Declination Angle

[samoloko]

Chris
did you tuned up properly your gibi 1.5
can you please give me a digital angle meter reading when you place It on a back support profile and point dish to 28.2

 

[Archive-8]

Chris
did you tuned up properly your gibi 1.5
can you please give me a digital angle meter reading when you place It on a back support profile and point dish to 28.2

This is the height of 28.2E :-


Gibertini 1.2&1.5 has the same offset off 21.5°

So 24.90° - 21.5° = 3.6°

Is it a fixed dish or motorised?

 

[samoloko]

Chris
thank you for reply
but I like to have a practical value of angle, when you place digital angle meter back to back with back feed suport profile of gibi 1.5 - somewhere around conjuction with lower lnb support arm when you tuned at 28.2

 

[Archive-8]

Chris
thank you for reply
but I like to have a practical value of angle, when you place digital angle meter back to back with back feed suport profile of gibi 1.5 - somewhere around conjuction with lower lnb support arm

I have done the photo for you, but my dish is not 100% right. Still lots to play with and adjust.

 

[samoloko]

you are great
appreciate very much
thank you very much
where did you place digital angle meter - Is It on dish
can you measure again but placed at the rectangular back profile at the lower back of the dish around junction with lower lnb support arm
but please only when you got time
cheers

 

[Archive-8]

you are great
appreciate very much
thank you very much
where did you place digital angle meter - Is It on dish
can you measure again but placed at the rectangular back profile at the lower back of the dish around junction with lower lnb support arm
but please only when you got time
cheers

The 1.2 has a back panel like you have discussed, the 1.5 hasn't. So can you please post a photo of where you want the reading?

 

[samoloko]

thank you Chris
please see attachement
don't forget that dish have to be pointed to 28.2 E
cheers

 

[Archive-8]

thank you Chris
please see attachement
don't forget that dish have to be pointed to 28.2 E
cheers

That's is where I took the photo from. :-)


On 28.2°E

 

[samoloko]

It Is so close that I misplaced dish with back support profile
thank you very much for your support
cheers

 

[RimaNTSS]

Guys! I do not know whether red line is parallel to green line. Perhaps not, as I see from calculated antenna leaning 3,6* and measured 6,9* quiet a difference. Of course all those angles greatly depend on position of the LNB... I mean if it's Phase center is located in F1 or F2.
@Chris1979 could you measure leaning of the face of your dish along green line?

 

[Archive-8]

This is the best I can do at the moment. Will try and measure it properly later on.

 

[RimaNTSS]

This is the best I can do at the moment. Will try and measure it properly later on.

Much better now. Only, instead of holding protractor on the edge of the antenna you better put some straigth plank from top to the bottom of the antenna and then attach protractor to this plank. So, if antenna has 21,5* offset angle and it is pointed to satellite which has elevation 24,9*, than leaning of the face of the dish should be, as you rightly pointed earlier 3,6*. And if you measured leaning 3,1* than you have 0,5* difference and that might automatically mean that LNB's Phase center is not co-located with Focal point of the dish. Another causes of the problem could be that antenna maybe has different offset angle or you have measured leaning angle not precisely or antenna is warped, or protractor is not properly calibrated.... Which option do you prefer? There could be also combination of several problems. And final result - antenna-system is not performing as good as it could perform.

 

[Archive-8]

Just managed to find a bit of wood long enough.


On 28.2E.

 

[RimaNTSS]

Not good. Did you make string test of your antenna?

 

[Archive-8]

Not good. Did you make string test of your antenna?

Not done anything like that yet, not had a real chance.

 

[RimaNTSS]

That, actually, should be first thing that should be done before installing, tuning, testing and making conclusions about performance.

 

[Archive-8]

That, actually, should be first thing that should be done before installing, tuning, testing and making conclusions about performance.

How do you do the string test? Please.

 

[RimaNTSS]

How do you do the string test?

Couple of pictures should be enough. There should not be any gap between strings. Even 1mm is not good.

 

[Archive-8]

Couple of pictures should be enough. There should not be any gap between strings. Even 1mm is not good.

Thank you for that. :-) I will have to pick up some string in the next day or so.

 

[RimaNTSS]

I will have to pick up some string

Simple thread or fishing line would also work. Make sure strings are touching edges of the working area of the dish not physical edges of the dish.