The NDB Transmitters (JTM-30C and JTM-50C) are available as Single and Dual Transmitters. As Dual Transmitter they have two complete transmit chains with fault detection/reporting and automatic changeover.
The JTM-30C and JTM-50C versions are built upon on a totally new concept for NDB transmitters utilizing digital Exciters and PC controls. The transmitters have, among other facilities, following main features:
The carrier frequency may be set in steps of 1 Hz from 190 kHz to 2MHz
Frequency generation by Direct Digital Synthesis featuring high linearity and stability of carrier and modulation, low noise and excellent frequency accuracy
The Exciter provides full power control of the carrier
The transmitters operate with N0N/A2A or N0N/A3A emission.
MSK modulation available as an option
A Timer function enables four different Morse sequences:
Continuous transmission of Morse keying, with automatic keying sequence repetition
Transmit one time Morse keying sequence only
Transmit repeated Morse keying sequences during a specified interval
Transmit the Morse keying sequence once for every specified interval
All versions of transmitters are equipped with functions for monitoring the transmitter in operation, carrier level, modulation and failure conditions
Flexible control and monitoring from an attached PC via RS485, or from any remotely connected Internet PC via locally dedicated NDB PC
Through the RS-485 remote control interface all parameters above may be monitored and/or controlled
The RS-485 remote control interface also provides an event log that records all system events, such as restart, parameter changes and error events
The NDB Transmitters have built-in non-volatile memory sufficient for storage of the entire transmitter configuration enabling stand-alone un-attended operation. Saving the configuration in solid-state memory is controlled via the PC interface
In addition to the PC interface, the NDB Transmitters also include Remote Control Unit interface that can be attached via a separate galvanic isolated port to provide simple operation of the transmitter from remote location(s). The Remote Control Units may be chained to more than one location up to 500 m between Transmitter and Remote Control(s)
JTM-30C may be delivered with 100W RF power output power from the RF Amplifier or 250 WPEP.
JTM-50C may be delivered with 500W RF power output power from the RF Amplifier or 1000 WPEP.