Mtuko2,
As given in attached photo, ensure the diameters of the fully assembled dish measures between 71 and 71.5 inches. If the diameters are not equal, the prime focal point will be misplaced and you could lose 10 to 20% in signal quality for fringe satellite reception (e.g. Nilesats). You may use steel wire to tighten the diameters A-D, B-E and C-F as per the suggested measurements. Once these three wires (diameters) meet / touch at the middle, then the original focal point of the dish will be aligned.
For the Eurostar 180Cm dish, the ratio of diameter and focal length (distance between the LNB position and the bottom of the dish) is given as:
F/D ratio = 0.38;
where: F is focal length; D is the diameter.
Therefore, since D = 180Cm, then F = 68.4Cm
Also, if dish is badly dented, first dismantle it and straighten the six petal-like plates with a light hammer. In addition, ensure the three LNB holder arms are straight. These three arms meet at the focal point. Therefore, the distance from the center of the LNB holder to the bottom of the dish should be approximately 68.4Cm.
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