• Networking

  • All of sudden, very high ADSL attenuation.

Guys, I'm dealing with a very complicated issue. Suddenly, out of the blue, my modem started syncing at 512kbps. Attention increased from 14 to 32dB.

I get frequent disonnections and the modem keeps resyncing. Ogero guys came and confirmed that the issue is with the wire going from ground floor to my apartment.

It's my parent's house, a relative old building and chaging the internal wires is out of question. The only possible solution i can think of is an external phone cable but I still prefer to fix it rather than doing some work around.

How can a 20 y old phone cable go bad all of sudden? anyone experience anything similar ?
Interference could be the issue check for electic magnetic interference I have a problem with SNR drops the connection everytime the elevator works...
leblinux wroteI have a problem with SNR drops the connection everytime the elevator works...
Out of topic, but every time I see a post from "the elevator guy" I crack up sarcastically. I'm in the same boat :)
Attenuation usually mean impedance.
Check all joints/connectors everywhere, maybe some are loose, or if you have it - might be issue with filter.
3 months later
enthralled wrote
leblinux wroteI have a problem with SNR drops the connection everytime the elevator works...
Out of topic, but every time I see a post from "the elevator guy" I crack up sarcastically. I'm in the same boat :)
Did you solve the elevator problem?

When the elevator compeltely powers off I get SNR downstream bumped up to 29 db from 20!
9 months later
same problem here , when elevator on snr goes down to 2 and 3 and connection drops , and when elevator off snr about is about 18 .. anyone solved this problem ?
masrour wrotesame problem here , when elevator on snr goes down to 2 and 3 and connection drops , and when elevator off snr about is about 18 .. anyone solved this problem ?
Did an external line which minimized, although not eliminated the problem. My SNR margin was around 12 before and it went up to the low 20's after I did it, and will drop down to 10 or so if the elevator uses the full 13 floors. Also, try to connect to g.dmt if you can---seemed to be the most stable for me, but this may depend on your current speed and connection (if >8mbps, then won't work fro you)
I've done everything possible , changed the tele. line to CAT6A and put it external and also changed to G.DMT but snr keeps dropping .. idm support guy tels me that i need to put noise cancellation filter in the electric room in the building and it cost above 200$ without electrical engineer fees
masrour wroteI've done everything possible , changed the tele. line to CAT6A and put it external and also changed to G.DMT but snr keeps dropping .. idm support guy tels me that i need to put noise cancellation filter in the electric room in the building and it cost above 200$ without electrical engineer fees
For best results on using CAT6 DIYs is to replace the old cooper wire from the Ogero box directly to your modem without going through your building internal wires. The reason behind this is that if you use hybrid wiring (CAt6/Internal building wire) the benefit of cat6 which is to reduce cross talk interference to stabilize your connection is minimized and thus having poor results.
I've putted it directly to ogero main box and also same results ,the problem is in all the electrical room , my neighbours also facing the same problem
masrour wroteI've done everything possible , changed the tele. line to CAT6A and put it external and also changed to G.DMT but snr keeps dropping .. idm support guy tels me that i need to put noise cancellation filter in the electric room in the building and it cost above 200$ without electrical engineer fees
If that is the cure, see if the neighbors will chip in---any reputable firm that puts one in will test it when they install it so if it doesn't work, then you won't be stuck installing a useless item. The ultimate solution is to ground the elevator, but that is also the most expensive.
7 months later
A quick follow up. It was solved back in time by using an external telephone line. Now a quick observation :

When electricity is on ( EDL or generator ) :

Downstream Upstream
Actual Rate 17261 Kbps 935 Kbps
Attainable Rate 17420 Kbps 968 Kbps

During a power outage which lasts maximum 2 minutes.


Downstream Upstream
Actual Rate 17261 Kbps 935 Kbps
Attainable Rate 21924 Kbps 977 Kbps.


That's almost 4.5 mbps of difference. I did few tests and it looks like the apartment electricity was not the culprit. It has to do with the building.

I tried with the concierge to disconnect all the apartments from power so that the elevator only gets power from the generator ( impossible to disconnect the elevator as it's directly connected to the generator ) and it looks like the sync rate remained at 17mbps.

Only when everything is switched off, the sync rate goes back to 20+mbps.

Now this might be something normal but I don't think 7-8dB of additional attenuation is something I can digest specially when I'm thinking of moving to VDSL2.

Has anyone experienced an attenuation as high as that? It's worth mentioning that the elevator operation doesn't seem to affect the results. Whether on standby or operating, the attenuation is the same.
Might be everything of all, noise of powerlines, appliances connected to it (most shitty stuff sellers getting to Lebanon has no certifications), even just shitty triac water heater can make power line noisy as hell.
Interference is terrible thing.
Once wifi rates in apartment was dropped due crappy CFL lamps owner installed.
Another example, critical site in one of exUSSR countries, we had to sweep one city block to find old guy with malfunctioning TV that was causing interference to huge satellite dish 8km away.

Did you try following things:
1)Put modem in box with small UPS (maybe DC ups, if u will find it)
2)Get with laptop to telephone cables box, find yours
3)disconnect telephone wires going to apartment
4)connect to box, your telephone wires, check speed
5)just connect back wires to apartment, check speed
nuclearcat wroteMight be everything of all, noise of powerlines, appliances connected to it (most shitty stuff sellers getting to Lebanon has no certifications), even just shitty triac water heater can make power line noisy as hell.
Interference is terrible thing.
Once wifi rates in apartment was dropped due crappy CFL lamps owner installed.
Another example, critical site in one of exUSSR countries, we had to sweep one city block to find old guy with malfunctioning TV that was causing interference to huge satellite dish 8km away.

Did you try following things:
1)Put modem in box with small UPS (maybe DC ups, if u will find it)
2)Get with laptop to telephone cables box, find yours
3)disconnect telephone wires going to apartment
4)connect to box, your telephone wires, check speed
5)just connect back wires to apartment, check speed

Did you try following things:

1)Put modem in box with small UPS (maybe DC ups, if u will find it)

Modem connected to online sinewave UPS

2)Get with laptop to telephone cables box, find yours

I have the wire labeled by Ogero tech.

3)disconnect telephone wires going to apartment

Disconnected now from the box.


4)connect to box, your telephone wires, check speed

Almost same attenuation, 0.6 dB difference.


5)just connect back wires to apartment, check speed


OK so it looks like the telephone line is not to blame. It's the telephone box that is experiencing some kind of interference.

Today at 9 AM, i waited for the power outage and checked the attenuation at the telephone box in the building.

8 :59 AM : Attenuation 22 dB ( EDL )
9: 00 AM : Power outage for 1 minute before generate kicks in - Attenuation 13 dB
9: 01 AM : Generator online - Attenuation 22 dB

So back to square one and yeah, 9 dB interference is f****ng a lot.
Kareem wrote
nuclearcat wroteMight be everything of all, noise of powerlines, appliances connected to it (most shitty stuff sellers getting to Lebanon has no certifications), even just shitty triac water heater can make power line noisy as hell.
Interference is terrible thing.
Once wifi rates in apartment was dropped due crappy CFL lamps owner installed.
Another example, critical site in one of exUSSR countries, we had to sweep one city block to find old guy with malfunctioning TV that was causing interference to huge satellite dish 8km away.

Did you try following things:
1)Put modem in box with small UPS (maybe DC ups, if u will find it)
2)Get with laptop to telephone cables box, find yours
3)disconnect telephone wires going to apartment
4)connect to box, your telephone wires, check speed
5)just connect back wires to apartment, check speed

Did you try following things:

1)Put modem in box with small UPS (maybe DC ups, if u will find it)

Modem connected to online sinewave UPS

2)Get with laptop to telephone cables box, find yours

I have the wire labeled by Ogero tech.

3)disconnect telephone wires going to apartment

Disconnected now from the box.


4)connect to box, your telephone wires, check speed

Almost same attenuation, 0.6 dB difference.


5)just connect back wires to apartment, check speed


OK so it looks like the telephone line is not to blame. It's the telephone box that is experiencing some kind of interference.

Today at 9 AM, i waited for the power outage and checked the attenuation at the telephone box in the building.

8 :59 AM : Attenuation 22 dB ( EDL )
9: 00 AM : Power outage for 1 minute before generate kicks in - Attenuation 13 dB
9: 01 AM : Generator online - Attenuation 22 dB

So back to square one and yeah, 9 dB interference is f****ng a lot.
Check if someone in building install new LED or lighting. It happened to me and the restaurant below in the same building has installed new lighting that was affecting the phone box.
2 months later
Ok so I'm officially joining the elevator drama club. I am stuck with three types of interference and I am not able to solve any at the moment.

Every since I switched to VDSL, the line quality has become more and more sensitive which is expected.

I have a CAT6 cable ONLY going from the box to the VDSL modem. It's an external line in a shaft with no cable however the shaft is right beside the elevator room so there's a 20 cm wall block and 4 meters void between my cable and the lift.


What I'm struggling with :

1- Any time the elevator is used, my SNRM drops 5dB. The modem won't disconnect unless it's going through more than 5 floors.
2- My Attainable rate is 30% lower everynight after 10:30 PM until 7:30 AM ( give or take ) and I have no clue.
3- My last interference is certainly not from our building. When electricity goes, my downstream rate goes 4-5 Mbps up. Even when the generator kicks in but then a minute later or so it will go down again.

Any solution for the elevator thing? my 2nd issue is also very difficult to trace; as for the 3rd one I'm positive that it's nothing to do with our building but go convince Ogero.

Ironically my neighbors also reported random disconnections from Ogero during the day mainly and they're on ADSL but not everyone cares.
Hint that CRCs on download build up way much then on the upload... I was hoping that Fiber would solve our problems...
Kareem wroteOk so I'm officially joining the elevator drama club. I am stuck with three types of interference and I am not able to solve any at the moment.

Every since I switched to VDSL, the line quality has become more and more sensitive which is expected.

I have a CAT6 cable ONLY going from the box to the VDSL modem. It's an external line in a shaft with no cable however the shaft is right beside the elevator room so there's a 20 cm wall block and 4 meters void between my cable and the lift.


What I'm struggling with :

1- Any time the elevator is used, my SNRM drops 5dB. The modem won't disconnect unless it's going through more than 5 floors.
2- My Attainable rate is 30% lower everynight after 10:30 PM until 7:30 AM ( give or take ) and I have no clue.
3- My last interference is certainly not from our building. When electricity goes, my downstream rate goes 4-5 Mbps up. Even when the generator kicks in but then a minute later or so it will go down again.

Any solution for the elevator thing? my 2nd issue is also very difficult to trace; as for the 3rd one I'm positive that it's nothing to do with our building but go convince Ogero.

Ironically my neighbors also reported random disconnections from Ogero during the day mainly and they're on ADSL but not everyone cares.
1) Same here, but doesn't disconnect as much as my snr margin is pretty healthy during the day near 14 (but speed sucks). My max attainable speed effectively doubled when I used an external Cat6 cable. What can be done---make sure that there is an emi filter on the elevator and hopefully your building is also grounded for max efficiency (used to be $1000-$1200 for the filter, now who knows). In my building, there is also a water pump. That reduces my max attainable by some 40% too and disconnects me when if first starts.

2) I have a similar issue and I am pretty sure it is the building lights. I noticed one day that the natour did not turn off the lights pretty late (11ish am) and I was getting the same reduction in speed. When I came back, lights were off and my speed was back to normal.

3) This could be anything---a fridge or AC starting up and it doesn't need to be in your apartment. Maybe someone has a voltage stabilizer somewhere near the telephone lines down in the electricity room.

Frustrating to find these things out as proper grounding would take out a lot of these issues at the beginning.
Has anyone tried something like this? I have some cash to burn but I don't really wanna rush.



Thing is even with CAT6 the SNR and the attainable rate at the building box is higher. Say If I install this at the box, would that be helpful to maintain a stable low SNR without disconnections or interference?
Kareem wroteHas anyone tried something like this? I have some cash to burn but I don't really wanna rush.

https://i.gyazo.com/c85e5fcc59b357af8ed25658d9faf30c.png

Thing is even with CAT6 the SNR and the attainable rate at the building box is higher. Say If I install this at the box, would that be helpful to maintain a stable low SNR without disconnections or interference?
Did you find one in Lebanon? See my post at Ogero thread for a similar problem.
One engineer suggested that for me but he said it is without guarantees, it may help and it may not.