Building a portable APRS iGate/digipeater

Question

I've been experimenting with APRS for the last year or so. There are a lot of areas that I go that don't have digipeaters or iGates. (Luckily, I live about three blocks from one, so around home I'm good!)

I'm debating building a portable iGate/digipeater... something I can deploy wherever I stay for a few days that can get packets online and repeated, if there isn't good APRS infrastructure nearby. I'd prefer that this would run under Linux, as that is my preferred operating system.

What suggestions can you make for hardware and software? Something Raspberry Pi-based might be pretty inexpensive to build, and portable, but I'm open-minded.

Answer 1

A Raspberry Pi running Direwolf is definitely a reasonable option.

For a receive-only iGate, a number of people have had success with a Pi and an RTL-SDR dongle, running rtl_fm and direwolf. Nice and easy, no fuss, but of course it won't digipeat.

I recently built myself a setup using a Pi and the DRA-818V chip (specifically, SV1AFN's DRA-818V board), with a USB soundcard to go between them, and that's worked pretty well too. I use it as a mobile node, not a digipeater, and with only 1W of transmit power, it arguably wouldn't make a very good digipeater.

You could of course try adding an amplifier to that setup, but it's probably a better idea to hook up to a proper radio (perhaps an HT, or a little mobile rig). As long as the radio has some external way to operate the PTT, the same setup of Pi + direwolf + USB sound card will work fine. Direwolf will drive a rasPi GPIO for PTT, so you can generally rig something up using no more than a transistor or two. Or you could use something like a SignaLink in place of the USB soundcard, at the cost of a bit more bulk.

Answer 2

The RX iGate with a RTL-SDR dongle is pretty easy to setup. The hard part of a TX digipeater is keying the radio,like hobbs mentioned.

I bought a Argent data systems t3-micro in hopes of making a fill-in digipeater or using a spare mobile radio for TX while driving; depending on that I needed. I should get back to that project...