The Beta 5 version of the SpeedReader site is now online at www.ka72.com/

I have updated the 5x10 calc to be one-per-run and the calcs are now in line with Realspeed in 12 out of 14 of my sample files the other two files are within .02kts, and in both cases the variation is sure to invalid records that Realspeed filters out. (ka72 does no filtering at present.)

Also I updated the firmware revision checking for GT-31s.

You should now find that the results you get from the site are in line with the results obtained from Realspeed. I'd like to take a moment to thank Mal Wright for his invaluable input on this project.

Dylan.

Hi Dylan,

I don't think that the one per run system is working, the last file I sent would be a good test case for this. I had one big long run downwind at around 23 knots, the rest of the day was more like 20 knots.

Here are the results, the numbers I posted to the GTC are in bold:

2 Second Peak (kts): 23.52 23.521
5x10 Average (kts): 22.7 19.536
1 Hr (kts): 10.75 10.752
Alpha 500: 14.27 13.744 (This was using trackpoints, using doppler was 13.513)
Nautical Mile (kts): 17.98 17.979
Total Dist (dop): 22.82 22.816

The reader is coming along nicely, I'm impressed with it!

Dylan,
I'm new to this caper, have a GT31 using Realspeed, but I don't have any .SBN files...
so I get a reject message.

Where do I find, or how do I generate .sbn file(s) ??
cheers

Hi Peter,

its a setting on your GPS.


Make sure your GPS is set according to the guide here:

http://gpsteamchallenge.com.au/guides/setupgt11_2008.php

Off the Mt Best page these memory card settings are probably what you need:
mtbest.net/setting-up-navi-GT-11.htm

Setting up GT11 manually
1. MEMORY CARD
a. LOG SWITCH should be ON-FIX. There is no point to log any data when there is no position fix.
b. NMEA ITEMS should be set to "SBN 1 SEC" in recent firmware. Binary logging ensures maximum possible trackpoint accuracy and maximum data reliability. If you want the most complete data set from your sailing session, use SBN (binary) format logging.
c. MIN SPEED should be set somewhere between 2 and 5, unless you are specifically interested to log data when you are stationary.
d. FORMAT CARD. Read readme.txt file to find which cards are compatible with GT11. Format the card a few times in a row. If you succeed each time, you can rely on the SD card that you use. Formating is the most drastic writing operation you can perform on your card and hence it is the ultimate test of your SD card compatibility.
e. FILE SIZE should be set to CARD SIZE. This means that you do not put any limit on file size.

Got it!

Thanks Karl

All set...now bring on the N/Easters

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shear tip said...

Karl's right, that's the site for Navis. But you might just want to double check your settings on the GT-31 page, I'm not sure how different it is from the GT-11 setup:

http://mtbest.net/setting-up-navi-GT31.htm

Oops! Sorry about that. I've compared Laff77's GT-31 to my GT-11 with the latest firmware. They seem quite similar to each other but there are sure to be differences.

Tried out Dylan's online speed reader and compared it to the results from Realspeed for yesterday's sail. Guess you could do a HTML table here but too lazy so I'll just list the results:

Division Realspeed------ KA72.com Online speed reader
2 Seconds 24.81----------24.51
5x 10 secs 22.68---------22.09
1 hour 7.74---------------7.92
Alpha 500 15.42---------15.24
Naut mile 15.48---------15.29
Distance 18.33----------18.89

Hi Moby,

You've probably got your version of Realspeed set up to use trackpoints instead of doppler.

For every division (except Alpha), right click on the division, select "Edit...", then click on "Use Doppler if available". This should give you numbers that are very close to the KA72 reader.

Select to expand quote

nebbian said...

Hi Moby,

You've probably got your version of Realspeed set up to use trackpoints instead of doppler.

For every division (except Alpha), right click on the division, select "Edit...", then click on "Use Doppler if available". This should give you numbers that are very close to the KA72 reader.

True, they were set to trackpoints. Thanks man. Hope your bus is going well.

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nebbian said...
I don't think that the one per run system is working, the last file I sent would be a good test case for this. I had one big long run downwind at around 23 knots, the rest of the day was more like 20 knots.

I am looking at that file now, and I admit I am a bit baffled as to how Realspeed tells when one run has ended and the next starts.

For instance, the transition between run 2 and run 3 in your file (which occurs at about point 950 in the file (without removing invalids)) looks totally weird. You are sailing the same course, with the same general bearing and speed, and yet Realspeed jumps onto a new run.

There is obviously something else at work here.

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Dylan72 said...

nebbian said...
I don't think that the one per run system is working, the last file I sent would be a good test case for this. I had one big long run downwind at around 23 knots, the rest of the day was more like 20 knots.

I am looking at that file now, and I admit I am a bit baffled as to how Realspeed tells when one run has ended and the next starts.

For instance, the transition between run 2 and run 3 in your file (which occurs at about point 950 in the file (without removing invalids)) looks totally weird. You are sailing the same course, with the same general bearing and speed, and yet Realspeed jumps onto a new run.

There is obviously something else at work here.

Hmmmm... around point 950 I'm on run 16 on my version of realspeed! The transition between run 2 and 3 is where I'm walking around in the carpark before the session.

Not sure what yours is doing.