Forums > Windsurfing   Gps and Speed talk

Where to put a mobile phone for GPS logging

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Created by Henners 1 month ago, 23 Nov 2020
Henners
21 posts
23 Nov 2020 4:29PM
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Hi everyone,
I have an old mobile phone and a waterproof bag for the phone. The waterproof bag has a lanyard on it but I am a little bit hesitant to put it over my neck and shove the phone down my wetsuit.
I was thinking I could tie the lanyard to the puller part of the zipper on my impact vest and then shove the bag inside the impact vest.
I know I am overthinking this but I don't really want to lose the phone and I don't want to strangle myself on a lanyard.
Is anyone else using a mobile phone to track their speed? Have you got a better idea of where to stow the phone?
Also, I thought I might try out "WindsportTracker --GPS Windsurfing & Kitesurfing" app on android it looks uncomplicated and as a good set of features. Anyone using it? Any other apps out there that might be better?

JulienLe
184 posts
23 Nov 2020 4:31PM
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Any wet layer will detune the antenna. But if you fear losing it, well try it like that and see where it gets you. It might be very acceptable.

decrepit
WA, 10262 posts
23 Nov 2020 5:43PM
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you can buy water roof armband phone holders, some even have earphone sockets, so you can hear your speed told to you as you sail.

Some people love this, but there's a one second or more delay, it's still telling you 10kts after you've come to a complete stop. I have trouble making use of this, this old brain needs instantaneous feedback to be able to use it.

AS Julien says having a layer of wet material over the antenna can completely kill the GPS signal. The best place for a GPS is the upper arm or head. Phones also vary in accuracy, none are approved for GPSTC posting, but it's possible to use an accurate blue tooth gps logger for the GPS signal and the phone for the display. I haven't used windsport tracker, I've used gpslogit and found it fine for my purposes, but the phone is a bit large and awkward, the earphones kept falling out, and there's smaller more convenient devices that are approved, so I haven't used a phone for several years.

Ben1973
518 posts
24 Nov 2020 3:00AM
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I've thought about wrapping a cord around the mast above the boom then have I dangle down inside the luff tube of big sleeve race sails.
than I just brought a small hydration backpack and put it in one of the pockets. Just so you know sea water seems to be able to get through 3 ziplock bags and kill your phone.

olskool
QLD, 2049 posts
24 Nov 2020 6:24AM
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If you wear a flotation vest secure it to the shoulder.

sailquik
VIC, 5320 posts
24 Nov 2020 8:38AM
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This is the best phone armband case I have found:

H2Oaudio. I think the company brand name has changed now to Amphibex. It has an earphone plug but I find with some cheap Android phones I can hear the speed talk well enough without using waterproof earphones.











h2oaudio.com/products/amphibx-waterproof-smartphone-case

decrepit
WA, 10262 posts
24 Nov 2020 10:13AM
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Thanks Andrew, that's the one I used, when I wore a phone. Have to agree it's the best I've seen.

Henners
21 posts
25 Nov 2020 12:20PM
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Thank you very much to everyone. Yeah, I think your right about shoving it down my impact vest, it is most likely not going to pick up the GPS signal.

segler
739 posts
26 Nov 2020 2:06AM
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I have had good luck with Aquapac bags. Various sizes.

rp6conrad
2 posts
29 Nov 2020 4:01PM
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I use a (cheap) watertight bag with my Samsung S7. This goes into my wetsuit on the chest. As the S7 is a waterproof phone, I am pretty confident that the phone will survive. Just the salt water is dangerous for all connectors, so better avoid it. I use the "Windrace" app, which works very well for me. This app records also in "Doppler" speed, so the results seems very reliable. You can upload direct to GPS-speedsurfing, althought there is a mistake in the calculation from the avg speed ! (takes 5 runs out of 1 long run). But if you use the gpx log file for uploading, everything is correct. I never had GPS receiving problems.

sailquik
VIC, 5320 posts
29 Nov 2020 8:38PM
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Select to expand quote
rp6conrad said..
I use a (cheap) watertight bag with my Samsung S7. This goes into my wetsuit on the chest. ..... I never had GPS receiving problems.


You will....

rp6conrad
2 posts
29 Nov 2020 8:30PM
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After 67 sessions over the last 3 years, i had never problems with this combination (S7 - Windrace). Maybe the reason for this is the construction of the S7 : It has no metal back cover, but a glass cover. So the GPS antenna is not influenced / masked with a metal back. As bsecond device, I use a Suunto Ambit 2. This has the advantage that you can directmy check your speed.

sailquik
VIC, 5320 posts
29 Nov 2020 11:57PM
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Select to expand quote
rp6conrad said..
After 67 sessions over the last 3 years, i had never problems with this combination (S7 - Windrace). Maybe the reason for this is the construction of the S7 : It has no metal back cover, but a glass cover. So the GPS antenna is not influenced / masked with a metal back. As bsecond device, I use a Suunto Ambit 2. This has the advantage that you can directmy check your speed.



You must be a super sailor who never gets his wetsuit wet.

Either that, or you have just never noticed that your GPS data is sometimes crap.
Wet, wetsuit material, and body parts are well known to very effectively block radio (GPS) signals and cause lower satellite count, missed data points, sudden switching between different satellites when you turn (which caused spikes and lost data) and far more error than otherwise.

There is no magic that can suck radio signals through wet materials and water filled body parts no matter how good the technology of the antenna. There are however, lots of tricks a smartphone maker can implement in his GPS chip to smooth and disguise gaps and errors.

But hey! If you are happy with what you get and are only posting to a 'Fun' ranking, thats is all that matters.

Sandman1221
397 posts
4 Dec 2020 7:34AM
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I use a Yeti fanny pack, has a magnetic closure, keep my anemometer, tools, shims, and phone in it, waterproof. Adds a little flotation too when in the water.



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Forums > Windsurfing   Gps and Speed talk


"Where to put a mobile phone for GPS logging" started by Henners