← Regions map
SA selector
Explainer
Why Regions ?
A practical Australian explanation for why the region selector exists, using South Australia examples.
Flooding is simple, but not free
In MeshCore, a public-channel message does not travel through one central server. It travels over radio. Your device transmits it, nearby repeaters hear it, and each repeater forwards it once.
That is a good design for a resilient community mesh. The trade-off is that airtime is shared. A single chat message in a dense area can occupy the channel many times: once from the sender, then once again for every repeater that forwards it.
So the aim is not “put every repeater in every region”. The aim is to keep traffic local unless it genuinely needs to go wider.
Our local pressure point
European explainers often talk about the 868 MHz 10% duty-cycle limit. That exact regulatory limit is not the main Australian framing for this site, but the practical lesson still applies: the radio channel is finite.
On the SA network we are already seeing the effect. When RX utilisation climbs into roughly the 35–40% range, the public channel starts to struggle: ordinary chat becomes harder to send, and repeater admins can have trouble getting management messages through.
Regions are one of the cleanest tools we have to stop one busy area, noisy node, or oversized public scope from chewing up the shared channel for everyone else.
SA example: broad parent, local child
South Australia starts with broad fire/weather regions, then can use council/LGA regions beneath them where that helps local traffic stay local.
au
└─ au-sa
└─ au-sa-adl Adelaide Metropolitan
└─ au-sa-adl-pae Port Adelaide Enfield
└─ au-sa-mlr Mount Lofty Ranges
└─ au-sa-mlr-mtb Mount Barker District Council
If you only need to talk around Mount Barker, use the Mount Barker LGA region. If you need a wider hills audience, use Mount Lofty Ranges. If it is genuinely statewide, step up to SA.
Boundary regions need care
Some councils and suburbs sit across fire/weather boundaries. For those, the selector keeps one canonical child region for naming stability, but the generated commands can allow meaningful extra parent regions.
Alexandrina Council : allows Mount Lofty Ranges and Murraylands.Coorong District Council : allows Upper South East and Murraylands.City of Playford : keeps Mount Lofty Ranges as canonical, with Adelaide Metropolitan added as a manual practical override.Pastoral Unincorporated Area : stays at parent fire/weather level, rather than becoming its own LGA child.
Rule of thumb
Send as local as possible, as wide as necessary.
Use the smallest region that includes the people or repeaters you need. Larger regions should be deliberate, not the default.
For repeaters, only carry the regions the site genuinely serves. Border sites may need two parent regions; a repeater tagged with every nearby region just rebuilds one large busy network.
Inspired by KiekR’s “Why MeshCore Needs Regions” explainer, adapted here for Australian/SA operating conditions and the regions.themesh.au hierarchy: kiekr.app/why-regions .
