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Standard User youngsyp
(regular) Sat 07-Jul-12 11:44:02
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Plasma TV and ADSL2+


[link to this post]
 
Hi there,

I just wanted to canvas opinions on who has interference issues with plasma TV's and their ADSL2+? And what have you done to eliminate it?

My main TV is a 2011 Panasonic plasma display and it's mounted on the wall in the lounge using it's own fused spur (no ferrite cores). It is wired to the router in the loft via a direct length of cat5e cable with a ferrite core at the TV end.
I have an 8 port switch mounted about 4 feet below it that has the Sky box, PS3, Blu-ray player and Xbox360 plugged into it. This again is connected directly to the router in the loft via a length of cat5e cable. No ferrite core.
The router is in the loft and connected directly to the master socket (also in the loft) via a Solwise 'high performance' RJ11 cable and ADSLnation filtered faceplate. The cable from the drop wire to the master socket is a single piece of cat5e cable.
The router power cable has a ferrite core around it, as does the extension power block that the router is plugged into.

Things I plan on trying:

1. Ferrite core around the TV power cable. Difficult as I'll need to take the TV off the wall and it's a (large) 2 man job.

2. Make a foil 'tray' for the router to sit in. How effective will this be considering I need to do it and not hinder the wireless antennas?

Any suggestions and advice woul be much appreciated.

Paul

ISP: Vivaciti
Service: Surfwise ADSL2+ LLU
Exchange: SMYG
MSAN: Broadcom
Router: Billion BiPac 7800N
Attenuation:40dB
SNRM: 6dB
Fastest sync: 11881kbps
Standard User b4dger
(knowledge is power) Sat 07-Jul-12 12:28:14
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Re: Plasma TV and ADSL2+


[re: youngsyp] [link to this post]
 
Sorry if I've missed it in your post but are you saying your TV is causing noise?
i.e. I take you've monitored things with the TV on/off?

There have been a few Plasma TV threads in the past on TBB so prob worth a search...

Standard User youngsyp
(regular) Sat 07-Jul-12 12:58:19
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Re: Plasma TV and ADSL2+


[re: b4dger] [link to this post]
 
Hi,

Yes, definitely the TV. I don't thing it's RF simply due to the proximity of the ADSL kit to the TV. So, it must sticking the nastiness up the mains.

I've 'googled it' too and seen a few threads but, none of them seemed to actually solve the issue, other than buy getting rid of the TV. That's not an option for me as I love my TV. smile

I've put a choke around the TV power lead and it seems to have little to no effect. I'm considering a mains conditioner next...

Paul

ISP: Vivaciti
Service: Surfwise ADSL2+ LLU
Exchange: SMYG
MSAN: Broadcom
Router: Billion BiPac 7800N
Attenuation:40dB
SNRM: 6dB
Fastest sync: 11881kbps


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Standard User gomezz
(eat-sleep-adslguide) Sat 07-Jul-12 13:36:37
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Re: Plasma TV and ADSL2+


[re: youngsyp] [link to this post]
 
You still seemed to have missed out on detailing the symptoms you are getting. Unless you are hoping we can guess based on the remedial actions you have tried?

O2 Standard (8Mbps LLU)
Standard User youngsyp
(regular) Sat 07-Jul-12 13:56:58
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Re: Plasma TV and ADSL2+


[re: gomezz] [link to this post]
 
Ah yes, you're right. Apologies.

Essentially, my SNR drops by between 0.5dB and 1dB when the TV is on.

I've been doing a little research and it seems a 'delta suppression filter' across the spur where the TV is connected to could be worth a shot...

Paul

ISP: Vivaciti
Service: Surfwise ADSL2+ LLU
Exchange: SMYG
MSAN: Broadcom
Router: Billion BiPac 7800N
Attenuation:40dB
SNRM: 6dB
Fastest sync: 11881kbps
Standard User XRaySpeX
(eat-sleep-adslguide) Sat 07-Jul-12 14:56:23
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Re: Plasma TV and ADSL2+


[re: youngsyp] [link to this post]
 
In reply to a post by youngsyp:
Essentially, my SNR drops by between 0.5dB and 1dB when the TV is on.
That's where you should have started. It was like going to the Doc and saying that you are ill and you've taken pill A and pill B and laid down and you are still ill wink.

That's not much of a reduction in the NM if you really mean "BY" and not "TO".

Does it just reduce or are you having resyncs at same time.

Could you be confusing TV ON with nighttime?

You come home, turn the TV on at night and then notice NM drop. You conclude it was switching on TV that caused it, but it could just be the normal small drop that happens after dark.

1999: Freeserve 48K Dial-Up => 2005: Wanadoo 1 Meg BB => 2007: Orange 2 Meg BB => 2008: Orange 8 Meg LLU => 2010: Orange 16 Meg LLU => 2011: Orange 19 Meg WBC
Standard User sbrads
(member) Sat 07-Jul-12 15:02:17
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Re: Plasma TV and ADSL2+


[re: youngsyp] [link to this post]
 
Get another ferrite ring and wind the ADSL lead to the master socket a few turns round it at the router end. Your lower SNR is likely happening due to this lead acting as an aerial. The ferrite will not reduce the real ADSL signal at all. The DC lead can also act as an aerial but you seem to have that one sorted.

Steve
Standard User eckiedoo
(learned) Sat 07-Jul-12 15:07:48
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Re: Plasma TV and ADSL2+


[re: youngsyp] [link to this post]
 
As your Router is up in your loft, a metal tray would generally reduce the WiFi signal reaching the main inhabited parts of your house.

Similarly, the WiFi signals from the user devices back to the router would almost certainly be attenuated.

As the WiFi signals are very small in the first place, try moving the router to a more accessible location in the main body of the house, unless of course, other circumstances prevent that.

An analogy would be trying to illuminate the complete interior of the house, using a single torch bulb, LED or similar at the present router location.

If the router has an external aerial, it may be possible to replace it with a directional one etc.

Within the loft, you may be able to improve the situation by moving the router to a location further from the plasma TV, although clearly that may have implications regarding using a phone extension cable - but relatively cheap to try.

It seems strange that the phone master socket is in the loft, as usually they are fitted in less inconvenient places such as the back of cupboards, to allow "easy access" for phone line tests.

===========================

I haven't checked the details of plasma TV screens; but generally plasma is associated with electrical interference, such as emanates from lightning, arc welding and the like.

Regarding ferrite cores for cables, I have seen and used split ones, which may be more readily fitted to your TV, possibly avoiding the 2-man lift.
Administrator MrSaffron
(staff) Sat 07-Jul-12 15:47:29
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Re: Plasma TV and ADSL2+


[re: youngsyp] [link to this post]
 
Noise affecting ADSL margins via mains bourne sources is rare.

More likely to be RF radiated from the plasma itself. though saying that a drop of 0.5 to 1dB, assuming you have a 6dB target value to start with should not cause any issues.

Is the ADSL lead from filter to modem, a twisted pair cable, or the normal cheap one supplied with the router? Also you have done all the usual things of removing ring wires etc

Andrew Ferguson, andrew@thinkbroadband.com
www.thinkbroadband.com - formerly known as ADSLguide.org.uk
The author of the above post is a thinkbroadband staff member. It may not constitute an official statement on behalf of thinkbroadband.
Standard User Zarjaz
(knowledge is power) Sat 07-Jul-12 17:49:42
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Re: Plasma TV and ADSL2+


[re: XRaySpeX] [link to this post]
 
That's not much of a reduction in the NM if you really mean "BY" and not "TO".

Agreed, not really worth worrying about. Now, if it were flooding the signal with errors, when turned on. That would be a different story.

If the OP is quibbling about .5 to 1 db snr loss, I'd say watch MORE telly and less router stats.

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