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418G-DRM 100 kW Shortwave Broadcast Transmitter  
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Specifications-- 418G-DRM 100 kW Shortwave Broadcast Transmitter

ELECTRICAL  
AUDIO
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/-1.5 dB from 50 Hz to 7500 Hz at 70% modulation
 
Audio Harmonic Distortion (A3E)
Less than 3.0% at 50-90% modulation from 50 to 7500 Hz
 
Carrier Noise
-56 dB, unweighted, referenced to 100% modulation with a 1 kHz tone
 
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
 
DRM
RF Output Power (DRM)
50 kW RMS, 400 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)
200 kW PEP Two-Tone
 
High Efficiency
H3E and R3E (LSB, USB and ISB) using EER (Envelope Elimination and Restoration)
 
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
 
RF Carrier Output Power (A3E)
100 kW (400 kW PEP) on all frequencies through the 3.90 to 22 MHZ range
 
Reduced RF Carrier Output Power (A3E)
25 kW - 100 kW
 
Power Source
Customer specified: 360-480 VAC, 50/60 Hz, 3-phase, other voltages available on request
 
RF
Efficiency
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)
 
Frequency Range
3.9 - 22 MHz continuous in 100 Hz increments. 3.9?26.1 MHz, optional, 2.3 ? 16 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
 
ENVIRONMENT
Ambient Temperature Range
(+5 to +45 degrees C)
Outdoors: +14 to +111 degrees F
(-10 to +45 degrees 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