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Some of the older SG-2100s from DMSI had U-bolts that would strip very easily if tightened even a bit too much. The metal was some sort of soft pot metal, and it was common to destroy a U-bolt. They have since improved on the U-bolt quality, but I do remember having to buy a replacement set of U-bolts when I installed my first motor.

Motor level

See my post of yesterday on this forum regarding U bolts.

Tron said:

Some of the older SG-2100s from DMSI had U-bolts that would strip very easily if tightened even a bit too much. The metal was some sort of soft pot metal, and it was common to destroy a U-bolt. They have since improved on the U-bolt quality, but I do remember having to buy a replacement set of U-bolts when I installed my first motor.

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Re U-bolts, my NEW DMSI version had U-bolts that were spread out so much that the ends were about 3/4" wider than at the middle. I had to bend them to get them to either go into the bracket or to be able to tighten the nuts on the other end, because it flared out so much that the didn't even touch the open end of the clamp part that the nut is supposed to tighten on. But the worst part was that right out of the box, the nuts couldn't be screwed onto the U-bolts, even 1/8th of a turn. The nuts wouldn't go on good bolts of the same size, and good nuts wouldn't go on the bolts. I couldn't find my tap/die of that size, so I ended up FORCING the nuts over the U-bolts, which was not easy at all, but after doing that 5 or 6 times, it finally loosened up enough that I could turn the nuts by hand. But at first, I couldn't even turn the nuts with a cresent wrench... had to use a deep 6 sided socket, and when I got past the depth it would go, I took off the ratchet, and turned the socket with a vice grip, letting the U-bolt go through the square hole. But basically, the U-bolts, nuts, and the whole mount assembly is a piece of junk.
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I just pulled up an OLD picture of my OLD SG2100. I wasn't sure where I had bought this, because the Sadoun sticker has long ago worn off, but I see now. Attaching 3 pictures below. The 2nd and 3rd show the Sadoun Digipower SG2100 sitting very flat on a pipe clamp I use to support the mount as I adjust azimuth. This OLD 2100 sits perfectly flat on any flat surface, and the various edges are all square. Also the top of the motor itself has a flat surface where the Digipower tag is, that can be used for adjusting elevation. The 1st picture is of my NEW DMSI 2100. It's hard to see in the picture, but the bracket doesn't sit flat on the same pipe clamp, or on any other flat surface. You can see space under the bracket, and it just rocks on a flat surface. It is of cheaper grade metal, and bends easily. Also I couldn't find ANY flat surface on the motor that could be used for elevation, although you can use the bent motor shaft once the motor is on the pole, and before you put the dish on. Also, these two motors have different designs relative to where the bolts attach to the motor, and to how the pointers point to the angle scale. I found the old scale fairly easy to use, once I figured out what part of the pointer to use, but this new 2100 has a pointer that is at least a degree off regardless of how you use it. I had a really hard time setting up this new 2100. I eventually used the back of the pole mount bracket of the 90CM Fortec, where it connects to the bent part of the motor shaft, as a surface parallel to the motor shaft, using the 90-decl-30 method described in another thread. That saved me from having to remove the dish to measure the angle.


Also, I'm not sure that one of the OP'er's comments was ever addressed. Above, it was mentioned:

rogerduncan100 said:

The SG2100's 30 degree bend is itself a compromise. I think the only way to get a motorized dish to follow the arc perfectly is to set it up with the exact right bend for the latitude.

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I just wanted to make sure that the OP'er realizes that this bend has nothing to do with the latitude. It is there to allow you to adjust for declination. Declination is a negative angle, but the dishes you attach to the motor shaft only allow you to tilt it at positive angles, so to get say a -5 degree declination, the bend in the shaft gives you a -30 declination, and then you adjust the DISH elevation to +25 to get a net -5. None of this involves latitude. This 30 deg bend also makes the axis of rotation go closer to the center of gravity of the dish, so that there is less torque on the motor. So it doesn't matter WHAT the bend in the motor shaft is, because it's accounted for by the dish elevation setting.

B.J. I agree with you after thinking about it for a few months. The amount of bend it the motor shaft doesn't affect how it follows the arc. You just make sure the axis of the motor is parallel to the Earth's axis.

I have given up my quest to change this from parallel to get a more perfect dish setup because the mathematics is difficult (parametric equations of cones).

I just finished manually calculating declination angles to south (79.3 degrees W), 30W and 125W and have found a difference of only 0.3 degrees. If I level my motor perfectly in the spring (when the weather is nice) all I have to do (theoretically) is aim 0.15 degrees high at south it will be only 0.15 degrees low at the extremes. That amount of imprecision is unfortunately necessary but probably doesn't make much practical difference.

PS: Despite what some say I still think I can use USALs to aim correctly. I will find out in the spring!

Got a magnetic protractor from HD (Home Depot) for $9.00, saved me some headace. If you want a good sturdy motor for FTA Get a Pansat PM900S They have all staneless steel gears, shafts and, bearrings. Problem is that it is about $120.00 From Pansat Direct, check many other places online as well and big side is that it has a 2 year warranty and it is made in Europe in Solovina. It is also setup for USALS.