Construction of the 8.5M dish

For the making of the ribs a jig was build on the garage wall. On the wall the shape was made using wood, slightly thinner than the aluminium. This jig was used to cut all the aluminium pieces used for the rib.

All these pieces could be put in the jig and screwed together with stainless steel self tapping screws and aluminium mounting plates.

After one side was screwed together the rib was taken out of the jig and turned around.

Note (on the wall) that also for the aluminium mounting plates drilling jigs were made. Allowing “mass” production of these plates

PA3DWW, Dre, welding together the hub. The hub was made out of iron tubing about 18cm thick and is about 60cm high. On the iron tube 8 nuts are welded. Bolts fitted in these nuts will later fit the dish on the mount.

Loosening these bolts will allow to rotate the dish around its centre, thus allowing to work on the mesh / ribs when mounted in place.

Fitting of the ribs to the hub. Dre is drilling holes in the rib. The ribs are mounted using U-bar stainless steel and stainless steel bolts and washers. Any other material will corrode with the aluminium.

Mounting the concentric rings, these rings will keep the ribs in place and has to be done carefully. The hub rotates on the mount as described above. A fixed reference point assures that the ribs are mounted all the same.

The mesh is first cut in triangles, 2 triangles coming out of a rectangular piece of mesh. Avoiding waste. What size mesh can you get? Think of this when planning the number of ribs.

Especially the mounting of the mesh near the hub was a difficult task. Mesh mounting was done using small pieces of zinc plated wire and a pair of pliers.

On the photo PA3CSG “crawling” under the dish. PA3DWW doing the “top” work.

Mounting the bearings on the elevation system.

The dish going into place using a relatively light crane to put it on the tower.

Putting the dish in its place and mounting of the elevation system. For the elevation an actuator from a army personnel carrier is used.

Note Hubert, ON6JZ standing on a small platform. The platform can be folded down when not in use. The allows easy working on the elevation system.

The dish mounted on the tower. No feed installed yet. The steel tubing for the counterweights is mounted. The counterweights are still not on.

Standing under the tower is PA3CJN (RIP). In the background a “pile” of aluminium, being my old 16 yagi array.

The dish is ready. Note that the feed is not at all connected to the dish itself. The feed is very heavy and more than 4 meters in front of the dish. Mounting the dish feed directly to the ribs of the dish will almost certain cause the dish to deform. This system allows to lower the feed to the ground so that I can easily access it.