OK1DFC 8m offset DISH ribs

September 2021

The shipment of material for the outer ring of the dish finally arrived today. It is a 5mm thick and 100 mm wide aluminum strip. I managed to complete the outer circuit and install a few more ribs. The last 13 ribs remain to be installed and the dish area will be complete.
The next day the work continued much faster. Half of the total number of extension ribs is installed.
The work was successful and I was able to start installing the extension ribs during the weekend.
I made 36 pieces of extension ribs in one week. Only every two ribs are identical and so the most time was spent rebuilding the welding jig. The right picture shows the longest rib at position 0 - 360 and the shortest rib at position 180

August 2021

The central part of the 4m diameter dish is completed. The mesh is attached to the outer wall of the dish and the whole is ready to be installed on the balancing boom. In the next few days I will be making 36 extension arms.
Ribs of the parabolic dish installed on the central hub
The first 5 pieces of ribs are made. It seems that the chosen replacement technology by welding the arms is leading to the goal.
The welded arm is mechanically very strong and retains its geometry after removal from the jig. The second picture shows the first arm installed at the centre of the dish.
The details of the arm welds, welding aluminum is not much fun, but a little practice is enough
First arm ready for welding Details of the positioning of the arm elements in the welding jig
Details of the positioning of the arm elements in the welding jig
For the production of ribs, a welding jig is required, which must be flexibly adjustable to produce different arm lengths.

April 2021

October 2020

 

I have divided the design of the dish into two separate parts. The so-called inner and outer dish. The inner part, with a diameter of 4m, is a separate parabola with eighteen massive supporting ribs. The outer parabola is made up of thirty-six circumferential ribs, which screw to the inner parabola. Unfortunately, the second wave of COVID19 stopped the production of external ribs, slowing the completion of the parabolic mirror. Also, the autumn weather doesn't want much outdoor work anymore. After many years of drought, we have a very rainy autumn. So I have at least modified the design feed for 1296 MHz and I use the 2.6m offset dish for this band as well. I hope to continue building a new dish soon.

 

22/09/2020

Longest parabola rib at 0

27/08/2020

3D model showing perfect shape of parabolic mirror. Right picture is look in to the dish with zero elevation, means -18,6 from zero