LoRa testing - what equipment is best



  • Hi Guys, thanx a lot for answering my lame questions. We are now getting to the point where we're going to want to test our system. So, for the RF testing, we are planning to use an SDR to look at the transmitted signal the LoPy generates. So my question: Is there a specific SDR unit people prefer to use for testing, and examination of the transmitted signal? I see a lot of Waterfall like displays in some of the test results people are getting. My next question is the antenna. We are purchasing a number of different antennas, and want to know what other people are using and which ones they prefer. There's a lot out there, but my hardware designer guru says a lot out there is rubbish. So looking to understand whats best, is important for us. Our transceiver usage will be a unit carried in a back pack, so initially, our gateway will live in that, but relay units would be placed in high places, and powered by a 1 watt solar panel, and be remotely configured and programmed. In this application, battery power is a big concern for us. We are not planning to use any LoRaWAN networking, since we cannot depend on the Internet for our application. What kind of power management does the latest LoPy4 hardware support? Now that we understand a lot better, the mechanism between the hardware and python, is giving us a lot more options and choices for deploying better battery management.

    JD


  • Global Moderator

    @jdcrunchman I see that you leared to split your text in secitions:

    about SDR: That is only needed if you have doubts on whether RF is happening at specific times and frequencies. Normally, you can expect that, so RF testing is not mandatory. besides that, I have good experience with the model SDRplay RSP2pro. The deviecs is only as good as the software, and the supplied software works well with Windows. There hiccups with Linux. A SDR will not tell you about precise timing of RF bursts. For that, an oscilloscope give better results. If just the presence of a RF signal is to eb detected, usinf a small signal Schottky diode (e.g. 1N5711) as Antenna allows using a low bandwith oscilloscope.

    about the Antenna: Depends on your application. For a node, it may have to be small, for a gateway, the antenna gain may have to be the most important factor. Given the huge link budget of LoRa devices, a few dB antenna gain more or less may be not that important. So proper RF design, placement and orientation of your set-up may have a larger impact. I tested a few small antennas from different sources, and they all behaved similar. The PyCom Lora antenna works fine, and being a wavelength/2 design, the RF properties of the LoPy enclosure are not so critical.

    Supply by Solar Panel: You would need an external charger between Solar Panel and battery:
    Solar Panel -> Charger -> Battery -> Lopy



  • @jcaron Hi, I'm totally a newbee on the use of this forum. So where can I find information on how to add "newlines" to my post.

    I agree with you on the inadequacies of the 1 watt solar panel to keep up with the power requirements, and still reading up, and trying to understand the features of the LoPy board, because power management is definitely our concern, thus was why we are considering our own hardware design to address these issues, and thus our need for access to the source code.

    As far as my initial posting, I also asked about whether or not an SDR would be useful for testing the board. But thanx for replying to my message.

    John



  • @jdcrunchman you should add newlines in your posts, that would make it much easier to read. You also have many different questions in there.

    I’ll just comment on the solar-powered gateway. I’m quite certain you won’t get the lifetime you are hoping for on a 1W solar panel. Average output of that panel will probably be lower than the average power draw of the gateway.

    I’m also not sure I understand your comment regarding LoRaWAN?



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