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.
I 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.
I'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.
Looks 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.
The 50Ω to 75Ω mismatch loss doesn't make a big difference in practice. The cable loss on the other hand...
If you have 60 foot of RG6 you would have 6 dB of loss at 2500 MHz[1]. That is a factor of 4. So you would only have a quarter of the normal signal and output power.
If you use a splitter you have to take that loss into account as well.
OK sure, but putting my access point six feet from my laptop (as it is right now) gives about -40dBm from what I think is 100mW of power and that's regarded as a pretty excellent signal strength.
So if we're starting from a place where -60dB is "excellent" then we probably don't care about 6dB of losses so much.
Actually, the loss can be useful, I wouldn't want to inject the full output power of the transmitter into a receiver... ok it's maybe just 100 mW but still... that's not the power level a receiver expects to get from an antenna.
Yes. 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.
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.
For 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
Even 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.
If 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.
Every coax system in every house I've ever seen (in the US) has been a mishmash of cables and splitters of random length and quality, usually with unterminated branches.
That means absolutely horrid performance at RF frequencies. Cable TV is mostly okay with this poor quality, you can still get a picture from the bad signal, but it might be fuzzy or dark. I can't imagine wifi would work at all under those conditions. You'd get reflections with random phase offset, and it'd probably totally destroy the signal.
What you want is probably possible, but it would require a dedicated line to each terminal run back to a central location with no splitters. At that point, you're just running worse ethernet with extra steps.
I 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...
I 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.
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0. https://www.amazon.com/Hitron-Ethernet-existing-Backbone-Str...
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.
If you have 60 foot of RG6 you would have 6 dB of loss at 2500 MHz[1]. That is a factor of 4. So you would only have a quarter of the normal signal and output power.
If you use a splitter you have to take that loss into account as well.
[1] https://www.net-comber.com/cable-loss.html
So if we're starting from a place where -60dB is "excellent" then we probably don't care about 6dB of losses so much.
2.4GHz is low frequency?
I’d love to read more about deployments like this in the wild and how they work.
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.
That means absolutely horrid performance at RF frequencies. Cable TV is mostly okay with this poor quality, you can still get a picture from the bad signal, but it might be fuzzy or dark. I can't imagine wifi would work at all under those conditions. You'd get reflections with random phase offset, and it'd probably totally destroy the signal.
What you want is probably possible, but it would require a dedicated line to each terminal run back to a central location with no splitters. At that point, you're just running worse ethernet with extra steps.
Deleted Comment
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...