Anyone install a Orbitron 8.5 with Spinclination?

[daverfw]

I aquired a Orbitron 8.5 foot dish, and have it mounted, but am having issues peaking the signal, and one thing I have found hard to get info on is this Spinclination the dish uses, has anyone else here setup one of these? and If i am falling off the arc what should I adjust, this has a H-H motor also. thanks!

[wejones]

Originally Posted by daverfw

I aquired a Orbitron 8.5 foot dish, and have it mounted, but am having issues peaking the signal, and one thing I have found hard to get info on is this Spinclination the dish uses, has anyone else here setup one of these? and If i am falling off the arc what should I adjust, this has a H-H motor also. thanks!

Yep, I have a 10' spinclination. Does your dish have markings on the hub area where the dish can "spin"??? If so, that is how you change the declination. If you don't have markings, which was the case with my dish, then you'll have to make a scale, which I can help with if that's the case.
Basically, with the dish rotated to it's lowest position, like 6-oclock, that would correspond to a declination of -8 degrees. With the dish rotated up, to 12 oclock, that corresponds to a declination of +8 (you'll never need a + declination obviously). Rotated to 3 or 9 oclock is zero declination. Between 6 and either 3 or 9 oclock are the declination angles between zero and 8. This is VERY accurate for setting declination. You should set this, and then never touch it again. This really should be set before you even set up your feedhorn, because rotating the dish changes the polarity.
Also important, is that if you rotate the dish say to 7 oclock, which would be 2*8/3 =5.33degrees, you'd get the exact same declination if you rotate the dish to 5 oclock, however there is a difference, because rotating it to 7 oclock aims the dish more to the west, meaning that you may not be able to get to the horizon in the east, whereas rotating to 5 oclock aims the dish a bit to the east, meaning that you may not be able to reach the horizon to the west. So choose the way you rotate it based on what sats you need to see near the horizon.

[grndcomm]

I had the 12' Orbitron with splination, most likely the same procedure for yours. It was put up in 1989, so I don't really remember how I set it up, except there was an index mark and I think I rotated the dish until my latitude lined up with the index mark. What kind of markings are on the hub where you turn the dish?

Grndcomm

[daverfw]

mine still has the marking tape, barely readable but i can , i moved it to 32 degrees for my latitude, only thing is, when i tighten the 3 bolts to set it, it pushes the dish out, and i am affraid that changes the angle a little of the dish

[wejones]

Originally Posted by daverfw

mine still has the marking tape, barely readable but i can , i moved it to 32 degrees for my latitude, only thing is, when i tighten the 3 bolts to set it, it pushes the dish out, and i am affraid that changes the angle a little of the dish

I didn't have that problem, but I don't think it will matter. As long as it pushes the dish hub tight against the mount cylinder it fits into, it should be OK. There shouldn't be enough free play of that pipe inside a pipe hub to make much of an angle, but if there is a lot of free space, maybe slip some shims in there to keep it from moving while you are tightening the bolts.
Sounds like the previous owner over tightened it, and bent the inside tube or something. You can always check that you have the right angle by putting an inclinometer on the flat plate at the back of the dish. Inclinometers are only accurate to a half degree or so, but that's all you really need. At least it will tell you if you are in the ballpark. The inclinometers usually can read either inclination or 90-inclination depending on which surface you use. If you use one surface on the round plate on the dish, and the other surface on the outside of the mount hub right next to it, the difference should be the declination. (Another way of saying that is that those two surfaces are nearly (except for the declination) at right angles to each other.

[daverfw]

where can i find what that elevation should read? i have a inclinometer, and have tried putting it against the plate, i am in zip code 76116, thanks!

[rainman]

I've got the same dish still got the paper work with it let me check tonight if i can find it and will let you know.

[wejones]

Originally Posted by daverfw

where can i find what that elevation should read? i have a inclinometer, and have tried putting it against the plate, i am in zip code 76116, thanks!

There are many places to find the angles. I would recommend setting your main rotation axis (ie the BIG bolt that tilts the whole motor assembly) so that the inclination on the outside of that hub tube is about 56.7 degrees when at it's highest position, aiming south. You should use a declination that is about 4.7 degrees, which means that the dish should actually look 4.7 degrees lower than this, ie 52.0 degrees. However that flat plate is perpindicular to the dish aim, so you might see 90 minus that angle on your inclinometer, or 38 degrees.
However, what is important for tracking is really the DIFFERENCE in these two numbers, ie if you measure 56.7 and 52, subtract the two, and you should get your 4.7 degree declination. The absolute numbers will be adjusted accurately by peaking on a satellite, but you need to get this difference close by using the spinclination and/or the difference in the inclinometer readings.

[daverfw]

well I had a local satellite comapny come out and align it, $85 later and its setup great

[rainman]

Originally Posted by daverfw

well I had a local satellite comapny come out and align it, $85 later and its setup great

great glad to here you got it up and running now enjoy surffing the sats.