LNBF and dish Focal length

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ali257t

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Hi, My LNB is integrated with feedhorn. (its a ku-band LNBF)
This LNBF is installed on a holder (adjustble plastic ring) and this holder is connected to the dish by tripod.
The length of LNBF is about 15cm and its contain some parts, that are:
A circular muzzle in the front, a tube in the middle -or neck- (that is 7cm) and a square part in the back.
My dish focal length is 53cm and holder is matched on focal length when it is assembled.
Which part of this LNBF should be mount on the holder to save focal length? Frontal part and or middle part?
If your answer is middle part, dish to back of LNBF distance will be less than 53cm!
 
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Adjust it for best signal.:)
 
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ali257t

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thanks, but i want to know, what is correct assembling?
 
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Can you post photos ....generally it will be in the middle of the tube(wave guide) between the (feed) horn at the front and the (LN) Block at the back -
 
rolfw

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As Robbo said, you adjust it until you get the best signal quality.
 
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ali257t said:
Hi, My LNB is integrated with feedhorn. (its a ku-band LNBF)
This LNBF is installed on a holder (adjustable plastic ring) and this holder is connected to the dish by tripod.
The length of LNBF is about 15cm and its contain some parts, that are:
A circular muzzle in the front, a tube in the middle -or neck- (that is 7cm) and a square part in the back.
My dish focal length is 53cm and holder is matched on focal length when it is assembled.
Which part of this LNBF should be mount on the holder to save focal length? Frontal part and or middle part?
If your answer is middle part, dish to back of LNBF distance will be less than 53cm!
Click to expand...


Those dimensions match a C120 Channel Master feedhorn & MTI LNB 'made up'. If that is the case it's a C120 not an LNBf. Is there a 50mm flange with small bolts/screws connecting the feed horn(tube-muzzle) to the (LN) block at the back?

Anyway... the focal length should be closer than 53cm to the 'face'... the focal length is 'inside' the LNB's feed horn not at the face ... it's about 30-40mm in if you have got a C120.... or 49-50cm from the dish face to the face of the LNB's feed horn... then as recommended... fine adjust for best signal.

Again... a picture would help.
 
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