As I wrote upthread, last week's TEA is another counter. Now, I'm up to three, not counting (pun most intended) the ones in various multimeters et c. And I'm deliberately avoiding the FeelTech function generator input, since it does not count (pun...) due to it being the shittiest of them all (it is beaten by the 5221B that's entirely untouched since manufacture bar a PSU repair and, still, dead on.). The last addendum, in true time-nut fashion, is a TTi TF830, and it's got the most digits of them all.
Here, it's displaying my local 10MHz reference over 10 seconds measuring period, which by the way is exactly where it overflows in 10s mode (if I shorten the measurement period by one magnitude to 1s, the amount of digits precision lessens so as to accomodate the full 10MHz).
First, locked to the same source:
As expected, clean sheet, with all zeroes and an overflow indicator; This of course is just a basic functionality test since it's comparing an apple to itself.
Then, less reference input:
172 Hz off is 17ppm, which I think is a tad high. I need to let it warm up thoroughly and get to tweaking it. I think I can reduce the error by one magnitude, but the "cal" trim pot (visible just to the right of the reference input on the first picture) is not very coöperative, it seems to jump between -10ppm and +10ppm with no way to rest in the middle..