Know what's transmitting on a site you're responsible for.

A straight answer about your device (browser app)

BandSight checks eight things this specific device and browser actually expose — the running environment, a secure connection, short-range wireless, tag reading, whether a receiver can be attached at all, connection state, location and offline capability — and reports each as available, limited, or not exposed. Where a capability is limited, it says how rather than glossing over it. You can save that check into the field report as a dated record of what the device could and could not do that day.

A working receiver, in the browser or on a handset

With a small USB radio receiver attached, BandSight tunes, shows a live spectrum and a rolling waterfall, and plays demodulated audio in wideband FM, narrowband FM or AM. It is a real receiver, not a visualisation — it was validated against actual hardware, receiving broadcast FM across the band and playing it aloud. Retune while it is running and it hands the radio over cleanly instead of stalling.

Fourteen survey presets (browser app)

Broadcast FM, the civil aviation band, weather satellite downlinks, marine VHF and the calling channel, vessel position telemetry, weather radio, radiosondes, the four unlicensed device bands, licence-free personal radio, and both aviation beacon frequencies — each one a tap, each carrying a short note on what lives there and how to treat it. No typing frequencies while a client watches.

Sweep a band, get a list (Android app)

Give it a start and end frequency, or tap a preset, and BandSight sweeps the range and lists every carrier it finds with its strength. Progress and a running count are shown while it works, and you can pause and resume without losing what you have found. If the range you asked for falls below the receiver's reach, it tells you that up front rather than sweeping an empty band.

Saved stations (Android app)

Anything worth coming back to gets saved with one tap — from a scan result, or from whatever you are tuned to right now. The list is searchable, supports favourites, and tapping an entry tunes straight back to it. Scan results show a tick when they are already saved, so a repeat sweep of the same site does not fill the list with duplicates.

Signal finder — walk toward the source (Android app)

A strength meter with peak hold sits on the centre of the tuned frequency, and an optional beep gets louder, higher and faster as the signal grows. That turns a number on a screen into something you can follow through a building. On a handset with a compass it also records the heading where the signal was strongest, which is how you get a bearing with a directional antenna — and it tells you plainly when no compass is present, and that a plain whip gives the same strength in every direction, so you home in by moving.

Capture what fobs and sensors send (Android app)

On the four unlicensed sub-GHz bands — 315 MHz for most North American car fobs, 433.92 MHz for European cars, gate remotes and weather sensors, and 868 and 915 MHz for tyre and other sensors — BandSight captures each short burst and slices it into bits. You get the frequency, the on-off timing, the pulse count and the raw pattern in binary and hex. An all-bands sweep locks onto whichever band a signal appears on and holds it until the burst ends, so nothing is cut off mid-air.

Device library (Android app)

Name a device, name its buttons, then learn a button by pressing the fob at it a few times — every press is captured under that button. It builds a personal reference of the transmitters you care about, so next time you can compare a live capture against what that device looked like before. Captures and saved stations both export and import as a spreadsheet, so the library travels with you.

Band reference with cautions (both apps)

Fifty-five allocations across the receiver's range, from low-frequency beacons to the top of the tuner, each carrying a plain caution: open to log freely, may carry private correspondence, safety-of-life, or restricted. Where allocations overlap the strictest caution wins, and the app names the band the caution came from — so a weather channel is not left carrying a warning that really belongs to the land-mobile band it sits inside. The same reference appears as a lookup right under the frequency field while you log.

Expected versus found (browser app)

Declare the transmitters that are supposed to be radiating — the client's fobs, meters and access points — and anything else that turns up is flagged. That is the difference between a logbook and a survey that answers a question. Entries with no frequency, such as a device capability check, are excluded from the count rather than inflating the one number that matters most.

Baseline comparison (browser app)

Load a survey from last month or last quarter and BandSight shows you what has appeared since. Matching is by frequency within a tolerance, never by record number, because a repeat survey mints new record numbers for the same physical transmitter — a comparison by record would report every emitter as new, every single time, and quietly ruin the feature.

Sessions, export, import and merge (browser app)

Observations group under a named site and a stated authorization scope — your own equipment, a client-authorized site, or public broadcast — instead of piling into one flat list. Ending a session leaves later observations unassigned rather than back-dating them into a closed survey. Export as a spreadsheet or a structured file, and merge two operators' files into one record with duplicates removed by record ID.

Imported rows are re-checked and re-cleaned on the way in rather than trusted, because a file can be hand-edited between export and import. A local report holds 250 observations before the oldest roll off.

Audio recording you can see happening (browser app)

Recording the demodulated audio is a deliberate button press, marked by a pulsing indicator and a running timer the whole time it is on — never silent capture. The file downloads as a standard audio file you keep separately; it never enters the field report or the stored record. Any single recording stops itself after ten minutes so a forgotten session cannot grow without bound, and compliance with local law stays yours.

Offline, bilingual, and nothing phones home

The browser app keeps working once it has loaded, so a basement or a rural site does not end the survey. Every screen, message and band entry runs in English and Spanish with a toggle in the header, and the choice sticks between visits. The Android app declares no network permission at all — the operating system itself will not let it open a connection, so anything it hears is physically unable to leave the handset.

Help that works offline, in both languages

Twenty guides in English and twenty in Spanish cover the receiver and its power and permissions, tuning and audio, scans, the finder, device and button libraries, recordings, spreadsheet files, deletion and recovery, and follow the language you chose.

The policies travel with the app

The full privacy notice and terms are bundled in the Android app and open from About with no connection, and the same documents are published on the website.

Spanish search that forgives accents

Typing a Spanish search term without its accents still finds the article, and the keyboard no longer rewrites what you typed (Android candidate 1.0.4/code5).