A couple of years ago, I bought a Devolo dlan 200 AV to extend the internet in our house at the time. It has proven a pretty fine purchase in every house since, including our current casa, which has the broadband router near the dish on the top floor and the extender gives us wifi on the ground floor and in the basement where we work. The NAS is also cabled to the extender downstairs.
All fine and dandy. Except... Quite often the green LED indicator for broadband signal strength turns orange or even red, indicating (as it would) that the speed is decreasing to an almost unusable point.
If I take my ipad upstairs and connect to the router directly, it's fine, with the full 10meg, but for some reason, the powerline connection is up and down like Leicester City. Also, it is definitely the broadband side not the wifi as the connection to the Devolo network remains strong.

There seems to be no correlation with devices connected, as the signal can be weak or strong whether I'm alone in the house or whether MrsC and stepson Minor are using any or all of their half dozen internet-enabled gadgets.

Can any technically minded person suggest any outside cause for this problem? Firmware on the Devolo kit? Other interference from our house or the neighbours on the power circuits? Overheating of the extender?
All ideas welcome, as it is a bloody pain having to lug my laptop up 4 flights of stairs to work when it stops working.
I'd be prepared to consider buying a new extender, if necessary, so suggestions on that front would be welcome too...

Many thanks, as ever...

In the UK the Brown & blue A/C wires are connected to the sockets the SAME way and plugs ONLY fit one way.

Not sure on individual EU nations wiring but I would have thought they too would wire all sockets to a similar standard. Plugs however can be fitted 180 degrees out. Not really a big issue for an appliance but it could be for routing signals.

So, are your plugs both the same way, have you tried fitting one of them the opposite way?

If that doesn't work it might be an idea to go for WiFi repeater / extender rather than power line type?

Or, run cat 5 to another router, if you have a spare.

Powerline networking doesn't actually use a wired connection over the mains between the 2 points, it uses short wave radio, so is susceptible to and produces all manner of radio interference.

You could try different kit but it may just be that there's external interference.

Thanks guys. Bob, I'm not sure if it makes any difference which way round the units are plugged in because much of the time the connection is fine. Similarly, I was worried that having to use UK>Spanish adaptors might cause a problem, but when it works, it is as fast as the connection directly from the router.
I think Graham's interference theory is most likely, but my fear is that the problem may lie with the neighbours; the connection will sometimes drop right away without anyone in our house turning anything electrical on or off. Can you suggest any likely culprits for high interference levels? Laptop (or other) power supplies? TV?, Xbox?

Cordless phones and microwaves can play havoc with WiFi, so not entirely sure if it will be the same for the powerlines

Hmmm. I should try some experiments - turn on the microwave in different parts of the house and see if the signal suffers. Even if it's the neighbours that are causing the issue, it would be good to have an idea of what they are doing to stuff our signal...

It definitely does use the mains wiring.

Can you try different sockets? No idea on Spanish wiring regs etc but ideally you want to find 2 sockets on the same circuit giving you the shortest route.

They use the mains wiring only as an aerial to transmit via short wave radio, powerline adapters will communicate perfectly with no physical connection between them.

Couple of good demo videos here:

www.youtube.com/watch?v=utfUEEhmHYY

www.youtube.com/watch?v=9-Ge61BXsaQ

Good god, that was boring

That's not how they're designed to work though, they are designed to be physically connected. They do not use the mains wiring as an antenna intentionally, it's merely a side effect of sending high frequency signals down unshielded mains cables.

Watch the videos.

There's no radio interference when he uses a normal ethernet network connection and the ethernet cables are no more shielded than the mains wiring, probably even less so.

Also, in this video:

http://www.youtube.com/watch?v=0xAxvJILDIE

he shows a local radio transmission preventing data transfer on the powerline adapters even when they're both connected to the mains wiring as intended.

If the radio transmission and reception of the powerline adapters is purely coincidental and they actually communicate fully over the mains wiring then why does a nearby radio transmission jam the connection and doesn't jam a normal ethernet connection?

Even if this is all just coincidence and bad shielding of cables it shows that the marketing of these adapters as "wired networking" is misleading as no other form of wired networking is susceptible to radio interference like these powerline adapters are.

In reality they are effectively wireless, in that they can clearly communicate wirelessly and are susceptible to wireless (radio) interference.

Cat5e (Normal Ethernet cable) use twisted pairs to eliminate the effects of interference and cross talk, along with differential signals, it's a lot less susceptible to interference than main cabling. The physical properties of the two signals are also different.




You're not comparing apples with apples here though, Powerline adaptors are not simply turning the mains into a cat5 cable Ethernet network, they are taking a normal "Ethernet" signal, doing some clever things with it, putting it onto the mains cable, then decoding it the other side, and turning it back into a normal Ethernet signal that your PC understands.

It's the "doing some clever things" bit that turns your mains cable into an antenna as a side effect. They really aren't designed to be wireless!

According to "How Stuff Works", powerline extenders use Intellon's PowerPacket technology that is based on Orthogonal Freqency-Division Multiplexing.
So that clears that up then.

Benje and Graham, are we all agreed that regardless of whether extenders deliberately use the antenna effect, interference is still my enemy? Or might this debate suddenly open a window of hope whereby if I rub the extender socket with a ripe mango, it will work fine, all the time?

And just to clarify, they use the earth connection only for the network signal. But in my experience, just like broadband, the advertised speeds are rarely attained, some of my 200 Mbps adapters struggle to reach 100. There's a "power packet" utility that tells you the speed that each adapter is achieving, and connecting across different circuits makes a noticeable difference.

Apologies for taking it off topic somewhat. I'd try and ensure they are on the same circuit in your house first. It seems like the router is on the ground floor and the PC on the first? Are all the sockets in the house off one fuse/circuit breaker or are the floors on their own circuit?

I'd be tempted to try different sockets first.

True, but even if you took an old style coaxial (10base2) ethernet cable and cut it half way it wouldn't magically still work via wireless, unlike powerline networking when you disconnect the mains cabling between the adapters.

Powerline networking may not be designed to be wireless but it has all the advantages and disadvantages of wireless and none of the advantages or disadvantages of wired, so for all intents and purposes it may as well be considered wireless.

And for Jim's question, if he was assuming that external interference was unlikely be an issue due to powerline adapters using a "wired" connection (as with a standard wired ethernet system) I'm just pointing out that they are effectively wireless and therefore external interference is likely the source of the problem.

Maybe I should have worded my original post differently to say it was "effectively" wireless.

Wow this post has been busy.

OK, first of all, make sure there are no RCD's on the plugs you are using, also avoid any PSU type adapters on that circuit and if you can, try to make sure the Powerline adapters are not on any trailing sockets. Mobile phone chargers apparently are a major cause of interference.

If the reduction in signal is intermittent then I would suggest something with an electric motor, etc is causing interference, (washing machine, air conditioner etc).

http://www.smallnetbuilder.com/lanwan/la...k-speed?start=1

Both extenders are (deliberately) plugged into individual sockets with nothing else; I have no way to tell if they are on the same circuit, except that for some of the time, it works perfectly, suggesting outside influences at work.

What about this fella ?

^^ Looks promising, they claim it has "excellent" interference immunity, as opposed to "weak" for the powerline adapters.

Do you have decent coax cabling that you could use?

Mores the point is there any scope to actually install an ethernet cable either to the middle floor to relocate the router or install an access point, or from top to bottom (possibly stopping of in the middle).

It seems that you can use the cabling for your TV aerial feed, which would be handy because on the top floor, where our router/modem is located, is also the box for our cable TV. So I could just put the master box in there and the other next to the TV itself 2 floors below. Then I think it would be a case of hooking up another router as a wifi extender.
The problem we have is 2-fold; firstly, we rent the house, so we can't go adding cabling and secondly, our office is in the basement, 4 floors below the router, meaning we'd need a lot of cable if we did go that route. Also awkward is the fact that we need decent broadband on all levels.

I guess that you have tried altering your signal frequency in the router settings. It could be that you and your neighbour are on a similar setting.

Try all the way to the top, and if that doesn't work, all the way to the bottom.

Bob, that's not relevant; the wifi signal from the router itself is fine and the extender is connected via an Ethernet cable. The problem occurs somewhere between the power socket next to the router and the wifi signal dispensed from the other extender plug downstairs in the lounge.

OK, maybe the units are just giving up?

This is almost exactly how my old Belkin router failed. A perfect wifi signal but an intermittent internet connection.

I replaced it with an ASUS and have enjoyed a rock solid connection, and significantly better wifi performance.

That's a good point, Bob. I've been using these units solidly since Jan 2012, which doesn't seem a long time, but possibly they might be on their last legs, hence giving fluctuating performance.

Interim solution; I went round every socket on the bottom 3 floors of the house, plugging in the extender slave plug. The basement is hopeless (1 spur socket daisy chained with about 6 extension cords. Luckily not powering anything bigger than a laptop). The lounge on the ground floor (where I had it plugged in when all this began) is the worst of all, the dining room almost as bad.
However, on the floor above, I can get a decent signal and the broadband strength LED remains green. As the Wifi signal from the extender is pretty good, I can still get a reasonable connection at my desk in the basement and in the lounge. Although the signal is not at Max strength, the broadband is way stronger (6mb instead of barely 1), so it works better, if not exactly rapidly.
It'll have to do until I can find a cheap way of running a better connection...

Jim, is this a 2.4GHz thingy or a 5GHz thingy? (For the wifi bit of it).