50 kW Short-Wave Broadcast Transmitter HFB-7847

NEC Corporation, Nippon Electric Co. Ltd. (Nippon Denki); Tokyo

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  • Year
  • 1984 ?
  • Category
  • Commercial Transmitter (TX not Transceiver)
  • Radiomuseum.org ID
  • 328876

 Technical Specifications

  • Number of Tubes
  • 4
  • Number of Transistors
  • Semiconductors present.
  • Semiconductors
  • Main principle
  • Transmitter
  • Wave bands
  • Short Wave (SW only)
  • Power type and voltage
  • Alternating Current supply (AC) / 3 phase, 400 V & 200 Volt
  • Material
  • Metal case
  • from Radiomuseum.org
  • Model: 50 kW Short-Wave Broadcast Transmitter HFB-7847 - NEC Corporation, Nippon
  • Shape
  • Rack
  • Dimensions (WHD)
  • 4400 x 2200 x 2800 mm / 173.2 x 86.6 x 110.2 inch
  • Notes

  • The NEC, FB-7847, 50 kW Short-Wave Broadcast Transmitter is all solid state except for Four high gain tetrode tubes, one in Modulated Power Amplifier, two in Modulator Amplifier and one in Exciter stage. Output syage is vapor cooled.

    Technical Specifications:

    Rated Carrier Output 50 kW
    Transmitter Output Capability 53 kW
    Frequency Range and Frequency Changing Specified 6 pre-set frequencies within range of 3.2 to 15.6 MHz
    Frequency Change Time Max. 3 minutes
    Modulation system Final stage class B modulation system with simultaneous screen mod
    Audio Frequency Response From 50 to 7,500 Hz. Flat within ±1 dB
    From 30 to 10,000 Hz. Flat within ±1.5 dB
    Audio Frequency Distortion Less than 3% at 95% modulation within a frequency range from 50 to 7,500 Hz
    Noise Level Better than 60 dB. Unweighted for 1,000 Hz at 100% modulation
    Carrier Shift Less than 3% for 100% modulation at 1,000 Hz
    Carrier Frequency Stability ±1 x 10-6
    Spurious Radiation Below 50 mW, complying with CCIR recommendation
    Audio Input Level 0 dBm at 1,000 Hz for 100% modulation
    Output Impedance 50 ohms, unbalanced
    Modulation Capabilities 1,000 Hz at 100% modulation: 20 minutes
    From 50 to 7,500 Hz at 100% modulation: 10 minutes
    Overmodulation: Can withstand a level three times as high as the input level,
    required to achieve 100% modulation at 1,000 Hz three times at each interval of 1 second for 2 seconds duration
    Overall Power Factor More than 90%
    Ambient Temperature From 0° to 45°C
    Cooling System Vapour cooling

     

  • Mentioned in
  • -- Original prospect or advert
  • Author
  • Model page created by Gary Cowans. See "Data change" for further contributors.

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