How to size a parabolic antenna for 5.8ghz and 2.4ghz?

I’m building a parabolic antenna for my drone and need help calculating the dimensions. I want a 5.8GHz RX antenna and a 2.4GHz TX antenna, but I’m unsure about the size, focal point, and other specs. I have a 3D printer and decent 3D modeling skills, so I can fabricate the parts. Is there a calculator for this, or are there formulas I need to work out? Any advice would be appreciated.

It depends on your gimbal pointing accuracy. You want the beamwidth of the antenna to be a little larger than your pointing accuracy to ensure good performance.

Ari said:
It depends on your gimbal pointing accuracy. You want the beamwidth of the antenna to be a little larger than your pointing accuracy to ensure good performance.

I’m doing this by hand for now. A proper gimbal is outside my budget at the moment. What dimensions are determined by the frequency, and what can I adjust freely? I’m considering a single-axis curved reflector to simplify things.

@Vic
The frequency affects the size of the dish and focal point. A bigger dish gives more gain but narrows the beam. Higher frequencies require smaller dishes for the same gain. If you’re experimenting, try simple designs like soda-can reflectors. They’re easy to make and test.

You can use this calculator to start: Dipole Calculator | Antenna Length Calculator

Daire said:
You can use this calculator to start: Dipole Calculator | Antenna Length Calculator

That’s for a dipole, not a parabolic antenna, right?

Vic said:

Daire said:
You can use this calculator to start: Dipole Calculator | Antenna Length Calculator

That’s for a dipole, not a parabolic antenna, right?

Correct, but the dipole works as the central antenna, and the dish enhances its gain by focusing signals to it.

@Daire
I already have a 5.8GHz sleeve dipole. I just need the parabolic dimensions.

Vic said:
@Daire
I already have a 5.8GHz sleeve dipole. I just need the parabolic dimensions.

The dish should connect to the dipole’s ground to block interference from the sides and back.

@Daire
So I should ground the whole reflector to the dipole’s ground connection?

Vic said:
@Daire
So I should ground the whole reflector to the dipole’s ground connection?

Yes, that’s how it typically works. Also, make sure the reflector wires match the frequency wavelength for optimal performance.