IC-7300 Public Web Receiver
The OE6VAG IC-7300 Public Web Receiver provides interactive access to a real Icom IC-7300 amateur radio transceiver. Visitors can explore the HF bands, adjust the receiving frequency and operating mode, view the spectrum and listen to live radio signals directly in their web browser.
Unlike the autonomous monitoring systems at OE6VAG, which continuously receive and decode predefined radio signals, this receiver is operated interactively. The visitor decides which frequency to monitor.
The IC-7300 is normally switched off. A controlled session-management system powers up the radio when requested and automatically shuts it down again. Public operation is strictly receive-only.
🌐 Listen to HF Radio Live
Explore the amateur radio bands using the OE6VAG IC-7300. No dedicated radio-control software is required – just a modern web browser.
Open IC-7300 Live Receiver → Receive only · One visitor at a time · Maximum session duration: 60 minutes📻 The Icom IC-7300 Receiver
The Icom IC-7300 is a direct-sampling SDR transceiver covering the HF amateur radio bands and 50 MHz. Although the radio is capable of transmitting during normal amateur-radio operation, the public OE6VAG interface is specifically configured for reception only.
The receiver uses the actual RF hardware installed at the OE6VAG station. Audio and spectrum information therefore originate from signals received locally, rather than from an online recording or a simulated software receiver.
The web interface is based on wfweb, adapted for unattended public operation. It provides browser-based radio control, spectrum visualization and live audio.
Available Receiver Functions
- Interactive frequency tuning within the permitted receiving range
- Selection of supported reception modes
- Live spectrum and waterfall visualization
- Live audio reception through the browser
- Receiver control without installing desktop software
- Automatic session termination and power-off
Reception quality depends on the antenna, local interference and HF propagation conditions. Fading and noise are part of real shortwave reception.
Technical Overview
| Receiver | Icom IC-7300 |
|---|---|
| Receiver technology | Direct-sampling SDR transceiver |
| Public operation | Interactive HF reception, receive only |
| Radio control | USB / Icom CI-V |
| Audio | USB audio delivered to the browser |
| Receiver software | Modified wfweb with RX-only protection |
| Control platform | Linux receiver gateway |
| Power switching | Shelly network-controlled power outlet |
| Access | Browser verification and exclusive session control |
| Maximum session | 60 minutes |
| Web delivery | HTTPS through the OE6VAG web infrastructure |
⚡ On-Demand Operation
Keeping a full amateur-radio transceiver powered continuously for occasional web visitors would consume unnecessary energy.
The OE6VAG receiver therefore uses an on-demand concept. A Shelly network-controlled power outlet switches the IC-7300 power supply, while a dedicated Linux session controller supervises the complete operating sequence.
How a Listening Session Works
- Request access: The visitor opens the receiver page and completes human verification.
- Reserve the receiver: The server checks whether the station is available. Only one active visitor session is permitted.
- Power on: The controller switches on the receiver power supply through the Shelly outlet.
- Verify safe reception: The modified receiver software starts and confirms the required TX-inhibit condition before the receiving interface becomes available.
- Listen: The visitor can tune the receiver and listen to the live HF signal.
- Automatic shutdown: When the session ends, times out or loses its required browser activity for an extended period, the controller stops the receiver software and powers down the radio.
A session is limited to a maximum of 60 minutes. In addition to the software timer, the power-control system uses a separate delayed power-off mechanism as a fallback.
🔒 Receive-Only Safety Concept
Providing public access to a transceiver requires more than simply removing a transmit button from the user interface.
The IC-7300 is a fully transmit-capable amateur-radio station. However, public visitors must never be given a way to activate its transmitter.
The OE6VAG installation therefore combines several protective measures:
- Modified wfweb software: Transmit-related controls and commands are disabled or blocked in the public receiver build.
- TX inhibit: The required transmit-inhibit state is checked before a listening session is made available. A failed safety check prevents normal session startup.
- Verified software version: The session controller checks the cryptographic SHA256 fingerprint of the installed receiver executable before starting it.
- Server-side session control: The receiver is not exposed as an unrestricted radio-control endpoint. Access is managed by a dedicated web gateway.
- Automatic shutdown: Session expiration and power-control timeouts prevent abandoned sessions from keeping the equipment powered indefinitely.
The public interface is deliberately limited to reception functions. Transmitting remains outside the public operating concept.
🖥️ System Architecture
As with several other OE6VAG projects, the public IC-7300 receiver is not implemented as a single application running directly on the web server.
Instead, radio control, web publishing and development/backup functions are separated across small Linux computers.
Receiver Gateway
A small Dell Wyse 3040 running Debian Linux is located close to the radio equipment. It handles the USB connection to the IC-7300, runs the modified wfweb software and manages the browser sessions.
Local Python services implement the session controller, receiver gateway, safety checks and communication with the Shelly power switch. systemd supervises the required background services.
Public Web Server
The OE6VAG web server handles public HTTPS access using Caddy. It forwards permitted receiver requests to the dedicated receiver gateway over the local network.
Ghost provides this technical project page and the normal OE6VAG website content. The interactive receiver application itself runs independently of Ghost.
Development and Backup Server
A separate Intel N100 Linux system is used for source-code management, development archives, verification and centralized NAS backups.
This system is not part of the normal live radio-control path. The public browser communicates through the web server to the receiver gateway.
Receiver Software and Web Integration
The receiver application is based on the open-source wfweb project, which provides a browser interface for compatible radio equipment.
For OE6VAG, the software has been adapted specifically for public, receive-only operation. The currently deployed RX-only binary is based on the internally tested Hotfix 07B.2.
Additional software around wfweb provides functions not covered by a conventional locally operated radio-control application:
- Human verification before public access
- Exclusive receiver reservation
- Server-enforced session duration
- Shelly-based power management
- TX-inhibit verification before receiver access
- Receiver startup and shutdown supervision
- Browser-session monitoring
- Audio reconnection after temporary interruptions
This separation also makes it possible to update the public web interface independently of the lower-level radio-control software.
🔧 Development and Testing
The public receiver evolved through a series of local tests, software modifications and controlled live sessions.
Particular attention was given to preventing unwanted transmission, handling interrupted sessions and restoring the radio to a powered-off state after use.
The development process includes automated tests for session control, web gateway behavior, receiver proxy functions, audio recovery and safety-related startup conditions.
The deployed receiver software and configuration are backed up together with the surrounding system services. Separate versioned archives preserve tested development milestones, while scheduled NAS backups protect the current operating state.
Operating Notes
- This is a shared receiver. If another visitor has an active session, the station may be unavailable.
- Startup is not instantaneous. The radio must power on, the receiver software must start and the safety checks must complete.
- Sessions are temporary and automatically end after the selected duration or the maximum permitted time.
- Reception is affected by normal HF propagation conditions and local interference.
- The public receiver cannot be used for transmitting.
Related OE6VAG Projects
The IC-7300 receiver complements the autonomous stations and other experimental radio systems documented on this website.
👉 Radio Monitoring – Autonomous Stations
Start Listening
The OE6VAG IC-7300 brings a real HF receiver into your browser. Select a listening session, explore the spectrum and experience live shortwave reception.
Open Live HF Receiver →OE6VAG – Amateur Radio Station. Private, non-commercial radio experimentation, reception and technical documentation.