Signalsintelligence
Anything that transmits can be found. Collection is passive, so it leaves no trace. And encryption hides what you said, not that you said it.
Field reports on how the spectrum is read, located and defended, each built around a working demo. Receive-only, every method legal. The trace to the right is synthetic.
The track log
what's on fileTune the band
drag the dial // what lives whereA log dial from the FM band to 2.4 GHz. The marker snaps to the nearest service; each one is a report.
Weather satellites
Low-orbit weather satellites that paint an image line by line as they pass overhead. The NOAA APT birds were decommissioned by August 2025; the method still teaches the ideas.
Field reports
11 in this track // newest firstFrequency Hopping: Hedy Lamarr's Trick for Beating Jammers and Interceptors
Instead of sitting on one frequency, a transmitter hops across many on a pseudo-random sequence only it and its…
Open report →Fixed Codes, Rolling Codes, and RollJam: Beating a Remote Without Breaking Its Crypto
How a key fob's radio burst decides whether a recording can replay it: fixed codes fall to the simplest attack there…
Open report →GPS Is a Clock, Not a Map: How It Works, and How It's Spoofed and Jammed
Every GPS satellite just broadcasts the precise time; your receiver's position falls out of the tiny differences in…
Open report →Is More Gain Better? Overload, the Noise Floor, and the ADS-B Sweet Spot
More gain is not more signal. Past the sweet spot it raises the noise floor as fast as the signal, overloads the…
Open report →The Intercept Chain: Why Metadata Is the Intelligence Encryption Cannot Touch
The pipeline from a transmission to usable intelligence, as a stepper, forking into ELINT (what the signal is) and…
Open report →What Can You Legally Receive? Scanners, the Law, and Why Digital Is Not Encrypted
Receiving the open spectrum is broadly legal; recording, divulging, using or decrypting is where the law bites. A…
Open report →Pulling Signals Out of the Air: A Legal SDR Capture Field Guide
Three receive-only captures anyone can reproduce: aircraft broadcasting position on 1090 MHz (ADS-B),…
Open report →Phantom Signals: Images, Aliases, Spurs and Intermod
Why you see stations that are not there. Four phantoms, four mechanisms - the mixer image (analog), the ADC alias…
Open report →A Bearing Is a Line: How Direction Finding Turns a Transmission Into a Location
A single receiver measures a bearing - a direction, not a distance - so one antenna draws a line and it takes several…
Open report →How a Software-Defined Radio Actually Works: IQ, Nyquist, and the Waterfall
A twenty-dollar dongle becomes any radio because it digitises a slice of spectrum and does the rest in software. This…
Open report →How Information Rides a Radio Wave: Modulation and the Spectrum, From Scratch
The foundation piece for the RF/SIGINT cluster. Every wireless device does two things: it impresses information on a…
Open report →Track console
shell // guest sessionTry help, random, latest, grep <term>, or count.