Re: OT 10Mhz references

Torch Fireman


Yeah, I read that story when I googled "time-nuts". Cool stuff. It got me to wondering: If (as he demonstrated) time dilates with distance from the gravity well of the earth, doesn't that make GPS based reference standards inherently less accurate than earth based ones *on earth*? I'm sure the smart folks worked out some sort of compensation for long-term effects. Perhaps the GPS birds are receiving corrections from a ground station (in which case, calibrating a ground-based oscillator to the bird would make it run faster than it should). Or perhaps the GPS oscillators are running at a slightly slower rate than earth-based ones, technically making them inaccurate at their actual orbit.

Personally, back in the real world of doctor's appointments and bus schedules, my house standard is a wrist-watch that sets itself from the radio signal from Boulder every night. But it was out by an hour this morning, since it was made before the powers that be changed the DST dates, making the automatic DST setting useless. So I had to manually correct the hour. When I set the clocks in my cars and house to DST this morning, I used the watch as a reference and now all my clocks are within 0.5 minutes of that signal, which should get me to work on time tomorrow morning. ;-)

On 12/03/2016 10:51 PM, 'Dennis Tillman' [TekScopes] wrote:

he took his kids camping for
a weekend to Paradise which is 7,000 feet up on Mt. Rainier near us in
Seattle. Of course Tom does things a little differently than the rest of us.
He brought 3 HP Cesium Standards up with him on the trip. When he got back
down he compared the time dilation that occurred between the three Cesium
Standards up on the mountain for the weekend with the ones he kept in his
house which is almost at sea level. He then calculated the expected time
difference based on General Relativity.

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