• Networking

  • All of sudden, very high ADSL attenuation.

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.
I can buy one on the internet but I'm hesitating. Better if I can install it even before the telephone box.

There are conditions that should be met for this to be effective :



L1 is the line coming from the CO. I am not sure if the line is 26 AWG or 28 AWG since it's very thin and oxidized.

4 months later
Hi Guys,
After 1 year and a half struggling with snr drops.
Today I found out its elevator problem.
Tomorrow ogero will visit me any suggestions ?
Anyone solved similar problem in the past ?
Note: problem is on ogero box too affecting all building.
I had an issue lately and i worked so hard with the ogero guy, first of all i was on fastpath and it was unstable due some electrical stuff i tried all the above changing cables trying directly from box with 1 meter cable to the machine anything you can think of some issues were:
generator cable was hanging very close to the telephone box
at the spreader across the street (mwazi3) he connected my line directly to the coming one instead of passing through a junction
then i switched from fastpath to interleave now my internet is stable at 4mbps
Guys after investigation, my problem with elevator started when the people living in the building decided to make the elevator work with the generator. So they bought an electric inverter which convert triphasé to monophase.
I called the elevator maintenance guy and he said that this inverter causes a hell of interference.
But the thing is that this inverter is located on the roof while ogero box is located in the ground floor.

Everytime someone uses the elevator no matter if EDL or Generator, the problem occurs.
They need to install proper filters, probably inverter made in lebanon and has no compliance with electromagnetic emission standards.
that is weird why do you need an inverter? it is not better for the elevator

i could suggest you to equip the elevator with VVVF that works on triphase and reduces the amperage needed by the elevator to run which significally reduces the electricity bill
ozone1864 wroteGuys after investigation, my problem with elevator started when the people living in the building decided to make the elevator work with the generator. So they bought an electric inverter which convert triphasé to monophase.
I called the elevator maintenance guy and he said that this inverter causes a hell of interference.
But the thing is that this inverter is located on the roof while ogero box is located in the ground floor.

Everytime someone uses the elevator no matter if EDL or Generator, the problem occurs.
This is exactly my situation----when I called that guy said he never heard of any interference, but one of his crew who came to try to address the problem, said it caused inference for others also. It doesn't matter that the device is on the roof, usually the controls for the elevator are in the electric room near where the telephone wires come into the building. They tried attaching 4 filters, none of them did squat as without a ground, they have nowhere to dissipate the EMI.

I put an external cat6 cable and that has reduced the problem, but still will get disconnections when there is heavy use--building is 8 floors + 3 underground so if someone ordered the elevator from the garage and it was near the top floor and then went up near the top floor, I will either get completely disconnected or will temporarily be shut out with an abundance of HEC errors. I also get interference when they run the electric pump for the building, and I am suspecting interference from the electrical room also.
xazbrat wrote
ozone1864 wroteGuys after investigation, my problem with elevator started when the people living in the building decided to make the elevator work with the generator. So they bought an electric inverter which convert triphasé to monophase.
I called the elevator maintenance guy and he said that this inverter causes a hell of interference.
But the thing is that this inverter is located on the roof while ogero box is located in the ground floor.

Everytime someone uses the elevator no matter if EDL or Generator, the problem occurs.
This is exactly my situation----when I called that guy said he never heard of any interference, but one of his crew who came to try to address the problem, said it caused inference for others also. It doesn't matter that the device is on the roof, usually the controls for the elevator are in the electric room near where the telephone wires come into the building. They tried attaching 4 filters, none of them did squat as without a ground, they have nowhere to dissipate the EMI.

I put an external cat6 cable and that has reduced the problem, but still will get disconnections when there is heavy use--building is 8 floors + 3 underground so if someone ordered the elevator from the garage and it was near the top floor and then went up near the top floor, I will either get completely disconnected or will temporarily be shut out with an abundance of HEC errors. I also get interference when they run the electric pump for the building, and I am suspecting interference from the electrical room also.

have you considered to change from fastpath to interleave or you are on interleave already?
Idler wrotethat is weird why do u need an inverter? it is not better for the elevator

i could suggest you to equip the elevator with VVVF that works on triphase and reduces the amperage needed by the elevator to run which significally reduces the electricity bill
This is exactly VFD doing, powering elevator from single phase to triphase.
And if this VFD is cheap (which kinda expected in Lebanon) it has no proper EMI filtering.
nuclearcat wrote
Idler wrotethat is weird why do u need an inverter? it is not better for the elevator

i could suggest you to equip the elevator with VVVF that works on triphase and reduces the amperage needed by the elevator to run which significally reduces the electricity bill
This is exactly VFD doing, powering elevator from single phase to triphase.
And if this VFD is cheap (which kinda expected in Lebanon) it has no proper EMI filtering.
usually they are not cheap speaking about 5K and up, i worked for several years in a elevator company VFD is almost same as VVVF but they are both AC i think he needs a DC solution in my opinion to reduce the noise but i seriously cannot relate why is his electricity being affected by the elevator is it the neutre shared ?
nuclearcat wroteThey need to install proper filters, probably inverter made in lebanon and has no compliance with electromagnetic emission standards.
Tomorrow the person who installed this inverter will come and test without it if the problem will still exist.
But the thing is that its on the roof and ogero box is in the electrical room in the ground floor.