Startseite › Forums › English › General Discussions regarding BT747

track download speed

Bild von ps-n
Mi, 10/20/2010 - 20:49 – ps-n

hi there. I use bt747 2.X.1652 with two gps loggers - iBlue 747 and iBlue 747 A+. Everything works fine, but I got one question about iBlue 747 - why download speed from this logger is so low?  iBlue 747 A+ works super fast.

Any suggestion for this? can I make downloading faster in bt747?(because in Gps Phototagger iBlue747 work's faster)

‹ m241 corrupted logs question Holux M-245 download log very slow ›
Mi, 10/20/2010 - 21:22 – mdeweerd
Bild von mdeweerd

The MTKII chipset has (as far

The MTKII chipset has (as far as I see it) the USB port on the chip itself, while with the MTK chipset, this is a normal serial protocol where an external USB/Serial chip was required.  Hence the older model functions at a real 115000 baud rate while the new model functions at the USB speed.

On the computer, the serial port is 'virtual' and just a software bridge with the serial protocol on the USB channel.

The reason for the speed difference that you observe between BT747 and the Gps Phototagger may be because of your device configuration.  When the device is in 'Overwrite' mode upon erase, BT747 will download the entire memory of the logger.  That is because that even when the log writing has wrapped (i.e., the memory was full and the logger starts overwriting the start of the memory), the logger will report that only part of the memory is filled.  If we believe that setting then we could miss downloading the previously written data.

You can set the download mode to 'Normal' and then the downloading will be only up to the reported filled position and it will not be 'smart'.

In the smart mode (the default mode), BT747 has some logic to avoid downloading previously fetched data again.  So when your memory is nearly full and you've previously downloaded the data, the download will surely be faster than with Gps Phototagger.

So my guess is that your device is in overwrite mode.  You can put it in STOP mode and erase the memory after which the download speed should be similar.

Do, 10/21/2010 - 09:37 – ps-n
Bild von ps-n

thanks for fast reply. I

thanks for fast reply. I checked the settings just now and it shows STOP when full. So I dont know what to do. 747A+ loads 10-20 seconds but 747 it takes 10 minutes or so.

Do, 10/21/2010 - 20:46 – mdeweerd
Bild von mdeweerd

How fulll is the iBlue 747?s

How fulll is the iBlue 747?s

Fr, 10/22/2010 - 22:24 – mdeweerd
Bild von mdeweerd

I erased your 20% answer

I erased your 20% answer thinking that it was some kind of spam...

If 20%, then 10 minutes is too long indeed.   We count on about 5k/s which for a 20% fill of a 2MB memory is equivalent to about 400kB/5k/s = 80s = 1.5 minutes. 

So for some reason it looks like the full download is done anyway.

Is the 'used memory' shown before you start the download?

Sa, 10/23/2010 - 09:14 – ps-n
Bild von ps-n

hm. when I wait 15-20 sec.

hm. when I wait 15-20 sec. after it shows "used memory" then press download it takes ~5 min. but it still work's faster on gps phototagger ~1min.

Sa, 10/23/2010 - 10:56 – mdeweerd
Bild von mdeweerd

Ok - the need to wait is

Ok - the need to wait is something that I still have to fix.

Maybe I'll have a look at what phototagger's secret is.

You can also log the serial communication to a file by activating 'GPS Connection Debug' which will write the transaction to 'gpsrawdebug.txt' and send that to me to see if there  is something to optimize (my email is in the 'about' of the application).