A few months ago I noticed that with my Qstarz 818XT set to 5hz RC seemed to lag behind my actual position quite noticeably. If I recall correctly, it didn't seem to be updating but maybe one per second.
Setting the switch to 10 HZ worked much, much better, and you could tell my position was being updated more than once per second.
The 5HZ mode seemed to work better once I enabled the "Do not modify settings" GPS option.
It's my understanding (from previous advice with TrackMaster) that I should try to run the 818XT in 5hz mode because it'll provide better accuracy using differential GPS.
Does anyone know, for sure, the ideal way to set up your 818XT with RaceChrono to get the most accurate timing?
Thanks,
Bob
Comments
I've heard from one other user that the "Do not modify" setting is needed to fix the problem. This may be related to the flow control bug in Android we experienced with Garmin GLO.
I will retest this and report back on it's current state.
What's the default for the "Do not modify settings" option? What does this setting affect?
I tried the following settings:
"Do Not Modify" = Checked + 5 Hz Mode = 1 second lag
"Do Not Modify" = Checked + 10 Hz Mode = 1 second lag, maybe a tick less
"Do Not Modify" = Unchecked + 5 Hz Mode = big lag
"Do Not Modify" = Unchecked + 10 Hz Mode = big lag
I checked the lag by driving around in the map view, and comparing the time I really passed a spot to where it showed me passing it on the map.
Since I have no idea how quickly the phone is able to redraw screen positions, I don't know how accurate it really is. It might be, however, precise... in it's lag... which might be just fine for lap times.
And since the 5hz mode on the 818XT is *supposed* to be more accurate due to WAAS, I'm gonna go with 5hz and "do not modify".
In doing all this I realized that I have no idea how much more or less accurate Trackmaster is than RaceChrono, because it doesn't even have this mode where you can see how close it is.
p.s. For those that don't know, you have to turn on the 5hz mode and differential GPS using the QStarz program.
Short presentation:
- I used years ago RaceChrono with Nokia E65 and Qstarz 818X - 5Hz
- I start again with Android release on Samsung Galaxy S3 (v:4.3) - Qstarz 818X - 5Hz
- Usage = Karting in France
I used RaceChrono last Saturday and it seems that GPS data are missing.
Sessions presents parts of the track and some direct line appears when missing GPS data.
I created a new track name with only a "Start/Stop" point (using google view)
Qstarz was set to 5Hz (physical jumper)
Qstarz was paired with Samsung S3
RaceChrono / Parameters / Devices / Device1 = Used - GPS Bluetooth - Qstarz GPS - MTK-II
Windows Qstarz GPS View app presents 5Hz and I set DGPS / SBAS
Newbie question => Where is the "Do not modify settings" GPS option ?
Do you have any idea to help me ?
Do you need more details ?
Do i miss something into Qstarz configuration ?
Regards
saturne06
I have a Samsung Galaxy S3 with Android v:4.3 and Qstarz 818X - 5Hz
Do you think this package will works ?
My first test show me sessions with good parts of the track and some direct line appears when "perhaps" missing GPS data.
=> Do you have a checklist of controls I have to do during next test ?
Regards
Saturne06
1) Do you use RaceChrono to connect directly to the Bluetooth GPS? Do not use any external app to connect it.
2) Also update to latest RaceChrono version (v3.20).
3) Make sure you un-pair any hands-free device, to disable them from connecting to your phone
4) Make sure the GPS is in good location, in direct view to the satellites in the sky. Lower part of the windshield on the dash, or rear section of a motorcycle.
Happy this package works for you ;-)
Qstarz is directly connected to Galaxy S3
Latest release 3.20 was still installed last Saturday
The only device available into Android / Bluetooth is Qstarz GPS
I unpaired it
Turn on the Qstarz
Paired it again with 0000 key
Into RACE CHRONO, I uncheck device #1 and check it again
I run RACE CHRONO /START / and I saw satellites / Lower part of the windshield on the dash
On Screen:
Receptor GPS ---- 5Hz
Bluetooth (Qstarz GPS)
Connected - 14.5 kbit/s, 5 satellites
I don't move so less usable information:
- Altitude => Ok (185m)
- DOP Horizontal => 1.93
- DOP Vertical => 0.98
- Satellites => 5
- Fix type => 1
All seems to be ok; I will test again next Saturday with several locations for Galaxy S3 and Qstarz
(Currently, Samsung is fixed on the Wheel and GPS Qstarz on the fuel tank (less than 50 centimeters)
Bluetooth issue hypothesis: When I take a look into sessions, some direct line can represent 15mn driving ...
FYI: I have no Internet access / 3G on the track with Samsung Galaxy S3
I will get back to you next week with more details or a good news (I'll prefer)
Saturne06
5) Reboot your phone prior to the session
6) Fully charge the battery on the GPS receiver, and remove the battery for 5 seconds to "reboot" it
No internet connection should not matter. Also the problem could be about losing lock to satellites. But if the trajectories look "ok" elsewhere and then cut through the track randomly for long period of time, it does sound like a bluetooth problem to me.
I found my issue last Saturday.
Before using again my Qstarz, I replaced battery with a Nokia BL5C (the original was out) and this battery is slightly thinner and Kart vibrations made the battery disconnect some time.
It was the 15 seconds off I saw into sessions with a direct line which make me thought a battery issue.
I put small foam into Qstarz and a scratch to make it blocked
Sessions are now good !
YES !
Before driving, I reboot the phone and remove Qstarz battery 5 seconds.
Sessions are good and the line is on the track
Thanks AOL for your help.
Next step will be to analyze sessions and all features of RaceChrono.
=> You really made a good lap timing software
Saturne06