Australian TV Channel Blocks, Bands and Frequencies (plus Band-Pass Filters)
Australian TV Channel Blocks, Bands and Frequencies (plus Band-Pass Filters)
First, here's the table with all the boring text and numbers. I've added colour to spice it up a little bit, but deliberately chose pastel colours because I don't want to overstimulate you.
You can see from the table above that there are five channel planning blocks, each with six channels. That's so that ABC, SBS, the Seven Network, the Nine Network, and Network Ten all have space to broadcast at each location, along with a spare channel. Ostensibly, that spare channel is for community TV, but it could be another commercial broadcaster, emergency broadcasts, or even to help DAB+ spread Australia-wide.
When trying to think about digital TV channel restacking all those years ago, the decision was made to create a shorthand way of talking about groups of channels. The idea was that when you've got multiple TV transmitters/towers that are geographically close and might overlap, you don't want these to be on the same frequencies.
It's also almost equidistant from three TV transmitters:
Seymour - Channels 40-44 on UHF V
Bendigo - Channels 28-33 on UHF IV
Goulburn Valley - Channels 34-38 on UHF IV and UHF V
Or, in Channel Planning Block terms:
Seymour - Block D
Bendigo - Block B
Goulburn Valley - Block C
Extrapolate this across all of Australia, and you've got a quick and easy way to make sure that there are no channel block overlaps. It's the same way you plan out larger WiFi access point systems while dealing with limited 2.4GHz or 5GHz channels, just FYI.
By the way, Colbinabbin is by no means unique in having the potential for overlapping transmitters. Have a look at Newcastle! Given the terrain up there, there's less overlap than you'd think from this image, but I know the TV antenna installers in the area have a lot of rogue signals to deal with.
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