In reply to a post by youngsyp:

So it's just a huge coincidence that the moment I switch the TV on, the SNRM drops and the instant I turn the TV off, the SNRN rises back to 'normal' again?

If you care to google the phrase "plasma TV affecting ADSL", you'll see a huge number of hits where people have seen the same or similar issues to mine. Just because you've not experienced it, doesn't mean it doesn't happen.

I thank you for the condescending tone of your response though.

Paul

well I'm sorry you find my post condescending and that is most regretful but where all the equipment is powered by a proper 6/8 mains filter with RF i myself have never seen your problem but i have seen it in many houses that do not have a filtered main socket sorry i couldn't have helped you

http://www.amazon.co.uk/Tacima-Conditioner-Frequency...

Edited by NICK_ADSL_UK (Sun 08-Jul-12 15:16:27)

Hi,

It makes no difference whether I switch the TV on from off or from standby.

Please find below a link to an image showing exactly the issue. The red circled area was recorded when I turned the TV into standby, left it for 4 minutes or so, then switched it back on again.

http://i51.photobucket.com/albums/f365/youngsy/Route...

Paul

In reply to a post by NICK_ADSL_UK:

well I'm sorry you find my post condescending and that is most regretful but where all the equipment is powered by a proper 6/8 mains filter with RF i myself have never seen your problem but i have seen it in many houses that do not have a filtered main socket sorry i couldn't have helped you

http://www.amazon.co.uk/Tacima-Conditioner-Frequency...

Ah, that's not what you wrote originally though. You wrote there are no problems that you know of. There was no caveat with regards to using a mains conditioner... You've also contradicted yourself with the final part of your response. You clearly have seen it before but, don't experience it yourself.

I use one of the linked items for my AV kit. As the TV is on the wall, it has it's own fused spur so, I couldn't use one of those for its power delivery. However, buying one of those mains conditioners for the router is one of my next steps.
If I recall correctly, I've cured an issue with ADSL before using a mains conditioner.

Paul

Just in case anyone else is experiencing similar issues, I 'think' I may have improved on the problem.

When I wired up my cat5e cable from the drop wire to the master socket in the loft, I only connected 2 pair per leg, leaving another 2 pair un-connected. Not only do I have a street light directly infront of where the drop wire comes out of the ground but, I suspect the cat5e cable runs very close to the TV. As most of you are aware, those un-connected pairs would have been acting as an antenna for any airbourne noise.
So, I've now connected all 4 pairs up so that each leg of the drop wire has 2 pairs of the cat5e cable connected to it. Last night I didn't get a drop in connection like I'd normally get and the action of switching on the TV causes a 0.2 to 0.4dB drop in SNRM where as previously, it would cause a 1dB drop. The drop now seems to have some relationship with the target SNRM that's set...
Interestingly, some form of noise disappears at around 12.38am as there's a distinct increase in SNRM at that time. Figuring out what that is is the next step.

I tried a mains conditioner on the router and that made zero difference. But, I will be putting a choke on each end of the feed to the master socket and at each end of the two other long cat5e runs I have that run near the TV.
I've also bought a new 'pre-filtered' socket to replace the master socket and faceplate. The current faceplate is around 6 years old and the type are known to fail so, it's a pre-cautionary step. The new socket also features better connectivity which should hopefully reduce any resistance further.

Other things I've done:

Verified master socket connection polarity (-50v DC on 'B' leg).
Swapped ADSLnation Pro ADSL cable for Belkin high speed ADSL cable. This increased attenuation but, the ADSLnation cable is 1m long whereas the Belkin cable is 3m long. Needless to say, I've switched back to the ADSLnation cable.

Paul

In reply to a post by youngsyp:

When I wired up my cat5e cable from the drop wire to the master socket in the loft, I only connected 2 pair per leg, leaving another 2 pair un-connected.

Could you elaborate on this "2 pair per leg" as I have either not understood correctly or you've done somthing very wrong!

It could just be your definition of pairs and legs but I would regard a "leg" as a single wire within the (twisted) pair. Hence, a pair consists of 2 legs (twisted). Therefore when you say 2 pair per leg that suggests 4 legs (ethernet) per 1 leg (dropwire), which, although possible, is not good wiring practice!

Are you saying that have terminated 2 ethernet pairs (as pairs or splits) to EACH incoming leg (wire) of the dropwire pair.

For example dropwire a-leg to ethernet pairs 1 and 2, and b-leg to ethernet pairs 3 and 4?

(Sorry, difficult to express with words, a picture would be better!)

If this is what you meant (or similar) then this is effectivley untwists the pairs leading to
longitudinal imbalance along the ethernet cable and consequently EMI noise ingress if the cable is of sufficient length and proximity to mains etc.

Just in case you have done this. I would advise you do this instead:

Dropwire pair 1 a-leg (orange) to ethernet pair 1 a-leg (white/blue stripe)

Dropwire pair 1 b-leg (white) to ethernet pair 1 b-leg (blue/white stripe)

Unused ethernet pairs 2, 3, 4 (orange, green, brown) leave disconnected each end (or earth either end if inclined)

Unused dropwire pair (green/black) leave disconnected (unless you have a 2nd line LOL!)

Also incoming cables are not always "dropwire" and so colour coding may be different. However, you have already identified incoming pair so you simply need to make sure it is just connected to the 1 pair of ethernet (if not already).

Hope that helps a little.

Edited by deleted (Sat 21-Jul-12 00:12:41)

When I was using my old Netgear DG834 router, when I turned my Panasonic plasma on ADSL2+ would completely cut out. It wouldn't lose sync but I was getting virtually zero throughput. I got put back on ADSL and then the plasma didn't affect my connection. A few months later I disconnected the ring wire at the master sockets and all extentions (my router isn't connected to the master socket) and I replaced the router with a Billion Bipac 7800n. I then dared to try ADSL2+ again. The plasma no longer affects my connection and I'm syncing at 15 meg.

Yep - that "ring wire" can be a killer whatever flavour of ADSL you are on!

Just have wires connected to terminals 2 and 5...!

In a nutshell, yes, that's what I've done. 2 out of the 4 twisted pairs to each drop wire leg.

Could you explain how that effectively un-twists the 4 pairs and induces EMI? As mentioned, I saw a definite improvement in the noise on the line and stability of the line which would contradict your statement.

At a very basic level, what I've done is reduce resistance by using more copper.

Also, wouldn't the un-connected ethernet cables act as an antenna for noise if they're not terminated?

I'm not trying to be argumentative but, as mentioned the practice doesn't tie up with your theory.

Thanks,

Paul

If the original wiring was

Blue with white stripe and
white with blue stripe

What you should have done is

Connect Green with white stripe to the blue with white strip at end end

then

White with green stripe to the blue with white stripe.

This should lower resistance, and keep noise amountity. The resistance over a few metres wiring in the home though is minimal compared to the drop in the street to the exchange

The drop wiring is orange and white I believe...

Clearly the cable between the socket and the exchange will offer the greatest resistance in the circuit however, any reduction is worthwhile especially when it just involves connecting a couple more wires.

Regardless, I'll give the theory a test at the weekend and see if it improves noise on the line. Again, it'll only mean disconnecting a few wires.

Paul