LoPy 4 OTAA join fail on some units

  • Hello,

    We have deployed many LoPy 4 nodes and connected to private LoRa gateway. We have two units that worked well, but sometimes saw that joining has no effect on some nodes (node appears to not receive JoinAccept downlink).

    Now I have one of the failing nodes with me at office (this device never joins, so I removed from the client), and I can reproduce the exact behavior.
    I've reduced the code to the minimum needed to join a LoRa network and I can see under Loraserver application JoinRequest and JoinAccept (response from gateway). But the node isn't receiving the responses (or appears to not receive them).

    I've set MAC version to 1.0.2 on device profiles, tried to join with different SF, but at the moment I'm not having success.
    Is there any way to debug what's happening? Maybe the nodes are defective?

  • Bottom line here is that PyCom sells less than user friendly devices and provides poor documentation on use. I have been trying repeatedly to get my LoPy4 to OTAA join to no avail.

    I have scoured and tried just about every code sample on GitHub and nothing. Sadly, I did get my 32u4 feather to join with no issues whatsoever.

    This pisses me off because I dropped nearly $80 on PyCom (board, LoPy4, antenna, shipping) The forum is hardly readable. As are the docs. Just plain lousy.

  • Can you share any of your OTAA code snippets? Is it different from what the official documentation suggests? I'm having the same issue with OTAA on Lopy4 in US915 region.

  • Hello @jcaron

    Missed replying to this post, the problem was lack of power. My custom boards are powered from LiFePo4 single cell battery and charged by a solar panel.
    Confirmed that the problem was because battery emptying (if I remember the voltage was at 3.0v) so the node was failing receiving JoinAccept response.


  • @River You’ll have to provide a lot more details, including the region, the frequency plan of the network, the firmware version, the relevant parts of your code, ideally logs from the server showing the frequency and data rate frames where received/sent on, etc.

    Also, how far is the device from the gateway? What kind of antenna are you using? Did you try to connect another antenna? The antenna connectors are often quite fragile...

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