Abstract: A radar receiver for indicating the presence of a source of microwave energy includes an antenna, a modulation oscillator and modulator diode, a detector diode connected to bandpass amplifier stages, a peak detector providing a signal proportional in level to the received microwave energy signal strength, and a voltage controlled oscillator (VCO) connected to the peak detector and having a frequency in proportion to the peak detector signal level, the frequency of the VCO being an indication of range from a source of radar and a change in frequency being an indication of a rate of approach thereto. The VCO controls a transistor switch, and alarm output devices are connected through the transistor with alarm power sources, whereby an alarm signal activates the output device at a frequency related to the microwave signal strength.