Originally Posted by
SonicFlyer
Tech question...
Do the rad alts encode a specific signature into their transmissions so that when they receive a signal back, even if on the same freq, it will not get accepted, processed, and counted unless it has the embedded code in it, so as to prevent other signals from interfering? Kind of like a watermark for radio signals.
I'm pretty sure they do not, their actual functionality depends on waveform and frequency shifting so it would be hard to overlay encoding on top of that.
RADALTS on the same airframe use a frequency offset. De-confliction between aircraft is apparently just based on distance, ie two planes will not be over the MM at the same time, and unrestricted parallel approaches require at least several thousand feet of offset.
Lot's of technical reading here...
https://www.google.com/url?sa=t&rct=...npGZmHndfU2fdZ
This Honeywell guy's analysis seems to indicate that an individual cell phone in the wrong place at the wrong time might have the power to interfere... he says 10mW, and the phones themselves can put out more than that.