Satellite Alignment - What angle?

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eXDee

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#97799 21-Feb-2012 00:14

I wasn't sure where to post, but this is a question related to Sky Satellite dishes and i figured the satellite experts would be in here.
I'm looking at doing a bit of a Wok-Fi setup with an Ubiquiti Nanostation Loco mounted on it, and i need to figure out how to align it.

So the question is simply, what angle does the 60cm sky dish need to be, to be horizontal? Standard sky dish with offset feedhorn.
I want to mount a green laser pointer on it for so i can see where its pointing.

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727 posts

Ultimate Geek

#584362 21-Feb-2012 10:02

I don't grasp what it is that you are trying to do (my ignorance, I'm sure), but can you clarify that you are wanting the angle of the physical dish itself, rather than the altitude angle to Optus D1, which will be different due to the offset dish design?

Also, watch where you point that laser; the aviation industry and the police are taking cockpit laser strikes very seriously, and with good reason.

RunningMan

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#584409 21-Feb-2012 11:22

It's been a while since I looked at one, but I think they had an elevation scale on the side of the mounting bracket.

To get a horizontal elevation, the LNB arm will be pointing downhill, and you probably won't be able to use a normal vertical mounting pole, as these are obviously designed to point the dish in the general direction of the sky...

As a rough guide, the elevation angle for Optus D1 (which is where it would have originally pointed) is about 45 degrees in Auckland, and a few degrees less as you head further south. To get horizontal, it therefore needs to tip forward by the same amount - that should get you in the right ballpark.

xarqi

727 posts

Ultimate Geek

#584414 21-Feb-2012 11:29

RunningMan: It's been a while since I looked at one, but I think they had an elevation scale on the side of the mounting bracket.

That's true, but it will be the angle to the satellite, not the angle of the dish.
If the altitude angle is all that is required, there are several resources available to calculate it based on geographical location.
In Auckland, it's about 44.5°.
Here's one: http://www.dishpointer.com/

The OP seems to want (but hasn't confirmed) the physical angle of the dish itself, which will be different, and will depend on the degree of offset used in sky dishes.

RunningMan

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#584424 21-Feb-2012 11:41

xarqi:
RunningMan: It's been a while since I looked at one, but I think they had an elevation scale on the side of the mounting bracket.

That's true, but it will be the angle to the satellite, not the angle of the dish.

Yep, he wants to get it horizontal, so the angle to the "satellite" that he wants will be zero degrees.

xarqi:If the altitude angle is all that is required, there are several resources available to calculate it based on geographical location.
In Auckland, it's about 44.5°.
Here's one: http://www.dishpointer.com/

Which is about the 45 degrees I mentioned. If he takes a dish which is aligned to D1, then pushes it forward (down) by about 45 degrees, it'll be horizontal.

xarqi:The OP seems to want (but hasn't confirmed) the physical angle of the dish itself, which will be different, and will depend on the degree of offset used in sky dishes.

He wants to aim it at a point that is also at about ground level (i.e. approx horizontal). If it has an elevation scale, then he doesn't need to know the offset, you just set the scale to zero. If it doesn't have a usable scale, then he can work from the known start point of it being originally set for an elevation angle of about 45 degrees, then tipping it forward 45 degrees to get horizontal

xarqi

727 posts

Ultimate Geek

#584428 21-Feb-2012 11:51

That'll teach me for trying to be helpful when I don't really understand the question I guess. ;)
Sorry for the digression.

RunningMan

8953 posts

Uber Geek

#584435 21-Feb-2012 11:58

Unless you happened to know what wok fi was, it's not obvious that he's trying to do something with a sat dish that doesn't involve pointing it anywhere near a satellite at all!!

Have a look at this for a bit of background.

xarqi

727 posts

Ultimate Geek

#584439 21-Feb-2012 12:05

RunningMan: Unless you happened to know what wok fi was, it's not obvious that he's trying to do something with a sat dish that doesn't involve pointing it anywhere near a satellite at all!!

Have a look at this for a bit of background.

Oh! Wok Fi!

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RunningMan

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#584448 21-Feb-2012 12:11

xarqi: Oh! Wok Fi!

Good aye

I've never had a go myself, but apparently works quite well with just cheap stuff laying around... There was a guy that (I think) was at Victoria or Canterbury university doing it about ten years ago, and published an article on it, can't find it doing a quick google, but no doubt someone will know...

stevenz

2802 posts

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#584452 21-Feb-2012 12:16

Just use Pringles cans.

@KnightNZ

eXDee

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#584468 21-Feb-2012 12:35

Horizontal is correct. I'm going to be mounting a wifi adapter on it and pointing it at a site 150m away, currently the adapter has heavily fluctuating signal strength so i'm hoping to improve this with the dish. Its an Ubiquiti Nanostation Loco so it's already designed for point to point links, and i'm hoping the dish enhances this if aligned correctly.

This dish is a different one and is newer but i'm using it for reference. It doesn't appear to have a zero. So it seems i need to set it to 20, then angle it a further 20 degrees on the pole?
https://i.imgur.com/3Fd6l.jpg

Jaxson

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#584505 21-Feb-2012 13:12

Mate, just grab a builders level and put it across the face of the dish, forget the offset aspect. Get the face level and attach your wifi receiver down where the lnb was on the arm. Get it going and then tweak from there, as that's essentially what you are doing hunting for a satellite anyway. Horizontal will only work if both broadcast and receive components are at the same height 150m apart. Chances are you're going to have to tweak anyway, so I'd start with the level and go from there.

eXDee

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#584513 21-Feb-2012 13:20

Interestingly enough they are pretty much the same height, the roof of two houses.
I think i'm going to hunt down a protractor or something and try and see if i can get the mount set to 0 by mounting the pole at 20 degrees.

I was just wondering if i could use some kinda of technique to figure out the correct angle for the actual face of the dish at horizontal, then mount a laser (with a ton of duct tape or something? :D) level and use that for aligning.

Don't worry, there will be no pointing at aircraft of any sort. Shine one of those things up in the sky and you give everyone in the city a clear indicator exactly where its coming from. Pretty silly move.

xarqi

727 posts

Ultimate Geek

#584518 21-Feb-2012 13:26

Well, having embarrassed myself once in this thread already, I'm going for the double!

Just tilt the dish down so that from anywhere on a line from there to the "target" it appears circular.

P.S.
Hmm - actually, armed with the major and minor diameter measurements, the offset angle could be calculated I think.

eXDee

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#584522 21-Feb-2012 13:30

Hey, i think that makes sense actually! Although my circle identification skills (?) aren't perfect, that seems like it might be of some assistance.

As for embarrassing yourself, don't worry, its an odd topic probably in the wrong forum (was expecting a mod to come in and move it or something), but since i'm simply talking about the angles of dishes etc, what i'm mounting on it is pretty irrelevant and figured I would find the most informed people here.

eXDee

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#584527 21-Feb-2012 13:34

xarqi: Well, having embarrassed myself once in this thread already, I'm going for the double!

Just tilt the dish down so that from anywhere on a line from there to the "target" it appears circular.

P.S.
Hmm - actually, armed with the major and minor diameter measurements, the offset angle could be calculated I think.

Well i'm not sure what major and minor are, but if you look at the dish front on, its vertical measure is 660mm from top to bottom, and the horizontal measure is 600mm. Its approximately 370mm from the bottom of the dish to where the LNB receiver would be and 620mm from the top of the dish to where the LNB receiver would be. Its 450mm from what i think is the 'middle' of the dish to where the LNB would be.

Ah and if i place a solid ruler across the dish, and then measure the middle to the ruler, that is, the 'depth' of the curve, i get approx 52mm.

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