yashsingh1/xdaforums huggingface dataset:
[Captivate General] amish_captivate:
What is interesting is that just removing the rear cover alone seems to make a huge impact on GPS reception. I just tried a test both with Google Maps and GPS Status both from inside my house were I have never got the GPS to lock. I started the GPS status with the rear cover ON. Couldnt get a lock. With the GPS Status running I removed the rear cover. Instant Lock 9/9. I then replaced the rear cover and GPS status reported 0/8.
[Captivate General] jz3:
Yes, I discovered this too and is what lead me on to the contact issue. I believe with the contacts fixed, the cover acts as part of the antenna allowing the signal to pass through instead of blocking it.
[Captivate General] Jeffu:
This is pretty amazing. I like most others here experience insanely better lock without the cover, and after scraping and prying a bit it's still decent with the cover on.

Now I just need to have no more random shut downs and this phone will be perfect!
[Captivate General] acdbx:
Is removing the cover equivalent to scraping the contact?

If removing the cover provides no benefit, can we say that scraping also won't help?
[Captivate General] Ben74:
Another success. Although, I didn't find any improvement with the cover off. Zero sats with or without the cover indoors. 8 sats indoors after scraping the contacts, and went from 3 to 4 bars. Speed test didn't improve much, but I think that's because my speed was already pretty good. Thanks OP! Amazing that Samsung's epic GPS fail was due to such a simple manufacturing mistake.
[Captivate General] phatninja13:
After trying other various improvements I updated to Cog2.3b8 and then tried this fix. GPS and cell signal have greatly improved. I couldn't get a signal at all in some areas here in lake charles,LA and now I get a lock 90% of the time in under a minute and stays locked while driving. I still have some trouble getting the initial lock while driving but as long as I get one while stationary this seems to have drastically improved it. But as with the other fixes ill check back in a few days to see if its still working. But so far 3 days after this fix it seems to be greatly improved =D
[Captivate General] ewingr:
Yep. Interesting. I posted in this thead at post 22 about the same am thing. Doesn't seem many have read or paid any attention.

I am using an Seido Innocase, so it effectively covers my phone and so I have removed the Captivate's metal back. iMy GPS works quite well.

Its also interesting that it seems many are finding the suggestion at the OP to improve GPS performance. I found that even with doing that, and putting the back on, it is not as good as having the back off.
[Captivate General] Jeffu:
For those with consistent improved performance, could you post your GPS settings? I seem to have issues locking again, and I think I might have changed something or lost a change on reboot.

edit: hmm, yeah. now I can't get ANY lock. this isn't good D: maybe I scraped too much?

edit 2: It's consistently having a problem also without the cover off... and I haven't done anything more than scrape most of the white off and pry the contact up a bit. I wonder what changed.
[Captivate General] oriongaby:
I can't believe this really helped, now im getting 4 bars of signal in the same place I only used to get 2 before.

And the GPS improoved too, I couldn't initially get a lock inside my room but I walked outside and it found 7 satelites in less than 10 seconds and when I walked back to my room it didn't loose the GPS signal like before.
[Captivate General] mchimney:
Well, i essentially live in a cinderblock cell (dorm room) and i sit about 8-10 feet away from the closest window. Normally i have full cell service so i couldn't really test that, but in previous attempts to find a gps this far indoors has failed up until now. I only took the back cover off and i'm now finding satellites (although no locks) but i'm pretty happy with the results.

I will test this outside once it warms up a little haha, but it's good to see that everyone is still finding ways to make this gps better.

P.S. Does the inside/ screen of anyone else's phone smell really really bad?

*edit* i just put the case back on and im still finding those same satellites, weird
[Captivate General] evoic:
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

This.
[Captivate General] SolidMetal:
^ This. Can someone please post up step-by-step images and explaining things more in-depth? I'd hate to muck up my new toy!

I mean, I think I understand about the white contacts. But how much are we to scrape off or "erase?" Also, what about the copper part bit? Bit confused by that one. :confused:
[Captivate General] amish_captivate:
Missed your post. Sorry. Anyway I am using a Body Glove case so I am also going to experiment with leaving he rear cover off. It is nice that the rear cover latch holds the battery in place with the cover off.
[Captivate General] chinesedevil:
The copper bit is like a little spring, just poke a pin under and raise it gently and lightly just so it sits a bit higher than its normal position. I noticed drastic difference without scraping and just by lifting that copper contact, I did scrape the white stuff a bit till it was silver (its a very thin layer). Good luck. I don't have enough posts to put up an image, :/
[Captivate General] qwertyaas:
See pics from earlier post.
[Captivate General] FredWorrell:
Seems better

I scraped the contact points and lifted the contact and I can say that I do see some improvement. I've had satellite signal as high as 47 where I was only getting about 38. Also, walking seems to keep all satellites in the low 30's to high 40's where it was no where close to that before. Thanks a bunch.
[Captivate General] r3ferrei:
Lifted the top right spring so it would make better contact and I got a gps lock in a few seconds indoors where I wouldn't before. No improvement in data.

Fantastic discovery.

Sent by an Assonance.
[Captivate General] superdog404:
I have also seen an improvement after scraping and raising the clip. I have never seen 11 sat. and locked on 8. It is raining so very cloudy here. Great job jz3!
[Captivate General] oriongaby:
Smells like new!

EDIT: I'd post some picks of the procedure but my camera's LCD stopped working :(
[Captivate General] Jeffu:
Argh, haven't figured out what I did wrong! I experienced the improvement in lock time, scraped a bit more, bent the metal bit a little bit ... and now it almost never gets a lock. Removing the back doesn't change anything, so maybe the satellites just ... decided to mess with me? :(
[Captivate General] oriongaby:
Managed to snap a few pics with the broken camera. :cool:

Remember: be careful when you pry it up, don't break it.
[Captivate General] a.vandelay:
is this a permanent fix? obviously everyone is rebooting their phone to do this mod, and GPS always works well when you reboot, but then degrades over the next day or two. how's it holding up?
[Captivate General] nybmx:
So far for me this has not produced great results. I tried just using an eraser and prying the clip up. Then I tried being more aggressive and scratching the white areas a bit. Here are my results.

With back cover removed:

Found 7 satellites in 5 seconds.

Found 10 within 20 seconds.

First accuracy was 100 meters at 73 seconds

Locked on to 4 satellites ~5 seconds after first accuracy.

With back cover and body glove case:

Found 1-2 satellites in first 10 seconds.

For first minute kept finding X then dropping to X-1. (Ex: Seeing 3 then instantly dropping to 2, repeating this until it found 4 then instantly dropping to 3....and so on).

First accuracy was 200 meters at 78 seconds.

No lock within ~20 seconds after first accuracy.

For both of these tests I deleted GPS data first. Stood in an open area with the phone facing upright. Mostly clear night, very minimal amount of clouds.

Phone info:

Perception build 4.

JK4 Modem

Not overclocked.

Undervolt settings:

100Mhz = -125

200Mhz = -125

400Mhz = -100

800Mhz = -75

1000Mhz = -75

1200Mhz = -50 (although since I disabled overclock this shouldn't matter)
[Captivate General] nybmx:
You don't have to reboot. And people noticed better, but degrading, performance when they flash a new rom, not when they reboot.
[Captivate General] oriongaby:
It helped with my phone signal strenght so I'm sure it helps, but still I woulnd't say its a permanent fix for GPS.
[Captivate General] shoman94:
In my house.... not next to a window..... I didn't time it exactly but in about 90 seconds I found 7 and am fixed to 4 with an error of 16 ft...... pretty instant outdoors.....10-15 seconds....
[Captivate General] static416:
At least initially, this has produced fantastic results for me.

Previous to this I often couldn't get a lock at all. I'd turn it on in my car, and it would sit there for 5-10 minutes and never lock on to anything.

Now not only can I get a lock, I can get a lock indoors, with 12 satellites, in seconds.

Have not tried it with navigation, so there may still be tracking issues, not sure.

But overall this is an awesome discovery.

You'd think that Samsung would notice something like this fairly quickly and correct it in manufacturing. Even if it doesn't solve everything, it seems to reliably show significant improvement. But based on the lack of a response to GPS issues, and the non-existent Froyo update, I think that Samsung basically stops all development as soon as the phone is out the door. Don't think my next phone will be a Samsung.
[Captivate General] evoic:
Dear friend.

A friendly piece of friend to friend advice.

Remove the pic showing the years of schmegma built up on that keyboard of yours.

Your friend,

Evoic
[Captivate General] jbl7979:
Hrmm, i just tried this method. FIrst thing I tried to do was use that GPS restore app that has not worked a single time since ATT/Samsung put it out. It immediately locked on and said it worked, I nearly dropped my drink i was so shocked. And im indoors, where gps never works at all. Interesting, cant wait to try it outside in the car tomorrow.
[Captivate General] avs420:
Instead of a paperclip I recommend a sewing needle as the point is much finer and you can raise with less pressure.

I scratched off the back panel silver section with a screw driver and adjusted the notch as high as I thought it would go without pressure.

I'm viewing and locking 9 satellites in an indoor apartment (2 floors) and i'm on the bottom.

I'd say this helped some!
[Captivate General] sclRanger:
It has been permanent for me so far. I am not rooted and am running stock. I did not pry the contacts up, I just cleaned off the white film with my pocket knife.
[Captivate General] K-mart Shopper:
So we have two launch Captivates.. One has always tracked perfectly, mine has not. Both have same contact areas on the white "surface." Of course, I decided to scratch mine up!

Inside.. locked onto 10 out of 10 satellites in about four seconds. That's definitely an improvement. It used to juggle between 5 satellites without getting a lock.

If I ever can remember, I'll test the navigation while driving. Although I've gotten good locks before, it's never tracked with any accuracy worth mentioning - it's not reliable enough to navigate anywhere.
[Captivate General] Canada_Will:
This seems to have helped me as well. Tried a speed test today and never got anywhere near this fast on cell

Getting consistently ten to eleven satellites inside.
[Captivate General] Hooligan63:
This has worked great for me on my completely stock and unrooted Captivate. Before I could sometimes get a lock standing in a wide open field and it would have me within about a 100 ft at best. Useless in the truck for navigation.

Now I get more sats and better locks. Have used it three times in the truck and it navigates perfectly even sitting in the cup holder.

Thank you!!!
[Captivate General] bames:
lol +1 on the smegma-board.

The second picture made me laugh as well especially when coupled with the advice in the post "Be Careful not to break it"

Step 1 in not breaking it. Don't use the biggest screw driver you own.
[Captivate General] ewingr:
Not sure if its a typical GPS inconsistency, but, for the first time in several weeks, this morning my GPS was wonky: putting me off the road etc.

What changed? I installed Google maps 5.0.

On Co-Pilot, it held the road fine.
[Captivate General] Belaflek:
strangest thing for me..outside gps was accurate to 2800m...turned on wireless..even tho I was in a park...instantly went down to 10m

go figure.
[Captivate General] joeybear23:
FYI - I saw this in the Vibrant forums:

http://xdaforums.com/showthread.php?p=9923176#post9923176

Anyone brave enough to give it a try?

My GPS does not have the issues many are having, so I don't need this...
[Captivate General] polarbee:
That's the same contact as the one on the Captivate except ours is accessible without disassembly.
[Captivate General] nkrick:
Due to design differences between the Captivate and Vibrant, it is not necessary for us Captivate owners to disassemble our phones to get to the contact. Since the Captivate uses a metal back plate, Samsung used the back plate itself for the antenna (apparently) instead of having it run inside a piece of plastic that is internal to the phone.
[Captivate General] Ben74:
i did this mod yesterday, and had great results. got a lock indoors for the first time. however, this morning, i could no longer get a lock indoors. i was seeing 2-3 sats, instead of 7-8. i re-scraped the contact points on the cover, and cleaned them with a white eraser, and now i can get a lock indoors again. seems like this mod might be short lived. the battery door is made from aluminum, and aluminum does oxidize in normal air, so maybe this only works when the contact points are freshly scraped? anyone else have a similar experience?
[Captivate General] crydee:
I tried it. No change for me. I get locks but It's over a mile and a half off on where it says I am, I imagine in a bit I'll be getting any other symptom I had before. Before I was getting no locks, widely inaccurate, or sometimes accurate yet slow.
[Captivate General] a.vandelay:
oh, thanks. i actually do get better gps after a reboot. i assumed people were turning their phones off before scratching various contacts!!
[Captivate General] jth747:
My experience with this

So I took off the cover and did the scrape and lifted the contact, booted up

while i had the cover off, got 7 sats with no lock indoors (I have a metal roof),

I had never been able to pick up even one sat indoors before. Finished and put

the back on again, 3 to 4 sats with no lock indoors now. Tried it outside and

got 6 sats with lock and 10 meter accuracy within about 45 seconds. That was

last night, so today I decided to remove the back cover, put my skin case on

and try it out. 7 to 8 sats indoors (remember metal roof), outdoors I got a lock

on 8 of 8 sats in about 30 seconds with GPS Status, 5 meter accuracy, never

saw that before, Google maps locked in about 25 to 30 seconds and held a lock

while I walked around quite a lot, never got that before either. As far as Cell

signal strength, without the back I am seeing about a 1 bar improvement (I have

marginal service here) with a slight but noticeable improvement after the cleaning

and bending, with the back on. From my experience I can say that there is

definitely something going on here, maybe there is a way to further optimize

signal. For now I think I'll run mine minus the back cover for a while and see.
[Captivate General] sixk:
wow... so easy yet so effective

thank you.

I got all 6 sats in my area in about 20 seconds and my gps was spot on.

of course i didnt have the back cover on but still. ^^
[Captivate General] waldo98:
i just tried this right now and my gps locked in within 10 seconds. i'll have to test it out more in various areas but it looks promising so far

thanks to whomever found this out
[Captivate General] oriongaby:
It doesn't really matters how big the tool is, as long as you know how to properly do it.
[Captivate General] gormander:
Just an FYI to you all. I do not believe those contact points that touch the back casing are antennae's at all. I took a continuity tester and tested the two contact points with the test probes. They are actually connected together as indicated by the continuity tester. I also tested this by touching what we all seem to believe was the GPS antennae and the metallic piece that holds the SD card (which is typically Ground). Those two points are in fact connected/shorted as well. Im not a RF engineer or anything but I don't think antennae's are shorted to ground planes.....ever.

I also touched what we all think is the GPRS antennae to the metallic piece that holds the SD card and those are also connected/shorted.

I did this with the battery out and device powered off. Not sure if this info helps anyone but it does seem like the OPs technique does drastically improve people's GPS by making a better connection to the back plate. What could be happening is that Samsung was having EMI issues and are using a big ground plane to supress those EMI emissions...which in turn, making a better contact to the back plate helps this.
[Captivate General] jth747:
I was going to do the same checks, but hadn't gotten to it yet, your post confirms my

thoughts on what it is, solid chunk of metal, lol. That might explain the boost in both

GPS and Cell signal strength when it is not present also, just removed a big blocking

shield ? Anyway, it definitely boosts signals to remove it.
[Captivate General] NascarFastcar:
Was gonna leave the back of my phone off since I have a otter box commuter. But then I noticed the big hole left for the speaker area. Didn't want all sorts of stuff going in my phone.

Any aftermarket plastic back covers for these phones?
[Captivate General] ewingr:
:eek: Uh...no comment.
[Captivate General] Caliesv:
Is everyone using the original gps settings?
[Captivate General] shoman94:
I never touched my settings. All stock.
[Captivate General] mikegy2002:
grease

Knowing and working with aluminun everyday I assumed the instant start of oxidation. I should have mentioned the use of die electric grease on the contact points.
[Captivate General] mikalcarbine257:
Thanks for someone finally pointing this out. I've been lurking this thread dying to post but my account privelages got all messed up so I had to make a new account...

There is no way any designer would make your battery backing an antenna. However I believe samsung made the device connect to the back casing to increase the size of the ground plane of the phone and antenna. This plays an equally important role. An antenna with a poor ground will be a poor antenna. This coincides with your testing above.

So by us cleaning the contacts on this casing you are improving the ground potential of the system, ie improving antenna and gps signal. I have some testing to do myself but my volt meter is broken. I'd be interested to see someone attach a massive ground plane to this and record the results (should be excellent) this may lead into tin foil ground plane mods in the future. Anyone have some alligator clips or a soldering iron?

Btw I'm an electrical engineer with RF background working in telecom
[Captivate General] reinbeau:
mikalcarbine257, you've brought up an excellent point with this:

Back in the old iQue forum we joked about setting Betty (our name for the iQue) on a pan for a hat to get better reception (for those who wanted to use it outside for hiking, not the best GPS for those purposes, but for many, it was their only GPS). My point is the use of an external antenna, or a big ground plane, greatly enhances GPS signals. I've thought all along that this is the problem for the Cappy. That and people believing you can get GPS signals through solid walls (without the use of windows).
[Captivate General] mikalcarbine257:
I'll have some free time next week to really dive into this.

On a related note, there appears to be a micro BNC or UFL (some kind of coax) connector on the rear of the captivate under the battery cover. You can see it in a small recessed circular hole. This could very well be some kind of external antenna or test port. However to verify this I feel you'd need the right equipment...
[Captivate General] MikalCarbine:
Got my old account back :-)
[Captivate General] Scott_S:
My question is, why would Samsung put a coating on the points of contact that would degrade the integrity of that point of contact?

Unless the batch of the material used was defective or something.

The results people are having in this thread speak for themselves, but...
[Captivate General] elsidd33:
I've been playing with this for the past several days, and while I've seen improvement, the GPS function is still pretty intermittent. I have noticed that I can generally get a lock (using GPS Status app) outside, and that the lock usually persists while driving. However, I have a much harder time getting a lock in Google Maps (version 5014).

I've seen a few posts about difficulty with GPS in Google Maps 5. I'm wondering if I might have better luck using something like CoPilot (don't want to buy it just to experiment, though). Any advice?
[Captivate General] shoman94:
That port looks like an external antenna connection. I've used those on motorola phones for years for in car kits.
[Captivate General] MikalCarbine:
I figured as much and starting racking my brain for a complex home made solution based off that connector, then your post made me realize I was thinking too much and I found this:

http://blog.wpsantennas.com/2007/05/samsung-blackjack-i607-external-antenna.html

Same connector, should work. Who wants to be the gineau pig? 10dB improvement is more than a 2^3 increase in signal strength.
[Captivate General] gormander:
*COUGH* Apple LOL and the idea to use the outer rim as their antennas...or is that different than a battery backing plate due to the EMI emitted during the battery drain of when all your things are on in the phone? I just figured its the same concept...using an external metal piece as an antenna. Again, Im not an RF engineer, just speculating with some educated guesses from what I remember in school.

Same here. But shouldnt it work better w/ a good connection to the back plate versus not having a back plate at all? Some people in this thread are saying that their GPS is better because the back plate is off.

What kind of results are you looking for? Like end-user driving experience results (can do but results may vary over time) or actual measureable results like RF strength or SNR (cant do)? I have a soldering iron and aligator clips but to be honest, I am kind of iffy about soldering anything to the cappy. In terms of a ground plane, all I need is to connect it to the same tabs that touch the back plate correct with alligator clips? Whats a good ground plane? The chasis of my car? :-D I can test that out later today once I get a good idea of what I should be looking for from an RF Engineer standpoint.
[Captivate General] Ben74:
dielectric grease occurred to me too. have you tried it? again, this morning, the effectiveness of this mod has drastically decreased. i'm no longer getting a fix indoors. i'll do it again, and try the dielectric grease this time.
[Captivate General] ewingr:
I have purchased CoPilot. Of course, I'm in the U.S. and for the moment, it is only around $5 here. Not that big of an investment.

Interstingly, I like Co-Pilot better than Google Nav. The interface allows for some customization of the display bar at the bottom. I like to see time left and distance.

I do find it to work much better at staying on the road than Google's Nav does.

It does take a bit of getting used to after using Google for a while. The map design is so different, and of course, there are some nice features in Google that is not in Co-Pilot. The one thing I thought was not there is in fact there: using voice to enter a search over the net. Just need to find it on the menus.