MULTI LNB SETUP

[srinivas33]

RE: UNABLE TO CATCH INSAT-4A

Off axis signal causes aberration, and also the focal distance slightly varies for side LNBF, Here is the simulation made using this Off axis parabolic reflection simulator

off-axis parabolic reflection on Scratch

observe these the focus of off axis rays is not same as the center LNBF, it is somewhat less or near to the dish,

so you adjust your second LNBF somewhat lower or push nearer to the dish as shown in simulation. Once try it and see.

Reference:
http://scipp.ucsc.edu/~haber/ph5B/parabolic09.pdf
off-axis parabolic reflection on Scratch

 

[riteish]

RE: UNABLE TO CATCH INSAT-4A

@srinivas33 thanks for explanation, here are the more ss of my second lnb for asiasat-3s @105.5 but as i said earlier signal quality is not stable sometime it shows up to 65% or most of time it stays at 0% so please guide where i may wrong & can any one confirm the accurate & actual practical distance between center lnb insat-4a@83 and asiasat-3s lnb @105.5, as i have seen on one of the post he has given some degree subtraction and multification calculation like 105.5-83〓A, then A X 1.3 〓 B and this B indicate distance between two lnb but in my case i have also tried this but same is not happening then by practical i found this spot by just holding lnb in hand for several miniute and like this i have fitted as below in ss

 

[giri photog]

RE: UNABLE TO CATCH INSAT-4A

i have doubt on your skew setting of lnb.....can you check once again

 

[giri photog]

RE: UNABLE TO CATCH INSAT-4A

rithesh will you plz post a longer view photo of dish. i think the lnb position is wrong. i installed this dish twice in maharashtra so i can guide you on regarding this

 

[riteish]

Re: UNABLE TO CATCH INSAT-4A

Just a moment before I received the ku band freq 12720/V/30000 with siganal quality 70% and is stable but when I just replaced connector to c band position the same thing happening it shows some time up to 19%-28%-80% and 0%

 

[giri photog]

RE: UNABLE TO CATCH INSAT-4A

plz post a distant view of dish......so that i can observe the skew position with respect to dish angle. seems your skew is wrong

 

[dr30ma]

RE: UNABLE TO CATCH INSAT-4A

105.5-83=22.5
1*=1.7 cm
From middle of lnb to middle of 2nd lnb.
22.5x1.7=38.25 cm.

 

[giri photog]

RE: UNABLE TO CATCH INSAT-4A

s this is the correct skew .......note down the where the lnb labeling facing

change the skew then it will disturb your current signal strength then adjust the dish vertically and horizontally again and you will get the position where the stable signal locks stb.

good luck and happy hunting

 

[riteish]

RE: UNABLE TO CATCH INSAT-4A

plz post a distant view of dish......so that i can observe the skew position with respect to dish angle. seems your skew is wrong

thanks for your reply sir giri photog are the one of the member from whom i have inspired to do this setup, actually when i visited to this forum i have seen various member multilnb setup and you are the one of them.

 

[riteish]

RE: UNABLE TO CATCH INSAT-4A

105.5-83=22.5
1*=1.7 cm
From middle of lnb to middle of 2nd lnb.
22.5x1.7=38.25 cm.

[/quote

as per your this pic and above explanation distance between asiasat3s and insat 4a lnb is 38.5cm. i have also tried at this distance but could not get any signal but i am receiving siganal at just 20cm.from insat4a lnb see below pic