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Hackers Jammed Chicago Police Scanners with Internet Classic ‘Chocolate Rain’

10 points by notRobot 6y ago

giancarlostoro 6y ago
Isn't this technically possible by anyone? My understanding from what little I've read on HAM radios is these are frequencies that are just set aside for police, people can technically broadcast to them, it's just the FCC will hunt you down. Nothing overtly special, though I presume regular radios try to block out those frequencies. Any true HAMs care to chime in? I'm more amateur than amateur radio.
- salawat 6y ago
  Not a licensed HAM, but you are correct. Technically the radio waves remain generally useful because we go to such great lengths to minimize incidental noise emission sources. Get enough pissed off people with spark gap transmitters just blasting RF noise on across the relevant frequency band, and you will significantly degrade the capability to separate meaningful signal from all the noise. However, using regular noise (repetitions of a well known signal pattern) is not the best way to go about it, since you can set up signal processing to cancel out any aspects of the signal you can safely predict, making it easier to recover the underlying information. Overlay high intensity more-or-less random noise makes subsequent information extraction difficult, but as far as I'm aware, you can also still potentially scrounge signal by looking for improbably regular variations against the background noise. So as long as you agree to certain signaling conventions out-of-band, you still maintain some ability to communicate/signal. The ideal jamming setup is a combination of the two. Seed false instances of communique you expect your opponent to send, and swamp the channel with high intensity random noise. Long tangent short, the radio waves as a useful communication mechanism are a byproduct of multiple layers of gentleman's agreement and only really enforcible if the majority of people do not become capable of organizing such that malicious actors are the norm rather than the exception. This is why licensure is such a big deal as a control construct. If you can keep the unlicensed afraid to emit on penalty of prosecution, then you significantly decrease your policed population to more compliant license holders (they got the license after all), and what non-compliant folks are still undeterred by the thought of flaunting the law. You can look at it from the other way that most people are naturally not criminal hooligans; however, as I've gotten older I've come to realize that lack of hooliganism is contingent on the abscence of widespread civil unrest. There comes a point where collective jimmies have been rustled where the threshold to act ends up a great deal lower. Still not seeing that being realistic in terms of outcome with current events; but I've been wrong before.
- chkaloon 6y ago
  Shorter answer - yes. Some Ham radios won't transmit by default on those frequencies, but it typically can be overridden. And yes, it goes against the rules of your license, including the playing of music over the air.
RickJWagner 6y ago
Incredibly stupid. Police are there to serve, to rescue, and to protect. (Yes, yes. There are some bad ones.) What if there was a domestic abuse situation? Couldn't reach the cops. How about a group of racists beating a minority victim? Couldn't reach the cops. A break-in in a black neighborhood? Couldn't reach the cops. etc, etc, etc. This was childish. And stupid.

10 points by notRobot 6y ago

Isn't this technically possible by anyone? My understanding from what little I've read on HAM radios is these are frequencies that are just set aside for police, people can technically broadcast to them, it's just the FCC will hunt you down. Nothing overtly special, though I presume regular radios try to block out those frequencies. Any true HAMs care to chime in? I'm more amateur than amateur radio.

salawat 6y ago
Not a licensed HAM, but you are correct. Technically the radio waves remain generally useful because we go to such great lengths to minimize incidental noise emission sources. Get enough pissed off people with spark gap transmitters just blasting RF noise on across the relevant frequency band, and you will significantly degrade the capability to separate meaningful signal from all the noise. However, using regular noise (repetitions of a well known signal pattern) is not the best way to go about it, since you can set up signal processing to cancel out any aspects of the signal you can safely predict, making it easier to recover the underlying information. Overlay high intensity more-or-less random noise makes subsequent information extraction difficult, but as far as I'm aware, you can also still potentially scrounge signal by looking for improbably regular variations against the background noise. So as long as you agree to certain signaling conventions out-of-band, you still maintain some ability to communicate/signal. The ideal jamming setup is a combination of the two. Seed false instances of communique you expect your opponent to send, and swamp the channel with high intensity random noise. Long tangent short, the radio waves as a useful communication mechanism are a byproduct of multiple layers of gentleman's agreement and only really enforcible if the majority of people do not become capable of organizing such that malicious actors are the norm rather than the exception. This is why licensure is such a big deal as a control construct. If you can keep the unlicensed afraid to emit on penalty of prosecution, then you significantly decrease your policed population to more compliant license holders (they got the license after all), and what non-compliant folks are still undeterred by the thought of flaunting the law. You can look at it from the other way that most people are naturally not criminal hooligans; however, as I've gotten older I've come to realize that lack of hooliganism is contingent on the abscence of widespread civil unrest. There comes a point where collective jimmies have been rustled where the threshold to act ends up a great deal lower. Still not seeing that being realistic in terms of outcome with current events; but I've been wrong before.
chkaloon 6y ago
Shorter answer - yes. Some Ham radios won't transmit by default on those frequencies, but it typically can be overridden. And yes, it goes against the rules of your license, including the playing of music over the air.

RickJWagner 6y ago

Incredibly stupid. Police are there to serve, to rescue, and to protect. (Yes, yes. There are some bad ones.) What if there was a domestic abuse situation? Couldn't reach the cops. How about a group of racists beating a minority victim? Couldn't reach the cops. A break-in in a black neighborhood? Couldn't reach the cops. etc, etc, etc. This was childish. And stupid.