Comparison TP-LINK TL-WN822N vs TP-LINK TL-WN821N

The total number of antennas (of all types — see below) provided in the design of the device.

In modern Wi-Fi equipment, this indicator can be different: in addition to the simplest devices with 1 antenna, there are models where this number is 2, 3, 4 and even more. The point of using multiple antennas is twofold. Firstly, if there are several external devices per antenna, they have to share the bandwidth among themselves, and the actual communication speed for each subscriber drops accordingly. Secondly, such a design may also be required when communicating with one external device — to work with MU-MIMO technology (see below), which allows you to fully realize the capabilities of modern Wi-Fi standards.

Anyway, more antennas, usually, means a more advanced and functional device. On the other hand, this parameter significantly affects the cost; so specifically looking for equipment with numerous antennas makes sense mainly when the speed and stability of communication are critical.

Note that antennas intended for mobile communications may also be considered in this clause. So when choosing a model with support for mobile networks, it's ok to clarify this point.

— External. Outdoor antennas tend to be larger than indoor antennas, and they usually have swivel mounts that allow the rod to be placed in the optimal position, regardless of the position of the device itself. All this has a positive effect on signal strength. In addition, there are removable external antennas — if desired, they can be replaced with more powerful ones. The main disadvantage of this option can be called bulkiness.

— Internal. Antennas located inside the case are considered less advanced than external ones. In most cases, they are smaller, and the performance depends on the position of the device (although many manufacturers use technologies to compensate for this effect). At the same time, equipment with internal antennas has a neat appearance without unnecessary protruding parts.

— External / internal. The presence in the device at once of both types of antennas described above (in this case, there may be more than one of those and others). The presence of several antennas improves the quality of communication, but if they are all external, the device may turn out to be too bulky. Therefore, in some models of routers, a compromise is used: part of the antennas is hidden in the case, which has a positive effect on compactness and appearance.

The total number of antennas in the router that are responsible for communication in the 2.4 GHz band. For details about the number of antennas, see "Total antennas", about the range — "Frequency range".

Rated power of the Wi-Fi transmitter used in the device. If multiple bands are supported (see “Ranges of operation”) the power for different frequencies may be different, for such cases the maximum value is indicated here.

The total transmitting power provided by the device directly depends on this parameter. This power can be calculated by adding the transmitter power and the antenna gain (see above): for example, a 20 dBm transmitter coupled with a 5 dBi antenna results in a total power of 25 dBm (in the main antenna coverage area). For simple domestic use (for example, buying a router in a small apartment), such details are not required, but in the professional field it often becomes necessary to use wireless devices of a strictly defined power. Detailed recommendations on this matter for different situations can be found in special sources, but here we note that the total value of 26 dBm or more allows the device to be classified as equipment with a powerful transmitter. At the same time, such capabilities are not always required in fact: excessive power can create a lot of interference both for surrounding devices and for the transmitter itself (especially in urban and other similar conditions), as well as degrade the quality of the connection with low-power electronics. And for effective communication over a long distance, both the equipment itself and external devices must have the appropriate power (which is far from alway...s achievable). So, when choosing, you should not chase the maximum number of decibels, but take into account the recommendations for a particular case; in addition, a Wi-Fi amplifier or MESH system often turns out to be a good alternative to a powerful transmitter.