The aprs-igate role provides two method for running an igate. The first is a listen-only igate that relies on an SDR. The other provides a TX igate. Fluent-bit and Telegraf are used to ship logs and metrics for observability purposes.
sdr-aprs is a service that listens to APRS on 144.390 via an rtl-sdr device with rtl-fm and sends the output to a socket. Disabled by default.
sdr-igate is a listen-only igate that works with an SDR device. It listens for its data on the socket that sdr-aprs outputs to. Disabled by default.
igate is a TX igate that works with a physical radio. Enabled by default.
Configuring Direwolf can be relatively challenging, especially when working with hardware for the soundcard and a physical radio. There are two primary tasks: configuring PTT and configuring the soundcard. In both cases, the Direwolf user guide is very useful and readers should take its advice. k Configuring PTT is relatively straightforward once it is known which device is the PTT device. I'm using an Easy Digi USB device purchased from e-bay for my Yaesu FT-2980 at /dev/ttyUSB0.
It's easiest if the soundcard has the same address every time. See the usb-audio role for details about how to do that.
I'm using a Syba external sound card to provide both input and output functions. Audio levels need to be configured in alsamixer. To figure out which devices need to be configured in alsamixer, use arecord -l and aplay -l, making note of which device the soundcard is.
Adjusting the input and output level is easiest when you have another APRS capable device (e.g. I use my Yaesu FT-3DR) on hand to test sending and receiving.
Run alsamixer and then select the appropriate device. Mute the automatic gain control, AGC; be sure it is set to MM and not just 0. Adjust both the volume on the radio and the input volume on the device in alsamixer to a reasonable level. When you believe the input level is set correctly, send an APRS beacon to the igate by specifying the igate's call sign as the digipath. Direwolf will output a message to its logs if the level is too high. Adjust the input level and try again if Direwolf logs indicate the level is too high or if Direwolf logs do not indicate that the beacon was received. Next, adjust the output levels and make sure your device receives the APRS message. Repeat until the levels are correct.
After all the alsamixer levels are correct, execute sudo alsactl store to ensure the configuration gets reloaded on subsequent boots.