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GPS Locking Issue

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By Jerry1130, Junior Member on 15th October 2013, 07:32 PM
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4th December 2013, 05:37 AM |#71  
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I tried your solution, it is better, but once it lost signal, it just won't reacquire again. However, I was able to manage a 30 minute commute over highway and maintain signal on a cloudy night. So looks like the TopNTP customized conf.gps does help as I notice the delta from the stock file.
4th December 2013, 07:37 AM |#72  
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Quote:
Originally Posted by obladi64

... and now?

I'm not sure. Just trying to get as much info as possible and see if we can make sense of it here and find the culprit.

Sent from my VS980 4G using Tapatalk
4th December 2013, 04:00 PM |#73  
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Quote:
Originally Posted by MoNsTeReNeRgY22

I'm not sure. Just trying to get as much info as possible and see if we can make sense of it here and find the culprit.

Sent from my VS980 4G using Tapatalk

So I think that my opinion what I wrote here earlier is valid. This could be signal strength issue. Check chinyuk's comment too. All software solution is for getting satellites' positions quickly. It helps identifying satellites from internet instead of from satellite but anyway GPS service or function or whatever we call it is not better significantly. If someone's phone sensor or antenna is more sensitive a bit can use navigation without or with rare unrecognized problem. If sensitivity would be high enough phone can get data from satellites too very quickly as a standalone GPS System.

For more info look at this thread.
http://forum.xda-developers.com/show....php?t=2063295

The solution is linked there.
http://forum.xda-developers.com/show....php?t=1318892

I do NOT encourage anybody to do it without hesitation but if someone already did it on G2 or any other please share the experiences.
5th December 2013, 10:56 PM |#74  
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Not so many comments. OK I did some research on Youtube and reason is very clear. It is because of the antenna. More precisely the lack of the antenna.
Look at the inside picture of LG G2 and Samsung GS4. Ther is nothing between the contacts. Well would it be so expensive?
Anyway I will to fix it later. Firstly I need the appropriate tools for opening the back cover without any damage. You too can find few videos how to disassemble the phone.

I suggest to watch this in any case although the quality is not HD.
http://www.youtube.com/watch?v=ZxwpLiKTtXU

If anyone did this mod don't hesitate to share the result.

Warning! If you don't have enough experience in repairing electric devices do not try to do it alone.
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6th December 2013, 07:50 PM |#75  
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Quote:
Originally Posted by obladi64

Not so many comments. OK I did some research on Youtube and reason is very clear. It is because of the antenna. More precisely the lack of the antenna.
Look at the inside picture of LG G2 and Samsung GS4. Ther is nothing between the contacts. Well would it be so expensive?
Anyway I will to fix it later. Firstly I need the appropriate tools for opening the back cover without any damage. You too can find few videos how to disassemble the phone.

I suggest to watch this in any case although the quality is not HD.
http://www.youtube.com/watch?v=ZxwpLiKTtXU

If anyone did this mod don't hesitate to share the result.

Warning! If you don't have enough experience in repairing electric devices do not try to do it alone.

Honestly, if I had to go to that extent to fix it, it is pretty sad. I am a pretty hands on guy but I can tell you that it is not as easy as in the video to ply open the shell. I recall a while back, I tried to replace my iPod Classic as the battery is dead. Bought the battery that came with the pliers but no matter how hard I try, it won't budge. Looks easy in video but not that easy. I assume if you had the official right too, it is probably not that bad.

I am starting to give up on this and hope a software patch will help with this problem. It is strictly from experience with no evidence, I recall in my Galaxy S3, the GPS was working like a charm for a long time but I went from ROM to ROM. I came across one ROM that was very weak in locking GPS and took forever and just won't lock the signal well. I imagine it could be driver related. Obviously, as you pointed out, the hardware design is flawed in the first place and I imagine with the # of Nexus 5 complainers out there as well, there is a handful of the G2/Nexus 5 that suffer the same problem. I mean, the design might work "just good" enough if the assembly was done picture perfect but if you are off, much like any antenna, the SNR will degrade drastically. My hope is that there is someway to help reception but I think it is a long shot cause if a hardware design is bad, no much you can do on software side cause this is the receiver and not the transmitter. For transmitter, if you boost the signal level, it will help, for receiving, it is how best you design you antenna and LG is just poor with this. Oh well. On some days, it is livable but I imagine driving downtown with too many building blocking forget it, you are totally SOL. Driving to work this morning, I was okay on the highway most of the time but as soon as I exit and there were condo blocking mostly the left side of my car, signal when dead. It's just plain annoying. I think this is a pretty hot sell device and I am still surprise if this is a common problem we don't get more rants in this forum about it, oh well, have to see if I can get an exchange for my phone.

---------- Post added at 02:50 PM ---------- Previous post was at 02:35 PM ----------

Guys, did you check out this video:

https://www.youtube.com/watch?v=K1-u...e_gdata_player

Looking at the video and obladi64's picture of the internal of the G2, they look very similar. I have reason to believe that the Nexus 5 solution would also solve the problem with the LG G2 as well and might explain why some people are okay while others are not as it is probably assembly related.

I guess for those that dare to void their warranty and give this approach a try, it looks very promising.

Also, check out the Nexus 5 GPS issue forum as well, it seemed there are more than 1 success story.

http://productforums.google.com/foru...1-225-false%5D
6th December 2013, 10:47 PM |#76  
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Quote:
Originally Posted by chinyuk

[/COLOR]Guys, did you check out this video:

https://www.youtube.com/watch?v=K1-u...e_gdata_player

Looking at the video and obladi64's picture of the internal of the G2, they look very similar. I have reason to believe that the Nexus 5 solution would also solve the problem with the LG G2 as well and might explain why some people are okay while others are not as it is probably assembly related.

I guess for those that dare to void their warranty and give this approach a try, it looks very promising.

Also, check out the Nexus 5 GPS issue forum as well, it seemed there are more than 1 success story.

http://productforums.google.com/foru...1-225-false%5D

Chinyuk, you are right, it is not so easy as it looks like on the video and nobody do not try it without enough experience.
But. I have bad news. Despite the difficulty there is no any other way to fix the problem. Nexus is not G2 although both are from LG. There is no antenna at all on the backside of the cover. See the picture. Same as HTC. Only the big stink mothing. See attached photo.
So if everything goes as planed may be I'll try to solder antenna there on Sunday.
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7th December 2013, 02:16 AM |#77  
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I have decided to post my observations.
I own LG G2 - 803. It is second instance, first one replaced with faulty battery. GPS behave similar in both. Sometimes it works very well compare to my old Galaxy S2 and comparably with Nexus 7. But sometimes it is very bad - signal is low and only few sat in view and no lock.

Initially I thought that somehow it is related to internal temperature, but after testing I think it is doesn't impact.
Second observation that sometimes after tossing it in hand it start or stop to work properly, so probably some issues with physical contact.

Other observation that if it works well, with clear sky it locks to 15-16 sats, after few seconds locking drops to 9. After close look I have figure out that when error reach 4-5m, it switch to 9 sats, so I think it is some kind of battery saving technic and I am ok with this.

Finally, yesterday it failed to lock successfully with clear view in my car. I have decided that it is time to fix it. After close look of service manual, I have found that antenna located in back cover and may not have good contact with main PCB.

So I decided to remove back cover and see what can be done for this.

So:
1. Remove back-cover (easy) and no damage.
2. Clean antenna contact with vodka (I don't have anything other) on backcover.
3. Spring contacts for gps antenna pushed a lit a bit up.
4. Assemble.

After initial test, signal and number of sats looks very good. Let's see how it will behave over time.
7th December 2013, 02:32 AM |#78  
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I try to attach the picture once more.

Update

It does not work either.
7th December 2013, 08:05 AM |#79  
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Quote:
Originally Posted by obladi64

Chinyuk, you are right, it is not so easy as it looks like on the video and nobody do not try it without enough experience.
But. I have bad news. Despite the difficulty there is no any other way to fix the problem. Nexus is not G2 although both are from LG. There is no antenna at all on the backside of the cover. See the picture. Same as HTC. Only the big stink mothing. See attached photo.
So if everything goes as planed may be I'll try to solder antenna there on Sunday.

Are you sure about this, I am looking at this YouTube Video, and it seemed to me it has the same contact as the Nexus 5

http://www.youtube.com/watch?v=Z8vVGC6z2Lk

Goto the 3:45 mark of the video and if you look at the cover, the bottom right corner has 2 square contact. I believe that's the contact for the GPS antenna as this matches the same area where you show the GPS location in your picture. I mean, it is the opposite side to the flash so that's how I correlate. I am very interested in trying the Nexus 5 fix, I have a feeling but making the contact touch better, it should help the reception. Also, I am not sure about your last respond, what did you try?

---------- Post added at 03:05 AM ---------- Previous post was at 02:26 AM ----------

I can report one more observation playing around with the phone tonight on my way home. I have a car charger (sort of a phone holder + charger) and I found this rather odd behavior which might further proves my theory about the antenna gap between the contact.

What I did initially is have the phone with no charger connected, it took time but GPS finally connected properly despite a relatively weak signal that give you accuracy in the neighborhood of 12~15m, not great, but hardly do you see single digit. As soon as I plug in the car charger, the thing just went totally dead, no GPS lock and relies on network lock 800~1000m in a matter of seconds. Unplug the thing, and in a matter of seconds, it seemed to get lock again. I tried that 3 times and it happen all 3 times.

My conclusion for this is the charger connector when plug in ever so slightly increase the air gap between the antenna and the contact from the phone PCB side. It's like your are trying to squish a bit more air gap when the connector is connected. Taking it our restore the original air gap. So my guess is that the decrease of the air gap could potentially solve the problem.

I probably need to go try to get the tool myself, I have seen several video and with the right tool, it might not be too hard to ply open the case as the sim slot gives a starting spot to ply it open. I had a difficult time trying to do that with my iPod way back when cause I don't even know where to start.

Hopefully, one can try this out and see if it helps, They use manila paper to decrease the air gap but pushing the back cover and lifting the contact there toward the phone PCB. I think it should improve it. My guess is currently, there is an slight air gap and we all know that even with the air gap, you can still get some form of reception. Think of the good old FM radio and how reception is weaker with the antenna retracted vs fully extended. I believe the idea is similar.

To me, as long as you are not touch the PCB side and doing anything on that side, the risk should be low, worst that can happen is one of the latch breaks off. Since this isn't a waterproof phone (e.g. Xperia Z1, it doesn't matter that much). I hope someone can give a try, I will see if I can get these tools at a surplus place tomorrow and report back if I can either 1) fix the problem or 2) break my phone
7th December 2013, 09:53 AM |#80  
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Quote:
Originally Posted by chinyuk

Also, I am not sure about your last respond, what did you try?

I tried to attach picture unsuccessfully. I did attempt by using Chrome and Firefox too but I could not. This is not the first time that it happens with me on this forum but anyway it is not important now.

The picture would have shown that no antenna is on backside of the cover. But I supposed that antenna is on the second inside cover. OK I see that it can be stuck onto the outside back-cover. That is good. At least LG tried.
Anyway this fact does not change the point. Hardware fix is required and we should disassemble the device. May be warranty won't loose if Nexus fix can be applied here but I am not sure in it.

Regarding the charger issue. It is interesting. Root-cause can be what you mentioned but rather it is electric problem. I will check my phone how it behaves on car charger.

Also I am waiting for you mod experience if you did once. Please take a screenshot with AndroiTS before and after like on this video.

http://www.youtube.com/watch?v=mXjflYWOF30

If LG screen shows same as of Samsung means that fix is cool.
7th December 2013, 02:25 PM |#81  
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Ok, so far so good. GPS works well after hardware fix.
It is very easy to disassemble (remove backcover). I just removed simcard and used my tails to pull up the backcover. Instead of recomended clockwise direction, I went in opposite way. Unfortunately no picture from inside.

GPS antenna sticked to backcover. Same with NFC antenna. There are 2 more contacts for other antennas, but I was unable to figure out their purpose (it is not Wifi-BT).
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