Use mosquitto_sub in a shell window to subscribe to your weewx/loop topic and see what it emits. It might be a few minutes before you see anything.
# mosquitto_sub -h localhost -u usr -P pwd -t weewx/loop -- You received this message because you are subscribed to the Google Groups "weewx-user" group. To unsubscribe from this group and stop receiving emails from it, send an email to weewx-user+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/weewx-user/fd7605c5-e299-41e9-bb89-3fcf4df3e586n%40googlegroups.com.
