Database Info

Captivate and Nexus S back cover similarity (maybe NFC?)

Anyone notice that the back cover of the Nexus S has two little gold contacts and some sort of grounding/antenna plane just like the Captivate?
http://cdn.slashgear.com/wp-content/uploads/2010/12/NEXUS-S-Hands-on-09-SlashGear-580x359.jpg
And
http://pocketnow.com/html/portal/news/0000011184/backopen.jpg
Perhaps it's only a ground plane or something, but there is a striking resemblance. We already know our Captivates have a little something special (in the back cover mechanism and inclusion of an Audience voice processing chip) that none of the other Galaxy S variants carry. Just speculation, but maybe there's a NFC radio hiding somewhere in our devices and that "ground plane" is actually the antenna. Perhaps if someone can discover what exactly the NFC antenna looks like (if it's internal, or integrated into the back cover of the Nexus S) we could make a better guess.
Unless someone else has a more reasonable explanation?

well thats an interseting theory. kind of a stretch though, any number of things it can be. i mean because the nexus has two contact points and has nfc doesnt mean that the points are related to nfc. i think that the cappy not having nfc is evidence that the backplate is not used for nfc. but we may have un used hardware, if i knew more about antennas and nfc and things i guess i could draw a better conclusion.
i can tell you that the round point on the cappy goes to ground through a plating on the back of the plastic over. i made no attempt to trace the contact that is on the board. if someone with knowledge in the area of antennas could coment that would be great but it's probably nothing.

I've noticed this too.
If you tilt the back door at the right angle to the light, you can see a vague pattern (at least on mine) which looks like an RFID antenna in the recessed square on the back. Maybe it's something? RF is not my specialty, but it looks awfully like the pic on the left http://www.new-rfid-concept.com/rfid_and_nfc.html.

Merlin_reloaded said:
I've noticed this too.
If you tilt the back door at the right angle to the light, you can see a vague pattern (at least on mine) which looks like an RFID antenna in the recessed square on the back. Maybe it's something? RF is not my specialty, but it looks awfully like the pic on the left http://www.new-rfid-concept.com/rfid_and_nfc.html.
Click to expand...
Click to collapse
Noticed the pattern too. S'why I'm curious what it's for.

Huh, but why would they put an rfid chip in a phone when android is supposed to start using nfc? My guess as to the contact points are wifi antenna contacts. I noticed I get amazing wifi pickup from routers far away. Much better than any other device I've used. Although, no signals loose reception quality when the back plate is off, wifi, cell, gps. Idk. Haven't tried bt though.
From a phone

boborone said:
Huh, but why would they put an rfid chip in a phone when android is supposed to start using nfc? My guess as to the contact points are wifi antenna contacts. I noticed I get amazing wifi pickup from routers far away. Much better than any other device I've used. Although, no signals loose reception quality when the back plate is off, wifi, cell, gps. Idk. Haven't tried bt though.
From a phone
Click to expand...
Click to collapse
Doubt it's an actual RFID in the back cover. It's just that little patch on the back cover looks very much looks like an antenna.

Really, I don't think it can be something. A mp3 player I owned for 4 years have something like this too. It's most likely to be something like digital ground just to keep the voltage stable...

Shammyh is correct, it is for NFC.

loebotomy said:
Shammyh is correct, it is for NFC.
Click to expand...
Click to collapse
What are you saying? The captivate secretly has NFC? Seems a bit far fetched since found this yet. Would be cool though.
Sent from my GT-I9000 using XDA Premium App

i know this thread is old, but i was searching for the same thing today. after i read this thread here, i found this, explaining some roms that support the chip:
"... Audience Chip support (Captivates have a special chip added that increases call quality... if it is used)." loraqu
@ http://forums.androidcentral.com/t-captivate/111137-cyanogenmod-7-vs-serendipity-vii.html
so i guess its like those weird sticker things they used to sell on tv that claimed "its like adding a 5 foot antenna to your phone!" and im assuming everyone knows by now it cant be nfc because the backplate is metal. i found it interesting, so there it is if anyones still searching.

Solving Sensation's Death Grip Issue

Ok after the previous journey with hd2's thermal problems and since i got a new htc sensation, i found myself a little bored until either devs or htc gives us some s-off for our phones. So i've heard of this death grip issue and want to give it a try to find a hardware fix for it. Some of you may know me for the geeky technical approaches, so i'll try to get some stuff working here.
Anyway, i have the Sensation from about 4-5 days. I'm yet to determine the seriousness of this issue and how much wireless transmissions are affected.
After inspecting the device construction, it's simple to assume that the reason for the death grip is an interference between the antenna emissions and the EM interference from the human body (hand).
I'll be conducting a series of measurements using some hardware tools to find out the exact cause. Only after this i can begin to work for a fix.
So far this future fix must comply with these conditions:
1. NOT to void the warranty. The fix have to be removable and the phone brought to it's original condition.
2. More easier and safe then my hd2 reheating thread . The solution must be clear, simple and must make use of generic household materials.
3. The death grip issue must be solved in a satisfactory way so that the fix itself is worth the trouble.
This is the start of a new project, it may take a while for some real results to come and the first thing to be determined is if the issue is really user solvable.
So, wish me luck.. i guess i'll be starting tomorrow and post some pictures/things i find during the process.

Good luck, I'm also tempted to start some experiments. BTW it might be worth having a extra Back cover to due testing with. You can get one from HTC.

well, that's the idea. the method must be non invasive for that back cover and must also present no risk in damaging it.

I was so annoyed by the touchscreen issue I never got round to this one :\
I wanted to test if the problem could be "reduced" by simply adding a strip of aluminium foil along the cover... You can probably come up with something better
Thank you for helping!

Thanks! If you can even slightly improve things, you'd be a god. I love this phone, but the WiFi dying (in landscape) is the one issue that constantly nags. [:
Sent from my HTC Sensation 4G using XDA App

Xlythe said:
Thanks! If you can even slightly improve things, you'd be a god. I love this phone, but the WiFi dying (in landscape) is the one issue that constantly nags. [:
Click to expand...
Click to collapse
That's funny, mine doesn't die on any orientation about the wifi.

2003evo8 said:
That's funny, mine doesn't die on any orientation about the wifi.
Click to expand...
Click to collapse
I've yet to experience this also...
Sent from my Htcclay's SuperCM7 G2 using XDA App

Ditto...I haven't experienced this either. *knocks on wood*

2003evo8 said:
That's funny, mine doesn't die on any orientation about the wifi.
Click to expand...
Click to collapse
Well it really depends on where your router is and how strong is the signal... I've tested mine with wall between it dropped significantly and even disconnects, while next to it only a bar or more but return to normal state after a few moments. But it shouldn't do that, and I've got asus wl520-gc router.

MerLinh said:
Well it really depends on where your router is and how strong is the signal... I've tested mine with wall between it dropped significantly and even disconnects, while next to it only a bar or more but return to normal state after a few moments. But it shouldn't do that, and I've got asus wl520-gc router.
Click to expand...
Click to collapse
That's true but he was saying he looses it in landscape mode.

FOTA reduced the death grip issues for me..

i will be making some physical measurements on how the phone's transceiver produces and handles 2.43 Ghz ISM type signals. At this moment i haven't tested my device for the death grip but like i've said, i have some spare time and want to help on this.
By using an oscilloscope i will try see what's happening to the signal level in real time.

2003evo8 said:
That's true but he was saying he looses it in landscape mode.
Click to expand...
Click to collapse
It's my hand touching the top of the phone when I hold it in landscape. Sorry if there was confusion. Light touches cause dramatic losses in signal on my phone.
Edit: WiFi only.
Sent from my HTC Sensation 4G using XDA App

Looking forward to results. Godspeed.

I hate to sound like an Apple fanboy but I was not able to replicate this "accidentally."
Now it might have to do with the different frequencies of the Bell verison of phone, or my signal strength.
I watched a video of someone placing the phone flat on their hand and the signal strength completely dropping off. While I was able to drop a bar of cellular signal, it was far from the video.
I did not get any noticeable drop in wifi.

I went to 3 different tmobile stores and had 3 replacement phones. They all had death grip.
also don't think its EM. I lose wifi signal by covering with single sheet of paper.

joon82 said:
I lose wifi signal by covering with single sheet of paper.
Click to expand...
Click to collapse
Cover what with a single sheet of paper, the back of the phone? You lost the wifi signal completely? I get no effect by putting a piece of paper on my phone. Never heard of lead paper.

any updates ?
is it possible to solve it with hard cover... i read smowhere that with a silicone one won't solve it.

Xlythe said:
It's my hand touching the top of the phone when I hold it in landscape. Sorry if there was confusion. Light touches cause dramatic losses in signal on my phone.
Edit: WiFi only.
Sent from my HTC Sensation 4G using XDA App
Click to expand...
Click to collapse
i have the same problem

[Q] Where is the GPS Antenna ? (Interesting case issues!)

I was rather disappointed in the GPS performance of my shiny new Desire S...
It was so erratic, I loaded GPS Test app to check out the signal-to-noise ratio.
Then, just out of curiosity I took the aftermarket outer case that I had bought (rubber+plastic) off.
The GPS signal increased dramatically and many more satellites appeared. This effect IS consistent.
I was thinking of modifying the case by cutting a hole in it to improve GPS reception, but I'm not sure where the GPS antenna is located.
I know that phone and WiFi antennas are in the battery cover, but I would suspect that the GPS antenna probably is not.
Anyone know where it is positioned ?
Thanks,
- Steve

Not sure about the Desire S, but I had Legend before and the GPS antenna was behind the camera cover. It was connected to the plastic cover in a similar way the WiFi/phone antenna connects to the battery cover using small metallic terminals. I used elimination to determine which was the GPS.
Interestingly enough, I do not suffer from poor or erratic GPS performance on the Desire S. I get quick fixes from plenty of satellites even in less than ideal conditions, eg, a moving subway train.
Slightly off topic, what I did notice though (using GPS Test) that even with 12 strong satellites, the highest accuracy ever achievable on the Desire S is 9 feet, whereas every other HTC phone I've tried (Legend, and even the very budget Tattoo) goes down to 6 feet accuracy. Wonder why that is?

Oh, maybe it is build into the cover, then. I'm used to seeing ceramic block GPS antennas which never look thin enough to be built into a battery cover.
At least my GPS works quite well too until I add the flexible case on.
I was annoyed that the case attenuates the signal, because it was a particularly expensive and otherwise beautifully made one.
If nobody knows where the antenna is, I might have to do some experiments too.
As for the ultimate accuracy of 9 or 6 feet.. Well I suspect that it's just a subtle difference in the firmware. I don't believe that kind of accuracy is reliably achieveable anyway unless you use Differential GPS techniques - And I presume Qualcomm doesn't add that kind of luxury to their phone chipsets.
- Steve

An update :
I got a GPS lock, and observed satellite signals using GPS Test.
Then I put the DS into airplane mode so no radios were active to mess things up.
Covering the lower part of the case all over (including battery cover and screen) with foil has NO EFFECT.
Covering the upper part of the case around the speaker causes GPS signals to fade away.
The hard plastic cover supplied with my case kit has NO EFFECT.
As soon as I apply the rubber part of the case kit to the upper part of the DS, the GPS signal fades.
Conclusion:
The GPS antenna must be in the upper part of the case
It's the rubber part of my case kit that reduces the GPS signal.
Hope this is if interest!
- Steve

So the GPS suffers from the death touch as well like the wifi since the antenna is at the same place.

amonrei said:
So the GPS suffers from the death touch as well like the wifi since the antenna is at the same place.
Click to expand...
Click to collapse
erm.. I thought that the WiFi antenna was in the battery hatch with all the others ?
I reckon that the GPS antenna is probably the other end of the phone up near the camera lens. I've never had a problem with it being obstructed by hand, only by my damn expensive case!

Wifi antenna is at the top too but i thought people already knew this from the famous wifi death touch/grip?

I have only 4 statelite sinal so poor, i cant do anything by this. I only hate my DS because it
Sent from my HTC Desire S using XDA Premium App

hi all
same issues with GPS here (Portugal).
but also tryed removing the (expensive) hard cover I bought and it started working ok
it catches a lot of satelites and gets a lock real quick...
so try removing the cases!!
edit: getting 10 sat / 10 used in fix - acc-5.0 from GPS... in my attic window...

poppy8x said:
I have only 4 statelite sinal so poor, i cant do anything by this. I only hate my DS because it
Sent from my HTC Desire S using XDA Premium App
Click to expand...
Click to collapse
I'm so sorry to hear about your problem.
I have many years of experience with different types of GPS and although the DS is not the best I have ever seen, it is not too bad (without the extra case, that is!) Only dedicated GPS units like SIRFstar seem to beat it, and that is understandable.
Do you only get about 4 satellites with the DS out in the open air with no buildings around? It can not work well indoors or sometimes if there are large buildings around.
Have you tried using "GPS Test" or a similar application to clear the AGPS data then load it fresh again?
If all else fails, perhaps your DS is faulty?
- Steve

fasty said:
I'm so sorry to hear about your problem.
I have many years of experience with different types of GPS and although the DS is not the best I have ever seen, it is not too bad (without the extra case, that is!) Only dedicated GPS units like SIRFstar seem to beat it, and that is understandable.
Do you only get about 4 satellites with the DS out in the open air with no buildings around? It can not work well indoors or sometimes if there are large buildings around.
Have you tried using "GPS Test" or a similar application to clear the AGPS data then load it fresh again?
If all else fails, perhaps your DS is faulty?
- Steve
Click to expand...
Click to collapse
Thank you so much for help me
I tried everything i can do i checked outside and on my house. i used gps test, gps stattus, gps-fix. And still problem
I think my DS is faulty. so sad.
My friend have one, and it work better.

An update :
I emailed the manufacturers of my rather expensive case explaining the problem.
They seem to have a good customer service department - I got a speedy reply but they claimed that they were not aware of any issues with cases affecting GPS reception. They say that all their cases are made from the same materials so they would have thought that if there was a problem, it would affect other phones too.
They have promised to pass my information to their engineers - I hope they might get in touch with me!
In the meanwhile, if I can find out precisely where the GPS antenna is on the DS, I might try cutting a gap in the rubber for it. I'm sure that would help.
- Steve

Look into the picture of this post:
http://www.android-hilfe.de/htc-desire-s-forum/133629-schlechte-gps-genauigkeit-verbessern-2.html#post1884901
It must be on the right site.

old.splatterhand said:
Look into the picture of this post:
http://www.android-hilfe.de/htc-desire-s-forum/133629-schlechte-gps-genauigkeit-verbessern-2.html#post1884901
It must be on the right site.
Click to expand...
Click to collapse
Oh, Very good indeed !
I don't speak German so I could never have found that.
I shall take a sharp scalpel blade to my rubber case and report back later.
Thanks very much for the information.
- Steve

Case
I use a Case Mate Barely There Case and it doesn't affect GPS, wifi or phone as far as I can tell.
Rick Ohlendorf

I use the Case Mate Barely There Case too, but I doesaffect the GPS for me.
When the case is on, getting a location lock in Navigation is impossible.
When I take it off, I get a lock within seconds.

if you look at the back of ds, upper portion there is 2 small holes, ive always thought that its a hole for wifi and gps. one hole below the flash led, another on right side of speaker.
then on my capdase alumor case, it also has a hole for those 2 hole, so it might confirm my theory that those are antenna holes thats why capdase also made holes for them.

I use a case-mate tough case, a much thicker dual layer heavy duty case, and I get a gps lock just fine with it on.
Sent from my HTC Desire S using xda premium

I would like to extend the GPS antenna.. I just can't open the cover, how to do? I only managed to scratch it a little..

I have no case,but the signal is very bad.I turn on airplane mode and GPS,it often takes half an hour to get my location...
Best accuracy is about 5 meters.
The cover needs a stick.HTC used some glue.

Don't buy - CaseMate Barely There for DS

It took me several weeks to understand that my new and expensive CaseMate BarelyThere is killing my GPS reception.
The phone acquires less satelites and accuracy is terrible. Having the case on, means GPS is almost unusable...
I've removed it now, and will be complaining to CM's customer service...
gb

Unfortunately this is not the only brand of case that causes these problems.
I bought an expensive otterbox case and get the same problem, although strangely other people with the same case apparently get no problems.
There are other threads in the DS forum with more details of this subject.
Buyer beware!

baaaaaaaaaaaaaaaaaaaaaaaaaw.
Case is fine, I was testing my GPS earlier this evening, locked on within 15 seconds to 5m. Even then, you should do research before you buy things, as if you had done some research you would have found this issue was quite common for some people.
Also case-mate promise it will protect your phone with a slim profile, it doesn't say it won't affect GPS signal ;-).

Mates....
1. It is depending on what firmware you are! Wether you use testing ROMs or nightly builds etc...
2. It is depending where you live (or test the gps): if i move 20 meters away from my house, i rapidly get a gps signal without changing any settings or so...
3. It is depending on the case you are using: for instance, whe i am putting on my silicon case, i almost get no longer ANY wifi and gps signal...
4. It is depending which gps connection you are trying to get: Are you using A-gps or are you trying to get a fix with the inbuilt module... The desire S has no great gps inbuilt compared to other phones like iPhone e.g. and so you almost need to connect either via wifi or mobile network on the go.
5. it is depending on what ntp server you have configured. Htc has got sometimes a wrong code in their firnwares and the servers sometimes need to be set manually to get the best fix!
Cheers

Using Case Mate Tough Case, which is a chunky dual layer case. Silicone AND plastic outer shell. No problems at all with wifi or gps. A friend has the Otter box commuter. Also no problems.
Sent from my HTC Desire S using xda premium

never knew these could affect gps n wifi...thnx all...

I've also GPS related Problems with this case. Didn't use it anymore.
Sent from my HTC Desire S using XDA App

I am also using this case but there are no problems with GPS. It depends more on a kind of application you are using. For example Sygic has a very fast fix, Google Nav takes more time. GPS status app has also fast fix, GPS fix takes more time. I have tried all this apps with and without and believe me, case has got nothing to do with it... And if you have this idea in your mind that case is blocking GPS, you will find all evidence to proof it. Just look around not only on this forum but whole internet, there is nothing so unpredictable and different to measure as GPS signal.

mx5_white said:
I am also using this case but there are no problems with GPS. It depends more on a kind of application you are using. For example Sygic has a very fast fix, Google Nav takes more time. GPS status app has also fast fix, GPS fix takes more time. I have tried all this apps with and without and believe me, case has got nothing to do with it... And if you have this idea in your mind that case is blocking GPS, you will find all evidence to proof it. Just look around not only on this forum but whole internet, there is nothing so unpredictable and different to measure as GPS signal.
Click to expand...
Click to collapse
I agree that different applications may affect availability of initiation and position data which affect GPS acquisition (lock-up) time. I also agree that the GPS signals are relatively unpredictable (well, they are moving round all the time!)
However, I have proven beyond any doubt that the case I bought significantly affected GPS reception quality.
In fact, you can have the GPS test application working with (say) 12 satellites consistently visible, then as you offer up the rubber case near the GPS antenna panel you can observe the signals falling in real time and half the satellites are lost. I estimate the signal-to-noise ratio is degraded by more than 12dB. It's either due to signal attenuation by the rubber case material, or dielectric effect de-tuning the GPS antenna.
Incidentally, I am trained and qualified in the technology areas of RF communications and the evaluation of satellite link budgets. I design this kind of stuff.
The only thing I can't work out is why some people find that a particular brand of case makes their GPS almost unworkable, while others seem almost unaffected with the same brand of case. What I have noticed is that some people describe getting a map fix "by GPS" when actually they have no GPS signal whatsoever and actually the phone is getting its approximate positional information exclusively from the phone base station.
- Steve

It's weird there are so many differents feedback on this case.
I had a barely there last year with my Galaxy S and it was fine. I'll try to get one and try it.

I myself own a case and don't find much difference in the quality of wifi aswell as gps lock.
WiFi remains the same where as the gps signal fix has always random.

I was testing gps today with new casemate barelly there, no problems at all.
Fast fix, strong signal.
As a side note, only minus is that my case is a bit loose (can move my desire s slightly up/down, less than a milimeter), but fixed it with double sided tape.

Case mate tough. Got it recently and its the best case ever. I don't really use GPS but WiFi hasnt been degraded
Sent from my HTC Desire S using xda premium

Using a case mate tough no issues here
Sent from my HTC Desire S using XDA App

tanks, and i dont like case things...

I also own this case.
No problems with Wifi or GPS here.
Smudo

Thanks
From Russia with love by my HTC Desire S

using this case, not having any issues with it, gps and wifi signal good

That's not true. It's quite a good case which does enhance the grip a lot. Signal reception has not been a problem till date.
Sent from my HTC Desire S using XDA App

GPS Signal i my cars
Hi all
I have the Silicon CaseMate skin and i works fine with both GPS and WIFI
But when im in my car there is no GPS signal because of the windshield that is coted.
When i drive my wifes car wich is the same model but without the coted windshield i get full signal with no problem...

GPS constantly out of signal

At first it worked fine but after 1 month it starts losing signal. I downloaded GPS fixes but no luck, anyone has same problems? I have a lenovo k3 note but that works fine even it is even cheaper. I look into specs, seems like stylo only eqipped with AGPS since most high end devices offer both GLONASS and AGPS.

eddie24902005 said:
At first it worked fine but after 1 month it starts losing signal. I downloaded GPS fixes but no luck, anyone has same problems? I have a lenovo k3 note but that works fine even it is even cheaper. I look into specs, seems like stylo only eqipped with AGPS since most high end devices offer both GLONASS and AGPS.
Click to expand...
Click to collapse
Same here dont really know what's going on

Other than that, I love this phone,great price and overall performance. Still I gonna dump it soon as I need GPS everyday.

Same experience here. Even the digital compass just jiggles all over unable to lock GPS or direction.. Going to try a factory reset because it used to work fine before but today it's just failing to do anything at all... But seeing others with this phone with same or similar issues does not bode well even with a reset. It seems the phone can find some GLONASS locks in the attached images "triangles" but I think this may be in error in GPS Test.

Not happy to see so many people suffer from same thing but I am glad that I am not the only one. lol

It's the antenna.
I had problems like this as well. One day, I got mad enough to smack the back of the phone against my dashboard... and lo and behold, it started working again!
As it turns out, the NFC antenna is also the GPS antenna. There are a couple of pins on the phone that touch a pair of pads on the antenna, and if they don't make good contact, the GPS won't get a good signal.
I've found that removing the back and replacing it (being sure to snap it firmly in place) will usually fix the problem. I tried (not too hard) to pry up the little tab with the pads and stick some paper under it to force it firmly against the pins, but I'm thinking that the tab (and the rest of the antenna) might be glued in place.

Bobby Tables said:
I had problems like this as well. One day, I got mad enough to smack the back of the phone against my dashboard... and lo and behold, it started working again!
As it turns out, the NFC antenna is also the GPS antenna. There are a couple of pins on the phone that touch a pair of pads on the antenna, and if they don't make good contact, the GPS won't get a good signal.
I've found that removing the back and replacing it (being sure to snap it firmly in place) will usually fix the problem. I tried (not too hard) to pry up the little tab with the pads and stick some paper under it to force it firmly against the pins, but I'm thinking that the tab (and the rest of the antenna) might be glued in place.
Click to expand...
Click to collapse
seems like it is the solution! Hopefully can last........

So the factory rest worked on taming my digital compass and gps is now locking on but clearly the antenna on this phone is less then stellar because my old HTC Vivid seemed to have better gps reception (even with it metal backplate cover) as the snr ratio is worse here than my old phone. Its also much slower to lock on and more sensitive to your hand cupping the phone or how your holding it. I dont rely on gps much so at least its usable to a fault.. Everything else this phone provides is spot on.

The paper trick worked for me to just peel up the little contacts on the back piece and put a piece of paper behind it

darrick505 said:
The paper trick worked for me to just peel up the little contacts on the back piece and put a piece of paper behind it
Click to expand...
Click to collapse
Hello, Is there anyway possible you can provide a pic? Is it the two contacts on the backplate?

Dolemaine said:
Hello, Is there anyway possible you can provide a pic? Is it the two contacts on the backplate?
Click to expand...
Click to collapse
I used toilet paper

fixed by replacing back plate
I was having the same problem with my TMobile LG G. I tried putting some paper underneath the antenna contacts, no luck. I ended up buying a used back plate off eBay for $9.
Completely fixed it. In my case, I think the original antenna was just faulty. I'd have sent it in for a warranty replacement if I hadn't, um, dropped the phone within a week of getting it and shattering the screen so I'd already had to get that fixed by an aftermarket repair place.

GPS lock fix
I tried a new back, and the paper under the contact trick, they didnt work. BUT I did read that taking the back off and tightening the screws that hold it together, will get the gps lock back. I pulled the back off and I did have several loose screws. After correcting, I rebooted the phone and gps is now operating perfectly!

I took off the back and made all the screws tight. It works fine now. Hopefully this helps others.