Zi Hao's Blog: Construction of the geodesic parabolic dish developed by JA6XKQ and 1.42Ghz cantenna

For the introduction of the design, please read this article [1] written by JA6XKQ. For those who are interested in the details of the derivation and surface accuracy of the structure, you can refer to [2]. Another important thing is the supporting structures such as adding supporting rods behind the dish or additional inner meshes to prevent the heavy feed from deforming the structure. See [3] and [4]. Please refer to the excel sheet from JA6XKQ's website at [5] to obtain the specific dimensions.

This is a 1.4m f/D 0.345 dish. Three L shape aluminium bar as supporting structure is attached to a stainless steel bowl. The same material is used for the feed supports and the reflector is made from galvanized wire mesh. This picture is taken months ago and the mesh is now covered with rust, I plan to apply rust converter to the surface and spray paint at the end. An alternative is to use stainless steel mesh at the beginning, but the cost will be high.

Cantenna's diameter: 14.5cm, length: 18cm, probe's distance from the back (1/3 of the length): 6cm, probe's length: I started with 0.25*λ, and it is trimmed until a good SWR is obtained with a NanoVNA. These dimensions are based off from the design from Figure 3 at [6]. If you want to determine the diameter based on your desired edge taper, you can see page 3 at [7]. To compute the dimensions of the cantenna and a choke ring, refer to the excel sheet from SETI League at [8].