Forums > Windsurfing   Gps and Speed talk

GW52 max speed change?

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Created by decrepit > 9 months ago, 4 Feb 2016
decrepit
WA, 11882 posts
4 Feb 2016 6:12PM
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I'm inclined to ask locosys if they can give us the 2s average as well as the 10s average, even if it means loosing the max speed output.

On 5hz the max speed is often a whole knot more than the 2s average, my feeling is a 0.2second peak is fairly irrelevant, and most people would prefer to see 2s and 10s.
Am I right in this, would anybody object to not having a max speed reading?

Saying this I've no idea if they'll do it, so if you want it don't get your hopes up.

Tony Polony
NSW, 337 posts
4 Feb 2016 9:38PM
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Agree Mike.

Despite the buzz you get when you see a great looking number, there's always the seed of doubt in the back of your mind knowing that it's going to be rounded down. If the device simply provided the user with the accepted reading that would only have minor variation from the uploaded result (in our case, 2 sec), I think it would be a good move forward.

My best speed has been a 37.1 peak on this device however once uploaded, the 2 sec was 36.2 Whilst I was simply stoked to finally get 33+, it was a bitter pill to swallow when I saw almost a whole knot be taken off my recorded peak.

Green light from me mate.

Windxtasy
WA, 4013 posts
4 Feb 2016 7:46PM
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Good idea Mike.
As the peak speed doesn't count for anything it is irrelevant, and misleading. The 2 sec would be much more useful.

sailquik
VIC, 6074 posts
4 Feb 2016 11:08PM
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If you want to see your 2 second speed, set the Genie at 2 seconds! You will always see the 1 second or 2 second average in the software anyhow.

The two second speed is NOT a 'rounded down' speed. It is the average speed over 2 seconds, which is obviously always going to be less than the peak speed over 1 second in the GT-31 or 0.2 seconds in the GW-52. Whats the big deal? It's always been that way.

I guess it would be possible for Locosys to release a firmware version that would allow you to set either Max speed or some average speed, but they may not be able to either.

If you carry two GPS as I recommend, so you have redundancy if something goes wrong, you can always set one to 2 second and one to 10 seconds, or any other time period you choose to gloat on. When at lake George last year I had one set to 60 seconds to get some indication of my NM (60sec was actually shorter, but it was an OK indicator.)

For me it is all redundant now anyhow, as I always use a Pixie3 ($19 currently) with GPS-Logit and see roughly results from every category instantly at anytime during the session.

decrepit
WA, 11882 posts
4 Feb 2016 8:17PM
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So Andrew, that doesn't sound like a "no" more like an "unnecessary"?

Te Hau
479 posts
9 Feb 2016 7:43AM
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Or, if you want to see a more realistic top speed, set the GW52 on 1Hz recording instead of 5Hz
Now you're seeing the 1 sec peak on screen as with the GT31.
Also, seems to be no spikes at 1Hz with plenty at 5Hz (even in my helmet).

sailquik
VIC, 6074 posts
9 Feb 2016 5:51PM
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Select to expand quote
Te Hau said..
Or, if you want to see a more realistic top speed, set the GW52 on 1Hz recording instead of 5Hz
Now you're seeing the 1 sec peak on screen as with the GT31.
Also, seems to be no spikes at 1Hz with plenty at 5Hz (even in my helmet).


Please don't set the GW-52 to 1hz. It is designed to be used at 5hz. There are no anti aliasing filters in it like the GT-31 so it need to used at 5hz to reduce possible aliasing errors.

Set the genie to one or two seconds instead of 10 seconds of you really need to see that on the water.

If you have GW-52 tracks with 'spikes' I wold really like to see them. That is something I have not really seen yet.

Mehore
NSW, 87 posts
9 Feb 2016 6:43PM
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Like most I'm striving for 40 knts one day. Just the other day I had a 2sec of 38.99 on the gt-31. Came down to 38.83 on Ka 72 ( PB woo)with close to a 38.2 10 sec. Would love to know if I hit 40 just for a sec or half a sec. For me thats what dreams are made of and maybe I can hang on for just a little longer next time. Im set to 2 sec and 10 sec

decrepit
WA, 11882 posts
9 Feb 2016 6:23PM
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Mehore said..
>>> Im set to 2 sec and 10 sec


How on earth are you doing that, the only way I know is to run 2 GPSs like Andrew suggested?
And if you really have a GT31 set to 2s I'm a bit surprised KA72 reduced it by that much.

decrepit
WA, 11882 posts
9 Feb 2016 6:26PM
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I've written to Kate, explaining that most of us would like to see 2s and 10s average, but I got an auto reply saying they're all on Chinese new year holiday, she won't be back until the 14th.
It will be interesting to see what her reply is.

decrepit
WA, 11882 posts
9 Feb 2016 6:30PM
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sailquik said..
>>>

Please don't set the GW-52 to 1hz. It is designed to be used at 5hz. There are no anti aliasing filters in it like the GT-31 so it need to used at 5hz to reduce possible aliasing errors.

>>>.


Andrew are you sure that the GW52 isn't averaging 5 of the 5hz results to log the 1hz result?
If that's the case it's still using 5hz but only logging at 1hz, I think that would give the same aliasing effects as logging at 5hz.

Mehore
NSW, 87 posts
10 Feb 2016 7:58PM
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I dont understand Decrepit! I allways expect to be dropped by Ka72 with my GT31 2 sec reading(.16 haa). 5x10 dont change at all. Are you directing that at me? Im happy still with Ka72 results. PB!! Yeh I gave you a red thumb .
Ok here we go! Maybe I should start using a different program to upload to the GPSTC! There's a few out there! Take your pick to get your best results. Yeh. Like it or not thats how it is. Why else would you want to use a program different to majority in challenge.
Me. I just want to stay on the same field as my fellow sailors, Ka 72! GO MARAUDERS!

decrepit
WA, 11882 posts
10 Feb 2016 7:10PM
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Mehore, It's just that I've no idea how you're setting the GT31 to 10s and 2s. I can only set mine to one or the other not both.
So are you also getting Max speed, in other words 3 speed results, or have you somehow hacked the unit and turned max speed to the 2s average.
That's exactly what I've asked Kate to do with the GW52

sailquik
VIC, 6074 posts
11 Feb 2016 2:41PM
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yes. Mehore. I think you misunderstand the GT-31.

The Speed Genie display give two types of readings.

The first is MAX SPEED which is a 1 second peak speed. (this can not be changed)

The other is NS Average which is set by the users and is usually set by us at 10 second average.

It sounds like you need a GW-52 so you can see if you peaked at 40 knots, even for 0.2 of a second!

sailquik
VIC, 6074 posts
11 Feb 2016 2:44PM
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decrepit said..
I've written to Kate, explaining that most of us would like to see 2s and 10s average, but I got an auto reply saying they're all on Chinese new year holiday, she won't be back until the 14th.
It will be interesting to see what her reply is.


Please request it only as an option to max speed that can be set by the user.

sailquik
VIC, 6074 posts
11 Feb 2016 2:55PM
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Te Hau said..
Or, if you want to see a more realistic top speed, set the GW52 on 1Hz recording instead of 5Hz
..........


The top speed shown at 5hz is "realistic". It is the actual peak speed the device actually calculated and recorded for 0.2 seconds. I am not saying is is 100% accurate, but it is realistic. The speed figures get more accurate as you take a longer speed sample. The 2 second sample is still no where near as accurate as the 10 second sample and has been also criticised in the past by some for being 'unrealistic'.

sailquik
VIC, 6074 posts
11 Feb 2016 3:02PM
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Select to expand quote
decrepit said..
sailquik said..
>>>

Please don't set the GW-52 to 1hz. It is designed to be used at 5hz. There are no anti aliasing filters in it like the GT-31 so it need to used at 5hz to reduce possible aliasing errors.

>>>.


Andrew are you sure that the GW52 isn't averaging 5 of the 5hz results to log the 1hz result?
If that's the case it's still using 5hz but only logging at 1hz, I think that would give the same aliasing effects as logging at 5hz.


Yes. Pretty sure. Manfred is as well.

Tom, Manfred and (I think) Chris did tests with the GT-31 and concluded it had a low pass filter. There is also some evidence that it actually may 'average' more data points to a 1 second logged value.

Mehore
NSW, 87 posts
13 Feb 2016 9:12AM
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sailquik said..
yes. Mehore. I think you misunderstand the GT-31.

The Speed Genie display give two types of readings.

The first is MAX SPEED which is a 1 second peak speed. (this can not be changed)

The other is NS Average which is set by the users and is usually set by us at 10 second average.

It sounds like you need a GW-52 so you can see if you peaked at 40 knots, even for 0.2 of a second!


Sorry guys for my ignorance I always thought it showed 2sec and 10 sec thanks fir that Andrew and Mike. I understand now



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