Solid State AM Transmitter - AM Broadcast Transmitters

Shortwave Transmitters

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NTCSWTX HF 10000, 10KW
Solid State Shortwave Transmitter

Synthesized Exciter -The RF source of the transmitter is a front panel controlled unit which serves as the frequency source for the transmitter when operating the transmitter as an AM analog broadcast transmitter. The normal frequency coverage is from 2 to 10MHz. As an option, this drawer can produce adequate TTL drive from 2 to l8 MHz. All circuitry is solid state.

Controller — The NTCSWTX HF-l0,000 utilizes a controller that permits (5) power level presets, (4) times fault recycling and (4) overload circuits. These overloads relate to protective levels for maximum allowable output VSWR, DC over current, DC over voltage and excessive RF output current. The controller chassis contains a PDM generator which operates at 200KHz and has a frequency response of ; 0.5db from 20Hz to 50KHz.

2KW RF Amplifiers — The NTCSWTX HF l0,000, contains (6) 2KW broadband solid state RF amplifiers. All amplifiers are broadband and require no tuning over 2 to l0MHz. As an option, these amplifiers can be supplied to produce rated output from 2 to l8 MHz. The amplifier drawer contains (4) 500 watt broadband, solid state amplifiers which are combined to produce 2KW output. These circuits are operated in Class E and have an RF efficiency of 93 to 97%

12KW Solid State Combiner— This combiner accepts the output of each 2KW amplifier and combines all six amplifiers by utilizing conventional solid state combiner techniques. The output impedance often combined six amplifiers is relatively low. This impedance is transformed to 50 ohms by appropriate front panel adjustment of (3) calibrated counter dials which describe the settings of three variable vacuum capacitors. These counter dials are calibrated so that the operator can change frequency by simply setting these controls to their desired positions.

Antenna Tuning Unit- The output of the combiner is fed to a fiill "T" network. The front panel control of this chassis utilizes calibrated counter dials which are used to permit the operator to change to the desired operating frequency within minutes. These controls have the capacity of transferring rated power output to a mismatch as high as 3: l.

DRM Compatible The NTCSWTX HF 10,000 has been designed with utilization of DRM (Digital Radio Model in mind. This has required a PDM source of 200KHz, a PDM frequency response of 20Hz to 50Khz, an lM distortion of less than -55 db and RF tuned circuits with essentially zero group delay. Thus, customer need only add DRM exciter to achieve excellent DRM digital stereo performance.

High Efficiency, Low Distortion PDM - The NTCSWTX HF 10,000 utilizes modern Pulse Duration Modulation which has a frequency response of 2OHz to 50KHz. it's efficiency is 95% at all audio frequencies at 95% modulation levels. The combination of this high modulator efficiency and the high RF efficiency of 93 to 97% results in an AC efficiency of 85 %.

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