Online SDR Receivers
Software-defined radio receivers you can operate live, right in your browser — no downloads, no hardware, no license required to listen. Click any receiver below to open it in a new tab and start tuning.
📍 California Receivers
Verified public SDR receivers in or near Southern California. These are real, community-operated stations — uptime depends on the volunteer operators who run them.
HF receiver in the Los Angeles metro area. Covers multiple HF bands. One of the closest publicly accessible WebSDR stations to the Inland Empire. Good for monitoring SoCal HF activity.
Historic site — the former KFS ship-to-shore commercial station. Now a community-operated WebSDR with excellent low-noise HF reception thanks to its coastal location. Multiple antenna systems covering multiple bands.
🌐 Recommended Public Receivers
Well-maintained, high-quality public receivers around the US and world. Useful when local receivers are busy or offline, or for comparing propagation from different locations.
The original web-based SDR project by PA3FWM. The websdr.org homepage lists dozens of public receivers worldwide. The University of Twente receiver is one of the most famous — wide HF coverage, always busy, always on.
KiwiSDR is purpose-built hardware for shared HF reception. The map at sdr.hu (the KiwiSDR network) lists hundreds of public receivers worldwide. Most cover 0–30 MHz continuously. Excellent for propagation monitoring and DX listening.
The most comprehensive global SDR directory, aggregating WebSDR, KiwiSDR, and OpenWebRX receivers in one searchable map. Filter by band, location, or software type. Updated in real time.
OpenWebRX is open-source server software that lets operators share their RTL-SDR, Airspy, or SDRplay receivers over the internet. It supports FT8, WSPR, CW, DMR, SSTV, PSK31, and more — with built-in decoders. No client software needed.
🎧 How to Use a Web SDR
It opens in a new tab. You'll see a waterfall display — a scrolling color map of radio spectrum activity. Bright colors mean strong signals. The horizontal axis is frequency, the vertical axis is time (newest at top).
Click anywhere on the waterfall or type a frequency into the tuning box. The receiver will tune there and you'll hear audio through your browser. Make sure your browser volume and system audio are up.
Common modes: USB for HF ham voice (most above 10 MHz), LSB for HF ham voice below 10 MHz, AM for broadcast and aviation, FM for VHF/UHF, CW for Morse code. Wrong mode = garbled or no audio.
On KiwiSDR, check how many clients are connected (shown in the lower corner). If others are listening, don't change the band — you'll interrupt their reception. WebSDR and OpenWebRX typically let each user tune independently.
💡 Tips for Getting the Most Out of Web SDRs
Before calling CQ, tune a web SDR to your target frequency and listen. If you can hear stations from your target area, propagation is likely open. If the band sounds dead from a distant receiver, it probably is.
Most web SDRs require your browser to allow audio. Check for a blocked audio icon in your browser's address bar. Chrome, Firefox, and Edge all work well. Safari can be finicky — try Chrome if audio won't play.
If a nearby web SDR covers your band, you can tune it to your frequency while you transmit and hear your own signal — a useful way to check audio quality, ALC, and whether you're actually getting out.
For long-distance HF, try 20m and 15m during the day, 40m and 80m after sunset. 10m is spectacular during solar maximum (we're near one now). Web SDRs let you monitor any band without tying up your own radio.
Listening to amateur radio is completely legal with no license required. You only need a license to transmit. Web SDRs are a great learning tool for new hams studying for their exam.
An RTL-SDR dongle costs ~$25–35 and a Raspberry Pi can host OpenWebRX or a WebSDR server. You can share your receiver publicly or keep it private for personal remote access. The SoCal ham community always needs more local receivers.
💻 SDR Software for Your Own Radio
The most popular RTL-SDR frontend. Free, easy to use, huge plugin ecosystem. Great starting point for beginners.
Open-source, cross-platform SDR application. Clean interface, works with most SDR hardware including RTL-SDR.
Excellent open-source receiver based on GNU Radio. The go-to for Linux users and Mac users who want a clean SDR app.
The best resource for SDR beginners. Tutorials, hardware reviews, project ideas, and the latest SDR news. Bookmark this.
Web SDR receivers are operated by volunteers. Uptime is not guaranteed. All links go directly to the operator's own servers — KE6MGB has no affiliation with any of these stations. Listening to amateur radio transmissions requires no license; transmitting does.