Declination ?/Problem

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Long Hair

SatelliteGuys Pro
Original poster
Jun 17, 2009
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Mo
I was adjusting my declination and noticed that my elevation moved as well. Is this a problem:confused:
 
I was adjusting my declination and noticed that my elevation moved as well. Is this a problem:confused:

Changing declination will affect your ability to accurately traverse the arc. For peak performance you'll need to fine tune the dish.
 
Changing declination will affect your ability to accurately traverse the arc. For peak performance you'll need to fine tune the dish.

the reason I adjusted the declination was to fine tune, than I checked the elevation and it moved as well. So again I ask should my elevation move when setting the declination? My elevation should be 39.60, after setting my declination 5 degrees. My elevation moved to 41, it should stay at 39.60 right?
 
The two interact.
So, get solidly on a satellite,
Then you measure and change the declination a little,
That screws up your elevation, so you adjust only the elevation to bring you back onto the bird.
Then, you can run the arc again to see how well you track.


This is only one component of a comprehensive retracking, but it answers the question asked.
For a fuller discussion, I'd refer you to the GeoOrbit site.
Near the bottom of that page is a graphic which should help you understand what to do, depending on your tracking error.

Here on the site is more info on declination.
The chart at the bottom of this page is the only one I'd ever use:
Modified Polar Mount Tracking Angles

edit:
In a perfect world, you measure and set your declination ONCE, and leave it alone!
Only if you see a tracking error as described above, might you consider changing it.
 
Is this on a BUD?
If so, changing the Declination angle should not change the Main Axis Elevation, you should only see a change on the Face of the Dish.
 
Is this on a BUD?
If so, changing the Declination angle should not change the Main Axis Elevation, you should only see a change on the Face of the Dish.

Lak this is a 7.5 unimesh bud. And that is what I thought,I think if my elevation is changing than the bolt for the elevation might be lose where it bolts up the the mount causing it to slip just a bit. At one time about a week ago I think I had my declination set close because I was able to pick up ku band, but now only c band.
I'm sure my declination is off because on sat w5 on hbo 4dtv h= 89quality and v=58 quality. It makes no real difference if I adjust my skew. I'll post a pic showing what I think my problem is.
 

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That is the same mount I have.
Make sure everything is tight. Check the 2 Nuts with the Cotter Pins. :)
Get everything tight, then set the Main Axis to your proper setting. I found no "prefect" place to measure Declination on that mount.
I found the most important thing is the Azimuth, use every trick in the book to get the Azimuth correct.
I set the Azimuth to the actual Main Axis Square Tube, then set the Main Axis Elevation.
 
I found no "prefect" place to measure Declination on that mount.


yeah I noticed that, I measure declination from the front center plate. Unless someone thinks this is a bad idea?
 
I have the same mout and it drove me crazy trying to track the belt . I was trying to set the declination from the same point ( the plate) but after several attemps still couldn't quite get it. What i did was use a straight edge ( 1/2" x 2" aluminum bar ) and put it rite on the rim of the dish ( on the face ) and there it was , i am now able to track the entire belt.
 
I don't mean to hijack here, but I notice in that picture of the unimesh that the declination adjustment is at the bottom of the dish mount.

Does it make any difference if it's at the top or bottom? Mine's at the top and that's how it was when got it. If that can cause issues, I want that taken care of before things get cold.
 
the reason I adjusted the declination was to fine tune, than I checked the elevation and it moved as well. So again I ask should my elevation move when setting the declination? My elevation should be 39.60, after setting my declination 5 degrees. My elevation moved to 41, it should stay at 39.60 right?

Yes, elevation and declination interact so your elevation will change with declination adjustments.
 
Is this on a BUD?
If so, changing the Declination angle should not change the Main Axis Elevation, you should only see a change on the Face of the Dish.

You're right. But, changing the declination will change the view of the satellite arc. Effectively changing the elevation.
 
I don't mean to hijack here, but I notice in that picture of the unimesh that the declination adjustment is at the bottom of the dish mount.

Does it make any difference if it's at the top or bottom? Mine's at the top and that's how it was when got it. If that can cause issues, I want that taken care of before things get cold.

Yes, it does make a difference. Mines at the top but I use calibrated shims to adjust declination instead of adjustable rods. I don't think my declination is correct either but I doubt I'll get that determined/resolved before this weekends cold front.
 
So, the declination adjustment is supposed to tilt the dish up and back from below, rather than lower the elevation from the top.

Interesting....

My declination adjustment moves the reflector down and forward.
 
I was just saying that if the declination adjustment is at the bottom of the dish and was fully extended your dish would be higher in elevation, as opposed to having the declination adjustment at the top where it would lower the dish elevation if it was fully extended.
 
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