right angles? channelmaster, sg-2100

[MichaelH]

I need some help with setting up the declination? (dish bracket) angle with my current setup. I'm mounting a channelmaster dish onto a motech sg-2100 motor. I had to flip the dish bracket to work with the motor so the bracket angles are upside down.
heres the angle settings I'm working with;

Motor Latitude: 32.8
Declination: 5.3
Dish Elevation: 25
Azimuth (magnetic): 175.8

Problem is it looks like I can't angle the dish up any further so I'm thinking of detaching the motor tube, flipping it 180 degrees and reattaching it so that it angles the dish upwards. If I do this I will have to compensate by angling the dish bracket down some. I may need to buy an angle finder but I would prefer avoiding that if I could. What am I calculating the dish bracket angle relative to? The horizon, the dish, or perpendicular to the ground? Is it ok to remount the motor tube 180 degrees? Anyone else tried this setup have any tips?

 

[Lak7]

How heavy is the Dish?
An SG2100 is only rated for about 25 Pound Dish.

Motor is set to You Latitude, make sure you are using the Motor's Latitude Scale and not the Elevation Scale. Then, make sure you are using the correct indicator on the Motor, it is not the Bolt on the SG2100, see Pic below.

Are you sure you need to flip the Bracket?
The angles provided by a "Dish Pointing" site have the Declination built in already.
Motor: You Lat on the Lat Scale
Dish: 25 degrees or best signal
Pole must be Plumb in both directions.

 

[B.J.]

If it IS necessary to flip the mount, it may well be possible to get the proper angles by flipping the shaft by 180 degrees, however that will put the center of gravity of the dish considerably further away from the rotation axis, which will increase the torque on the motor. So if the motor is at all marginal for that dish, flipping the shaft may mean the motor will not be able to handle it.
If the reason you need to flip the mount upside down is because the pipe can only go in from one direction, I think I would consider getting some generic mount, and adapting it. If it's due to where the holes are on the shaft, I think I'd drill new holes.

 

[MichaelH]

Hey Lak,

Thanks for the informative reply. Yes the motor is set at latitude 32.8 measured with the triangle not the bolt. Sorry for the confusion in the illustration (it's changed). I measure the dish and the bracket at 12lbs. With the invacom lnb it shouldn't exceed 15lbs.

I do need to flip the bracket to be able to fit to the motor tube. The motor tube came without holes drilled (courtesy the geniuses who made them), so I had to drill my own thinking I needed to flip the bracket. But being the genius that I am, I didn't think I might as well drill holes higher up the tube so I didn't need to flip the bracket which I just realized upon typing this reply.

Another would be to flip the motor so the tube is oriented upwards but that would mean I'd have to readjust the motor latitude/elevation. The best option I'm considering is to either reattach the tube 180 degrees or drill holes higher up the tube to be able to orient the dish bracket to it's default position.

 

[Mr Tony]

Lak
Those Channelmaster dishes like that are mainly used for Starchoice installations. They are actually really light as the mounting bracket is flush with the dish, not like the Primestar doshes where it was a much bigger bracket

 

[Lak7]

If you drill your own holes, be absolutely sure they are Square to the Motor.
Otherwise you will have a very difficult time, or unable to, track the Arc.

 

[MichaelH]

Ok, so I tried to install the motor tube in the opposite side of the dish bracket and saw that it will not work since the tube is blocked by the bracket. Then I realized I actually did consider this before when I first started this project about 2 months or so ago.

So there are a few options left. 1) I rotate the motor tube 180 degrees but It may orient the dish at too much of an acute angle upwards. 2) I remount the engine upside down so that the tube is facing upwards therefore allowing a default orientation for the dish bracket. 3) I buy a generic dish bracket and retro that to the dish ( a lot more work). 4) I buy a new dish and my problem is solved (least amount of work).

What do you guys think?

Thanks a bunch for all your help on this.

 

[mjac]

What do you guys think?

I realize its not the same dish but this worked for me.
I the interest of giving credit where credit due, this is a "Stogie" design that I "borrowed" as I am sure several others did.

 

[MichaelH]

Thanks for that image mjac. If I do decide to fit another bracket onto my dish I'll consider that layout.

So I tried rotating the tube 180 to allow for more upward angles of the dish. In that respect I succeeded. My only concern is that offset center of gravity will tax the motor too much even though the dish with bracket and lnb will be 10lbs under the limit. Now how do I figure the right angle on the dish bracket? With the motor tube rotated 180, do I need to change the motor latitude/elevation? I think it's safe to say I need an angle finder at this point. Thanks all for your help.

 

[Larobpra]

That setup looks to me like it would just skew the dish rather than track the arc properly. But then I haven't tried anything like that.

 

[Lak7]

Can you try:
Return Tube to proper position, and on the Bracket, use the other Hole to mount to the Tube.

 

[MichaelH]

That won't work Lak. The hole is only on one side and I won't be able to use the degree notches to measure against.

 

[MichaelH]

Well I have the dish setup and rotating. The drawback with my current configuration is that I can only rotate the dish 40degrees in either direction from 0 position without stalling when rotating back. To solve this I thought of flipping the motor but then west will rotate east and visaversa and I don't think any receiver software I've read of will take that into account.

I had questions about whether it would track the arc with tube reversed so I set out to simulate it on a 3d graphics software. I set up two dishes; one with the tube at default and the angles set to my settings, the other in the rotated position and angles adjusted to take into account the new tube orientation and animated them to rotate 80 degrees from left to right. They both draw a similar arc so we could rule that question out. My computer crashed before I can't render out some images from the program but I'll see what I can do about getting another test out.

 

[Anole]

holy grail of motor mounts:

See the post and pictures by 7720driver: http://www.satelliteguys.us/free-air-fta-discussion/23072-primestar-dish-sg2100-4.html#post493584
He inverted the tube and made it work.

Go back to the first page of that thread, to see how ZipLoc fabricated his own bracketry from off-the-shelf parts.
DirtyShame came up with a simplified design around page three, that morphed into 7720's design.

 

[MichaelH]

Thank you for those links Anole. They'll come in handy if I ever need to fabricate a new mount for a dish in the future. Right now I have my dish mounted and have a good angle range as far as declination goes. My only problems now are finding the right angles and getting my motor not to stall on the way back from greater than 40degrees from true south on either direction. I have an idea how I might be able to do that using rubber cords to counterbalance the torque.

 

[MichaelH]

Ok, so I got a bit a problem getting any kind of quality signal. My true south satellite appears to be Galaxy25 at 97w. I'm using my receiver as well as a generic signal finder to find the strongest signal. I was able to find a strong signal with my signal finder but my receiver never seems to register any signal above 19percent. My diseqc switch is DMI and so is my sg2100. A few things I found interesting though. Sometimes I'll get a stronger signal when my signal finder is connected. Today I tried bypassing the the diseqc switch and motor and my signal went up to 40percent. I wonder if my diseqc switch is bad. Anyone else get a problem receiving a signal with a Channelmaster 75e oval dish and Invacom LNB motorized setup? Thanks for all your suggestions!

 

[MichaelH]

I have Signal! . After troubleshooting the connections and settings I was able to get an 80% signal and 90% quality. The DMI diseqc switch I was using seems to be faulty since once I bypassed it and connected the lnb directly to the motor I was able to get a strong signal. Plus I had the wrong lnb selected in the receiver settings for the satellite. I've got one more diseqc switch so I'm going to try that and see if that one works. Now to see if I can track the arc and receive the other satellites viewable to me.

 

[phlatwound]

Well done, congrats!

 

[MichaelH]

Thank you Phlatwound! I'll bet some pics up as soon as I get it set up the way I want it.