1240MHz/1280MHz DIY Helix Antenna

Just finished with my helix antenna, designed for 1240MHz.
Used the helix calculator from http://jcoppens.com/ant/helix/calc.en.php.
Parameters were 1240MHz, 8 turns, 0.23 wavelengths.

My internal helix diameter is roughly 80mm with a coil spacing of 55.5mm. Wire diameter is 3.5mm/10mm².
Reflector size is 250mmx250mm. Center support is made from 6mm Balsa, soaked with epoxy resin.
For matching the IBCrazy wave trap method is used. Trap size is 30mmx15mm. See also http://www.rcgroups.com/forums/showthread.php?t=1377791

 

2 thoughts on “1240MHz/1280MHz DIY Helix Antenna

  1. Hello , is there any disadvantage major, if i use 2.5mm instead of 3.5 or 4.8mm copper diameter?

    • Wire diameter is not critical. Keep in mind that lower the frequency is, larger the wire diameter should be.

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