I have asked that question on some Facebook ham radio groups many times – and nobody was able to answer that actually. The question was how to run a standalone MMDVM Pi-Star DMR (and probably other modes) repeater with no access to the internet. First question is why? DMR system must be connected to the internet, otherwise it just does not work correctly and does not make any sense. Well, it is only kind of true.
There are two reasons of running standalone DMR repeater – in a very remote locations with no chance of having an internet access – so you can use eg. TG9 group to communicate within a direct range of the repeater.
The second reason of running a standalone DMR repeater is a natural disaster, war, alien invasion and any other random reasons.
The first thing I found – if repeater is connected to the internet (through a router) using an ethernet cable – if the cable gets unpluged, the repeater is still working locally (TG9) without any problem.
However – once the repeater restarts, and there is not access to network (even local!!!) it does not work anymore.
So instead of unplugging the repeater’s cable I did a different test. I unplugged a landline from the router. Repeater still works locally with no problem at all on the TG9 group. More importantly – restarting the repeater is fine – after the restart it works locally with no problem on TG9!
I have not tested the WiFi option yet, but it looks like as long as the MMDVM board gets the IP address assigned, the system works fine locally on TG9! So if MMDVM normally gets connected to internet through WiFi – in case of the problem with access to the internet, even after restarting the repeater it will still work locally.
So it resolves the problem for repeaters working usually with internet access. In case of the internet access problem, the local router (ethernet or WiFi) will provide IP address and the TG9 will work locally without any problem.
However, if you really want to run a repeater in a very remote location with no access to the internet, you need to add IP manually: what you have to do is:
/etc/dhcpcd.conf file to add the entries, for example:
interface wlan0
static ip_address=10.0.0.11/24
static routers=10.0.0.1
static domain_name_servers=10.0.0.1
Another solution I just found is to disable the network interfaces in Pi-Star. As long as I understand (I have not tested it myself yet) all active *network* interfaces must be switched to “0” – and you can do it here: Configuration -> Expert -> DMR GW:
