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Thread: Nordic nRF24 analysis with Chanalyzer

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  1. #1

    Default Nordic nRF24 analysis with Chanalyzer

    Hello,

    I recently have bought a WiSpy 2.4x in order to analyse the signals between custom-built WiFi nodes with Nordic nRF24-L01, but I failed to detect the nodes' signal in Chanalyzer.

    According to the datasheet
    and my settings, the radio signal should be around 2402MHz.

    Unfortunately, I cannot find my nodes' signal! There are lots of other signals around, but even if I go out in a silent field, I still cannot detect my nodes' signal (see the attached traces/screenshots). Hence, I think that there are 2 factors which make difficult to localise/detect my nodes' signal:
    - the various signals from the environment in the same frequency range;
    - my nodes communicate very short (one message per second).

    Moreover, I tried to detect my own WiFi signal in the planar-view while I do an intensive file transfer over WiFi, but I do not see a difference when compared to moments without transferring data!

    Could you advice me how to proceed to detect my nodes' signal?
    Is there a way that I can write/script my own message decoder based on the signal signature+header-decoding? Then I could get on VIEW the name of my nodes when their signals are detected.

    Best regards,
    Mike
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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  2. #2

    Default

    Well, due to the low duty-cycle and the very small bandwidth, you might need to run a scan for a few minutes longer to see anything.

    And for the WiFi, could you post pictures with WiFi transfer and no transfer? We might be able to help you understand what you're seeing.

  3. #3

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    Quote Originally Posted by Tyler View Post
    And for the WiFi, could you post pictures with WiFi transfer and no transfer? We might be able to help you understand what you're seeing.
    Here are 2 pictures before and after I start an ftp transfer. My signal is "Mike", and I zoomed in channel 1 on which it works.

    Please tell me how can I interpret/read the pictures.
    BTW. I also attach the recording: I start ftp after 1:00, and I stop it around 2:00.

    Kind regards,
    Mike
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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  4. Default

    Also, not to change the direction of the conversation, but I'm a little interested in what the device is from 2447MHz to 2457MHz. Seems like an odd profile.

  5. #5

    Default

    Quote Originally Posted by Trent View Post
    Also, not to change the direction of the conversation, but I'm a little interested in what the device is from 2447MHz to 2457MHz. Seems like an odd profile.
    Do you mean the red A from my first post?
    How can I find that? I really don't know how to use the analyser to detect and describe a signal with more accuracy!

    Cheers,
    Mihai

  6. #6

    Default

    Hello?
    Is anybody there able to answer my questions regarding how-to detect Nordic nRF24 signals?

    See my posts above, please.

    Thanks in advance,
    Mike

  7. #7

    Default

    I also cannot see the nodes in the recording. It's all too blurry, can you try a resolution?

  8. Default

    I think your step size is too large for the frequency range you've set. Try lowering it to 100KHz, or even lower. It is true that you would like a higher step size to make sure that you'll capture the transmission that happens once every second. Here are some configuration settings that I recommend.

    Start: 2400
    Stop: 2403

    Step Size: 100
    Resolution BW: 135

    It will give you a sweep of .07 seconds, which may not be short enough for you, but if you leave it running long enough, you'll definitely be capturing the packet transmissions, and I think you'll see enough activity.

    Also can you tell us how far you are from the intentional radiator, and what the transmit power level is? That will let us know what amplitude level we should be watching for.

    By looking at the Planar view, it is obvious that some activity is occurring at 2402. Also at the Spectral/waterfall view, you can see some points where there was a higher amplitude signal. Whether your device was it or not, I have no way of knowing. Thank you for supplying the attachments and pictures.
    Last edited by MetaGeek; 03-01-2010 at 03:13 PM. Reason: added "transmissions"

  9. #9

    Default

    Quote Originally Posted by Trent View Post
    I think your step size is too large for the frequency range you've set. Try lowering it to 100KHz, or even lower.
    Thanks for suggestions, Trent.
    Here it goes.

    you have pics before and after I used 2 of my nodes to communicate. The nodes I'm using are exactly these development kits which come with antena and I kept them around 20cm to my analyser.
    http://www.nordicsemi.com/files/Prod...ARD_rev1_0.pdf

    I also put a record, where I turned on both nodes around 1:00, turned them off around 2:00.
    I still cannot make difference between the moments I have and I don't have my nodes.

    Moreover, I'd like to know if it's possible to detect and decode the signal of my nodes (similar to WiFi scanning) which could show us the nodes' name on all views? (I'm interested in planar and spectral views because the problem is synchronization of these nodes and I'd have many of them).


    Kind regards,
    Mike
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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