LoRa/RFM95 - Testing long range PHY settings - Findings



  • Re: Any success story on LoRa(RFM95) module and MySensors?

    I have been testing out the RA-02 433MHz Lora modules with the Mysensors implementation.
    I setup a GPS node, reporting through the RFM95-MQTT gateway to Hassio.. All good it works well.

    I hope to eventually run two Mysensors LoRa gateways, 1 local, high speed and with multiple nodes, and another, so-called long-range mode gateway for remote sensors or GPS tracking.

    So I thought I would try some other Lora Phy settings in the hope to get better range between the mobile GPS node in my car and the gateway at home.

    I am using BW 62.5KHz, CRC Coding 4/5, Spreading factor 2048CPS (SF11).
    Messages can take up to 4 seconds long time on air.

    I tried SF12 (4096CPS) and it doesn't completely work, for some reason some presentation messages fail (NACK) such as the internal presentation version message: (2.3.2).

    I tried increasing the time-out setting, but It didnt really work, Im wondering is these long time-on-air messages are causing other time-out issues somewhere or perhaps certain payloads is causing issues.??

    Other settings:
    In Sketches:
    #define MY_RFM95_ATC_MODE_DISABLED

    In RFM95.h
    RX_PAYLOAD_CRC_ON
    RFM95_AGC_AUTO_ON
    RFM95_LOW_DATA_RATE_OPTIMIZE
    RFM95_RETRY_TIMEOUT_MS (3000ul)

    In MyTransport.h
    #define MY_TRANSPORT_STATE_TIMEOUT_MS (4*1000ul)

    I would be very interested in your comments
    P


  • Mod

    @cloolalang if you haven't seen it already, https://forum.mysensors.org/topic/8813/any-success-story-on-lora-rfm95-module-and-mysensors/ might have some good information.

    Edit: sorry, I see now that you already linked to that thread. Feel free to ignore this post.



  • Thanks for taking a look Mikeal,.
    Here's my update:

    1. I added a 47uF cap to the 3.3V input to the RA-01 Lora radios on both Node and Gateway, now the SF 12 long payload messages pass!

    2. I tested various SF and BW and coding rates, I decided on the following for the "long-range mode". Typical use will be point-point mode, or gateway to 2 or 3 nodes max, no repeaters. Horizontal polarised yagi antennas.

    • MY_RFM95_FREQUENCY 433237500ul (its 1MHz away from my co-located standard mode gateway frequency and other local ISM users).

    • RFM95_MODEM_CONFIGRUATION RFM95_BW62_5CR45SF4096 (Typical time-on-air is around 4000ms.

    • MY_RFM95_ATC_MODE_DISABLED (to reduce traffic).

    • MY_RFM95_TX_POWER_DBM 23.

    • MY_RFM95_MAX_POWER_LEVEL_DBM 23u.

    • RFM95_RETRY_TIMEOUT_MS 3000ul.

    • MY_TRANSPORT_STATE_TIMEOUT_MS 6*1000ul.

    • Passive mode = off.

    • MY_REPEATER_FEATURE = off.

    • AGC_AUTO_ON

    • RX_PAYLOAD_CRC_ON

    • LOW_DATA_RATE_OPTIMIZE.

    • CAD = Default settings.

    • Encrypton = Off

    • Signing = Off

    • Sleep = Off.

    Further test planned:

    1. 866 MHz setup.
    2. TXCO setup narrow band modes to 7.6KHz
    3. Chain network topology with repeaters.
    4. Higher RF power (Ham radio license).

    Cheers
    P


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