874-MRL

The General Radio 874-MRL Mixer Rectifier Locking was introduced in Catalog R (1963) and remained available through Catalog 1978. 874-MRL is a version of Type 874-MR with locking connectors.

Type 874-MRL is a device used to mix two signals, the input signal and a local oscillator, to produce an intermediate frequency. The range of both input and local oscillator is 40 to 5000 MHz, the intermediate frequency range is up to 30 MHz.

This enables UHF signals to be monitored conveniently by radio receiver, wide-band amplifier or null detectors operating at the IF frequency. The output signal from the 874-MR passes through a rectifier, then a low-pass filter.

Maximum input from the local oscillator must be kept below 2 V to prevent damage to the 1N21 diode.

Specifications

• Operating Frequency: 40 to 5000 MHz
• Maximum Crystal Current: 5 mA
• Maximum Input from Local Oscillator: 2 V
• Cut-Off Frequency of Output Fitter: 40 MHz

Links

• Experimenter May 1950 describing Type 874-MR
• Experimenter October 1961 describing 874 Locking Connectors
• Experimenter July 1962 describing 874 Locking Connectors
• 1N21B Microwave Diode Data

Photos

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  1N21B Diode

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  Schematic