cd2rxu igate screen 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

 

cr2rxu igate config digi 

 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
ota  username  OTA "On the air" update login
   password  OTA password
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 lora igate black

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 lora igate red

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 lora igate green

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:

cd2rxu igate OTA

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.
icons8 error 16WARNING: 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 :

GitHub CD2RXU
Password generator for  APRS