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Powerline adapter affecting fibre line speed

BB-8
Hooked
Posts: 5
Registered: 20-07-2017

Powerline adapter affecting fibre line speed

Hi All,

Apologies form the outset for a post that may ramble for a bitSmiley

 

I have just upgraded to F2C broadband and have seen my line speed increase from 17Mbps on ADSL to north of 34Mbps, so needless to say a fantastic improvement.  When I run the speed test via the RJ45 wired devices all seems OK.  When I run the test via a WiFi connected device I was getting no more that 4.5Mbps...not so good.

 

After much head scratching the issue goes away if I switch off my Devolo 500 AVplus (non WiFi version) homeplugs.  This isn't helpful, as the only way I have to reach the Sky box IP connection is using these devices.  I initially thought they were faulty, but after much checking I discovered the following:

  • The issue is specific to one RCD with two rings connected to separate breakers.
  • Each circuit breaker covers two rooms, and in one room if I plug the Devolo in the WiFi speeds are hampered, but in the other room it is fine, but they are on the same breaker.  If I do the same test in the other two rooms (which are on the other breaker) I get the same issue, WiFi hampered in one, but not in the other.
  • Either Devolo will cause the issue (which makes me think it isn't them) and they don't even need to be connected to the router to create the problem.  Just plug into the socket and switch on

Of course if the room where the Devolo had no WiFi impact was the one with the Sky box in then I wouldn't worry, but of course it isn't and whilst they work, the WiFi in the other parts of the house are seriously slowed.

 

I know you will say, why not use a WiFi connection into the Sky box, but the WiFi signal is quite weak in that room and Devolos have historically been the answer.

 

I have never noticed the issue before on ADSL.

I am suspecting I have an electrical wiring issue, but as not breakers or RCDs are tripping it doesn't sound like I have crossed neutrals.

 

Sorry as this post is half about broadband and half electrical.  But I wondered if anyone had ever seen something similar before, or could offer any suggestions as to my issue based on my explanation.

14 REPLIES
Community Veteran
Posts: 4,767
Thanks: 102
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Registered: 14-07-2009

Re: Powerline adapter affecting fibre line speed

If the Devolo devices do not have an adverse effect on an Ethernet connection then they do not affect the fibre line speed.  So what is affected must be the speed of your WiFi connection.  If there were a lot of radio interference going on that might cause a lot of packet loss which would reduce the effective speed of your connection to much less than the nominal speed.  So the Devolo devices are, it seems, behaving like little radio transmitters, possibly acting in conjunction with your mains wiring.    

VileReynard
Seasoned Pro
Posts: 10,646
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Registered: 01-09-2007

Re: Powerline adapter affecting fibre line speed

Replace the Devolo devices & any wi-fi with ethernet cable. It is cheaper and gives a much faster connection.

Superuser
Superuser
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Registered: 10-04-2007

Re: Powerline adapter affecting fibre line speed

Another possibility is local interference caused by the power supply for another device.  E.g. DECT phone; Mobile charger; Radio..............   Some of these units can be very electrically 'noisy'.  I spent ages discovering my poor broadband performance was caused by the Router power supply!

So try switching off other devices and check for improvement.

Community Veteran
Posts: 4,767
Thanks: 102
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Registered: 14-07-2009

Re: Powerline adapter affecting fibre line speed

Whilst it is perfectly possible for radio frequency interference to have a bad effect on the line speed, this will affect all devices whether connected by WiFi or Ethernet.  As noise increases the router will report a much smaller signal to noise ratio and if it drops the connection whilst the RFI is present then the connection will be re-established at a much lower line rate.  I have experienced this problem myself and seen the symptoms.

BUT if the speed of the connection remains the same when the computer is connected via Ethernet then that is not the problem here.  

wisty
Aspiring Pro
Posts: 443
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Registered: 30-07-2007

Re: Powerline adapter affecting fibre line speed

In the switch from ADSL to FTTC did you change the router?

If you did, it might be worth turning off WiFi on the new device, and configuring the old one as a Wireless Access point.

If you still get slow WiFi with that configuration, then it is possible that you have always had the issue, jut not noticed it.

On the other hand I think I agree you might have a wiring problem. Is the second (problematic) room of each pair a true ring (i.e. both "ends" are connected back to the breaker, or are they wired as a long spur off the first room of the pair?

BB-8
Hooked
Posts: 5
Registered: 20-07-2017

Re: Powerline adapter affecting fibre line speed

Hi All,

A big thanks for all your responses.  The initial ring final issue I talked about seems to have gone away, which is good as it didn't really make a lot of sense.  

After more testing it does appear that the only common factor is the Devolo devices themselves.  They only need to plugged into to the mains and switched on to cause the line speed issues, but the oddity is that either device causes the issue, so they are both faulty (which does seem unlikely) or I have simply found an incompatibility when they are used in my set-up.  As the devices are quite old (AVPLUS 500) changing to to a newer version may work.

I can't run Ethernet cable as it will look unsightly and that is not an option.

 

I'll update this thread if new adaptors resolve the issue. 

VileReynard
Seasoned Pro
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Re: Powerline adapter affecting fibre line speed

You realise that buying so-called 500Mbit/sec devices is pointless?

The eventual ethernet connection will run at the best achievable speed of 10 or 100 Mbit/sec.

Of course, these devices will never run at close to 500Mbits in a home setting.

Community Veteran
Posts: 4,767
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Registered: 14-07-2009

Re: Powerline adapter affecting fibre line speed

An alternative to new powerline adaptors might be to use a wireless range extender (with an Ethernet port).  That's not necessarily a better alternative, indeed it might not work at all if the distance is too great, but the technology is different so it might work where powerline adaptors do not.

Community Veteran
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Registered: 14-07-2009

Re: Powerline adapter affecting fibre line speed


VileReynard wrote:

You realise that buying so-called 500Mbit/sec devices is pointless?

The eventual ethernet connection will run at the best achievable speed of 10 or 100 Mbit/sec.

Of course, these devices will never run at close to 500Mbits in a home setting.


I can see that if you using your powerline adaptors with standard Ethernet you will not exceed the Ethernet speed of 100 Mbit/s but what if you use Gigabit Ethernet with powerline adaptors that support this?  Surely you might then do a bit better than 100 Mbit/s?  That's what it says here: http://www.techadvisor.co.uk/feature/network-wifi/what-is-powerline-3491484/ .  Anyway, for most practical purposes the limiting speed is the speed of your internet connection. 

BB-8
Hooked
Posts: 5
Registered: 20-07-2017

Re: Powerline adapter affecting fibre line speed

Hi,

 

Yes thanks, I am fully aware of this.  The Devolos I have were the best to have when I bought them.  I only mention 500 so you knew the model I was referring too.

BB-8
Hooked
Posts: 5
Registered: 20-07-2017

Re: Powerline adapter affecting fibre line speed

Thanks for your advice.

BB-8
Hooked
Posts: 5
Registered: 20-07-2017

Re: Powerline adapter affecting fibre line speed

The Wifi extender maybe an option.  I do have wifi in the next room and the signal is, but I have more than one device with an ethernet port.  However, I have found one with 4 ports and I guess I could connect a hub to an extender with a single ethernet port.

 

Food for though on both the extender and better powerline adaptor (than the ones I currently have).  I may try both of them out and then keep the one that does the better job.

nanotm
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Re: Powerline adapter affecting fibre line speed


BB-8 wrote:

 

 

I can't run Ethernet cable as it will look unsightly and that is not an option.

 

 


you can hide the cable under the floor (or just under the carpet) in the walls/ceiling or just use cheap conduit to keep it out of sight, you don't have to have it visible necessarily

 


ReedRichards wrote:

VileReynard wrote:

You realise that buying so-called 500Mbit/sec devices is pointless?

The eventual ethernet connection will run at the best achievable speed of 10 or 100 Mbit/sec.

Of course, these devices will never run at close to 500Mbits in a home setting.


I can see that if you using your powerline adaptors with standard Ethernet you will not exceed the Ethernet speed of 100 Mbit/s but what if you use Gigabit Ethernet with powerline adaptors that support this?  Surely you might then do a bit better than 100 Mbit/s?  That's what it says here: http://www.techadvisor.co.uk/feature/network-wifi/what-is-powerline-3491484/ .  Anyway, for most practical purposes the limiting speed is the speed of your internet connection. 


only if the power line adaptors are used on the same ring and do not cross the breaker box. and 9 times out of 10 they will default to 10mbps anyway because most companies only put a 10mbps rj45 socket into the plugs......

 

 

just because your paranoid doesn't mean they aren't out to get you
quelquod
Aspiring Pro
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Registered: 31-07-2007

Re: Powerline adapter affecting fibre line speed

I have a ham radio licence and find that Powerline-type devices in general are fairly poor for the amount of RF noise that they generate. Some better than others. I often have to unplug mine when I'm on the air on some bands so it's not too surprising that yours might interfere with your wifi. It's not even necessary for the Powerline to be in the same frequency band as it's quite common for wifi devices not to be resistant enough to stray RF fields. It's all well covered in the approval regulations, but in the interests of cheapness manufacturers tend to infringe these quite a bit.

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