Thread: So I'm reading the manual for the SG2100...

And the manual tells you to look up the elevation / declination settings depending on your latitude. No problem so far...

It then tells you to set the elevation angle of the motor - no doubt from that table you just looked at. - No problem...

It then tells you to find you declination angle on the table and it's a small number - like 8°. It then says "Set the declination angle by the scale on the antenna dish. The reading on the dish scale should be 40° declination angle".

Why did They have me look up the declination angle if I'm just going to set it to 40°?

Maybe this will make more sense when I have this stuff in hand - lol.

You are right you will not really need the declination angle, just use the motor and dish angles from the Angle Table. Set the motor elevation and never touch it again. Then set the dish elevation, but this angle can be changed slightly (up or down) to peak your signal quality when on a satellite.

Originally Posted by Shawn95GT

It then tells you to find you declination angle on the table and it's a small number - like 8°. It then says "Set the declination angle by the scale on the antenna dish. The reading on the dish scale should be 40° declination angle".

Why did They have me look up the declination angle if I'm just going to set it to 40°?

What my book says is "The reading on the dish scale should be 30° - (MINUS) declination angle" "Please refer to the drawing on Page 3"

30° minus 8° = 22° the approximate setting on the dish scale.

Hope that clarifies it for you.

"The reading on the dish scale should be 40° declination angle."

Go back and reread it again. I believe it says "40 - declination angle". So, if your declination angle is 8, then you set the angle of the dish to about 32 or somewhere thereabout. Of course you may need to tweak this later.

EDit:
What DaveC says may be correct. I've seen conflicting information regarding the SG2100. I've seen some places that say "40 - declination" and others that say "30 - declination". I don't know whether this is an error or perhaps there were 2 different models of the same motor.

From what I've read there were maybe two different arms used on the sg2100, one arm used a 30 angle and one used a 40 angle. I have the book that came with my sg2100 and it shows a 30 degree angle to the motor arm, been several years since I set mine up now.

The pole is of course vertical, the motor mounts to that there is an angle adjustment to the motor at the bracket. Then there is an additional angle adjustment between the motor arm and the actual dish. my dish has no angle indicator I had to peak it manually and get it aligned correctly on the arc.

Originally Posted by Stefan

"The reading on the dish scale should be 40° declination angle."

Go back and reread it again. I believe it says "40 - declination angle". So, if your declination angle is 8, then you set the angle of the dish to about 32 or somewhere thereabout. Of course you may need to tweak this later.

Yup - you got it, it does have the "-" in there.

I think SG2100 quickly got adopted as a name for a motor by different brands. I think this is why the different 30° / 40° arms.

That P990 or whatever it is seems to be the same as a SG2100 with a smaller swing radius... like 90° vs 140°.

How are you planning to attach your primestar dish to the SG2100? I used the original mount turned upside down. I used 2 pieces of PVC pipe to go between the motor shaft and the primestar mount and adapt it to fit. I used a piece of 1.5" schedule 40 PVC pipe and a piece of 2.0" schedule 40 PVC pipe. It is necessary to cut a slit down the length of both pieces of pipe. The slit in the 1.5" pipe allows it to expand to fit tightly to the SG2100 shaft as the inside of the 1.5" pipe is slightly too smal to fit over it without the slit cut into it. The slit in the 2.0" pipe allows it to compress enough to fit into the Primestar mount. When you cut the slit in the 2" pipe you must make it wide enough to allow for the pipe to compress enough to fit. If I recall correctly I cut mine about 3/8" to 1/2" wide.

One other thing I had to do was trim some material off the mount with a dremel. If you look at the primestar mount where bolts tighten up and clamp the mount to the pole, you'll notice there is kind of a ridge or lip on one side that will butt up against the other side when the bolts are tightened to a certain point. This was probably done to limit the amount the mount could clamp down on the pole such that overtightening the bolts wouldn't result in compressing in the sides of the pole and distorting it's cross section into an oval. In order to make it work in this configuration and be able to compress the PVC pipe around the SG2100 shaft this ridge must be removed or partially removed to allow the bolts to be tightened farther and generate more clamping force. So that's what I did. The result is a pretty nice mount that's not to difficult to construct and allows for easy adjustment of declination by simply turning the adjustment bolt on the bottom (which was on top in the original configuration). Anyway, if you have the original mount, a couple of pieces of PVC pipe and a dremel handy, this might be something you want to look at trying.

I built my own lighter mount, pics and drawings here: http://www.satelliteguys.us/showthread.php?t=42450

I might give either of those a shot.

I had originally saw your instructions Ziploc but then I thought it might be cool to have skew adjustment... so I pretty much bolted the P* dish to a Dish500. It is yet to be seen if this ghetto attachment will work out but if I cna make the original P* mount work it'd most definately be stronger.

I've got a good week before I even get my reciever so I'll take the P* mount apart and look it over. I thought the whole problem with the P* mount was the sheer weight of it. The original elevation adjustment is kind of cool and I wouldn't mind retaining it.