Tracking Down Line Interference

[horntoad]

Thanks, I downloaded a fresh version - rather than using a USB key to copy from my desktop machine. All went as expected.

Relative to my dsl retrains.... things have degraded considerably from my previous bitloading graph. It seems to be related to incoming line or connector, as after I put the cable back into the plastic mounting box, things got worse.

I was suspicious of the data cable AT&T supplied. So I made my own and the bitloading graph on my previous posts were from using that cable. If I re-plug in the AT&T (12 ft) cable, things get worse than they are now.

Technician is coming out tomorrow. Could I have a bad Universal Station protector? or poor grounding on the telephone line (from pole to house) in the NID?

Here is my current status:

[horntoad]

Hi -

This observation has nothing to do with our previous interactions. But I have noticed an interesting anomally on both your pgm screens and the RG screens - relative to MAC addresses of the TV set top boxes. i. e. they differ by a value of +1. You will see the difference in the below screen shots. I'm just curious why this is and how it works.  You'll notice the MAC adrr that ends in :04 on the Channel/Streams screen, now ends in :05 on the COAX/HPNA screen. The set top box displays :5 as it's MAC adddress - very curious??? 

Thanks

[SomeJoe7777 ACE - Geek]

Yes, the U-Verse boxes have two physical network interfaces, one is the Ethernet interface and the other is the coax/HPNA interface.

The MAC address of the coax/HPNA interface is reported in the Coax/HPNA tab, while the MAC address of the Ethernet interface is the one reported in the Channels/Streams tab.

In many STBs, the two MAC addresses are nearly identical except for the final octet, but in others they are not.

As far as your line goes, you have bad interference on the line as well as at least one, possibly more than one bridge tap.  The technician needs to have the I&R group come remove all the bridge taps and condition the line.

[horntoad]

Interesting on the MAC addresses, makes sense since both the RG and STB have coax and RJ45 connectability.

On my line problems - argh... what is a bridge tap and why would I have more than one? (is that a 3M scotchlok?)

Thank you sir!

[ausgewandert]

wow, nice explanation on the troubleshooting of your interference problems. will need to remember this. of course, next time the problem will be entirely different ....

thank you SJ

[SomeJoe7777 ACE - Geek]

A bridge tap is a extra length of wire attached to your pair somewhere in the middle of the run that is not terminated anywhere.  Bridge taps interfere with xDSL services and have to be removed for proper operation.

Bridge taps are usually left over from a different customer who used to use that pair.

[horntoad]

Thank you again. AT&T tech came out this morning and determined this... they installed a new line on the poles this past week and had me "dual connected", not the correct term for this, but this is done so people don't lose phone service when they install a new main line. Good for POTS,  but plays havoc with Uverse lines - ARGH! He corrected the dual connections and things look good. I've noticed I have the fastest max rate I've ever seen, also the largest value for noise margin - YEA! I included screen shots below for reference.

[horntoad]

OOPS.. here is the stats page.

[nzschwabe]

I just got done with my fifth visit from a technician.  We were getting internet and phone, but the router stopped sending a signal for TV to the receivers at night.  I was just about to fire ATT when i discovered a shorted outlet in our house (which is ungrounded as well).  Turns out that the short was knocking out my TV signal.  It would only happen at night when we turned the lights out....meaning more current was going through the electrical short.  When ATT finally sent someone with brains, we discussed the issue and we simultaneously discoved that the coax was grounded.  This is a no-no as any house electrica  interferance will backfeed up the ground wire.  I fixed the outlet short and also removing the yellow ground wire where the 2 wire connects to coax has fixed the problem.  Uverse needs clean power to work right and if you are in old home take note.

--Nick

[RCSMG ACE - Master]

Good job on your part.  Glad you got an educated tech and the problem is now resolved.  Enjoy.

[SomeJoe7777 ACE - Geek]

horntoad,

That bitloading graph and stats look MUCH better.  This looks to be properly working service, and you should have few if any problems now.

[horntoad]

Hi - interesting observation/solution relative to having the coax grounded. When I had both Comcast and Direct TV, they grounded the coax splitter. I have grounded the AT&T coax splitter as well.

My ground wire is connected from the coax spiltter to the cold water pipe.

It was my understanding that having it grounded would pass the interference TO ground, not the opposite.

I welcome further information/discussion on this.

[Kramer_1984]

I know this is an old post but I'm having a similar issue with "dirty electricity" line interference in the house and maybe someone can point me in the right direction. 

I noticed while watching live or recorded tv from my wireless receiver the show freezes intermittentely. I moved the WAP within 10ft. of the TV with no success. I began to notice that while my TV is freezing my furnace is running too.

So where do I start? What should I be checking for first?

I've purchased some ferrite magnets for the WAP power cord hoping I can reduce some noise but I haven't tried it yet. Anyone else have suggestions?

[aviewer ACE - Wizard]

Kramer_1984 - Is your furnace an oil burner?? Do you have it serviced annually??

It has a couple motors where the brushes could be noisy. What I am curious about is the igniter. I can see where that could be quite noisy (electrically speaking). But, I believe it should only operate for a short period of time. Not continuously like the motors. Perhaps a control is sticking.

A previous post suggested looking for electrical noise with an am radio. Maybe try that near the furnace. Also, some folks had power bricks go bad. Check those out with the am radio.

[Kramer_1984]

I'll give the AM Radio test a chance tonight and will also try to relocate the gateway power supply to a different outlet using a long extention cord. Also, the furnace is not an oil burner type, it's a 2 yr. old high efficiency Lennox gas furnace.

I'll post my findings.

Thanks.

[ScottMac]

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Kramer_1984 wrote:

I'll give the AM Radio test a chance tonight and will also try to relocate the gateway power supply to a different outlet using a long extention cord. Also, the furnace is not an oil burner type, it's a 2 yr. old high efficiency Lennox gas furnace.

I'll post my findings.

Thanks.

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It is possible (though I haven't personally seen it),that the gas modulator for high efficiency furnaces can generate / radiate electrical noise.

The modulator is the pulsing mechamism that some / many furnaces use to regulate the gas flow as part of the efficiency mechanism.

[Kramer_1984]

I think you're on to something...I unplugged the gateway? (modem), WAP, and wireless receiver to different outlets in the house using extenstion cords...nothing helped, not even wrapping the wireless wire around a ferrite core. I don't remember having this issue with the A/C running. Also, there was no issue watching TV with DISH although we were using COAX.

I did call ATT Technical Support and will have a Tech out tomorrow. I downloaded Scott's realtime software and found an issue with my service but I don't think it will correct the interfernce issue. What you you guys think? 

[aviewer ACE - Wizard]

Kramer_1984 - I am not an expert on realtime, but the bitloading does not look like the good ones I have seen.

Since we are trying to rule out (or in) the furnace - can you generate the bitloading with and without the furnace running?

I assume (hope) the one you show is with the furnace running. Although, it would be great to identify the source, it still leaves the question of how to stop it. Guess I will Google it.

Check it out - https://www.google.com/search?hl=en&as_q=high+efficiency+gas+furnace+generates+emi+interference&as_e...

[Kramer_1984]

If my memory serves me correctly the bitloading shot was taken with the furnace running...but I later checked realtime again (furnace not running) and the graph looked the same. Somewhere in the forum I saw a realtime graph like mine yesterday and now I can't find it. If I remember reading correctly the ATT Tech ran CAT6 from the NID to the Gateway. Something about twisted pairs...ARGH... I wish I could find that topic.

[Kramer_1984]

Looks like I will be contacing my Lennox Dealer.....

http://www.cozyparts.com/lennox-parts/forum/topic.asp?TOPIC_ID=4295&whichpage=2

[aviewer ACE - Wizard]

Kramer_1984 - The power of the inernet!!

Props to you for zeroing in on the furnace.

[ScottMac]

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Kramer_1984 wrote:
Looks like I will be contacing my Lennox Dealer.....

http://www.cozyparts.com/lennox-parts/forum/topic.asp?TOPIC_ID=4295&whichpage=2

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Not to create another zombie post, but did the new control board for your furnace correct the noise issue?

If so, can you please post the new UVRT stats?

Thanks!