Increasing WiFi range is important to enjoy a consistent signal across your network and it can be achieved with the help of a good antenna. There are different types of antennas available and we will go through them. We’ll also discuss how they work and what is required to set them up. While most users stick to the default antennas of their router, opting for an alternative WiFi antenna may be necessary if you want to improve the signal range. We will present the information that you need about antennas to be able to take full advantage of them in your network and fix any possible issues.
How do WiFi antennas work?
One of the most important elements of an antenna is frequency wavelength, but there are other aspects that also play a crucial role including channel width, frequency and spectrum. Using an antenna that is designed for the correct frequency band is key. A 5GHz signal doesn’t work with a 2.4GHz antenna and the same goes the other way around. There are three elements that an antenna brings to a radio transmitter: Polarity, Gain and Direction. Polarity is the electric field’s orientation, which is the transmission from the antenna. Gain refers to the amount of energy boosted by the Radio Frequency signal. Direction is the shape or angel of the transmission, which refers to the area covered.
Omnidirectional Antenna
There are two types of WiFi antennas: omnidirectional and directional. The first type of antennas are suitable for 360 degree operation that allows a vertical dipole to radiate and the signal is received just as well in all horizontal directions. WiFi antennas feature two frequency planes: Horizontal plane and Elevation plane. The horizontal plane is also known as H or Azimuth plane, while the Elevation plane is often called “E plane”.
An omnidirectional antenna works with signals in any directions and they are commonly used on WiFi routers since these devices need to support connections from different directions. In many devices you will find basic small omnidirectional antennas featuring what is known as “rubber duck” design, which is similar to what is used on walkie-talkies. In some cases, you may need better range and for that, it is advisable to opt for a directional antenna.
Directional antenna
Due to the fact that the power of the omnidirectional antenna has to be spread across 360 degrees, its gain in one direction is lower than directional antennas, which keep energy focused on a single direction. This makes them ideal for controlling the direction of the broadcast or to receive a distant broadcast. They are generally used to extend the WiFi range to difficult to reach areas of a building. There are multiple kinds of directional antennas such as Yagi, Parabolic, Flat Panel,and Centenna. Below you will find more about them.
Yagi antennas have limited coverage angle that generally reaches between 12 and 25 degrees of width. They are ideal for wireless point-to-point environments. Yagi antennas keep the signal narrow on both planes, which helps to fight interference. The disadvantage is that they are not very easy to adjust in order to reach optimal signal. Additionally, birds are likely to perch on Yagi antennas since they are horizontal.
Parabolic antennas are easy to identify due to their bowl shape. They bounce back the signal off the back reflector and focus it into one central point. They are usually implemented for point to point environments and offer similar coverage width and elevation to the Yagi antenna. The downside is that the dish is more likely to be affected by snow, ice and wind.
Flat panel antennas are best suited for corridors or particular areas of a building that require broad directional signal. Usually, flat panel WiFi antennas have a horizontal plane coverage angle of 35 to 120 degrees of width.
Centenna is a type of antenna that is generally used as the receiving end for client computers. The majority of users rely on them to replace the rubber duck design antennas of their wireless USB adapters. Centennas are convenient for travelling and they can be used to improve the signal when using WiFi hotspots. Centennas are cylinder-shaped and some users even make their own versions using cans and other similar objects.
Antenna Polarity
Correct polarity is crucial, no matter what kind of antenna you use. The antenna used for broadcasting and the one used for receiving should have the same polarity. A strong signal is essential for an effective performance. When it comes to signal quality, radio wave polarization is a key element. The physical position of the antenna determines the polarization. Omnidirectional antennas are polarized vertically, but if the antenna is turned sideways, it becomes horizontally polarized.
Antenna gain
The antenna gain determines the range and strength at which it can connect. When someone talks about the power of the antenna, it is likely that they are referring to the gain, which is measured in an unit called dBi. Gain tells you how efficient the antenna is in converting the transmit power into a radio wave that can be sent. On the receiving end, the gain measures the antenna’s performance when receiving the radio wave and then transforming it to electrical power.
dBi and dBm
While dBi and dBM can be difficult to understand, the main thing to remember is that what you want to reduce the amount of loss and keep as much gain as you can. Regardless of the power level you are referring to, gain and cable loss remain constant. Cable loss has an impact on antenna gain and it is associated with aspects that can reduce the gain, including length and diameter of the cable.
dBi is a measurement that is relative, this means that no matter what is the level of power, the dBi will not change. dBm is the ratio of decibels (dB) to milliwatts. The reference unit is exactly one milliwatt and one milliwatt is the absolute unite of measure. To convert watts to dBm, a complex formula is required, but essentially, 1 watt (1000mW) are 30dBm.
Cables for WiFi Antenna
Low-loss cable like LMR-400 is ideal for outdoor settings and runs over 4 feet long. For instance, for a 20 foot run, 19 feet of LMR-400 should be used for the main line, while the smaller LMR-100 cable works for 1 foot pigtail that features the connectors you require. The pigtail is likely to have N Female on one end and RP-SMA Male on the other side. The most common antenna connectors are N Female, N Male, RP-TNC Female. RP-TNC Male, SMA, RP-SMA Female and RP-SMA Male.
Outdoor WiFi antennas
If you need to set up an antenna outdoors, you will need a lightning arrester to protect the router or access point from electric surges in case of lightning strikes. It is advisable to opt for gas charged lightning arresters as they offer effective protection. In case of electrical surges, these arresters safely release excessive voltage to the ground. They are useful devices to prevent damages on your router, just make sure that they are correctly set up in the ground.
Conclusion
WiFi antennas support specific frequencies. The factors that play a crucial role on gettng the radio waves to and from the transmitter include polarity of the signal, direction of the antenna and gain of the antenna. You can increase the quality of the signal by matching polarity. You can get as much incoming and outgoing radio signal by reducing loss and keeping as much gain as you can. To be able to get maximum gain, you need to use low-loss cable and take measures like using gas-charged lightning arresters to ensure that your indoor equipment is secure in case of lightning strikes.
