Yet another Usals question

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Blindowl1234

SatelliteGuys Pro
Original poster
Dec 16, 2008
2,035
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SouthWest Ohio
Ok guys I'm experimenting with Usals on an Openbox. In the two years I've been into FTA I've never bothered with Usals. I put my Lat as 39.21 and Long as 84.14 and have the dish and SG2100 on 85W..closest to true south. It doesn't seem to track properly. I might get 87W or 85W but I can't get anything above that. I've tried playing with the latitude setting and adjusting it a little one way or the other...still no improvement. It always tracks fine using 1.2 but not Usals. Over the years I've read where everyone likes Usals because its easier? What am I doing wrong? I'm missing something simple for sure...Thanks Blind:)
 
Ok guys I'm experimenting with Usals on an Openbox. In the two years I've been into FTA I've never bothered with Usals. I put my Lat as 39.21 and Long as 84.14 and have the dish and SG2100 on 85W..closest to true south. It doesn't seem to track properly. I might get 87W or 85W but I can't get anything above that. I've tried playing with the latitude setting and adjusting it a little one way or the other...still no improvement. It always tracks fine using 1.2 but not Usals. Over the years I've read where everyone likes Usals because its easier? What am I doing wrong? I'm missing something simple for sure...Thanks Blind:)

BlindOwl,

Please be patient with me if some of the stuff I say here is redundant for you. I apologize for that, but I must get myself in gear to explain certain things. Bare with me, ok?

Obviously, I bring out the dead horse to beat on it again... Is your mast perfectly plumb and is it sturdy? Be very critical of this, don't fudge!

If your latitude is 39.21°N and your longitude is 84.14°W, use those coordinates for your USALS entries. I don't know how far the Openbox fields go out past the decimal point but most receivers allow only one decimal position so you should probably enter 39.2°N and 84.1°W.

If you can manage it with the dish installed, slap an inclinometer on the belly of the motor (you must be on the flat surface of the motor's underbelly). Read the angle. This should be 50.79° (90° - 39.21°). Set your motor latitude adjustment so that the incliometer reads 50.79° elevation. Well. as close to 50.8° as you can get.

Command the motor to go to reference or go to zero. Set your dish elevation according to the manual's instructions or determine the elevation angle with an on-line calculator. I say go to zero or the home poition so that your motor tube is straight. This makes adjusting the dish elevation better because gravity is pulling straight down on the dish assembly so there is little chance of your dish mounting bracket twisting on you while the bolts are loosened. That can introduce an unwanted error to your alignment that is hard to detect, but really throws you off the arc. Tighten the bolts up (just not overtight), don't be the gorilla.

Very important thing to check at this point, is your dish bracket centered on your motor tube? The vertical axis of your dish pan must be perfectly in line with the vertical axis of the motor tube when the motor is at zero degrees. Just a smidgeon of error here will throw your arc off. Same as with a twist in your dish mounting bracket assembly.

Go into your menus and set up satellite AMC 16 to be at 85.0°W and select USALS. In your manual or TP menu, select this sat and TP 12183 MHz 3978 symbol rate, Horizontal. Your TP frequency might be a little off from mine, but you will know it as the Echostar Satellite Access Ctr TP.

Now drive the motor with your receiver to AMC 16 and monitor your signal quality while you grasp the dish pan and give it a gentle pull up, down, to the right and to the left. Can you improve the signal quality? If you can, adjust the motor azimuth on the pole or the dish elevation to peak the signal as best you can.

Now, using USALS, how far can you go and still pick up a sat properly? What is the furthest sat east and west that you can make it to before the signal starts to degrade on you?

Stop there and grasp your dish and try to improve the signal. Which way do you have to move it to make the most improvement. If it is east or west, adjust your motor azimuth on the mast but DO NOT move anything else. If it is up and down, adjust your dish elevation, but DO NOT adjust the azimuth. Now go to the other side of the arc to the furthest sat that you can still get a signal from and adjust the other angle (if you adjusted azimuth before, now adjust the dish elevation or vice versa). Go back and forth from one side of the arc to the other and adjust either your dish elevation or your motor azimuth but remember to adjust only one thing on each side and stick with that method through the entire procedure.

If your dish bracket is a bit flimsy, drive it back to ZERO before making the elevation adjustment otherwise the bracket may flex on you and introduce a new error and you will really be fighting ghosts and phantoms!

This is the calibration procedure and you must do it for both DiSEqC 1.2 and USALS if you want your dish and motor to be set right. It is just a lot easier with USALS because some of the work is being done for you by the USALS calculations.

I honestly swear to you that once you get accustomed to this practice, you will look back and have a V-8 moment (if you remember those commercials). If you get it down pat this way, you will be setting up dishes on the fly in 15 minutes! And, they will be on the arc!

RADAR
 
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I should add that my brother has recently purchased an OpenBox and he is LOVING it! He is controlling a 1.2 M Ku-band offset dish / motor with it and using USALS, too. Therefore, if you need specific information regarding the receiver and USALS, we can go to him for first hand experience.

RADAR
 
Radar, Thanks for the info. This setup has been using Disecq 1.2 for over 18 months with no problem tracking from 61W to 125W. Signal is excellent across the arc. When I set it up for Usals it will usually get a strong tp on 85w...and then Patient channel on 87W is good and a very weak signal on RTN at 83W. Nothing else above or below that. I think I tried this two years ago with my old Fortec Dynamic and got the same results. Seems simple enough to enter the numbers and it should work but I've never had any luck with it. I can see the setup outside the window to the Tv room and when its set for Usals it is moving the dish a little past the place where it would go if I were using Disecq 1.2. Thats what I can't figure out. I've played with the Longitude and Latitude settings to see if I can get it to not overshoot the next satellite.. doesn't work that way either lol..
The dish and motor are perfectly aligned though. Using Diseqc commands it moves east to 63W SCETV at 60 % and west to 125W with all the PBS at 70% except for LPB which is typically a little lower it seems. Gets everything in between fine too...I'm stumped....I just thought I try Usals after all this time to see how it worked. Thanks Blind
 
if USALS does NOT point your dish at the selected satellite that means your motor is not aimed 100% correctly, you could be off slightly on the AZ, or the motor elevation, or the dish elevation, or your MOTOR may not be 100% level....or a combination of any of these....

do not ASSUME that your MOTOR is level just because your pole is....after you snug your motor bolts down you should use a small level to check and see if your MOTOR BRACKET is level in all directions....that is whats important, not the pole....

the pole could move slightly while your aiming and tightening the bolts, although a properly installed pole should not....i have also seen motor brackets get twisted from overtightening the bolts....so bottom line is its always best to check the motor bracket to see if its level after installation is complete....
 
Just because DiSEqC positioning tracks the arc well doesn't mean the motor is correctly aligned. Radar's technique or other alignment approaches should be used with USALS commanding to tune the alignment before taking any other steps.

Nevertheless your system may be perfectly aligned with USALS and still not work very well. There could be a variety of problems internal to the motor that would masquerade in this manner. For example, if the motor's zero angle position is significantly offset, you will have a devil of a time trying to compensate with alignment alone. Both of my USALS motors exhibit some aspect of this problem. One does severely (several degrees) while the other is workable.

Since I wrote my own positioning software, I compensated for this with a calibration constant and was able to get both motors tracking as well as can be done with USALS. However no matter how well one aligns a USALS motor, there are some well understood limitations to its accuracy that cannot be easily dealt with.

USALS assumes a zero polar axis tilt, and thus cannot accurately track the extremes of the arc without introducing an appropriate polar axis tilt and either modifying the positioning software or fibbing about the orbital locations. This has been a hot topic on Rick's recently, and I brought this up in a "USALS Notebook" thread here if you want more details. The bottom line is there are a number of circumstances where DiSEqC is a better choice. I don't use USALS anymore.
 
Mikey & Pendragon,. Well i recently changed the SG2100 motor too. Didn't touch the bracket at all. The old motor had way too much play in it. The motor was put in the exact same position using sharpie pen. It's dead on where it should be using Diseqc. Well until it warms up outside(only 45 today) I'm not going to mess with it. I'm going to look and see how much farther the motor moves past its target sat when it moves. Looking out the window yesterday it looked to overshoot the desired sat with Usals by a good 4-6 inches. That was on 101W. Diseqc works for me and has all this time so unless I get a bold streak maybe I'll leave it alone for now lol. Guess if it ain't broke leave it alone...Blind
 
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