MQTT Applet

The MQTT applet integrates AetherSDR with a station MQTT broker: publish canned messages with user-editable buttons, monitor incoming messages, and overlay topic values on the panadapter.

Open MQTT settings from the applet

Open the MQTT Settings dialog from the MQTT applet to configure broker connection, subscriptions, and publish button settings.

Before you start

• The MQTT applet must be visible. Toggle it with the MQTT tray button on the right sidebar.
• The MQTT feature must be compiled in (requires HAVE_MQTT build gate).

Steps

1. In the MQTT applet header, click Settings....
2. The MQTT Settings dialog opens.

What each control does

Control	Behavior	Notes
Settings... button	Opens the MQTT Settings dialog (MqttSettingsDialog) for broker connection, subscriptions, and publish button configuration.	New in v26.5.3. Replaces the inline Host/Port/User/Pass/TLS/Topics fields.
Enable (Off/On)	Toggle button that connects or disconnects from the broker using settings from MqttSettings. Emits connectRequested / disconnectRequested and saves connection enabled state.	Password is loaded from system keychain on first enable. If keychain password is not yet loaded, shows "Waiting for keychain" status.
Publish buttons	Up to 12 push buttons. Click publishes the configured payload to the configured topic via MqttClient::publish.	Only active while connected. Configured via MqttSettingsDialog Publish Buttons tab. Setting key: MqttButtons.
Message log	Displays received messages as "topic: value" lines and transmitted messages as "TX topic: value" lines. Also processes antenna alias updates from MQTT.	Capped to 50 entries.

Indicators

Indicator	States	Meaning
Status label	"Disconnected" (grey), "Connected" (green), or an error message (default color)	Connection state with colour: green when connected, grey when disconnected, default on error.

Message log details

The message log shows both received and transmitted messages:

• Received messages appear as topic: value lines. For example: ant/A: 1
• Transmitted messages appear as TX topic: value lines. For example: TX rotator/preset: QTH

The topic shown is the last segment of the full topic path. For example, if the full topic is flexradio/6804/ant/A, the log displays just ant/A.

The log is capped to the most recent 50 entries.

Related

• Configure broker connection settings (host, port, credentials, TLS)
• Connect to a station MQTT broker
• Enable TLS with a custom CA certificate
• Add or remove custom publish buttons
• Subscribe to MQTT topics and toggle panadapter display
• Overlay an MQTT value on the panadapter
• Publish a canned message with a button (e.g. rotator preset)