3689686073?profile=originalWe make new modem for diy use. Can be use as a transparent UART modem. Board have also USB to UART converter.

433MHz (414-454MHz) 100mW (20dBm) Super Long Distance LoRa Wireless data modem with USB and UART interface.



LoRa LRS series is a low cost, high performance transparent transceiver with operating at 433MHz. It is LoRa/FSK/ GFSK/OOK modulation variety. It features small size, high output power, high sensitivity, long transmission distance and most of the parameters can be set via the command. Receive and send data to automatically switch. U s e generic UART interface. It is easy to realize the wireless data transmission with only providing the UART data. It is flexible for the users to set the UART baud rate, output power, data rate, frequency select, modulation mode select etc parameters. It is your ideal choice for designing wireless data transmission products which can be widely used on wireless data transmission field.



  • Low cost, high performance , high reliability
  • LoRa/FSK/GFSK/OOK modulation, 2-way half –duplex communication, strong anti-interfere
  • Frequency Hopping Spread Spectrum
  • 414-454MHz ISM band,globally license free.
  • Maximal output power100mW(20dBm),output power adjustable between 2-20dBm
  • LORA Sensitivity -139dBm
  • Supply current for Tx 130mA@20dBm, 35mA@13dBm
  • Supply current for Rx 16mA
  • Low current sleep mode 2uA
  • Standard UART interface and USB interface
  • Operation frequency can be configured, acceptable for several modules working in different frequency with no disturbance on each other.
  • RF parameters as needed, users can be modulated by software
  • Easily use, auto exchange on communication & transceiver
  • Communication speed 1.2kbps -115.2kbps,can be modulated through software
  • Afford Sleep control signal,user self control work duty cycle
  • With LED indication
  • Longer transmission distance,over 5Km in open air
  • Small size 42x30mm, USB connector and 4 pin connector for UART
  • Weight 8 gramm
  • SMA antenna connector
  • Tuning free
  • Accord FCC,ETSI standard


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  • @CSG

    Have you any findings on the topic? Any suggestion of new settings?

  • It is worst.

    There is no way it can work if I have well understood the LoRa standard.

    The Config tool shows a number of bps but in reality and due to time slots and duty cycle, the actual bps is like 10% of that.

    Anyway, empirical tests on my side give tons of lost packets and absolutely unusable link.

    It is a pity.

  • Please try set this settings

    SF 7 

    SBW 250kHz

    Code Rate 4/5

    HFSS On

    Baud rate 9600

    CRC ON

    Data length 127

  • Mavlink protocol does not have a predefined air rate. It can be adjusted by requesting a particular refresh rate for a given type of data to the autopilot.

    I have tried with FSK and 9600 and it works awesome. However with the settings for LoRa above (I think it gave like 12kbps in the setup tool) it keeps loosing packets. 

    So either the LoRa Module is not providing the air rate that is listed in the tool or the way a packet is muxed and demuxed is affecting the Mission planner parser... Go figure...

  • What air rate have Mavlink protocol?

  • I have been testing different settings and there must be a problem with mavlink framing or how mission planner or Lora Module treat the incoming bytes.

    No combination of Lora settings gives a clean and 0% packet lost. Every configuration has some degree of packet losts.

    The best one so far is COM at 9600 and Lora at 7, 500khz, 4/8 and 96 bytes per payload.

    When tested in FSK is works perfectly with 0 errors. It is a pitty as FSK is less sensitive than LoRa modulation

  • I have had problems using LoRa modulation too.
    There must be some issue with mavlink packets. Hope to find the correct setting.

    Payload size setting could be clarified? Does the module wait for input buffer to reach payload size in order to actually send it to air?
  • One of the issues with using LoRa in the unlicensed 433Mhz ISM band (which is NOT a Worldwide allocation) is that to get stable performance without using an expensive TCXO the bandwidth needs to be 41.7Khz or above, this then normally limits the ISM band usage to only 10% duty cycle, you may not transmit continuously. 

    Transmiting only 10% of the time means that the actual data throughput is very low, so to that extent I would agree with a previous poster, LoRa is really best at low data rate applications. 


    You cant know you operating legally unless you know the LoRa settings in use. 

  • There is no such a parameter as air rate in HM-TLRS-PCConfig. Are you talking about baud rate? 

  • What air rate have your software? Maybe you make buffer overflow. 

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