Reason for GPS problems found!

ian douglas ian.douglas at
Tue Jul 15 17:37:11 CEST 2008

For those that follow the devel and commitlog lists, there was a patch 
submitted by Andy Green @ Openmoko on the 13th suggesting that an 
increase in voltage to the GPS workings might help. I haven't tried this 

The note attached said:
"GPS internal antenna issue appears to respond positively to cranking 
RF_3V to 3.6V from 3.0V."

Perhaps Torfinn's last Email was right: it may not be an EMC problem but 
a lack of voltage?


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
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