Sort of radiating beacon, long distance sensing ?

[Externet]

A beacon is usually a light source,  in a rotating enclosure blocking emission in one direction and a window on another direction.  Think of a police vehicle beacon.

 

What other 'emissions' can be/are used instead of light ?   As sound as Leslie effect, radiowaves,   magnetism ?  gamma rays ?    that can be detected at -say 50- metres away ?

[Strange]

Nowadays when I hear “beacon” I think of Bluetooth. https://en.m.wikipedia.org/wiki/Bluetooth_low_energy_beacon

If you want to get directional information you would need several so you can triangulate. 

[Endy0816]

Radio and Sonar ones are out there, commonly in use.

[Frank]

Also wifi beacons: Wi-Fi challenges Bluetooth for the beacon market | Computerworld:  https://www.computerworld.com/article/2975859/mobile-apps/wi-fi-challenges-bluetooth-for-the-beacon-market.html

 

[Enthalpy]

On 8/20/2018 at 2:41 PM, Endy0816 said:

Radio and Sonar ones are out there, commonly in use.

Ultrasound scan can be directional.

Some sonars are directional, especially for seabed mapping, and need a very wide base. Helicopter sonars are little directional because the size is few wavelengths, but submarines may have transducers over all their length.

[Endy0816]

Seen them used for navigation. Like underwater lighthouses.

The submarine locator(placed on when testing) works along the same lines.

https://en.m.wikipedia.org/wiki/Electric_beacon#Sonar_beacon

I think all they do is transmit. Not sure.