Below are some screenshots from 50.281 VK4RHT Beacon
and the VK4RTL Beacon if only some operators in the north of the state
would get on even if there was no tropo you could easily make FSK441, ISCAT
Contacts with the length of these pings and how frequent they are.
The signal on the left side is VK4RHT
Strange signal on 50.271???