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Distress Signal Emitted By Flat-Screen TV
pinqkandi writes "CNN is a running a story on an Oregon college student's flat-screen Toshiba TV which was releasing the 121.5 MHz international distress signal. He was unaware of the issue until local police, search and rescue, and civil air patrol members showed up at his apartment's door. Apparently the signal was strong enough to be picked up by satellite and then routed to the Air Force Rescue Center in Virginia. Quite impressive - luckily Toshiba is offering him a free replacement."
It's well known that certain hardware hacks for Dishnetwork receivers emit this same frequency.
What a coincidence that a college student (no money) would be doing something technical (education) to get TV for free.
If you could be told what you can see or read, then it follows that you could be told what to say or think - BoC
We just spent $10K+ on in-house EMI equipment, to mitigate the costs of having an outside lab help with troubleshooting.
You have to do it if you make any kind of electronics, but it's a big burden for small manufacturers.
It'd be nice to have the choice of saying "this passes" vs "this probably passes". Current FCC/CE regs require everyone to meet the spec, and this is a bit onerous IMHO. It locks some innovative small companies out of the game.
And even more depressing that someone would choose to see the capability of receiving a distress signal as something other than a good thing (TM).
-- "Only two things are infinite, the universe and human stupidity, and I'm not sure about the former." -A.Einstein
i have talked a few times with someone who worked in the TSCM business (surveillance countermeasures). these are the real guys, not the ones you see with the $99 bug detector. the standard range that they now perform sweeps in goes from DC-300 ghz. i was naturally very interested in what they would be looking for above 30ghz and while the person i talked to admitted that he never personally found anything up in those frequencies, it was well known in their community that such devices were known to exist though they would likely be the domain of only the top government agencies. at any rate the device that he described would look something like the size of a coin and be able to send data in the high ghz range using spread spectrum burst communications directly to an overhead LEO satellite; essentially the ability to bug someone from space using areas of the spectrum that most would never look at and even if they did would likely never actually "see' the transmission unless they were lucky enough to see it transmitting and then only if they were knowledgable enough to recognize the signal from the surrounding noise. scary, huh...
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It was really funny to watch them play DVDs to test out the screen because they would always have the "this video not meant for public viewing" warning before broadcasting it out to the entire south side of Fayetteville. :)
There are two types of people: those prepared for the zombie apocalypse and those who will be eaten.
Hardly. Hams have talked around the world on low power battery radios (although not on this frequency range). It's not that suprising that something plugged into AC power was able to get a signal to a receiver in straight line of sight, even if it was a malfunction. And the receivers are designed to pick up weak signals, there are even watches made that can send the emergency signal (and note that they don't have an external antenna, which at this frequency should be quite large!) Now think that a TV might be attached to an antenna of the proper size for this frequency (it's between TV channels 6 and 7 and just a little above the FM broadcast band). Which is more amazing, that a small watch can get the signal to the satellite, or a TV plugged into the wall with a full size antenna might have a signal that gets out?
I'm an American. I love this country and the freedoms that we used to have.
And, if it is a "Class A" device, the manufacturer warrants that it will not interfere in a residential environment. (Though, many electronic devices sold for residential use are "Class B", requiring the operator to take corrective action if they interfere, and letting the manufacturer off the hook. Yes, this is a simplification)
I stand by my position: the manufacturer should be liable by virtue of their likely warranty that this won't happen. Yes, even if people die, because the device is operated. (And the manufacturer should be held accountable for the resulting wrongful deaths.)
If this were not the case, the manufacturer could just "walk away" from the defective unit, leaving the purchaser with a $5k-$15k television that they can't watch -- it still performs as a TV set, after all, and isn't "defective" with regard to it's primary functionality.
What should happen is that Toshiba should immediately come to terms to compensate the owner for the inconvenience in exchange for an agreement to not operate the set until a replacement is delivered. A rational settlement would be the cost to Toshiba if they had to compensate those expected to suffer because of the continuous operation of the set. So, if there was an expected 0.1% chance of $100,000,000 wrongful death suits, Toshiba should offer $100,000 and a repaired or replaced set in exchange for an agreement to not operate the defective one.
The simple replacement of the set is, IMHO, insufficient.
You could've hired me.
IIRC, the FCC had to threaten the cable operators with "unfortunate consequences" if they didn't fix their leaky systems. My local cable company started using quad-shielded coax and quality connectors instead of the cheap crap that they used to use. They also replaced a lot of their distribution plant with new equipment.
Mea navis aericumbens anguillis abundat
I am not sure if you have ever listened to marine radio near an ocean, but just from my time near the water and listening in, the US Coast Guard has about 10 ELT (121.5MHz) distress signal activations per day, per Coast Guard Group (IE, San Diego Group, Los Angeles Group, etc). They send someone to investigate each one, eventually, and they are all nearly accidental or malicous trips, not real emergencies. It has almost reached the point of too many cries of wolf.
Nick
Butte County Search & Rescue
What makes 406Mhz better than 243Mhz or 121.5Mhz?
The new systems cost thousands of dollars compared to the $50 for the old style transmitters and the new ones aren't selling well. The 121.5 systems are still outselling the new ones even though every boat dealer explains it won't work in a few years. The big problem with 121.5 is they never took the easy route which is to interrupt the carrier every few seconds with a fast cut out circuit and put some detectors on the GPS sats. That would give about 1000 meters of accuracy on the 1st signal and a bit of processing could reduce that to 100 meters which is as good as the new system in most cases and the transmitters would still only be about $50.
121.5 is very well monitored. For one thing almost any aircraft that has a radio that its not using for something else will probably have it on the guard frequency. This is a post 9/11 thing for the most part but a good one. IF you do broadcast on 121.5 every airliner up at 35,000 ft within a few hundred miles may hear you. One of them will relay your message to someone who can help you. Thats a very good thing!
On the minus side sometimes a pilot will broadcast on 121.5 becuase he thought he was trasnmitting on the other radio. (Been there, done that)
Erlang Developer and podcaster
You're only "modulating" at most a few hundred volts for horizontal sweep. It's probably the 30 or so kV for the CRT that comes from the flyback driven by the sweep B+ that had the harmonic and after a year one of the filtering components went wonky.
I see even classic Slashdot is now pretty much unusable on dial up anymore.
"This is where the problem lies. 121.5 MHz divided by 7722 is exactly the same frequency as the horizontal in an NTSC color video signal. The 7722nd harmonic shouldn't really be that strong, right?"
No, In this instance.. the TV set in question is radiating a strong Tempest radiation signal which happens to be at 121.5 MHz.
TV set's are for the most part,aregiant RF amps. Amplifying a video signal until it reaches the phosphors in picture tube, where some of that RF energy gets converted into visible light. All it takes is a tiny fraction(0.1%) of the TV set's overall power(120W) consumption to leak out and it can cause problems like the one described in this article.
IE. The rise/fall time of the picture tube electron gun amp(s) happen to have some component(~4.115ns) which emits a strong 121.5 MHz signal.
In the UK I had a colleague who had Sky 1 overlaying BBC2's transmission. Turned out to be a neighbour had fitted an arial booster so wrongly that they were actually broadcasting their cable signal out of the rooftop ariel.
"The Minions of Satan, I mean Time-Warner Cable"
I'm not directed this to you, so please don't take offense. But its comments like these that I hear often that basically state that cable companies are evil and greedy. I'm not saying you're saying this, but for the most part that's the kind of flak I hear about TWC.
What most people don't realize is that paying for the fiber and coax, installing it yourself, and maintaining it costs major money. And trust me when I say Mother Nature causes havoc on our network (slow modems, disconnects, poor reception, macro blocking = very irate customers). Also, TWC does NOT make money on TV stations. Where we do make our bread and butter is on the recording features and on-demand access, but also on the Road Runner subscriptions. Other then that, your local cable company in large cities are nothing more then a conduit for capturing content from satellite and piping it through your home. Also, lets not forget the employee and leased equipment expenses as well that customers are having to pay.
I'm not saying TWC isn't a profitable business, because it is. But it's not like we are making hand-over-fist either. There is competition in Austin, and we know it....which is a good thing for the customer as a whole including myself. But please, would people stop this 1980s concept of cable companies being a monopoly!
Life is not for the lazy.
This sort of thing is quite common.
One of my old friends came home to finding his home in a mess after local authorities gained entry to investigate a signal causing interference with a local airport about 3 miles from him.
The issue ended up being a problem with his cable box, which they had figured out before he even arrived.
When tuning along the dial, these signals can be heard at specific intervals. The interval spacing is the fundamental frequency. Each point is a harmonic. In this case it does not "just happen" to be at 121.5 MHz ... it is at 121.5 for a reason, and that is because the 7722nd harmonic of the horizontal sweep frequency is 121.5 MHz.
Which harmonics are stronger does depend on the waveform of the involved signal. A sawtooth is going to have a fast rise and slow decay. And that fast rise time can favor those harmonics that happen to have intervals around where harmonics of a waveform which had both fast rise and fast decay with the same time interval would show up (a higher frequency and this a larger spacing).
now we need to go OSS in diesel cars
> It turns out it got stuck on the Lifetime
> network, so it really was in a state of
> distress.
I had a TV (also by Toshiba, coincidently) that would crash when it showed the local community channel. When that happened, it did not accept any key presses on the remote or on the TV set itself, so I couldn't change the channel anymore.
Basically, my TV forced me to watch the horrible Hamburg community channel.
I complained to Toshiba and it turned out that this channel aired a non-standard Teletext that had the ability crash this particular TV's teletext decoder.
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You may like my a cappella music
"I had a TV (also by Toshiba, coincidently) that would crash when it showed the local community channel."
My TV (a Panasonic) has a similar problem with DVB (i.e. terestrial digital tv) in the UK. It will sometimes lock-up and I have to power it off completely in order to get it to work. I presume it's either due to poor transmission error handling or bad coding when handling the interactive menus that can be broadcast with DVB.
And even more depressing that someone would choose to see the capability of receiving a distress signal as something other than a good thing (TM).
This is /. I've seen people argue in favor of getting rid of 911 because they don't think they should have to pay for something they rarely use when the injured person/person being raped/person reporting a lost child could just as easily look up the seven digit number for the local authorities. I mean gosh that E-911 charge on my last bill was like $1.49.
Nobody ever said people were logical. Politics and human nature aside I want to know how powerful of a signal this thing was putting off -- what kind of receive gain do you suppose those satellites have?
I want peace on earth and goodwill toward man.
We are the United States Government! We don't do that sort of thing.
Why did they expect to find a boat/plane in a apartment building?
Boats can be hauled by trailters to various places, including parking lots. Somebody working on their boat in the parking lot could accidentally set off the emergency beacon. Airplanes can and do crash, although crashing near an apartment complex without being noticed might be a bit of a stretch.
At the point the signal is localized to an apartment building, its probably pretty clear that it is not an intentional distress signal (although I suppose somebody could have been kidnapped and found an emergency beacon sitting in the kidnapper's closet...). They still need to find and disable whatever is creating the signal, though, to avoid interfearing with a real distress signal in the future.
Come test your mettle in the world of Alter Aeon!
And how is this thing the size of a coin going to generate enough power at >100 GHz to achieve communication with a satellite? Sounds kind of sketchy to me.
If you're gonna whoop ass you need some good ass whooping tools. As a child of 'duck and cover', shit like this isn't scary at all.
When I want to 'bug' someone, wireless is last on the list.
1)just sidle up and listen in
2)hire someone who is a confidant of the person you want info from
3)hire someone who works for the person you want information from and is privy to it.
In industrial espionage, the easiest way to get information is to entrap a worker by paying him some seemingly large sum for some seemingly trivial bit of information. From this point on, the pay goes down and the quality of the info goes up as you've now got the stick (loss of job and reputation plus possible criminal prosecution) as well as the carrot.
Also, SOP for FBI in gathering personal information that would normaly be denied to them by privacy act(s).
In college, I was able to talk with Cosmonauts on space station MIR on the 144 MHz amateur radio band with a 1-watt hand-held radio, and that was using FM.
I was recently given a TV by a friend, who had upgraded hers.
I very rarely watch tv, as I find few shows are a reasonable quality. When I do watch TV, the new tv occasionally crashes. When it crashes, it simply switches off, and won't restart for long periods of time (even after unplugging for several minutes). I wonder if it's a software thing?
Are TV's really this prone to poor programming practices?
It sure would be interesting to know why the TV in the article was emitting that frequency... an extra solder bridge? Poor programming? Malfunctioning display?
I guess the picture was still fine, or the owner would have returned it earlier, right?
How many other domestic devices that are FCC compliant, with the little 'rf safe' type stickers generate stong RF like this? I've often wondered about mice and motherboards, because I have occasionally run across a computer where the speakers pick up the digital signal from the encoders in the mice. So when the mouse is moved, you can hear a clicking sound from the speakers.
Isn't spread spectrum or other frequency hopping technology essentially undetectable?
If you are looking at only one frequency, yes. However, as they've been used more, the receivers have kept up. When it was thought up by actress Hedy Lamarr, it would have been quite effective, given the tracking devices at the time, to prevent the enemy from finding a sub based on tracking the communications. However, by the time it was in full use, the receivers and trackers both advanced to where it lost this advantage. It did gain a security-through-obscurity benefit in that if you didn't know where to look next, you wouldn't be able to understand the communications, even if you could track it.
I thought the idea was that if you did spread-spectrum right it just looks like noise... isn't that why they invented it? How could anyone detect that just by sniffing?
It doesn't work like that in the real world. If you turn on and off the communications, someone will see the noise floor change. If you leave it on all the time, the noise can be tracked to you (even noise has an origin that can be tracked), but no one will see the noise floor change. So, you have to have a few dB at least above the regular noise for a good signal, so it is detectable. And even if it looks like noise, someone can track where noise is coming from, so it isn't safe.
Learn to love Alaska
Look, no one has ever said that shows like O'Reilly aren't biased. He's a political commentator, not a news anchor. By definition, you are going to get his opinion, not necessarily facts.
You are confusing this sort of programming with regular news and anchoring, something that most networks try to seperate, but only Fox News succeeds in doing. Does anyone remember Peter Jennings remarks on the morning of 9/11? There is your bias.. straight from the news desk.