Nautel XR6 – 6kW AM Transmitter (Single Phase)

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The XR6 is purposely designed for demanding AM broadcast applications that require reserve power. This extra power overcomes antenna system losses such as those encountered in complex directional arrays. It allows aggressive audio processing and high levels of asymetrical modulation to produce more sideband energy and a louder signal. Extra power also makes it possible to maintain full power AM transmission while transmitting a digital signal or simultaneous phase-coded data.

The XR6’s graphic user interface and soft-keys give you simple menu control of operating modes. Six power level selections are continuously adjustable over the full range using raise/lower commands. Programmable system profiles let you define schedules for changes to power and modulation settings. An LED diagnostic status flow diagram continually monitors the system and an advanced control, alarm and 128 event time stamped logging system allows service personnel to easily identify problems.

The XR6 has been specifically designed to support the digital transmission formats now available and being developed for use on existing AM channels. Nautels employs an ultra linear extended band filter that maintains an envelope bandwidth of 40kHz. The RF drive design optimises IPM to ensure minimal phase error. This provides superior spectral performance when transmitting a digitally encoded signal using digital modulation techniques such as HD Radio and DRM. The XR6 transmitters’ digital performance is outstanding, even with the limited bandpass performace of real-world antenna systems. This combination of compatibility, performance and flexibility makes the XR6 an excellent choice for digital broadcasters.


  • RF power – 6kW (rated) 7.5kW (capable)
  • 145% positive peak modulation at rated power
  • Dual DDs exciters with automatic changeover
  • 1.5:1 VSWR at rated power, 100% modulation
  • Plug and play integration with Nautel’s NE IBOC AM HD Radio Signal generator
  • Built-in preset schedular allows for six preset power levels
  • Programmable user interface facilities custom profiles for each preset
  • Second spare power module provides full main/standby feature
  • Dimensions 58.4cm W x 184cm H x 80.5cm D

Technical Specification

Technical Specification

Transmitter Type

  • Medium wave, 100% solid state


  • Eight broadband RF amplifiers and four modulators mounted in a plug-in RF Module
  • Dual DDS exciters and modulation encoders.
  • Full automatic changeover
  • Second redundant spare module with full automatic changeover (optional)

RF Output Power

  • Maximum: XR6 – 7.5 kW

Max Average Power

  • XR6 – 9 kW
    (6 kW + 100% modulation)


  • XR6 – 50 W to 7.5 kW

RF Output Connection

  • 7/8″ or 1 5/8″standard

RF Output Impedance

  • 50 ohms, unbalanced


  • 83% typical


  • XR6 – 1,000 peak reflected watts 1.5:1 VSWR at 6 kW, 100% modulation

Frequency Range

  • 531 kHz to 1,710 kHz. Supplied, tuned and tested to one frequency as specified

Frequency Stability

  • ±2 ppm over temperature range.
  • External GPS for increased stability

Modulation Type

  • Nautel Wideband Interphase Pulse Duration Modulator

Modulation Capability

  • 155% positive peak modulation at 5 kW
  • 145% positive peak modulation at 6 kW
  • 120% positive peak modulation at 7.5 kW

Spurious and Harmonic

  • Exceeds FCC, IC and ITU requirements 80 dB relative to carrier


  • 200 to 260 V ac, 1 phase
  • 50 Hz or 60 Hz to customer specifications

Power Supply Variation

  • ±10% voltage, 47 Hz to 63 Hz

Power Consumption

  • 6 kW typical at 5 kW, 0% modulation
  • 9 kW typical at 5 kW, 100% modulation
  • 7.2 kW typical at 6 kW, 0% modulation
  • 10.8 kW typical at 6 kW, 100% modulation

Power Factor

  • 0.85 typical, 1 phase

Temperature Range

  • 0°C to +50°C
  • Derate 3°C per 500 m above sea level (2°C per 1,000 ft)

Humidity Range

  • 0% to 95% non-condensing


  • 0 m to 3,000 m (0 ft to 10,000 ft)

Cooling Air Requirements

  • 340 m3/hr (200 CFM)


  • 184 cm H x 58.4 cm W x 80.5 cm D
  • (72.5” H x 23” W x 31.7” D)


  • XR3/XR6 – 1 Ph – 223 kg (493 lbs)

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