According to this study (https://web.stanford.edu/group/scpnt/gpslab/pubs/papers/Liu_...), the Texas spot is the US Military doing aerobatics training, causing the training aircraft to repeatedly report signal loss.

My guess is that the spots in Western Australia are the same thing, given the nearby RAAF training bases.

WA may be the radio quiet zone: https://www.industry.gov.au/science-technology-and-innovatio...

That was my guess too. Apparently Starlink satellites go quiet over the area too but there is still some detectable EMF.

Western Australia could be the ongoing emu war - https://en.wikipedia.org/wiki/Emu_War

I crosschecked with google Maps and I belive the Jindalee Operational Radar Network in Laverton is stationed there. Maybe that has something to with the interference. A 560kw transmitter is no joke.

I guess south-west Texas is most likely also military. E.g. the Naval Air Station Kingsville is not far away.

Huh I had no idea Australia had a big OTH radar network. TIL!

That spot in western Australia is interesting, I was looking at that earlier. My map doesn't show any indication of interference there, in fact from what I can tell there's plenty of evidence of _no_ interference. Eh, there are sometimes analysis or other artifacts, and it can be tricky to try to infer too much from one hex.