quick question (and dumb too)

[Dee_Ann]

Ok, I’m trying to get my BUD in proper working order..

Last night I rewired my Gbox ( it was wired backwards w<->e vs e<->w )
and I connected my new meter to it and stepped it through the arc to see what it can see.

It doesn’t seem to see the east and west birds but it sees the birds due south pretty well.

Shouldn’t the dish be aligned PERFECTLY along a line running north/south?

I clamped a loooong stick to the mount and put a precision compass on it and the dish is pointed at 185 on the compass. I would think it should be pointed at 180. Right?



I have the ability to point it with precision rather than simply guessing or “eyeballing it”.

And since it’s not a USALS positioner I ~assume~ that precision aiming is critical. Right?

I figure that I should aim it dead south, 180 degrees then start working on the inclination and declination stuff next. Right?

edit: I went to dishpointer.com and put a pin exactly on the dish in my yard and told it to give me the true north/south info and this is what it gave me. Do I use the second compass reading of 178 degrees? I think it’s something to do with the north pole moving around.

 

[KE4EST]

The ends of your arc are for sure off. I would just start from scratch, on the alignment. If you are rusty on properly aligning a C-Band dish go here and read:
http://www.geo-orbit.org/sizepgs/tuningp4.html#anchor797917

That keeps me from a lot of typing.

 

[KE4EST]

Yes use the 178. Just make sure your compass is not too close to the dish, or is will cause it to read wrong.

 

[gabshere]

the way i do it Dee Ann is go to your first sat that starts to lose signal probably 1 or 2 from your apex (due south sat) then lift up or down on the dish to see where it gains or looses signal. usually its a sign of you being off probably an 1/8 inch east or west ( which means you have to twist the whole dish mount small increments) i try 1/8 at a time.

 

[Dee_Ann]

Yes use the 178. Just make sure your compass is not too close to the dish, or is will cause it to read wrong.

Thanks!

Yes, I clamped a 10 foot stick to the polar mount with some clamp thingies, the board is arrow straight. I have an actual military compass which appears to be highly precise.
I laid the compass on the far end of the stick so it’s 10 feet away from the dish and removed all metal from myself. I loosened the dish and moved it a good bit till the compass reads 178 on the money.
Now I have to pretty much start all over. That sucks because I did some extensive programming on the Gbox last night. Oh well. Here we go again !

 

[beavs2112]

Now I have to pretty much start all over. That sucks because I did some extensive programming on the Gbox last night.

did you know the Gbox has a resync function?

 

[Dee_Ann]

eh, a friend called and wants me to run an errand with her. I was on a roll too. Back in a while. I made some discoveries that the polar mount is not level, the pole is but the mount is not, I see this being a problem so I’ll need some advice on that when I get back.

 

[beavs2112]

basically the gbox resync function is a shift (east or west) of ALL the stored satellite positions. the manual http://www.satelliteguys.us/xen/threads/g.339590/ does a better job of explaining it.

as for the mount being off ... yes it should be level also.

 

[Dee_Ann]

Ok, back home.

I put a digital angle meter against the pole and it’s perfectly plumb at 0.00

I put the meter against the parts of the polar mount and they are NOT plumb at zero.

I would imagine that being out by a few degrees down at the mount will translate to the LNBF being quite a bit out.

I’m not sure what to do about this..

 

[Dee_Ann]

Is there a youtube video that actually shows the process of setting up a C-band dish from start to finish?
The math is causing my brain to hemorrhage. The instructions are written for Phd rocket scientists and there seems to be a disconnect in it all.

I can not process what it is they are trying to say in the text. The graphics look like something scanned in from a 1980 fax that was refaxed a few times first.

I understand the inclination part. Moving forward from that, I experience brain death.

THIS is why I have such a hard time with satellites. I can not do geometry at all. Not even a little bit.

 

[Dee_Ann]

Wait, I think I got it now. One site I was looking at was very confusing and was talking about subtracting something from something else and it made my brain implode.
Another site said to ADD something to something and when I put the angle meter on EVERYTHING I finally figured out that was the right thing to do, to add the numbers.
I found that my dish only has THREE declination settings, period. It was set in the middle one and the numbers were off. So I moved it to a different position and the numbers I got on my meter jived with the added up numbers I found on the calculator site.

Now I have to go out there and tweak it to the new declination and see what that gets me.

This has been very, very confusing for me. I have very bad math skills and I can not deal with geometry at all.
You guys have no idea how easy you have it...

 

[primestar31]

LOL. You have the same problem as Khan!

 

[Dee_Ann]

Very possibly..

Things like driving in reverse are the kiss of death for me. I have been backing my car into my driveway for 15 years and it still gives me grief. Every single time I have to pull back into the street and start over, 5-6 times before I can get the car backed in straight. I do this because unloading groceries and because burglars won’t hit backed in cars but most of all, I have this silly dream that eventually I’ll learn how to do it right on the first try. HA! 15 years of failure says no, that’s not ever going to happen. But like on the dishes, when I start trying to figure out angles and tilting stuff and like the complex dance a dish makes as it moves across the arc so that it skews itself as it moves, that really just does not compute for me. I’m just exceptionally bad at math.. I admit it.

Anyway.. So I tweaked on the dish a little more but called it quits from the heat. It seems to favor birds to the west.

I am absolutely certain that the dish is pointed dead south but there’s the issue of the polar mount not being level/plumb.
The pole is perfectly plumb but the polar mount is off by almost 3 degrees. There seems to be no way to correct that.

So now I’m wondering if that 3 degrees is fatal to this whole project? Does this create a problem that is so great that it’s pointless to continue?
OR, can I compensate for this and still get a 100% usable dish that will track the entire arc?

 

[beavs2112]

I am absolutely certain that the dish is pointed dead south but there’s the issue of the polar mount not being level/plumb.
The pole is perfectly plumb but the polar mount is off by almost 3 degrees. There seems to be no way to correct that.

Dee Ann the best way I know (done it several times) to correct a unlevel mount is what gabshere is doing in this http://www.satelliteguys.us/xen/threads/dvb-s2.340004/#post-3494954 thread .... READ post# 8 from Primestar. Gabshere has a pic farther down on how it should look. Good luck

 

[Dee_Ann]

This is pretty much what I have.

But I’m guessing that the polar mount stuff wasn’t welded perfectly square.



The little paint program is ultra basic and doesn’t have a way for me to easily draw the image above showing the tilted hardware.

The pole sleeve only has two bolts in it, on the east side. That’s a pretty lame design. I would think a proper, well thought out design would have bolts all around so you can adjust it properly.

So I need to go stick angle meters all over the stupid thing so I can see everything at the same time.
I’m trying to imagine putting shims in there, somehow. I am thinking I need to put a shim on one side at the top and the opposite side at the bottom to force it to tilt to (hopefully) counter the problem.

I haven’t worked out which side needs to tip which way because I’m not sure of the readings and need to check everything all over again.

Ok, I used a different paint program to distort the hardware (assuming it was welded up un-square) then tipped the image to illustrate the “fix”...

There are little red lines in there that would be the shims. Does this look right? Or even make sense? In my mind it sort of does but I’m still not there yet with the exact, final details.
In my drawing I may have them backwards but I’m thinking this is the general idea of what I need to do, right?

Also, this is what the online calculator told me I needed to set the dish to..

From what I could figure, (ASSUME) I take the 30.6 and ADD the 4.33 to it to get 34.93

On the dish there are only three possible declination settings. There is a flat metal bar with three holes drilled in it.
I thought it was a slot that you could move it up and down any way you liked but this was not at all the case.
You can only select one of the three holes. It was on the middle hole and the reading on the declination was off.




So I pulled the bolt and dropped it down a little to the top hole and bingo, all of a sudden the declination on the dish gave me a reading of 35 degrees! ZING!
So that was waaaaaaaay off, it’s been off since day one, several years ago when I put the thing up in the first place. I didn’t understand back then what or how so
I put it together wrong in the very first place.

I need to get this crooked polar mount fixed now. After that I assume I will need to set the inclination to the 30.6, then aim at my southern most satellite Galaxy 3C, and then start tweaking the LNBF, right?
Because I know that the LNBF can be out of whack too. There is no 100% square on target way to simply tighten bolts down and it be on the money like KU stuff.

But anyway, I guess right now the demon I need to vanquish next is the crooked polar mount.

 

[gabshere]

sounds like you've been working on it i can post more pics

i would agree the more bolts the better mine has it on all sides -1 so 7 tightening bolts .


your top bolt will be the shim, so you don't need that one just a small shim on the bottom you would just need to tighten the top bolt first with shim at bottom.

1 pic is mount base with shim ( 0.7 degrees off) even with shim , 2 & 3 are both sides, 4 th is crossmember showing 88.1

 

[DVB-S2]

I have a digital inclinometer very similar to the one in your picture. I have concerns about its accuracy (and most other digital inclinometers, too). These things can be calibrated - you set the on a "level" surface and press the 'calibrate' button. But what is a "level" surface? If I use the countertop in my kitchen, I find it varies by +- 0.2 degrees, depending on where I place it. What can an amateur use as a reference level? A bubble level? How accurate are they?

You may say that a digital inclinometer should be perfectly calibrated when you buy it, but is that true?

In short, Dee-Ann, you think your mount is off by 1.3 degrees, but is it really?

P.S. This is my first contribution to this forum, but I've been around FTA for quite a while...

 

[Dee_Ann]

Good question.

Let me also add this. A few years ago I paid a guy to put the poles in the ground for my C-band dishes. He, being a guy, didn’t care much about being bossed around by a woman and insisted that he knew what he was doing and that I should just let him do his job without “helping”.. He told me he was going to charge me extra if I helped.
I told him I wasn’t going to pay him at all if he didn’t follow my directions. So we got that sorted out PDQ...

The problem was that he was putting a bubble level against the pole and he declared it was “good to go” and “all done”..
So I double checked and I saw that he had set the pole where the bubble was technically between the lines but it was touching one of the lines and wasn’t truly centered or level.
He had set it at “good enough” rather than level. I stuck two levels to the pole and I shoved on the thing until it was absolutely perfectly level both ways. He said that was overkill. I said “Yeah and it’s MY satellite dish that’s going on here.”

Some people have different interpretations of what is level, square, plumb, etc..
I like the digital meter in that it can be precise but I don’t know if it’s calibrated or not, my house is not even remotely level (tree roots) so there’s nothing here I can use to set it by.
I can try to calibrate it to the pole but it may be off by a fraction since bubble levels were used. When I put the digital meter against the pole it does read zero point zero zero so I’m hoping it’s right.

I also have no way to know if the pole is bent or not. A few months ago I bought a 10 foot piece of electrical conduit and I had to dig through them to find one that was straight. Almost all of them had substantial bending, enough to render them useless for satellite LNBF arms.

I have an iPhone with all sorts of digital levels but the problem with that is the case is not square, it has roundy curves so you can’t really put an edge of it against something squarely. So using it as a level is pretty useless.

The little digital angle meter seems to be a bit finicky so I’ve take to clamping it to stuff with those clamp things (sooooooo handy!!) and it seems to work better when I do that versus just holding it against something with my hand or relying on the very weak little magnets built into it. I think I want to shop for a higher quality version of it, this was a Harbor Freight gadget my dad gave me, he had it for several years so I don’t know how many times it’s been dropped or not.



I have a few of those stick on mechanical angle meters but they are large and bulky and don’t fit well in a lot of places. They are also very wiggly so when you touch it you have to leave it to sit for about a minute before it quits moving. That’s a bit annoying..

 

[DVB-S2]

One approach to calibrating your inclinometer would be to buy (for later return) a high-end digital inclinometer and use that to create a 'reference' level surface (but this assumes, of course, that it is accurately calibrated).

Another method (I just thought of) would be to put your inclinometer on a smooth, flat object and set it to level with the inclinometer. You then turn the inclinometer around 180 degrees, and in theory, it should still read perfectly level. If it doesn't, then the inclinometer will be showing twice the angle by which it is off calibration (in theory!). For example, if it reads 0.0 in one direction and 1.4 in the other, then it is out by 0.7 degrees. You would then tilt the flat surface until the inclinometer read 0.7 degrees and press the 'calibrate' button. Obviously, you should apply the above test again until you get a reading of 0.0 in both directions. I'll have to try this out on mine tonight

I agree about the need to clamp these inclinometers - they don't like any shaking. If you use wood as your straight-edge (as in your picture), you run the risk of any natural warping or warping caused by the clamping affecting the readings. I use a 3-foot milled aluminum bubble level as my straight edge.

 

[Wayn23]

One approach to calibrating your inclinometer would be to buy (for later return) a high-end digital inclinometer and use that to create a 'reference' level surface (but this assumes, of course, that it is accurately calibrated).

That is not fair to companies who then get stuck with used items they can't sell as new.


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