Depends on which SKU you’re running, but here’s the short version.
For SKU-1 (SD Card): a Raspberry Pi 4 with 2GB RAM is the confirmed
minimum, 4GB Pi 4 or a Pi 5 is recommended. You’ll also want a display
(1080p minimum, 4K looks great if you have it) and either WiFi or
wired Ethernet – wired is more reliable for anything running 24/7.
Since SKU-1’s primary use case is headless, a display isn’t even
required if you’re planning to access it via browser from another
device on your network.
For SKU-2 (Live USB Stick): any Intel or AMD PC with a 2GHz dual-core
processor or better, 2GB RAM minimum (4GB+ recommended), and a USB
port that can boot from it (USB 3.0 recommended for speed, but not
required).
For SKU-3 and SKU-4: nothing to worry about – the hardware ships
ready to run.
First boot is meant to be simple by design: insert the SD card or plug
in the USB stick, power on, and Helioclock comes up on its own. You’ll
be walked through a first-run setup for your QTH, callsign, and time
zone the first time it starts.
Full specs are also on the System Requirements page on the site if you
want the complete breakdown.