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Godfather
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Discussion Starter · #1 ·
My roofs peak line is at about 250 azimuth. The roof is 36 feet wide. The 5LNB dish sits at the right rear corner of the house. There is a tree line which runs almost parallel to the peak up the right side of the house. I've got a leaf problem with the 119 satellite, which is at azimuth 247 from my home in Estern PA. I had a DTV tech and supervisor in today. I wanted them to move the dish to a front corner, in effect moving the dish 30 feet towards the south (250 - 90). My reasoning was that the satellites are 26000 or so miles away and that there would be no parallax correction required for a 30 ft move. The dish would be clear of the trees and 119 would be good again. The guys said no, that if they moved the dish "left" 30 feet it would have to be repointed to the right and that 119 would would still be fouled by trees.

I said OK. There are 2 trees that are too close to the house that should be removed and this will fix the problem. On top of that I only get HDNET and ESPN2HD from that satellite and I can live without the DeuceHD until football season, but I'm curious. Are these guys right? Seems to me like its a trig problem where the angular change will be arctan 30ft/26000mi and thats a pretty small angle. What am I missing here?
 

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Hall Of Fame
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oldengineer said:
My roofs peak line is at about 250 azimuth. The roof is 36 feet wide. The 5LNB dish sits at the right rear corner of the house. There is a tree line which runs almost parallel to the peak up the right side of the house. I've got a leaf problem with the 119 satellite, which is at azimuth 247 from my home in Estern PA. I had a DTV tech and supervisor in today. I wanted them to move the dish to a front corner, in effect moving the dish 30 feet towards the south (250 - 90). My reasoning was that the satellites are 26000 or so miles away and that there would be no parallax correction required for a 30 ft move. The dish would be clear of the trees and 119 would be good again. The guys said no, that if they moved the dish "left" 30 feet it would have to be repointed to the right and that 119 would would still be fouled by trees.

I said OK. There are 2 trees that are too close to the house that should be removed and this will fix the problem. On top of that I only get HDNET and ESPN2HD from that satellite and I can live without the DeuceHD until football season, but I'm curious. Are these guys right? Seems to me like its a trig problem where the angular change will be arctan 30ft/26000mi and thats a pretty small angle. What am I missing here?
Use Dishpointer.com and enter your address, use the picture option and play around. it will show you anything in the way.
 

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Éminence grise
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8,473 Posts
oldengineer said:
My roofs peak line is at about 250 azimuth. The roof is 36 feet wide. The 5LNB dish sits at the right rear corner of the house. There is a tree line which runs almost parallel to the peak up the right side of the house. I've got a leaf problem with the 119 satellite, which is at azimuth 247 from my home in Estern PA. I had a DTV tech and supervisor in today. I wanted them to move the dish to a front corner, in effect moving the dish 30 feet towards the south (250 - 90). My reasoning was that the satellites are 26000 or so miles away and that there would be no parallax correction required for a 30 ft move. The dish would be clear of the trees and 119 would be good again. The guys said no, that if they moved the dish "left" 30 feet it would have to be repointed to the right and that 119 would would still be fouled by trees.

I said OK. There are 2 trees that are too close to the house that should be removed and this will fix the problem. On top of that I only get HDNET and ESPN2HD from that satellite and I can live without the DeuceHD until football season, but I'm curious. Are these guys right? Seems to me like its a trig problem where the angular change will be arctan 30ft/26000mi and thats a pretty small angle. What am I missing here?
Per this post from SatelliteRacer (who is a reliable source), you might not have to worry in a few more weeks.
 

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Godfather
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427 Posts
oldengineer said:
The guys said no, that if they moved the dish "left" 30 feet it would have to be repointed to the right and that 119 would would still be fouled by trees.

Seems to me like its a trig problem where the angular change will be arctan 30ft/26000mi and thats a pretty small angle. What am I missing here?
Hahaha... this is funny! The installer and his supervisor obviously never took trig. You're not missing anything. The difference in the pointing angle would be very, very, extremely (did I mention very?) small.
 

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Godfather
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367 Posts
Well, the difference would be "slightly" greater since it is closer to 22,300 miles than 26,000 miles, but certainly not such that a 30 foot move would have any noticable change in dish direction.
 

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Godfather
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427 Posts
I did a quick calculation (with the correct 22,300 miles) and the pointing angle would change by about 0.000015 degree.

If the dish is moved to the other end of the roof the pointing will need to be "touched up" because it has been reinstalled, but the issue of trees still blocking the LOS path to the satellite would certainly not be an issue.
 

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Godfather
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455 Posts
Discussion Starter · #8 ·
jimht said:
Oldengineer,
It's kind of small so I can't tell. Is that the Seawolf?
Nope, its the USS Barbero SSG-317. The bubble aft of the superstructure was a hanger that held 2 Regulus missiles. I qualified on her on Sept 13, 1960. I noticed from the avatars that there are several submariners in this group so add me to the list.
 

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Godfather
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499 Posts
Scott in FL said:
I did a quick calculation (with the correct 22,300 miles) and the pointing angle would change by about 0.000015 degree.
Hmmmm. Six decimal places of a degree. NASA might worry, but I don't think you should.
 

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Cool Member
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Scott in FL said:
I did a quick calculation (with the correct 22,300 miles) and the pointing angle would change by about 0.000015 degree.

If the dish is moved to the other end of the roof the pointing will need to be "touched up" because it has been reinstalled, but the issue of trees still blocking the LOS path to the satellite would certainly not be an issue.
You're forgetting he's in Pennsylvania, not at the equator so the distance would be more like 23300. Using sin(x) ~ x

(30/(23300*5280))(360/2*PI)= 1.4E-5 degrees
 
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