Reason for GPS problems found!

Konstantin Chaosspawn23 at
Tue Jul 15 13:05:35 CEST 2008

thomasg wrote:
> Hi ppl,
> I write this to community, not to devel or owners because everyone
> should know:
> _sbeh_, one of the people in #neo1973-germany IRC-channel found the
> reason for the GPS problems.
> The problem only occurs if a SD card is set in. Doesn't matter if it's
> mounted or in use, it just has to sit in the socket.
> The TTFF went from no fix at all to TTFF 120 seconds indoor(!!!), and
> about 40 seconds outdoor.
> Two other people could verify this with about the same results.
> We'll do more tests later, but for now we surely know what's causing the
> problem (and it seems to be a EMC problem).
> First results show at the same devices, even outdoor, that there is no
> fix in over 400 seconds with SD card, the signal seems to be at least 10
> to 20 dB worse (so bad, that most satellites don't even appear).
> Testresults from other people appreciated.
> thomasg

I think I can confirm this. I never got a fix with the internal antenna before -
Now, having removed the microsd card and holding the freerunner out of the
window, AGPSUI got the GPS time after ~18s, and TTFF was 111s. Amazing!
Now, how do we fix that? ;)


More information about the community mailing list