OpenWebRX+ HF Enhanced
Vadelma RX is a locally enhanced OpenWebRX+ receiver focused on Airspy HF+, HF broadcast listening, DXing, signal analysis and a purpose-built receiver interface for serious shortwave listening.
Welcome to Vadelma RX. Vadelma RX I and RX II are locally enhanced OpenWebRX+ receivers featuring my own Airspy HF+ optimizations, DX-oriented receiver controls, signal-analysis tools and a custom VadelmaRX user interface designed specifically for HF broadcast listening and DXing.
Vadelma RX I is available at Vadelma.live, while Vadelma RX II is available at Vadelma.lol. Both receivers are located in Kangaslampi, Jyväskylä, Finland.
Vadelma RX I uses an Airspy HF+ Discovery connected to a K-480WLA active loop antenna. Vadelma RX II provides the second VadelmaRX receiving system with the same enhanced OpenWebRX+ interface and integrated DX tools.
The RX I loop amplifier is battery powered. If no signals are visible on the waterfall, the amplifier battery is most likely empty. I try to recharge it as soon as possible, so please check back later if the receiver appears unusually quiet.
Airspy HF+
- AGC modes: Low, High and Manual
- Manual RF gain from 0 to −48 dB
- Optimized Airspy HF+ sample rates
- Runtime receiver control directly from OpenWebRX+
Smart Noise Reduction
- Custom Speech NR profile
- FFT-based signal and noise analysis
- Smart Auto NR
- Automatic NR adjustment according to signal quality
Smart Bandwidth
- Manual 4 / 6 / 8 / 10 kHz presets
- Custom filter detection
- Smart Auto BW
- Automatic bandwidth selection using smoothed FFT SNR
DX-Focused Receiver Controls
- Receiver modes reordered for broadcast and DX listening
- AM, SAM, LSB, USB and DRM placed first for quick access
- Compact Airspy HF+ AGC, RF, bandwidth and EQ controls
- Receiver panel optimized for fast tuning during DX sessions
VadelmaRX UI Theme
- Custom VadelmaRX user interface theme integrated into the native OpenWebRX+ theme engine
- Deep navy and petrol-blue instrument-style colour palette
- Warm orange accent for active receiver modes and selected controls
- Cyan and blue-grey accents reserved for signal analysis and status information
- Custom control surfaces for AGC, RF gain, bandwidth and audio EQ
- Available directly from both the receiver UI and OpenWebRX+ settings
- Designed to retain the familiar OpenWebRX+ layout while giving VadelmaRX its own visual identity
VadelmaRX DX Waterfall
- Custom waterfall colour theme optimized for HF DX monitoring
- Very dark navy noise-floor region for a calm low-level background
- Expanded blue and cyan range to improve visibility of weak carriers and marginal signals
- Teal, green and muted yellow transitions for medium-strength signals
- Warm orange and red tones reserved for stronger signals
- Designed to preserve useful visual dynamic range instead of turning weak signals into a rainbow display
- Works together with the existing optimized FFT, overlap and automatic waterfall-level settings
- Available as VadelmaRX DX Theme alongside the standard OpenWebRX+ waterfall themes
Vadelma Watch
- Dedicated toggleable DX analysis panel integrated into the OpenWebRX+ receiver UI
- Four compact analysis cards arranged in a 2 × 2 layout
- SNR Watch – live 60-second SNR history with peak, fade depth and trend direction
- Signal / Noise – simultaneous signal and noise-floor tracking using a shared scale
- 5 Min Trend – longer-term SNR behaviour with average, direction and minimum / maximum values
- Events / Peaks – records only meaningful events such as SNR peaks, fades and noise changes
- Signal-state classification including Stable, Improving, Fading and Noise Rise
- Subtle colour coding for rapid visual interpretation without distracting from listening
- Opened from the dedicated Watch button in the receiver header
Shortwave SKED
- Integrated shortwave broadcast schedule directly inside the OpenWebRX+ receiver UI
- Automatically follows the currently tuned receiver frequency
- Live schedule data provided by Shortwave.sbs
- Displays the matching station, broadcast time, schedule, language, target area and transmitter site when available
- Frequency changes automatically trigger a new schedule lookup
- Stale results are ignored if the receiver is retuned while a lookup is still in progress
- Compact schedule card positioned directly below Vadelma Watch for quick DX identification
- Opened from the dedicated SKED button in the receiver header
- Available on both Vadelma RX I and Vadelma RX II
Audio EQ
- Client-side Web Audio equalizer
- Flat – neutral reference audio
- Speech – improved speech presence
- Warm – relaxed program listening
- DX – enhanced intelligibility for weak signals
S-Meter
- Native HF S-unit scale
- S9 = −73 dBm reference
- Smoothed meter movement
- Fast peak indicator
- S9+ dB display
Vadelma Spectrum
- Expanded 120 px spectrum display
- Custom signal-level colour palette
- Enhanced filled spectrum with bright signal trace
- 10 dB reference grid with live dB scale
- Receiver passband overlay
- Live noise floor, signal level and SNR display
- Center-frequency reference line
- Strongest live signal marker with dB readout
- Optional spectrum peak-hold tracking with slow decay
- Peak Hold state remembered locally by the browser
- Implemented as a local OpenWebRX+ receiver plugin
- Visual styling coordinated with the VadelmaRX UI and analysis colour system
DX Status Bar
- Always-visible compact receiver and propagation overview
- Live geomagnetic Kp index from NOAA space weather data
- Live planetary A index for geomagnetic activity
- Current tuned-channel SNR shown directly in the status panel
- Colour-coded bar indicators for quick visual assessment
- Kp, A and SNR integrated alongside the native OpenWebRX+ status meters
- Designed as the lightweight overview layer, while Vadelma Watch provides deeper signal analysis when needed
Receiver Session Recovery
- Current receiver profile remembered locally in the browser
- Current tuned frequency remembered before an unexpected WebSocket disconnect
- Automatic profile restoration after WebSocket reconnection
- Tuned frequency restored after the correct receiver profile has reloaded
- Prevents reconnects from falling back to the default receiver profile