Question with regards to NRF24 antenna folding

  • Hey guys!, 👋

    Newbie here and this forum has helped me out a lot figuring out several issues I have had with both my sensors.

    I have an NRF24L01 with antenna and another one without antenna; Does anyone knows why when the antenna is straight the connection dies, yet when it was "folded" the connection works?.

    I am actually trying to figure out why does this happens and how to "revert it", as in when the antenna is folded there is no connection and when its straight there is connection (I am also more than happy to have connection either if its folded or not btw but that doesnt seem to be the case).

    Any thoughts?

  • Mod

    Welcome @naruse 🙂

    Could you post photos of the two antenna versions?

  • Absolutely!

    The antennas

    For some reason when I have it folded 90deg (the one on the right) and I touch it I get the signal working, but when I dont, its random. I will try next the double capacitor method that I read here in this forum, but wanted to know if anyone has any insight about the antenna being folded or not

  • @naruse There is a thin co-ax cable in the antenna that folds, maybe it is damaged and contact is only made in the folded position and not when straightened out. Try another antenna if possible.

    Also, antennas are polarised. So rotating it might help as would small changes in position as reflections and absorbtion at 2.4GHz will be something that might affect the signal, just like with wifi (same frequency block).

    As for touching it - you are either acting as a passive conductor for the rf since you might be in a place with better signal strength either that or the additional capacitance of your body is improving the resonance of the antenna. Difficult to tell which, but my guess would be the former.....

  • Hello @skywatch

    I really wish that was the case :(; I have several other antennas (like ~5-6 and tested each one and its always the same)

    So the behavior goes like this:
    If the antena is folded I have a connection (most of the time, sometimes it gets lost). (you can see I have a connection by looking into the screen where I draw the battery and a wifi symbol ^^"

    alt text

    If the antenna is straight up you can see that there is no connection
    alt text

    YET, when I touch it (and keep touching it), the connection gets established? 🤔 🤔

    alt text

    Its worth noting that the RF settings are set like this:


    And that the RF24 module with the antenna is shielded with aluminum paper and grounded to the base of the antenna.

    Any other thoughts / ideas I should check / experiment with? 🙂

  • Guys I noticed that if I touch the plastic case with the antenna and leave it, it stays connected; something like static energy is interfering with it to make a connection? 🤔

    This topic is quite esoteric (to me), would it make sense to "earth" the whole shield of the module to the plastic? 🤔 (it doesnt make any sense to me though)

  • @naruse GO through every bit inside and make sure that all grounds are connected to each other. A faulty grounding can have effects like this too....

  • You might wanna try to wrap the module in plastic tape and then alu foil around it and then ground the foil.
    Or set PA level to LOW

  • @skywatch Thanks for this suggestion!, indeed I had the NRF24 ground separate from the other whole system. I think this fixed it! I will be testing it out, many thanks! 🙂

  • @iguaan I have it wrapped as you mentioned and soldered to the ground. Curiously enough I have the PA set to HIGH (had it set to LOW), but from my understanding, by setting it to HIGH the "power" of the antena is better no?, hence the reception should be better. or what am I missing?

    Thanks for the feedback as well 🙂

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