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low elevation for prodelin 2.4m offset

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Jan 23rd, 2008 at 5:48pm  
What is the low angle I can go for a 2.4 m prodelin( 22.3° elevation offset angle). I want to point to a satellite with 17 deg elevation. If installed upright I will have - 5 deg . Can the dish go that much forward? I know it can go 1 deg but 5 deg I don't know.
We want to avoid the bird bath approach to avoid the high BUC issue when dismantling in cyclonic gust. Any good advice is welcome. Should we increase the pole length to avoid the low BUC now?
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Reply #1 - Jan 23rd, 2008 at 5:59pm  
If you're installing in Mauritius, how did you arrive at a 17 degree angle of elevation? That would suggest you're attempting to point at a satellite on an eastern or western horizon. Which satellite?

//greg//
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Eric Johnston
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Reply #2 - Jan 23rd, 2008 at 11:34pm  
Your problem is how far back the bottom of the dish and the metalwork at the back end of the feed arm can go back towards the pole.

If your pole has any tripod type legs arrange for them not to be right where the bottom of the dish wants to go.

With the dish front upright measure the clearance behind the bottom rear.

Measure the distance from the elevation axis to the lower edge and multiply by 0.088 and that will be the approx distance that the bottom edge needs moving backwards, for a -5 deg tilt of the front.

Best regards, Eric.

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Reply #3 - Jan 24th, 2008 at 4:32pm  
Thank you for answer though not so clear. "'Measure the distance from the elevation axis to the lower edge""
cannot get the idea well . Pole length from pivot = 64". pivot point to pole = 4". pole to dish face/straight = 16"
yes we want to catch AB3 /5 deg W
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Eric Johnston
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Reply #4 - Jan 24th, 2008 at 5:12pm  
The elevation axis is the axial centre line through big horizontal bearing bolt which holds the dish backing structure to the bracket on top of the pole.   Just measure from there down to the lower edge of the dish.

Multiply the distance by 0.088 (which is tan 5 deg)

Starting with the dish front face vertical, that gives the approximate movement backwards of the bottom rear edge of the dish towards the pole.  Is there enough space ?

If you know exactly what model is the antenna you can look at the data sheet here antenna data sheets
Down to 5 deg is likely to be possible.

Best regards, Eric.
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Reply #5 - Jan 25th, 2008 at 5:14am  
The 1244 series have this in its spec - Elevation Adjustment Range 5° to 90° Continuous Fine Adjustment. I believe this is true elevation without the offset. Since I will be at 17 deg I think it is possible.
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« Last Edit: Jan 26th, 2008 at 2:00pm by Admin1 »  
 
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