New Lnb changer

[Trust]

Sorry Trust1, I feel I am no longer able to help on this topic

@ Milamber , I'm sorry to hear that , someone else could check that , but please consider

 

[Captain Jack]

My neighbours, by now, think I've completely lost my mind measuring the great big monster every few days....

Measurements at widest point. I'll let you make up your own mind over where the WAD is.

 

[Lazarus]

Phew. I started reading your Post and my jaw dropped. Thankfully I'm not one ever to take anything out of context.

 

[Captain Jack]

It's what I was going for, G ;)

 

[PaulR]

Judging from the shadow in the first photograph the roll-off is at least 1.5cm. The second photo implies that it's more like 2cm. The second photo also shows that the outer edge to outer edge width is 184cm so the reflective area that's part of the parabola is 180cm to 181cm.

BTW, this talk of reflective area assumes that the real reflective surface, that's just underneath the outer gel coat, actually extends all the way to the edge. We would assume so but who's to say that there aren't some which don't? Or is that another kettle of fish...

 

[Captain Jack]

If only we could convince someone to hack into their Laminas to find out where the reflective material extends to...

 

[Trust]

If only we could convince someone to hack into their Laminas to find out where the reflective material extends to...

No need to destroy such nice dish .
Maybe someone has a inductive approach switch , such switch reacts at the metal inside the dish by lighting up red .
First I tried it with a Wall pipe locator but they are to sensitive , maybe with a distance holder between the sensor and the dish , it works better .

Made a test at my CM , at some edges it reacts immediate , but I found also a point with the first reaction at 20 mm from the edge .

 

[Captain Jack]

Interesting idea. But do we really need to worry about such minute details? This could be a never ending saga otherwise

 

[Trust]

Interesting idea. But do we really need to worry about such minute details? This could be a never ending saga otherwise

Remember , You asked for it

If only we could convince someone to hack into their Laminas to find out where the reflective material extends to...

 

[Captain Jack]

Yes, yes

I just want my LNB rotator...

 

[Trust]

Friday I will go on with this Parabola setup , it allows the use of the original sidearms without bending them .
Just have to to some drilling and make the side-arm attachment at beam-side .
Strenghtening rods/pipes are allready made .

 

[Archive4]

Interesting idea. But do we really need to worry about such minute details? This could be a never ending saga otherwise

What you need is Falkor!



No problems then!

 

[Trust]

I'm not allowed to go to the shed , so did some research at the desk .
Found out that there is something wierd with that russian parabola calculator .
Changing the dept values from 1 to 1000 mm does not effect the calculated offset angle at all , that cant be right .
I found another parabola calculator at Parabola Calculator for Satellite Dish Antenna Design | Electronic Circuits
For offset dishes you have to choose the wifi version , there is a option for extra data if the deepest point of the dish is out of centre .
I know at Triax dishes that point is below centre , I dont know for the Laminas AS-1800 .
With that calculator by 1935 x 1800 x 170 (centre) the offset is 22.5º
Do I change the dept in that calculation , the offset angle change too .

 

[Captain Jack]

Interesting. Those calculations seems to match our measurements relatively well.

 

[a33]

Found out that there is something wierd with that russian parabola calculator .
Changing the dept values from 1 to 1000 mm does not effect the calculated offset angle at all , that cant be right .
I found another parabola calculator at Parabola Calculator for Satellite Dish Antenna Design | Electronic Circuits

No that is absolutely right in the russian calculator. Offsetangle is detemined by hight and width of the dish, and then the place of the 'cut' of the offset dish (relative to the apex of the PF mother dish) is determined bij one value: the depth at the geometrical center.

Beware! The wifi-offset calculator needs the depth at the deepest point, that is NOT the center of the dish.
I'm not sure why that should affect the calculated offset angle, though. Maybe because it has to 'average', because of measurement imperfections?

Greetz,
A33

 

[Trust]

No that is absolutely right in the russian calculator. Offsetangle is detemined by hight and width of the dish, and then the place of the 'cut' of the offset dish (relative to the apex of the PF mother dish) is determined bij one value: the depth at the geometrical center.

Beware! The wifi-offset calculator needs the depth at the deepest point, that is NOT the center of the dish. How do you know ? you dont find dat data in the specs .
I'm not sure why that should affect the calculated offset angle, though. Maybe because it has to 'average', because of measurement imperfections?


Greetz,
A33

With the deepest point out of the middle the reflecting surface has a different angle at aimingpoint "G" , so in my opinion it should effect at the offset angle .

 

[RimaNTSS]

Calm down folks, Laminas already changed offset angle of their product , now it is 21,5* (not 22,6 as previously stated)
I will not be surprised if they roll back to 22,6* offset but 1950mm vertical size. I still think that 1935mm is measured from very top point of the WAD to the point at the bottom where WAD connects to the feedarm, but, in reality WAD should be measured some 15mm lower.

 

[a33]

With the deepest point out of the middle the reflecting surface has a different angle at aimingpoint "G" , so in my opinion it should effect at the offset angle .

I don't understand what you are saying here, Wim.
G-spot (LNB aiming point) is not an important spot for the dish; it is important for the LNB, as it disects its opening angle to the dish, and spillover to eather side is minimized.
In the geometrics of the dish itself, it is of no meaning I believe.

The tangent line at the deepest point forms the offset-angle. A dish with the deepest point in the middle is a prime focus dish.

So what is it exactly you are saying? Sorry for not understanding you...

Greetz,
A33

 

[cardiff]

Effective Reflector Size / Dish front size (+1.5 all around)

Height dish = 1935 mm + 2 x15 = 1965 mm

Width dish = 1800 mm + 2 x 15 = 1830 mm

measurements made several times with the help of several people with me.

Rgds

Cardiff

 

[Archive4]

Weather permitting I will string the spare dish ( unmounted ) and take several pics showing the tape at various points. I'm not going to quote the dimensions, I'll leave it for you all to decide by yourselves!