Forums > Windsurfing   Gps and Speed talk

Makai GPS unit

Reply
Created by dcenzed > 9 months ago, 7 Jun 2016
dcenzed
34 posts
7 Jun 2016 4:49PM
Thumbs Up

Has anyone tried the new makai gps unit? Are they finding that the gps distance is not accurate? I am finding that it is out about 400m over 5 kms

decrepit
WA, 11881 posts
7 Jun 2016 5:23PM
Thumbs Up

That's a huge discrepancy, how are you measuring the 5km? You're not trusting your car's speedo are you?

yoyo
WA, 1646 posts
7 Jun 2016 5:29PM
Thumbs Up

Reading through the forum posts on the Velocitek site there seems to be quite a few who are finding big discrepancies in the speed and dist log info. I'm unable to find any technical info , but they DO say the measurement is by Doppler speed shift. Having said that it does reminds me of the speed/dist calculated from positional points and velocity /dist from Doppler speed debate.

Anyone who has used the Windrace app (which produces BOTH positional and Doppler graphs) will realise the Positional info is rubbish compared to the Doppler info.

The Velocitek guys appeared to know their stuff years ago but produced really clunky looking devices. Everything is much slicker now as a consumer device. I wonder if the technical stuff has taken a back seat to marketing and the Makai uses positional data instead of Doppler.

Interestingly some forum writers said their units (non Makai) which were fine before being replaced under warrantee but the replacement had speed spikes all the time.

I wonder if they are using different masking or a different chip which gets more multipathing than previous gps chip.

The administrators gave numerous reasons/excuses for the spikes but ignored the fact the previous unit in the same mounting position gave no spikes.

Android phones with gpsLogit or Windrace are very accurate. I suggest you go for a ride/drive with both your Makai and a phone. Download the tracks . If there is a discrepancy then send the files to the Velocitek guys and ask them to explain the discrepancy.

yoyo
WA, 1646 posts
7 Jun 2016 7:39PM
Thumbs Up

Just an additional thought about the Makai. Through testing on windsurfers clear sky is very important and with a good view there are almost zero spikes and the only ones are where you fall in. It does not take much water to interrupt a gps fix. And when the gps tries to regain its fix it is often many 10s of metres out. On a sup I imagine in Maui/WA coastal conditions the Makai will be continually swamped by waves if mounted as per the velocitek site. This may be the problem.




dcenzed
34 posts
9 Jun 2016 5:25AM
Thumbs Up

Bit hard to drive the car on the water... I have had my Garmin Fenix 2 and the iphone at the same time, they are within a few metres of each other.

dcenzed
34 posts
9 Jun 2016 5:29AM
Thumbs Up

yoyo said..
Just an additional thought about the Makai. Through testing on windsurfers clear sky is very important and with a good view there are almost zero spikes and the only ones are where you fall in. It does not take much water to interrupt a gps fix. And when the gps tries to regain its fix it is often many 10s of metres out. On a sup I imagine in Maui/WA coastal conditions the Makai will be continually swamped by waves if mounted as per the velocitek site. This may be the problem.






Have contacted them to see if there was a reset button or firmware user replacement upgrade and they've said to send it back, problem is that this leaves me without real time gps speed for a few weeks.
In reference to your previous post, I had my iphone and the fenix 2 to test accuracy, the fenix also gives a stroke or cadence count as well, the makai was really different and the other 2 were in a few metres of each other.

yoyo
WA, 1646 posts
9 Jun 2016 5:59PM
Thumbs Up

Select to expand quote
Bit hard to drive the car on the water... I have had my Garmin Fenix 2 and the iphone at the same time, they are within a few metres of each other.



Not sure about iPhone but there are several windsurfer with Android phones who use the speaker function of gpsLogit and Windrace that calls out the speeds in knots or kilometre/hr. You can adjust the settings but the default usually just says the speed when it changes. I'd imagine the iPhone has similar apps. The rest of the time they listen to music.
The fact your Fenix and iPhone on your arm had the same reading suggest waves/water over the Makai gps antenna/unit is the problem and unless you also put it on your arm it is always going to be out.

If you compared the 3 gps on land and they come up with similar track results then you can conclude having the antenna at water level is not a good way to go. If you MUST have a visual display then you could use Bluetooth.



Subscribe
Reply

Forums > Windsurfing   Gps and Speed talk


"Makai GPS unit" started by dcenzed