10 ms·
Wi-Fi over Coaxial (2006)
- xen2xen1 4y agoThat's awesome, I'll have to remember that.
- wisefoolkp 4y agoLink is down
- terminalcommand 4y agohttp://web.archive.org/web/20230406012717/https://wifiovercoax.mcleodnet.com/ http://web.archive.org/web/20230406012717/https://wifioverco...
- acuozzo 4y agoPerhaps because the link was running over coaxial?
- patrakov 4y ago(2006)
- pshirshov 4y agoThere are MOCA modems for that.
- micheljansen 4y agoThere are now. They would have been very rare back in 2006.
- pshirshov 4y agoI mean that I won't advise to repeat this hack in our days. From what I understand, MoCA would be faster and more reliable. Maybe it would also be safer.
- ale42 4y agoLooks like it works, but I think that it is far from being optimal. CATV coax usually has an impedance of 75 Ohms, while the antennas of routers (and most RF stuff, except TV) are usually 50 Ohm. If impedance was right, the signal would probably be able to go much further.
- Gordonjcp 4y agoAt the very low frequencies involved, the impedance mismatch is pretty much negligible.
- MisterTea 4y ago> At the very low frequencies involved, 2.4GHz is low frequency?
- NovemberWhiskey 4y agoIf you're a ham-radio operator, no; if you're a mmWave engineer, yes.
- MisterTea 4y agoYou know I was originally going to be snarky and answer "low frequency? You must be a microwave engineer."
- nomel 4y agoCorrect me if I'm wrong, but this where you build circuits with parasitics, correct? ;)
- Gordonjcp 4y ago73 de MM0YEQ, I love working on stuff where a snipped-off bit of component lead is a "random long wire" antenna.
- Gordonjcp 4y agoIt's practically audio rate. It's not radio until you need to use jeweller's rouge to tune the aerial.
- b0z0z0 4y agoRun pingtools on android and pick a WiFi channel that isn't being used in the proximity.
- ryan-c 4y agoIn 2006, it would have been netstumbler or kismet, and on 2.4GHz they're all in use in proximity.
- nomel 4y agoIn all of my WiFi routers, even the cheapest one, this is done automatically.
- b0z0z0 4y agoI was at a big corp a few years ago, none of our expensive Meraki was doing it automatically, which was ironic. I like visually seeing the bands and choosing one that appears open.
- nomel 4y ago> I like visually seeing the bands and choosing one that appears open. This requires polling, to see if any neighbors have installed new/shifted AP.
- madjam002 4y agoIsn’t this how they do wifi in tunnels and metros? Using coax and “leaky feeders”? I’d love to read more about deployments like this in the wild and how they work.
- fltnlow 4y agoYes. Depending on the frequency(s), the spaces between cuts on the waveguide vary. But it's basically just open space in the cable/waveguide letting frequency leakage. Coax or waveguide (hollow cabling) can be used.
- jiveturkey 4y agoThis project uses leaky feeders? https://en.wikipedia.org/wiki/Leaky_feeder https://en.wikipedia.org/wiki/Leaky_feeder I must have grossly misread TFA. The way I read it, he is just using an existing coax cable as the wifi RF in/out on 2 APs. Exactly as one would use a commercially available MoCA bridge.
- jakedata 4y agoFor houses that have coaxial cable tv runs to many rooms it would be great to find a 75 ohm f-connector wi-fi antenna that you could just screw onto the wall plate. You would need to match impedance with the WiFI device at the other end but the result would be reasonable WiFI in whatever room you want while the ugly blinkenboxen remain in the basement. Rather than use splitters it would be best to use one cable per antenna. Something to ponder while staring at my basement parts bin for sure. edit: https://en.wikipedia.org/wiki/Wi-Fi_over_Coax https://en.wikipedia.org/wiki/Wi-Fi_over_Coax
- deleted 4y ago[deleted]
- tomfanning 4y agoEven ignoring the impedance mismatch, loss in typical 75 ohm coax at 2.4GHz is going to be something like 0.5dB per metre. Far worse again at 5GHz. That's going to add up quickly.
- oakwhiz 4y agoIf nothing else is on the same run, the amount of noise from external sources should be very low, which in many noisy RF environments is fine when you are only going 10-20 meters through a building. The transmit power of a wifi card is going to be way above the amount of losses that would cause issues.
- nomel 4y agoFor comparison, to see if this matters, what's the loss through air?
- Dylan16807 4y agoThe loss from air itself is a tiny fraction of a decibel per kilometer. But using an antenna means you lose 40-48dB in the first meter for 2.4-5GHz. And then you lose 6dB for each doubling of distance, so another 12-18dB for 4-8 meters. If you're less than 20 meters from an antenna, not only do you have those massive upfront losses, you still lose more than .5dB for each additional meter of distance. Coax wins in almost every situation.
- terminalcommand 4y agohttp://web.archive.org/web/20230406012717/https://wifiovercoax.mcleodnet.com/ http://web.archive.org/web/20230406012717/https://wifioverco...
- xeromal 4y agoLinus Tech Tips on Youtube does a video on this and it was pretty informative.
- getoffmyyawn 4y agoIf you want something like this today, there are widely available moca devices[0]. I use two pairs in my house and reliably get 1gbit on each run. 0. https://www.amazon.com/Hitron-Ethernet-existing-Backbone-Streaming/dp/B08MQG6T61 https://www.amazon.com/Hitron-Ethernet-existing-Backbone-Str...
- primis 4y agoI've been doing this for years! FYI if you have XFinity or Verizon FiOS you get one end of this for free. All FiOS routers support MoCA, even if you're connected to the ONT with direct attach BaseT (it's used internally for the set top box LAN segment too). Also XFinity Cable modems (at least, the last one I had 2 years ago from them!) supported it too, but not out of the box, it was a hidden option in the settings menu. Depending on the gear, you could get as much as 2.5Gbps through the channels, but beware! just like WiFi, this is shared bandwidth for every device. Its also a bit sensitive to daisy chained coax splitters -- it prefers a flat topopgraphy for best signal performance (though you should really be doing that anyway). Also unlike WiFi, MoCa is really zero config needed past initial enable.
- gorkish 4y agoMoCA 2.5 is 2.5gbps; works great and inexpensive. It's not at all like HomePNA in that it does not shit all over the RF spectrum. Please do not use these powerline bridges; they are awful in all respects and should never have been allowed to be marketed. Also, doing the thing in the article isn't ideal either, though there are always a lot of interesting RF things to try with WiFi. Look into leaky feeders / leaky coax for instance.
- getoffmyyawn 4y agoI do not use powerline bridges. I've had my setup for years and I only get 1gbps because my gear is MoCA 2.0. It has been a truly "set it and forget it" setup for me.
- Arrath 4y agoHuh, good to know! I will keep these in mind when it comes time to replace my parent's ethernet powerline adapters.
- msla 4y agoSoon, they'll discover the advantages of unshielded twisted pair and recapitulate the development of Ethernet up to the 1990s.
- peter_d_sherman 4y agoI like this idea a lot; a) It's highly interesting b) It's something I hadn't ever thought of previously until I read this article; c) In theory this approach is _slightly better_, _a little bit better_, _a step in the right direction_ for local network security -- better than WiFi and slightly better than Unshielded Twisted Pair (i.e., standard Ethernet cables). A perfectly secure point-to-point signal transmission medium (at least as far as the signal goes, not as far as other network components go) would be a medium which is shielded much like a coaxial cable is -- but then highly tested to insure absolutely no signal leak at the frequencies it is going to use... Related observation: Optical cables -- would meet this criteria...