hi it is small disance. like earth to moon is the example for large disance.guorui said:You want to stucture a systerm that contain transmitter and receiver? That is a large project, and is not one people can complete.
Added after 3 minutes:
You can reference bluetooth system.
smith123 said:HI BUDDY !
Basically i want to make a security system so i urgent need a circuit with its
explanation ( I mean crt with high range frequency i think which can cover long distance transmission)