Reason for GPS problems found!

Simon Matthews s.matthews at
Wed Jul 16 02:39:06 CEST 2008

I would like to know if the SD card noise is desensitising the external
antenna as well.

This would point to noise getting into the antenna mux and front end of
the GPS circuit.


On Tue, 2008-07-15 at 23:29 +0200, Joerg Reisenweber wrote:

> So we can assume this is pretty confirmed by quite some reports now.
> Thanks to community for the awesome help on this!
> Special thanks to *sbeh* for finding this. Please mail me directly ;-)!!
> We did quite some tests on this as fast as we could (and I never assumed we 
> could be *that* fast), and it seems we found the root cause of the problem.
> ALL THIS IS PRELIMINARY INFO! Due to further tests to confirm.
> Just to let you all know we're on it, and please stop thinking about shielding 
> the SDcard with tin foil or relocating internal gps-antenna. It won't 
> probably help.
> The good news: *IF* all pans out, there's (or soon will be) a new kernel at 
> Andy branch that stops SD-card clock when SDcard is idle. We hope this will 
> almost cure the problem, at least reduce it to sth like "you can't GPS while 
> watching video from SD" or the like (hope you can cope with that ;).
> We're about to verify a hw-fix so you could even watch video and still have 
> GPS positioning during that.
> Please stay tuned and be patient, we'll come up with news *really soon*.
> And *please* don't try weird reworks and maybe break your FR by doing so 
> ;-) ;-) ;-) ;-) ;-) ;-) ;-) ;-) ;-) ;-) ;-) ;-) ;-) ;-) ;-) ;-) ;-) 
> cheers
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