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<blockquote data-quote="Old Fred" data-source="post: 24213">Find the approximate focal point by aiming the dish at the sun and holding a piece of white card in front of it. (This doesn't work too well with a black dish!)Now fix your LNB so that the entrance to the horn is at the focal point. Make your bracket adjustable because this is only approximate.The LNB horn should match the f/d ratio of your dish (don't ask - I just read it in a book!) otherwise it might not be collecting signal from the full area of your dish and, if you move it further away, it's no longer at the focal point. Or the opposite can occur where the LNB horn is collecting signal from too wide an area so it collects heat readiation from anything behind the dish. It's &quot;looking around the edge&quot; of the dish, in other words.Normally a dish is supplied with a matching feedhorn by the manufacturers. Anything else is likely to be inferior.The &quot;twist&quot; (&quot;skew&quot;) position has to be optimised, too, for best &quot;signal quality&quot;.Fred</blockquote>

[QUOTE="Old Fred, post: 24213"] Find the approximate focal point by aiming the dish at the sun and holding a piece of white card in front of it. (This doesn't work too well with a black dish!) Now fix your LNB so that the entrance to the horn is at the focal point. Make your bracket adjustable because this is only approximate. The LNB horn should match the f/d ratio of your dish (don't ask - I just read it in a book!) otherwise it might not be collecting signal from the full area of your dish and, if you move it further away, it's no longer at the focal point. Or the opposite can occur where the LNB horn is collecting signal from too wide an area so it collects heat readiation from anything behind the dish. It's "looking around the edge" of the dish, in other words. Normally a dish is supplied with a matching feedhorn by the manufacturers. Anything else is likely to be inferior. The "twist" ("skew") position has to be optimised, too, for best "signal quality". Fred [/QUOTE]

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