| Author |
Message |
dave
Guest
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 Posted:
Tue Sep 20, 2005 4:08 pm Post subject:
Look Angle vs. Elevation - Does Satellite beam signal higher |
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I recall reading that a Direct TV satellite dish actually recieves the
signal from the satellite at an angle that's higher then the dishes
angle.
My dish needs to be at pointed at 33 degrees elevation. Is the "look
angle" higher then this angle and by how much? I thought the actual
signal comes in at a higher angle, reflects off the dish, and onto the
LNB pickup.
So if the dish is at 33 degrees, what is the angle of the satellite
beam?
I need to clear some trees so need the angle to the satellite vs angle
of the dish. |
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irwell
Guest
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| Posted:
Tue Sep 20, 2005 4:08 pm Post subject:
Re: Look Angle vs. Elevation - Does Satellite beam signal hi |
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On 20 Sep 2005 07:37:17 -0700, "dave" <davefr@gmail.com> wrote:
| Quote: | I recall reading that a Direct TV satellite dish actually recieves the
signal from the satellite at an angle that's higher then the dishes
angle.
My dish needs to be at pointed at 33 degrees elevation. Is the "look
angle" higher then this angle and by how much? I thought the actual
signal comes in at a higher angle, reflects off the dish, and onto the
LNB pickup.
So if the dish is at 33 degrees, what is the angle of the satellite
beam?
I need to clear some trees so need the angle to the satellite vs angle
of the dish.
|
90 degrees minus your latitude will give you an approximation
of the elevation. |
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Lorenzo
Guest
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| Posted:
Tue Sep 20, 2005 9:15 pm Post subject:
Re: Look Angle vs. Elevation - Does Satellite beam signal hi |
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If you can tell me the longitude and latitude of your receive site I can
look up the elevation and azimuth to the Direct satellites.
--
Lorenzo, Posted this message at http://www.SatelliteGuys.US |
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Bill Henley
Guest
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| Posted:
Tue Sep 20, 2005 10:23 pm Post subject:
Re: Look Angle vs. Elevation - Does Satellite beam signal hi |
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dave wrote:
| Quote: |
I recall reading that a Direct TV satellite dish actually recieves the
signal from the satellite at an angle that's higher then the dishes
angle.
My dish needs to be at pointed at 33 degrees elevation. Is the "look
angle" higher then this angle and by how much? I thought the actual
signal comes in at a higher angle, reflects off the dish, and onto the
LNB pickup.
So if the dish is at 33 degrees, what is the angle of the satellite
beam?
I need to clear some trees so need the angle to the satellite vs angle
of the dish.
|
You can get the Az and elevation for a location at
http://www.dbsforums.com/azel.html and if that (or your receiver) says
the elevation is 33 degrees, it means that the signal will be coming in
at that angle. The arm holding the LNB isn't pointing at that angle -
the arm will be over 20° LOWER in elevation. When the dish is at a 33°
elevation, the arm will only be 11-12° elevation from the ground. The
"arm elevation" isn't ever used. You don't want to point the arm at
33°, you want to use the elevation scale on the dish. What you remember
reading is that the dish reflecting to the LNB is higher than the
elevation of the arm itself.
We are coming up on solar conjunction time and in a couple weeks, you
could just look at the sun at the precise time for your long and lat to
see exactly where each satellite is located. It would be an excellent
time to check if you are going to cut trees.
http://perso.numericable.fr/~gjullien/satellite.htm will give you the
date and time when the sun (and/or the moon) will next be at the
appropriate Az and/or elevation. If you enter your Long/Lat into the
Java applet and select 101 WEST for the Satellite, then click Calc 1st
date, I get Oct 7th as the 1st day the sun will be exactly at the right
Az AND elev but today at 10:40, the sun will be at the right elevation
(wrong Az). It lists other times when the sun/moon will be close to
either Az or elev. Repeat for other sat locations you want to get.
--
Bill Henley |
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Bob Nielsen
Guest
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| Posted:
Tue Sep 20, 2005 10:31 pm Post subject:
Re: Look Angle vs. Elevation - Does Satellite beam signal hi |
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dave wrote:
| Quote: | I recall reading that a Direct TV satellite dish actually recieves the
signal from the satellite at an angle that's higher then the dishes
angle.
My dish needs to be at pointed at 33 degrees elevation. Is the "look
angle" higher then this angle and by how much? I thought the actual
signal comes in at a higher angle, reflects off the dish, and onto the
LNB pickup.
So if the dish is at 33 degrees, what is the angle of the satellite
beam?
I need to clear some trees so need the angle to the satellite vs angle
of the dish.
|
The angle to the satellite is "close" to the angle indicated on the
gauge on the side of the mount. It is higher than a line perpendicular
to the face of the dish by about 20 degrees, since the dish uses an
offset feed (to avoid blockage by the LNB and its support arm). |
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Tommy Igoe
Guest
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| Posted:
Tue Sep 20, 2005 11:15 pm Post subject:
Re: Look Angle vs. Elevation - Does Satellite beam signal hi |
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Bill Henley wrote:
| Quote: | dave wrote:
I recall reading that a Direct TV satellite dish actually recieves the
signal from the satellite at an angle that's higher then the dishes
angle.
My dish needs to be at pointed at 33 degrees elevation.
I need to clear some trees so need the angle to the satellite vs angle
of the dish.
You can get the Az and elevation for a location at
http://www.dbsforums.com/azel.html and if that (or your receiver) says
the elevation is 33 degrees, it means that the signal will be coming in
at that angle. (snip)
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This is why they are called "Off set" dishes.
If you need to "clear the trees" before installing the dish, then you
have to know the angles and stuff that your satellite needs to "see."
Your receiver GIVES you that info in the "set-up" once you punch in your
zip code.
Once you know that:.......
At least, get a decent compass with an inclinometer built in, so that
you can "survey" the area you are in, so as to find the perfect place(if
any) to mount the dish.
How else can you know where to mount it?
Remember.... TREES GROW! :)
Once you have the data that DTV tells you to have,regarding the
antenna/dish pointed, it's up to YOU to make sure that the mount is
PERFECTLY plumb!
And I do mean perfectly!
If yer mount is not PERFECTLY straight up-n-down on all planes, then
each and every other "correction" becomes extremely difficult to dial in.
If you have a clear shot, then the dish can be assembled well before you
even bring it to the "perfect mount" with the given elevation already
"snugged down", and then just slip it onto the mount.
Within a few moments of azimuth adjustments, you should have SIGNAL!
Fine tune for better elevation, azimuth, and of course skew, and yer
set.... after all, those are stamped steel parts made by pretty cheap
and inaccurate machines, and fit like loose moose crap.
Having been an installer for MANY different satellite systems, I relied
on one simple tool to "SURVEY FIRST".
http://www.gourmet-ent.com/products/sat.html
I do not work for this company, but I sure as hell do think this is a
GREAT tool for the working man that installs sat dishes!
They are calibrated VERY accurately, centered aroundthe location that
one lives and works in, in a 100 mile circumference.
This is a SURVEY TOOL that is second to none!
Its design is PERFECT and so simple.
It has never let me down once!
But it's not for the one time home installer, as it costs a 100 bucks.
It's a "SURVEY TOOL" that is used to see if crap is in the way!
Way easier to use than a Compass and inclinomter, even if I don't know
the exact area I am. |
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Gary Tait
Guest
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| Posted:
Wed Sep 21, 2005 12:08 am Post subject:
Re: Look Angle vs. Elevation - Does Satellite beam signal hi |
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"dave" <davefr@gmail.com> wrote in news:1127227037.473635.160080
@z14g2000cwz.googlegroups.com:
| Quote: | I recall reading that a Direct TV satellite dish actually recieves the
signal from the satellite at an angle that's higher then the dishes
angle.
|
To the face of the dish, yes, the satellite is higher.
| Quote: | My dish needs to be at pointed at 33 degrees elevation. Is the "look
angle" higher then this angle and by how much? I thought the actual
signal comes in at a higher angle, reflects off the dish, and onto the
LNB pickup.
|
The guage on your dish is calibrated to account for the offset of the dish,
so you set the dish to the guage making the charts/calculators give.
33 degrees is the actual angle you the top of the dish looks at. |
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