<HTML dir=ltr><HEAD><TITLE>GPS issues on GTA02v4</TITLE>
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<DIV dir=ltr><FONT color=#000000>Dear Daneil:</FONT></DIV>
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<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN lang=EN-US>I am the hardware engineer dedicate to RF parts. After reading your statement about this issue, this issue may be caused by bad connection of internal GSP antenna. Some tests should be performed on your Neo. I will also send you two antennas. One is internal and the other one is external. </SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN lang=EN-US>1. Replace the new one on your Neo and check signal quality (In open-sky, the TTFF is less than 45s)</SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN lang=EN-US>If the result follows my expectation, the reason for this issue may be repeat de-assembling to damage the RF cable of the internal GPS antenna. </SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN lang=EN-US>If not, I think you can do the next test </SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN lang=EN-US>2. Plug the external antenna in our Neo and check the signal quality </SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN lang=EN-US>If the GPS is normal, I think the RF switch circuit (ESD sensitive) is complete break-down. </SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN lang=EN-US>If the signal is still poor or the Neo can not get any satellite, the Neo you owned should be call backed and fix it. (GPS chips must be something wrong)</SPAN></P>
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<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN lang=EN-US>I will send you these two antenna as soon as possible. If any question, let’s discuss together. </SPAN></P>
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<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN lang=EN-US>Best regards, Shawn</SPAN></P></DIV>
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<FONT face=新細明體 size=2><B>From:</B> openmoko-kernel-bounces@lists.openmoko.org 代理 Daniel Willmann<BR><B>Sent:</B> 2008/3/4 [星期二] 上午 07:06<BR><B>To:</B> openmoko-kernel@lists.openmoko.org<BR><B>Cc:</B> DKAY_CHEN [陳南廷]; TIM_LEE (李國平經理); ALLEN_CHANG (張吉隆)<BR><B>Subject:</B> GPS issues on GTA02v4<BR></FONT><BR></DIV>
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<P><FONT size=2>This mail is mainly an FYI if some GPS related issues creep in along the<BR>road. My problems are probably caused by poor SMT during the GTA02v4<BR>run.<BR><BR>See also<BR><A href="http://lists.openmoko.org/pipermail/openmoko-devel/2008-February/001981.html">http://lists.openmoko.org/pipermail/openmoko-devel/2008-February/001981.html</A><BR>for my problem report earlier.<BR><BR>I first really tested GPS on my 2v4 on the train ride from FOSDEM where<BR>the GPS managed to get a pretty good fix even through the window of the<BR>ICE (the navilock GPS receiver I tried didn't).<BR>A couple days later I was again travelling by train and this time the<BR>Neo wouldn't even acquire the time. When I tried again at home the<BR>result was still the same, no fix, no satellites, no time.<BR>I played around with the connector of the internal GPS antenna,<BR>applying pressure, and the GPS managed to get the time and see some<BR>satellites for a short time, but that was it. After that I wasn't able<BR>to reproduce any positive results with the internal antenna anymore (I<BR>also tried different antennas). Attaching an external antenna worked<BR>however and I was able to get the time in ~20s and a fix in additional<BR>20s so GPS itself still seems to work.<BR><BR>At the moment I'm suspecting that either the phantom voltage for the<BR>internal antenna or the antenna switcher is broken.<BR><BR>Regards,<BR>Daniel Willmann<BR></FONT></P></DIV></BODY></HTML>