Can Wireless LAN Amplifier be used to increase the range of RC transmitter?

Yes, bi-directional amplifiers can extend the range of your RC transmitter. Before you plan to use a bi-directional amplifier with your RC system, always check the maximum RF output power capability of your transmitter and ensure less than the maximum transmit input power of the amplifier. You might have to use addittional RF attenuator or sufficient length of coax cable to decrease the RF input  power for the amplifier. With 1 Watt output power at 2.4 GHz it is not uncommon to reach the range of 3 to 4 km.