Network setup problem

[demenicon]

Hello everyone , I'm not very experienced with networking and here is my problem.

I have 2 TP-Link routers of the same model (wr841n) and a modem which are connected to my PC Wi-Fi card (wdn4800) , everything with the latest drivers installed.http://imgur.com/mdNbVi6

Before that I used to simply connect my PC to modem , and I've got around ~60% of Signal strength (It was sort of stable) .But I want to get a solid and consistent signal.

I've set up a bridge with 2 new routers according to this guide. http://blog.jeffcosta.com/2011/09/29/create-a-wireless-n-bridge-with-2-inexpensive-tp-link-routers/
Although , I have no idea what my Modem settings supposed to be or if they affect bridge setup at all.

My modem settings are http://i.imgur.com/XGwq7r7.png?1
Here are the settings of both routers http://imgur.com/MdaYuD5 .
My bridged router has the 1st channel and it doesn't interfere with other WiFi signals in the area , however router that is connected to my modem (channel 1+5) does overlap with 3 other WiFi signals.

Naturally I've got about ~50-60 Mb/s down on Speedtest with my laptop downstairs. However with bridge setup my connection is quite unstable and drops from average 15-18 Mb/s to 2-6 Mb/s.

So , here are my the questions :

What's causing this interference and how to fix it?

Did I set up the bridge wrong?

Will it help to install dd-wrt on both routers instead of default software?

Should I try another type of connection (e.g Powerline , Repeater etc.)

Thank you in advance.

 

[abailey]

I am having trouble picturing exactly what your talking about. It would help if you could answer these questions:
1) Where is your Modem/Wireless router in relation to your computer (same room, different room same story, different story)?
2)What internet speed were you getting on your computer before the bridge was put in?
3)When you put the bridge in did you turn off the wireless on the Modem/Router?
4)Where are the 2 ends of the bridge located? I assume one is near the modem/router, is the other in the room with the computer?

 

[demenicon]

I am having trouble picturing exactly what your talking about. It would help if you could answer these questions:
1) Where is your Modem/Wireless router in relation to your computer (same room, different room same story, different story)?
2)What internet speed were you getting on your computer before the bridge was put in?
3)When you put the bridge in did you turn off the wireless on the Modem/Router?
4)Where are the 2 ends of the bridge located? I assume one is near the modem/router, is the other in the room with the computer?

1)Check the first Imgur link.Modem+router 1st floor , bridged router on the second and PC on third.
2)Naturally I've got about ~50-60 Mb/s down on Speedtest
3) I tried turning off wireless on the modem , didn't do anything,
4)Modem+Router -----> Router ------>PC

 

[abailey]

Ok. First off it looks like your using 2.4Ghz wireless. If your able to pull 50-60Mbit/s without the bridge, that is really good. In fact you will most likely not get much better even if you were in the same room as the AP. A bridge in repeater mode using WDS cuts your bandwidth in half right from the beginning. There is also increased latency with a bridge. Bridges are really only useful when the signal is unusable at the client device from the original source. Now, also, with 2.4Ghz you don't want to use 40Mhz channels except in the rare instance that you are located away from other houses and you are not using any repeaters or wireless bridges. The problem is that in 2.4Ghz wireless there are really only 3 non-overlapping channels 1,6, and 11. If you use 40Mhz wide channels then you effectively use 2 of the 3 channels, or about 2/3 of the available spectrum. In order to transmit like that the whole spectrum involved has to be quiet. If another device in your house or close to your house is overlapping any, then that can cause delay as your radio has to wait for the spectrum to clear. This usually causes people using 40Mhz wide channels to be slower than those using 20Mhz channels. So if I were you I would definitely force my AP's to use 20Mhz in the 2.4Ghz band.
It is really going to be difficult for you to get much better than 60Mbit through wireless. If you change to 5ghz you may get a little better but it would mean you would have to have an AP very close to your computer. For example I use a 5Ghz wirless N AP in my den. When in the same room my computer shows a 300Mbit link. Since wireless is half duplex you have to divide that number by 2 to compare it to wired connections. So that is 150. Then wireless has a lot of overhead (error correction and such) so you only get about 70% of the stated bandwidth. So for me that is 105Mbit/s. That is exactly what I test at using my test software. Now that is using 5Ghz channels that don't compete with any others in the neighborhood and I am the only client device in the house using that wireless. As you also have competition among the wireless devices in your house that connect to the AP.
So all that to say if you want more speed than what you are getting now you really need a wire (Ethernet wire). Either a wire from the Modem/Router to your PC, or a wire from the Modem/Router to a 5Ghz AP in or real near to the room your PC is in. Powerline and Moca adapters currently do not get much faster than 100Mbit in practice. Most of the time they are less, sometimes (like with powerline adapters) much less. I use a MOCA adapter in my house and it test out at 75Mbit/s.

 

[demenicon]

Thank you for a reply , really appreciate it.

I do have 20 Mhz on both routers and the are on the 1st channel as well , however its not the case.

I'm going to test 5 Ghz tomorrow.

Also , I'm pretty satisfied with my speed , now with stability of the signal though. Therefore I would like to know what network setup would be good in my situation.