The Monitor Sensors 630m Transverter enables any Amateur Radio Station, equipped with a conventional HF transceiver, immediate, all mode, access to the new 472-479 kHz, 630m band. The receiver design incorporates a 7 pole Chebyshev filter, 7kHz wide roofing filter and a 5 pole Chebyshev filter in cascade before the double balanced, commutating mixer, fed by an ultra stable, temperature compensated, extremely low phase noise, MEMS local oscillator. The mixer is followed
by a Chebychev band pass filter into an ultra linear, low noise, current feedback, IF amplifier. A CW signal at -130dBm is readable at the output and yet the onset of compression is not reached until +11dBm. A front end 20dB attenuator can be switched in for even higher signal handling. Overall receiver gain is set to +6dB, or -14dBm with the attenuator active.
The transmitter input circuit incorporates a 0-14 dB switched step attenuator to prevent over driving. The same mixer and local oscillator are used on the transmit side. The PA uses 6 rugged lateral FETs in class AB push-pull to easily achieve the 50 watts rated output. Lateral FETs are inherently linear and temperature stable. The transmitter can be run at full power, indefinitely, into a short or open circuit without any damage to the FETs. Transmit-receive switching is automatic with user selectable VOX delay. Alternatively the PTT line may be used.
The Transverter employs extensive and accurate metering. Power input and output, SWR, Frequency, Attenuation in use, Temperature, Supply Voltage, Current and Resistance are displayed. Transmission is inhibited if frequencies outside the 472-479 kHz band are detected. A tuning screen may be selected which displays SWR in digital and graphical form for easy antenna adjustment. The menu system is self explanatory and users report no manual is needed, although one is supplied. A USB socket is provided for future code upgrades (free of charge) from the Monitor Sensors web site. The Transverter has been designed for the best possible protection against accidental mishaps. It will survive reverse polarity supply and the injection of 100 watts of HF into any of its ports whether in transmit or receive mode. If supply current exceeds 20 Amps, the supply is cut in 2 microseconds. This electronic breaker can be reset by simply switching off and on again. The transmitter will shut down in the unlikely event that the internal heat sink reaches 100°C. The cooling fan is under the
proportional control of the microcomputer and begins operation above 35°C. Any unusual operation will cause the screen to turn red and an appropriate warning will be displayed.
RF frequency range 472 to 479 kHz
IF frequency range 1802 to 1809 kHz (others available in the 160m band)
Transmission modes CW, SSB, WSPR, and all other data modes
Output Power 50 Watts Continuous, 100% duty cycle @13.8V supply
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