Offset dishes and the elevation angle question.

[keller814]

OK quick question. The Phase threes(I am assuming this is the basic dish that I will be getting from Directv) are offset dishes right? If my elevation angle is supposed to be 45' then is that including the 20' or so offset angle?

If what im thinking is correct the the dish will appear to be looking 25, but really looking at 45?

Sorry for my ignorance on the subject, but Im learning.

 

[charper1]

Correct; the signal comes in from a higher angle, not in a direct LoS like a prime focus dish. I am not 100% sure if its a 20° difference though; maybe that figure is different based on the specific dish?

 

[Lynskyn]

If the elevation angle is 45, then set it to 45 on the mount. Yes, the dish will appear to be looking closer to the horizon, but the signal comes in at a higher angle and reflects to the feedhorn, unlike a concentric dish.

 

[jim tressler]

So if I understand this, are the new birds are "higher" in the sky, or are they on the same level as the others.. I realize that they at different locations - ie.. left and right (azmuth) , but what about angle (elevation) - they should be level with each other... does that make sense?? The reason is - my brother in law was getting the upgrade to the at-9 today - aside from showing up at 5:30pm (1-5 window) the installer said the new dish would not work becuase the new sats were lower in the sky and there were trees in the way.. I just think he was lazy - after 5 and he did not want to get the meter out.. They currently have the duel lnb and have no problems with the 119 or the 110.. or is it 101? Was the installer lazy or correct.. I vote lazy.. thanks

jim

If the elevation angle is 45, then set it to 45 on the mount. Yes, the dish will appear to be looking closer to the horizon, but the signal comes in at a higher angle and reflects to the feedhorn, unlike a concentric dish.

 

[raoul5788]

So if I understand this, are the new birds are "higher" in the sky, or are they on the same level as the others.. I realize that they at different locations - ie.. left and right (azmuth) , but what about angle (elevation) - they should be level with each other... does that make sense?? The reason is - my brother in law was getting the upgrade to the at-9 today - aside from showing up at 5:30pm (1-5 window) the installer said the new dish would not work becuase the new sats were lower in the sky and there were trees in the way.. I just think he was lazy - after 5 and he did not want to get the meter out.. They currently have the duel lnb and have no problems with the 119 or the 110.. or is it 101? Was the installer lazy or correct.. I vote lazy.. thanks

jim

They are all in the same path, directly above the equator at 22,500 miles.

Chip

 

[dishcomm]

So if I understand this, are the new birds are "higher" in the sky, or are they on the same level as the others.. I realize that they at different locations - ie.. left and right (azmuth) , but what about angle (elevation) - they should be level with each other... does that make sense?? The reason is - my brother in law was getting the upgrade to the at-9 today - aside from showing up at 5:30pm (1-5 window) the installer said the new dish would not work becuase the new sats were lower in the sky and there were trees in the way.. I just think he was lazy - after 5 and he did not want to get the meter out.. They currently have the duel lnb and have no problems with the 119 or the 110.. or is it 101? Was the installer lazy or correct.. I vote lazy.. thanks

jim

Where do you live?....Which dish are you supposed to be getting?...

 

[jim tressler]

he is in cincinnati and is supposed to get the at-9

 

[dishcomm]

he is in cincinnati and is supposed to get the at-9

Ok..I vote lazy.....
The dish points to 93/101/103/110/119
If I understood correctly he has a the DTV 3 sat dish?....
93 is higher in the sky than 101 and 103 being so close to 101 should be no problem either...
I suggest he call DTV and get a second opinion on the LOS...If it is good then I would find out who the original tech was that called a no line of sight ans retrain the lad..Or send him out the door......

 

[jim tressler]

thanks dishcomm - he currently has the 2lnb - not the 3.. but if you are saying 93 is higher, then it should be a no brainer..

 

[dishcomm]

thanks dishcomm - he currently has the 2lnb - not the 3.. but if you are saying 93 is higher, then it should be a no brainer..

The farther east the sats are located, the higher in the sky they are....for instance..The 61.5 for your lat/lon is 39 degreesEL...105 (we're headed west) is 38 110 is 36 degrees, 119 is 31....and so on..for your area that is...

 

[psyclops]

In my market, the 5-LNB Ka/Ku ODUs are equipped with 99/101/103/110/119 LNBs (that's 99 degWest, NOT 93). As a rule, since all the satellites are in geostationary orbit (over the equator , at 22,236 miles over mean sea level) , and are situated over the Pacific Ocean at least 800 miles of the coast of South America, and being our planet is essentially spherical, the further west the satellite is (higher longitudinal numerical designation) the closer it is to the HORIZON (not to the EARTH, but to the horizon).

In all US markets, the difference in angular elevation among the two extreme satellites of a DTV multisat dish is substantial, sometimes as great as ten degrees.

That being said, if there already exists a triple-sat dish (101w/110w/119w) with clear line of sight to the 3 birds, generally a 5-sat dish swap would not present any additional LOS complications. This is because the 99w and 103w birds are relatively close to the 101w bird, and because the 103w bird is situated between the 101w and the 110w. However, IF THE INSTALLER CAN PROJECT ESTIMATED TREE GROWTH THAT COULD POSSIBLY OBSTRUCT LINE-OF-SIGHT WITHIN 12 MONTHS OF UPGRADE, HE WILL NOT PERFORM THE UPGRADE because DirecTV will back-charge him his full amount after they let you break your contract.

 

[raoul5788]

The farther east the sats are located, the higher in the sky they are....for instance..The 61.5 for your lat/lon is 39 degreesEL...105 (we're headed west) is 38 110 is 36 degrees, 119 is 31....and so on..for your area that is...

Not if you are on the west coast, then the eastern sats are lower than the western ones.

 

[Mr Tony]

The farther east the sats are located, the higher in the sky they are....for instance..The 61.5 for your lat/lon is 39 degreesEL...105 (we're headed west) is 38 110 is 36 degrees, 119 is 31....and so on..for your area that is...

it all depends on location. The longitude will let you know what satellite is highest in the sky (also known as true south satellite). So in MN, my TS satellite is 93 (45N 93W). So in my case 93 is at 38.5 degrees and 61.5 is at about 29

119 & 110 in my area are higher than 61.5
(148 is at a 16 elevation)

 

[psyclops]

You are so correct. I forgot how expansive our continent is, and how laterally displaced its southern neighbor is. In short, I was thinking that South America is due south of North America, when in essence it's really southeast; most of its west coast is further east than our own east coast. I (incorrectly) was thinking the True South Satellite to be westward for all of N.Am as it is for S.Am. Thank you Raoul and Iceberg for catching this early.

-Psyclops

 

[dishcomm]

In my market, the 5-LNB Ka/Ku ODUs are equipped with 99/101/103/110/119 LNBs (that's 99 degWest, NOT 93). As a rule, since all the satellites are in geostationary orbit (over the equator , at 22,236 miles over mean sea level) , and are situated over the Pacific Ocean at least 800 miles of the coast of South America, and being our planet is essentially spherical, the further west the satellite is (higher longitudinal numerical designation) the closer it is to the HORIZON (not to the EARTH, but to the horizon).

In all US markets, the difference in angular elevation among the two extreme satellites of a DTV multisat dish is substantial, sometimes as great as ten degrees.

That being said, if there already exists a triple-sat dish (101w/110w/119w) with clear line of sight to the 3 birds, generally a 5-sat dish swap would not present any additional LOS complications. This is because the 99w and 103w birds are relatively close to the 101w bird, and because the 103w bird is situated between the 101w and the 110w. However, IF THE INSTALLER CAN PROJECT ESTIMATED TREE GROWTH THAT COULD POSSIBLY OBSTRUCT LINE-OF-SIGHT WITHIN 12 MONTHS OF UPGRADE, HE WILL NOT PERFORM THE UPGRADE because DirecTV will back-charge him his full amount after they let you break your contract.

99 degrees..I stand corrected..Just looked it up...Thanks..
Now as far as LOS is concerned...In some instances the amount of sky required for multi sat reception is not possible on some properties....
Most customers are understanding..Some are not but they grumble and let it go....Some, in rare cases, can get unreasonable and in extreme cases, beligerrant.....These are people who insist we install the sytem to "prove" to them we are correct.....Of course nobody in their right mind is going to waste 2-4 hrs of their time to come to a conslusion they already are certain..
However in this thread staters case, the excuse used by ther tech was lame...at least that's my judgement based on the info given...

 

[psyclops]

I concur.

I was incorrect in my last post when I stated that the further West the satellite is, the closer it is to the horizon. That statement is factual only in the eastern part of the country. In the west, the opposite holds true (thanks Raoul5788 and Iceberg).

 

[jcolombo]

I concur.

I was incorrect in my last post when I stated that the further West the satellite is, the closer it is to the horizon. That statement is factual only in the eastern part of the country. In the west, the opposite holds true (thanks Raoul5788 and Iceberg).

Actually, it is more correct to say that satellites EITHER east or west of the receiving station's location are closer to the horizon. Satellites line up in an arc (the geostationary orbit around the equator). If you lived at the equator, this arc would be directly overhead - that is, your satellite dish would point STRAIGHT UP and then would move directly left or right toward the horizon (!). For us in N. America, the arc is tilted to the south because the equator is south of us; how far the arc is tilted depends on how far north you are. So satellite dishes in Miami point much higher in the sky than dishes in Seattle. But wherever you are, the satellite that will appear highest in the sky to you is the one directly over your head, which is the one at the same longitude as you are. Satellites to the east or west of that longitude will appear closer to the horizon because the line of the arc falls toward the horizon on each side.

For example, I live in Champaign, IL, with a longitude of 88 degrees (roughly). For me, the satellite highest in the sky would be one located at 88 degrees west longitude (Actually, Nimiq 1, one of Bell ExpressVu's satellites for its Canadian DBS service is at 91 degrees, is pretty darn close). Anything east or west of 88 degrees will be closer to the horizon. So for me, the DirecTV satellite at 119 west is 31 degrees west of my location and is actually LOWER in the sky (closer to the horizon) than the DISH satellite at 67.5 degrees, which is only 20.5 degrees east of my location. In Los Angeles, which is at a longitude of 118 degrees west, the 67.5 sat is 50.5 degrees east, which will appear quite low in the sky, while the 119 satellite will be highest in the sky and almost exactly due south. In New York City, at a longitude of 74 degrees west, the 67.5 sat will be very high in the sky, while the 119 sat will appear much lower. Note, however, that since LA is further south (toward the equator) than NYC, a satellite dish in LA generally will point higher in the sky than a dish in NYC.

So . . . the exact elevation that a receiving dish must point at depends on two factors: how close the satellite that you want to point at is to your longitude AND how close you are to the equator. The closer the satellite is to your longitude, the higher the elevation, and the closer you are to the equator, the higher the elevation.

John C.