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[JamesK]

Hi All,

I posted a thread last year about the speed drop issues I was experiencing with my BT Infinity connection... details here: http://forum.kitz.co.uk/index.php?topic=12801.msg243638#msg243638

Towards the end of last year I decorated my living room on the middle floor. When I pulled off the BT socket in the room which I thought was not connected I found the green pair of two phone lines connected. When I moved the wiring the modem on the top floor immediately re-sync'd. So instead of the wiring going direct to the top floor of the house as I previously thought it actually went via the living room. As a result I ended up moving the modem down to this socket and immediately gained about 6mbps in speed. So obviously I was very happy. In addition to this I started using an ECI modem in order to match with the ECI DSLAM as I'd read matching them up can give better connection speed and in some cases put you back on fast path.

However, the connection has never gone back to using fast path. But, in the months it's been in the new configuration the connection has never once dropped or re-syncd, so it's nice and stable.

In my living room, right near the modem I've got a 46" Panasonic Plasma TV. It had never occurred to me until reading a thread on here yesterday that they put out significant RF interference.

Is it possible the TV could put out interference that's potentially stopping the DSLAM reverting me to fast path? My wife and I both have busy lives, so the TV doesn't get a huge amount of use - so about one evening during the week and a bit more at weekends.

All my HG612 stats from my issue before were from when the HG612 was in use on the top floor of my house, although the phone wire went into the living room and back out before getting to the modem, but I don't have any current stats because of using the ECI modem. I may at best have about a weeks worth of stats after I moved the HG612, but I'm not sure.

I was wondering what peoples thoughts were on this, and whether it would be worth moving the modem into the kitchen on the ground floor. Or would got quality cable negate the effect the TV could have on the connection?

Many Thanks...

[JGO]

Two ideas

1) AFAIK it isn't a case of Plasma TV = Interference full stop. 

There MAY be something, so a search near the TV with a radio could be useful but in one case I heard of switching on the TV reduced sync  speed 95%,  fairly easy to diagnose !!!! Also there is some anecdotal information that Samsung are the worst.

2) If there is interference, it needs a path to the modem, via the power line,  radiation or both. A power line filter at the TV ( can the makers help ?) and  perhaps a RF3 at the modem input should help.

[JamesK]

If I tune a portable radio to around 600 MHz and put it near the phone line I can hear the VDSL signal. Turning the TV on and putting the radio near certainly generates a lot of noise on that frequency straight away.

The broadband connection never drops or re-syncs. A lot of the time when we use that TV it's to watch a film on the Apple TV, and that's always a good 5GB download while the TV is on.

The TV itself is plugged into a Belkin Surgemaster.

[JGO]

Turning the TV on and putting the radio near certainly generates a lot of noise on that frequency straight away.

Any digital device, including a TV will generate noise - what is important is does it degrade your modem's S/N significantly ? If it doesn't then forget it. 

[HighBeta]

Mains conditioner could be an idea :?:

Something like  BT 315029 MCU5A/1000 Conditioning Unit  ?  (Sure burakkucat, will have the spec sheet

[sheddyian]

An AM radio tuned around 600Mhz held near any modern piece of electronics is likely to make a noise, but that noise should quickly fade away when you move the radio away by a metre or so.

If the radio is in the middle of a room, away from anything electrical, and you can still hear the interference, AND you can cause/silence it by powering up / unplugging a particular piece of equipment, be it a TV, computer or external hard drive, then clearly that piece of equipment is at fault.

I had a dodgy internal PC PSU that was radiating noise all around the house via the ring main even when it was switched off.  I could detect it on an AM radio everywhere, even in the shed!  Disconnecting the rogue PC from the mains instantly silenced the noise

I think there's a difference between very localised noise (providing your router/phone line isn't passing through that zone) and a more general widespread "broadcast" of noise from a faulty device.

Ian

[burakkucat]

Sure burakkucat, will have the spec sheet

Thank you for the "vote of confidence". 

To tell the truth, I know very little about those devices and do not have the data or specification sheet! 

[HighBeta]

Don't really know much about mine 

Other than its keeps the line fastpath even with a hg612 on an eci cab over 400m away   

[Ixel]

An AM radio tuned around 600Mhz held near any modern piece of electronics is likely to make a noise, but that noise should quickly fade away when you move the radio away by a metre or so.

If the radio is in the middle of a room, away from anything electrical, and you can still hear the interference, AND you can cause/silence it by powering up / unplugging a particular piece of equipment, be it a TV, computer or external hard drive, then clearly that piece of equipment is at fault.

I had a dodgy internal PC PSU that was radiating noise all around the house via the ring main even when it was switched off.  I could detect it on an AM radio everywhere, even in the shed!  Disconnecting the rogue PC from the mains instantly silenced the noise

I think there's a difference between very localised noise (providing your router/phone line isn't passing through that zone) and a more general widespread "broadcast" of noise from a faulty device.

Ian

Interesting, I might buy a portable AM radio to see if I've got any noise leakage here.

Also what's most people's opinions on mains conditioners, are they worth getting? I presume a surge protector isn't necessarily quite the same thing as a mains conditioner.

[burakkucat]

Currently five are available at a certain on-line auction site. 

[JGO]

Also what's most people's opinions on mains conditioners, are they worth getting? I presume a surge protector isn't necessarily quite the same thing as a mains conditioner.

It is a nice buzzword to delight sales !   Actually it aims to destroy the surge - not protect it.

Seriously a surge protector will have some non-linear device to clip voltage spikes but normally has no effect, OR it limits switch on current, or possibly both.

What is needed for interference suppression is a low-pass filter to keep any  interference in the ADSL/VDSL frequency range from going down the cable, - same principle as the 'phone half of a micro filter but HIGHER POWER RATING !!!! 

[Ixel]

Also what's most people's opinions on mains conditioners, are they worth getting? I presume a surge protector isn't necessarily quite the same thing as a mains conditioner.

It is a nice buzzword to delight sales !   Actually it aims to destroy the surge - not protect it.

Seriously a surge protector will have some non-linear device to clip voltage spikes but normally has no effect, OR it limits switch on current, or possibly both.

What is needed for interference suppression is a low-pass filter to keep any  interference in the ADSL/VDSL frequency range from going down the cable, - same principle as the 'phone half of a micro filter but HIGHER POWER RATING !!!!

Hmm, so are you saying that a mains conditioner is just a marketting ploy, or is better or worse than a surge protector? I didn't completely understand the reply, sorry.

[JGO]

"Mains Conditioner" as a word means little - it doesn't even say good condition !

Switch on surges or spikes can be harmful even destructive so a device which reduces them is beneficial. They will have no effect on other interference travelling down the cable, a properly designed filter is needed.  If someone packages the whole lot and calls it a mains conditioner that is marketing - read the small print !

Getting back to the topic, in my limited experience, plasma oscillations are not like BT's REIN from unsuppressed motors, TV sets  etc but an ill-defined noise covering a band of frequencies. A quick web search seems to suggest between 3.5 and 4 MHz + harmonics. In this case  listening at 612 kHz won't show up much !

The question was could the particular Plasma TV be causing interference ? In fact any electronic device can cause some interference, the real question is how much ?  If it isn't significant then don't worry; you are the nearest user.