Because you use light to communicate in sign language, and light is just an electromagnetic wave like radio but on another frequency. You just need to be in line of sight
Because you use light to communicate in sign language, and light is just an electromagnetic wave like radio but on another frequency. You just need to be in line of sight
Passive radar?
Fair enough, though I would argue that’s a very specific subtype of radar and anyone saying “radar” refers to the type that is used in 99.999% of the cases.
Yeah probably true. I only thought to look it up because I knew active and passive sonar was a thing.