how to make transmitter and receiver for quad copter?
The APC220 radio module provides a simple and economic solution to wireless data communications. Integrates an embedded high speed microprocessor and high performance IC that creates a transparent UART/TTL interface, and elminates any need for packetizing and data encoding. Use this module as this works as a pair and more intriguing part is that "it" can transmit over a km away.

link ~http://www.dfrobot.com/index.php?route=product/product&amp;filter_name=apc&amp;product_id=57#.VWeKIVWqqko