I am surprised the Aussie's haven't been on here reporting some of their loggings. I have heard reports in that past that they can do US stations occasionally - of course they would not be regular daytime stations, and at least part of the signal path would be over darkness.
DXing the US and the Western Hemisphere became very easy for those in Australia and New Zealand when Asia went to 9 kHz allocations.
Before that, relatively clear frequencies in the 50's and 60's permitted many loggings. Some DXers there who were active in those years had upwards of 1000 North American loggings, and they often heard radio club DX programs and Frequency Checks.
Similarly, in the 50's and 60's when US stations for the most part signed off at Midnight on Sunday for maintenance, Australian and New Zealand stations could be heard in the eastern US. The difference was that Australia and New Zealand had, combined, just upwards or a hundred stations while North America had thousands.