[time-nuts] Venus838LPx-T preliminary testing

[Nick Sayer]

I got the first breakout boards back today. There’s an error on them I had to workaround, but having done that I was able to observe it getting first-fix (with good reception, TTFF is remarkably good, FWIW), then performing the 2000 point survey and generating quantization error messages.

I’ve collected an hour’s worth of quantization error data (as reported by the unit) and attached it here, for those who wish to analyze it. It’s very, very jittery, but confined to a ±6 ns corridor. I was able to see what appeared to possibly be very, very brief hanging-bridge-like anomalies, but overall it looks just really noisy to me.

After the survey, the GGA position reported has not changed, which is as I’d expect. I don’t know if the unit periodically validates the position solution to insure it hasn’t been moved.

I don’t have matching PPS jitter data to go along with this. It’ll be interesting to attempt to correlate the two to get a picture of post-correction PPS stability, if I can.

I’m going to make a breakout board for these and list them on Tindie next week, for those who wish to play with them.

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