5.8 GHz Helix Antenna

This is an example how one can hit the target on spot with a clean build even on 5.8GHz.

Antenna dimensions:

  • Design frequency 5800MHz
  • 8 turns
  • Wavelength 0.23
  • Internal diameter 17-17.5mm
  • Wire diameter 1mm
  • Coil spacing 11.8mm
  • Reflector 40mmx40mm
  • Wave Trap size 6.5mmx3.2mm
  • Wave Trap spacing from feed point 2mm
  • Feed point height 2.5mm (wire center), maintained over 1/4 turn

19 thoughts on “5.8 GHz Helix Antenna

  1. Michael,

    I´ve built your 8 turn 5.8ghz helical antenna. I don´t have the IBcrazy DIY SWR meter. I kinda wondered if I can verify /tune it using transmitter current draw. I have noticed that the DIY rubber ducky has a current draw of 120ma while the IBcrazy bluebeam has about 105ma draw. It looks like to me that the rubber ducky that comes with it has more SWR compared to IBcrazy bluebeam. Can I use this transmitter current draw to tune my newly built helical ?

    Thanks for you DIY projects. It´s very helpful.


    • You may try. Of course it will be not as good as a SWR meter but at least you can minimize the energy which will be dissipated in heat.

      • Michael,

        Thanks..Do you know if it´s going to be the minimum current to have good SWR or maximum current in the transmitter? I actually tried moving the rectangular tuning strip that you solder in the first quarter turn of the helical and it gave me the minimum current draw soldered directly to the feedpoint and if I move it far from the feed point it gives me high current. approx, 20-30ma difference.

        Any advice is greatly appreciated. I am using the Foxtech 5.8ghz transmitter.

        Thanks again.


        • No idea about the current, I have no 5.8 equipment.

          You may try first without the wave trap. Just try to archive minimum current by adjusting the distance between ground and wire in the first quarter turn after the feedpoint. Some people reported that this was already enough for proper tuning.

    • “Coil spacing 11.8mm” is this measured from center wire? Thanks!

      and the internal diameter is a bit larger than what I get from online calculator. What´s the trick here?

      • Spacing is measured center wire. Diameter is not critical, to wind the coil I took an object with an outer diameter close to what was needed.

  2. Michael,

    I have posted the same comment on another page. That comment should be on this page..Sorry.

    Hence I don´t have the DIY SWR meter of IBcrazy projects, kinda wondered if I can use the transmitter current draw to verify/tune this antenna? If so, for good SWR is it maximum current or minimum current draw?



    • For what you want to use RG174?
      When used to connect antenna and RX then keep it as short as possible. It has around 60dB/100ft @ 5.8GHz, way to much, but ok as long as cable is short.

    • I personally did no test because I have no 5.8GHz equipment. The antenna was tested by someone else and as far as I remember the result was sufficient with >3km.

  3. I am struggling with your design, coil spacing should be 11.8mm, but in your photo the first quarter turn to the one above it is less than 11mm.
    Can you elaborate how the turn spacing works (from the very first turn to the next)


    • The very first turn makes an capacitive element together with the ground plane. Hence the spacing of this turn has an influence on the resonance frequency, it´s a tuning element.
      Not sure where your 11.8mm coming from, if calculated then it´s a theoretical value. My 11m are tuned using a VNA. so it´s a practical result taking into account all build tolerances.

  4. Good day sir how did you compute for the size of your wave trap, reflector size, and the feed point height? Thank you.

Leave a Reply