yashsingh1/xdaforums huggingface dataset:
[Galaxy S I9000 General] flapane:
Hooray! It worked! I went from nothing (or 1 bird or a bad accuracy and then a sudden unlock) to a full lock in about a couple of minutes.

I used a smaller wire and did a smaller welding, so the antenna now touches with the cover (ground)!

I couldn't reach an accuracy better than 10mt, however I was on the balcony, so the results on the street may be somewhat better.

That's the difference with Bluetooth external GPS and internal GPS without this fix:

Bluetooth GPS

GPS without HW fix

GPS with this HW fix

Thank you so much, my fellow citizen.

I took a 3 hours long walk this afternoon and here's a graph of the accuracy (I never lost signal holding the phone in my hand, although with BT external GPS I can even put the phone in my pocket).

This wasn't possible without this HW mod.

Another comparison:

BT gps VS integrated gps while riding my bike. They're both in a mountain bike bag, so that just a little part (where antenna is) looks directly towards the sky.

I guess you can notice by yourselves when I closed my BT GPS and enabled integrated GPS. I was curious to see if I could use it in case of an emergency (ie. dead BT GPS battery).

Left track: integrated GPS (as you can see, it's less accurated, somehow it does its job in case of emergencies) /// Right track: BT GPS
[Galaxy S I9000 General] qtekker:
Congrats! Well done!
[Galaxy S I9000 General] flapane:
:fingers-crossed:

I took a 3 hours long walk this afternoon and here's a graph of the accuracy (I never lost signal holding the phone in my hand, although with BT external GPS I can even put the phone in my pocket).

This wasn't possible without this HW mod.
[Galaxy S I9000 General] daniel_m17:
nice

thanks
[Galaxy S I9000 General] mcmanuf:
Am I totally screwed?

Guys I think I might be totally screwed.

I wanted to do method one, but i accidently removed the conductive Island as can be seen on the picture, y pulling the wire :(

Can I save the GPS somehow or is it game over? :(
[Galaxy S I9000 General] lukesan:
Ok, no real harm done.

From what I can see the island is ground. and the green you see is some protection 'paint' to avoid the copper to oxidate. There are 2 options in my point of view.

1) you can take a hobbyknife and scratch part of that paint away and then solder

2) you see that there is a coax cable below and next to it you see spots where you can solder on. You can also make these spots a bit bigger.

What I would also recommend is that you use cable that is flexible to avoid stress on the pcb etc and that you make it short!
[Galaxy S I9000 General] drdionysius:
I did a very dirty third option. I just put a nice big pointy solder-turd on it. First time I tried to close up my phone it didn't fit anymore so I scooped some solder off until it fitted. Works!

I'm a nasty boy, I know. :D
[Galaxy S I9000 General] lukesan:
I knew I wondered before about the antenna layout and contacts. Check my post in October 2011

http://xdaforums.com/showpost.php?p=18147600&postcount=347

Well I just ordered/purchased a second hand i9000 again which I should get next week (I hope)

What I did measure back then is that the 2 contacts on the back are short .... but that is electrically short.... but not for RF which GPS is.

I need to simulate the antenna structure but I think it is a sort of impedance match. So for one I do not like the step where you need to solder a wire. The impedance will change but will not match the hopefully well matched designed on paper. If you can make the wire as short as possible.
[Galaxy S I9000 General] flapane:
Yep, you were right about the rubber conductive pad.

The change of impedence was worrying me too at first, but it seems that my 3cm wire is "short" enough. It may be better, but hopefully it works.
[Galaxy S I9000 General] lukesan:
We'll see in about 2 weeks time. First thing I will do with the i9000 is put another rom on it (any hints in this jungle?) and compare it to my S2, HD2 and the ZTE blade.

Bloody GPS addiction
[Galaxy S I9000 General] skezza:
hmm, I can't imagine that the impedence would be too big but it would obviously depend on the wire. As you know, larger core, less impedance. That said, there's few things with a higher impedance than 'conductive rubber'. Rubber has impedance high in the ohms, so however they made it slightly less resistant probably made little difference.

A 3cm core wire I imagine would be safe. However, the third 'dirty' (not dirty at all imo) technique as described above with just a dollop of solder is no different to using the third non-functional contact. In fact, I'd argue it's safer because you could easily hide it if you did it cleanly. No chance of hiding the missing contact. :good:
[Galaxy S I9000 General] lukesan:
Well we are talking about HF (high frequency) electro magnetical stuff here and not electrical things. Do not mix these things up.

It's like attaching a 100 meter cable to your FM radio which receives at 100MHz. Reception will be far worse than if you attach a 75 cm long cable.

My example was at 100MHz and sats are at approx 1.2 to 1.5GHz (1200 to 1500MHz) which means that a resonant antenna will be 12 to 15 times smaller than the FM antenna.

But .... and this is in your advantage. If you close the cover the wire will not be stretched out the full lenght. In HF language that would mean that the piece of wire is shorter.

Now the larger core thing. Basically if you make an antenna wider it will have a lower Q meaning that it has a wider reception area. Also to put things in perspective, wider than it is long will not make it into a super antenna.

I could go into detail but I guess you guys would fall asleep :D
[Galaxy S I9000 General] skezza:
No no please do. This is the kind of thing we need. This fix is obviously still new and there isn't a 3 step guide.

What we need is this kind of mathematical analysis so we can judge the perfect length for the wire, the core diameter etc so this fix is perfect for everyone who implements it.

The dollop of solder would arguably work in this case too, because that would have a short length?
[Galaxy S I9000 General] lukesan:
Well a couple of factors.

I would need the i9000 back cover to check what the measurements are and then we might be able to calculate or simulate the resonant frequenty or frequenties.

As you can see from the wiki there are some on 1.175GHz and a couple up to 1.5GHz which make it that they have to make the antenna a wider strip.

Now, and this is HF, anything that is closer than 1/4 Lambda from the antenna will change its characteristics. So meaning that any obstacle (being non air) will dramatically change antenna characteristics. At 1.2GHz this means 1.2cm .... ouch ... this makes it more complex since the device is thinner than that.

Now I do like the solder bubble approach except for the fact that after a while the solder will oxidate and cause a bad contact.

I wonder why Samsung didn't place the same contact.
[Galaxy S I9000 General] skezza:
Bad design? Poor testing? Who knows. Let's be honest, they aren't the first to get GPS wrong. The only phone I've ever come across with absolutely outstanding GPS is the Nokia 5800. If you ever get your hands on one try it, you'll be amazed.

That is an excellent point about the solder bubble oxidizing and something I didn't think of, which is why we need to go through this process to find the best way. How long does solder oxidation take? It's obviously easy to clean solder oxidation but if it takes 2 - 3 years then perhaps its a risk most users would be happy to deal with then, rather than now.

Using a thin piece of wire is clearly a common choice here and to be honest, I was just going to stick a piece of wire in there and see how it goes but your points raise a lot of questions!! If not a solder bubble, what's the alternative?
[Galaxy S I9000 General] a008yc:
Someone mentioned to take the spare antenna contact out and put it on top of the rubber and use "friction" to keep it in place. Is it a good idea just to test the water? A potential risk is the contact got shake out from the rubber pad and short other wires.'

thanks
[Galaxy S I9000 General] lukesan:
wow, would never do that.

1 you still face the 'rubber' (lol) issue

2 risk of moving it during the closing of the back cover

---------- Post added at 04:15 PM ---------- Previous post was at 04:02 PM ----------

Well the 5800 looks like a brick compared to modern phones.

The antenna designs are problematic in most modern phones (iphone4 anyone?) since everyone likes metal housing and ..... it must be thin

I never tried the 5800 but I would love to compare it next to a Bluetooth GPS receiver.

Now that contact with solder. I have no idea how long it will actually take since it relies on alot of things like temperature, humidity etc.

The best thing in life that doesn't oxidize is gold. It might sound expensive but alot of things are covered with gold. I actually bet that those other contacts are gold covered.

Sometimes they sell those gold plated cinch connector cables for a couple of euro/bucks ... maybe with some pliers you could cut a piece and solder it so the top stays gold.
[Galaxy S I9000 General] skezza:
Hmm, yeah compared to modern phones but back then the 5800 was ace and kind of thin'ish :D I'll get my 5800 out tonight and do that for you. I have a very high gain Bluetooth GPS antenna that I used to use for mapping on my old Dell PDA. :cyclops: Plus, you can connect Nokias to bluetooth antennas, so I'll do the internal GPS first and the external GPS second.

The problem with gold plating is that it wears off, and the problem with gold is that you can't really melt it in your own home, or even source it in a form that is raw enough to use. However, a gold plated connector could potentially work. It sounds somewhat safer than a dump of solder but it's probably less practical.

On the internet, there is a general consensus that with enough flux, solder can be applied in a way that doesn't oxidize. That said, if soldering isn't practical either we could do with a wire solution that is mathematically correct.

With a cable of 1.2cm, frequencies of 1.2Ghz would be picked up yes? Would thi be enough for GPS?
[Galaxy S I9000 General] Kristi-Tech:
Here is what I did to fix GPS on my i9000. As you see, the 2 antenna connections are removed and replaced with "solder bumps". The U shape plate was broken by accident so I had to remove it completely.

After applying the solder I adjusted their high for a better contact with antenna. Tested GPS signal and I was amazed how fast it locks. Also the signal is strong now! Very happy with it :D

[YOUTUBE]<iframe width="640" height="360" src="http://www.youtube.com/embed/SS-PWBIt_O8?feature=player_detailpage" frameborder="0" allowfullscreen></iframe>[/YOUTUBE]

http://www.youtube.com/watch?v=SS-PWBIt_O8&feature=g-upl
[Galaxy S I9000 General] mcmanuf:
1) I didn't scratch anything away(dont dare to use a knife as my motoristic skills are obviusly limited), but whenever I try to use a dollarop of solder it simply do not stick. It falls off if I push. So what I did was to solder on the cover instead,as the conductive point is intact there. I then try to match the height (~2mm) of the other metal contact and hope for the best.

2) Not quite sure which coax cable you are refering to. Could you please take a picture or maybe point it out on my picture with some red circles or something.

BTW, if there is no contact between the two points what will happen with the GPS.

Will I not be able to recieve anything at all, or will it correspond to the situation with the rubber band where there is no contact?

Because at the moment I am not sure if my solution works or not, as the reception is still sh..., but I am able to find sattelites in clear sky. I just lose them again if I move around with the phone.
[Galaxy S I9000 General] lcampori:
you guys are the engineers, so I would never dare contradict.

that said, 2- that was my main worry as well, so by taking advantage of the u-shape of the golden contact (the one unused and removed) I found the way to secure it firmly on top of the so-called 'rubber'-(lol). since you're fighting against my self-esteem ;) I'm not telling how I did that. I already find myself dumb enough. just a matter of some plastic and glue.

that said, 1- by placing that golden contact on top of the so-called 'rubber'-(lol), I'm getting astonishing results. By astonishing I mean get an instant lock and, moreover, the noise to signal ratio is ... well you find the word: in clear sky conditions, I've been able to lock 11 sats, 6 of them with n/s ratio above 42. for the sake of it, I tried ten minutes ago and locked 8 birds, 4 of them > 40, 2 at 37 one 35.

that said, (final) I trust you guys much more than myself, so hopefully you'll find a robust way to overcome the issue. I do not know where the problem lies, but by Occam's razor, I'd say it is not because of that little 'rubber'-(lol) piece.
[Galaxy S I9000 General] lukesan:
Your rubber :) works amazing. If you get these numbers don't touch it anymore. According to me you have a more than perfect match and you should bring your rubber in production (unused that is!)

Yup, now that is the way it should be!

You removed the island, it can and has happened to the best of us, no worries. I have messed up some pretty expensive stuff myself.

Ok now the solder part. Now these days, thx Al Gore for not really liking you now, they use ROHS ... no lead in the solder so this has a couple of major dissadvantages. Lead is a bit flexible and sticks pretty well. So devices that get hot and are prown to vibrations (a phone anyone) have solder issues. Google 'rebaling bga' and you know what I mean.

..... Almost lost what I was about to say..... you need flux, the proper solder and a nice station to do this.

I don't have the i9000 yet so looking at your photo I can not see how the paths runs. Maybe if some other gentleman (or woman) can have a look on how it runs on the board we would be grateful.

I did the test with a 5cm wire (a bit less than 2 inch) just connected to the golden spring. As long as you keep that wire away from the phone you will get results like other gentlemen with the working antenna. Ofcourse that test was conducted without the backcover and is unusable.

We will get it running for you no worries, just a little patience (I know not my strongest point at all myself)

Btw I think still have one of Sony nautical gps receivers that I used back in the 90's. I believe like 8 or 10 AA batts (empty before you know it) and a locktime of like 10min.

Looking fwd to that test with the 5800, but which program shows the SNR?

Now the gold plating. There shouldn't be any friction so I don't see how it would wear off actually.

I think I know of a bit of other temp solution . Google 'ic socket' and you will see examples of sockets that use springlike mechanical solutions. Any electronic shop sells those and you could easily get them out and cut and solder them

Now that 1.2cm antenna.... wait the construction of this thing is a bit different than the standard 1/4 dipole. The 'rubber' contact is actually electrically connected to the ground as far as I can see and it is an electrical short with the 'antenna spring contact' that is default on it. I would keep it as close to the design (as intended by the engineer who drew it) as possible.
[Galaxy S I9000 General] the-weatherman:
My little contribution to this topic: I have successfully revived my GPS using the second trick, and it works damn great! Instead of unsoldering the connector I have used another one from an old Nokia.

Thanks a lot sir!

sent from XDA app
[Galaxy S I9000 General] fran_xda:
Hi,

This is my experience with the fix. I have finally solder 2 wires, one for each connection (long story, but I would have used just 1 wire). I took them from a RC helicopter toy, very thin and just paint coated. I needed to open the phone twice because the first time I made the fix I eventually lost all the signal. I think that in a similar way to the case of mcmanuf the conection to the ground was weakened during the soldering although it seemed to be Ok. The important thing is that now the Gps locks in seconds! Thank you for the fix!

Actually I decided to write to post an idea, similar to Icampori aproach I think. How about using a layer of conductive paste on top of the rubber? I am thinking of something like the thermal grease used in computers. I think that some of them contain silver and they are even dangerous to apply for being electrically conductive.
[Galaxy S I9000 General] lcampori:
indeed.

it works so great that I had to adopt my daughter :)
[Galaxy S I9000 General] skezza:
Did this fix today.

Unfortunately for me, I don't think it's made it better. It may have made it worse but tbh, the GPS was borderline unusable for anything other than driving anyway so I'm not exactly crying a river.

The problem i'm having is that it sees the satellites, locks, then it seems to lose the lock very quickly. I've noticed this a number of times. In fact, when it does lock, it gets numbers in the 30< range, but it seems to lose the lock almost instantaneous. Especially when I'm moving :( I tried to use a short piece of wire and I used thin wire too.

Nice idea, didn't' work for me I'm afraid. GPS isn't a massive deal breaker for me, it's just useful to have.
[Galaxy S I9000 General] elitevet:
Where, geographically, are you?

sent from CM10 powered SGS
[Galaxy S I9000 General] skezza:
UK
[Galaxy S I9000 General] elitevet:
Might be trivial but worth checking, in your gps.conf there is a setting for NTP server your phone tries to use, check this is the right, UK based server. Also, don't blindly count on ntp.org pools, there might be no servers inside an existing pool, like the case is here in IL. Check with your country's Internet Authority whether they provide an NTP service

Also, cloudy and moist is not the best conditions for GPS. How's the weather on the Island?

sent from CM10 powered SGS
[Galaxy S I9000 General] flapane:
I ALWAYS experience this on the FIRST cold lock in the first couple of minutes. It happens two or three times, and then I get a solid lock. I'd double-check the solderings.

Oh my :rolleyes:

Unfortunately it's not famous for its sunshine.
[Galaxy S I9000 General] Kagoo:
Wow that's incredible !!

I had a lot of trouble to do it, but know it works great !

First I tried with a wire, and my gps was dead, absolutely no signal, and the plastic around the antenna melted due the heat of the iron solder. Then I tried with the unused connector, and I did a really bad soldering and so no gps at all. Finally, I removed it and made a "bubble", then opened a bit the connector close to it to improve the contact too.

And know I have 9 satellites with SNR > 30 !!!! On Gmaps, fix is really fast, with a 5 meters accuracy :)

Thanks a lot !!!
[Galaxy S I9000 General] lukesan:
Well I`m not so impressed by ntp stuff. To me the only thing it should do is to decrease the locktime. Lets say that this agps thing which relies on the calculation between the ntp servertime and sat position only gives you a fast fix. Oldtimers like me remember the times without agps, like BT gps devices which do not have any network connection. Once it has a lock it has a lock period. The time to obtain one is longer, like 30sec to a couple of minutes. If I`m going abroad I don't have data but still get excellent gps reception.

Now I see all those people using a thin wire, why don't we strip a piece of antenna coax and use the outer ground shielding. We should be able to solder it on the pcb standing up so when you close the cover it makes contact
[Galaxy S I9000 General] <<Raj$>>:
Fantastic, spot on.

I have used the first solution and it's spot on.

Thanks for the finding leeno.
[Galaxy S I9000 General] skezza:
OK tried it last night. Clear night, no rain. Locked after a minute or two and to be fair, didn't lose lock all the way home. Was definitely usable so that's a positive.

Tried it this morning, heavy thick cloud and rain, locked but was iffy. I'll check the solderings tonight, but the guy who did it is a professional, I mean, his soldering skills are exceptionally good.

We used special enamel coated copper wire to allow it to get back into the phone easily. It's thin of course, but I thought we'd come to the agreement that thicker might NOT be better. I'll take a picture later for everyone to see.

At lunch I'll install the sports tracker app and see how well it tracks me going back to my car and then back to work.
[Galaxy S I9000 General] lukesan:
I would suggest you download 'GPS test' that way you can see what kind of SNR's you are getting. Lets say that anything above 30 is more than nice. In the 40's is ... wow

Now as the sats move position these numbers will change both in SNR as the amount of sats you see and get a lock on. I've had days where I had locks on 12 sats and other days on 7.
[Galaxy S I9000 General] skezza:
I've tried GPS Test, i usually get under 30 although I'll get the odd satellite over 30. Some satellites are in the 20s and some in the 10s but that's just approximately.

It's a fairly clear day outside so i'll give it a try with sports tracker. Not sure what I did wrong exactly, do you think the wire I used is too thin?
[Galaxy S I9000 General] lukesan:
Actually hard to tell. Could also be the receiver itself that is not so great.

It could also be the cover which holds the antennas which could be the problem.

If you are a bit adventurous and want to test you could try to connect a piece of wire to the top contact (the spring type one). Make it like approx 5cm or 2inches and leave the cover off. It's a bit tricky but you can hold the batt and keep the wire like 90 degrees away from the pcb.

When you go outside you should have excellent reception.

As a wire you could strip a rj45 network cable. These wires are thin enough most of the time (and cheap).
[Galaxy S I9000 General] skezza:
Hmm, I might have the phone apart again later and see what I can do. Perhaps this is as good as it gets.

I gave the sports tracker app a go, it got a lock pretty quick to be fair and it did monitor my route 'fairly' accurately. Certainly not accurate enough for a phone as good as the SGS, but passable. It will probably work with most of the navigation software but I doubt it'll be good for stuff like walking directions.

The wire i used was about 2cm long I reckon. I will take a photo later and show you.
[Galaxy S I9000 General] a008yc:
I haven't crack open mine yet as mine is still under warranty. But you should able to use a multimeter to check the resistance to see if the rubber contact is the issue. If you get fast fix just by layer the contact on top of the rubber, maybe the problem was the rubber didn't not have physical contact with the antenna?

Speaking of my T959D, it took a few minutes to get a GPS fix indoor, sitting next to a window, I got accuracy of 16ft to 33ft. 6 feet away from window, I got 33-98, sometimes 16 feet. 12 feet away from windows, accuracy fixed at 98 feet. Is my signal acceptable even without mod?

thanks.
[Galaxy S I9000 General] lcampori:
yes, that was my first thought as well, but I did not check because I have no multimeter.
[Galaxy S I9000 General] skezza:
Here's a picture.

I've tried something, i'll let you know if it works in the next hour. I'm not getting my hopes up though.
[Android Software/Hacking General [Developers Only]] Phr3d13:
Anyone working on an Odin image or cwm flashable zip?

Sent from my Conquered Conquer 4g
[Android Software/Hacking General [Developers Only]] weasel4ami:
I am also looking for Odin image of fe16. Right now IM rooted fc17. Just need to find update.zip file.

ok got stock fc17 Tar files, and now im stock fe16... now I need to find out how to root. n e ideas?
[Sony Xperia P, U, Sola, Go] nemer12:
How can I find out if I have a locked bootloadeR?

What's the difference bewtween Locked bootloader ?! and unlocked one ??

and the restrictions .!?