HELIX antenna FOR 2.4 GHZ UPLINK.

  • DIY's third Helix antenna was tested tonight and can work in SSB mode.And make QSO with PA1EW and PA3FYM.PA3FYM gives the signal report of s58.Receive using websdr, websdr currently has many delays and pauses.Also used IS0GRB websdr page, almost the same effect...Can anyone give more options for websdr?

    30 N. Length 92 cm

  • Hi Zhaofeng,


    Many thanks for the first QSO with you !. The IS0GRB websdr usually is working OK, so I assume that you might have local internet connection problems?.


    Nice helix that you are using now. But, perhaps there is some negative effect from the reflector not in the correct position (not 90 degrees angle) due to the weight of the long antenna. Please see the picture with a better solution how to construct the antenna/reflector mounting. See you soon back on QO-100


    73 s Ed PA1EW JO20UT

  • The antenna is not perpendicular to the tomato wire due to the improper replacement of the supporting material. I will fix it next week. If you use conductive material inside the helix, does it really affect the emission?

    At first, I used the carbon fiber tube as the support, and it began to get hot during high-power launch. After replacing the fiberglass tube, I found that the carbonized part of the plate during laser cutting during launch had a flame. It didn't work until I cleaned out all the internal conductive parts

    If used for receiving, I don't find any effect of conductive material inside the antenna. From the return loss, there is almost no difference. Right

  • BG0AUB Hello Zhaofeng, the use of a conductive support, diameter < 0.1 wavelenght, INSIDE a helix is perfectly OK!. SWR may change a little bit, but will be good. The helix construction shown by G4SDG on the 1st picture in the other thread "DIY Helix for 2.4 GHz uplink . Can I use 5mm copper tubing?" is a very good example how to do it, in my opinion. See also the examples and explanation from G8AWB in the same thread.

    You can use 10mm x 10mm square aluminum support tube which is light and strong.

    Use only a few (nylon/teflon) vertical supports, exactly as seen in that picture and do not use any other support fixing the helix wires. This is to avoid degradation of the beam pattern.

    I have written a "How-To-Construct a helix" document with a lot of practical information, that I can provide to you (and any other interested)!.


    You probably know that this type of helix has less gain than a small offset dish with a small helix- or patch feed. My 1.0m wide offset dish with dualband helix/LNB-feed is putting out a very nice signal to QO-100 , but smaller dishes working equally good.


    73 s Ed PA1EW


  • So how do you explain the heating of the carbon fiber tube support during launch? The diameter of the carbon tube is 12mm, and my emission power is 20w or more. The carbon tube is in the center of the spiral coil. Heating is evident near the reflector feed. In addition, the carbon tube may not have communicated with the reflector

  • From your pictures it seems that the carbon-fibre support is not in the centre of the helix. When not connected to the reflector, this may be the reason for the heating.

    You do not have to be afraid that an aluminum support in the centre of the helix will heat-up!


    Good luck with your experiments!


    73 2 Ed PA1EW

  • Thank you for your reply.I will try to conductive support and reliable reflector conduction, observe whether it will warm.

    "How-to - the Construct a helix" document where I can find it?I will carefully study him

  • Zhaofeng, it is a PDF-document that I can provide to you via e-mail. I have to find a way to put it online somehow...

    I will first add some more information about the the helix-type you are building.


    73 s Ed


    BG0AUB My updated document is sent by e-mail to you


  • Coil is yellow in glass fiber board, used to keep the spiral shape

    In order to make up for a lack of overall rigidity, fixed with a carbon fiber tube in the middle.

    Now I have the carbon fiber tube and reflector and reliable connection (conductive carbon fiber tube)


    Using the computer design parameters

  • This article I published around 20 years ago.


    Don't have it anymore (because the server -at that time- doesn't exist anymore) but somebody saved it for later use.

    Still is a reference for me.
    My first wifi antenna was based on your article.

    Salomão Fresco

    Callsign: CT2IRJ

    GRID Locator: IM59re -- CQ Zone 14 / ITU Zone 37

    QTH: Fazendas de Almeirim, Portugal

  • Perhaps I will write it down, but it has to do with the ETSI standard concerning what we now call WiFi (then called 'radiolan') and how 'we' obtained +20 dBm output/EIRP (whatever) power (at 2.4 GHz) (draft recommendations were far less output)

  • PA1EW I read your article carefully, there are a lot of harvest.

    Do use five minutes late out houses (window) to do the uplink test.The helix antenna works well.I think he has 16 to 18 db gain.Thank you for all the people who help me...New idea is: may challenge without DISC antenna, the use of LNB with what other antenna QO100. Personally, I think this is very difficult, because 60 cm DISC in 10 g gain about 35 db