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Originally Posted by rainman
if the dish is warped could cause problem. easy way to check for warpage is to string it in two points where string cross center of dish at 90 degrees string should barely touch each other. if not touching or pressing tightly against each other dish is warped.also you want to check the sat arm. :mozilla_smile:
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I agree that a warped dish could cause a problem, but I'm not sure that I agree with the string technique, unless you're talking about a prime focus dish, which we're not. The string thing seems to come close, but I think it's mainly because most of these offset dishes are very shallow dishes, ie nearly flat anyway, so there is very little curve in either direction, so the string will come close to crossing at the same point, and if there is warpage, you will see a difference.
I may be wrong, or missing something, but I don't think that in theory that the strings should necessarily cross exactly at the same point, unless you choose the position of the strings to be +/- 45 deg relative to a vertical line through the dish, and in this case it wouldn't be able to detect warpage along that verticle line, although it would be able to detect twist around that line. I "THINK" that the crossing point of the strings depends on the overall shape of the dish, ie how wide the dish is relative to the height, and on what orientation you place the strings. I think the string thing can be helpful if done right, but don't expect them to cross exactly at the same point in general. I think that if the dish is warped enough to kill your reception completely, you'd be able to see the warpage without the strings anyway.
However, back to the original problem, while a couple of my dishes ARE warped, one of them to the extent that it basically doesn't work, it's not that the signal just goes to zero, but that the signal is spread out over a wide area instead of being focused into a narrow area. But with a signal meter, you should still see some signal, and you should see the signal change as you move the dish, even if the dish is warped. If one can't get a signal on one of the strong DBS sats with a circular LNBF, then I think that there must be something else wrong.
I'd get ahold of a voltmeter, and insure that you are getting DC voltage to the LNBF. I'd also double check the receiver settings. As has been discussed a lot, the Ultra receiver has a habit of changing settings when the number of transponders gets too large. Also, the hand held
signal meters seem to sometimes stop working in cold winter weather, and they typically don't work at all unless they are out at the dish. I'd connect direct from the Ultra to the LNB, bypassing the motor, and make sure that you have voltage at the LNBF, and connect the hand held meter, and adjust the little knob on it until you get a low pitch squeal. If you can't get a squeal at all, then you must not have any voltage, because those meters give a squeal even if pointed at the ground. Then, once you have the squeal, move the dish around by hand, and see if the pitch of the squeal changes.
If there have been high winds, I don't think it's very likely that the winds would warp the dish, it's very likely that the winds may have rotated the whole mount on the pole, so I'd first just start moving the south alignment of the mount, then if that doesn't give you a reading try the elevation adjustment as a last resort. Problem is, when you lose signal, there is a tendency to start moving things around on your aim, and once you start changing things, you are really back to square one on your alignment, particularly if you choose the wrong adjustment first.
Anyway, if you really have ZERO signal, then I think there is probably no voltage getting to the LNBF, but other than that, I really think that it's most likely just that the wind changed the aim, not warped the dish.
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