276C Losing Time

[marco polo]

I just pulled out my 276C and flashed it up a few days ago and noticed the date was off by a couple of weeks, and the time was way off as well (it thought it was nighttime in broad adylight). I charged it up and nothing changed. Given it's winter up here, I haven't used in since November. Are the date/time screwed up simply because it has not accessed satellites in 3 months? I tried acquiring satellites at the window, but that didn't work and it's too damned cold to stand with it outside.

[9Dave]

Originally Posted by marco polo

I just pulled out my 276C and flashed it up a few days ago and noticed the date was off by a couple of weeks, and the time was way off as well (it thought it was nighttime in broad adylight). I charged it up and nothing changed. Given it's winter up here, I haven't used in since November. Are the date/time screwed up simply because it has not accessed satellites in 3 months? I tried acquiring satellites at the window, but that didn't work and it's too damned cold to stand with it outside.

Go stand outside and acquire a sat. Everything will be just fine!

Dave

[bmwbill]

I had the same thing happen to me, except, instead of losing weeks, I lost years (actually gained years...2010!). Like you, nothing I did would clear it up, until I talked to Garmin. I don't remember whether I reset the date, and than acquires the satellites, or the other way around. Put on all your warm clothes and acquire some satellites and all should be fine...it worked for me.

Bill

[marco polo]

Originally Posted by bmwbill

I had the same thing happen to me, except, instead of losing weeks, I lost years (actually gained years...2010!). Like you, nothing I did would clear it up, until I talked to Garmin. I don't remember whether I reset the date, and than acquires the satellites, or the other way around. Put on all your warm clothes and acquire some satellites and all should be fine...it worked for me.

Bill

That's easy for you to say in California. Thanks guys for the tips. As I expected. I'll stand outside brrrrr.

[Blrfl]

Originally Posted by marco polo

Are the date/time screwed up simply because it has not accessed satellites in 3 months?

Probably. The clocks in most GPS receivers are inexpensive and don't work very well for stand-alone timekeeping. With discipline from the satellites, they keep time just about as well as a $65,000 atomic clock, but once that goes away they drift like mad.

With one satellite you can get time that's accurate but is behind by the amount of time it takes for the signal to get from the satellite to the receiver. Get three more and your clock will be locked onto UTC.

--Mark

[AugustFalcon]

[quote=Blrfl]...Get three more and your clock will be locked onto UTC.../quote]

Nah... GPS time was 14 seconds ahead of UTC as of 1/1/6. No leap seconds in GPS time.

[GuinnesS]

The earthquake that was responsible for the Big Tsunami was said to be so violent that the axis around which the earth spins was induced with a 2cm wobble. As a result (it is said) the Earth now spins at a very slightly greater speed, making each day shorter by 1/2,000,000 th of a second. You might want to check the 'Sell by' date on that there Garmin unit

[Blrfl]

Originally Posted by AugustFalcon

Nah... GPS time was 14 seconds ahead of UTC as of 1/1/6. No leap seconds in GPS time.

True dat, although technically GPS does carry correct UTC because the nav message contains a frame with information on how to convert one to the other.

It's all so much bluster anyway, becaue even though GPS time has been steered to within 10ns of UTC since 1994, the spec only guarantees 100. And that could make me severely late for my morning meeting.

--Mark