Alfred Electronics 650 Sweep Oscillator 2-4 GHz w/ 652CK Plug-In Benchtop RF

Alfred Electronics 650 Sweep Oscillator 2-4 GHz w/ 652CK Plug-In Benchtop RF

The Alfred Electronics 650 is a vintage benchtop sweep oscillator mainframe designed to accept interchangeable oscillator plug-ins covering different microwave frequency bands. This unit is equipped with the Alfred 652CK oscillator plug-in, covering 2–4 GHz, making it a complete RF sweep signal source in that range. The 650 mainframe provides sweep control, modulation, and marker functions, while the plug-in supplies the actual RF output — a modular architecture common in precision RF lab instruments of this era.

Specifications & What's Included

• Mainframe: Alfred Electronics Model 650 Sweep Oscillator
• Plug-in installed: Alfred 652CK Oscillator Plug-In
• Plug-in frequency range: 2–4 GHz
• RF Output: Leveled and Unleveled outputs on plug-in front panel
• Sweep modes: Manual Sweep, Single, Retrace, Free Run, External trigger
• Frequency display: Dual analog dial scales (F1/F2) with M1/M2 marker pointers
• Frequency controls: F1, F2 tuning knobs; M1, M2 marker amplitude knobs
• Modulation: AM Off, Square Wave, FM modulation modes
• Sweep time control: Variable, with internal/external trigger selection
• External RF Sampler: Sens and Input connectors on plug-in panel
• Rear panel: Remote Power Level binding posts, Remote Frequency control, Blanking Relay Contact Output (1A max), Frequency Stabilizing Input
• Power requirements: 115V AC / 3A, or 230V AC / 1.5A (selectable)
• Form factor: Benchtop, two-section stacked cabinet with carrying handles

Applications

Sweep oscillators like the Alfred 650 were standard RF lab instruments from the 1960s and early 1970s, used in microwave component characterization, antenna testing, and swept-frequency network analysis. The plug-in architecture allowed a single mainframe to cover multiple bands by swapping modules — a practical design for production test and R&D labs working across the microwave spectrum. The 2–4 GHz band covered by the 652CK plug-in falls in the S-band and low C-band range, relevant to radar, satellite, and early microwave communications work. Today these instruments are primarily of interest to vintage test equipment collectors, restoration enthusiasts, ham radio operators, and educational institutions with an interest in classic microwave lab techniques. The Alfred Electronics brand was a U.S. manufacturer active in the mid-twentieth century producing RF and microwave signal sources; their instruments are less commonly found on the surplus market than comparable HP or Wavetek units, which adds to their collector appeal.