1231-P4

The General Radio 1231-P4 Adjustable Attenuator was introduced in Catalog M (1951) and remained available through Catalog P (1959). It is an accessory for the Type 1231-B Amplifier/Null Detector.

When used with a slotted line, the 1231-P4 functions as an attenuator for the 1231-B when making SWR measurements. The 1231-P4 provides a total of 80 dB of attenuation — 20 dB variable and three additional fixed 20 dB steps.

Specifications

• Source Impedance: 30 kΩ
• Load Impedance: 1 MΩ or greater
• Attenuation Range: 80 dB
• Maximum Input Power: 0.5 W

Links

• Experimenter January 1950 describing Type 1231-P4

Photos

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