Electronic Warfare on a Budget of $15 or Less

The talk opens with the physics behind radio: any wire carrying an oscillating current radiates, so nearly every everyday device is a transmitter. Wavelength tied to frequency sets the antenna length needed, and improvised field antennas cut from coax show how this works in practice. The spectrum is then sorted by band, with lower frequencies penetrating better and higher ones carrying more data.

Next comes electronic warfare, split into protection, attack and support. Encryption, jamming, directional jamming against key links, direction finding by triangulation and rapid frequency hopping are each weighed against the countermeasures they invite. Transmitters can also be fingerprinted from the startup transients of their oscillators, which reflect manufacturing tolerances. Rarer channels such as meteor burst links, skywave HF, over-horizon radar, very low frequency submarine signaling and number stations round out the section.

The second half focuses on cheap software-defined radio, which handles demodulation in software and covers a wide band for very little money. Demonstrations include plotting aircraft ADS-B broadcasts, listening to pilot messages, mapping ship AIS traffic, decoding pagers, and detecting hydrogen-line radio astronomy signals. The speaker stresses that transmitting needs filters and checks against local regulations. The closing takeaway is that the hardware barrier has collapsed, but care still matters.