Low-Noise 420Mhz Atv Receiver/Converter
Ll, Ql, L2, and L3 compose an RF amplifier stage that feeds Ml, a doubly balanced mixer. Q4 is a l
ocal oscillator stage in the 375-MHz range. Signals in the 420- to 450-MHz range from Ql are mixed in Ml 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, an IF amplifier. The overall gain is 25 dB and the noise figure less than 2 dB.