Guardian

Resilient emergency messaging over amateur radio

A Windows communication system for sending messages, files and structured emergency traffic directly over VHF/UHF FM or HF — without the Internet, Winlink or any central server.

Download Guardian · Project Status · Technical Details

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What is Guardian?

Guardian turns a Windows PC and an amateur-radio transceiver into an independent digital messaging station.

Instead of relying on the Internet or a central messaging service, Guardian communicates directly over radio.

Operators can compose an email-like message, attach files, address it to another callsign and send it across an amateur-radio network.

Guardian handles:

• radio control;
• station discovery;
• route selection;
• relay stations;
• frequency changes;
• message queues;
• VARA data transfer;
• delivery tracking.

The result is a decentralized store-and-forward radio messaging network that can continue operating when normal network infrastructure is unavailable.

Guardian is designed for licensed amateur-radio operation, experimentation and emergency-communications exercises. It is not a certified public-safety or life-safety system.

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Why Guardian?

Most digital amateur-radio applications solve one specific part of the communication chain.

Guardian tries to connect the entire workflow.

      Compose a message
             │
             ▼
       Find destination
             │
      ┌──────┴───────┐
      │              │
   Direct RF      Relay path
      │              │
      └──────┬───────┘
             │
             ▼
   Negotiate radio link
             │
             ▼
       VARA FM / HF
             │
             ▼
     Message + files
             │
             ▼
     Delivery receipt

Guardian uses short ARDOS control transmissions to coordinate stations and VARA FM/HF to move the actual payload.

The control layer answers questions such as:

• Is the destination reachable?
• Which station should receive the message next?
• Is a relay required?
• Which frequency should be used?
• Is the receiving station busy?
• Was the message forwarded?
• Did it finally reach its destination?

The operator does not need to manually orchestrate every individual step.

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What can you use it for?

📻 Direct station-to-station messaging

Send text and attachments directly between two radio stations.

No Internet connection and no central mailbox are required.

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📊 Visible, efficient payload transfer

The header shows genuine VARA byte progress for both outgoing and incoming messages. Optional payload settings provide either native VARA FILES compression or Guardian's single-pass BZIP2 compression; the two modes are mutually exclusive and BZIP2 keeps the standard ZIP whenever compression would make it larger.

After the final acknowledgement, the destination can optionally append both callsigns as a 40 WPM Morse ID.

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🔁 Store-and-forward networks

A station that cannot reach the destination directly can hand the message to another Guardian station.

The relay stores the message locally and forwards it when the next hop becomes available.

OK7AAA  ───►  OK7BBB  ───►  OK7CCC  ───►  OK7DDD
 Source         Relay          Relay       Destination

Delivery state follows the message across the network.

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🧭 Automatic and assisted routing

Guardian can determine the next hop using several sources of information:

• manually configured routes;
• a shared network topology;
• stations heard directly on the radio;
• assisted route discovery;
• experimental live network topology.

Operators can therefore build anything from a simple two-station link to a larger regional radio network.

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🚨 Emergency and structured traffic

Guardian includes structured message templates for:

• ICS-213
• ICS-214
• IARU emergency messages
• SITREP

Messages remain ordinary interoperable text inside the Guardian transport rather than being locked into a proprietary document format.

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🗺️ Situational awareness

Guardian includes an operational station map.

The map can show:

• your own station;
• recently heard stations;
• Maidenhead locators;
• radio links and message activity;
• distance and bearing;
• 50 / 100 / 200 km range rings;
• route availability;
• current network alerts.

A station can be selected directly on the map to start composing a message.

The map can also be prepared for offline operation and exported as PNG. Guardian 1.1.1 additionally recognises a manually supplied XYZ tile tree at maps\tiles\<zoom>\<x>\<y>.png beside the installed application. It remains unused until the operator selects Use manually installed map in the map window and confirms the choice; without both the files and that consent, the normal ČÚZK background behaves exactly as before.

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⚠️ Network alerts

Guardian stations can broadcast short network-wide alerts independently from ordinary mail.

Alerts can be received, displayed and relayed by other Guardian stations and can optionally be transmitted across configured channels.

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FM and HF

Guardian supports both VARA FM and VARA HF.

The same mailbox and routing model can therefore be used for local VHF/UHF networks and longer-distance HF communication.

	FM	HF
Control modem	AFSK 1200	MFSK-16
Payload	VARA FM	VARA HF
Typical use	Local / regional	Regional / long distance
Routing	✅	✅
Relay	✅	✅
Attachments	✅	✅

Guardian automatically selects the appropriate ARDOS control modem for the operating mode.

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Calling and working channels

Guardian can operate everything on one frequency or separate the network into a calling channel and a working channel.

For example:

145.500 MHz
ARDOS calling / coordination
       │
       │ stations negotiate
       ▼
145.350 MHz
VARA payload transfer
       │
       ▼
145.500 MHz
return to calling channel

With CAT-controlled radios, Guardian can perform the required QSY automatically.

Radios without CAT can still be used through an operator-confirmed tuning workflow.

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The Guardian workspace

Guardian 1.1 provides task-oriented workspaces instead of exposing protocol internals to the operator.

Home

Station status, radio and VARA connectivity, control-channel state and current operation.

Mail

A local store-and-forward mailbox with:

• Inbox
• Outbox
• Sent
• Transit

Messages can contain text, structured traffic and file attachments.

Network

One operational view for:

• Routes
• Heard stations
• Network builder
• Route discovery
• Live topology

Routes clearly show where the information came from instead of mixing permanent configuration and temporary RF observations.

Log

Operational and diagnostic information for troubleshooting radio, control-channel and payload activity.

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Shared network topology

A Guardian network can be planned centrally without manually creating a different routing table for every computer.

Define the links once:

        OK7BBB
       /      \
OK7AAA          OK7DDD
       \      /
        OK7CCC

The same topology can be distributed to all stations.

Each Guardian installation uses its own callsign to calculate the appropriate local next-hop routes automatically.

Manual routes remain available as overrides.

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Assisted route discovery

Guardian can also search for a destination that is not already present in the configured topology.

Stations cooperate using bounded multi-hop route discovery.

SOURCE
  │
  ├──► Relay A
  │       │
  │       └──► Relay B
  │                │
  │                └──► DESTINATION
  │
  ◄──────── discovered route ────────

Discovery is deliberately bounded to avoid uncontrolled radio traffic.

The resulting dynamic route is temporary and remains distinct from permanent network configuration.

In Assisted mode the source operator can review a discovered path before the payload is transmitted.

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Radio integration

Guardian supports a wide range of radios through Hamlib / rigctld.

Depending on the radio and interface, Guardian can control:

• frequency;
• mode;
• PTT;
• signal level;
• automatic QSY.

For simpler radios and interfaces, serial RTS/DTR PTT is also supported.

This makes Guardian usable with both modern CAT-controlled transceivers and much simpler FM radios.

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Radio profiles

Different radios and interfaces can be stored as named profiles.

For example:

IC-705 Portable
IC-705 Base
AIOC Handheld
FTDX10 HF

Changing station hardware therefore does not require re-entering the complete CAT and PTT configuration.

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Spectrum and waterfall

Guardian includes its own VARA monitoring window.

It provides:

• live RX spectrum;
• waterfall;
• RX/TX frequency;
• PTT state;
• VARA connection state;
• FM/HF passband scaling.

The monitor observes the selected radio input and does not independently key the transmitter.

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Designed for offline operation

The radio messaging system itself does not require Internet access.

Messages, attachments, routes, heard stations and delivery state are stored locally.

Network access is used only for optional functions such as:

• downloading updates;
• installing verified Hamlib packages;
• downloading VARA after operator confirmation;
• obtaining map tiles before offline use;
• optional Windows position detection.

Once the required software and map data are present, the core messaging system operates over radio.

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Current status

Guardian 1.1.1 preserves the 1.1.0 radio, messaging and map behaviour and adds only an explicitly confirmed, manually installed XYZ map alternative. The existing ČÚZK background remains the default.

Capability	Status
Direct VARA FM messaging	✅ Confirmed on air
Direct VARA HF messaging	✅ Confirmed on air
AFSK FM control channel	✅ Confirmed on air
MFSK HF control channel	✅ Confirmed on air
Attachments	✅ Confirmed on air
Network alerts	✅ Confirmed on air
Automatic CAT QSY	✅ Confirmed on hardware
Calling / working channel split	✅ Confirmed on air
Production channel scanner	✅ Confirmed on hardware
No-CAT / serial PTT operation	✅ Confirmed on hardware
Shared network topology	✅ Implemented
Assisted multi-hop discovery	🧪 Implemented and software tested
Live topology advertisements	🧪 Experimental

See STATUS.md for the complete engineering and field-verification record.

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Installation

Windows release

Download the latest installer:

→ Download Guardian

The Windows package already contains Python and the required Python libraries.

A separate Python installation is not required.

Windows warning

Current builds are not Authenticode signed. Windows may therefore display Unknown publisher or a Microsoft Defender SmartScreen warning.

Download Guardian only from this repository's Releases page and verify the supplied SHA-256 manifest when required.

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First start

After installing Guardian:

1. Open Operation → Station readiness
2. Enter your callsign
3. Configure the radio
4. Select RX and TX audio devices
5. Locate or install Hamlib
6. Locate or install VARA FM / VARA HF
7. Connect the radio
8. Connect VARA
9. Start the ARDOS control channel
10. Compose a message

Guardian does not automatically begin transmitting when the application starts.

RF activity is explicitly initiated by the operator.

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VARA

Guardian uses VARA as the payload modem but does not redistribute it.

VARA remains separately licensed third-party software.

The Station Readiness assistant can, after operator confirmation:

1. download the reviewed VARA archive from the official distribution server;
2. verify its expected size and SHA-256;
3. ask again before starting the vendor installer.

Guardian never silently accepts or installs third-party software.

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Hamlib

Guardian communicates with CAT radios through rigctld.

Hamlib can be installed automatically from:

Operation → Station readiness

Guardian downloads the reviewed portable package, verifies it and installs it into the Guardian application-data directory.

Administrator rights are not normally required.

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Running from source

Python 3.11 or later is required when running Guardian from source.

git clone https://github.com/bubakbubak500/ARDOS-Guardian.git
cd ARDOS-Guardian

.\setup.ps1
.\run.ps1

To create the standalone Windows build:

.\build.ps1

Output:

dist\Guardian\Guardian.exe

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Documentation

The README provides the high-level overview of Guardian.

Detailed design and implementation information is intentionally kept elsewhere:

• PRODUCT.md — product scope and operational boundaries
• STATUS.md — development history, field tests and current verification
• docs/MULTIHOP_DISCOVERY.md — multi-hop discovery
• SECURITY.md — security policy
• GitHub Releases — installers and release notes

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Safety and regulatory responsibility

Guardian automates parts of a radio communication workflow.

It does not determine whether a transmission is legal.

The operator remains responsible for:

• possessing the required amateur-radio licence;
• permitted frequencies;
• bandwidth and emission mode;
• transmit power;
• identification requirements;
• third-party traffic restrictions;
• local amateur-radio regulations.

Guardian is experimental software and must not be the sole communication system for situations involving immediate risk to life.

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Contributing and field testing

Guardian is developed around real radio operation.

Field reports are particularly useful.

When reporting a radio-related problem, please include where possible:

• Guardian version;
• radio model;
• interface;
• CAT / PTT configuration;
• VARA FM or VARA HF;
• frequency and mode;
• relevant Guardian diagnostic export.

Bug reports and development discussions are welcome through GitHub Issues.

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Guardian

Messages when the network isn't there.

From HAMs to HAMs

OK7PS / OK2IPW / OK6LZ / OK2MTV