Question Powerline speed drops when router is connected

Mar 18, 2020
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Hi all,
2 questions here mainly.
I used to have had 80 mbps on my powerline, now I barely have 30. The only new things I have connected in my room are 2 charging ports but unplugging them doesn't solve anything. Unplugging every powerplug in my room however solves the issue. Any ideas?
Also, my powerline is connected from the 2nd floor to the 3rd floor (my room) and is then connected to my pc and a router (there are 2 ethernet ports on my powerline adapter). When the router is unplugged, I get 55 mbps but when it is plugged in it falls to the 10-30 range (speedtest starts from 9mbps and works its way up to 20-ish) Anyone knows why? My router is about 5m from my powerline and all its antennae are pointing upwards if that even matters.

EDIT: Router in question is the Asus-AC1200G+. Modem is ISP provided and shouldn't matter as it works fine outside my room.
Thanks!
 
Last edited:

Ralston18

Titan
Moderator
Update your post to include network hardware: modem, router (or modem/router if combination device).

It appears that you may have two routers: one on the second floor and one in your bedroom (third floor).

Is that correct?

Does the following line diagram represent the connection path being used?

ISP ----->Modem -----> Router (2nd floor) -----> Powerline adapter (2nd floor) -----> Powerline adapter (3rd floor) ---> PC and ----> Router (3rd floor)

Edit and correct the line diagram as necessary.
 

alceryes

Distinguished
It could be a limitation of the powerline adapter when you are using both ports.
Have you tried plugging just your 2nd router into the powerline adapter and plugging your computer into that router? Can you plug another device into that second powerline port (another laptop or something) instead of the 2nd router to see if the same speed drop occurs?
 
Mar 18, 2020
14
1
15
0
Update your post to include network hardware: modem, router (or modem/router if combination device).

It appears that you may have two routers: one on the second floor and one in your bedroom (third floor).

Is that correct?

Does the following line diagram represent the connection path being used?

ISP ----->Modem -----> Router (2nd floor) -----> Powerline adapter (2nd floor) -----> Powerline adapter (3rd floor) ---> PC and ----> Router (3rd floor)

Edit and correct the line diagram as necessary.
ISP ----->Modem -------> Powerline adapter (2nd floor) -----> Powerline adapter (3rd floor) ---> PC and ----> Router (3rd floor)
Powerline adapter on 2nd floor is connected directly to modem.
 
Mar 18, 2020
14
1
15
0
It could be a limitation of the powerline adapter when you are using both ports.
Have you tried plugging just your 2nd router into the powerline adapter and plugging your computer into that router? Can you plug another device into that second powerline port (another laptop or something) instead of the 2nd router to see if the same speed drop occurs?
To both questions, speed is still the same. Funny thing is, last year when I paid attention to my powerline performance it was still doing fine. There was minimal network loss from powerline to pc.
 
Very strange since the router should do nothing especially if nothing is connected to the router. Be sure some wifi device is not using the router you do not know about.

You should run the asus router as a AP if you are not already. It is not likely your problem but it causes other issues to have 2 routers in your network. If it is running as a AP be sure the LAN IP does not conflict. A duplicate IP address can cause strange issues.

I would try to turn off the wifi radios and make sure nothing is plugged into the router that way you know for sure nothing is eating any bandwidth. The router itself should not produce any traffic.
 

alceryes

Distinguished
To both questions, speed is still the same. Funny thing is, last year when I paid attention to my powerline performance it was still doing fine. There was minimal network loss from powerline to pc.
When you say both the same do you mean it's still the 'slower' speed?
If yes then I find that odd that a router would cut your internet speeds in half. Have you checked all the settings in the router to make sure there's nothing interfering/degrading your speeds? Is QoS on in the router?
Is the 'modem' also a router? How many network ports does it have?
 
Mar 18, 2020
14
1
15
0
Very strange since the router should do nothing especially if nothing is connected to the router. Be sure some wifi device is not using the router you do not know about.

You should run the asus router as a AP if you are not already. It is not likely your problem but it causes other issues to have 2 routers in your network. If it is running as a AP be sure the LAN IP does not conflict. A duplicate IP address can cause strange issues.

I would try to turn off the wifi radios and make sure nothing is plugged into the router that way you know for sure nothing is eating any bandwidth. The router itself should not produce any traffic.
Hey thanks for your reply, if you do not mind me asking whats an AP, and can you link me to something that teaches me how to do so? A newbie here haha, thanks.
EDIT: I figured out what AP mode is, switched my router to AP mode but the speed is still the same. Unplug the router and my speed goes up by 30 mbps. Could this be an electrical interference issue?
 
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Mar 18, 2020
14
1
15
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When you say both the same do you mean it's still the 'slower' speed?
If yes then I find that odd that a router would cut your internet speeds in half. Have you checked all the settings in the router to make sure there's nothing interfering/degrading your speeds? Is QoS on in the router?
Is the 'modem' also a router? How many network ports does it have?
Yup, its still the slower speed. Not sure if my router settings really affects it bc I havent changed it since the last time my powerline was working well. QoS is off, my modem isnt a router and it has 6 network ports.
 
Very strange it almost has to be the power line device. Not sure how you connected the "AP" but if you connect it via the LAN ports it acts as a stupid switch that just happens to have wifi. If you then plug your PC into another lan port on the router/AP I can't see how it would reduce the speed. The only real difference is there is only 1 physical cable into the powerline.
 
Mar 18, 2020
14
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Very strange it almost has to be the power line device. Not sure how you connected the "AP" but if you connect it via the LAN ports it acts as a stupid switch that just happens to have wifi. If you then plug your PC into another lan port on the router/AP I can't see how it would reduce the speed. The only real difference is there is only 1 physical cable into the powerline.
I agree with you, perhaps it could be electrical interference? The powerline works well when the router is unplugged, ONLY when the router is plugged in my speed drops dramatically.
 

alceryes

Distinguished
It's possible that the router is creating extra noise/signal that is forcing the powerline to negotiate a slower speed.
Oh, also, if your 'modem' has 6 network ports it's most likely a router as well. What's the model of the modem? Where is your DHCP coming from? (or are you using static IPs everywhere?)
 
Mar 18, 2020
14
1
15
0
It's possible that the router is creating extra noise/signal that is forcing the powerline to negotiate a slower speed.
Oh, also, if your 'modem' has 6 network ports it's most likely a router as well. What's the model of the modem? Where is your DHCP coming from? (or are you using static IPs everywhere?)
What then can I do to reduce or eliminate the electrical noise from my router? The router and powerline aren't plugged into the same plug but are 5m apart. Also, I don't quite get how my modem causes a drop in my powerline speed?
 
Unplugging every powerplug in my room however solves the issue.
This is the smoking gun in this case. You need to find out which one of these items is doing this. And it's easy too--unplug everything and run the test and then start plugging them in back one at a time, running the test after each one. Once you find the one that causes the problem, put it on a good surge suppressor and that should keep the noise from affecting your powerlines. :)
 

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