Collins 51S-1 and 55G Preselector

$3,495.95

Collins 51S-1 Collectors Quality Pristine Condition

 

51S-1 SPECIFICATIONS

  • Frequency range: 0.2 to 30.0 megahertz in thirty 1-megahertz bands continuous coverage. 
  • Modes: Upper sideband, lower sideband, AM or CW. 
  • Power consumption: 125 watts. 
  • Type of service: Fixed station attended with provision for remote control of rf gain. 
  • Rf input impedance: 50 ohms, unbalanced. 
  • 500-kHz if. output at J9... 50 mv minimum into 50-ohm load with 0.5-uv input signal. 
  • Matching speaker impedance. 4 or 600 ohms. 
  • Balanced line out impedance. 600 ohms balanced, center-tap ground reference or floating. (For 51S-1B, 150 ohms floating.)
  • Matching phone patch impedance (local): 500 to 600 ohms.
  • Frequency stability: During temperature change from 0 to +50 øC, after 20 minutes warmup,audio output frequency will not vary more than +/-885 Hz for carrier frequencies from 2 to 7 MHz. From 7 MHz to 30 MHz, stability varies from 36 PPM +/-400 Hz at 7.00 MHz (652 Hz) to 27 PPM +/-400 Hz at 30 MHz (1210 Hz). For +/-10% line voltage variation, frequency varies not more than + 100 Hz. 
  • Calibration accuracy: When zeroed to nearest 100 kHz calibration point, the frequency will be within +400 Hz. 
  • Dial backlash: Not more than 150 Hz. 
  • Audio-frequency response AM. 100 to 2500 Hz +/-6 db (line channel).
  • 200 to 2500 Hz +/-6 db (local channel). 
  • SSB (high-frequency limit determined by filter
  • bandwidth): 350 to 3050 Hz +/-3.5 db (line channel).
  • 350 to 3050 Hz +/-3.5 db (local channel). 
  • Audio output distortion (SSB test signal 100-microvolt input, 1.0-watt local output, 1-mv (0 dbm) line output)
  • Local: Not more than 10 percent. 
  • Receiver sensitivity (nominal)
  • AM........................   3.0 microvolts for not less than 10-db signal
  •                                + noise/noise (2 to 30 MHz).
  •  
  •                                15.0 microvolts for not less than 10-db
  •                                signal + noise/noise (0.5 to 2 MHz).
  •  
  •                                20.0 microvolts for not less than 10-db
  •                                signal + noise/noise (0.2 to 0.5 MHz).
  •  
  •                                With 55G-1 Preselector, 5.0 microvolts for
  •                                not less than 10-db signal + noise/noise
  •                                (0.2 to 2.0 MHz).
  •  
  •   SSB and CW................   0.6 microvolt for not less than 10-db carrier
  •                                on carrier off (2 to 30 MHz).
  •  
  •                                3.0 microvolts for not less than 10-db
  •                                carrier on carrier off (0.5 to 2.0 MHz).
  •  
  •                                4.0 microvolts for not less than 10-db
  •                                carrier on carrier off (0.2 to 0,5 MHz),
  •  
  •                                With 55G-1 Preselector, 1,0 microvolt for
  •                                not less than 10-db carrier on carrier off
  •                                (0.2 to 2,0 MHz).
  •  
  • Selectivity
  •  
  •   CW (at 6 db points).......   800 hertz bandwidth, nominal. (650 Hz
  •                                minimum, 950 Hz maximum, 300-Hz maximum
  •                                bandwidth optional),
  •  
  •   SSB (at 3.5db points).....   2.75 kilohertz bandwidth (2.4 kHz  bandwidth
  •                                optional),
  •  
  •   AM (at 6 db points).......   5.0 kilohertz bandwidth minimum,
  •  
  •     (at 60 db points).......   22,0 kilohertz per second bandwidth maximum.
  •  
  • Spurious responses (above 2 MHz)
  •  
  • Internal spurious signals...   Less than one microvolt equivalent signal.
  •  
  • Other spurious signals......   Not less than 70 db down, except from 4.8
  •                                to 5.2 MHz, not less than 40 db down.
  •  
  • Image response..............   Not less than 50 db down from 2 to 25 MHz;
  •                                not less than 40 db down from 25 to 30 MHz;
  •                                referenced to midband.
  •  
  • Size:Cabinet version: 7-3/4 in. high by 14-3/4 in. wide by 14 in. deep, Rack-mounted version: 8-3/4 in. high by 19 in. wide by 15 in. deep.
  • Weight:  28 pounds

The Collins 55G-1 LF/MF preselector was designed for the 51S-1. It provides enhanced reception in the 200 kHz to 2 MHz range and features a 4 ohm 5x7 inch speaker. It features a three position band switch:  200-600, 600-2000 kHz and by-pass. Requires 115/230 VAC or 28 VDC. 10 x 7.75 x 8 inches 6.5 Lbs.