Newbie Here Elevation help needed for 1.8m offset dish (Malta)

[Tim Bamber]

Hi everyone,

I'm in the process of setting up the dish in the attached photos.

View attachment 69282

I bought it second hand and only a few miles from where i live therefore I expected the elevation to be more or less accurate, however, the information I have found on the internet from many different sources tells me that the dish was elevated much higher than it should be.

I have the base set up accurately...
View attachment 69283

My main goal is to view 27.5W Intelsat but I ideally want to get it setup properly to make use of the motorised capability.

I have calculated the offset angle of the dish to be 24.6 based on the help provided here: -http://www.satsig.net/pointing/finding-dish-offset-angle.htm

and I know that my dish elevation is supposed to be 29.4 based on my location etc from dish pointer.com

What i need to know is as I'm no mathematical genius, if someone would be so kind, is what angle should the face of the dish be? I can accurately measure this angle with the inclinometer on the dish frame shown here..



What I'm not so confident at is using the angle here..


especially when it comes to calculating the declination. Any assistance would be very much appreciated, particularly from anyone who can identify the make or who has a similar dish to this.

Thank you.

Timinuk

 

[Trust]

If your caculation is right , the frontline of the dish has to lean 29.4 minus 24.6 º = 4.8º backwarts .
So try to find a straith piece of wood / metal thats long to reach the top and bottum from your dish and put the inclinometer there .
Once adjusted and checked the right elevation , messure at the back and notice that value as a reference for the future .
To identify the dish it would be helpfull to see the complete backside .

 

[Tim Bamber]

Thanks for the reply. I attach a few more pictures.
View attachment 69310




What you say is exactly what I had been guided to from the research I had done. My only concern is that this would seem to be now a too shallow angle for a location this far south -
Latitude: 35.9054°
Longitude: 14.4912°
Whereas before I was concerned the original set angle was too steep! Perhaps my calculation of the offset of the dish is incorrect, I'm not sure.

Also, as I have fixed the base to the 1 ton concrete pad(!) based on the S direction the former owner has the dish at, to lower the angle to 85.2 would mean the dish hitting the leg as seen on the second photo, which makes me think some calculation or other is wrong.

I had to replace the elevation adjustment threaded rod as well because the previous one was not long enough to allow me a more vertical elevation. Confusion reigns in this household!

Thanks,

Timinuk

 

[archive10]

If your caculation is right , the frontline of the dish has to lean 29.4 minus 24.6 º = 4.8º backwarts .
To identify the dish it would be helpfull to see the complete backside .

From another discussion on this board I remember someone on Malta posting pics of a dish that looked just like this one.

The dish is a copy of a Channel Master 1.8 made locally in Malta. He said a few had been made, and was done using a real CM180 as a stencil, then making a mold, and then producing the dishes in that mold. Hence no support ribbing in the back, but a rather large metal frame to provide bracing. It supposedly worked rather well.

That means that it has same characterestics as the CM180.

 

[archive10]

Thanks for the reply. I attach a few more pictures.
What you say is exactly what I had been guided to from the research I had done. My only concern is that this would seem to be now a too shallow angle for a location this far south -
Latitude: 35.9054°
Longitude: 14.4912°
Whereas before I was concerned the original set angle was too steep! Perhaps my calculation of the offset of the dish is incorrect, I'm not sure.

Also, as I have fixed the base to the 1 ton concrete pad(!) based on the S direction the former owner has the dish at, to lower the angle to 85.2 would mean the dish hitting the leg as seen on the second photo, which makes me think some calculation or other is wrong.

I had to replace the elevation adjustment threaded rod as well because the previous one was not long enough to allow me a more vertical elevation. Confusion reigns in this household!

I have a suggestion for the conundrum:

As the dish is on a polar mount, you have to remember that the dish need to point due south (spot on!) when centered. This means point at 14.5E, based on your location. Here, the dish should have an elevation of 48.3 degrees, which yields 25 degrees or more of elevation on a CM.

Once the dish is moved by the motor on the polar axis to point at 27.5W, the dish is tilted westward, and you get the proper elevation of a couple of degrees on your dish (and remember the dish face also looks rotated).

So to use your installation properly, set up the polar mount correctly (center the thing, point due south, get fix on 14.E, move dish east and west and align east and west sats etc.etc.etc. There are guides elsewhere on this forum!)

 

[Tim Bamber]

Thank you st1. I will try again and feedback on here!

 

[Gerry55]

Latitude Axis Zenith Declination

Latitude Axis Zenith Declination

5 5.13 5.8 0.67

10 10.26 11.7 1.44

15 15.37 17.6 2.23

20 20.47 23.4 2.93

25 25.57 29.2 3.63

26 26.58 30.3 3.72

27 27.59 31.5 3.91

28 28.61 32.6 3.99

29 29.62 33.8 4.18

30 30.63 34.9 4.27

31 31.64 36.11 4.47

32 32.66 37.25 4.59

33 33.67 38.38 4.71

34 34.67 39.52 4.85

35 35.68 40.65 4.97

36 36.69 41.78 5.09

37 37.69 42.9 5.21

38 38.7 44.03 5.33

39 39.7 45.15 5.45

40 40.71 46.27 5.56

41 41.71 47.38 5.67

42 42.72 48.5 5.78

43 43.72 49.61 5.89

44 44.72 50.72 6

45 45.71 51.82 6.11

46 46.71 53.92 7.21

47 47.7 54.02 6.32

48 48.7 55.12 6.42

49 49.7 56.21 6.51

50 50.69 57.31 6.62 London

55 55.66 62.72 7.06

60 60.59 68.06 7.47

65 65.52 73.32 7.8

70 70.43 78.52 8.09

75 75.33 83.64 8.31

80 80.22 88.69 8.47
5 5.13 5.8 0.67

10 10.26 11.7 1.44

15 15.37 17.6 2.23

20 20.47 23.4 2.93

25 25.57 29.2 3.63

26 26.58 30.3 3.72

27 27.59 31.5 3.91

28 28.61 32.6 3.99

29 29.62 33.8 4.18

30 30.63 34.9 4.27

31 31.64 36.11 4.47

32 32.66 37.25 4.59

33 33.67 38.38 4.71

34 34.67 39.52 4.85

35 35.68 40.65 4.97

36 36.69 41.78 5.09

37 37.69 42.9 5.21

38 38.7 44.03 5.33

39 39.7 45.15 5.45

40 40.71 46.27 5.56

41 41.71 47.38 5.67

42 42.72 48.5 5.78

43 43.72 49.61 5.89

44 44.72 50.72 6

45 45.71 51.82 6.11

46 46.71 53.92 7.21

47 47.7 54.02 6.32

48 48.7 55.12 6.42

49 49.7 56.21 6.51

50 50.69 57.31 6.62 London

55 55.66 62.72 7.06

60 60.59 68.06 7.47

65 65.52 73.32 7.8

70 70.43 78.52 8.09

75 75.33 83.64 8.31

80 80.22 88.69 8.47

 

[Trust]

Thanks for the reply. I attach a few more pictures.
View attachment 69310

View attachment 69312


What you say is exactly what I had been guided to from the research I had done. My only concern is that this would seem to be now a too shallow angle for a location this far south -
Latitude: 35.9054°
Longitude: 14.4912°
Whereas before I was concerned the original set angle was too steep! Perhaps my calculation of the offset of the dish is incorrect, I'm not sure.

Also, as I have fixed the base to the 1 ton concrete pad(!) based on the S direction the former owner has the dish at, to lower the angle to 85.2 would mean the dish hitting the leg as seen on the second photo, which makes me think some calculation or other is wrong.

I had to replace the elevation adjustment threaded rod as well because the previous one was not long enough to allow me a more vertical elevation. Confusion reigns in this household!

Thanks,

Timinuk

Looking at attach 2 , you can use the vertical ribs at the backside for elevation messurement .

 

[zorbua]

Hi, That's a Locally built dish and I believe if it's properly assembled very accurate, I have attached another similar built one though of 1.2 Dimension.
These images should give you a pretty good idea of it's installation. I have never myself personally come across one so I am not that familiar with it, but as I said if installed properly it will make a grand dish. This one is perfectly installed and tracks the arc perfectly.

 

[archive10]

Thank you st1. I will try again and feedback on here!

Just to be clear, setting up polar mounted dish of this size can be an extensive procedure (esp. if you haven't tried it before). The narrower beam-width requires a bit more precision than a 70cm dish on a DiSEqC motor.

But it is fully doable, you just need to be patient, and willing to fiddle and optimize.

Having a meter with NIT and/or SDT/PMT reading capabilities is optionally handy, as it will allow you to move the dish quickly between east and west sats to check aligment. But not a pre-requisite.

Good luck!

 

[Tim Bamber]

Latest news, thanks to all your help and advice, I have got reception 1st on 13.0E which was closest to my due S position and also tracked successfully to 28.2E which was as far as I wanted to go in that direction. Now when I try to go W, as far as I can successfully receive is 5.0W, anything further than that and I can get any reception. Is this anything to do with the declination? I don't think so as I can track successfully E but I would be grateful for advice. Perhaps 27.5W is out of my reach with a 1.8M dish from my location but I would expect to get some sort of a lock beyond 5.0W.

As always, any tips would be greatly appreciated. I'm getting there slowly with your help!

Thanks all

 

[zorbua]

First of all I wanted to point out to you that the Actuator motor should be the other way round (according to your pictures above the hole for water drainage is above rather than below) and that's the first thing to remedy. Look at the images above which I uploaded previously.
Now getting to your queries, the Polar mount should be setted up carefully after having the elevation perfectly set. Look at the two settings of the uploaded image. If you eventually manage to set up correctly you can easily track from 30W - 68E.

 

[Tim Bamber]

Thanks for the reply zorbua, there is no drain hole on the actuator I have......

 

[zorbua]

Thanks for the reply zorbua, there is no drain hole on the actuator I have......

There should be one under the Head bolt. Yours is a SuperJack. (taht il ras tal Bolt biex l-ilma johrog minna).

 

[wium78]

Your due South position could be slightly out.Also,check that the mounting pole is 100% vertical.

 

[zorbua]

Pity is that sometimes one doesn't hear whats or how things went, but I guess that's life sometimes!

 

[Lazarus]

You could always pop round and do a recce for us .......................... ;)

 

[zorbua]

You could always pop round and do a recce for us .......................... ;)

No much Tivu, this chap already posted the same thread in another Forum and I answered it as best as I could. I even send him
a pm in Maltese in that Forum but no response.

 

[PaulR]

That's a shame. But at least you have our thanks!

 

[Archived-1]

Pity is that sometimes one doesn't hear whats or how things went, but I guess that's life sometimes!

Well the thread did help one member

Hi, sorry had to pick the wife up, a 1.8 dish is harder to setup, are you using an inclinometer ?, I would suggest having a read through this thread to give you an idea,
http://www.satellites.co.uk/forums/threads/elevation-help-needed-for-1-8m-offset-dish-malta.163061/
You could also start your own thread here.
http://www.satellites.co.uk/forums/dish-setup-single-sat-multi-sat-motorised.385/
Good luck

I Finally managed to complete this today.
I do not think that I fully appreciated the precision involved and required. I guess I sort of hoped to move the dish around in the general direction and get lucky but that ended up being a wasted day.
With the help of - http://www.dishpointer.com/ - I was able to obtain the correct Elevation for the satellite from my location. I then downloaded an app called ' Level ' from the app store to set the inclination correctly. Once the correct inclination was set I was then able to locate the Sat with relative ease.
Thanks again for your help