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Radio receivers are not completely passive; they can act as transmitters at the frequency used to generate their intermediate frequency[0][1][2].

[0] https://en.wikipedia.org/wiki/Unintentional_radiator

[1] https://en.wikipedia.org/wiki/Superheterodyne_receiver#Inter...

[2] https://en.wikipedia.org/wiki/Radar_detector_detector



That's neat, and I was aware of the theory, not of the practice.

Is there any reason to believe that a GPS unintentionally radiates more than (say) a walkman that has a radio? or a wristwatch that has a built in radio? Or that it should interfere with plane instruments more than the latter?

I'm not automatically discarding any report of interference, but I suspect a placebo effect is in play here, with people paying 10 times more attention to everything when they expect something should go wrong.


I switched from EE to CS quite early (and then from CS to solo bootstrapped startup), so I can only speculate beyond what I've already posted. I'm inclined to agree with you, though; if TV fiction is the infallible source of knowledge it purports itself to be, then pilots would seem to be among the most suspicious of professions (gremlins?).

I'd like to know what makes avionics so special if it turns out that they are indeed very sensitive. Consumer, automotive, and industrial equipment has to shield against, filter out, and isolate all kinds of noise.


then pilots would seem to be among the most suspicious of professions (gremlins?).

That should be "superstitious," not "suspicious." That post was made from a phone.




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