[time-nuts] Achievable temperature stability for Thunderbolt environment?
holrum at hotmail.com
Sat Jan 15 20:53:33 UTC 2011
Using Lady Heather's temperature controller (fan+cardboard box+solid state relay+baffling and thermal mass to taste) I get around +/- 3 millidegree temperature control when the AC/furnace is not running and +/- 20 millidegrees with them cycling. Long term temperature average is down in the tens of microdegrees. Under ideal conditions, I have seen over an hour where the temperature sensor did not move a single microdegree! The active temperature control has a most definite positive effect on the device performance.
I place the power supply in the thermal enclosure to minimize its output temperature coefficient. Yes, the thermal sensor is away from the oscillator module (and power supply) but in the semi-closed environment of the box, the thermal stability on one area is pretty much the same everywhere. I have chosen my box so that if the fan stops (for whatever reason) the temperature in the box still does not exceed 50C.
For the ultra best uber performance you need to maximize the quality of all the input and environmental variables (temperature, power, antenna, surveyed location, disciplining parameters, etc) Choose your antenna mask angle and signal level threshold to minimize satellite constellation switching. With a little nutty attention to the details you can get parts per trillion performance out of the little beastie.
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