🎯 WebSDR Radio Listening
Software Defined Radio (SDR) allows you to listen to radio frequencies from around the world. Use these embedded WebSDR receivers to explore amateur radio, aviation, maritime, and other radio communications.
⚠️ Security Notice
These are public radio receivers. Do not transmit sensitive information or use for illegal monitoring. Educational and amateur radio use only.
University of Twente WebSDR (Netherlands)
One of the most popular WebSDR receivers covering 0-30 MHz
📡 University of Twente WebSDR
HF Bands: 0-30 MHz
Location: Netherlands
Features: Waterfall display, Multiple users
📻 What you can hear:
- Amateur radio communications
- Shortwave broadcast stations
- Aviation communications
- Maritime radio
- Digital modes and CW
KiwiSDR Network
Global network of high-quality SDR receivers
📡 K3FEF Pennsylvania, USA
East Coast USA coverage, great for DX
📡 DJ0ABR Germany
European coverage with strong signals
🌍 Browse All KiwiSDR Receivers
Explore the global network of KiwiSDR receivers
WebSDR Resources & Tools
Directories and tools for finding more WebSDR receivers
🌐 WebSDR.org
Official WebSDR directory with receiver listings
📚 RTL-SDR.com
WebSDR listings and SDR community resources
📡 SigIDWiki
Signal identification and WebSDR guide
🎯 Additional Receivers
More WebSDR receivers around the world
🔓 SDR Hacking & Security Research
Educational content on Software Defined Radio security research and testing methodologies
⚠️ Legal & Ethical Notice
This content is for educational and authorized security research only. Always ensure you have explicit permission before testing any systems. Unauthorized interception, jamming, or manipulation of radio signals may violate local, national, and international laws.
📡 SDR Security Overview
Software Defined Radio (SDR) devices can be used for both defensive and offensive security research. Understanding RF protocols and signal analysis is crucial for modern cybersecurity professionals.
⚔️ Attack Methodologies
🔍 Passive Attacks (Legal for Research)
- Signal Analysis: Analyzing publicly transmitted signals to understand protocols
- Frequency Scanning: Mapping the RF spectrum to identify active communications
- Protocol Reverse Engineering: Understanding proprietary wireless protocols
- Traffic Pattern Analysis: Studying communication patterns without decryption
⚡ Active Attacks (Requires Authorization)
- Replay Attacks: Capturing and retransmitting valid signals
- Signal Jamming: Disrupting communications (often illegal)
- Protocol Injection: Sending crafted packets to test security
- Man-in-the-Middle: Intercepting and potentially modifying communications
🛠️ Tools & Hardware
🔧 Recommended Hardware
RTL-SDR (~$25)
Best for: Beginners, passive monitoring
Range: 24 MHz - 1766 MHz
Capabilities: Receive-only, excellent for learning
HackRF One (~$300)
Best for: Intermediate research, transmit capabilities
Range: 1 MHz - 6 GHz
Capabilities: TX/RX, half-duplex
BladeRF 2.0 (~$420+)
Best for: Advanced research, high performance
Range: 47 MHz - 6 GHz
Capabilities: Full-duplex, FPGA programming
💻 Essential Software
GNU Radio
Visual signal processing framework for creating custom SDR applications
Universal Radio Hacker
Complete suite for wireless protocol investigation and penetration testing
GQRX
Real-time spectrum analyzer and receiver for exploring the RF spectrum
Inspectrum
Tool for analyzing captured signals offline and identifying modulation types
📚 Practical Guides
🎯 Getting Started with SDR Security Research
- Setup Environment:
- Install GNU Radio and supporting tools
- Configure RTL-SDR with proper drivers
- Test with GQRX spectrum analyzer
- Legal Frequency Analysis:
- Start with ISM bands (433 MHz, 868 MHz, 915 MHz, 2.4 GHz)
- Analyze your own IoT devices
- Practice with publicly available signals
- Protocol Analysis:
- Capture signals with Universal Radio Hacker
- Identify modulation schemes (ASK, FSK, PSK)
- Reverse engineer packet structure
- Security Testing:
- Test your own devices for vulnerabilities
- Implement replay attack protections
- Validate encryption implementations
🔒 Common Vulnerability Types
🔓 Rolling Code Vulnerabilities
Many garage doors and car key fobs use predictable or flawed rolling code implementations that can be exploited through signal analysis and replay attacks.
📡 IoT Device Weaknesses
Smart home devices often transmit unencrypted data or use weak authentication, making them vulnerable to eavesdropping and control hijacking.
🔑 Weak Encryption
Some wireless protocols implement cryptography incorrectly or use outdated algorithms that can be broken with sufficient signal analysis.
📱 Proximity Attacks
RFID/NFC systems may be vulnerable to relay attacks, cloning, or unauthorized reading from extended distances.
⚖️ Ethical Guidelines & Best Practices
✅ DO
- Only test systems you own or have explicit written permission to test
- Follow responsible disclosure practices for vulnerabilities
- Respect privacy and only capture necessary data for research
- Use isolated test environments when possible
- Document your research methodology for reproducibility
- Stay informed about relevant laws and regulations
❌ DON'T
- Test systems without proper authorization
- Interfere with critical infrastructure or emergency services
- Retain personal data captured during testing
- Use findings for malicious purposes
- Ignore local RF transmission regulations
- Publish detailed attack methods without considering impact
📖 Learning Resources
📚 Books
- "Software Defined Radio for Engineers" by Travis Collins
- "The Hobbyist's Guide to the RTL-SDR" by Carl Laufer
- "Penetration Testing with the HackRF One" by Dominic Chell
🎓 Online Courses
- GNU Radio Academy tutorials
- RTL-SDR.com learning modules
- Coursera SDR specializations
🛠️ Practice Labs
- Set up controlled IoT testing environment
- Practice with ISM band devices
- Build GNU Radio flowgraphs
⚠️ Final Disclaimer
This educational content is provided for legitimate security research and defensive purposes only. The techniques described should only be used in authorized testing environments or on systems you own. Unauthorized use of these techniques may violate:
- Federal Communications Commission (FCC) regulations
- Computer Fraud and Abuse Act
- Local and international telecommunications laws
- Privacy and wiretapping statutes
Always consult with legal counsel and obtain proper authorization before conducting any security testing involving radio frequency communications.
📻 Frequency Information
Amateur Radio Bands
- 80m: 3.5 - 4.0 MHz (Voice, CW, Digital)
- 40m: 7.0 - 7.3 MHz (Voice, CW, Digital)
- 20m: 14.0 - 14.35 MHz (DX, Voice, CW)
- 15m: 21.0 - 21.45 MHz (DX, Voice, CW)
- 10m: 28.0 - 29.7 MHz (Voice, CW, FM)
Shortwave Broadcast
- 49m: 5.95 - 6.20 MHz
- 41m: 7.20 - 7.45 MHz
- 31m: 9.40 - 9.90 MHz
- 25m: 11.60 - 12.10 MHz
- 19m: 15.10 - 15.80 MHz
Utility & Emergency
- Maritime: 2-30 MHz (Ship-to-shore)
- Aviation: 108-137 MHz (Air traffic control)
- Emergency: 121.5 MHz (Aviation emergency)
- Weather: 162.400-162.550 MHz (NOAA)
🔧 WebSDR Usage Tips
- Use the frequency input box to tune to specific frequencies
- Try different modulation modes (AM, USB, LSB, CW, FM)
- Adjust the bandwidth for better audio quality
- Use the waterfall display to visually see signals
- Higher frequencies (HF) work better during daylight hours
- Lower frequencies work better at night due to ionospheric propagation
🔐 Security & Legal Notes
- Only listen to frequencies you're legally allowed to monitor
- Do not record or share encrypted/sensitive communications
- Respect privacy and amateur radio operating procedures
- Use for educational and hobby purposes only
- Some frequencies may require amateur radio license to transmit