How to check the signal strength of each device in Xiaomi router? I read through the 62 channels at home, and there was a difference between -67 and -74.

Last week, my sweeping robot was lying in the middle of the corridor again. The App showed "device offline". When I squatted down in the corridor and carried it back to the charging base, it came back to life. In the past, when this happened, I would just restart the router and try my luck. This time is different - a few days ago, I showed my cousin the backend of his router. I pointed at a column of negative numbers in the device list and asked him what it was. He guessed "traffic." When I got home, I read the signal strengths of the 62 devices at home one by one. After reading it, I realized that the signal strength of the sweeper was already as bad as -78 in the places where the sweeper was lying. Offline is not a metaphysics, but the numbers are clearly written there. I didn't understand it at all before. This article will explain this deeply hidden number thoroughly.: Where to read, how to read, and how far you should read it.

Find that number first: There are two entrances, both in remote locations.

Open the browser on your computer 192.168.31.1 , log in to the backend, and the home page is the device list. The key action is Click on that row of devices ——The list page only has names and icons, and the number of signals is hidden in the details. After clicking in, there is a "Signal Strength" column in the panel, a negative number in dBm, such as -58. The entrance on the mobile phone is in the Mijia App: Enter the router device card and see the list of connected devices. You can also click on the details page of a certain device to see it. By the way, the device details of some old firmware in the Mijia App only give "signal: "Strong/average/weak" three levels of text, no specific numbers are given - it depends on the number, the web version backend is more complete, what things are there in the backend that Mijia can't do, I'm here 31.1 Backstage panorama I went through the menus one by one in that article.

Let’s talk about the number itself first. dBm is a unit of power, a negative number, The closer to 0, the stronger . This is the most counter-intuitive place: -45 is better than -70, and it is easy for a novice to read it backwards at first glance. Why is it negative? It is a logarithmic value calculated by comparing the measured power with 1 milliwatt. The power of WiFi when it reaches the mobile phone is very small, so it is all in the negative range. You don’t need to delve into the formula, just remember “the more negative it is, the worse it is.” If you want to understand the ins and outs of the dBm unit itself, I used to -What does 65dBm mean? I talked about it in pieces in that article.

My reconciliation sheet: 62 devices look like this when read

It's useless to just understand the units, you have to know "what the numbers at home should look like." I read through the 62 units at home and selected typical ones for you - first explain the equipment configuration: AX3000T is the main router, Mesh has a sub-node, and the whole house is mainly 2.4G (there are many smart devices).

You can probably figure out the gradient by looking at this table. My own line drawing is also based on my repeated experience in the past two months.:

-Within 60, you can use it as you like. I never take a second look at the devices in this range, whether they are mobile phones or sockets. -60 to -70, it works but starts accounting. It is normal for smart devices in this range (temperature and hygrometers, panels, etc.) to disconnect occasionally. My thermometer and hygrometer -67 was left for a month and disconnected twice. I just reconnected and it was fine. After -70, it's time to take action. The sweeper one -71 and the camera one -74 are the precursors of lagging and freezing. I will tell you how to save them later. -Below 80, it is basically on the verge of losing contact. , continuous and intermittent, the App will give you offline performances every three days. These lines are not official standards. The designation of -65 and -70 is also common in dBm popular science articles. They are similar. I have calibrated them according to the actual performance of my own equipment.

Signal strength and negotiated rate are two-line numbers. Don’t look at the string.

There is often a line "speed" next to the signal strength in the device details. Many people mix the two numbers together. My cousin did it: Seeing that the signal on his mobile phone was -72 and the speed was 72Mbps, he thought, "These two are matched, the signal is 72 and the speed is 72." It was purely a coincidence, and the coincidence was just right to put him in a ditch - the signal was a negative number and he automatically ignored the negative sign, the speed was a negotiated speed and it was a matter of another dimension. How to read the rate in this line and how much is considered normal? I just did it last week What is the normal WiFi speed? I have thoroughly explained the three-month reconciliation, one sentence version: The measured speed is roughly half of the negotiated speed, which is different from the signal strength.

There is indeed a relationship between the two accounts.: The worse the signal, the lower the negotiated rate will be. The phone negotiates 2882 when it is -42 in the living room, and may drop to 866 or even 433 when it reaches -67 in the bedroom. So if "the network speed is slow", first check the negative number in the signal line. The signal line is still within -60, and then check the account for negotiation and traffic theft - the method to check who is stealing the traffic is Three real culprits of slow Internet speed In that article.

Three misreadings, I stepped on them all

first one: Use the number of bars in the phone's status bar as the signal strength. The number of grids is drawn by the mobile phone manufacturer cutting dBm into three and four levels. On most mobile phones, -30 to -60 are displayed as full scale, with a difference of more than 20 dB in the middle. My mobile phone still shows the location where my sweeper is lying. It looks like "okay", but the actual value is -78. The grid number is half a beat slower, the dual frequency is combined into one, and the grid number of 2.4G is used to fool you. I’m here to account for this. Full but slow It was calculated in that article. To see the real number, go back to the router and read it in the background.

second: Only reads on the "currently connected node" of the device. The same device in a Mesh home may be connected to the main router today and the child node tomorrow. The signal strength is the reading of "the node it is currently connected to." The camera in my corridor used to be -58, but one day it changed to -74, which shocked me. I spent a long time before I found out that it had roamed to the main router, and the mesh returned with a flicker. Therefore, the readings should be read for several days in a row before looking at the trend. Single-day numbers can be deceiving. How to troubleshoot the weak signal on the sub-router side? The path I took is Mesh sub-router is out of network In that article.

third: 2.4G equipment and 5G equipment should be measured with the same ruler. 2.4G has strong wall penetration and slow attenuation. It is normal to read -65 on 2.4G in the bedroom. ； 5G will fall off if it goes through a wall. It is not surprising that it is -73 in the same position. If you want to compare, compare with similar ones.: It only makes sense that they are both 2.4G thermometers and hygrometers, -67 in the bedroom and -52 in the living room. There is also a hidden pit: Which frequency band the device is connected to when the dual-band is integrated into one is marked in the background device details. Keep an eye on this, otherwise you will adjust to the wrong target after a long time of adjustment. The three steps to dismantle dual-frequency integration into one are: 2.4G and 5G are separated In that article, it was the fault of my sweeping machine that the network connection got stuck.

After reading to -70, the order of action is arranged for you.

Before starting the investigation, you must first identify where the "poor signal" lesions are, otherwise it will be in vain. My sequence is four steps, from zero cost to small money:

first step, Let’s first see if it’s a common phenomenon . Pull up the entire device list (recognizing who the device is is the key to Device recognition In that article, a bunch of Android and MAC addresses are all recognized by four). If the 2.4G devices in the whole house are below -75, it is not about which device, but about the location of the router or the penetration of the wall. Just skip to the third step. If only one or two are bad and the others are healthy, then it is an individual problem of the equipment, so take the second step.

The second step, Three tips for individual equipment: Move location, change rooms, check the equipment itself . If there is room to move the camera, if you move it half a meter, it may return to -65 ； If the battery voltage of the thermometer and hygrometer is low, the transmit power will also shrink. Replacing the battery can bring the number back a bit. ； It is really important to install a cheap signal amplifier to fill that room. Is the amplifier worth the 49 yuan? Actual measurement of signal amplifier It was settled in that article.

The third step, Generally weak, adjust the router side first . Set the "Wi-Fi Settings" in the background to the lowest signal strength level three, and change the default "Standard" to "Through-the-Wall". I actually found 8 dB in the toilet - this is the most cost-effective step in the entire tuning chain. The complete three-step tuning sequence is at Poor signal, weak through walls In that article, I saved the toilet from -72 to -64 in that order. I also took a quick look at the channels. 2.4G are clustered together on the same channel. No matter how good the signal numbers are, the signal numbers are crowded. Look for 1, 6, and 11. I used the experience gained from a night of offline notifications to do this. How to choose channel In that article.

In the fourth step, after all the above is done and there are still dead spots, it is the time to add nodes to the Mesh. The -74 camera in my corridor was finally solved by adding sub-nodes, and is now stable at -55. Don’t take it hard if you are already here. If your device keeps disconnecting, it will cause trouble for you again and again.

ending: My current reading habits

Now this reading method has become a habit in my family.: Pull up the entire backend device list every two weeks (with 1497's device identification skills, 62 devices can be found in ten minutes), only look at the signal strength column, and directly cross out anything within -60, count the frequency of disconnections from -60 to -70, and enter the "to-be-processed list" from -70. When a smart device goes offline, eight times out of ten, you can see the signs in advance at this number, which is much better than waiting for it to slump and restart to try your luck.

Finally, a little tip for judgment: Don’t look at a single point for readings, look at the changes . The equipment slowly slides from -62 to -71. The attenuation in this half month is more worthy of your attention than the absolute value of -71 - either the environment has changed (new large appliances have been added, the furniture has been moved), or the equipment battery is compressed. Numbers are dead, trends are alive. If you have a bunch of smart devices at home that "work sometimes but not work", go to the backend and read the number first. There is a high probability that the answer will be written there. It depends on whether you have recognized it before.