Which Is Better Ku-Lnb For Prime Focus 360Cm Sold ( 4 Pieces ) Dish Shown Below

al_madhi

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Hi ppl I have a prime focus 360cm sold (4 pieces ) dish which has a narrow focal point which needs a large Ku-LNB with circular Rings that can collect more signal Rays towards the focal point therefore I have already these two Ku-LNBs shown below which one do you think is better for this large dish 380cm ? Please Advice so that I can install one of them awaiting your respond as soon as possible .

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A.M.AL-MADHI

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aceb

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The obvious answer would be try each one and test it yourself but seeing as the second image shows an Inverto designed for an offset dish I'd say you stand a better chance with whatever the first LNB is. Hard to see any detail as you've linked to an off sight image that won't click through. You might want to reupload a better quality photo to the server here because live links aren't permitted.
 

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al_madhi said:
which has a narrow focal point which needs a large Ku-LNB with circular Rings that can collect more signal Rays

That isn't how they work
 

Captain Jack

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CH, how do they work? I have very little clue about the wave-guiding process of a feedhorn and scalar rings...
 

al_madhi

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Channel Hopper said:
That isn't how they work

If it is not how they work Then How do they work ? But You did not answer the question which one of these LNBs I can use for the 360cm dish
 

ralphmagno

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ok the one on the bottom will not work good.it is for an offset dish and not prime focus.
the one on the top i can not see the picture good. if the lnb has a c120 flange and the feed has a c120 flange than it will work
you need to post more pictures of the top and side of the lnb on the top picture
ralph
 

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al_madhi said:
If it is not how they work Then How do they work ? But You did not answer the question which one of these LNBs I can use for the 360cm dish

Obviously first one should work better cuz it is for prime-focus dishes, however, depending on strength of signals you are fishing the second one could work as well. So, answer to your direct question (Which one of these LNBs I can use for the 360cm dish?) would be: You can use any of them, but results will be different. Anyway, 3,6 m antenna is very nice size, and it is dream of everybody from this forum (I think so).
 

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Captain Jack said:
CH, how do they work? I have very little clue about the wave-guiding process of a feedhorn and scalar rings...

A scalar feed is a 'compromise' device, improving the insertion loss by virtue of the radiation pattern of dual polarity reception from a parabolic source and offering at least two of the other factors below ;

1) optimising the transfer of wanted signal when the actual physical characteristics don't focus the signal to the phase centre
2) allowing a reasonable rejection of unwanted or spurious signal away from the phase centre
3) holding the waveguide and electronics to the focal point of the dish
4) withstanding outside physical elements - water, and heat, other outside elements from entering the waveguide and electronics.

For the physics required to build something that's 'the best' in all situations, impossible, but the attached article from 1999 does about the best in the majority of applications. Take note of the diagram (7) and the dimensions given which hold up well for many microwave frequencies.



I've mentioned scalar/choke parameters info before on the site. I'll have a look to see if it's around
 

al_madhi

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ralphmagno said:
ok the one on the bottom will not work good.it is for an offset dish and not prime focus.
the one on the top i can not see the picture good. if the lnb has a c120 flange and the feed has a c120 flange than it will work
you need to post more pictures of the top and side of the lnb on the top picture
ralph
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The LNB is STARGOLD FUJI - a universal Prime Focus Twin LNB it has a c125 flange similar to this one shown below

View attachment 44828
 

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al_madhi said:
---------------------------------------------------------------------------------------------------------------------------
The LNB is STARGOLD FUJI - a universal Prime Focud Twin LNB it has a c125 flange

Unless it is something uniquely destined for the Saudi region, there is nothing in the world that has a C125 flange.
 

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hello,
ok we need more pictures. the lnb you want to use and number. this looks like a c band and not a ku band feed horn.it is in 2 pieces instead of 1 piece. the this will not support 2 lnbs just one.
we need to see the c120 flange of the lnb.
ps there is no c125 you must be new at this.will look for more pictures.
ralph
 

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hello again,
the lnb fuji sg920 is what you have .it has a feed horn built in and it will not hook up to the prive focus feed horn you have.
you have to eather affix the lnb in place of the feed horn or get a lnb with a c120 flange and connect it.
it will not be easy unless the prime focus has other attachments to use what you have.
ralph
 

al_madhi

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ralphmagno said:
hello,
ok we need more pictures. the lnb you want to use and number. this looks like a c band and not a ku band feed horn.it is in 2 pieces instead of 1 piece. the this will not support 2 lnbs just one.
we need to see the c120 flange of the lnb.
ps there is no c125 you must be new at this.will look for more pictures.
ralph
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Can you show me what is ( c125 flange ) looks like show me a picture to see View attachment 44829
in the piture I attach isn't that the c125 flange you are talking about which is similar to the one on the STARGOLD FUJI SG-920

Please comment and advice
 

al_madhi

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View attachment 44830
ralphmagno said:
hello again,
the lnb fuji sg920 is what you have .it has a feed horn built in and it will not hook up to the prive focus feed horn you have.
you have to eather affix the lnb in place of the feed horn or get a lnb with a c120 flange and connect it.
it will not be easy unless the prime focus has other attachments to use what you have.
ralph
------------------------------------------------------------------------------------------------
I attached to you above a picture of my LNB STAR PORT SP-T20 PLUS with Circular Rings Can I use it for my dish 360cm if not what kind of Ku-band LNB do you recommend to use for my prime focus 360cm dish . Please Advice and elaporate on your comments
 

ralphmagno

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hello, it looks good but you need to see how it will attach to the mounting arms of the dish. what are you trying to receive?
what satellite?
Ralph
 

al_madhi

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ralphmagno said:
hello, it looks good but you need to see how it will attach to the mounting arms of the dish. what are you trying to receive?
what satellite?
Ralph
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Thanks Ralph for your help
It is already attached to the mounting arms no problem with that and regarding your question what satellite am I trying , I can receive 40 satellites which are receivable over Saudi Arabia if I want My Dish ia a motorized H-H paraclips from 22 deg west up to 105.5 deg east , the reason I am asking is to find the best possible LNB that can increase reception for satellites located in off- the foot-print areas which called in the fringe areas That ia all

Best Regards

A.M.AL-MADHI
 
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