Could North Koreans get wireless internet through the power grid?

Until I saw this linked at Instapundit, I had no idea that it was possible to plug a router into an electrical socket, tap into the electrical grid, and get wireless internet service in areas where the signal is usually weak. Exploring a bit more, I found this customer review, which gives some idea of the performance capabilities:

I loved my network-able Blue-ray player I purchased, but I hated the wireless adapter which left me always praying my Netflix or U-tube content would actually play. Same with my networkable TV, I’d always lose the radio or the news. My PS3 online gaming was a joke wirelessly. I dreaded running a network cable from my livingroom into my bedroom. Such a downer for such great products.

However, I found this little device and AMAZINGLY everything works flawlessly! It’s literally plug and play. High-speed networking that’s virtually wireless!!! You need one on your router end to plug “wire” a Cat5/ethernet cable into and one for wherever you want to have a “wired” connection for your equipment. You use a Cat5/ethernet cable to “wire” your components into the Monster PowerNet which is plugged into the wall. No cables between rooms, only between your router to PowerNet which plugs into the outlet and one from your components to the PowerNet 200 or 300.

You may have to reset your components from wireless to wired, but after that, it just works! NO more jagged netflix, waiting for info to load, missed songs or slow online gaming. It actually downloads the best quality off netflix. I’m really happy with this. I’m used to wiring and setting up computers, home theatre, and complicated set-ups. I was really amazed at how easy it was. [link]

Some obvious questions come to mind:

* Would this still work if the power grid isn’t actually carrying juice (see masthead image!), provided the wires aren’t cut?

* Would this system be able to carry a signal that was broadcast from South Korea, or would it be necessary to surreptitiously link into the North Korean power grid?

* Could this same concept could work by tapping into North Korea’s “cable radio” network, by which I refer to the ubiquitous telescreen-style propaganda speakers?

The customer reviews seem favorable. If anyone out there has the technical expertise to explain the potential of this idea, please e-mail me or drop a comment.

5 Responses

  1. Ethernet over power wires over long distance is doable, but you need infrastructure, repeaters, signal boosters, and good quality wiring. Homeplugs are too weak; they can carry a signal within your home circuit, and that’s it. And from what I’ve heard, it’s ridiculously easy to tap into that kind of network, so… I’m sorry. Unless you’re able to install something directly in the substations or any infrastructure nodes, it won’t be doable, and even then, it’s very prone to eavesdropping.

    I remember WiMAX doing something interesting with mesh networking – a multitude of devices communication with each other, so when one drops out, the network remains operational… but these devices are a) much more expensive b) require a power supply.

  2. Well, no. What this device does has nothing to do with wireless internet. What it does is simply use the power lines as cables through which a TCP/IP network signal can be carried. So both ends of whatever you need to connect needs to be connected to the same power circuit. Sorry.

  3. This is essentially BPL (Broadband over Power Lines). Theoretically you don’t need to actually connect into the grid, but practically you would have to. My understanding of the way it works is that it uses the power grid as a shared bus by which the connected nodes (the plug packs) can connect.

    The problem with using this in an underground fashion is that you cannot get these signals to propagate very far. My understanding of grid design is imperfect (I’m only a student EE) but I would guess that it works by sending high frequency (but low amplitude) signals on top of your standard power signals. These seem to be rated at ~100Mbits so the frequency band is going to in the MHz range. The big problem with this is transformers. AC transformers are actually inductive so they will act as a low pass filter and your lovely signals won’t be able to pass through them.

    Since the voltage is converted to 100-240 V RMS at quite a late stage (every street or so) you simply won’t be able to communicate with many people. You could install a repeater at the transformer, but the next voltage level is something like 10 kV RMS, so it’s not something you can give to just anyone. And of course these could be discovered simply by inspecting the transformers. Also it would be very easy to find who was transmitting by simply cutting off access to sections of the grid. If you did a binary search (turn half of the houses off each time) it would only take log_2(n) steps to find someone transmitting (and that’s assuming there was only one person).

    I’m not familiar with the “cable radio” network, but you might be able to communicate further on that. I still think it would be too easy to find people using it though. It’s a pity though as it’s a neat idea in theory :/.

  4. You have to first understand how you connect two devices together so that they can talk to each other. Just like an improperly setup auditorium will cause the microphone and speakers to reverberate, creating that tell-tale scream, or a poorly designed room can make it almost impossible to talk, a poorly designed network can make it impossible to carry useful signals across its wire.

    If you’re not familiar with how wires carry signals, think of how a flute or a saxophone plays a note. There’s certain resonant frequencies that change when you press keys or when the instrument changes its shape. Your ethernet cables are carefully designed to eliminate these frequencies so that all the frequencies needed to transmit ethernet signals won’t be messed with either by canceling them out of resonating with them. That’s also why you can’t have ethernet cables longer than a certain length. (I believe that’s 100′). If you go beyond that length, you’ll start getting weird behavior with certain frequencies.

    The devices that connect to ethernet cables together are carefully designed to not echo the signal back to the other end. There is a circuit placed at the end that will eliminate the echoes and keep the channel clear for actual signals and not noise or echoes or reverberations. Think of someone holding a rope tightly. If you shake one end, the wave travels down and then reflects back. If you let go of the rope and do the same motion again, it will still reflect, albeit in a different way. If you hold the rope in a certain way, when you shake it, you can absorb and cancel out the reflection.

    The power grid is optimized for a certain range of frequencies, frequencies you need to adapt to both to carry power (60 Hz) or to deal with extra-terrestrial noise. They are not optimized to carry internet signals. They could be modified to do so, and the technology exists to do so. However, it would be an expensive project and it may be pointless. With efficient batteries or super-capacitors or some system of power distribution that eliminates wires altogether, it will no longer be able to piggy-back on that free ride.

    Within your own home, a certain segment of your power circuit may be capable of carrying ethernet signals. This is pure luck and chance, and nothing more.

    If North Korea wants to configure their national power grid to carry internet signals, they’re more than welcome to waste what few resources they have to do so. At least it will mean they aren’t building artillery shells and training more spies.

    If you want to infiltrate such a network, it would be trivial. Ethernet at least is shielded properly, both so it’s hard to hear and hard to muck with the signal. Having routers that clean up the signal and eliminate garbage helps. Power networks behave like giant antennas, broadcasting and ready to receive almost anything.

  5. I spoke with Chinese people in Changbai who insisted they communicated daily with Chinese friends right across the river in Hyesan city who had wireless internet via their cell phones. But I think you’re probably onto something different here.