Wi-Fi antennas are an essential element in building a reliable wireless network. They increase the network signal level and establish a reliable connection in the coverage area that they create. For organization local network omnidirectional antennas are used indoors for. If subscribers are at a distance, sector and directional antennas are used, the power of which is higher. The catalog contains types of antennas that will help you create a network in an apartment or establish a connection with a country house:
- omnidirectional antennas;
- sector antennas;
- directional antennas;
- internal antennas;
- external antennas.
What is a Wi-Fi Antenna for?
Before choosing the option you need, you should clearly determine the purpose of the antenna. When choosing an antenna for a Wi-Fi router, it is worth determining the purpose of use, frequency range and antenna coverage. The consultants of the online store will help you with this.
Organization of a reliable Wi-Fi zone? If you need uniform Wi-Fi coverage in an office or residential building, an access point with an omnidirectional antenna is suitable for this. To create a point-to-point or "bridge" connection, it is worth using external directional antennas that "hit" up to 50 km with the appropriate transmitter.
Why an online store site?
If you choose a Wi-Fi antenna and you have any questions, the site's online store consultants will help you choose a product, advise on prices and delivery. If the search takes place outside business hours, use " ". You will facilitate the process of choosing and buying the right product. We guarantee the performance and quality of the product at a reasonable price.
If you want to assemble a long-range WiFi antenna, then you should know about some of its features.
First and foremost, large antennas of 15 or 20 dBi (isotropic decibels) are power-limiting and don't need to be made even more powerful.
Here is a clear illustration of how, as the antenna power in dBi increases, its coverage area decreases.
So it turns out that with an increase in the distance of the antenna, the area of \u200b\u200bits coverage decreases significantly. At home, you will have to constantly catch a narrow band of signal coverage with a too powerful WiFi emitter. Get up from the couch or lie down on the floor, and the connection will immediately disappear.
That's why home routers have conventional 2dBi radiating antennas so they're most effective over short distances.
directional
Antennas at 9 dBi work only in a given direction (directional action) - they are useless in a room, they are better used for long-distance communication, in the yard, in the garage next to the house. A directional antenna will need to be adjusted during installation to transmit a clear signal in the desired direction.
Now to the question of the carrier frequency. Which antenna will work better at long range, at 2.4 or 5 GHz?
Now there are new routers operating at double the frequency of 5 GHz. Such routers are still new, they are good for high-speed data transfer. But the 5 GHz signal is not very good for long distances, as it decays faster than at 2.4 GHz.
Therefore, older 2.4 GHz routers will perform better in long-range mode than newer, faster 5 GHz routers.
Drawing of a double homemade biquadrate
The first samples of home-made WiFi signal distributors appeared back in 2005.
The best of these designs are bi-square, providing gain up to 11-12 dBi and double bi-square, having a slightly better result at 14 dBi.
According to user experience, the bi-square design is more suitable as a multifunctional radiator. Indeed, the advantage of this antenna is that with the inevitable compression of the radiation field, the signal opening angle remains wide enough to cover the entire area of \u200b\u200bthe apartment with proper installation.
All possible versions of the biquad antenna are easy to implement. 
Required Parts
- Metal reflector-piece of foil textolite 123x123 mm, foil sheet, CD, DVD compact disc, aluminum lid with tea can.
- Copper wire with a section of 2.5 mm.kv.
- A piece of coaxial cable, preferably with a wave impedance of 50 ohms.
- Plastic tubes - can be cut from a ballpoint pen, felt-tip pen, marker.
- A little hot glue.
- N-type connector - useful for convenient connection of the antenna.
Emitter manufacturing
For the 2.4 GHz frequency on which the transmitter is planned to be used, the ideal bi-square dimensions would be 30.5 mm. But still, we are not making a satellite dish, so some deviations in the size of the active element -30–31 mm are acceptable.
The question of the thickness of the wire also needs to be taken carefully. Given the selected frequency of 2.4 GHz, the copper core must be found exactly 1.8 mm thick (with a cross section of 2.5 mm2).
From the edge of the wire we measure the distance of 29 mm to the bend.
We make the next bend, controlling the outer size of 30–31 mm.
We make the following bends inward at a distance of 29 mm.
We check the most important parameter for the finished biquadrate -31 mm along the midline.
We solder the places for the future fastening of the coaxial cable leads.
Reflector
The main task of the iron screen behind the emitter is to reflect electromagnetic waves. Correctly reflected waves will superimpose their amplitudes on the vibrations just released by the active element. The resulting amplifying interference will make it possible to propagate electromagnetic waves from the antenna as far as possible.
To achieve useful interference, it is necessary to place the emitter at a distance of a multiple of a quarter of the wavelength from the reflector.
Distance from emitter to reflector for antennas biquadrate and double biquadrate we find as lambda / 10 - determined by the features of this design / 4.
Lambda is the wavelength equal to the speed of light in m/s divided by the frequency in Hz.
Wavelength at a frequency of 2.4 GHz - 0.125 m.
By multiplying the calculated value five times, we get optimal distance - 15.625 mm.
Reflector size affects the antenna gain in dBi. Optimal dimensions for a biquad screen - 123x123 mm or more, only in this case it is possible to achieve an amplification of 12 dBi.
The sizes of CDs and DVDs are clearly not enough for complete reflection, so biquad antennas built on them have a gain of only 8 dBi.
Below is an example of using a tea can lid as a reflector. The size of such a screen is also not enough, the antenna gain is less than expected.
Reflector shape should only be flat. Try also to find the plates as smooth as possible. Bends, scratches on the screen lead to the scattering of high-frequency waves, due to the violation of reflection in a given direction.
In the above example, the sides on the cover are clearly superfluous - they reduce the signal opening angle and create dissipated interference.
Once the reflector plate is ready, you have two ways to assemble the emitter on it.
- Install the copper tube by soldering.
To fix the double biquadrate, it was necessary to additionally make two small ballpoint pen stands.
- Fix everything on a plastic tube using hot glue.
We take a plastic box for discs for 25 pieces.
We cut off the central pin, leaving 18 mm in height.
We cut four slots in the plastic pin with a needle file or file.
We trim the slots equally in depth
We install a home-made frame on the spindle, check that its edges are at the same height from the bottom of the box - about 16 mm.
Solder the cable leads to the emitter frame.
Taking a glue gun, we fix the CD at the bottom of the box with plastic.
We continue to work with a glue gun, fix the emitter frame on the spindle.
On the back of the box, we fix the cable with hot glue.
Connecting to a router
Anyone with experience can easily solder to the pads on the circuit board inside the router.
Otherwise, be careful, thin tracks can come off the printed circuit board during long-term heating with a soldering iron.
You can connect to an already soldered piece of native antenna cable via an SMA connector. Buying any other N-type RF connector at your local electronics retailer should be no problem.
Antenna Tests
Tests have shown that an ideal bi-square gives a gain of about 11-12 dBi, which is up to 4 km of a directional signal.
The antenna from the CD gives 8 dBi, because it turns out to catch a WiFi signal at a distance of 2 km.
Double bi-square delivers 14dBi - a little over 6km.
The opening angle of antennas with a square radiator is about 60 degrees, which is quite enough for the courtyard of a private house.
About the range of WiFi antennas
From a native 2 dBi router antenna, a 2.4 GHz, 802.11n signal can extend up to 400 meters within line of sight. Signals of 2.4 GHz, old standards 802.11b, 802.11g propagate worse, having half the range compared to 802.11n.
Considering a WiFi antenna as an isotropic radiator - an ideal source that spreads electromagnetic energy evenly in all directions, you can be guided by the logarithmic formula for converting dBi into power gain.
Isotropic decibel (dBi) - antenna gain, defined as ten times the decimal algorithm of the ratio of the amplified electromagnetic signal to its original value.
AdBi = 10lg(A1/A0)
Converting dBi antennas into power gains.
| A,dBi | 30 | 20 | 18 | 16 | 15 | 14 | 13 | 12 | 10 | 9 | 6 | 5 | 3 | 2 | 1 |
| A1/A0 | 1000 | 100 | ≈64 | ≈40 | ≈32 | ≈25 | ≈20 | ≈16 | 10 | ≈8 | ≈4 | ≈3.2 | ≈2 | ≈1.6 | ≈1.26 |
Judging by the table, it is easy to conclude that a directional WiFi transmitter with a maximum allowable power of 20 dBi can propagate the signal to a distance of 25 km in the absence of obstacles.
A further increase in the power of the antenna is unreasonable; the signal will propagate in a too narrow disk-shaped zone.
volt-index.ru
Powerful do-it-yourself Wi-Fi antenna
It's easy to make and very powerful as a Wi-Fi antenna. With it, you can receive and transmit a Wi-Fi signal not only for hundreds of meters, but for several kilometers!
The cannon antenna resembles the look of a space blaster and, like this fantastic weapon, has a directed and very powerful action. 
This is a directional antenna. And it is this property that gives a large receiving distance due to the large concentration of the signal in one direction. 
Antenna drawing diagram
The drawing shows the dimensions between the antenna elements. Its resonant frequency is tuned to the middle of the Wi-Fi frequency of 2.4 GHz.
To make an antenna, you will need
- Long stud with nuts.
- Metal sheet, I took copper, as it is very easy to cut. In general, you can take tin from cans.
- WiFi Adapter. But you can connect to an existing router.
Making a powerful Wi-Fi antenna gun
Before proceeding with the manufacture of the antenna, you need to know that any deviation from given dimensions greatly degrade its performance. Therefore, everything must be done as accurately as possible.
We take a sheet of metal and roughly mark the centers of the diameters of the circles. Then we drill the center. For accuracy, a place before drilling is a core or we go through a thin drill, and then a thick one. As a result, the diameter of the hole should be slightly larger than the stud. 
Then we take a compass and draw circles on the metal. 
Cut out the square first. 
Then carefully cut out the circle. 
We got circles for the antenna. 
I took a long hairpin. I cut off the excess along the length of the antenna, taking into account the width of the nut. 
Here is the finished assembly kit. 
We assemble the antenna. Everything is very simple, like a designer in childhood. 
To control the dimensions, I recommend using a metal ruler, as it is more accurate. 
In the last two disks, you need to make holes for connecting the cable. 
We will make a connector with a cable from an old antenna from a router or adapter. 
Remove the top cover. 
Cut off the insulation. The antenna unhooked itself, because it was pressed in. 
Next, solder the metal cap. 
And the connection is ready. 
Ludim disks. Copper is great in this regard. Once I made such an antenna from the case of an old computer, so I had to tinker with acid there. 
We pass the cable through the hole of the last circle and solder the shielding winding to the disk. 
Now we pass the middle core into the hole of the second disk and solder it. 
The antenna is almost ready. I'll mount it on a camera mount. There will be such a home option. 
We fasten the Wi-Fi adapter to the output of the connector. 
You can attach it with electrical tape or tape to the bracket. 
I will put the antenna on the window and direct it to objects where there may be a signal. 
Wow, how many networks appeared. Although before I caught the signal only from my router. There are not many access points in our city. 
The result is amazing. 
Add-ons
To enhance the effect, I decided to install such a gun on the roof. But for this, I need to solder the usual shielded cable instead of the connector, which I use for a satellite dish. 
Drill the hole a little and finish the cable plug. 
We fix with tape. 
We put it on the roof, placing it on a pole. 
The number of networks exceeded all my expectations.
Result
The result was such that the same type of antenna can be connected without any problems at a distance of about 10 kilometers! And this is without any amplifiers and special equipment.
With the help of such a powerful Wi-Fi gun - antenna, you can transmit a signal to the garage, to work, to school, to the country house. All materials are available to absolutely everyone, and everything is done very simply.
More detailed instructions assembly can be found by watching the video below. It also shows wider tests of this powerful wifi antennas.
PS: If you are going to make an outdoor version, then for insulation and corrosion protection, it would be nice to paint the entire antenna with ordinary metal paint.
sdelaysam-svoimirukami.ru
The story of the creation of a 10 km link based on helical antennas
Andrey Kunakov (
mail: akunakov-at-rambler.ru
) sent a story about his experience creating Wi-Fi connections at a distance of 10 kilometers using self-made helix antennas. With his kind permission, we publish this material
How it was.
The task was to create a link between two points. The link was planned to be used for telemetry, and specifically for transmitting data from a remote seismic station to the center. The channel width was assumed to be only 19.6 kbps for telemetry and at least 1 megabits for on-demand data capture. After analyzing all kinds of iron, D-Link was chosen: firstly, you can find it in stores, and secondly, our service is developed.
Two D-Link DWL-3200AP Manageable Access Points were purchased for $197 each. Among other things, this access point supports the 802.3af Power over Ethernet (PoE) power over Ethernet cable standard, which has significantly reduced signal loss due to a very short high-frequency coaxial cable.
After that, the question of the passive part became. Unfortunately D-Link's native antennas are too expensive: a 21 dB antenna costs $260. I had to rummage on the Internet, from what I found, I liked the design of the spiral antenna the most.
Used materials
Calculations and production
The antenna was calculated using a calculator.
After that, the antenna was assembled according to one of the descriptions, an analogue of which can be found on this site.
According to calculations, the antenna gain at ideal conditions should be 19.6 dB, but different sources either confirm this technique or deny it.
It took 15 days for the first antenna, the tricky part was how to attach the pipe to the plug and the plug to the reflector, while maintaining the geometry of the coil with the wave transformer (foil triangle). And, by the way, unlike the Internet description, I did not use an N-type connector on the reflector, but simply soldered the central core of the cable to the wave transformer, which gave minus two connectors, which means lower losses on the connectors in general. It took 1 day for the second antenna.
Antennas in progress
As thermal containers, two plastic dishes for the microwave were purchased. The DWL-3200 was placed there. The antenna and access point were mounted together on a mast.
Antenna mounted on a mast together with an access point in a thermal container.
Installation
And finally, the installation of antennas: the visibility between the two points is not quite direct, houses and trees obscure, the distance is 10 km. The photos below show the points and direction of installation of the antennas.
The first antenna is mounted on a mast 7 meters high on the roof of a two-story building. The second is mounted on a mast 23 meters high.
Oddly enough, the antennas started working right away. Several attempts have been made to establish communication with various distances- 1000 meters, 2.4 km., 4 km, 10 km. In all cases, communication was established.
Unfortunately, I did not fix the signal-to-noise levels, but subjective parameters indicate 10-18% signal quality, the connection works at a speed of 2 megabits.
That's all, now we are making two 24-turn antennas with a thicker winding wire.
www.wifiantenna.org.ua
Powerful biquad WiFi antenna 2.4 GHz for a do-it-yourself router
Are you having trouble receiving a signal? Not satisfied with the quality of the antenna built into the router case? Then this article will definitely be useful. We have tried to write step by step instructions, describing in detail the process of making a Bi-Quad (biquad) WiFi antenna 2.4 Ghz with your own hands.
You will need:
- A sheet of tin, getinax or foil textolite for a reflector. Size - 10 × 14 cm. The dimensions of the reflector are not very critical and, if necessary, can be slightly reduced;
- Copper wire, 2.5 mm in diameter, or 4 mm;
- A protective cap from a bicycle or a plastic cap from some kind of tube for making a holder;
- Coaxial cable: RG58 can be used, but if the cable length is 2 meters or more, then it is better to take a high quality cable - Aircell, Ecoflex or similar.
The signal level of the future antenna directly depends on the quality of the parts and the accuracy of the assembly.
How to make a Wi-Fi antenna with your own hands
We begin work with the manufacture of a radio signal reflector. It will be 10 × 14 cm in size. We measure the required dimensions.
We measure the required dimensions.
We cut off the excess.
We find the middle on the sawn off sheet.
We measure the diameter of the cable and drill a hole in the plate. The hole should be slightly larger in diameter than the cable.
The holder for the biquad Wi-Fi antenna must be strictly 18 mm in height. Therefore, we cut off the excess.
We make cuts using a round needle file. The distance between the reflector and the antenna should be 15 mm.
We make a biquadrat from a piece of copper wire about 25 cm long and 2.5 mm in diameter, or 4 mm.
We bend the squares so that the distance from the middle to the middle of the wire is 30-31 mm.
We check the dimensions for compliance with the requirements.
It is necessary to solder the ends of the wire and tin the place of the future cable attachment.
Solder the cable.
The homemade WiFi antenna is almost ready, it remains to glue the holder to the reflector and insert the cable into the hole.
Glue the "glasses" to the holder with hot glue.
To prevent the structure from dangling, we also fix the cable on the reverse side with glue.
Well, a powerful antenna for a Wi-Fi router is ready. Now you need to unsolder the original antenna from the network card / router and solder your own in its place.
Confident reception.
Based on materials from the site: okroshka.nnm.ru
all-he.ru
Powerful do-it-yourself Wi-Fi signal antenna
I will show you how to assemble a very powerful Wi-Fi antenna that can receive a signal at a distance of many kilometers, but at the same time light and easy to assemble. Having crossed two popular antennas, a wave channel and a pouch antenna, I had the idea to create a Wi-Fi gun.
You can make this antenna from any sheet of metal. I used 0.3mm thick copper foil because it is easy to cut with scissors.
The details of our antenna will be mounted on a hairpin, we need to cut out 7 disks with a hole in the middle.
To do this, you need to place, punch or drill seven holes, and only then circulate the circle. If you do the opposite, then the drill may go to the side, but for us it is important that the hole is exactly in the middle.
We scratch out the circle according to the dimensions indicated in the diagram and cut out our disks.
Picture 1.
You need to do it as accurately as possible, the deviation is only a millimeter and it will not work like that. The thickness of the metal and the diameter of the stud have almost no effect on the operation of our blaster and can be anything. It turns out such circles (See Fig. 1) and after all the details are cut out, it remains for us to wind them onto the hairpin, observing the size of the gaps between them.
This irradiator is assembled easily, like a constructor. We install the second plate of our
blaster at a distance as indicated on our diagram - 30 millimeters, by tightening the nuts we select exactly our 30 millimeters.
On the last two disks you need to make a hole for the wire. Our blaster is ready. Now it remains to connect it to our device. At the beginning, it will be a USB modem, then we will connect it to a smartphone and, finally, to a router in order to distribute the Internet through our WI-FI gun.
To connect to a Wi-Fi whistle, you need to carefully disassemble the antenna so as not to damage the wire. We tin the soldering points and solder the wire to the extreme large disk, and the central core to the next one after it. We mount our gun on the bracket so that it is convenient to aim at the victim's router.
The gun catches the net even at a distance of 500 meters. Wi-Fi gun materials are not expensive and available to everyone.
WiFi antennas for 2, 5, 10, 15 km and more.
Among Ukrainian providers, Ubiquiti and MikroTik wireless equipment is in constant demand due to the optimal ratio of price, quality and performance. There is only one small difficulty: the product range of both manufacturers is quite extensive, and it is not always easy to figure out which access points and antennas are best to buy. Our managers constantly receive requests like:
- Pick up WiFi antennas for me at 2 km for the base station.
- What equipment can be used to build a WiFi bridge for 15 km?
- What WiFi antennas would you recommend for a 5km bridge with good throughput?
Several years ago, we already published an article with Ubiquiti recommendations for selecting equipment for links of various ranges. But during this time he left new standard WiFi 802.11ac, many new models have appeared with and without its support, so there was a need for a new selection.
Let's make a reservation right away: in the future we will talk about the choice of access points, that is, devices that combine an antenna and a radio module, or sets from an access point and attached to it external antenna. However, many people call access points "WiFi antennas", which is not entirely true, but quite common, so we will use this designation too.
The given solutions are designed for basic conditions. Actual results will depend on environment, interference, path, EIRP limits and other factors.
Ubiquiti - WiFi antennas for 2, 5, 15 km for bridges
A PtP link (Point-to-Point, "point-to-point"), or a bridge, connects two devices located in different places with each other. As a rule, the bridge is built at a distance of 150-200 meters to several tens of kilometers.
WiFi antennas for bridges up to 5 km
Nanostation Loco M. Also suitable for short distances (up to 3 km in our experience). PtP solution of the minimum cost, but the supported standard is only 802.11n, respectively, the throughput is lower.
Nanostation M. Very popular WiFi antennas (access points) for short distances, often used for video surveillance due to the presence of an additional Ethernet port. But still the same 802.11n standard.
WiFi antennas for bridges 5-15 km
- LiteBeam 5 AC-23 : Ubiquiti recommended client hardware that also works for bridges. Superior performance thanks to airMax AC standard, throughput up to 450 Mbps.
- powerbeam 5 AC. These WiFi antennas are recommended by the manufacturer as client equipment for long distance links, or for medium distance bridges (5, 10, 15 km). Superior performance with airMax AC standard, throughput up to 450 Mbps.
- powerbeam 5 ACISO. Almost completely repeats PowerBeam 5AC, but thanks to the insulator gives good results in a noisy environment.
- LiteBeam M. This WiFi antenna is ideal for those cases where there is no need for high bandwidth, where connectivity itself, wind load, low price more important than performance. The device does not support MIMO, it has one polarization, the 802.11n standard, so the channel speed is only 150 Mbps, the real throughput is correspondingly less.
- Power Beam M: Optimal price/performance ratio for medium distance links, 802.11n standard.
WiFi antennas for bridges over 15 km
airFiber 5 X + AF-5 G(directednarrow beam WiFi antennas). This is a carrier grade kit for long distance bridges, data transmission over distances of 200+ km is possible. Efficient use of the spectrum, providing throughput up to 620 Mbps (using a channel width of 50MHz).
Rocket 5 AC + Rocket DishL.W. An excellent set of highly directional WiFi antenna and access point. The choice for high performance links over long distances. TCP/IP throughput up to 450 Mbps (using 80MHz channel width). Link range — 100+ km
High performance backbone channels
AirFiber 24 HD. Excellent performance. AirFiber 24HD delivers up to 2 Gb/s real throughput over distances of approximately 2 km in the 24 GHz band, and up to 1.4 Gb/s on links up to 9 km. However, under certain circumstances, you can use the device at distances up to 20 km.
AirFiber 24. AirFiber 24 delivers up to 1.4 Gbps of real throughput over distances of approximately 5 km in the 24 GHz band. You can use the device at distances up to 13 km, only the throughput will be less.
AirFiber 5/5 U: Excellent throughput in the 5 GHz band. These RRLs provide up to 1.2 Gbps throughput. The device can be used at distances up to 100 km.
Ubiquiti base stations
Point-to-Multipoint links (PtMP, "point-to-multipoint") is a connection of three or more devices located in different places, using 1 base station (access point) and several CPE devices (client stations) that are connected to the point wireless link access.
The performance of a point-to-multipoint connection depends on both the base station and the client devices. Thus, if you want to provide data transmission over long distances, you need to choose the right base station and the right CPE for each specific case.
Base stations are usually located on top of towers, buildings, or on an antenna mast. The installation height determines the maximum coverage. When designing a base station, it is optimal to choose WiFi antennas with the narrowest possible coverage sector. Beam width should be as small as possible to cover the desired area. Larger beamwidth antennas covering a larger area and reaching more stations will also be more sensitive to interference, resulting in reduced performance and scalability.
Base station for 60 clients for short distances
Ideal for beginner providers in low interference areas.
Rocket M with OMNI omnidirectional antenna. Such a WiFi base station will pull up to 60+ concurrent connected clients if all devices support airMAX. Very sensitive to interference, only recommended for rural areas.
Base stations for 100, 200 or more clients with high performance
Rocket 5AC PRISM with airMax AC Sector Antennas. This is a carrier class WiFi kit for the highest performance base stations with dense client locations. For example, we install eight such WiFi antennas (access point + external sector antenna) on 1 mast with a beam width of 45 ° for circular coverage and get 800+ connections per mast. The devices use airPRISM technology, which greatly reduces adjacent noise.
Rocket 5AC Lite and Titanium Sector Antennas. High performance solution for medium density areas. Antenna beamwidth varies (60-120°) for scalability. 500+ client stations can be connected to one system of several Rocket and WiFi antennas. Uses latest technology airMax AC.
Ubiquiti Client Access Points (CPEs)
WiFi antennas up to 3 km
NanoBeam 5AC-16. Inexpensive WiFi antenna (access point), short range, the advantage is very compact dimensions and stylish design. Suitable for clients who value aesthetics.
NanoBeam 5AC-19: Slightly longer range compared to NanoBeam 5AC-16, better antenna directivity.
WiFi antennas up to 7 km
LiteBeam 5AC-23: low cost CPE, narrow beam, MIMO support. Recommended by Ubiquiti as the new industry standard for customer equipment with airMax AC.
Power Beam 5AC-300/400 A: Narrow beam CPE, long range and low noise.
WiFi antennas for long distance customers (over 7 km)
Power Beam 5AC-500/620: Higher power devices, high degree antenna directivity, long range and low noise, aesthetic.
Rocket 5AC-Lite/PTMP/PTP with RocketDish LW antennas: The most efficient WiFi kit, although it is more expensive than integrated designs and the design may seem unsightly. For better signal isolation on the antennas, ISOBEAM caps can be purchased separately. PTMP and PTP models support the latest airPRISM technology to reduce adjacent channel interference.
Important: Devices for long distances can also be used for short distances. For example, the PowerBeam M is likely to outperform the Nanostation Loco M at short distances due to the properties of the antenna.
Therefore, if several WiFi antennas are suitable for you, always use a more long-range and powerful one - this way you are guaranteed to get a stable link with good bandwidth.
Our opinion
We were a bit surprised that for bridges, Ubiquiti does not recommend regular (non-802.11ac) Rocket M access points with RocketDish antennas - a frequent choice of our customers. Most likely, because the 802.11n standard is already considered unpromising.
In addition, to base stations on the 802.11n standard, we also recommend client access points Nanostation loco M5, M2 - up to 1 km, Nanostation M5, M2 - up to 5 km. These are very popular and inexpensive solutions.
lantorg.com
Simple Omnidirectional 3G 4G Wi-Fi Antenna
Now in amateur radio practice, antennas for amplifying 3G, 4G, Wi-Fi signals of the "Bikvadrat" type are very common. 
Such an antenna has a directional action, which may not always be an advantage, but even a disadvantage. An example is this: you need to amplify the signal of your router so that you can catch it in any part of your house. If you use a directional antenna, then the signal will most likely be well available only in the field of action of this antenna. Surely this will be only one room where she will be directed. It is good to use such an antenna only for long-distance communication, provided that you know where to point it.
To strengthen your WI-FI signal in all directions, an antenna will do, which I will show you. It is close to the whip antenna in its directivity characteristics, with the exception of greater sensitivity.
By structure, this is actually the same bi-square, only twice directed in opposite directions. Plus, this antenna is many times simpler than the classic biquad, since it has neither a rack nor a reflector.
How to calculate the antenna?
Just please don't be scared, fifth grade math. We only need to calculate one arm, since the antenna is square. But first you need to find out at what frequency we will make the antenna. Personally, in the example I will do under WI-FI. It is known that the WI-FI frequency is approximately 2.4 GHz or 2400 MHz (there is also an even more modern Wi-Fi - 5500 MHz). If you do under 3G - 2100 MHz, and 4G (YOTA) - 2600 MHz.
We take the speed of propagation of radio waves (300,000 km / s) and divide by the desired frequency (2400 MHz) in kilohertz.
300.000/2.400.000 = 0.125 m
This is the wavelength we got. Now divide by four and get the length of the arm of the square.
0.125 / 4 will approximately turn out 0.0315 m. Convert to millimeters for convenience and get 31.5 mm.
Making a simple do-it-yourself Wi-Fi antenna
Brem thick wire 2-3 mm thick. And a template cut from a piece of aluminum. You can of course do without it, but it's easier with it. 
We bend two loops from one wire and two from the other. The gap should be between the squares. 
Then, with masking tape, I temporarily fix the squares crosswise to make it easier to solder. And I solder the middle from above so that the structure becomes rigid. 
Now you need to take a thick piece of cable with a connector (you can take it from the same whip antenna). 
Insert inside the antenna and solder. The middle wire to the top, and the lower shoulders of the squares to the common one. 
The antenna is ready. To finish, you can fill the solder joint with hot glue and paint.
Antenna testing
Compare the signal strength with the whip antenna that originally came with the router. 
Whip Antenna: 
Now in comparison. The first pin, and then our omnidirectional bi-square.
The helix antenna, invented in the late forties by John Kraus (W8JK), can be called the simplest antenna implementation imaginable, especially for frequencies in the 2-5 GHz range. This design is very simple, practical and at the same time reliable. This article describes how to make your own helical antenna for frequencies around 2.4 GHz which can be used, for example, for high speed RF (S5-PSK, 1.288 Mbps), 2.4 GHz wireless networks and amateur satellite (AO40). The development of wireless network equipment makes it easy to obtain high-speed radio access using the IEEE 802.11b standard (also known as Wi-Fi).
Brief overview of the theory
A helical antenna can be described as a spring with a number of turns N with reflector. Circumference ( C) of the coil is approximately the wavelength ( l), and the distance ( d) between turns is approximately 0.25C. Reflector size ( R) is C or l and can be round or square. The design of the radiating element causes circular polarization (CP), which can be either right-handed or left-handed (R and L, respectively), depending on how the spiral is wound. In order to transmit maximum energy, both sides of the connection must have the same polarization direction, unless a passive radio wave reflector is used in the signal path.
Gain ( G) of the antenna with respect to isotropy (dBi) can be calculated using the following formula:
G = 11.8 + 10 * log ((C/l)^2 * N * d) dBi (1)
According to the findings of Dr. According to Dr. Darrel Emerson, AA7FV of the National Radio Astronomy Observatory, the 4-5 dB result, also known as the Kraus formula, is too optimistic. Dr. Dr. Ray Cross (WK0O) analyzed the results of Emerson's study in the ASAP Antenna Analysis Program.
Characteristic impedance (impedance) ( Z) of the resulting transmission line should be empirically described by the formula
Z = 140 * (C/l) Ohm (2)
2.43 GHz implementation (aka S-band, ISM band, 13 cm amateur band)
l = (0.3/2.43) = 0.1234567 m (12.34 cm) (3)
Turn diameter (D) = (l/pi) = 39.3 mm (4)
A standard sewer plastic pipe with an outer diameter of 40 mm is an excellent solution for us and is easily available at DIY stores or any plumber :) The spiral can be wound from standard copper wire, which is used in the household for 220 V circuits alternating current. This wire has a colored PVC insulation and a copper core with a diameter of 1.5 mm. Winding the pipe with wire will give a resulting diameter D = 42 mm due to the thickness of the insulation.
D = 42 mm, C = 42*pi = 132 mm (which is 1.07 l) (5)
d = 0.25C = 0.25*132 = 33 mm (6)
For distances from 100 m to 2.5 km within line of sight, 12 turns (N = 12) is sufficient. Therefore, the length of the pipe will be about 40 cm (3.24 l). Wrap the wire around the pipe and glue it with PVC or any other adhesive containing tetrahydrofuran (THF). This will give a very strong wind around the pipe, as shown in Figure 1 below.
Picture 1. Used materials with dimensions.
Antenna Impedance:
Z = 140 * (C/l) = 140*((42*pi)/123.4) = 150 Ohm (7)
requires network compliance to use standard 50 ohm UHF/SHF coax and connectors.
Usually a 1/4 wave plug with resistance is used ( Zs)
Zs = sqrt(Z1*Z2) = sqrt(50*150) = 87 ohm (8)
Due to the helical design, this corresponds to 1/4 turn. However, from a mechanical point of view, given the need to take care of water resistance if the antenna is used outdoors, there are better methods to achieve resistance with a 50 ohm coil. The first thought was to empirically increase d for the first and second turns and achieve the desired value by trial and error, measuring the result using a directional coupler and a signal generator. After a short search on the Internet, spirals were put on, which were coordinated in this way, but unexpectedly, the page of Jason Hecker was found (Jason Hecker). He did use an elegant matching solution using a copper spatula according to the ARRL Handbook. So kudos to ARRL and Jason, his dimensions were used for the antenna. To be honest, this page practically copies his page, except that the spiral is wound in the opposite direction :)).
Figures 2a and 2b. Idea, dimensions and installation of the matcher. The hypotenuse of the triangle must be a continuation of the wire.
Now you need to solder the matcher to the coil, glue them and get ready to connect with the cap, as shown in Fig. 3.
Figure 3 Almost finished spiral antenna.
Ready! (Fig. 4)
Figure 4 Completed 12-turn 2.4 GHz helical antenna, G = 17.5 dBi or 13.4 dBi (respectively according to Kraus or Emerson).
The characteristics of the antenna have been measured. The results are shown in Fig. 5a and 5b:
Figure 5a. Return Loss (dB) 2300 to 2500 MHz
Figure 5b. Smith Chart 2300-2500 MHz
Figure 6a Measurement setup
Figure 6b Hourly Helical Antenna and Rohde & Schwarz analyzer
And finally, the spiral antenna in action...
Figure 7a Radiates to my LAP (Local Access Point ;-)
Figure 7b Bottom view
During flights, crashes (accidents) periodically occur and it happens that the fragile antennas of the 2.4 GHz quadrocopter receiver are damaged, for example, from hitting a hard surface or from hitting the antennas on the propellers. Do not rush to buy a new receiver or new antennas (although you still need to buy spare ones), such antennas can be repaired.
2.4GHz Antenna Structure
A typical quadcopter receiver antenna often consists of a monopole antenna in a coax cable.
The first layer of such an antenna is a plastic braid, then a shielded metal braid in the form of a mesh, it prevents interference (noise), and, in fact, the antenna cable itself.
Removing the plastic and screen braids, you will see active element- an antenna.
Antenna length for different receivers
The 1/4 wavelength of 2.4GHz is 31.23mm, but why do some receivers have different antenna lengths? We have measured antennas on several different Frsky RX:
- R-XSR - 23.5mm
- X4R-SB - 33.25mm
- XSR - 26mm
- XM+ - 23mm
As mentioned above, an antenna that is too short or too long changes its resistance and inductance, and this shifts the resonant frequency. But in fact, you can adjust the capacitance and inductance by adding an inductor or capacitor to the root of the antenna, and theoretically, you can tune the antenna to any desired length.
This may be why some receivers have longer or shorter antennas than 31mm.
Antenna braid length
Another theory says that the length of the shield braid also has great importance and may affect the performance of the antenna. I'm not familiar with the concept, but I'm told that by leaving the shielded portion of the antenna at a few quarter wavelengths, the performance of the antenna can be improved.
When repairing an antenna, it is usually necessary to shorten the braided shield to an odd length, which can ruin the antenna's 1/4 wave tuning and cause various interference. An interesting observation is that the XSR receiver has a 3/4 wavelength shielded wire, which is not the case with other Frsky receivers.
When trying to justify the theory with the length of the shielding braid, nothing was confirmed. In my experience, no noticeable change occurred when trying to change the length of this braid. On one of my quadcopters, I left the braid (shielding) just 2cm from the end of the antenna, but it worked just as well as before (within 800m). Perhaps you had to fly further to feel the difference.
If you want to fly safely, it is best to keep an eye on the length of the original antenna and shorten it to the same level as the original after replacement.
Spare Antennas
If the antennas are damaged, I first try to repair them, but if interference or signal loss starts to appear, I simply change the old one to a new one to avoid problems.
Please note that in last episode Frsky receivers, they started using a smaller version of the IPEX connector called "IPEX 4th generation". Be extremely careful when purchasing replacement antennas for your Frsky receivers and make no mistake.