CaptainWifi

Interferences

Why at times my connection is very slow ?
Interferences is the # 1 enemy of wifi networks. These are the first sources of slowness on the connection. When you feel slow and you have very low flows. The first reflex is to think of a bandwidth saturation. And yet in 99% of cases this is an interferences problem. The only way to detect it is to proceed some pings on our router.

Why :

  • The first problem : the cohabitation

Wifi standard uses the unlicensed band from 2400Mhz to 2500Mhz. Since this band is unlicensed, everyone can exploit, which is very convenient. The problem is that a lot of people use this frequency band. Radio amateurs, bluetooth, various transmitters, some mobile phones, microwaves. And today, in some area, the 2.4Ghz band is totally crowded.

  • the second problem : Overlapping channels

The standard wifi establishes 13 channels of 20mhz (11 in the US). It is easy to see that it is impossible to make 13 channels of 20mhz wide in a band 100Mhz. And yet, they do. The problem is that the channels instead of being spaced 20mhz to avoid the overlap, are spaced 5mhz apart. So necessarily all the channels overlap. To avoid overlapping, only channels 1, 6 and 11 should be used. In real life, it is the equipment itself that chooses its channel at each startup. If we use channel 1 on one of our antennas and in the neighborhood someone uses channel 2 or 3 there is interferences and we are interfering with each other. With wifi at long distance (over 100m) as we do, the neighborhood is not negligible especially at the Marin or Sainte Anne. Especially that on the water no obstacle stops the wifi. In the middle of the Grenadines, the problem of interferences is not yet too topical.

  • A dynamic radio environment

Why at certain hours it works better than others. Generally at night, the network works very well. Most people sleep, wifi band is not used or little used there is no interference. The nuisance of equipment on adjacent channels is felt only when such equipment is used eg downloading. For 6 hours everything can very well happen and all of a sudden there is a box wifi that is used for intensive download, and there is disaster. If we have an antenna on an adjacent channel, the flows collapse, all data packets are lost and the response times explode.

We installed several antennas on different channels. If you have problems with an antenna, we advise you to try another antenna. In most cases this solves the problem. We regularly change channels to find the freest channels. There is another unlicensed frequency band available at wifi for some years in 5Ghz. All recent smartphone/Tablet/PC support it, but in amplified wifi like Badboy/Bullet/Wirie it does not yet exist. Only Nanostation M5 / Groove 52 (dual band).

5Ghz is still very little used in the area. So there is very little interference and we get very good flows throughout the day.

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