Experimental LoRA APRS ESP32 APRSDroid bluetooth modem and LoRA APRS-IS iGate

Tiny experimental amateur radio esp32 based LoRA (RA-01) APRSDroid bluetooth modem and iGate server.

Can be used in two modes:

• as a client, where you need to use APRSDroid application, connect to the modem using bluetooth, data will be re-transmitted through the LoRA radio, this is similar to APRSDroid micromodem - https://unsigned.io/micromodem/, received data will be sent back to the APRSDroid using bluetooth
• as a server, which connects to your WiFI and sends received LoRA APRS positions into APRS-IS network, it also reports client signal level, by appending it into the APRS comment

Software Dependencies

• espressif/arduino-esp32 library (install using arduino library manager)
• sandeepmistry/arduino-LoRa (install using arduino library manager)

Software Setup

• when setting up APRSDroid, use "TNC (plaintext TNC2)" connection protocol in Connection Preferences -> Connection Protocol
• go to esp32_loraprs.ino and make next changes based on your requirements
  • comment out / remove LORAPRS_CLIENT define if you are planning to run server mode iGate
  • for server mode fill LORAPRS_WIFI_SSID and LORAPRS_WIFI_KEY with your WiFI AP data
  • for server mode fill LORAPRS_LOGIN and LORAPRS_PASS with APRS-IS login callsign and pass
  • change LORAPRS_FREQ if you are planning to use different frequency, currently it is set to 432.500, which is 70cm band APRS frequency in IARU-1 region, see http://info.aprs.net/index.php?title=Frequencies
• if you are planning to use different esp32 pinouts for lora and/or different LoRA spread factor / bandwidth then modify loraprs.h
  • lora module CfgPinSs, pin 5
  • lora module CfgPinRst, pin 26
  • lora module CfgPinDio0, pin 14
  • lora bandwidth CfgBw, 20 kHz (to fit into standard 25 kHz channel)
  • lora spread factor CfgSpread, 11 (down to -17.5dB)
  • lora coding rate CfgCodingRate, 7
  • lora output power CfgPower, 20 (set to maximum 20 dBm ~ 100mW, change to lower value if needed)
• use 80 MHz ESP32 frequency in Arduino, it will prolong battery life when operating portable, higher speed is not needed

Test Results

• About 4 km when server is 30m above the ground and client is 2m above the ground
• About 13 km when server is 30m above the ground and client is at some higher point ~40m above the ground

Hardware Photos