Re: [amsat-bb] Question regarding gain of Dish Antennas with different feeds

[Al Lawler <alawler@xxxxxxxxxxxxx>]

  John,

  I think that just figures into the 'efficiency' of the
  antenna.  Assume that the perfet dish of any given size 
  is is capable of "n" db of gain.

  The quality of the feed (I.e. how completely you illuminate
  the dish without overilluminating it)   determines how close 
  to the maximum efficiency you actually get.  (A higher gain 
  helix would illuminate less dish area, resulting in a smaller 
  overall effective antenna area, so it's essentially a zero-sum
  game.)

  -al
  WB1BQE


John Wilcox wrote:
> 
> This is a question I had, as well. I am using a helical for the feed of a
> Primestar 1.0m dish. The 5 turn helix has 11(?) dB gain. Is this added to
> the 25 dBi gain of the dish? There must be some addittive value over just
> putting a dipole at the focus...
> 
> ----- Original Message -----
> From: <W1BFN@aol.com>
> To: <amsat-bb@AMSAT.Org>
> 
> > Question: Will the Gain of the patch antenna increase the overall gain of
> the
> > dish I put it in, either directly by virtue of its stated gain, or
> indirectly
> 
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