How to optimize your WiFi

Hello dear neighbors,
do you also have problems with the WLAN? Not enough range? Too slow? Unstable?
We Freifunker have a few tips.

The aim of the following text is to explain to you what the optimal settings for your WLAN are and why they are.

The right channel

The right channel is one of the most important factors. It influences both the quality of your WiFi and that of your neighbors.
The most common WiFi devices are those that use the IEEE 802.11b/g/n standard. These use the 2.4 GHz band. In Germany, 13 channels each 5 MHz wide are available in this band.

The 802.11b standard uses a width of 22 MHz and offers a maximum of 11 mbit gross. This standard should no longer be used today as it does not support modern encryption and is therefore insecure. We recommend switching off any compatibility mode and replacing devices that only support 802.11b with newer ones.

Newer 802.11g/n devices offer a higher transmission rate and use only 20 MHz width.Devices that use all or some of the same channels will interfere with each other. Partially overlapping channels interfere more than identical channels. The optimal channel allocation in Germany is 1-5-9-13. Please set your router to one of these 4 channels to avoid overlapping and minimize interference. Freifunk Pinneberg always operates on channel 9.
Some routers also have an automatic channel selection, but unfortunately this rarely leads to an optimal result. Make sure that the country settings are set to Germany or Europe and not US. There are only 11 channels in the USA, but 13 in Europe.

Summarized:
Use the channels 1-5-9-13, set width to 20 Mhz, turn off 802.11b support.

Sources of interference

WiFi can be disturbed by many things. The 2.4 GHz band is approved for general use, so there are many devices using it. Bluetooth also transmits on 2.4 GHz, as do some DECT telephones. Almost everything that transmits data uses the 2.4 GHz band.

In addition to devices that deliberately transmit, there are also devices that cause interference even though they themselves do not transmit. For example, poorly shielded microwave ovens, travos from ceiling lamps or even plasma televisions. Sometimes it helps not to place your own router directly next to such a device.

Antennas

In Germany, the maximum power allowed for transmission on the 2.4 GHz band is 100 mW. This power can also be expressed as 20 dBm. It's important to note that this isn't about the router's power consumption, but rather the maximum power radiated by the antenna. So, if you replace your antenna with one with more power, you'll have to reduce the router's power to avoid exceeding the limit. And antennas aren't physical miracles that generate energy. Higher transmission power in one direction always comes at the cost of lower transmission power in another direction. As long as you adhere to the legal requirements, you can't transmit further with better antennas. However, you can hear further! So, if both sides use highly directional antennas, ranges of several kilometers are possible outdoors.

In summary:
Either read up on the topic in detail or keep the original antennas.

Router position

The position of the router and the antennas has a significant influence on the connection quality. Reinforced concrete shields the signals almost completely. Metal reflects like a mirror. You should avoid hiding the router in the last corner. Reception is usually best where the router is clearly visible.

5 GHz Wi-Fi

802.11a/n/h/ac uses the 5 GHz band. This enables higher data rates and is also much less crowded than the 2.4 GHz band. However, 5 GHz signals are attenuated significantly more by walls or air, which is why the range is often significantly shorter. However, the shorter range can also be an advantage, as it reduces interference from neighbors' signals.
Since Wi-Fi is only a secondary user in the 5 GHz band, it must ensure that the primary users, primarily (weather) radar, are not interfered with. The rules here are correspondingly complex, which is why we are only providing a rough summary here.

Channels 36 to 64 inclusive may only be used in completely enclosed spaces. The maximum transmission power is 200 mW (23 dBm). Channels 100 to 140 may also be operated outdoors, even with a transmission power of up to 1000 mW (30 dBm). However, radar detection techniques (DFS) and Transmitter Power Control (TPC) are required. On the one hand, this makes 5 GHz devices significantly more expensive, but on the other hand, DFS can ensure that no data is transmitted. And since no radar can escape the DFS, manufacturers tend to set it to overly sensitive, sometimes even blocking channels where there is no radar at all. Those using modern devices can achieve good results with 5 GHz Wi-Fi. We recommend focusing on a 20 MHz bandwidth here as well to minimize interference. Overlap-free channels are then 36, 40, 44, 48, 52, 56, 60 and 64 (only indoor) and 100, 104, 108, 112, 116, 120 ,124, 128, 132, 136, 140 (also outdoor).

PowerLAN

With PowerLAN (sometimes also referred to as Powerline, PLC, or dLAN), data is transmitted via the electrical wiring in the house. These wires are usually unshielded and thus act like a large antenna. This can cause significant interference with other wireless systems.
This particularly affects frequencies between 1 and 100 MHz, which are used by radio and analog BOS radio (police/fire department), among others. In extreme cases, this can lead to the Federal Network Agency ringing the doorbell to ensure that these devices are no longer used. Contrary to typical manufacturer specifications, the signals do not necessarily stop at the electricity meter. Therefore, similar devices belonging to neighbors may be affected. Furthermore, similar to Wi-Fi, data can be intercepted. To protect your personal data, encryption helps, but unfortunately, only a few devices have adequately implemented it. We recommend avoiding the use of this technology.

Weiterführende Informationen

Wer noch etwas weiter in die Materie einsteigen möchte, findet hier externe Links mit weiteren Informationen.

Software tips

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