photo Continental Electronics 420 D DRM The Continental Electronics Type 420D-DRM Transmitters are versatile, state-of-the-art, high-efficiency 500 kW DRM shortwave transmitters capable of being operated in standard amplitude modulation (AM), Controlled Carrier-level Modulation (CCM) or digital streaming in the DRM mode (when used with the optional DRM Encoder/ Exciter).

From a central master control panel or from a remote computer, the 420D-DRM Transmitters may be set up and either preset or automatically tuned to deliver full carrier power at any frequency between 3.9 and 26.1 MHz. If desired, they may also be manually tuned using controls and indicators located on the central master control panel.

The Continental Electronics Type 420D-DRM Transmitters employ some of the most technologically advanced components available today. They include all required switch gear, power supplies, protective circuits, amplifiers, controls, and cooling and peripheral equipment. They are compact in design yet easy to service and maintain. Particular care in the design has been given to operational reliability and efficiency, resulting in transmitters delivering high performance broadcast service with minimum maintenance and down time.

RF Carrier Output Power (A3E) 500 kW on all frequencies through the 3.90 to 26.1 MHZ range
Reduced RF Carrier Output Power (A3E) The Type 420D DRM Transmitter can be operated at any power level between 75 and 500 kW with the controls provided
Power Source 4160 VAC, or 11,000 VAC, 3 phase, three wire, 50/60 Hz. Other voltages on special order. Mains power requirement is 1200 kW with 100% tone modulation condition at 0.95 lagging power factor
Efficiency The overall efficiency of the Type 420D DRM Transmitter measured as an average of ten frequencies over the range of 3.9 - 26.1 MHz at 500 kW carrier power level will not be less than 75% with any depth of modulation. (Lower at lower power levels)
Frequency Range 3.9 - 22 MHz continuous in 100 Hz increments. 5.8-26.1 MHz, optional
Tuning Time An average of 10 typical frequency changes takes less than 30 seconds each
Standing Wave Ratio Rated for 2.0:1 VSWR at full power or any customer selected VSWR below 2:1
RF Output Impedance 300 ohms balanced (Standard); 50 or 75 ohms unbalanced Optional
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
RF Spurious Less than 50 mW. Out of band emissions in compliance with CCIR 328-5
Ambient Temperature Range Indoors: +40 to +111°F (+5 to +45°C)
Outdoors: +14 to +111°F (-10 to +45°C)
Relative Humidity Range 0 to 95% relative humidity, non-condensing
Altitude Up to 6,000 ft. (1,829 m) above sea level
Cooling Water, heat exchanger (supplied), and air cooling
Modes of Emission A3E and DRM, Standard, SSB Optional
Modulation Method High efficiency all-solid-state step modulator using EER for AM/PM Modes
Audio Input Requirements Adjustable from -8 to +10 dBm for 100% AM modulation
Audio Input Impedance 600 ohms, balanced. Other impedances on special order
Audio Response (A3E) +/-1 dB from 50 Hz to 5000 Hz at 70% modulation or modulation level. +1/-1.5 dB, 5000 - 7500 Hz
Audio Harmonic Distortion (A3E) Less than 3.5% at 50-90% modulation from 50 to 7500 Hz; less than 4.5% at 90-100%
Carrier Noise -56 dB, unweighted, referenced to 100% modulation with a 1 kHz tone
Controlled Carrier Level Modulation (CCM) The Type 420D 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
RF Output Power (DRM) 250 kW RMS, 2000 kW PEP with 9 dB Crest Factor
DRM: 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
DRM Modes All DRM 9 kHz and 10 kHz bandwidth modes are supported
MER (Modulation Error Rate) -30 dB, or better
SSB Option
RF Output Power (H3E and R3E) 1000 kW PEP Two-Tone
High Efficiency H3E and R3E (LSB, USB and ISB) using EER (Envelope Elimination and Recovery)
Intermodulation Distortion (H3E & R3E) At least -35 dB relative to either tone of a two-tone test signal
Carrier Reduction (H3E & R3E) -6 dB to -24 dB relative to full carrier or full Carrier suppression
Specifications may change without notice

RF stages AF stages and modulator
Number Type Number Type
1 4CM400,000A/AG or 4CM500,000G
or TH558 or TH576 or RS 2078 or BEL550,000CX

1 3CW20,000A7


ITU Country
ITU Country