Forums > Windsurfing   Gps and Speed talk

GPS said 28Kts, KA72 said 22?

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Created by adamhatfield > 9 months ago, 24 Feb 2014
adamhatfield
NSW, 171 posts
24 Feb 2014 10:23AM
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I went out yesterday and had a nice sail for an hour or so. When I came in I noticed my GPS said 28kts which I was stoked about as it would have been a new PB for me.

I then loaded my file onto KA72.com and came up with a 2 sec result of 22.15. I was understandably disappointed as I was sure I was going a lot faster. Session results here: www.gpsteamchallenge.com.au/sailor_session/show?date=2014-02-23&team=9

I then switched on the GPS and sure enough I saw a max speed of 28.49Kts:
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Any ideas what happened? I know I never leave it switched on for the drive home. None of my tracks have ever had speeds near 28Kts when I upload to KA72. But it seems to me that my GPS thinks it has gone over 28 kts.

adamhatfield
NSW, 171 posts
24 Feb 2014 11:30AM
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That seems to have been a different session to yesterdays: Here's yesterdays track: http://www.ka72.com/viewge.aspx?fid=58081&tid=7

Also here's a link to all the datalogger information: www.dropbox.com/s/mhi3pwlrosh8s9n/ADAM%20HATFIELD_933000190_20140223_123839_DLG.SBP

None of those seem to have any results close to 28kts. Here's what Ka72 reports: anon.ka72.com/TrackRecalc.aspx?fid=58081

lao shi
WA, 1338 posts
24 Feb 2014 9:08AM
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Had a look and it is a spike (skipped a second). However the track in realspeed does show what appears to be a valid result of 24.89 but with only 6 satellites which may be why KA72 is not showing it. You want 8+ ideally
Have a look at where you are wearing the gps and make sure that it does not go under your arm or get blocked by something you are wearing.

adamhatfield
NSW, 171 posts
24 Feb 2014 12:33PM
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Bugger, I've had this vague hope that my GPS is faulty and I am actually quicker than it is showing. No such luck.

I wear it on my arm so I would have thought it would have good coverage. I'll make sure i wear it somewhere it can't be missed.

Thanks for taking a look.

Kazza
TAS, 2344 posts
24 Feb 2014 1:13PM
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It probably means you didn't hold the 28.49 for 2 sec's, that was your max speed but not for long enough.



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Forums > Windsurfing   Gps and Speed talk


"GPS said 28Kts, KA72 said 22?" started by adamhatfield