External interference
Quote from DingerX:
Or the thing was in the environment, several miles from the threshold, and on the ground, and then you'd have to ask, "Why does this matter again?" I mean, have you driven by an airport and measured the environmental RF noise? You have more cellphones, more bluetooth devices in one area, along with several radar systems and HF/VHF/UHF transmitters, and most of these have a clear line-of-sight to the runways. Heck, I remember being in a bus passing a military airport in Syria where the noise was so bad, the entertainment system speakers started serenading us -- and they were switched off!
(Unquote)
So, while we are exploring this remote posibility of external RFI (or whatever we are going to call it), I wonder if you experts might like to address the specific proposal of what might be capable of doing the business from a range of about 200 - 800 metres.
As it's the early hours, I'm going to indulge my imagination for a few moments, knowing nothing of the subject. Seems to me, the transmission would have to be (a) unusually high power and (b) directional (unlike most of the examples above).
High power from a domestic or mobile power-source would imply split-second pulses; due partly to the constraints of the power source, but also to avoid cooking the antenna?
Directional transmission would require a fairly complex antenna, I presume. This would be bulky and cumbersome to aim at a moving target. But you don't have to move it, because every A/C approaching the duty runway will be at exactly the same height and position as it passes, say, the 2-mile point on the ILS.
That just leaves the problems of choosing the most effective frequency or frequencies (to penetrate shielding, and have a sufficiently adverse effect), and finding/creating the transmitter and antenna. The latter would need to fit in the loft space of an ordinary semi-detached house.
When you have considered this - purely hypothetical - proposal, can you tell us why it couldn't work?