Build an AllStarLink Node with Raspberry Pi: Linking Repeaters and Hotspots Over the Internet

AllStarLink is an amateur radio system that links repeaters, simplex nodes, and personal hotspots together over the internet using Asterisk (the same open-source PBX software that powers a lot of VoIP telephone infrastructure) as its backend. Where Winlink moves email-style messages and MMDVM-based digital hotspots bridge DMR/D-STAR/Fusion networks, AllStarLink is specifically about linking plain analog FM radio audio — your voice, keyed up on a local repeater or simplex frequency, carried live over the internet to another linked node potentially across the country or the world, and back again in real time, just like being on the same local repeater. A Raspberry Pi is the standard, well-supported platform for running a personal AllStarLink node, and this project builds a complete simplex node you can use to link into the wider AllStarLink network from a local radio.

How AllStarLink Differs From MMDVM Hotspots

If you've already built an MMDVM-based digital hotspot for DMR or D-STAR, it's worth being clear about what AllStarLink is and isn't. MMDVM hotspots translate a specific digital voice protocol (DMR, D-STAR, System Fusion) into IP packets for that protocol's own network. AllStarLink instead treats the radio interface as a plain analog audio device — the Pi's URIx or similar radio interface board captures your radio's receive audio and PTT-keyed transmit audio directly, the same way a scanner or a simple repeater controller would, and Asterisk routes that audio stream to other linked nodes. This means AllStarLink works with any analog FM radio you already own — no digital-capable radio required — but it also means voice quality and linking behavior feel more like traditional repeater linking (IRLP, EchoLink) than like a digital voice network.

Parts List

[Raspberry Pi 4 (4GB or better)](https://www.amazon.com/s?k=Raspberry+Pi+4+4GB&tag=42308b-20)
[MicroSD Card, 32GB, High Endurance](https://www.amazon.com/s?k=32GB+high+endurance+microSD+card&tag=42308b-20)
[USB Radio Interface Board (URIx-style, or DMK URI Compatible)](https://www.amazon.com/s?k=USB+radio+interface+board+URI+repeater+controller&tag=42308b-20)
[Raspberry Pi 4 Official Power Supply](https://www.amazon.com/s?k=Raspberry+Pi+4+official+USB-C+power+supply&tag=42308b-20)
[VHF/UHF Mobile Radio or Repeater (as the RF side of the node)](https://www.amazon.com/s?k=VHF+UHF+mobile+transceiver+amateur+radio&tag=42308b-20)
[Shielded Audio Cables (3.5mm to appropriate radio connector)](https://www.amazon.com/s?k=shielded+3.5mm+audio+cable&tag=42308b-20)
[Raspberry Pi Case with Cooling](https://www.amazon.com/s?k=Raspberry+Pi+4+case+with+fan&tag=42308b-20)
[Ethernet Cable (wired connection strongly preferred over WiFi)](https://www.amazon.com/s?k=cat6+ethernet+cable&tag=42308b-20)
[12V Power Supply for Radio](https://www.amazon.com/s?k=12V+power+supply+amateur+radio&tag=42308b-20)

Choosing Your Radio Interface Hardware

The critical piece of hardware unique to this build is the radio interface — a small board that sits between the Pi's USB port and your radio, carrying receive audio in, transmit audio out, PTT keying, and often carrier-detect (COS) signaling. The most common options are a genuine or clone URIx board, a DMK URI, or a repeater-controller-style interface board with built-in USB sound device functionality (so the Pi sees it as a standard USB audio device rather than needing a separate sound card plus GPIO wiring for PTT). Whichever you choose, confirm it's explicitly documented as AllStarLink/app_rpt compatible before buying — this is a mature ecosystem with well-known supported hardware, and going off that list means troubleshooting audio level and PTT timing issues yourself instead of following an established wiring guide.

Installing AllStarLink

AllStarLink publishes a ready-made Raspberry Pi image (AllStarLink 3, built on a current Debian base) specifically for this purpose — this is the strongly preferred path over trying to compile Asterisk and app_rpt from source on a generic Raspberry Pi OS install, since the official image handles the many small configuration details (audio driver quirks, real-time kernel considerations, correct Asterisk module set) that trip up manual installs.

Download the current AllStarLink Raspberry Pi image from the AllStarLink project's site and flash it to your microSD card using Raspberry Pi Imager or balenaEtcher.
Boot the Pi with the radio interface board already connected via USB, and complete first-boot setup over SSH (the image ships with SSH enabled by default for headless setup — change the default password immediately).
Register for an AllStarLink node number at the AllStarLink portal — this requires your amateur radio callsign and license validation, similar to a Winlink registration, and issues you a unique node number that identifies your station on the network.
Run the node's initial configuration wizard (accessible via the Pi's built-in web admin interface once networked) to bind your issued node number to the local Asterisk configuration.

Wiring and Configuring the Radio Interface

Connect the interface board's receive-audio input to your radio's speaker or discriminator audio output (a discriminator tap, where your radio supports it, gives cleaner audio than the speaker line, particularly for CTCSS/DCS tone handling), and its transmit-audio output plus PTT line to your radio's microphone input and PTT control, per your specific radio and interface board's wiring documentation — these connections vary enough by radio model that following a wiring diagram matched to your exact hardware combination matters more than any general guidance here. In the node's rpt.conf configuration, set receiver and transmitter audio gain levels conservatively at first and adjust using a local test — key up from a second radio and watch the node's live audio level indicators (available through the web admin interface) rather than guessing.

Linking to Other Nodes

Once your node is on the network and configured, connecting to another node or a public linked hub is done with simple DTMF commands sent over your local radio while keyed into your node — for example, keying up and sending *3 followed by a target node number connects you to that node, and *1 followed by a node number disconnects. AllStarLink maintains a public node directory and status page showing which nodes are online and linked, which is the standard way to find active, permission-granting nodes and public hub/conference nodes to try linking with as you're learning the system.

Keeping the Node Reliable

Use a wired Ethernet connection, not WiFi, for a node you intend to leave running unattended — this removes an entire class of intermittent connectivity problems that are painful to diagnose remotely.
Give the Pi a static IP or a DHCP reservation on your router so its address doesn't change and break any port forwarding or remote administration you've set up.
Set up a UPS-backed power supply if the node is meant to stay useful during a local power outage — this is a common configuration when a node is specifically intended for emergency-communications backup linking.
Monitor Asterisk's logs periodically for repeated connection failures or audio level warnings, which usually surface hardware wiring issues before they become a total node failure.

Safety and Licensing Notes

Operating the RF side of this node requires a valid amateur radio license appropriate to the band and power level in use, and any repeater or simplex frequency you transmit on must be one you're authorized to use — check local repeater coordination and, if linking into someone else's repeater system rather than a private simplex node, get explicit permission from that repeater's trustee first, since AllStarLink linking traffic on a repeater affects every other user of that repeater, not just you.

A well-built AllStarLink node turns a single local repeater or simplex frequency into a doorway onto a much larger network, and pairs naturally with the MMDVM digital hotspot and Winlink projects covered elsewhere on this site — many serious ham radio operators running a home "radio room" Pi cluster end up running several of these services side by side, each covering a different linking technology.

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