Reason for GPS problems found!

Torfinn Ingolfsen tingox at
Tue Jul 15 17:27:32 CEST 2008


On Tue, Jul 15, 2008 at 12:42 PM, thomasg <thomas at> wrote:
> 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).

Why does people seem to think it's an EMC problem? Ill hazard a guess
here (and I haven't even seen the schematics for the device); it is
probably a voltage or current problem. When the SD card is in, it
draws power, causing the voltage to something in the GSM circuit (for
example, the antenna selctor circuit) to change. Or current.

> Testresults from other people appreciated.

Well, I am currently inside (it's raining), but on the SS screen of
openmoko-agpsui I now have 13 (yes, thirteen) blue bars, most of them
above 150 dBm. Before (with the SD card in) I never even had one blue
bar on the ss screen.

Great work discovering this.
Torfinn Ingolfsen,

More information about the community mailing list