Powerlines and broadband

Factual Questions
1

Recently I ordered a set of powerline adapters for my home network. Basically, you plug one into an outlet room then plug the modem into the phoneline and the adapter. Then, you plug another adapter into an outlet into another room and plug in a computer (in this case my server) into it through a Cat 5 cable.

This was just an experiment and I purchased the adapters cheaply from Monoprice, but it worked perfectly the first time in an apartment building with decades-old wiring (I was expecting lots of problems).

So, my question is: Why is using powerlines NOT the answer, or at least part of an answer, to rural broadband? It seems pretty simple to me.

Bob

2

For starters, you’re probably giving the entire complex free internet and access to your computers (if someone else knew you had it and got an adapter as well). I wonder how far back they can backfeed? A certain amount of feet? As far back as the first step down transformer? Farther?

Beyond that, I have to assume they don’t work as well as just wiring the house with ethernet. You’re right, they really never did catch on.

3

It’s an engineering problem. Transmitting wide-bandwidth signals over power lines is hard enough in a house, but many orders of magnitude harder over miles of high-tension power lines. That said, there has been some progress in this area. As an example: http://www.teammidwest.com/bpl.aspx

4

it causes radio interference to all kinds of devices. when using that over a power grid it brings radio noise to where that grid goes.

5

Previous discussion from 6-7 years back. There was a fair amount of interest in it then:

6

It won’t propagate beyond a transformer. That’s one of the technical issues for BPL - you have to do something to bypass the step down transformer out on the pole to get the broadband signal into the house.

The homeplug standard provides for encryption passwords to address the issue of access by anybody at a power receptacle on your side of the transformer.

What probably largely killed the powerline adapter home network was the popularity of wireless routers, which also have to be secured to prevent access by your neighbors.

7

The power company does sometimes use power lines to transmit data from one place to another (ETA - for their own use, not general purpose data that you could have access to). Your experiment worked fine for you, but transmitting data over power lines can cause interference to other things on those lines. You can get noise in your stereo or TV, for example. You may have been annoying the heck out of one of your neighbors in the apartment building and not known it, and they likely would have had no idea where the interference was coming from.

When the power company sends data across its lines, it filters that data off of the lines before it gets to the customers. That is some extra equipment that would have to be installed all over the place.

Transmitting over larger distances also requires special equipment. Those little plug in things will work throughout an apartment building, and in individual homes will probably work between two or three homes, as long as the homes are all fed from the same power transformer. The signals used on those little plug in devices generally will not pass through a transformer though. Those little plug in things will work throughout your apartment building, but probably won’t work between your apartment building and the one next door.

The power company has the same problem. Data signals won’t pass through transformers on the transmission and distribution lines, which adds some expense to add special equipment to re-transmit the signals around every transformer.

High voltage lines also tend to be electrically a bit noisy, which makes it harder to send data signals down them as these signals have to fight more interference.

All of these problems are solvable, but they cost money to solve, and then the power company just ends up competing with cable, dsl, satellite, and fiber optic systems. There are new wireless systems which are reaching out to rural customers and are very cost effective. You also have to remember that there aren’t a whole lot of rural customers out there who are going to cover the costs for all of the infra-structure that you want to put into the system.

It’s a tough business, and it is fairly easy to see why the power companies don’t want to get into it. They would have limited bandwidth due to the fact that their lines aren’t designed for data transmission, a lot of costs to get into the business, and in many areas they would face competition from folks whose primary business is networking (compared to the power company, whose expertise is in delivering power to your door, not networking). Then you’d have to add high end equipment (basically to create a network backbone) throughout the power company. Just transmitting signals from here to there isn’t enough. Your gear on either side of the line has to handle the thousands of customers whose packets would be routed through that line.

8

It does have the capability of encrypting the signal along with software to set it up on the two adapters. I guess I should try another experiment too, with a friend in the complex to see if he can receive my signal.

Bob

9

A fairly recent Tom’s Hardware test on powerline networking:

Their benchmarks show it coming in far below 802.11n wireless, also below 802.11g, which they didn’t test.

I just don’t see an advantage over a wireless network unless you have some situation where a wireless router can’t reach everywhere in your house. Why did you choose to do this instead of just buying a cheap 802.11g router? Simple curiosity?

10

I did this primarily because I am running both a server (which I wanted to be in a remote room) and a desktop and I did not want the desktop to have to have a fixed IP address rather than obtaining one from DHCP through wireless and I did not want to run a cable through the walls (another option).

Bob