Make a DIY Cloverleaf Antenna

Cloverleaf antenna is a circular polarized antenna for FPV which is way better than the cheap dipole antenna that comes with video transmitters and receivers. Antenna is one of the most important parts of FPV system. In this tutorial I will show you how to DIY one.

Omni circular polarized antenna like Cloverleaf is one of the best FPV video transmitter antennas available to hobbyists. I explained the benefits of a circular polarized antenna over a linear one if you are not sure what are the differences.

What is a Cloverleaf Antenna

The Cloverleaf is a closed loop antenna which the signal and ground wires are connected. The cloverleaf antenna has 3 loops at 120 degree apart, and they are titled at 45 degree to horizontal plane.

cloverleaf-antenna-angle-diagram

Good and bad things about Cloverleaf Antenna

Circular polarized antennas are great for FPV video streams because they’re good at rejecting phase shifted signals (distorted signal) such as multipath interference. The cloverleaf antenna has an excellent radiation pattern and very low gain.

It is not the ideal receiver antenna however, because the reverse polarization rejection pattern is very erratic. You need to choose other types of antennas for the receiver such as the skew planar wheel (4 lobes).

Let’s get started!

Parts you will need

  • 0.8mm copper clad welding wire, it’s stiff and easy to solder (some people used 0.6mm also worked fine)
  • RG316 coax cable (or RG405)
  • Soldering tool

cl1

build-cloverleaf-antenna

Measuring and Cutting the antenna wires

The size of the antenna (the length of the wires) does not follow the rule of “bigger, better”. The length of antenna wires affects what signal frequency you can receive. The length you need for your desired frequency can be calculated using mathematical equations. Generally the length of wires would be smaller for higher frequency signals.

To make it easier for our readers, you can use this tool to calculate the required length of the wires:

Enter the frequency (for example 5.8 GHz = 5800 Mhz)
MHz (type, don’t paste)
Cut wires to:
mm

 

(Formula: Length in millimeter = 307022 / Frequency in MHz)

Use this tool to calculate where to bend the wires.

Enter the frequency  (for example 5.8 GHz = 5800 Mhz)
MHz (type, don’t paste)
Bend wires at:
mm

 

(Formula: Length in mm = 76755 / Frequency in MHz)

As an example, for the most common 5.8 GHz FPV system (5800 Mhz), the length of the wires should be 52.93mm, and it should be bend at 13.2mm. This is what the shape and measurements should look like.

cloverleaf-antenna-wire-measurement

Measure and cut 3 pieces of wires at the calculated length, cut them just a little bit longer (marked as optional above, so you have the extra length to solder to the main wire. Trim both ends so they are flat.

I bend the small piece of wire into square U shapes, and I personally don’t really leave the “optional” part in the wire.

cloverleaf-antenna2

cloverleaf-antenna3

cloverleaf-antenna4

The 3D design diagram with angles

cloverleaf-antenna-angle-diagram3

cloverleaf-antenna-angle-diagram2

Soldering

Cut your coax cable open, so the ground and signal wires are separated, exposed and ready to be soldered.

You don’t have to follow the picture below, you could cut your fingers :)

build-cloverleaf-antenna2

build-cloverleaf-antenna3

I put the bent copper wires on some blu-tac, and arrange them according to the 3D diagram above. For example for the VTX antenna, I put them about 120 degree apart, and for the VRX antenna, that should be approximately 90 degree.

cloverleaf-antenna5

And tilt the wires to the right 45 degree. This will make the antenna “right handed” polarized, since this is a more common configuration.

cloverleaf-antenna7

And finally solder all the tips together to the signal wire.
cloverleaf-antenna-wire-soldering7

Other Polarized Antenna Design

Skew Planar Wheel Antenna (4 lopes)

medium

Virevent Antenna (4 lopes)

Virevent-antenna

Windmill Antenna (5 lopes)

windmill-antenna

Conclusion

The key to making a successful FPV antenna is to be precise with measurement. The more accurate you can make the antenna the better it will perform.

21 thoughts on “Make a DIY Cloverleaf Antenna

  1. Zohaib Amir

    is that –> ‘307022’ supposed to be the speed of light? where did you get this value?
    If you wanna get an almost perfect value, you need to multiply the speed of light in vacuum (299792458 m/s) by the refractive index of air (1.000293)
    which is 299880297.19

    Calculating wire length (wavelength) using this value gives around 1mm difference in your values

    Reply
  2. Zohaib

    Something confuses me,
    the total length should be 1 Wavelength,
    the bend should be at 1/4 Wavelength,
    you calculate the Wavelength using speed of light 307022000, which equals to 52.93482758620689mm
    whereas Speed of light in Air according to Google is
    299700000
    so far i have found these values
    300000000
    307022000
    299792458
    299700000

    which one is Accurate?

    Reply
  3. Everton

    Well, this went way better than I expected. I used a common a 2.4ghz antenna, like those you have on your internet router. Just removed the cap from it an used the base (connector + 0º/45º/90º tilt angle). Honest, because it’s my first time doing this, it came out ugly, but the result was pretty good. Didn’t try it in the field yet, but inside my house the signal is amazing, even better than my others antennas. Looks like I’ll never buy antennas in my life again :D

    Reply
  4. Mark Lawson

    Great article, thank you. I would like to add that I use the brass rods available at many model shops easier to use and solder than the mig welding wire you are using. I bought a roll of the welding wire but in comparison to the brass rod found it very difficult to solder to, and the joints were far from reliable.

    Reply
  5. luke

    Sorry I got lost here:
    “For example for the VTX antenna, I put them about 120 degree apart, and for the VRX antenna, that should be approximately 90 degree”

    How can we create a full circle with 3 leaves 90deg apart?

    Appreciate if you can clarify.

    Thanks

    Reply
  6. Paul

    Hello, which antenna do you think is better for a 2.4GHz quadcopter(toy)? Many ppl uses a 5dbi 2.4GHz wifi antenna + a windsurfer

    I already made a quadrifilar helicoidal antenna 2.4GHz, testet it with my wifi and works fine, but Im just a noob and don’t know nothing about antennas, would be great if an expert can help me

    Reply
  7. Frank V.

    Hi Oscar,
    I couldn’t get the calculator to work, Looking at 2.4 Ghz and 5.4 Ghz. Please send values, or the equation (equation would be better!!! ;) ). Thanks!

    Frank

    Reply
  8. Wes

    Hi Oscar

    Great post. Do u know what material could be used to make the base rg316 bendable so it can be bent into a specific shape?

    Reply
    1. Oscar Post author

      Hi Serkan
      I think you are supposed to use wires that have good conductivity, copper is better than steel.
      also I prefer thicker wires, because they are tough so you don’t bend them by mistake during usage, or destroy them in a crash.

      Reply
      1. Serkan

        I want to use the SS wire because I couldn’t find MIG wire in my local shops :) I tried it yesterday but it is really hard to solder it. So I decided to try a brass wire. Electrolizing the SS wire ends with copper sulphate is another choice to me. Also IBCrazy said in one article galvanized wires are best if you we can find it.
        Do you mean pure copper while saying “copper”? Thick wires are said to have more interfenece wtih other frequencies. So they say to use as thin as possible. There is a confusion in the internet from this point of view. Some say thicker is better, and some say thicker wires causes interferences and gets the signals which they shouldn’t do. I am really confused and still searching…

  9. AuLeeFor

    What feed line lenght do you use for 5.8 Ghz tx -and rx-antenna? I got some knowledge about antenna theory and if I’m not mistaken feedline impedance is of great importance. How come that all tutorials about building fpv antennas never mention any thing about feedline lenghts? From what I understand it has to be odd multiples of quarter wavelength, including the velocity factor of the cable. I would really epreciate if anyone could clarify on that issue.

    Reply
    1. Ben

      Hi Oscar and AuLeeFor

      Great question about feedline impedance… I wish i had the answer for you :P
      I’ve noticed that the same thing, no guides refer to feedline length at all. And i’m less than impressed with the performance of any of the CL antenna’s i have tried. I guessing that there is a large impedance mismatch going on with the common designs that have been shared around… and i noticed that Ibcrazy’s new bluebeam antenna’s include a balun on the feedline.

      Looks like i’m gunna have to brush up on my maths and maybe look into getting myself a LCR meter to figure this one out ;)

      I’f you have come up with some answers in your search i’d love to hear it.

      Reply
  10. adiena

    nice article, but can u plis tell me where can i read this antenna’s formula for calculate the value of this antenna’s gain? and formula for calculate bend and length of wire without tool for calculated it at above?

    Reply

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