Antenna height - licence exempt frequency regulations

[Broadcom]

The Radio Frequency Spectrum Regulations of 31 March 2011 state:

Annexure B - Apparatus exempt from radio frequency spectrum licenses
...
The antenna of the RADIO APPARATUS must not be higher or above average ground level
than the lowest point of the place where the RADIO APPARATUS operates effectively
...

What does this mean??
For example, if I want to provide WiFi to two towns, one on either side of a high mountain, I can put the transmitter on the very top of the mountain because that is the only place where it operates effectively? What about the 'average ground level' part?

 

[InTheCube]

Find the lowest point where it will operate effectively. Do not go higher than this. That's the way I read it.

Seems to be a pretty pointless clause, as it leaves it open for you to decide what is effective.

 

[Broadcom]

Thanks, it does look a bit pointless.

I was hoping Dominic would be able to clarify WAPAs take on this clause.