RF Enables Communications

 
419G/420C 300/500kW Shortwave Broadcast Transmitter  
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Specifications-- 419G/420C Shortwave Broadcast Transmitter

Electrical

 

Audio


Modes of Emission
A3E or H3E and R3E
 
Modulation Method
High efficiency solid state step modulator
 
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

 
Controlled Carrier Level Modulation (CCM)
The Type 419G/420C Transmitter has the capability of operating in a controlled carrier modulation mode.  This is an amplitude modulation technique that scales the amplitude of the carrier to the percentage of modulation. In typical modulation applications, the carrier can be reduced as much as 6 dB below the rated value.  This feature can be a major cost saving to the user
 
Single Sideband Operation (H3E and R3E) (OPTIONAL)
Single Sideband (SSB) operation is provided using a phase-amplitude method of generating the single sideband signal.  This provides high quality SSB operation with greater efficiencies than a linear amplifier can provide.
 
RF Spurious Noise
Less than 50 MW.  Out of band emissions in compliance with CCIR 328-5
 

RF Harmonic Outputs

Less than 50 MW
 
Audio Response (A3E)
+/-1 dB from 50 Hz to 7,500 Hz at 70% modulation or any lower modulation level
 
Audio Response (H3E & R3E)
+/-0.5 dB from 100 to 4,500 Hz at any level up to the average power capability
 
 
Audio Harmonic Distortion (A3E)
Less than 3.5% at 90% modulation from 50 to 7500 Hz
 
Audio Harmonic Distortion (H3E & R3E)
Less than 3.5% at full average power capability from 100 to 4500 Hz
 
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 two-tone PEP output, adjustable in 3 dB steps.
 
Audio Input Requirements
Adjustable from -8 to +10 dBm for 100% modulation
 
Audio Input Impedance
600 ohms or 10K ohms, balanced
 
Carrier Level Shift (A3E)
Less than or equal to +/-3% shift at 100% tone modulation with 1 kHz sinewave exclusive of powerline variations
 
Carrier Noise
-56 dB unweighted referenced to 100% modulation with a 1 kHz tone
 
RF Carrier Output Power (A3E)

(420C-500 kW/419G-300 kW) on all frequencies through the 3.90 to 26.1 MHz range

 
Reduced RF Carrier Output Power (A3E)

The Type 419G/420C Transmitter can be operated at any power level between 45/75 (with slight reduction in overall efficiency) and 300/500 kW with the controls provided

 
RF Output Power (H3E and R3E)

420C - 1000 kW PEP Two-Tone, 1500 kW PEP Program Modulation; 419G - 600 kW PEP Two-Tone, 800 kW PEP Program Modulation

 
Frequency Range

3.90 to 26.1 MHz continuous in 100 Hz increments

 
Tuning Time
An average of 10 typical frequency changes take less than 25 seconds each
 
Standing Wave Ratio
2.0:1 VSWR at full power
 
RF Output Impedance
50 or 75 ohms unbalanced; 300 ohms balanced
 
 
Environment
Ambient Temperature Range
Indoors: +40 to +111 degrees F (+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
 
Power Source
4160 Vac, or 11,000 Vac, 3 phase, three wire, 50/60 Hz.  Other voltages may be accommodated on special order.  Main power requirement is 650/1200 kW with a 100% tone modulation condition and equal to or greater than 0.95 lagging power factor
 
Efficiency

The overall efficiency of the Type 419G/420C Transmitter measured as an average of ten frequencies over the range of 3.9 - 26.1 MHz at 300/500 kW carrier power level will not be less than 71/73% with any depth of modulation.  Overall efficiency of 73/75% is expected during cool weather conditions and at the lower RF frequencies