[time-nuts] Thunderbolt & Lady Heather 48 hour precision survey

[Bob Camp]

Hi

Of course you *do* have the excuse that you had to stop and think for a second as to weather it *was* east or west of Greenwich ...

Bob


On Nov 27, 2010, at 5:33 AM, Rob Kimberley wrote:

> Comes down to the simple fact that it needs to know its position accurately
> in order to give you good timing. I found this one out the hard way many
> (many) years ago with an old single channel Trimble unit, where we had to
> manually enter a known position in order to speed up acquisition. We were in
> London at BBC Broadcasting House, and I inadvertently put the longitude of
> the site East instead of West of Greenwich, and wondered why my 1PPS was
> ramping off!
> 
> :-)
> 
> Cheers
> 
> Rob Kimberley
> 
> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> Behalf Of Robert Darlington
> Sent: 26 November 2010 6:41 AM
> To: Discussion of precise time and frequency measurement
> Subject: [time-nuts] Thunderbolt & Lady Heather 48 hour precision survey
> 
> For the last year I've been wondering why my thunderbolt doesn't perform as
> well as I thought it should.  Now I know why (at least I think I know why).
> I keep it in a styrofoam beer cooler surrounded with bottled water in a
> draft free area and it's been all over the map.   I tried doing a 48 hour
> survey through Lady Heather and it ended a few hours ago and there is now a
> huge improvement in PPS stability -no more +/- 40ns excursions.  I'll be
> keeping an eye on it for a bit but I think the survey helped significantly.
> I'm almost sure I did a survey when I first got it but maybe I somehow
> skipped over that.  Anyway, hope this helps somebody.
> 
> -Bob
> 
> 
> 
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