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CD2RXU's iGate LoRa software offers a few notable improvements over other iGates : - APRS LoRa classic gateway - gateway + LoRa transmitter broadcasting weather information. - digipeater APRS LoRa simplex ou duplex - OTA (remote software update) - mini weather station - configuration multi-WLAN - distinct APRS symbols depending on the gateway mode - etc... |
Principe :
This article is about the CD2RXUs iGate gateway.
In classic gateway mode, the gateway listens permanently to the 433.775 MHz frequency in LoRa mode, detects APRS frames (position, WX) and broadcasts them on the APRS-IS (APRS Internet Service) network via a WiFi network.
In gateway operation with transmitter, in addition to the classic function, it responds to weather report requests from the tracker.
In digipeater mode, it detects APRS frames (position only) and broadcasts them on the same or a different frequency (duplex).
Used equipment :
The software has been designed for the LILYGO TTGO T3 v1.1.6 module and works on other modules (see author's website).
Software :
The software can be downloaded from the author's GitHub site:
https://github.com/richonguzman/LoRa_APRS_iGate
To edit the configuration file and program a module, you need to use the Visual Studio Code editor/compiler.
I've given some basic instructions on how to use it in this article.
Configuration :
| callsign | iGate callsign with SSID | |
| stationMode | 1 - iGate normal, 2 = iGate + TX, 3 = digipeater | |
| iGateComment | Text sent by iGate beacon | |
| wifi | ssid | WiFi access point SSID |
| password | WiFi AP password | |
| latitude | iGate latitude | |
| longitude | iGate longitude |
| digi | comment | comment sent in digipeater mode |
| latitude | latitude digipeater | |
| longitude | longitude digipeater | |
| aprs-is | passcode | APRS password for the iGate callsign |
| server | APRS-IS server name | |
| port | 14580, APRS-IS server port | |
| reportingdistance | 30 | |
| lora | iGateFreq | frequency in Hz in iGate mode |
| digirepeaterTxFreq | frequency in Hz for TX in digipeater mode | |
| digirepeaterRxFreq | frequency in Hz for RX in digipeater mode | |
| spreadingfactor | 12- LoRa spreeding factor | |
| signalBandWith | 125000 - LoRa bandwidth in Hz | |
| codingRate4 | 5 - LoRa coding rate | |
| power | 20 - power in dBm of LoRa TX | |
| display | alwaysOn | true = permanent display. false = ecomode |
| timeout | 4 = OLED shutoff delay in sec. | |
| turn180 | false : flip the display | |
| syslog | active | false : syslog use |
| server | 192.168.0.100 : syslog server IP | |
| port | 514 : syslog server port | |
| other | beaconInterval | 15 : in min. interval between beacon transmissions |
| rememberStationTime | 30 : in min. heard stations keep time | |
| sendBatteryVoltage | true : send battery voltage in beacon comment field | |
| bme | active | false : BME280 use or not |
Usage :
iGate :
Once you've selected the gateway operating mode, configured and loaded the software + configuration into the module, operation requires no special action.
In iGate mode, on start-up the module attempts to connect to one of the configured WiFi networks.
If connection to the 1st access point fails, it tries the next access point. If none of the 2 works, it retries connections indefinitely.
If the connection is successful, the iGate displays the IP address assigned to the module, sends its beacon and switches to receive mode.
The display then shows the callsign and beacon type of the last APRS beacon received.
The gateway appears on APRS cards like 
iGate + transmitter :
In iGate + transmitter mode, gateway operation is identical, but the module also transmits LoRa weather information in response to requests from CD2RXU trackers.
The gateway appears on APRS maps like 
Digipeater :
In digipeater mode, the module decodes APRS frames and broadcasts LoRa positioning beacons only.
The transmit frequency can be the same (simplex) or different (duplex) from the receive frequency.
The gateway appears on APRS cards with 
Weather station :
It is possible to connect a BME280 sensor to measure temperature, pressure and humidity, and to transmit a weather beacon.
The connection is made in i2c mode on pins IO21(SDA) and IO22 (SCL) for a TTGO T3 module.
Modify configuration file to validate BME280 use (bme = true)
OTA update :
The gateway can be updated remotely using OTA (On The Air update) technology.
On the display, note the IP address of the gateway and connect to this IP address with a browser: xxx.xxx.xxx.xxx/update
The following screen appears:
You can update the software and/or the filesystem.
The files to be downloaded must be generated by compiling them with VSCode.
They can then be found in the /pio/build/ttgo-xxx/ folder.
The file to be used for the firmware is generated by clicking on the build button.
It generates the file : firmware.bin
To generate the filesystem file, click on "build Filesystem image".
It generates the file : spiffs.bin
Then simply select the part to be updated and the correct file.
WARNING: an error in the choice of files will render your gateway inaccessible, with all the consequences that this entails. !
For good results, you need to use a good antenna other than the small one supplied with the module.
In addition, the module radiates and therefore disturbs reception with an antenna close to the module.
In a disturbed HF environment, you also need to add a band filter to reduce receiver desensitization.
See my UHF SAW filters.
Links :