Spectrum surveys
We walk your site with calibrated receivers and produce an occupancy picture: what is transmitting, on which channels, how often, and how strong at which points in the building.
Everything nearby is transmitting. Most of it is unencrypted.
Signal Gate builds software-defined radio systems and open tooling that sweep the free spectrum, identify the devices on it, and tell you when something changes.
rtl-sdr · 2.4 Msps
peak -62 dBm
433.920 MHz
Simulated waterfall. The real ones look about like this, with worse noise and more to explain.
Block Aconsulting
What we do
Six things, and we would rather do them properly than list twenty. Most engagements combine two or three.
Device identification
Preamble timing, channel-hop patterns, framing quirks and clock drift are usually enough to tell one make of sensor from another without decoding a single payload.
Custom SDR builds
Hardware selection, antenna and filtering, GNU Radio or custom DSP, and the packaging that turns a bench experiment into something an operator can run.
Continuous monitoring
Fixed sensors, capture retention, baselines per band, and alerting when a new emitter appears or a known one stops. Deployed on your infrastructure, not ours.
Clear-traffic review
Plenty of industrial and building systems still send status in the clear. We show you what a passive listener in your car park can read, and what it would take to close that.
Team training
Hands-on with the same stack we deploy: SDR fundamentals, capture discipline, demodulation, and the legal boundaries your team needs to work inside.
Block Bhow an engagement runs
Four stages, roughly six weeks
The order matters. Scoping the bands first is what keeps the survey from turning into an open-ended fishing trip.
Stage 1 · week 1
Scope the bands
Which frequencies are in play, what you already know is deployed, what you are actually worried about, and what the law permits us to record.
Stage 2 · weeks 2–3
Survey on site
Receivers on the ground, walked and fixed. Raw IQ retained where it matters so findings can be re-examined later rather than taken on trust.
Stage 3 · weeks 4–5
Build the receiver
A monitoring setup tuned to your bands and your buildings, with the identification rules your survey actually justified.
Stage 4 · week 6
Hand over the stack
Your hardware, your servers, our code under an open licence. Runbooks, a walkthrough for the team, and no dependency on us to keep it running.
Block Copen source
The tooling is public
We do not sell a black box. Everything we deploy is published, so you can audit what it records and keep running it after we leave.
gatectl
Sweep scheduler and capture daemon. Drives one or many receivers, writes retention-aware IQ, exposes a plain HTTP API.
binhound
Occupancy analysis over captured sweeps. Builds per-band baselines and flags emitters that are new, missing, or moved.
ident-db
An open catalogue of RF fingerprints for common building, industrial and consumer devices. Contributions welcome.
waterfall-web
Browser waterfall and spectrum viewer that reads gatectl output. No install on the operator machine beyond a browser.
Block Dwhere this gets used
Who calls us
Utilities and industrial control
Telemetry links that predate anyone currently on staff, still running and still in the clear.
Campus and facility security
Door controllers, duress buttons and sensor networks that nobody has listened to since installation day.
Manufacturing floors
Interference hunting when a wireless process link starts dropping and nothing in the logs explains it.
Research and regulators
Occupancy measurement for people who need the raw captures and the method, not a summary slide.
Block Esample output
What a sweep actually produces
A rolling detection log from a two-day survey of a mixed-use site. Keep scrolling the panel and it keeps loading — a real survey fills this faster than anyone can read it.
FrequencyBandModInferred deviceFirst seen
loading next block…
Illustrative data, generated in the browser. No captures are transmitted from this page.
Block Fcontact
Tell us what you are trying to find out
A sentence or two about the site and the bands you care about is enough to start. We will say plainly if it is not something we should take on.
- Coverage
- On site across the region, remote elsewhere
- Typical survey
- Six weeks, two engineers
- Licensing
- Apache-2.0, MIT, CC-BY
- Receivers
- RTL-SDR, Airspy, HackRF, USRP
- Scope
- Passive receive only, within the law of the site