The units used for detecting and locating clandestine transmitters started WW2 as large truck mounted facilities to hand carried units (with antennas) that fit inside suitcase-sized containers.
Modern ham groups engage in transmitter hunting as part of organized events. Bunny hunting and fox hunting are alternate names for such activities.
"Huff Duff" is WW2 technology.
https://en.wikipedia.org/wiki/High-frequency_direction_findi...
The units used for detecting and locating clandestine transmitters started WW2 as large truck mounted facilities to hand carried units (with antennas) that fit inside suitcase-sized containers.
Modern ham groups engage in transmitter hunting as part of organized events. Bunny hunting and fox hunting are alternate names for such activities.
https://en.wikipedia.org/wiki/Transmitter_hunting
How to do it: https://www.youtube.com/watch?v=PN-c5DQFuhI
Governments use much large automated facilities:
https://en.wikipedia.org/wiki/Circularly_disposed_antenna_ar... https://en.wikipedia.org/wiki/AN/FRD-10