BG7TBL GPSDO, measured the EFC voltage compared to freq. drift.

[Wim13]

I wanted to know how the EFC voltage on Trimble OCXO in the BG7TBL GPSDO with display was behaving compared to the freq. drift.
Because i noticed some frequentie jumps.

It seems the Trimble OCXO type 73090 has a very sensitive EFC, a few Hz/Volt

I used the HP3457A for the voltage measurment, resolution 1 uVolt, and Timelab for the freq drift.

Measure time 1 hour.

Fig 1, the voltage plot
Fig 2, the Timelab plot
Fig 3, just for info the Trimble OCXO
Fig 4, cold start EFC voltage
Fig 5, cold zoom EFC detail 1
Fig 6, cold zoom EFC detail 2

[Wim13]

I also measured the temp of the Trimble OCXO, as i can only measure on the case at the top of the OCXO case.
So the sensor is touched to the metal on the top, and the metal box of the BG7TBL GPSDO is closed.

i made a little connector on the back of the box, for the sensor, so there is no extra air flow.

The final temp is 50,3 celsius, it takes two hours before it reaches it final.

Next i tested what happened if i touch the outher GPSDO box ( so not the OcXO), for a few moments.

The temp inside drops...see plot: