Elevation Angle - UpsideDown - Offset 1.2m Dish

Discussion in 'C-BAND Satellite Discussion' started by Y-Naught, Mar 3, 2013.

  1. Y-Naught

    Y-Naught Topic Starter Member

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    Hello, this is my first post. If I've miscategorized this question, please redirect it. I am new to this, but please know that I've been researching and researching for a very long time, and I have seen other threads similar, but not quite exact - and I honestly could not translate that into exact what I'm trying to do. I see 10 different answers per thread and it's gotten me so confused about this elevation angle I honestly have to ask directly. Some have said just try and play around with it, and I have - but with no success, so here I am.

    Notes:
    - My wild guessing randomly picked up 99W Galaxy 16 ABC Puerto Rico once, and I can't tell you how but since I've moved it I could never get it back.
    - I also have an existing tiny (36 cm?) Ku dish that I know works and was able to pick up 3 community service channels on, to prove my openbox was working.

    Setup:
    -1.2m Offset dish (required for the satellite I want according to satbeams was 110 cm, so I'm fine - since ABC needed apparently a 150 cm dish to pick up and I did it with a 120, I feel I should be able to easily get the satellite I want that requires a 110 cm dish)
    - Combined C/Ku band LNBF (I only really care about the C-band though, the Ku is just a bonus)
    - Fixed (albeit moveable if necessary) mount
    - Openbox S11 which I programmed all the transponders on Dr Sat/Lyngsat/Sathint into
    - I have added all C transponders to one list with what it called "LNB Freq" set at 5150, and the same with close-by Ku transponders set at 10600 and separate at 10750
    - I removed the external diseqc switch altogether and directly connected to JUST the C-band (lower) LNB output
    - Want to hit Anik F1r at 107.3W / 29° elevation
    - Dish has 24.62° offset

    Okay so this is my setup, please tell me if anything above is wrong. The main question I have though is definitely this problem....
    I have heard/read a dozen different ways to set offset dishes upside down. Why do I have to set it upside down? Well, I need 29° elevation, and if the offset is 24.62°, then that means:

    29° - 24.62°= 4.38° ... which is impossible, it just wont go that low. There's a bar to the base that it hits. (If that's not how it's calculated, please let me know) It makes sense to me because the mini one is essentially vertical.

    So I needed to put it upside down, and through my research found multiple answers.

    1st: 90° - 4.38° = 85.62° (this one said that by rotating the dish so the lnb was on the top then you just count the offset angle bracket from 90 backwards)
    2nd: 29° + 24.62° = 53.62 ° (this one basically said, since it started at -24.62°, to get it to "zero" you'd have to add the offset of the dish; IE 24.62°)
    3rd: 24.62° x 2 + 29° = 78.24° (this one I didn't even have a clue why it was double, but I assume maybe it's because the angle is based on 90° times 2 and totating the dish 180°, IE upside down to get equivalent of 180 degrees instead of the 90 scale on it you have to double it, but I really could be waaaay off)
    4th: That it's simply 4.38° , since it's only rotated 180 degrees and it's just reflecting off the bottom instead of the top...


    The first and second made the most sense to me, but alas I never did manage to hit Anik F1r. I really don't even need to know WHY which method works, just please let me know which of these is applicable. All I did is rotate my dish (not the angle bracket or anything else) exactly 180° so that the lnb was on top and not touching the ground sitting at 12° which was still too high since I needed 4.38°....

    Thank you so much in advance, and sorry for the long ramble - I just want you to know what I have so it can be applicable.
     
    #1 Y-Naught, Mar 3, 2013
    Last edited: Mar 3, 2013
  2. primestar31

    primestar31 SatelliteGuys Master

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    The elevation settings stamped into the back adjuster already compensate for the dish offset. That means if you need 29 degrees elevation (the satellite you are aiming for is at 29 degrees), and if the pole the dish is mounted on is level in all directions, simply set the dish at the 29 degree setting....

    No magic, you are over-thinking the issue.
     
  3. Y-Naught

    Y-Naught Topic Starter Member

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    Wow, okay thank you. So I need to set the satellite (if it wasn't upside down) at 29° when dishpointer says to use exactly 29° elevation angle? What about when it IS upside down though?
     
  4. primestar31

    primestar31 SatelliteGuys Master

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  5. Y-Naught

    Y-Naught Topic Starter Member

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    Alright so the 2nd method I listed WAS right after-all lol. Thank you. Maybe I'll actually hit that bird finally this time :p
     
  6. FaT Air

    FaT Air HOA Free Zone

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    Inverted, in pictures

    Here' a diagram I threw togerher
    [​IMG]
    So double the offset angle, add the elevation required and you have the elevation scale reading when inverted.
     

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  7. phlatwound

    phlatwound FTA Bumpkin
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    Y, lots of good info in this thread but I would add...apply the numbers to your elevation scale, but just use it as a starting place.

    The scale may be right on the money, then again some of them are off by several degrees.
     
  8. Y-Naught

    Y-Naught Topic Starter Member

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    See this is why it's soo confusing - I have 1 person say to add the offset plus the 29° from dishpointer, and you said to double the offset and add 29°. But if according to your images I start at -24° upside down, and I want +29.... for clarity why would I add a 2nd 24°? -24 to 0 is 24, and 0 to 29 is 29....so isn't that 24+29? .... >.< Sooo confused. OR is it that there is some hidden 2nd 24 degrees in the offset from the bracket because the angle of the bracket is already off another 24° or something???
     
  9. waylew

    waylew SatelliteGuys Pro

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    As it is unnecessary to have the dish inverted for what you want,remove the confusion and reinstall the dish as it should be.Set it to 29 and other than a little tweaking you're done.
     
  10. Lone Cloud

    Lone Cloud SatelliteGuys Pro

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    I can appreciate how some guys need to have mathematical exactness, but I have rarely seen those people get quick or precise results. From your post it looks like you will not be trying to track the arc, but are going with a fixed system - one dish aimed at one satellite.

    You don't say whether your receiver has a beep on scan function, but some do. Mine does. I don't use a single inclinometer to aim my dish. I set my receiver for the satellite I want, and for a hot transponder on that satellite. I set the receiver to beep on scan and hook the sending unit for wireless headphones into the audio out of the receiver. Then go to the dish, switch the headphones on and move the dish around until I get the strongest beep signal. Then tighten all nuts and bolts.

    I can't tell you how many times people have posted in frustration at doing complex angle and directional calculations and coming up with nothing. It's simple. There is a fixed spot in the sky where the satellite you want is located. Hit that spot and a lot of receivers can be made to beep. Strongest beep means it's aimed. No protractors, inclinometers, formulae or vectors necessary.
     
  11. FaT Air

    FaT Air HOA Free Zone

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    As can be seen in the picture, when the dish face is vertical, the dish looks 'up' offset degrees. And the elevation scale reads the 'offset degrees'. Let's say its 23 degrees.
    Now when it's inverted, the scale still reads 23 degrees, but the dish actually 'looks' down. It's looking at -23 degrees.
    The difference between the two is 46 degrees. (double the offset)
    The above is using the elevation scale on the mount as the reference.
    The other post linked to references a angle finder on the face of the dish. apples to oranges kinda.
     
  12. Anole

    Anole SatelliteGuys Master

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    I'm with Lone Cloud.

    Many years ago, I got half a dozen dishes & LNBFs.
    They were new in boxes, so I figured nothing could be wrong with the reflectors.
    I -was- a little concerned about the LNBFs, so I tested them before sending half to a friend.
    Put each LNBF in turn, on a single dish, and pointed it at the sky.
    Used a $10 DBS meter, and had no trouble getting a strong signal from each.
    And that was HAND HELD; no pole involved! ;)

    Just takes confidence, and the right equipment.
     
  13. FaT Air

    FaT Air HOA Free Zone

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    You shouldn't have to invert the dish.
    With the dish face perfectly vertical, the dish is looking up, from the horizon, 24.62°.(the 'offset') To make it 'look' to 29° you have to tip the dish back 4.38°, raising the LNBF. Bottom of dish gets further away from the pole.
    BUT, maybe none of us know what we're talkin about. How about some pictures to clarify the situation.
     
    #13 FaT Air, Mar 4, 2013
    Last edited: Mar 4, 2013
  14. Anole

    Anole SatelliteGuys Master

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    another concern

    Most Ku dishes won't accept a larger diameter C-band LNBF at the focal point.
    If you ignore the error, this creates two problems:
    - it throws off the elevation several degrees
    - it reduces performance of the dish

    Pictures, brand names, and links would be helpful.
     
  15. FaT Air

    FaT Air HOA Free Zone

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    Sorry but I missed that point.
     
  16. Lone Cloud

    Lone Cloud SatelliteGuys Pro

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    Right.

    The only reasons I prefer the wireless headphone method are , firstly, you don't take anything apart at the dish and secondly, your hands are completely free to use wrenches to loosen and tighten stuff.

    I can still remember when I started out in this hobby in 06. I went to all the sites. I tried all kinds of settings. Bottom line is, took me a month and a half to get that little dish aimed - and it wasn't aimed well.

    Now, with the benefit of experience and the education supplied by many mistakes, I can aim a dish perfectly inside of forty minutes - and that counts setting my receiver on the southernmost satellite on a hot transponder, making sure "beep" is on, connecting the wireless headphone sender to audio out, putting fresh batteries in the wireless headphones, getting my tools and ladder out to go on the roof.

    In fact the quickest part of the process is in actually aiming the dish. Loosen "beeep, beep", tighten, done.
     
  17. Y-Naught

    Y-Naught Topic Starter Member

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    ... Sorry everyone...I haven't had a day off work since then... One guy quit and the other person was on vacation so I had to do triple shifts and no time to "play" or work this out....
    It is unfortunately necessary my friend. I can't lower it enough, it hits the reinforce bars for the main post.

    I think from your post it means it's just double the offset to get back to what it was when not-inverted, therefore only add another 4.38° instead of the full 29°, because at double the offset it's then at normal offset of 24.62° and 24.62°+°4.38° hits the 29°

    I really wish I had a camera about now, lol. The problem is, 4.38° is NOT tipping it back, it can't go that far forward, there's a bar in the way.... The best I can get is about as low as 10° on the scale. The scale isn't designed in a way where I can physically set it to the lowest notches on the scale because the dish hits before that. I can't physically set it so the dish is physically vertical because of that.

    If I understand correctly what you're saying here, then that's why I used a conical scaler ring. It looks identical to this one:
    http://galaxy-marketing.com/images/WSKU2C-KIT-1.JPG

    I almost guarantee I have the skew wrong though....

    And to the person who was saying about the beep tone - I'm using a Digital Satellite finder meter with a beep tone and blue led backlights. I never even knew a receiver with this feature existed. I am using an Openbox S11, and I assume it doesn't have this feature, since I've not seen it anywhere before.
     
    #17 Y-Naught, Mar 17, 2013
    Last edited: Mar 17, 2013
  18. Y-Naught

    Y-Naught Topic Starter Member

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    DELETE ... IT won't delete accidental double post??? lol
     
    #18 Y-Naught, Mar 17, 2013
    Last edited: Mar 17, 2013
  19. joeroscoe1957

    joeroscoe1957 SatelliteGuys Family

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    Hi , Y-Naught . what ever you do , don't loose heart . Once you get thru all the "trial & error" , hit those 99w signals again and tune everything on your dish , to max those signal levels , then the fun should began . Until the conical scalar ring is position just right and the lnb skew is close , these small dish c-bands can give you fits . I use a small tv outside with a coolsat 5000 , using a cheap signal meter to figure out where 99w should be , go to manual scan or tp scan , set it to "tp 3845 H 15030" for the Puerto Rico mux & slowly move the dish until the green signal bars fly . For me , that scalar ring works best at the end of the lnb , about like your picture shows it , but the postion (up & down , back & forth) it's tighten to, on the lnb , often makes a big difference . Hope I didn't make it more confusing , (I live confused) , but I love playing with small dish c band , You're upside down 4 ft'r , looks like alot of fun .
     
  20. FaT Air

    FaT Air HOA Free Zone

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    A c band, or a c/ku lnbf, is larger in diameter than 40mm so it will sit higher in the 'saddle' meant for a 40mm ku lnbf throat. This will make the elevation scale on the dish inaccurate. (I've never heard of a small offset dish designed for a C band feed horn. Only hobbyist 'improvised' ones )
    A conical scalar does not correct this. It only focuses the feed horn on the dish.

    There's no need to invert the dish to aim at an elevation of 29°.
    Trying to set the elevation scale to 4.38 for a satellite at elevation of 29 is the wrong way.
    You don't tip it forward. You'd Tip it back from vertical.
    The elevation scale on the mount should be set to 29.
    And with the elevation scale now inaccurate because of the feed placement, think you'll have to raise it an additional 3 or 4 degrees. Maybe more.

    Can't 'see' the what, or 'picture it, that's hitting the other thing. Some pictures would probably explain more than a 1000 words can.
     

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