> The most common suggested method was the detection of a signal from the TV's local oscillator.
See: superheterodyne receiver. Most modern radio receivers generate high-frequency signal for tuning, which leaks as radio signal (receiver becomes in some way a transmitter). However, it's not confirmed if these vans had working detectors, or were just for intimidation.
There were also stories about:
- Radar detector detectors (in places where radar detection devices in cars were illegal)
- Broadcast radio receivers detectors installed near roads to measure popularity of radio stations among drivers
See: superheterodyne receiver. Most modern radio receivers generate high-frequency signal for tuning, which leaks as radio signal (receiver becomes in some way a transmitter). However, it's not confirmed if these vans had working detectors, or were just for intimidation.
There were also stories about:
- Radar detector detectors (in places where radar detection devices in cars were illegal)
- Broadcast radio receivers detectors installed near roads to measure popularity of radio stations among drivers