[amsat-bb] Helix feeds revisited

["Howard Long" <howard@xxxxxxxxxxxxxx>]

Folks

I re-modelled the G3RUH helix feed from scratch with a far more accurate
representation than my first attempt and came up with some slightly
different results.

 Turns  Gain (dBi) F/B (dB)  3dB Beamwidth  10dB Beamwidth
  2.25      9.6      13.3        61.2            116
  2.75     10.0      14.8        57.2            107
  3.25     10.6      14.6        52.8             95
  3.75     11.0      13.2        50.8             88
  4.25     11.2      13.3        49.7             85
  4.75     11.4      15.0        48.1             81
  5.25     11.8      15.7        46.0             78
  5.75     12.0      14.2        44.3             74
  6.25     12.2      13.8        43.3             71
  6.75     12.5      15.4        42.1             69
  7.25     12.7      16.8        40.6             66
  7.75     12.9      15.5        39.4             64

Beamwidths are in degrees.

73 Howard G6LVB

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