Abstract: A tunable selective heterodyne receiver which receives an input signal and is capable of supplying such input signal through one or two receiving channels and wherein in the first channel a first mixer receives a tunable input from an injection oscillator and supplies it to a second mixer which receives an input from a fixed frequency oscillator and the output of the second mixer comprises a fixed IF and wherein the second receiving channel comprises a third mixer which receives the input signal and also receives an output from a frequency divider which receives the output of the tunable injection oscillator and which has a dividing factor which is determined by the center frequency of a first band pass filter at the output of the first mixer divided by the center frequency of the fixed IF, thus, allowing a receiver tunable over a very broad frequency range.