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Offset, why?
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<blockquote data-quote="Channel Hopper" data-source="post: 682" data-attributes="member: 175144"><p>On most commercial offset dishes the minimum diameter is the one stated, ie a 1.8 m will have the longer diameter of 2m which improves gain</p><p></p><p>Strictly speaking the feed of a prime focus dish will have a known f/d ratio and is matched with a manufacturers feed to maximise the gain and noise characteristics (and this is the same with the larger offset units - we supply up to 3.8m in offset form). Domestic offset dishes leave the end user to use a standard universal LNB with an unknown efficiency and perfoemance curve.</p><p></p><p>The other difference (ignoring the fact the feed is in front of the dish on a primefocus - this should not affect to a great degree) is the illumiation of the feed by outside effects. The prime focus dish is likley to be affected by some noise generated from the ground behind the dish if this is excessive, the offset having the feed looking up into the air and so seeing effects from the sky.</p></blockquote><p></p>
[QUOTE="Channel Hopper, post: 682, member: 175144"] On most commercial offset dishes the minimum diameter is the one stated, ie a 1.8 m will have the longer diameter of 2m which improves gain Strictly speaking the feed of a prime focus dish will have a known f/d ratio and is matched with a manufacturers feed to maximise the gain and noise characteristics (and this is the same with the larger offset units - we supply up to 3.8m in offset form). Domestic offset dishes leave the end user to use a standard universal LNB with an unknown efficiency and perfoemance curve. The other difference (ignoring the fact the feed is in front of the dish on a primefocus - this should not affect to a great degree) is the illumiation of the feed by outside effects. The prime focus dish is likley to be affected by some noise generated from the ground behind the dish if this is excessive, the offset having the feed looking up into the air and so seeing effects from the sky. [/QUOTE]
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Offset, why?
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