LoRa (Long Range) Spread Spectrum Communication on 440-MHz Experiments

     Always on the lookout for modes and techniques to improve my VHF+ rover, I ran across information on the use of inexpensive modules used to communicate over long distances with a protocol called LoRa (Long Range). This technology sends packets of information in 'chirps' across spread spectrum frequencies. Although typically used for ISM purposes, an amateur radio operator can use frequencies and higher power levels with these modules.

    I started my experiments with some inexpensive Ebyte E32 433-MHz modules ordered off Ebay for $7 each. These radios will output 100-milliwatts and interface nicely with an Arduino Uno which I had on hand. Any other Arduino or even a Raspberry Pi will work with it. The initial tests were based on some proof-of-concept code which demonstrated the ability to send and receive.

        The 1-watt modules cost around $36 apiece but I found the HamShield LoRa Edition board which is set up for ham radio use. I've since ordered two of them and gifted one to N5XTR who will help work out how best to maximize the performance of this board. The HamShield Lora Edition can be found at https://inductivetwig.com/products/hamshield-lora-edition-high-power 

        Boards are available for 144, 433 and 915 MHz. Please note that spread spectrum CANNOT be used on 2 meters!

    

        I plan to start out with the following settings:

                Spreading Factor = 12

                Bandwidth = 125KHz

                Chip/Rate = 4/5

            This will yield an effective speed of 300 BPS. I can slow it down if needed.