C4FM Secure and Professional Repeater Linking Project
Date :
01 /
02 /
2026
Author :
Peter Clee - VK8ZZ
KernWi-Fi has delivered what it describes as Australia's first carrier grade Yaesu IMRS network linking multiple amateur radio repeater sites across the VK region over an IP background.
This represents an Australian first if not a world first implementation of this system.
The rollout centres on Yaesu's Internet Linked Multi-Repeater System or IMRS which connects digital voice repeaters via an IP network. KernWi-Fi built the backbone using techniques more commonly found in commercial telecommunications networks than in amateur radio deployments.
Amateur radio groups in Australia typically link repeaters using radio frequency paths or basic internet connections, approaches that can limit redundancy and security.
KernWi-Fi's design introduces higher levels of routing control, segmentation, and failover.
The backbone uses OSPF for internal routing and DGP for external connectivity with Ethernet over IP tunnels between repeater sites. Quality of service policies prioritize audio traffic across the network. The design includes dual ISP connectivity for failover.
Each repeater site operates on isolated VLANs with firewall rules restricting traffic and uses industrial-grade routers and switches. Additional sites can be added without major redesign, positioning the deployment as a template for future repeater links and digital mode integration.
The carrier grade IP fabric for Yaesu IMRS (DR 2X) linking—over 44Net— with audited BGP announcements, rDNS hygiene, and simple operational guardrails that clubs can replicate.
The backbone centres on a managed core (Kern Data Centre) with OSPF at the edges, strict VLAN separation for deterministic voice paths, and public visibility of the 44.30.65.0/24 route originated by AS137399.
Volunteer run repeater infrastructure often relies on mixed back haul arrangements, creating inconsistencies across sites. KernWi-Fi applied stricter controls across the backbone, including VLAN segmentation to isolate repeater traffic, encryption, and firewall policies to reduce unauthorized access and centralized monitoring to limit on-site maintenance. The project aligns with a broader shift in amateur radio toward internet link systems, including digital voice ecosystems such as Wires-X that depend on IP connectivity for inter-regional coverage.
This project demonstrates how enterprise networking principles can transform amateur radio infrastructure. “By applying carrier grade standards, we've created a system that is secure, resilient, and future ready for the VK Australian community”. KernWi-Fi expects additional repeater sites to join the IMRS backbone as clubs expand coverage and link more systems into national digital voice networks.
44Net (AMPRNet) gives licensed hams globally routable, static IPv4 space for experimentation and learning — no CGNAT, no address churn, and a community committed to open, non commercial use. That’s ideal for multi site repeater linking, where stable addressing, transparent routing, and teachable network discipline matter as much as RF coverage.
ARDC’s recent investments — 44Net Portal 2.0 and 44Net Connect — also make it simpler for clubs to get started (address requests, WireGuard tunnels, and even BGP for advanced users), lowering the barrier to a real IP backbone for amateur infrastructure.
The Results so far have proven the system to be
 Reliability & determinism: Sites converge quickly on failures (OSPF), and voice remains clean thanks to segmentation and simple ACLs.
Education & adoption: Coverage by WIA and Ham Weekly drove interest and volunteer learning around 44Net and routing.
“Deliver IMRS over an IP fabric that behaves like a carrier network—predictable routing, strong isolation, and security you can audit.” — VK5PK
KernWi-Fi, is a South Australian independent Telco, that has successfully delivered Australia’s if not the world’s first carrier-grade Yaesu IMRS (Internet-linked Multi-Repeater System) network, setting a new benchmark for amateur radio infrastructure in Australia.
See a typical network diagram at the link below
Related Files
Page Last Updated: Tuesday, 03 Feb 2026 at 11:17 hours by Peter Clee
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