FPV antenna is the deciding factor that determines the range and signal strength of your FPV system. This guide will explain the basics of 5.8Ghz antennas used on mini quad VTX and VRX, and hopefully it will help you choose the best FPV antenna.
To learn more about FPV, make sure to check out our complete guide to FPV Drones.
The Best FPV Antennas for Mini Quad
Looking for antennas for the DJI FPV System? I’ll talk about that in another post. The following antennas recommendations are for the analog system, but of course they’d work just fine for DJI as well as long as you get the polarization correct, since they are both operate on 5.8GHz.
Omni Antennas (Best Value)
The Xilo AXII is made by GetFPV, a good budget FPV antenna. The best thing is that it comes in all sort of connectors (SMA, RP-SMA, MMCX, and UFL), different types of coaxial cable (hard and flexible) and polarizations (RHCP and LHCP) to suit your needs.
The Rush Cherry is a decent budget antenna. It has a strong case which protects the antenna in hard crashes.
|Rush Cherry||. |
The Foxeer Lollipop might not offer the best performance, but they do have good enough quality for those who are on a budget to replace the stock dipole. These antennas are very durable thanks to the thick plastic housing.
|Lollipop (VRX)||RDQ |
The pagoda antenna is a simple yet effective design. The affordable material and easy assembly allows makes them very cheap to make, you can usually find them priced around $5 to $10 each, making it one of the best value antenna out there. However without proper housing and protection, they are very easy to break in a crash, so if you can afford a bit more, I would recommend getting one of the above antennas instead.
There are different manufacturers of Pagoda antenna, such as Lumenier, MenaceRC, Emax, Farview and Realacc. They all have basically the same design, main difference is build quality.
Omni Antennas (Top Of The Line)
Unlike the classic cloverleaf and skew planar wheel, the TBS Triumph Pro is very compact and protected in a sealed plastic case, makes it very durable. It claims to have one of the most impressive axial ratios (0.99), which means it has really good multipath interference rejection.
|Triumph Pro||Amazon |
The Lumenier AXII 2 by GetFPV is also a very small and strong antenna. The unique design provides uniform signal coverage, giving you equally good signal when flying behind yourself. These are available in many variations: MMCX, UFL, SMA, different stem lengths, enough to cover most if not all of your needs.
|Lumenier AXII 2||Banggood |
Directional Antennas (Cheap Worth Having)
The Menace Pico-Patch is a very compact and affordable directional patch antenna with wide signal coverage, delivers decent performance, great for FPV drones. Check out my review of the Pico-Patch
|Menace PicoPatch||Banggood |
Directional Antennas (Top of the Line)
This is the antenna to go for if you want a high gain directional antenna for long range, it provides a 10dB gain and yet giving you 120 beam-width.
|TrueRC X-Air||Amazon |
Another compact directional antenna that doesn’t look bulky on your slimline FPV goggles. Compared to the X-Air, the AXII Patch has lower gain, but wider signal reception.
|AXII Patch||RDQ |
What is FPV Antenna
An antenna is a piece of wire, or pieces of wire that convert electrical power into electromagnetic waves. The receiving antenna converts the electromagnetic waves back into electrical power.
In FPV, antennas (or antennae) enable wireless communication between the video transmitter (VTX) and receiver (VRX). Antennas in your FPV system are critical elements that determine the range and signal quality.
FPV Antenna Anatomy
Every antenna consists of the same basic parts regardless design or external appearance.
- Active Element – conductive material that transfers and receives radio wave signal in the air
- Coaxial Cable – a special shielded cable that carries signal from the connector to the antenna element without emitting radio signals. They are used to extend the length of the antenna, and often are made of rigid material so it can be bent to any desired angle. Coaxial cables are not necessary if the connector is directly connected to the element
- Connector – used to connect the antenna to a video transmitter or receiver.
FPV antenna elements are made of fragile copper wires or other conductive material, therefore it’s common to see antennas come in plastic protective housing. These housing or cases do not weaken the signal and provides support for the antenna in crashes.
Antenna Polarization – Linear or Circular
Antenna polarization is a classification of FPV antennas. There are two types:
- linearly polarized antennas (LP)
- circularly polarized antennas (CP)
What’s Linear Polarized Antenna?
Linear Polarization is used in some of the most basic antennas, such as the stock dipole antennas that comes with your VTX and VRX, or even in your home WiFi. Here’s an example of linearly polarized antennas:
What’s Circular Polarized Antenna?
Here are some examples, Skew-Planar Wheel, Cloverleaf, and helical antennas are all common circular polarized antennas.
In circular polarization, signal are transmitted on both horizontal and vertical planes with 90 degree phase shift that looks like a spinning corkscrew.
Linear or Circular, which Polarization is Better for FPV?
In a nutshell, circular polarized antennas are more suited for FPV drones for these reasons:
- Linear polarized antennas are much more sensitive to multi-pathing interference compared to CP antenna
- The range of LP antennas are greatly affected by antenna alignment, and it’s almost impossible to maintain good antenna alignment on a quadcopter all the time as it’s constantly rotating around all axes
Here’s the long version.
Linear polarized antennas are widely used due to its structural simplicity, which can be as simple as a piece of wire. The antennas tend to be smaller, lighter, cheaper and easier to make.
In general, linear polarization is a good choice for long range as all the energy is focused on a single plane. However, the range advantage is seldom realized due to multipath interference which we will discuss shortly.
In order to get the best reception, both transmitting and receiving ends should use linear polarized antennas, and they have to be aligned to ensure maximum radiation overlap. This is why linear polarized antennas are not popular in FPV, because FPV drones are constantly rotating around all 3 axes, it’s almost impossible to always have perfect alignment. For example when the transmitter and receiver antennas are at 90 degrees to each other, it would have the least amount of signal overlap which results in over 20dB loss in signal strength (over 90% reduction in range) and it’s referred to as cross polarization. LP antennas perhaps are more suited for RC planes, cars, boats etc.
On the other hand, circular polarized signal always overlap no matter what orientation or angle your FPV drone is at relative to your receiving antenna (no signal loss regardless the antennas alignment is). For this reason circular polarized antennas are the standard for FPV drones.
Another advantage of circular polarized antennas is their ability to reject multipath interference. Multi-pathing is a form of interference/noise in your analog video feed, often appears as random color changes, static, scrambled image and drop-outs. It happens when the signal is bounces off object (such as walls and ground), gets distorted with phase delay and it interferes with the main signal.
For general FPV drone flying, it’s recommended to use CP antennas. However, some pilots might prefer specially made LP antennas, because they can be made smaller, lighter, and more durable, despite of the worse RF performance.
When to use CP antennas
- When flying close to large objects such as trees, buildings, or in enclosed environment such as car parks and stadiums where there will be considerable amount of multipathing interference
- Acrobatic flying where the aircraft orientation and angle are constantly changing
- Low altitude flying (proximity flying)
When to use LP antennas
- Steady straight line flying without much roll and pitch movement
- When antenna size, weight and durability are the most important consideration
Using LP and CP Antenna Together
You can mix linearly polarized antenna and circularly polarized antennas in your FPV system, at the cost of some signal loss.
It’s not unheard of for some racers to use a dipole antenna on the drone for weight saving and durability while using a circular antenna on the video receiver. You will suffer from a signal loss of about 3dB (30%), but it’s not that bad for short range flying such as racing. And RHCP/LHCP doesn’t matter in this case. But it’s still better than the worse situation when only using only linear polarized antennas on both ends, where the maximum reduction in signal is 97% (30dB). It’s a compromise between performance and durability.
For ordinary FPV polits, I still recommend using only CP antennas.
Differences between LHCP and RHCP
Circular polarized antennas are either left-hand (LHCP) or right-hand (RHCP). Transmitter and receiver should have matching antennas otherwise it could result in significant signal loss. If you mix LHCP and RHCP antennas, they will still work but your range is greatly reduced.
This is because LHCP antenna rejects signal from RHCP antenna and vice versa. How much it rejects depends on the Axial Ratio of the antennas.
CP antennas can benefit from this property against multipathing. Every time a CP signal bounces off object it changes its polarization direction. And LHCP antenna rejects RHCP signal and vice versa (cross polarization). Also when one pilot is using LHCP antennas and the other using RHCP, there will be less interference between them.
Therefore you are supposed to use the same type of antenna on both receiver and transmitter. If you mix LHCP and RHCP you will suffer from significant signal loss.
For pilots flying in a group, it’s best to have both LHCP and RHCP antennas for flexibility. If you are just flying alone most of the time, then this doesn’t really matter, both LHCP and RHCP have the same performance. RHCP antennas are more common for analog FPV system, while LHCP is more common for digital FPV systems such as DJI and Avatar.
Directional and Omni-directional Antennas
Another classification of FPV antennas is directionality:
As you could guess from the names, omni-directional antennas radiate their radio waves equally in all directions, while directional antennas focus their radio waves to one direction.
One classic analogy is bulb vs torch, where the bulb is Omnidirectional and the torch is directional. If both light sources are operating at the same power, torch can reach further but in the expense of narrower beam width.
Directional antennas can be linear polarized or circularly polarized, same as omni-directional antennas.
Omnidirectional antennas are great for every-day flying, and it provides good signal coverage all around the pilot. Try to avoid using only directional antennas so you don’t have to constantly turning yourself to face directly towards your copter.
However directional antennas are often used on diversity receivers, where it can be paired with an omni-directional, or multiple directional antennas to cover all the necessary angles.
Diversity receiver can receive two signals from two antennas instead of just one, and it can then choose to display the stronger signal.
For example, if you have a diversity setup with a CP antenna and a helical antenna, the receiver will switch to the helical antenna when flying in front and to the CP antenna when flying behind.
Antenna Performance Measurements
There are many antenna performance measurements regarding FPV antenna design, such as:
- Radiation Pattern
- Axial ratio
- Tuned Frequency and bandwidth – what frequency is the antenna tuned to, and the range of working frequency
I mainly look at the first four factors when choosing my antennas. Anyway, as long as you are buying your equipment from a name brand you shouldn’t worry too much about it. In my opinion we are not flying a rocket for NASA and there is no need to cause headache for yourself in this case :)
But if you want to find out more about these concepts, both antenna-theory.com and wikipedia are great resources for learning about antennas. In the following sections I will try to briefly explain what these terms mean.
Gain is an indicator of directional antenna’s range and angle of coverage. Higher gain generally means further range but narrower beam width. Antenna gain can alter radiation pattern as we will see in a moment.
Tutorial: How antenna gain affects range?
Radiation pattern (radiation chart) shows the shape of the radiation emitted by the antenna. These charts can tell where the weak spots are and how likely it is to lose signal.
Here are some examples to help you visualize the the signal coverage patterns.
A 0dB gain antenna is truly omni-directional that has a nearly perfect spherical radiation pattern.
However omni-directional antennas in real life usually has signal loss on the top and bottom, and the radiation pattern would look more like a doughnut in 3D. In a two-dimensional view, it forms a figure-of-eight pattern in the vertical plane, and a circle in horizontal plane.
Here is the radiation pattern for an 8dB gain patch antenna. Notice the narrow beam width in both vertical and horizontal planes.
Low DB gain might seem a bit less appealing in terms of range, but it can offer more reliable performance thanks to the more spherical radiation pattern, you can get reasonably strong signals even by pointing the antenna straight at the receiver.
In reality there is no perfect circular polarized antenna. For example, a RHCP antenna might output 90% of RHCP signal with 10% LHCP signal. So there might still be interference even if you were doing everything perfectly. And Axial Ratio is used to measure this antenna property.
In practical FPV flying terms, this is the measurement of how susceptible the antenna is to multipath interference. Antennas with better capabilities of rejecting multipathing makes it easier to fly in areas with lots of concrete and metal.
Antennas with the axial ratio closer to 1, the better.
Frequency and Bandwidth
Antennas are tuned for a specific frequency, for example, the length of a dipole antenna determines the frequency it’s tuned to. The antenna would have the best performance when transmitting and receiving at this frequency.
If you transmit or receive at a slightly higher or lower frequency, the antenna would still have acceptable performance, and this “acceptable range” is the bandwidth. Outside of the bandwidth, signal strength is greatly reduced or even rejected.
You should understand what frequency your antenna is tuned for, and what the bandwidth is, in order to select the most effective channel/frequency to use. Otherwise you will be more likely to get interference and lose picture.
It can even cause overheat and damage to the video transmitter, because sending power into an unmatched antenna can reflect power back where it can build up as heat.
Anyway, for FPV most antennas designed for 5.8GHz should be fine for all the channels in A, B, E, F and R bands, unless it’s stated otherwise in the product specifications.
Stands for “Voltage Standing Wave Ratio”. It’s a measure of how efficient an antenna is – how much energy you put into the antenna and how much is bounced back.
When we are designing an antenna, we aim for a VSWR value as close to 1 as possible. At 1 VSWR, it means we can transfer 100% of the energy into the antenna, and out to the real world.
It’s considered reasonable to have a VSWR between 1 and 2, anything above 2 is poorly performing.
Note that VSWR changes with frequency. When talking about the tuning of an antenna, basically that’s the frequency with the lowest VSWR.
OwlRC makes a cheap VSWR (or SWR) meter for hobbyist use.
Types of Antennas
We have covered most of the basics in FPV antenna, and now I can finally introduce you some common types of antennas used for FPV.
|Linear Polarized||Monopole, Dipole||Patch|
|Circular Polarized||Cloverleaf, Skew-Planar Wheel, Pagoda||Helical, Patch, Crosshair|
Monopole antenna is the simplest form of antenna, which is basically just a piece of un-shielded wire. It’s very common in radio receivers because they are cheap and easy to repair. However they are not as effective as Dipole antennas. The length of the exposed wire is crucial as it determines the resonant frequency (frequency that it can pick up).
Tutorial: how to make Monopole antenna.
Nearly all video transmitters and receivers come with a dipole antenna. They are light weight, and can be made very durable against crashes.
Dipole antennas has a simple design. It’s basically just a monopole antenna with a ground sleeve at under the active element. The ground sleeve can supposedly boost the performance considerably.
Cloverleaf and Skew-Planar Wheel Antennas
The cloverleaf and skew-planar wheel have been the most common antennas for mini quad FPV. Cloverleaf has 3 lobes while skew-planar wheel has four lobes.
These antennas are omni-directional like dipole. But they are circularly polarized and provide better reception and yet also less susceptible to multi-pathing, so you can fly around walls and trees with better video quality.
They are however relatively fragile therefore often come in different cases and protection. They are sometimes called “mushroom antenna” because of the shape of the housing.
Pagoda is a relatively new antenna design in the FPV scene since 2016. It’s an omnidirectional circular polarized antenna. The unique design and use of material (PCB) makes it very durable. It’s relatively easy to make and so very popular among DIY’ers as well.
See our discussion on Pagoda antennas for more detail.
Helical antennas are spring-shaped, directional circular polarized antennas. The number of turns of coil determines the gain of the antenna. For more detail check out our article on Helical antenna and Patch antenna.
Patch antennas are also directional, and can be found in linear and circular polarization.
These antennas are less laborious to manufacture on a reliable way, as they are essentially just copper traces printed on circuit boards. However the dielectric constant of the circuit board means they are inherently less efficient compared to other types of antennas such as the helical.
They generally have less directionality than Helical, and smaller foot-print.
Considerations in Choosing Antenna for FPV
For beginners, it’s best to start with omni-directional circularly polarized antennas, for example the cloverleaf or pagoda.
Antenna performance relies heavily on decent material and precision, good antennas would therefore cost more. However some top notch antennas can cost 2 to 3 times more than the lower end ones, while they might only bring 5% or 10% range improvement.
Axial ratio is also an important factor to consider, which isn’t normally mentioned by manufacturer. But you might be able to find out their performance from reviews online.
After all, it all depends on what you can afford and your research on products.
Once you’ve invested in a diversity receiver setup, you can then look into getting some directional antennas to improve signal quality and range.
What Antennas For VTX and VRX
When buying FPV antennas in pair, normally they are interchangeable and can be used on either TX or RX. Otherwise, they should be clearly labelled “TX” and “RX” on the outside.
Antennas on VTX and VRX don’t have to be the same. Directional antennas are often used on VRX to get more range. While on the VTX you should always use omni-directional antennas, due to the fact that quadcopters can be in different orientation during flight.
Antenna Connector Types
For antenna connectors, we normally have SMA and RP-SMA. They are different in design and not compatible with each other, so make sure you buy the right one. Check this article to see the differences between SMA and RP-SMA. If you new to the hobby, try to stick with just SMA for your gear to avoid confusing yourself in the future. There is no difference in performance.
“U.FL” connectors are popular in VTX designed for racing due to the light weight and compact size for mini quad. But these are extremely fragile and have very limited mating cycles.
MMCX is a new type of connector that is being used in VTX and antennas. It’s a perfect balance between SMA and U.FL connectors in terms of weight and size. It’s much stronger than U.FL and have a lot more mating cycle. This is the my personal favorite at the moment.
A racing drone will inevitably experience many crashes during its life time. Since the antenna is installed on the outside of the frame, it will take no less abuse than the propellers and the frame. Therefore choose your antenna base on your likelihood of crashing. If you crash a lot, durability and robustness should be your priority in choosing FPV antenna.
One thing people usually overlook is the size and weight of the antenna. It’s becoming more important as mini quads are getting lighter and lighter. Every gram you save can improve the performance of your quad.
How to Mount VTX Antenna?
The best VTX antenna orientation depends on your flying style. Assuming you would be spending the majority of your flight cruising forward, your quadcopter might be tilted forward 30 to 45 degrees. Your antenna would work most effectively pointing vertically (due to its doughnut shape radiation pattern), which means it should be tilted backward 30 to 45 degrees when the quadcopter is lying flat on the table.
To get the best possible signal, the VTX antenna should stay in line of sight with the video receiver antennas at all time free of obstruction. One solution is to use a tall antenna so the frame, GoPro and LiPo battery can’t block the signal during flight.
However long antenna can create vibration during flight which will make your drone harder to tune or requires more noise filtering which compromises performance. So that’s one sacrifice you might have to make.
Racing drones have the VTX antenna mounted entirely inside TPU mount for durability. While this is not a problem for short range flying, you might want to avoid it for long range as having antenna active element mounted in TPU might detune its resonant frequency and degrade performance.
How to Mount Video Receiver Antenna?
If using a single receiver module, I recommend a circular polarised onmi-directional antenna. On a diversity set-ups (as most people would have), I recommend using a patch and a onmi-directional antenna for the best all around performance.
For long range, it’s a good idea to have your VRX on a ground station to prevent head movements, which might change VRX antenna orientation unexpectedly during flight. Having a spotter might be helpful as they can help adjust your patch antenna to make sure they are always pointing at your model. If you have the patch on your goggles, you can also try to move your head to point the patch at your model when signal gets weak.
Can I Use SMA Adapters?
You can get adapters to convert between different connectors (RP-SMA, SMA, MMCX, U.FL etc). These adapters can even come with 45 degrees or 90 degree angle if you want to point the antenna at certain angle.
There is some signal loss when using these adapters, or extension coax wires, usually a few percent of power loss depending on the quality and design.
But sometimes the benefits of using an adapter or extension out-weighs the little signal loss. For example, you can use an extension coax wire to increase the separation between VTX antenna and radio receiver, or other sources of interference. Or you can use a 45-degree adapter to optimize your video receiver antenna orientation.
Avoid adapters whenever you can, but when they are necessary, don’t be afraid to use them :)
DIY FPV Antenna
5.8GHz antennas for FPV are not hard to DIY, but to get it perform well requires high level of precision. I do recommend buying them because they are not that expensive, but if you are feeling adventurous feel free to give it a go :)
- My attempt at making cloverleaf antennas: https://oscarliang.com/make-diy-cloverleaf-antenna/
- Pagoda assembly video: https://www.youtube.com/watch?v=49rRR8iEiKc
- DIY Helical by IBCrazy: https://www.rcgroups.com/….Circularly-Polarized-Helical-antenna…
So that covers some of basics and considerations in choosing your 5.8GHz FPV antenna, and some antenna recommendations for FPV flying. I hope this guide has helped you to choose the best FPV antenna for your mini quad!
- May 2017 – Article Created
- Sep 2018 – Updated “Antenna Recommendations” and Added info about “Antenna Frequency”
- March 2019 – added info about VSWR, adapters and extension cables
- July 2020 – updated products
- Mar 2022 – updated products
- Jun 2022 – added detail about how to mount VTX/VRX antennas