transmitters/ receivers help?

I am trying to design / build a key finder. This item finder will have 4 different transmitter frequencies with a receiver for each one. What type of transmitter and receivers are best to use for this project? Where are some of the best resources for how transmitters operate ? Help???

A very nice place to go is here: https://www.rentron.com/PicBasic/RemoteControl.htm :wink:

HI ALL
PLEASE I WANT SCHIMAT OF VHF TRANSMITTER ALL TRANSISTORS WITHOUT ANY TRANSFORMER , POWER OUTPUT ABOUT 7 or 8 Watts
thank you for all

hi for all;
please helpe me for writting the code for pic16f877 transmitter &receiver in c languge