50 Year old Ovenized Oscillator vs GPSDO

[Ground_Loop]

I noticed that switching between internal and external GPSDO oscillators on my Systron Donner frequency counter yielded nearly identical readings throughout the range. So, I hooked up both oscillators in XY to see just how close the vintage is to the modern reference.  Shown in the video linked below.  Boat anchors ain't so bad.

https://youtu.be/6cYQDcuQsqk

[factory]

In the picture you are using the self "test" function, this only checks the functionality of the counter, if you feed in any frequency to the external oscillator input, it will still show the same readings.
Maybe you did connect the GPSDO to the counter input, but didn't take a picture, this would show how close they are, use the slowest timebase setting for this.

David

[Ground_Loop]

In the picture you are using the self "test" function, this only checks the functionality of the counter, if you feed in any frequency to the external oscillator input, it will still show the same readings.
Maybe you did connect the GPSDO to the counter input, but didn't take a picture, this would show how close they are, use the slowest timebase setting for this.

David

The picture just illustrates the two instruments not their oscillator performance.  The real evidence is in the linked video.  But yes, the counter is in the test position.