Quote:
Originally Posted by bill190
Was this the first time you were going to that particular satellite?
I read in the directions that this positioner has a feature called "Autofocus". And that it will go back and forth before storing the position of the satellite.
Seems to me USUALS is a "computer program" which calculates the position of all the other satellites based on the position of one known satellite. But where the satellite is and where the best signal may be received for that satellite may be slightly different.
So I think what this would do is "know" where a satellite is located, but test to be sure it is finding the best signal for that satellite? Or perhaps there is conflicting information with stored satellites and for some reason it can't rely on the USUALS software?
If this were true, then this would happen the FIRST time you went to each satellite, then the SECOND time you went to that same satellite, the positioner would go directly there????
Is this what is happening?
I don't know how "smart" these things are, but I know the capability is there to talk back and forth between the receiver and positioner. What about the situation where someone entered the wrong location for where the dish was located. Say they were in Florida and told the receiver/positioner they were located in Iowa. In theory the receiver/positioner could know it was not finding satellites where they should be, then set out to find the satellite on its own - searching the entire arc.
Just throwing out wild guesses here.... I know sometimes when they design things like this, they try to design them to work in many different situations. Like what if someone enters the wrong location? What should the positioner do? Or what if the location entered is slightly off from the actual location? What should the positioner do?
|
These things are not that smart. I don't know what this autofocus thing is, but my guess is that the most it can be is if you have found a satellite and are getting signal, that there might be a capability to go back and forth a bit to peak the signal. But it certainly cannot know that you aren't finding satellites in the right place or anything like that, because neither the motor nor the receiver really knows what sat you're even looking for.
USALS is a computer program in the receiver, not the motor. USALS calculates the rotation angle of the motor shaft vs the motor's zero position (not vs some known satellite, although in practice you locate the zero position by finding a known satellite) that corresponds to a difference in longitude between the user and the satellite. Ie if the sat you are looking for is at a longitude 30 degrees west of your due south, the USALS calculator might calculate that it requires a 33.4 degree rotation to aim at that sat. USALS has no idea of what sat you're looking for either, only that it is a certain angle east or west of you.
These receivers and motors don't know what sats are where, and certainly don't try to get so smart as to find a satellite on their own. They are supposed to do only what they are told to do. This behavior sounds really strange to me. I can't think of any good reason for it to do this. The suggestion the Corey gave makes as much sense as anything, but I really think that this should NEVER happen, because sometimes people install motors where they will physically bump into some obstruction in one direction, which is why they have LIMITS. If a motor was programmed to just ignore limits and go all the way to the physical limit, that could result in damage. I would really HOPE that these things were programmed to calibrate on ZERO, not on the physical east/west limits.
I could see a situation where the motor was trying to get to a satellite, and due to some error encountered what it thought was a physical limit, then decided to recalibrate by going back to it's zero, and then tried again, again encountering an error, back to zero, until it does it right. Ie I can see it going back and forth between one limit and zero, but not between 2 limits. Like Corey says, maybe if the motor loses power, it might have to find itself ONCE, but not multiple times. Perhaps there is an intermittant connection in the coax, so that the motor is occasionally losing power, forgetting where it was, so it keeps going through the recalibration thing until it manages to get there without losing power??? I just re-read the original message, and it just says that it does the full arc, but doesn't specify whether that full arc is from H-H or perhaps from zero to horizon.
But in any event, I really don't think that a properly working motor should do this, or at least it shouldn't do it more than once. I'd say that there is either a problem with the motor, or perhaps with the coax between the motor and receiver.
Linear Mode
