Biography

Passionate about radio communications for many years, I enjoy the hobby as a dedicated SWL . Located in Grid Square JO10jg, I spend my free time exploring the HF and VHF bands, listening to signals from near and far, and continuously improving my receiving setup to achieve the best possible performance.

Each station heard is like a new journey across the airwaves. I place great importance on accurate and detailed reception reports, and I would like to sincerely thank all stations for confirming my reports with QSL cards, whether paper or electronic. Receiving a QSL confirmation is always a great pleasure and a strong motivation to continue this wonderful radio adventure.

Looking forward to listening to you on the bands.
Many thanks for your QSL confirmations.

AUTHENTICITY SWL :

www.eqsl.cc/qslcard/DisplayAGCertificate.cfm?TestHamID=1821199&TestCallsign=F81251


73 to all!


New project 2026:

Wideband HF SWL Station under Linux – Optimized Reception Using Crossed Active Loop Antennas
This project presents a wideband SWL (Short Wave Listening) station designed to cover the entire HF spectrum (LW, MW, SW), with a strong focus on signal-to-noise optimization and weak signal (DX) reception.

Hardware Platform
The station is built on a stable and efficient system suitable for intensive SDR processing:
• OS: Kubuntu 24.04
• CPU: Intel i7
• RAM: 16 GB
• Display: dual large screens
This setup enables smooth operation with multiple virtual receivers, real-time spectrum display, and waterfall visualization without performance limitations.

SDR Receiver
The core of the system is the SDRplay RSPduo.
Key features:
• dual independent tuners
• excellent HF dynamic range
• strong performance in noisy environments
• support for dual tuner and diversity modes
The RSPduo is specifically chosen for its ability to efficiently utilize multiple antennas simultaneously.

Antenna System: Optimized Active Loops
The station uses two modified active loop antennas:
• K180WLA (North/South orientation)
• MLA-30+ (East/West orientation)
Modifications:
• copper conductor reinforcement
• addition of ferrites to improve HF behavior
• overall optimization for noise immunity
Goal:
extend the usable performance of these antennas across the HF spectrum, beyond their stock configuration.

Reception Architecture
Dual Tuner Mode (primary use)
• Tuner A → N/S loop
• Tuner B → E/W loop
Enables:
• real-time signal comparison
• exploitation of loop directivity
• signal direction assessment
• QRM mitigation via antenna selection

Diversity Mode (experimental)
• combining both antennas
• phase and gain adjustments

• noise reduction
• improved SNR on weak signals

SDR Software
The system runs SDRconnect under Linux.
Advanced usage:
• multi-VRX operation
• wideband spectrum analysis
• propagation monitoring (QSB, fading)
• experimentation with networking and modules

SWL Activities
The station is used for:
• full HF coverage (LW / MW / SW)
• long-distance DX reception
• weak signal monitoring
• digital signal decoding (FT8, RTTY, etc.)
• spectrum surveillance and propagation analysis
The approach is intentionally broadband and exploratory, without restriction to a specific type of signal.

Performance and Results
The combination of antenna modifications and dual tuner operation provides:
• significant local noise reduction
• improved signal-to-noise ratio
• better intelligibility of weak signals
• effective directional discrimination
Crossed loop antennas offer a clear advantage in noisy environments, especially in urban or semi-urban locations.

⚙️ Limitations and Future Work
• limited integration with logging software
• diversity mode requires fine tuning
• SDRconnect still under active development
Planned improvements:
• automation via WebSocket API
• integration with logging tools
• refined diversity optimization
• development of an advanced DX workflow

Conclusion
This project demonstrates that combining:
• a high-performance dual tuner SDR
• optimized active loop antennas
• a modern Linux-based SDR environment
enables high-level performance in HF SWL, especially for weak signal reception and spectrum analysis.
A practical example of modern SWL, merging traditional radio techniques with advanced digital signal processing.

Worked DXCCs:

Equipment

ATS 25 receiver decoder 2
SDR RTL V4
Antenna: K180WLA modified in copper + Ferrites (Height approximately 2 m).
Antenna Mla30+ modified in copper + Ferrites
SDRplay RSPduo