What to do if TP-LINK WR1043 greatly cuts the speed via WiFI?

Question

WiFi

The problem is different. Let's all go here: How to jam your neighbor's WiFi with your second router?
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Greetings to all! A few days ago, I had an Internet 100 Mbps. I did not settle for a complete weak router from the provider, because the apartment is large, but immediately went and bought a three-antenna WAN router TP-LINK TL-WR1043ND. And everything went smoothly, until I noticed a drop in speed and went to Speedtest ...
The speed for Waffle was 40 Mbps in and 60 out. At first, I thought that these were problems of the provider, but when I connected the laptop with a wire through a router (not even directly), everything jumped up to 95-97 MBIT. The way it should be.
I checked the situation on other devices - also the speed flew off. Then, I used a bunch of different solutions. I called the support of the router, tried all the settings and channels, even found out about the article on Habré with the nuances of Wifi, read and followed what is written there. All devices work in 802.11n mode, I also checked this. But, even when I sit down with a laptop and other devices next to the router, the speed is cut by 2-3 times.
Just in case, I'm attaching a screenshot from Wifi Scanner. It shows that I have no neighbors with the same channels. And yes, I have tried everything. The speed dropped everywhere, but did not increase.
Please advise what to do. Or is this a specific jamb on the router and I need to change it?

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PS Sometimes the speed flies up to 10-20 MBIT even, or even less.

Answer 1

This is a radio, there cannot be such stability as over a wire. The speed is very dependent on the end device. It is necessary to look at what bitrate when connecting to the router.

iwconfig 
eth0      no wireless extensions.

wlan0     IEEE 802.11bgn  ESSID:"3500"  
          Mode:Managed  Frequency:2.442 GHz  Access Point: 4C:5E:0C:09:3E:7B   
          Bit Rate=150 Mb/s   Tx-Power=15 dBm   
          Retry short limit:7   RTS thr:off   Fragment thr:off
          Power Management:off
          Link Quality=70/70  Signal level=-27 dBm  
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:806   Missed beacon:0

lo        no wireless extensions.

[email protected]:~$ speedtest
Retrieving speedtest.net configuration...
Retrieving speedtest.net server list...
Testing from Omskie kabelnye seti Ltd. (217.25.208.2)...
Selecting best server based on latency...
Hosted by Beeline (Omsk) [2.82 km]: 31.624 ms
Testing download speed........................................
Download: 75.68 Mbit/s
Testing upload speed..................................................
Upload: 49.02 Mbit/s
[email protected]:~$ speedtest
Retrieving speedtest.net configuration...
Retrieving speedtest.net server list...
Testing from Omskie kabelnye seti Ltd. (217.25.208.2)...
Selecting best server based on latency...
Hosted by Beeline (Omsk) [2.82 km]: 22.355 ms
Testing download speed........................................
Download: 79.20 Mbit/s
Testing upload speed..................................................
Upload: 48.65 Mbit/s

Answer 2

most likely the channels are clogged. switch to those that are free

Answer 3

From the router documentation:
The data range or coverage area of ​​your wireless connection is largely dependent on the physical location of the router. For best results, locate your router:
Near the intended center of the zone in which you plan to use your wireless station.
Above the working area at a height, for example, on a cabinet.
================> Away from potential sources of interference such as computers, microwave ovens and corded phones.<================ ==
With vertically raised antenna.
Away from large metal surfaces.