Actually, the bandwidth of digital, being much narrower then standard analogue police transmissions, extends the range a bit. Its suprising how well in some areas it gets out.
Ducting is a totally different thing. Ductiing is an atmospheric condition where layers of warm moist air trap signal and funnel it over long distances. Mainly VHF and UHF signals are effected by this, as HF wave lengths tend to pass through the warm layers up to the Iospshere where they can bounce back to Earth ( commonly known as 'SKIP' ). Ducting from my experience tends to work only one way ( not sure why ) and only under certain conditions. I get it mainly in the early summer months when it is fairly humid. The weather conditions have to be right of course, it just doesn't happen all the time.
The general range for digital is better then analogue signals ( one reason why they use it ) so with a good beam type antenna, with some gain and directional properties, you should with some luck, and if your in the correct spot, get some Sydney channel from up your way. Mind you your locations would be a huge factor in this. If your not in a high locations, then I doubt you will receive them, even with high gain antennas. Theres just to much terrain blocking the signal between Sydney and Newcastle.
Dave
