An active surveillance radar can determine the position of the objects around itself by the time elapsed between emitted and reflexed pulse. In order to detect distant targets, the transmitter and receiver amplifiers can increase the signal strength within certain limits. In a radio transmitter system, the front end is the block located between the antenna and the first mixer, i.e. the circuit part operating in the carrier frequency of the device. In my thesis report, I designed and realized the front end subsystem (the four-channel transmitter and the four-channel receiver amplifier block) of a radar, which is capable of detecting small aircraft. I thoroughly describe the steps of the implementation process and the measurements made on the completed circuits as well as the results and their discussion. During the design, I paid particular attention to turn on and off the amplifier channels with the highest pace achievable, in other words, to switch between the transmit and receive mode of the radar as soon as possible.