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The FCC used to have specialty cars with spectrum analyzers and complex directional antennas built into the roof to quickly triangulate rogue signals. Not sure
by geerlingguy 4y ago
The FCC used to have specialty cars with spectrum analyzers and complex directional antennas built into the roof to quickly triangulate rogue signals.
Not sure if that's still done these days but I'm sure with GPS receivers and a couple mobile units, a position could be pinpointed very quickly.
- livueta 4y agoFun fact about modern radio direction-finding techniques: you don't need directional antennas, just an array of antennas you can observe phase differences across. It works shockingly well. https://www.sciencedirect.com/science/article/pii/S1877050918320416 https://www.sciencedirect.com/science/article/pii/S187705091...
- viraptor 4y agoThat's got some usual Nyquist limitations, right? For high enough freqs you'll be able to identify the plane, but the direction will potentially alias?
- red-iron-pine 4y agoIt took em a lot longer than 1 hour, but yeah they definitely show up. "We only ask once"
- anthomtb 4y agoIf you infringe on a mobile carrier’s spectrum, for which they have paid a handsome dollar, you can expect to find a man with a Yagi antenna and frequency analyzer in your backyard within a couple hours.
- tjohns 4y agoRelated, the FCC still maintains a network of monitoring stations around the US. Back in the day they were manned, now they're automated and remotely controlled. There's a list of monitoring stations here: https://www.mdarc.org/regulations/fcc-monitoring-stations https://www.mdarc.org/regulations/fcc-monitoring-stations (And yes, GPS-linked direction finding units are definitely a thing that can be purchased commercially. They're big in the amateur radio world for "fox hunts" - competitions to try and find hidden radio transmitters.)