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Created by bedzplane > 9 months ago, 23 Feb 2018
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Probably a different alpha then, That's why it's good to process your own data, (especially with alphas,) you can see what's going on.

The 20 on the watch may have just been within the 50m using doppler but just outside using trackpoints. That would let you know that you're going too wide. if it's a valid alpha using both methods, there should only be fractions of a knt difference.

www.ka72.com/Track/t/360529

Here is the track from 3/11/18. The watch said just over 20 knot alpha and after uploaded to KA it was knocked back...sorry it was reduced to 19.634. Not sure if it was the same alpha but I'm pretty sure it was the same turn.

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www.ka72.com/Track/t/360529

Here is the track from 3/11/18. The watch said just over 20 knot alpha and after uploaded to KA it was knocked back...sorry it was reduced to 19.634. Not sure if it was the same alpha but I'm pretty sure it was the same turn.

all I get is cesium, how do I download the file?

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www.ka72.com/Track/t/360529

Here is the track from 3/11/18. The watch said just over 20 knot alpha and after uploaded to KA it was knocked back...sorry it was reduced to 19.634. Not sure if it was the same alpha but I'm pretty sure it was the same turn.

all I get is cesium, how do I download the file?

You download tracks from the "search " menu.

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www.ka72.com/Track/t/360529

Here is the track from 3/11/18. The watch said just over 20 knot alpha and after uploaded to KA it was knocked back...sorry it was reduced to 19.634. Not sure if it was the same alpha but I'm pretty sure it was the same turn.

all I get is cesium, how do I download the file?

Sent you the link Mike.

Got it, and you're right it's the same gybe, but you went wide, so it's very short, only just got it into the watch's 300m.

so here's what it looks like with Real speed.

You can see the total distance is only 313.2m. because that's where trackpoints puts your 50m separation.

If you add another 3m and calculate for 53m

here's what you get.

So another 3m separation gives you an extra 43m total distance, lifting the average speed.

So I conclude from this that the watches doppler calculation of separation is an extra 3m here. So safest if you want to make sure of your alphas, aim for 47-48m not 50m

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OK,

Got it, and you're right it's the same gybe, but you went wide, so it's very short, only just got it into the watch's 300m.

so here's what it looks like with Real speed.

You can see the total distance is only 313.2m. because that's where trackpoints puts your 50m separation.

If you add another 3m and calculate for 53m

here's what you get.

So another 3m separation gives you an extra 43m total distance, lifting the average speed.

So I conclude from this that the watches doppler calculation of separation is an extra 3m here. So safest if you want to make sure of your alphas, aim for 47-48m not 50m

Hey thanks for checking it out.

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Hey thanks for checking it out.

It's really not a problem, having your own software can tell you a lot about what is happening, this case demonstrates that rather well.

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Hey thanks for checking it out.

It's really not a problem, having your own software can tell you a lot about what is happening, this case demonstrates that rather well.

Software analysis is very interesting. Again thankyou for your time and energy.

This case also demonstrates that the watch gave a higher alpha on the day than what KA gave and subsequently posted on gpstc.......hence my initial point that I made to Sue, that I noticed a difference on an alpha when she asked if any scores were 'knocked back' by KA.