ACKA 500 WATT POWER AMPLIFIER FOR A 144 MHZ CHANNEL BASED ON A VHF PUSH-PULL POWER MOS TRANSISTOR

Abstract

In a wireless communication, a signal power amplifier is needed to carry signals over a long distance. Many signal amplifiers are made of tube as the amplifying component and as such they suffer low efficiency. This study presents results of the research on designing and implementing solid state 144MHz signal amplifier employing MOSFET BLF278 as the active component of the amplifier. The amplifier has an automatic activation switch, an input terminal, a 50 ohm impedance output terminal and a bypass system for two way communication. This amplifier has been tested on frequencies between 144.00 MHz to 146.90 MHz in 100 KHz steps without adjusting the tuning. It is found that the signal amplifier delivers RF powers up to 500 watt at the working voltage of 48 volt with the efficiency of 77%. The amplifier has a Standing Wave Ratio (SWR) of 1:1 when amplifying and 1.1:1.0 when in bypass mode. The signal amplifier has been tested successfully for radio communication between Sukoharjo in Central Jawa and Surabaya in East Jawa.