L1, Q1, L2 and L3 compose an RF amplifier stage that feeds M1, a doubly balanced mixer. Q4 is a local oscillator stage in the 375-MHz range. Signals in the 420- to 450-MHz range from Q1 are mixed in M1 and fed through filter L6/L7/C17, where only the 60- to 70-MHz (CH3/CH4) signals pass. The IF signal is passed to Q3, and IF amplifier. The overall gain is 25 dB and the noise figure less then 2 dB.