Mqtt via RF?

Might be a stupid question but I dont get it. I use the latest prebuilt sdcard image. I open ipadress:1880 and find Node Red. Here I add a Inject-node that injects a timestamp and connects it to a Mqtt-output that is configured to connect to Emoncms’s Mqtt-broker. I then use an app in my mobile phone and connect to the Mqtt-topic. This works well and the mobile app shows the timestamp from Emoncms.
But this is via Wifi. Are the Mqtt-message also sent via the Emonpi? Can I use a device with an Arduino and a RFM12b to get the timestamp or do I have to use a Wifi-connected device?

MQTT protocol is layed on TCP. You need a TCP network device to connect to an MQTT server.

Recommend using an ESP8266, lots of wifi MQTT examples. Easiest way is using Arduino IDE to upload to the ESP8266

Yes I use Esp8266/Arduino IDE in other projects, was experimenting with esp8266 and Mqtt earlier today. But I have a clock I built some years ago that got the current time from Emoncms and Packet Generator. Now I’ve upgraded to the latest Emoncms and PG is dead. And so are my clock.

Ah, were you picking up the time over the RFM12B radio network!
EmonCMS transmits the time to the EmonGLCD modules, presumably you were using that?
Have you added the “interval=300” into the runtimesettings in Emonhub.conf?