So I was up on Red Hill today as the 70cm net was meant to take place on 434MHz. As I ascended Red Hill I noticed there was a definite oscillation occurring on frequency. 25kHz either side was clear of it, but in general a bit noisy – we eventually moved the net to 433.975MHz.
After the net though I continued to tune around here and generally found there was a lot of noise/interference. I could even receive the local triple j (101.5MHz) on 433.375MHz so I'm not really sure what's happening up on Red Hill.
That said though, VK1FMDP was also receiving a lot of noise up on Mt. Arrawang. Hmmm…
Anyway, here's a recording with the squelch completely open. It goes through 433.975MHz, 434.000MHz and finishes on 434.025MHz.