[time-nuts] Calbrating the Lucent RFG-M-XO Efratom 10MHz OCXO Oscillator w/ EFC

Stanley Reynolds stanley_reynolds at yahoo.com
Mon Jun 16 19:52:18 EDT 2008

I do not have the GPS model or the rubidium model this unit goes with.
Supply your 10Mhz reference to J2
Monitor VCC to  OCXO 4.25 volts is a Default state varies from there to about -.57 volts, the movement of the voltage will tell you what the ECC processor is doing.

With a 2.7K pull up resistor from +5 volts pin 1 of J5 will place the unit in standby. Another pull up on J5 pin 3 will cause the unit to light the fault light it will stay on without the pullup while it is calibrating.
Both pin 1 and 3 high at power up places the unit in calibrate mode.
I'm not sure what makes it do what, the steps and order, but have got it to calibrate to two different standards. That is to save a diferent ECC voltage thru a power cycle.
By placing a standard on the 10 MHz input and taping the 10 MHz at the OCXO feeding this into my Austron 2100F I'm able to track a loran station, swapping the phase corrected output from the 2100 for the standard after a few hours I'm able to close the loop. It has been tracking this way for a few hours, I have no idea if it is stable yet. Also not sure it will stay in calibrate mode with neither pin pulled high. When I first switched to the phase corrected output was at E13 but wasn't long a few minutes and I was back in the E10 region. The VCC voltage is moving very slowly so I have hope it will stay stable.


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