I think Jabawocky raises an interesting point. How long before some whizz-kid in Canberra decides the "within 10 miles" isn't specific enough and decides all aircraft within (say) a 15 mile radius of an NTA must carry radio, and use it?
I recall precisely what an MBZ was, and it doesn't take much to see the new Broadcast Area with a CTAF surrounding an NTA morphing into something very close to what what we used to call an MBZ. (Why is it every time we re-invent the wheel we have to have this lengthy argument about what colour it should be?)
Now, I'm not against change if it improves safety or removes confusion about what the intention of the regulator is. However I am getting fatigued with the continued tweaking of the definition of a volume of air which constitutes a Broadcast Area (and which has a CTAF associated with it, since a CTAF is by definition just a frequency, not the volume of air itself - point acknowledged and noted).
Actually, I am still trying to remember what was wrong with the old CTAF broadcast area's 5 miles and 3000 feet boundaries. It precisely defined a volume of air. You were either in it or you weren't. The old MBZ of 15 miles radius and 5000 feet did likewise. One height, one radius for each volume of air. It wasn't perfect, but it worked pretty well as far as I can recall. The boundaries were even marked with special symbols on the VNC and VTC. That worked too. Not any more. At least we have the radio frequencies on the charts again.
My thanks to Capn Bloggs for the heads-up about Large CTAFs. Being a southern state aviator who has never had the adventure of flying in the far North, I was unaware of these huge areas. Thanks, too, to all who have posted. Your time, input and effort are genuinely appreciated.
I'll grovel through AIP ENR 1.4-7 and try to pick the bones out of it sufficiently to impart the new requirements to any pilots I encounter who may be unaware of it. That's probably just about every pilot who holds any sort of recreational flying certificate, because their respective organisations don't seem to have promulgated anything about this at all. Most eloquent in their silence.
Meanwhile I'll look forward eagerly to the next instalment of the ongoing saga of the new airspace procedures. I don't think we've seen the last of it yet.