(General coverage version of the KWM-380)

The 451S-1 is a professional single sideband (SSB) communications receiver that offers reception of upper and lower sideband, CW, AM, or FSK signals over the frequency range of 0.2 to 30 MHz. The unit is of solid-state design and contained in an attractive desk-top package with built-in power supply and speaker. Single knob tuning cover the entire frequency range without bandswitching and a high resolution synthesizer with microprocessor control provides four tuning rates down to 10 Hz increments.

High dynamic range along with an operator selectable 20 dB rf input attenuator and passband tuning minimize the effect of adjacent channel interference.

A built-in meter monitors signal strength or line output level. Two operating frequency registers allow rapid change between any two previously selected frequencies. A rear panel connector provides input for an optional keypad to select, store, and recall frequencies.

The 451S-1 operates from 115/230 V 50/60 Hz ac or +13/5 V dc.


  • Fully Synthesized in 10 Hz steps
  • General Coverage — 0.2 to 30 MHz
  • Internal Microprocessor Control
  • Solid-State Modular Construction
  • SSB/CW and AM Modes
  • Passband Tuning
  • Built-in AC/DC Power Supply and Speaker
  • Digital Frequency Readout


  • AC-3801 Noise Blanker
  • AC-3805 Keypad Assembly
  • AC-3811 140-Hz CW Filter
  • AC-3812 1.7 kHz SSB/RTTY Filter
  • AC-3814 3 kHz Wide-Band SSB Filter


  • A rack mount, headphones and dc power cord are available.