio path. Enable TX, Mic, and RX1 channels so WSJT-X can receive and transmit.

Connect and select the same station as RimuSDR
Enable TX, Mic, and RX1 channels
Confirm the RX1 meter responds to received signals

RimuCAT

Provides the CAT control path via a TCP port that WSJT-X connects to as a FlexRadio 6xxx rig.

Connect and select the same station as RimuSDR
Create a CAT TCP connection on port 60000
WSJT-X connects to localhost:60000

Step 1 — RimuSDR: Connect and Enable DAX

RimuSDR must be connected to the radio and the DAX channel must be active on the slice before RimuDAX is started.

1. Start RimuSDR and connect

Open RimuSDR and connect to the FlexRadio. The radio will appear in the station list and the main SDR view will open once connected.

2. Set the Slice DAX channel to 1

On the slice you want WSJT-X to use, set the DAX channel selector to 1. This assigns audio channel 1 to that slice.

3. Press the DAX button

Press the DAX button on the slice to activate the audio channel. RimuDAX will pick up channel 1 when it connects.

Step 2 — RimuDAX: Enable Audio Channels

RimuDAX routes audio between the radio and the Linux audio system. Enable the TX, Mic, and RX1 channels so WSJT-X has both a receive input and a transmit output.

4. Start RimuDAX and connect

Open RimuDAX and connect to the radio. Select the same station that RimuSDR is connected to — in most setups there will only be one station in the list.

5. Enable TX, Mic, and RX1

Enable the TX, Mic, and RX1 channels. These provide transmit audio out to the radio, microphone input, and the DAX channel 1 receive audio that WSJT-X will decode.

6. Confirm RX1 is receiving

Check that the RX1 channel level meter moves in response to signals from the radio. If it is not responding, confirm the DAX button is active on the slice in RimuSDR.

RimuDAX with TX, Mic, and RX1 channels enabled — RimuDAX with the TX, Mic, and RX1 channels enabled. The RX1 meter should show activity when signals are present on the slice.

DAX setup notes

Order mattersRimuSDR must be connected and the DAX channel active before RimuDAX is started, otherwise RimuDAX will not see the audio stream.
Same stationRimuDAX must be connected to the same station (radio) that RimuSDR is using. In most home setups only one station will appear in the list.
RX1 meterA silent RX1 meter usually means the DAX button is not active on the slice, or the wrong DAX channel number is selected in RimuSDR.

Step 3 — RimuCAT: Create a TCP CAT Connection

RimuCAT exposes the radio's frequency, mode, and PTT to WSJT-X over a TCP network port. No physical serial cable is required.

7. Start RimuCAT and connect

Open RimuCAT and connect to the radio. As with RimuDAX, select the same station that RimuSDR is connected to.

8. Create a CAT TCP connection

Add a new CAT connection and set the type to TCP. Set the port to 60000. RimuCAT will begin listening on that port for incoming connections from WSJT-X.

Ready for WSJT-X

With the TCP listener active, WSJT-X can connect to localhost:60000 to read frequency and mode, and to key PTT when transmitting.

RimuCAT with a TCP CAT connection configured on port 60000 — RimuCAT with a TCP CAT connection active on port 60000, ready for WSJT-X to connect.

RimuCAT showing an established connection from WSJT-X — RimuCAT showing an active connection from WSJT-X after a successful Test CAT.

Step 4 — WSJT-X Radio Settings

Open WSJT-X and configure the Radio tab to connect to RimuCAT over the TCP port. Use the FlexRadio 6xxx rig type so WSJT-X uses the correct command set.

9. Rig: FlexRadio 6xxx

In WSJT-X go to File › Settings › Radio. Set Rig to FlexRadio 6xxx. This tells WSJT-X which command protocol to use when talking to RimuCAT.

10. Network server: localhost:60000

In the Network Server field enter localhost:60000 — the address and port that RimuCAT is listening on.

11–13. PTT, Mode, and Split

Set PTT Method to CAT, Mode to Data/Pkt, and Split Operation to None. Then click Test CAT — the button should turn green to confirm the connection is working.

WSJT-X Radio settings configured for RimuCAT — WSJT-X Radio settings showing FlexRadio 6xxx selected, localhost:60000 as the network server, PTT via CAT, Mode set to Data/Pkt, and Split set to None.

Step 5 — WSJT-X Audio Settings

With the Radio tab configured, move to the Audio tab and select the RimuDAX devices as the soundcard input and output.

15. Open the Audio tab

In WSJT-X Settings, click the Audio tab. The Soundcard section has separate Input and Output drop-down selectors.

16. Input: flex.dax1.rx1

Set the Input field to flex.dax1.rx1. This is the RimuDAX DAX channel 1 receive stream — the audio coming from the radio that WSJT-X will decode.

17. Output: flex.dax.tx

Set the Output field to flex.dax.tx. This routes WSJT-X transmit audio back through RimuDAX to the radio when the software keys PTT.

WSJT-X main window decoding FT8 signals — WSJT-X Audio settings complete — Input set to *flex.dax1.rx1* (step 16) and Output set to *flex.dax.tx* (step 17). WSJT-X is ready to decode and transmit.

Setup checklist

RimuSDR connectedRimuSDR must be connected to the radio and the DAX button active on the slice before starting RimuDAX.
DAX channel set to 1The slice DAX channel selector in RimuSDR must be set to 1 so RimuDAX picks up the correct audio stream.
TX, Mic, RX1 enabledAll three channels must be enabled in RimuDAX. Confirm the RX1 meter is responding to received signals before moving on.
RimuCAT TCP on port 60000RimuCAT must have a TCP listener active on port 60000 before WSJT-X attempts to connect.
Test CAT greenThe Test CAT button in WSJT-X Radio settings must turn green. A failure usually means RimuCAT is not running or the wrong port is entered.
Audio input: flex.dax1.rx1The WSJT-X Audio Input must be set to flex.dax1.rx1 to receive audio from the radio via RimuDAX channel 1.
Audio output: flex.dax.txThe WSJT-X Audio Output must be set to flex.dax.tx to route transmit audio back to the radio through RimuDAX.
Same station throughoutRimuDAX and RimuCAT must both be connected to the same station (radio) as RimuSDR.