Yup, that's all fine and dandy and thanks 411 for expanding my knowledge of ILS systems in other parts of the world.
Agent Orange is going up a slightly different path though...
To explain all the legaleese in the documents that you have reproduced...
The ILS signal is subject to interference from anything close to the aerial. To protect the signal from corruption we establish areas around the aerials into which a vehicle may not go without permission from ATC.
It is adjudged that in good weather the extent of these areas is sufficient to protect the signal from significant corruption to allow an aircraft to follow the guidance down to Cat 1 minima. There may also be slight deviations in the signal at greater range, even when the critical area is not being infringed, but in Cat 1 weather this is considered acceptable.
If the weather worsens then a greater protective area comes into force - the Cat 2/3 holds e.t.c. to ensure that the signal is reliable down to Cat 2/3 minima.
This is different again to the promulgated range question posted originally, which refers to the signal in space at the
extent of its range.
All very interesting..or perhaps not! You be the judge?!!
