The type 418G-DRM Shortwave Transmitter -100kW is designed to provide high performance, optimum efficiency, and long-term reliability in shortwave broadcast bands.


AM, CCM or Digital Streaming Modes

High Efficiency

Field Tested

Longest Life Available

  • Operate in standard amplitude modulation (AM) mode with Controlled Carrier-level Modulation (CCM), or digital streaming in the DRM mode (when used with the optional DRM Encoder/ Exciter)
  • 70 – 74 % overall efficiency on average
  • Field tested and proven DRM transmitter system
  • 418G-DRM Shortwave Transmitter -100 kW is direct descendant of successful line of Continental 100 kW broadcast transmitters; employs same highly refined and reliable RF components
  • RF amplifier tube is the 4CV100,000C tetrode, is the longest life, lowest cost high-power tube available
  • Up to 280 preset frequency channels achieved within 30 seconds between two frequencies


  • Computer-Assisted Touch Screen Control System and front panel button operation
  • TCP/IP Based Remote Control System allows unattended operation enabling complete control from off-site
  • Standard Frequency Range 3.9 – 22 MHz; options of 3.9-26.1 MHz and 2.3-16 MHz
  • Exclusive CCM (Controlled-Carrier level Modulation) allows carrier reduction from 0-6 dB in 1dB steps
  • Self-Contained Water System for Primary Loop Cooling can be used with external heat exchanger or facility water
  • High-Efficiency Solid State Modulator and High Voltage Power Supplies offer low-stored energy protection without requiring a crowbar
  • Dual Fan, External Heat Exchanger with Coated Coils and Epoxy Coated Enclosure for Corrosion Resistance
  • High-Speed Arc Sensors In All Critical RF Component Areas


RF Carrier Output
Power (A3E):

100 kW (400 kW PEP) on all frequencies through the 3.90 to 22 MHZ range
Modes of Emission:

A3E and DRM, Standard, SSB Optional

The overall efficiency of the Type 418G DRM Transmitter measured as an average of ten
frequencies over the range of 3.9 - 26.1 MHz at 100 kW carrier power level will not be less than
67% with any depth of modulation. (Lower at lower power levels)
RF Output Power (DRM):

50 kW RMS, 400 kW PEP with 9 dB Crest Factor
Ambient Temperature Range:

(+5 to +45 degrees C)
Outdoors: +14 to +111 degrees F
(-10 to +45 degrees C)
RF Output Power:

(H3E and R3E)
200 kW PEP Two-Tone
Reduced RF Carrier
Output Power (A3E):

25 kW - 100 kW
Modulation Method:

High efficiency all-solid-state step modulator using EER for AM/PM Modes
Frequency Range:

3.9 - 22 MHz continuous in 100 Hz increments. 3.9?26.1 MHz, optional, 2.3 ? 16 MHz, optional

Meets all IEC PAS62272-1 & ETSI REF.ES 201 980 V.1.2.1 2002-07 specifications
See the exciter brochure for a full list of features. DMOD3 DRM Exciter is totally integrated into
the transmitter
Relative Humidity Range:

0 to 95% relative humidity, non-condensing Altitude Up to 6,000 ft. (1,829 m) above sea level
High Efficiency:

H3E and R3E (LSB, USB and ISB) using EER (Envelope Elimination and Restoration)
Power Source:

Customer specified: 360-480 VAC, 50/60 Hz, 3-phase, other voltages available on request
Audio Input Requirements:

Adjustable from -8 to +10 dBm for 100% AM modulation
Tuning Time:

An average of 10 typical frequency changes takes less than 30 seconds each
DRM Modes:

All DRM 9 kHz and 10 kHz bandwidth modes are supported

Water, heat exchanger (supplied), and air cooling
Intermodulation Distortion (H3E & R3E):

At least -35 dB relative to either tone of a two-tone test signal
Audio Input Impedance:

600 ohms, balanced. Other impedances on special order
Standing Wave Ratio:

Rated for 2.0:1 VSWR at full power or any customer selected VSWR below 2:1
MER (Modulation Error Rate):

-30 dB, or better
Carrier Reduction (H3E & R3E):

-6 dB to -24 dB relative to full carrier or full Carrier suppression
Audio Response (A3E):

+1/-1.5 dB from 50 Hz to 7500 Hz at 70% modulation
RF Output Impedance:

300 ohms balanced (Standard);
50 or 75 ohms unbalanced Optional
Audio Harmonic Distortion (A3E):

Less than 3.0% at 50-90% modulation from 50 to 7500 Hz
Carrier Level Shift (A3E):

Less than or equal to +/-3% shift at 100% tone modulation with 1 kHz sine wave exclusive of power line variations
Carrier Noise:

-56 dB, unweighted, referenced to 100% modulation with a 1 kHz tone
RF Spurious:

Less than 50 mW. Out of band emissions in compliance with CCIR 328-5
Controlled Carrier Level Modulation (CCM):

The Type 418G DRM Transmitter has the capability of operating with variable carrier power. This
technique scales the amplitude of the carrier to the percentage of modulation. The carrier can be
reduced as much as 6 dB below the rated value without audio distortion and can be a major cost
saving to the user
Modulation Capability:

100% sinusoidal modulation at frequencies from 50 to 7,500 Hz, for ten (10) minutes per hour. Up to
70% modulation on a continuous basis