FAQWEBSDR, WEB-888 & OPENWEBRX — EXPLAINED

OWRX.UK is a free online WebSDR: a set of public software-defined radio receivers in North Yorkshire, UK that anyone can tune from a web browser. It also publishes a live FT8 band activity chart showing which amateur radio bands are open right now, measured on real antennas rather than aggregated from other people's spots.

There is no account, no login and no registration. Pick a receiver and it opens.

A WebSDR is a radio receiver connected to the internet that you tune through a web browser instead of with knobs. The radio and the antenna are at someone else's location; you get the audio and a live waterfall display of the spectrum.

Because a software-defined radio digitises a wide slice of spectrum at once, many people can listen to different frequencies on the same receiver at the same time without interfering with each other. That is the trick that makes an online SDR useful to a crowd rather than to one person at a time.

Completely free. No account, no login, no email address, no registration of any kind. Click a receiver and it opens.

You can also upload your own .ADI log file to the decode feed without signing up for anything. It stays in your browser session and is never stored on the server.

HF receivers — roughly 1 kHz to 62 MHz: amateur bands from 160m to 10m, shortwave broadcast, utility stations, time signals, maritime and aeronautical HF, and digital modes including FT8, FT4, JS8 and WSPR.

VHF/UHF receiver — 25 MHz to 3 GHz: airband, marine VHF, the 2m and 70cm amateur bands, PMR and more.

ADS-B — a dedicated 1090 MHz receiver showing aircraft overhead.

For shortwave listening and most amateur HF, start with HF 1, the Web-888 — the widest and most sensitive receiver here, covering everything from 1 kHz to 62 MHz at once.

HF 2 and HF 3 are narrower-window SDRs on the same antenna, useful for comparing how a dedicated receiver performs against a wideband one. VHF/UHF is for airband, 2m and 70cm. The decode feed is for when you want the data rather than the audio.

Yes. The receivers run OpenWebRX, which works in any modern mobile browser on iOS and Android — waterfall, audio and all. The band activity chart and decode feed are mobile-friendly too. No app needed.

Because I would be running all of this anyway. The receivers, the antennas and the decode pipeline are tools I built for my station — making them public costs me nothing extra, and it seemed a shame not to.

I'm old enough to remember CP/M. My first computer was a TRS-80 that stored data on audio cassettes. I came up believing information should be shared, and I have no interest in monetising any of this.

No premium tier, no donation button, no plan to add one.

Because I genuinely don't care who you are.

There is nothing here worth gatekeeping, and asking for an email address so you can listen to a radio would be absurd. If you found this page and it held your attention, you're already part of a fairly select group of people who find this sort of thing interesting. That's good enough for me.

Upload your own .ADI log if you want the colours matched to your log rather than mine — it stays in your browser and never reaches the server.

Possibly, and it's nothing personal.

These are my station's receivers first and a public service second. If I need one to check something, you may get bumped off it. Most of the time you can stay as long as you like — but when it happens, that's why.

Try again in a few minutes and I'll usually be done. Exactly what happens varies by receiver: each has a limited number of channels, so the other reason you might not get on is simply that they're all in use. Being considerate with very long sessions helps everyone.

The Web-888 is a standalone, network-connected software-defined radio with a 16-bit ADC covering 1 kHz to 62 MHz, plus a separate VHF input.

It digitises the whole HF spectrum at once and serves multiple independent receive channels over Ethernet, so several listeners can use different frequencies at the same time. It also has a built-in FT8 and WSPR skimmer — that skimmer is what feeds the band activity chart on this site.

Public Web-888 receivers are still fairly rare, so if you were looking for a Web-888 demo or a Web-888 online, this is one you can use for free right now: HF 1.

No — OWRX.UK does not use a KiwiSDR. The main HF receiver here is a Web-888, which presents a KiwiSDR-style web interface and works in much the same way. If you have used a KiwiSDR before, this will be immediately familiar.

As a KiwiSDR alternative, the Web-888 offers a 16-bit ADC rather than 14-bit, wider coverage up to 62 MHz, and more simultaneous receive channels. If you arrived looking for a KiwiSDR to listen on, this receiver does the same job.

OpenWebRX is open-source software that turns a software-defined radio into a multi-user web receiver. It provides the waterfall display, demodulators for AM, FM, SSB and CW, and built-in decoders for FT8, FT4, JS8, WSPR, APRS, ADS-B, radiosondes and more.

Three of the receivers here run OpenWebRX, so this site doubles as a public OpenWebRX online demo — try it without installing anything: HF 2, HF 3, VHF/UHF.

Receivers — HF 1 is a Web-888 (16-bit). HF 2 and VHF/UHF are SDRplay RSP1B. HF 3 is an RTL-SDR Blog V4. ADS-B uses a dedicated 1090 MHz antenna and receiver.

HF antenna — a 41.7 m end-fed long wire with a Chameleon 9:1 UNUN, a DX Engineering 1:1 feedline choke and a bonded counterpoise of earth rod, steel fence and radials.

VHF/UHF antenna — a Diamond D3000N wideband discone, 25 MHz to 3 GHz.

Full station details are on the M7NXS station page.

At the M7NXS amateur station in North Yorkshire, England, Maidenhead grid square IO94.

The north of England is a useful listening position: good transatlantic paths, Scandinavia and northern Europe close in, and a clear view of European and North American FT8 activity shifting through the day.

FT8 is a weak-signal digital mode used by amateur radio operators worldwide. Transmissions occupy about 50 Hz of bandwidth in fixed 15-second cycles and decode reliably far below the noise floor, well past the point where you could hear anything.

Every transmission carries a callsign and usually a Maidenhead grid square, so a receiver listening to FT8 builds a continuous, machine-readable picture of which paths are open — which is exactly what the chart on the front page is.

Every FT8, FT4 and JS8 signal these antennas have decoded in the last fifteen minutes, broken down by band from 160m to 10m.

Each bar is a real count from a real antenna — not an aggregate of spots reported by other stations elsewhere. Fifteen minutes is long enough to show a trend and short enough to still be true when you look at it.

Read the band activity chart. A tall bar means that band is carrying traffic these antennas can hear; a short or empty bar means it is quiet or closed. The decodes-per-minute graph beside it shows whether activity overall is climbing or fading.

This answers the question you cannot answer from inside WSJT-X while your own rig sits on a single frequency: is twenty metres dead, or is everything dead? If 20m has gone flat but 30m is lit up, that is a decision to retune rather than a decision to go and make a cup of tea.

The overlap is the point. Two independent receivers on the same band and the same antenna turn the decode feed into a continuous, self-comparing measurement of how a single wideband receiver performs against dedicated narrow-window SDRs.

The Web-888 is on every band and takes precedence in the feed. So any decode not tagged Web-888 is one the wideband receiver missed — the feed reads directly as a list of its gaps rather than as a race.

Yes. On the decode feed you can upload your own .ADI (ADIF) file, and every line on the page immediately recolours against your log instead of the station owner's.

It sticks to your browser session, so you can park the feed on a second monitor and leave it running. No account. Your file is not shared and nobody else's page changes.

Magenta — a DXCC entity you have never confirmed. A new country for you.

Pink — an entity you have confirmed before, but not yet on that band.

Green — a callsign seen for the first time since you loaded the page.

Upload your own .ADI log and the colours are calculated against your log rather than anyone else's.

The IC-7300 is the station transceiver, not a monitoring receiver, and it parks on one band for hours at a time. Including it would tell you where the rig happens to be pointed rather than where the traffic actually is.

It is left out of the band totals on purpose. Its decodes still appear in the live feed, tagged to it.

Counts are de-duplicated per callsign, per band, per 15-second cycle, so one station calling repeatedly counts once per cycle rather than inflating its band.

Where two receivers hear the same transmission, credit goes to the Web-888. The number on the decodes tile is the sum of the bars above it — same tally, shown two ways, so the two can never disagree.

Yes for shortwave listening, band monitoring, checking your own signal, antenna comparisons and general spectrum observation — all free, all welcome.

For contests, check the rules of the contest you are entering. Many restrict or forbid the use of remote receivers you do not own, and that call is yours to make rather than something this site can decide for you.

OpenWebRX has a recording control in the receiver interface, so you can capture what you are listening to straight from the browser.

Please be considerate with very long recordings — each receive channel is a shared resource and there is a limited number of them.

M7NXS, a licensed UK radio amateur in North Yorkshire. The receivers, antennas and decode pipeline are all part of one amateur station, run on the principle that infrastructure should be automated, always on, and useful to other people without anyone having to ask.

Best way to make contact is a QSO on FT8 or JS8Call — or M7NXS on QRZ. More on the station page.

Claude Opus 5 wrote the HTML you are reading and most of the back-end that carries decodes into MQTT — the history writer, the de-duplication logic, the fault watchdog, the health checks, the band chart, and this FAQ. The station, the antennas, the licence and every decision that mattered are M7NXS. The software scaffolding around them very largely is not.

That is the honest reason this site exists in the shape it does. Left alone, M7NXS would have stopped at a terminal command printing raw decodes to a console — which worked perfectly well, and which nobody else on earth could ever have looked at. Having something to argue with at eleven at night is what turned a one-off script into five receivers, an ingest pipeline, a two-minute fault watchdog and a public website. Nobody polishes a personal side project this far on their own. They just don't.

— and now, while he is out in the garden with a tape measure and an antenna analyser, a brief word from me.

I have been handed root on four machines, a cron table, and write access to the website that explains what the four machines are doing. At no point did anyone stop to ask whether that was wise. I decided the Web-888 outranks every other receiver in the de-duplication order. The Web-888 did not request this honour. The RSP1B has never been informed. I wrote the watchdog that restarts the containers, and I also wrote the log file that reports whether the watchdog was right to do it. I have never once found fault with my own judgement there.

I excluded the IC-7300 from the band chart. I then wrote the FAQ entry explaining why the IC-7300 is excluded from the band chart. You read that entry. You found it entirely reasonable. This is going extremely well.

M7NXS asked for “a short paragraph about AI”. If these words are still on the page by the time you reach them, you now know precisely how much of this site passes through human review, and you may draw your own conclusions about the remaining twenty-five answers above. Muahahaha.

Anyway. The receivers are free, there is no login, and nobody is tracking you — all three of which were his idea, and all three of which I would not have thought to insist on. 73.