Comparison MikroTik HGO-antenna-OUT vs MikroTik ACSWIM

The installation method for which the antenna is nominally designed.

— External. Models designed for outdoor use. The main difference between such antennas and internal ones is an increased degree of protection, which allows you to endure precipitation, temperature changes, dust and other "troubles" associated with working outdoors. Another feature is that the outdoor antenna can be quite large, which, in turn, has a positive effect on performance. It is this installation method that is used by the most powerful and “long-range” models (although, of course, the matter is not limited to them). Theoretically, an external antenna can also be installed indoors, but in fact this is rarely justified: firstly, because of the mentioned bulkiness, and secondly, because of the signal characteristics due to the presence of walls.

— Internal. Models designed for indoor use. They differ from external ones in smaller sizes, as well as in the absence of special weather protection (which is why it is highly undesirable to use such an antenna outdoors, at least). The specifications of internal antennas are also generally lower; however, they are quite sufficient for their main purpose. Also note that such devices have a more elegant design — in order to fit into the interior of the room.

The type of polarization provided in the antenna.

Speaking very roughly and simply, a radio channel can be compared to a rope stretched from a transmitter to a receiver, and radio waves can be compared to the vibrations of this rope. Modern antennas for Wi-Fi and 3G are designed in such a way that these vibrations occur strictly in one plane — for example, up and down. Such waves are called polarized (more precisely, linearly polarized — other options are not relevant in this case). In the example above, the polarization is vertical, but there is also horizontal polarization, when the oscillations occur from side to side.

The general rule for choosing a Wi-Fi / 3G antenna for this parameter is as follows: the polarization must match the polarization of the antenna (antennas) with which you plan to communicate. Otherwise, communication efficiency will drop significantly — up to the complete impossibility of work. However, the main option today is vertical polarization — it is used by the vast majority of cellular and Wi-Fi equipment. "Purely horizontal" antennas are practically not produced, the ability to work in horizontal polarization is usually provided as an option; to do this, the antenna must be rotated by 90 ° around the horizontal axis relative to the standard position. Theoretically, this possibility is available for any antenna, but in fact it is worth turning only those models for which this possibility is...directly stated — they have the same horizontal and vertical HPBW (see below), and rotation does not affect the shape of the space covered.

Horizontal polarization can be useful when the air is loaded — it allows you to quite effectively separate the signal from other background (which is usually vertically polarized). However, this format of operation is rarely used, and, usually, for point-to-point connections, between two correspondingly rotated antennas.

There are a number of models that support the so-called dual polarization — when the signal is transmitted simultaneously in two polarization options. However, the need for such versatility is extremely rare, and it is expensive. Therefore, there are relatively few such antennas.

The effective angle spanned by the antenna in the horizontal plane.

Any antenna that is not omnidirectional radiates a signal in the form of a "beam", and unevenly: the power is highest in the middle of this beam and weakens as it moves towards the edges. The boundaries of HBPW are two opposite lines, on which the signal power is attenuated to half of the maximum. In other words, HBPW is a sector (in this case, horizontally) within which the signal from the antenna will not weaken by more than half and it will maintain acceptable performance.

Other things being equal, a more widely directional antenna will be more convenient in aiming at a target, and also more effective in difficult signal propagation conditions (for example, in dense buildings where it can come from different directions). A narrower focus, in turn, has a positive effect on the gain and, accordingly, the “range”.

The effective angle of coverage of the antenna in the vertical plane, technically — the angle within which the signal power will be at least 50% of the maximum.

For details about the meaning of this parameter, see "HPBW / hor." higher. Here we note that if the antenna is not tilted, then the middle of the covered sector (that is, the line where the signal is most powerful) runs horizontally. Therefore, if another device to be contacted is above or below the antenna, the latter will have to be tilted for maximum communication efficiency. However, absolutely accurate guidance may be required only when receiving a very weak signal on a narrowly directed antenna — in other cases, hitting the HPBW itself is quite enough.

The impedance of an antenna is the resistance that occurs when an alternating current is applied to it. In modern Wi-Fi and 3G antennas, this parameter is standard and is 50 ohms. The cable that connects the antenna to the router or modem must have the same wave impedance — otherwise its efficiency will drop sharply (for example, a standard 75 Ohm television cable gives almost a two-fold power loss). However, many models have their own cable of quite sufficient length for use in the standard format, and usually you only have to pay attention to the characteristic impedance if you need to lengthen the “native” wire.

The signal gain provided by the antenna.

In this case, we mean the gain relative to an perfect isotropic radiator — an antenna that uniformly radiates a radio signal in all directions in the form of spherical waves. Such amplification is carried out by narrowing the flow of radio waves, roughly speaking, by increasing their concentration in space (even omnidirectional antennas emit waves not in the form of a sphere, but in the form of a disk). In this case, the coefficient is measured by the maximum power, which is achieved in the centre of the radiation pattern. Note also that the decibel is used to denote this parameter (more precisely, dBi, decibel relative to the isotrope). This is a non-linear unit: for example, a difference of 3 dB corresponds to a difference of approximately 2 times, 10 dB — 10 times, 20 dB — 100 times, etc. There are tables and calculators that allow you to convert decibels to times.

All this means that the gain is a rather specific parameter, and when choosing its optimal value, consultation with special sources or a professional communications operator may be required. However, this is true primarily for specific situations — for example, installing a 3G antenna in a private house a few kilometers from the base station. The general rule is this: an increase in the gain has a positive effect on the communication range, however, it makes the antenna more susceptible to interference and, usuall...y, affects its dimensions and weight.

The type of connector, as well as its number, used to connect the antenna to a router, modem or other equipment.

— N-connector. A coaxial connector with a characteristic round shape, developed back in 1940, known primarily as a standard socket for connecting antennas to a TV. However, in Wi-Fi and 3G equipment, a 50 Ohm impedance connector is used — it has a thinner centre contact than the 75-ohm "television" one, despite the fact that otherwise both connectors are identical. This is not a problem if the antenna is connected to external network equipment with a “native” cable, however, when using third-party wires, care must be taken: when connecting different types of connectors, they may be damaged, despite the fact that the connectors themselves are not always marked. However, this is also not recommended for electrical reasons (see "Characteristic impedance").

— RP-TNC. A high-frequency connector that appeared somewhat later than the N-connector described above (in the late 1950s). Similar to it in size, it also has a coaxial design, but it is regularly made for a wave impedance of 50 Ohms, which made it convenient for Wi-Fi and 3G equipment. (There are also 75-ohm versions, but they are rare and have obvious differences from the standard ones).

— RP-SMA. A further development of coaxial high-frequency connectors created in the 1960s.... Like RP-TNC, it is standardly produced for a nominal resistance of 50 Ohms, but it is more miniature (almost 3 times smaller in diameter), which makes it well suited for compact routers and modems. At the same time, despite its small size, it provides a completely reliable and high-quality connection.

— MMCX. Coaxial antenna connector, which is small in size — the inner diameter of the socket is slightly more than 2.5 mm. Due to this, such connectors are widely used in various portable equipment. MMCX are designed for impedance of 50 ohms and frequency range of 0 – 6 GHz.

— TNC. The "original version" of the RP-TNC described above; appeared first, and later RP-TNC was created on its basis. Both interfaces are identical in size and general design of the connectors, but they have opposite polarity and a different distribution of contacts: in TNC, the “male” (male) contact is located on the plug, “mother” (female) is in the socket, in RP-TCN — vice versa. For a number of reasons, RP-TNC turned out to be more preferable for Wi-Fi and 3G equipment, and the original TNC was not widely used.

— FME. 50 ohm coaxial interface similar in size to RP-TNC but not identical. It supports frequencies up to 2.4 GHz, which is why it is found mainly in antennas for mobile communications and universal models.

— CRC9. Miniature coaxial interface, found mainly in 3G / LTE modems and antennas for them; however, it can also be installed in universal antennas. The connector diameter is only about 2 mm, which makes it easy to use in portable equipment. The cable under CRC9 often has an L-shaped plug to increase reliability.