FM Scan Monitor

FM Scan Monitor by Aurel is a standalone desktop and mobile FM band scanner, reception logger and reporting plugin for FM-DX Webserver.

Desktop	Mobile

FM Scan Monitor 0.9.27 — persistent FM scanning, reception monitoring and shared results for desktop and mobile browsers.

It runs beside the Webserver's existing features and uses its public plugin interfaces. It does not modify the FM-DX Webserver core and does not require the Highpoint2000 Scanner plugin at runtime.

Highlights

• Single-pass or continuous 0.1 MHz scanning using the tuner range already configured in FM-DX Webserver, with defaults of 20 dBf and 15 seconds on detected stations.
• Frequency-confirmed pacing keeps slow tuners synchronized and stops safely instead of building a backlog of later tune commands.
• After Stop, Resume scan continues the previous single or continuous run from the frequency currently tuned in the Webserver.
• Server-side scan state that survives browser refreshes, administrator login/logout and disconnected displays.
• Responsive Frequency scan list for desktop, Android, iPhone and iPad.
• Native Scan Monitor shortcut in the Webserver plugin bar that opens and reveals the frequency list or administrator panel.
• RDS confirmation and adjacent-frequency spillover suppression designed to reduce malformed PS names and false No PS entries around strong stations.
• Frequency, PI, PS, signal, reception time, transmitter city/country, distance, ERP, polarization and azimuth data when supplied by the Webserver.
• Configurable LOC, DIST and DX distance classes, plus filters and sorting by frequency, distance, signal or reception time.
• Expandable station details, direct Tune, administrator-only Hide actions and a dedicated Hidden stations view; shared hidden rules remove the same results from visitor lists and reports.
• CSV export and a complete PDF report with summary, signal bars, transmitter table, resilient topographic map tile recovery and a 206-channel activity survey for finding the quietest measured FM frequencies; reports automatically use the Webserver-selected dBf, dBµV or dBm unit, and hidden stations are excluded from both formats.
• Password-free public tuner handover: a visitor can pause a continuous scan, use the tuner for a limited time, then release it. Disconnect and timeout recovery resume the scan automatically.
• Compact live status and Pause & tune / Release tuner action inside the Webserver's existing Frequency card, with no replacement of the normal tuning arrows.
• Mutual exclusion with Highpoint Scanner: FM Scan Monitor stops it before starting, pauses when Highpoint takes control and resumes after Highpoint releases the tuner.
• Windows, Linux and Raspberry Pi OS support.

Current release: 0.9.27. See the changelog for the complete history.

Install

The release consists of two items that must stay together:

plugins/
|-- FMScanMonitorPlugin.js
`-- FMScanMonitor/
    |-- fm-scan-monitor.js
    |-- fm-scan-monitor_server.js
    |-- fm-scan-monitor-engine.js
    |-- fm-scan-monitor.css
    `-- ...

1. Download the latest release, or clone this repository.
2. Copy FMScanMonitorPlugin.js and the complete FMScanMonitor directory into the FM-DX Webserver plugins directory.
3. Restart FM-DX Webserver.
4. Sign in as administrator and open Administration > Plugins.
5. Enable FM Scan Monitor by Aurel [v0.9.27], save, and restart the Webserver once more.
6. Reload the receiver page. Use a hard refresh if an older version was previously installed.

For Updater installation, upgrades, platform notes and exact paths, read the installation guide.

First use

1. Sign in as administrator and open the Scan panel below the receiver controls.
2. Open settings and choose the signal threshold, station stop time in seconds, default results view, LOC/DX boundaries and public tuner time limit.
3. Start a single or continuous scan.
4. Expand Frequency scan list to filter, sort, inspect, tune, hide or export received stations.

The frequency range and 0.1 MHz step are intentionally inherited from the tuner/Webserver. They are not duplicated in the plugin settings.

Public visitors can view the live list without administrator access. While a continuous scan is running, the visitor uses Pause & tune directly below the main frequency display. The normal frequency and preset controls then unlock, station cards gain a Tune action and the red countdown shows the remaining control time. Release tuner, closing the last controlling tab or reaching the timeout resumes the scan. Administrators use the same prominent control to pause or resume an active scan. The original frequency arrows remain in place.

The user guide explains every control and the Android/iOS workflow.

Compatibility

• Developed against FM-DX Webserver 1.4.0b public plugin interfaces.
• Windows, Linux and Raspberry Pi OS.
• Node.js 20 or newer, as required by current FM-DX Webserver releases.
• Modern Chromium, Firefox and Safari browsers.

The plugin uses only Node.js and browser APIs. On Linux-style installations it publishes its browser assets into the Webserver's public plugin directory at startup; on Windows it detects the shared plugin junction and avoids copying files onto themselves.

Data, permissions and privacy

• Scan administration, settings, Hide and Clear remain administrator-only.
• Public users receive result snapshots but cannot change scanner settings.
• A public socket may tune only while its own temporary tuner-control lease is valid.
• Display settings remain in the browser profile. Administrator-hidden stations are stored by the plugin on the Webserver and filtered from public snapshots and reports.
• Active scans and aggregated results are held in Webserver memory. Restarting the Webserver clears them.
• PDF and CSV reports are generated locally in the browser. No report is uploaded by this plugin.
• Topographic report maps request tiles from OpenTopoMap and use OpenStreetMap/SRTM data attribution.

Development

The scan engine and asset publisher have dependency-free Node test suites:

node --test FMScanMonitor/fm-scan-monitor-engine.test.js FMScanMonitor/fm-scan-monitor-assets.test.js

See CONTRIBUTING.md before proposing a change. Security issues should follow SECURITY.md.

Credits and license

FM Scan Monitor is an original, independent implementation by Aurel. Highpoint2000 Scanner 4.7a was studied as a functional and compatibility reference, but is not a runtime dependency.

FM Scan Monitor is released under the MIT License. The bundled jsPDF build retains its own MIT notice; see third-party notices.