Question About SG-2100 Declination Angle Settings

[avenger]

Just came back from vacation, and have been following threads from the forums.

Decided to tackle my dish not tracking the satellites arc problem. Downloaded the "DiSeqc 1.2 Motorized H-H Motor" manual and read it from cover to cover.

According to the "Elevation and declination angle table" on page 6, my site Latitude which is 30 degrees and elevation angle of 60 degrees and declination angle of 4.961. Now on page 2 of the same manual it states " Set the Declination Angle by the scale on the antenna dish. The reading on the Dish scale should be: 40 degrees DECLINATION ANGLE", what is this statement saying.

Now, the Motor Elevation is always been set to 60 degrees, and Latitude to 30 degrees.

The Dish side "A" is set to about 25 degrees scale mark, which makes the "B" side to fall at the 60 degrees scale mark.

Besides moving/turning the dish East and West, what other adjustment are required to track the satellites arc. My home satellite is 89W Galaxy 28, and the quality signal is 75% for the test pattern channel and 73% for the two BYU channel,( that is all that scanned in) but at times the picture freezes.

As always any advice or comments are very well welcomed.

 

[SatelliteAV]

As usual, the instructions are written incorrectly. The correct dish elevation setting is "30" minus declination.

Make sure the post is perfectly plumb. Make sure the motor is also plumb to the mast and the bracket is not distorted.

Use USALS to drive the motor to 89w then rotate to motor on the mast and adjust the dish elevation to optimize Signal Quality.

Use USALS TO DRive to the East satellite limit and repeat with small adjustments to the motor position on mast and the dish elevation setting. Repeat on the west limit satellite. Check center, East and West to be sure all are optimized.

 

[Cham]

Make sure you enter the proper latitude and longitude in the USALS sub menu. I often put in the wrong coordinates when I am too lazy to go out and aim the dish properly after a windstorm etc, really messes things up after when actually aiming the dish with wrong coordinates!

 

[AcWxRadar]

Avenger,

I am not meaning to sound so much like I am just parroting Brian above, but I did want to add a few personal points to watch out for and a couple explanations/tricks.

The main items to be sure you set correctly are the latitude on the motor, the elevation of the dish and the plumb of the pole. Now what Brian mentioned about the motor bracket also being plumb, and SQUARE is important. The SG-2100 motor brackets aren't very thick or rigid so they can easily be deformed. Be cautious of how tight you run the nuts down on the clamping U-bolts or you can permanently deform the bracket and that will throw your arc tracking out the window (or at least limit the accuracy quite a bit).

The latitude angle on the motor should be equal to your site's actual latitude degree (30°).
If you are in doubt about the accuracy of the reading on the motor bracket, you can use a dial inclinometer placed on the FLAT bottom or belly of the motor.
The angle reading you get here will be the ELEVATION angle of the motor. Subtract this ELEVATION angle from 90° and the difference will be the latitude angle.

The dish elevation angle (when attached to a motor) has to take into account the bend in the motor tube. The SG-2100 motors have a 30° bend, so you subtract
the declination angle (4.961°) from 30° and you have your elevation angle.

There are a few other items you should watch out for. Ensure that the dish mount, where it attaches to the motor tube, is perfectly centered with the vertical axis of the tube and not off a little to the right or the left. Also, on the dish elevation adjustment bracket, ensure that when you secure the fasteners that the side plates of the adjustment bracket remain parallel. Best if you can set this adjustment with the dish off the motor and laying face down on the floor. This way there are no forces of the weight of the dish trying to pull on and twist the bracket while it is loose.

Enter your geographic coordinates (lat and long) in the motor USALS setup menus and drive the motor to your selected sat. Then, theoretically, all you should have to do is pan the motor bracket on the mast east to west / west to east in a field of about +/- 15° and you should detect your signal.

Best if you can set your TV/Receiver out at the dish so you can monitor the signal quality from one of the stronger TPs on the SAT as you make your adjustments. Having this immediate feedback is very
important to expedite the job and keep you sane.

RADAR