36-inch motorized dish question

[johnny33156]

A couple of months ago I programmed a 36-inch dish with a SG-2100 H-H motor. I live in Miami Fl. ( 80 degrees today ) I set the motor elevation to 25.5 and the dish elevation to 26 and I found more then 10 satellites.
Now I am using a new SG-2100 motor and a different kind of 36-inch dish.
I can only find signal quality on the same ten satellites if I set the dish elevation to 34. Also my quality #s seem a little lower. I don't know if that's because this is a cheaper dish ($39.00) or if I'm just not completely in the arc.
Is the dish elevation always need to the same as the motor or does it depend on the dish.
Thanks in advance for any help with this question.

Johnny

 

[schlever]

It sounds like the dish just needs to be tweaked more in order to get it on the arc. The elevation numbers on the dish mount, especially on cheaper dishes, are more of a reference than anything.

Go to your true south satellite and slowly adjust the dish to tweak it to the highest possible signal there by adjusting the elevation and you should be good. Also make sure that the lnb has no skew (i.e. set to zero) as the motor will take care of the skew for you.

Since it is a new motor as well, have you ensured that the pole is perfectly plumb, and the motor has been adjusted to the proper elevation for TS?

 

[Anole]

another little secret

While all of the above is true, there is one other little thing to check.
Some motors have their shaft bent at different angles than others.
And the 10 degrees error you report sounds about right.
Not saying that is the problem, but I would double check the paperwork with both motors...
There were some production changes to one distributor's line of "2100's" as well as clone 2100's from others...

edit: reference material

 

[brentb636]

AND to go back to the dish bracket marking issue, we've seen some very inaccurate bracket markings for dish elevation. My 90cm FortecStar bracket is quite accurate, but the 80cm FortecStar dish bracket is off by about 7 degrees. Once you figure out that tweaking that dish elevation adjustment is part of the tuning, you'll be happy with the results.
All the suggested angles, etc are just to get you into the ballpark. The motor itself is pretty precise, but the rest of the hardware is real low precision build. Once you get "quality" on your receiver, you then work to optimize it.


Brent

 

[johnny33156]

Thanks for all the information reguarding my post.
I will peak again my nearest South satellite and see if I can't get a little
more quality. Thanks also for the info on the motor and elevation settings for some dishes.

 

[greyskies]

Similar location and Situation

I am near Fort Lauderdale, with similar elevation, longitude and latitude. So the motor and dish angles are quite similar. The TS bird for johnny33156 and me is AMC 5 (79.0W).

I have adjusted my 3.5 year old Motek SG2100 and tinkered with the dish elevation angle, as well as the azimuth settings for my setup. Get signal and decent quality (from 123, 121, 119, 110, 105, 103, 101, 97, 93, 91, 89, 87, 83, 82, 79, 74 and 61.5).

My signal with USALS is dead on with Nimiq1 @ 91W. When I move west, my best signal is east of the USALS location (using DISEqC 1.2 to tweak), and conversely, when I move east, my best signal is west of the USALS location. The further east and west I move along the ARC, the more I have to tweak with 1.2 east (for western satellites) or west (for eastern satellites).

My mast is dead plumb. Never got it this sweet before.

This seems to be a situation where my tracking angle is less than that the actual parabola to accurately track the ARC.

Do I need to adjust the dish elevation angle (bigger number or lesser number - i.e. - I am current set at 27 or 28 while manual suggests I be at 26, but weaker signal at 26)?

Do I need to adjust the motor latitude angle from 26 higher or lower?

Please help me get this set for USALS so that I can also play with MythTV which requires USALS in order to use a motor.

 

[stogie5150]

Sounds like you have a bit of slack somewhere in the rig. I use homebrew mounts for my P* 1m dishes, and they have a bit of slack in them so I have to bump them about a bit. But I use a standalone box to move my dishes so that's no problem.

Without seeing your setup, and with you saying the motor is 3.5 years old, I would say you have a bit of slack in there.

Keep at it and let us know how you do!

 

[greyskies]

Slack? - Please elaborate on what you mean.

"stogie5150 Sounds like you have a bit of slack somewhere in the rig. I use homebrew mounts for my P* 1m dishes, and they have a bit of slack in them so I have to bump them about a bit. But I use a standalone box to move my dishes so that's no problem.

Without seeing your setup, and with you saying the motor is 3.5 years old, I would say you have a bit of slack in there.

Keep at it and let us know how you do!"

I am term challenged ( I use words for a living, I am a lawyer). Please elaborate on what you mean by "slack".

Where do you suggest I look and attempt changes?

Could "slack" exist in the motor's shaft? It is rusted solid and there is a slight amount of "play" (which i define as looseness. By that I mean that when it is locked on zero (0) and not connected to anything, it can be toggled/moved the slightest bit. Not along its scales, but ever so slightly jiggled.

If this is the type of slack that you are referring to, any suggestions on how to take this into account and accomodate for it? Better yet, since it is rusted solid, any suggestions on how I can remove it? I have a 50cm shaft sitting in my closet that I never used and could replace the original shaft.

Thanks for your assistance

PS - I am going to see if my wife will let me use her digital camera. No reason to doubt it, but hey, its her camera. If so, when I get some time, I will take pictures of my setup as that might help you or others determine my problem(s).

 

[jerryt]

I am near Fort Lauderdale, with similar elevation, longitude and latitude. So the motor and dish angles are quite similar. The TS bird for johnny33156 and me is AMC 5 (79.0W).

I have adjusted my 3.5 year old Motek SG2100 and tinkered with the dish elevation angle, as well as the azimuth settings for my setup. Get signal and decent quality (from 123, 121, 119, 110, 105, 103, 101, 97, 93, 91, 89, 87, 83, 82, 79, 74 and 61.5).

My signal with USALS is dead on with Nimiq1 @ 91W. When I move west, my best signal is east of the USALS location (using DISEqC 1.2 to tweak), and conversely, when I move east, my best signal is west of the USALS location. The further east and west I move along the ARC, the more I have to tweak with 1.2 east (for western satellites) or west (for eastern satellites).

My mast is dead plumb. Never got it this sweet before.

This seems to be a situation where my tracking angle is less than that the actual parabola to accurately track the ARC.

Do I need to adjust the dish elevation angle (bigger number or lesser number - i.e. - I am current set at 27 or 28 while manual suggests I be at 26, but weaker signal at 26)?

Do I need to adjust the motor latitude angle from 26 higher or lower?

Please help me get this set for USALS so that I can also play with MythTV which requires USALS in order to use a motor.

Follow this guide.

 

[stogie5150]

stogie5150 Sounds like you have a bit of slack somewhere in the rig. I use homebrew mounts for my P* 1m dishes, and they have a bit of slack in them so I have to bump them about a bit. But I use a standalone box to move my dishes so that's no problem.

Without seeing your setup, and with you saying the motor is 3.5 years old, I would say you have a bit of slack in there.

Keep at it and let us know how you do!

I am term challenged ( I use words for a living, I am a lawyer). Please elaborate on what you mean by "slack".

Where do you suggest I look and attempt changes?

Could "slack" exist in the motor's shaft? It is rusted solid and there is a slight amount of "play" (which i define as looseness. By that I mean that when it is locked on zero (0) and not connected to anything, it can be toggled/moved the slightest bit. Not along its scales, but ever so slightly jiggled.

If this is the type of slack that you are referring to, any suggestions on how to take this into account and accomodate for it? Better yet, since it is rusted solid, any suggestions on how I can remove it? I have a 50cm shaft sitting in my closet that I never used and could replace the original shaft.

Thanks for your assistance

PS - I am going to see if my wife will let me use her digital camera. No reason to doubt it, but hey, its her camera. If so, when I get some time, I will take pictures of my setup as that might help you or others determine my problem(s).

That's exactly what I mean. There is a little play in ALL motors. Some have adjustment to take that out, some don't. Let me dig around a bit here somewhere...I think its on DMS website how to do it...

ah! here it is...this is ONLY if you have a Sg2100 motor By the way, and I've never done it so do it at your own risk....

http://www.dmsiusa.com/documents/Backlash Adjustment.pdf

 

[greyskies]

That's exactly what I mean. There is a little play in ALL motors. Some have adjustment to take that out, some don't. Let me dig around a bit here somewhere...I think its on DMS website how to do it...

ah! here it is...this is ONLY if you have a Sg2100 motor By the way, and I've never done it so do it at your own risk....

http://www.dmsiusa.com/documents/Backlash Adjustment.pdf

Thanks for the PDF file. Read the Backlash Adjustment, but do not understand what that is for, except perhaps when a motor does not go to zero (0) when sending it back to reference point. My motor, goes to zero, no issue there. What I was explaining is that there is the ever so slightest wobble, maybe that is a more explicit explanation of what I was referencing. Could a part inside the motor warped over the past 3.5 years, resulting in that little bit of play?

Will pass on hammering the screws on the motor for now. Btw, yes, I do have a Motek SG2100 motor, so if I understand backlash adjustment, those instructions would help me with my motor.

Let me ask 1 other question. There are two sides for the bracket that holds the motor to the mast. Each side has markings. The setting for my latitude is 26.0 degrees North. Should that be the same setting on both sides of the motor bracket, or should each side be different? Wondering if that is impacting my tracking of the ARC?

Any thoughts on these questions?

 

[Tron]

You should use the latitude side, and set the motor at the latitude of your location, as close as you can approximate it to the markings on the scale.

 

[stogie5150]

Thanks for the PDF file. Read the Backlash Adjustment, but do not understand what that is for, except perhaps when a motor does not go to zero (0) when sending it back to reference point. My motor, goes to zero, no issue there. What I was explaining is that there is the ever so slightest wobble, maybe that is a more explicit explanation of what I was referencing. Could a part inside the motor warped over the past 3.5 years, resulting in that little bit of play?

Will pass on hammering the screws on the motor for now. Btw, yes, I do have a Motek SG2100 motor, so if I understand backlash adjustment, those instructions would help me with my motor.

Let me ask 1 other question. There are two sides for the bracket that holds the motor to the mast. Each side has markings. The setting for my latitude is 26.0 degrees North. Should that be the same setting on both sides of the motor bracket, or should each side be different? Wondering if that is impacting my tracking of the ARC?

Any thoughts on these questions?

Backlash adjustment fixes EXACTLY what you describe, the side to side 'wobble' in the motor shaft itself. The 'zero' is a different thing entirely....you should have a hole right next to the green light on the motor, you can reset/rezero the motor by sticking a paperclip in there and gently pushing the reset button.

Backlash is a bigger problem I would think on the larger dish/motor combos where there is considerable strain on the shaft...I am not wild about hammering on my motor either BUT if I suspected that backlash was the problem I'd get myself a meter and go at it.

In your case I would eliminate everything else before I did that though. What I would do is take the whole thing down, reset the motor, reset the receiver, and start over like it was a new, out of the box install. Like Tron said above, use the latitude side, disregard the elevation side.

Let us know how you do. :up