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Originally Posted by wejones
"But one of the members here recently found that his LNBF support arm was bent, placing it nearly up where a prime focus feed would be. It almost sounds to me like your lnbf arm might be bent too.
If you place a straight-edge across the front of the dish from top to bottom, then place a big carpenter's square on this straight-edge so that it aligns with the lnbf..... where on the dish does the lnbf hit? Ie close to the bottom edge, or near the center of the dish??? I'm almost guessing that yours is bent up, so the lnbf is closer to the center of the dish, when looking perpindicular to the straight edge across the dish."
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wejones you are right. I realize the focal distance does not measure from the center of the dish for an offset type. It can be measured if one knows the offset angle (24.62 in my case) and some elipse calculations. The fact I measured from center and the 120 cm dish size explains the 645 mm number instead of 600 mm Due to arm and supporting bars shortness the LNB is pulled up towards the center of the dish, not quite in the center but close. I hope with the right arm and supporting bars to be able to bring the LNB into the focal point. I only hope I did not deformed the dish too much (it does not look to deformed). Thank you.