RF Technology ECLIPSE UHF Data Transmitter Repeater 30W exciter 450MHz

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RF Technology ECLIPSE UHF Data Transmitter Repeater 30W exciter 450MHz :
$125.00

This is a 1RU 19in rack mountable NBFM UHF synthesized transmitter, made by RF Technology Australia under the Eclipse model name.
This item does not include a receiver as can be seen the front panel speaker and volume control were never wired up.
This was delivered as an exciter module with the DMTX digital modulation option, type 30/9114/0001 for data of FSK or NRZ at up to 4800 bps.
TTL or RS432 inputs are used for the data input and analog inputs of 10K Ohms and 600 Ohms line impedance are available along with other signals through the DB-37 connector on the rear panel.
Programming is done via a DB-9 on the front panel using a serial port on an external computer. All CTCSS / PL tone are available by program.

Operates off 13.5Vdc.The freq coverage for the 500B is 450 to 520MHz, with only a tweak of the VCO required.
The power amplifier is a SS broadband module mounted on a external heatsink on the rear and is specified as delivering from 10 to 30Watts continuous duty up to 40C. The directional coupler included will reduce power and set an alarm function if VSWR exceeds preset limits while a thermistor on the heatsink is provided as fault detector in case of excessive temp rise and reduces power to zero at 60C (140F). The designed freq range does not include any frequencies below the commercial UHF band and the manufacturer's RSS does not allow programming outside this range, despite several emails promising a fix for this I was never given any answer as to how to program it for the ham band. I can program one freq for the prospective buyer but remember the input is applied to a digital modulator and will not modulate properly with analog input. To revert to analog I believe one would normally remove the DMTX board that sits atop the crystal reference oscillator, a 1ppm reference good from 0-60C, but the method of construction makes it necessary to slide the exciter board out the front after removing the front panel to access the nuts that affix the DMTX board (see last photo). Adding a slot on the internal rail would have facilitated this but I guess the manufacturer never intended for these to be downgraded in the field.The modular approach makes repair of this equipment easy, something that most manufacturers have neglected.
The freq synthesizer uses a non-volatile memory in the CPU to retain up to 100 channels which can be selected by BCD command.
I tested the exciter for its frequency programmability and the only thing I noted was the reference is slightly off but no adjustment was made due to the presence of the DMTX board.
The PA delivered stated power at 450.000 MHz and data modulation can be observed but other than this I have no way to test further. I am certain this will work for its intended design purpose (digital modulation) and I cannot guarantee anything beyond that.
Includes top cover and manufacturers manual for T500 module on CD.