|Classic "lots of zeros" picture of the REF-0 10MHz output.|
Does this shot have much meaning? Not really.
I've been collecting phase data on the REF-0 and Denuo GPS as the pair warms up. My equipment is quite limited, and it's difficult for me to collect useful frequency data in the E-13 range. So I thought I'd just measure the phase difference between the REF-0 PPS and a stock REF-1 with the Oncore GPS. Perhaps measuring the two relative to each other will provide some insight on how a REF-0 performs with a non-timing GPS.
No data was collected for the first two days. I did monitor it casually on the counter, and it was exactly as you'd expect. Lots of big swings and settling.
Below are traces showing T + 48 to 72 hours, and T + 72 to 96 hours.
|Notice the "pop" of noise during day three of the warmup.|
|Make sure to notice the scale when comparing this plot to the first one.|
It's difficult to know what's causing what in these plots. The REF-1 has a 15 year old GPS receiver. The REF-0 has a non-timing GPS with no position hold, but great sensitivity. Better references and lots more time will be required to know more.
Though, something interesting happens when you overlay the two plots.
|Plots from two consecutive 24 hour periods shown together.|
The consistency between them in many spots is easy to see, even though the traces are separated by exactly 24 hours from each other. Especially during the middle of the plot, which would have been the overnight hours, the two follow each other closely. I'm not sure if there's actually anything useful to glean from that.
That's all for now. There's not much data yet, but any comments are welcome. We'll see how the unit does after a week of being on, then a month, then....
Thanks for reading!
- Dan W.