Hi guys,
I normally use Gpsresults on its own but through a friend have just discovered the convenience of KA72 in working it all out and providing a google earth overlay...

My question is about alphas, When I upload a file to KA72 it seems to not take into account the 50m radious rule for alphas...

I have the alpha width on gpsresults set at 50m which when measuring tracks against google earth seems to work as it should. However when uploaded to ka72 I get lots of new alphas but they dont appear on gpsresults unless I turn the filter off.

EDIT: I have found on a site that KA72 only requires an alpha to be 100m long, On GPSTC it states an alpha is 500m long.. upon uploading form ka72 to gpstc does it only include alphas over 500m in length or should I be making that calculation manually through gpsresults?

any thoughts?

The alpha length definition is "No more than 500m" same as the separation, "no more than 50m".

I haven't used gps results, but I've had very similar results with realspeed, GPSARPro and KA72.

It may be that gpsresults doesn't allow the alpha to drift over 50m anywhere along it's length whereas the others are only looking at the start/finish point.

So Ka72 will only upload alphas 500m or under. And most of them are a bit under, (at 25knots each one second data point is about 13m apart, at 30knots they're over 15m apart)

If you measure the start finish deviation on the extra alphas from ka72, what widths do you get??? I'd be very surprised if they're over 50m.
Can you set the gpsresults filter to 51m to 55m, there may be a slight difference in measurement.
Is gpsresults calculating using doppler or trackpoint data?? I use doppler and so will ka72 if it's available, if your using trackpoints that may give a slight difference in measurements.

Ok, thanks Decrepit.
So far I have only been posting alphas of around 500M so thats good to know. KA72 seems to make the whole process easier so I will use that more I think as gpsresults doesnt seem interested in any alpha under about 450m

Is it fair to say a 500m alpha will most likely have a faster avg than a 250m?

Usually, because there's more of the fast straight leg in the average.