In my very first project to receive satellite images, I built a V-dipole antenna. It’s very easy to make and produces convincing results.
The downside ? All those gray interference bands on every image.
I tried countless fixes to remove them but to no avail, so I decided to switch to a quadrifilar antenna, or QFH (QuadriFilar Helicoidal). Let’s see if this solves the problem :)

The QFH antenna consists of two helical loops, each wrapped around a central axis and offset by 90°. For more on phase shift, check out this lesson.
Thanks to this phase offset, the helices produce circular polarization. Think of it as the "direction" of the electric field in our wave.

Unlike the V-dipole we previously built that has horizontal polarization, which causes losses because satellite signals are circularly polarized, the QFH is designed to match the incoming circular polarization.

Keep in mind that your antenna will ultimately look like this (in 2D diagrams it might not seem that way):

To design the antenna, we’ll use this calculator.

After filling in the defaults, click Calculate.
You’ll get an approximate schematic. Note the -0.5cm on the top 4 wires only, this ensures there’s enough space between them to join together.

Let’s start by listing the supplies (excluding tools). For the copper, I used spare copper crowns from air conditioning work. It’s annealed copper, so it’s very malleable.

To simplify the build, I used a PVC sleeve that we will place on top of the antenna.
You’ll need to drill 4 holes perfectly perpendicular around the sleeve. For that, head back to this site and scroll down to Generate a drilling template.
Fill in the outer diameter of the sleeve (58mm) and the copper tube diameter (9.5mm).

Once generated, print the template and keep only the Top portion.
Wrap it around the PVC tube. It’s crucial that the paper exactly covers the tube’s circumference, an error of even 1mm can affect the alignment of the 4 copper rods. If it doesn’t fit perfectly, double-check your measurements.

Return to the Generate a drilling template section of the calculator. This time, use the outer diameter of the PVC tube (52mm), be sure not to confuse it with the sleeve’s diameter used for the top.

Then, cut out the Bottom part of the template to wrap around the tube.
To know where to place it, note the value 695.10mm on the template, this represents the distance from the top wires to point A (essentially, the H2 distance on the antenna diagram).

You can loosely position the elbows (without fixing them) at the end of each of the 4 long copper rods, either on the top or bottom of the antenna, the goal is to form a smooth curve. You might need to tighten the elbows slightly to prevent slippage while bending.
For bending, several techniques exist, in my case, I did it manually following this principle:

⚠️ IMPORTANT: The satellite signals we want to receive are Right-Hand Circularly Polarized (RHCP). This means you must bend the tubes in a counterclockwise direction when viewed from above. Once satisfied with the bending, fix the elbows permanently. I was fortunate to have access to a strong abrader, which was simpler and faster than soldering with tin.

Using water on the copper helps cool it to prevent the PVC from melting due to heat.
Alternatively, you can clamp the elbows tightly with the tube. The contact may not be perfect, but it works in a pinch.

Now, we’ll drill 2 holes at the top of the tube to create a balun.
The signal converts into current in one branch in one direction and in the other branch in the opposite direction, meaning the current is balanced in the antenna.
However, in a coaxial cable, the current travels only in the center, making it unbalanced. The outer braid is tied to ground and serves as a shield to prevent the cable from acting as an antenna (and to protect the signal).
If left uncorrected, some of the received signal will go to ground, causing significant losses.
A balun converts from balanced to unbalanced (or vice versa), resolving this issue.

This is a 1:1 balun. The first “1” represents the impedance on the balanced side (the antenna, approximately 50Ω), and the second “1” is for the unbalanced side (the cable, also 50Ω). In a 1:1 balun, these two impedances are equal.
The choice of 4 turns is not absolute but appears optimal for VHF waves.

There are several ways to connect the rods. Here’s a schematic of the proper wiring:

First, drill small holes at the end of each copper rod and file them smooth.

Then, wire the connections as shown in the diagram. I did it without soldering by twisting the wires together and securing them with zip ties.

Soldering is ideal, but for signals like NOAA and METEOR, this method works.

Here, the red illustrates the current from the cable's center and the blue from the braid. Finally, cover the top to protect the wiring from the rain.

I drilled a small hole at the bottom of the tube to let the cable exit, this prevents it from being crushed when laying the antenna flat.

To raise the antenna as high as possible, I added an extra piece of PVC tube. Lacking a sleeve to connect them, I used a T-joint. And there you have it, the antenna proudly installed on my roof.

Now, let’s check its performance using an antenna tester. Although these values are mostly useful for transmission, they help verify if our antenna is well tuned.

The VSWR is 1.487, which is excellent for a DIY QFH antenna, anything <1.5 means it’s well calibrated.
The impedance of 46.21Ω is also very good, as it’s close to the desired 50Ω.

Finally, here’s the output the antenna provides:

Concerning the original interference issue, my images now show (almost) no interference! Check out some examples in my gallery.