Somebody asked about POR. Point of reference I believe.

At this end a receive only i-Gate has been running for a couple of years on a RPi model A. The receiver being a RTL-Dongle and the set-up is located in the loft so protected from the elements. The OS is running RW but I haven't had any issues.

More recently, I have added a separate Digi-peater/i-Gate combo using a RPi v4 (overkill I know) in a passive heatsink type case plus a Baofeng UV5RE. This is connected to a 2M beam pointing north which wasn't covered by other local digi-peaters.

So a few thoughts to build up the POR. It sounds as if your digipeater is just that and isn't a combo (digipeater/i-gate) so you probably won't even need to worry about Ethernet/WiFi for internet. Although if WiFi is available on the RPi you can connect to it in hot-spot mode for maintenance. The digi-peater will pass all traffic back to the main iGate over the air.

As Craig (KM6LYW) said earlier, limit the moving parts. So passive cooling and if possible, pin diode TX/RX switching. Enable the ToT on the radio. Short as possible. I also built the board as described on the Direwolf documentation that uses a 555 timer to restrict the TX time. In my case, to 3 seconds. Weatherproof the set-up. Back-up the SD card to an image on your PC but also keep a second prepared SD card with the remote setup.

?

Tom

G0JSV