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.
Has anyone else noticed the drop in WiFi signal when you cup the phone in your hand? Put the phone in your left hand so your palm is on the left side with your fingers on the right. Watch the WiFi signal tank.
It's not a big deal nor do I know if it affects anything - just a funny observation.
Just confirmed this with WIFI Analyzer. I would lose about ~10 db whenever I cupped the bottom and the second I released it went back to normal. Must mean that the WIFI antenna is on the bottom of the device. Not that it matters much as 10 db is a minimal drop.
Very interesting, when not cupping the device returns to normal. This was with my case off. The second I put my case on my WIFI signal plummeted while not even touching it. I use a silicon case that just wraps around the device. After removing the case the signal shoots back up.
Weird, huh? Mine will drop from four WiFi bars down to one.
Sent from my ADR6400L using XDA Premium App
That's crazy. Works everytime without fail. Lucky for me I never hold it like that.
Sent from my ADR6400L using XDA App
I experience the same thing, but does not seem to affect performance.
-sent via 1.21 giggawatts of android.
It's not happening for me. Weird.
I know that the antennas on the TB run through the back cover. If you open the Battery/SD/SIM compartment cover, you will notice some contacts that are in different spots and corresponding contacts on the cover. These are antenna extensions. Thusly, covering the back of the phone will drop your signal pretty good. Try holding it in a gapped grip (fingertips only instead of cupping) or hold it at the bottom (near the kickstand) and it will alleviate it.
Why it attenuates so much when you have a silicon cover on boggles my mind. I have a soft interior and hard edge silicone/plastic two piece case on and maybe a small attenuation of WiFi and Cell signal. One bar max, a few DB in stats. Dropping from full bars to one is crazy for just the cover.
You think cell phone manufacturers would have learned from Apple....
the desire s has this issue really bad. my nexus one does it too. i've been able to cup my phone and drop cellular AND wifi bars on pretty much every phone i've owned, nokia n95, n97, etc. some just have it worse than others so you may not notice it on certain devices. but its always existed.
if you are standing next to your router, than the signal will over power any attenuation you try to impose on the device. so in the same room you wont notice, but far away with weaker signal and you will attenuate for sure.
Breezer23 said:
You think cell phone manufacturers would have learned from Apple....
Click to expand...
Click to collapse
Apple wasnt the first and wont be the last...
moosez3 said:
Apple wasnt the first and wont be the last...
Click to expand...
Click to collapse
Though they did make one of the biggest errors.
That's true but Apple made Antennuation a household term.... Kinda lol.
Apple had a problem with signal? AT&T, aka A Fee & Fee, had users too dumb to know they were using too much data? It was an iBlame issue. My daily rant quota.
Seriously, though, with internal antennas, this can be an issue. I have not verified if my signal attenuated or not, nor has it affected call quality or data transmission that I am aware of.
Sent from my ADR6400L using XDA App
ryocoon said:
Why it attenuates so much when you have a silicon cover on boggles my mind.
Click to expand...
Click to collapse
Silicone cover made in china and full of lead????
kendive said:
Silicone cover made in china and full of lead????
Click to expand...
Click to collapse
lol. But do not make too much fun of them, they may cash in our country's debt..real trouble then.
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.
The signal on this phone is way worse than my old Motorola Milestone. The only time I see green for cell signal in "battery use" is when I'm outside, whereas on the Droid it was almost always solid green. I'm never out of signal but I understand that the better the signal, the less battery use by the radio.
I found a thread in the Incredible S section and a video on youtube that tried to make the antenna in the cover better by sticking aluminum foil onto the back, extending from the pins on the cover.
To test, I first tried taking off the cover (lost signal) and putting 2 thin strips of aluminum directly on the contact pins on the phone to see if I could get signal without the cover. It worked.
I then built 2 random network of strips extending the pins on the cover (without touching the other pin's extension network) and sticking them down with tape. I made contact between the aluminum foil and the pins, and with itself always non-shiney to non-shiney side. I think the shiny side might be coated with something that isn't conductive.
Now the cover is back on but I'm not sure it's making any difference. Still -87db to -97db while holding the phone in the house.
Has anyone else tried this? I might try thin copper wire next.
Any wisdom on how the stock back cover works as an antenna? Isn't it plastic? Is it just the small gold pins?
Let's build a better antenna
Sent from my Sensation using XDA App
I'm not very good but I agree with you the signal are very week
In my house I get 1 bar of signal whereas if just step one foot out of my house the signal bar goes full
Sent from my HTC Sensation using xda premium
You can make one new antenna, but you must remove old one, or else, your new one can not work as you expected. I think original one should not worse than some standard, so flash a new radio package should have some improve one this problem. I have GPS signal weak problem some months ago, but after I flash latest radio package, GPS can be locked within several minutes without a valid data connection. Before that time, my GPS can not be locked within ten minutes.
Take a look over at the HTC Titan forums, there were a few guys over there looking into signal problems and they had all sorts of ideas while I had a Titan. The titan is pretty much a sensation xl with wp7 and the titan, xl and our sensations antennae all work in the same way with the contacts on the phone and battery cover. Hope this helps.
Sent from my HTC Sensation XE using xda premium
sparx180 said:
Take a look over at the HTC Titan forums, there were a few guys over there looking into signal problems and they had all sorts of ideas while I had a Titan. The titan is pretty much a sensation xl with wp7 and the titan, xl and our sensations antennae all work in the same way with the contacts on the phone and battery cover. Hope this helps.
Sent from my HTC Sensation XE using xda premium
Click to expand...
Click to collapse
Thanks, I'll try a search there. Do you remember anything working?
I'm interested to know how the stock antenna/battery cover works first. That'll help me understand how we could improve it.
Sent from my Sensation using XDA
Flyview said:
Thanks, I'll try a search there. Do you remember anything working?
I'm interested to know how the stock antenna/battery cover works first. That'll help me understand how we could improve it.
Sent from my Sensation using XDA
Click to expand...
Click to collapse
They were using copper strips on the outside of the case that worked but obviously was ugly. But last time I checked they were looking into scraping away the top layer of oxidized contacts to get a better contact with the phone. But Titan mobile signal and WiFi signal is waay worse than sensation. Mine was so bad I sold mine and got my XE so I'm sure someone over there could fill you in or you could find something worth experimenting with.
Sent from my HTC Sensation XE using xda premium
hello,
i've tried such things when i had a sensation. I gave up since the problem wasn't that bad for me and for some more effective measures to be taken the phone itself had to be modified in a way that warranty service people would not like.
Anyway, the antennas on sensation are, as you know, located in it's back cover. Those small exposed copper pins make contact to the corresponding locations on the phone. If one would crack open the sensation's back cover and rip off it's 3 layer construction, one would see that those copper pads are linked with some small copper conductor, forming the antenna system. Unlike older htc phones i've hacked, sensation uses a different antenna layout. If I were to try to improve it, i would go by the following steps/rules:
1. Any antenna on these type of devices, is actually a bridge between 2 points, as opposed to more traditional antenna design that has a ground pin (cold connection) and the so called hot wire - the antenna itself. These 2 are separated in normal designs, but since the nature of the wavelengths involved in gsm communications these 2 wires are actually bridged and form something called a ground loop.
2. here's a typical setup for a phone implying the same antenna system like sensation. (click for a larger version)
The small pads (blocks) are pairs used for each wireless functions. So let's say that green is gsm, blue is bluetooth/wlan and red is gps. In the right side, the phone side (without the cover) you can see that these section have their ground connections linked together. If you were to use a multimeter on the phone side and try to measure each point for continuity (with the ground connection - ex. metallic shield of the microusb connector) you will find the ones corresponding to ground.
If you look into the left side, the battery cover part, you will see that each pair has it's pins linked together. At first, if you connect the cover to the phone, it would appear that you actually short circuit everything there and it looks like a huge mess. That's true, but the manner in witch the short circuit is made, creates a ground loop. These are sensible to RF signals and although hated in other areas (hum noise on some audio equipments, etc) they are essential here as they are actually what the phone uses as an antenna.
3. note that since i currently don't have a sensation, the simple graphic representation placed above may not be 100% accurate to what you will find in this particular phone. The ideea remains the same. One must use a multimeter, placed on continuity tester to measure the points on the battery cover then - the ones on the phone. You try to place your probes on those pins - the multimeter beeps, then you've found a pair. On the phone itself you'll find more pins that "beep" when measured together, once you found all of them, you'll figure out what's the phone's ground pins for these antennas.
4. Once you have a pretty good ideea on what is linked to what and how the connections are made, it's time to figure out what antenna does what function. With the back cover removed, you should try to connect each pins corresponding to a pair, you can use a small copper wire (careful not to touch anything else). If you see gsm/bluetooth/wlan/gps working, you would have found what what each pair of pins does.
5. redesigning the whole antenna system would involve placing some copper foil as material for the bridge between the pins. Small copper wire isn't good here, you need something with a greater conductive surface.
6. Experiment, you may notice some improvements but take care how you mix the parts of your custom antenna to the original battery cover. In reality, the results will be less spectacular since the whole design is, if i am to say,well ... badly engineered. The fact that these antennas are almost all the time covered by your hand when holding the phone, doesn't help either. It just proves that simpler designs (like the hd2 for example) are superior in both sensitivity and stability in this matter.
One important note, however. It is recommended that you use surgical gloves and/or use a wrist strap to reduce the amount of static electricity produces by your body and induced on those small antennas. Some of them are very sensible to these things, you may actually further reduce their performance by damaging (reducing overall gain though transistor degradation) the small and delicate input stage of their RF transceivers.
facdemol said:
hello,
i've tried such things when i had a sensation. I gave up since the problem wasn't that bad for me and for some more effective measures to be taken the phone itself had to be modified in a way that warranty service people would not like.
Anyway, the antennas on sensation are, as you know, located in it's back cover. Those small exposed copper pins make contact to the corresponding locations on the phone. If one would crack open the sensation's back cover and rip off it's 3 layer construction, one would see that those copper pads are linked with some small copper conductor, forming the antenna system. Unlike older htc phones i've hacked, sensation uses a different antenna layout. If I were to try to improve it, i would go by the following steps/rules:
1. Any antenna on these type of devices, is actually a bridge between 2 points, as opposed to more traditional antenna design that has a ground pin (cold connection) and the so called hot wire - the antenna itself. These 2 are separated in normal designs, but since the nature of the wavelengths involved in gsm communications these 2 wires are actually bridged and form something called a ground loop.
2. here's a typical setup for a phone implying the same antenna system like sensation. (click for a larger version)
The small pads (blocks) are pairs used for each wireless functions. So let's say that green is gsm, blue is bluetooth/wlan and red is gps. In the right side, the phone side (without the cover) you can see that these section have their ground connections linked together. If you were to use a multimeter on the phone side and try to measure each point for continuity (with the ground connection - ex. metallic shield of the microusb connector) you will find the ones corresponding to ground.
If you look into the left side, the battery cover part, you will see that each pair has it's pins linked together. At first, if you connect the cover to the phone, it would appear that you actually short circuit everything there and it looks like a huge mess. That's true, but the manner in witch the short circuit is made, creates a ground loop. These are sensible to RF signals and although hated in other areas (hum noise on some audio equipments, etc) they are essential here as they are actually what the phone uses as an antenna.
3. note that since i currently don't have a sensation, the simple graphic representation placed above may not be 100% accurate to what you will find in this particular phone. The ideea remains the same. One must use a multimeter, placed on continuity tester to measure the points on the battery cover then - the ones on the phone. You try to place your probes on those pins - the multimeter beeps, then you've found a pair. On the phone itself you'll find more pins that "beep" when measured together, once you found all of them, you'll figure out what's the phone's ground pins for these antennas.
4. Once you have a pretty good ideea on what is linked to what and how the connections are made, it's time to figure out what antenna does what function. With the back cover removed, you should try to connect each pins corresponding to a pair, you can use a small copper wire (careful not to touch anything else). If you see gsm/bluetooth/wlan/gps working, you would have found what what each pair of pins does.
5. redesigning the whole antenna system would involve placing some copper foil as material for the bridge between the pins. Small copper wire isn't good here, you need something with a greater conductive surface.
6. Experiment, you may notice some improvements but take care how you mix the parts of your custom antenna to the original battery cover. In reality, the results will be less spectacular since the whole design is, if i am to say,well ... badly engineered. The fact that these antennas are almost all the time covered by your hand when holding the phone, doesn't help either. It just proves that simpler designs (like the hd2 for example) are superior in both sensitivity and stability in this matter.
One important note, however. It is recommended that you use surgical gloves and/or use a wrist strap to reduce the amount of static electricity produces by your body and induced on those small antennas. Some of them are very sensible to these things, you may actually further reduce their performance by damaging (reducing overall gain though transistor degradation) the small and delicate input stage of their RF transceivers.
Click to expand...
Click to collapse
Awesome!!! Thanks bud. I'm gonna bust out the multimeter.
So the antenna is basically some copper inside the cover connecting two adjacent pins? I assume just connecting them straight isn't the best antenna (or else they would have just done that on the phone). [EDIT: Ah, for the other two antennas, they are indeed linked with a straight piece of copper. The GSM antenna is two small contacts that I assume are somehow linked through the inside of the cover] Is this connection actually long (distance) within the cover?
Also, what are those "extensive modifications" that would actually create a big difference? I bought my phone second hand so I don't think I have warranty (or do I?). Is it building a traditional ground + hot wire antenna?
Ok, here is what I found. I'm pretty sure I used the multimeter correctly. Didn't have a continuity setting per se, but there was one in the resistance category that had an arrow pointing to a plus and it worked like in example 1 here.
What I found on the cover, is pretty much what we expected.
What I found on the phone is kind of surprising: each pair is connected to itself. Each pin is connected to the ground already as well, EXCEPT for 1 near the top.
Thoughts on how the ground loop is generated and what to try bridging with copper foil next?
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the design i've draw in the previous post, took the simplest design when using a ground loop in a phone like the sensation. As you can see, in reality, things are a bit more complex. Since you have those pins already connected one to another and those pairs to the phone ground (usb metallic shield) you already have a ground loop inside the phone and you actually extend it when you place the back cover.
Without trying to be more technical about multilayer pcb design or ground planes on a pcb, let's see what can be done about the gsm antenna and it's performance.
1. a logical first step would be to identify the pins corresponding to this antenna. Try to make some sort of cable with one end that can be fitted over those pins on the phone and the other end to an external antenna (piece of metal, if needed, use a simple metallic spoon or fork). The cable has to have 2 smaller cables inside, one for each pin. Once you find where are the pins for the gsm antenna we can proceed further. You may want to try other means to identify this, it's just that you may need a cable later on this "guide" so i've suggested to have one ready.
2. it's kind of difficult to experiment with high frequency antenna designs since there are no hobby tools capable of measuring these kind of frequencies (in the 0.8 - 1.8 - 2.4 Ghz area) and neither their amptitude in a given circuit. Since the phone itself has some means to measure this, we'll .. aah, use the phone. Signal bars, dB meters, whatever you find relevant. Another thing i do when i experiment, is to .. oversize things for more visible and clearer results. Of course, if, let's say you have a broken old phone and want to see if it still works, you won't remove it's battery and plug it to a car battery - you will blow it up. That's not one of those things were you want to oversize. Helpfully, antennas are of different nature. So, when you have to decide if a particular type of antenna is helpful, make a bigger one just like it. If the bigger one works, and the smaller one doesn't - then the design works but it's a size problem. If the bigger one doesn't work, then surely the smaller one won't work either here so you shouldn't try to make one to fit in the phone.
3. So, you got your pins right and know what's the gsm ones. Let's talk about some of the most simplest designs. Since RF energy is invisible and.. without any tools, impossible to measure, i'll be making an analogy with magnets and magnetic forces because they are of a similar origin but you can observe the effect of magnetic forces applied to an object even if you don't see the actual magnetic fields.
So, here are the 2 examples we’ll be talking today.
As you can see in the picture, the first one is a simple metallic plate and the second one contains 2 plates, one smaller then the other (about ¼) separated and not touching each other. Below each design, you have a representation of what would you see if we were to look at them from their profile, with the antennas standing vertically. Let’s talk about how they work. In case of RF energy, you would have a RF field, a spatial area on witch these waves propagate. If you place a metallic object in this field, an amount of this field’s energy will be passed to the metallic object (the process is called “induction”). We can measure this since this process generates a bunch of free moving electrons inside our metallic object. The stronger the field or the larger the surface area -> we “aquire” more electrons. If the field is too strong, a lot of electrons are being induced, they kind of “rub” on each other and surrounding molecules (it’s called brownian effect) so we produce heat - a microwave oven works like this. If we still were to pump up a greater field and to induce more energy, we will produce more heat. If we still try to induce more energy, we will obtain nuclear fusion. If we find ourselves rather more insistent and still try, we will obtain energy-matter convesions (like einstein's e=mc2) and if we still try to induce more and more energy, the matter we create will collapse under it's own gravitational field, thus we'll obtain a small black hole and surely we'll get banned from XDA for this. But to scale things down a bit and still talk about some lonely electrons, based on the general definition of the electric current, our electrons constitute a small electric current induced in the metallic object by that RF field. In a phone, that electric current is what’s being filtered and amplified. All forms of RF fields work just like this, so in the phone’s case, gsm, wlan, bluetooth etc. Thus, we need to “aquire” (it’s not the most physically correct term.. I know, but I try to keep it simple) more electrons. That’s the role of any antenna. The first design works great in areas were you have a relatively good field strength (phone signal) since it offers a big contact surface with the electromagnetic waves. This however is not always enough in places where you have a weaker field since the longer the distance to the source, the more the waves dissipate over a greater surface and from the point of view of a single receiving device – loose energy. The second design is a hybrid between those satellite dishes you may see on top of some buildings and some high gain antenna designs use in wi-fi networking. Simply adding a second metallic plate to the larger one, changes things quite a bit. I’ll get back on it after another schematic, showing how these 2 designs receive those badly needed electrons.
So, you can see, the red square (we’ll call it emitter) and our antennas. In the first case, the red thing emits and the black thing (antenna, profile view) receives those red curved lines (field energy). Because of this, a bit of red “appears” inside the black thing.
The second case looks a bit more complicated and yep.. it is. Remember that some time ago, I’ve talked about comparing RF fields with magnetic fields for the sake of simplicity. Well.. it’s time to do that stuff.. Imagine the red thing as a strong magnet. You have 2 iron plates at some distance from the magnet. You also glue these to keep them secure and not attracted by the magnet. In this setup, we say that we’ve “placed the metallic things inside the magnetic field generated by the magnet” (or something like this). The metallic plates are subjected to the force of the magnetic field, we can observe this easily because we have to keep them secured in place, not to move near the magnet. It’s the equivalent of the RF field described above. BUT something extra is also happening. While being attracted to the magnet the plates also become temporarely magnetized. So, they, themselves, will attract other metallic objects. This means that they have created a magnetic field of their own. The smaller plate, closer to the magnet, produces a larger secondary field, it’s effects reaches the second larger plate and get’s added up to the magnet’s field. Thus, the larger plate, receives a greater magnetic field in this case as opposed to the first example were only one plate is being used. The larger plate will also produce a magnetic field of it’s own, it will also reach the smaller plate, it will be induced in it, then the smaller plate will “re-emit” it to the larger one … and it’s kind of complicated even here.
The fact is, and it’s important, if we get back to waves.. it can go the other way around. Some bunch of electrons moving inside a metal plate will also create a RF field. So, maybe it’s easier to understand now, it’s actually rather difficult to design antennas since they act in both ways. They receive a part of the RF field, but they also can emit at the same time, a part of the energy they just received. The second design incorporates this facts.
4. After all of this.. how do we link those phone pins to these plates? Well that’s simple. In the first case, we will solder of at least secure 2 wires to 2 opposing corners of that plate. Those will be linked to the phone’s pins (polarity doesn’t count here). In the second case, some experiments must be done. First connect the larger plate to the phone, just like in the first case. Observe if you have any improvements, try to also connect the smaller plate to one corner or the other (by another wire). See what produces best results.
5. How big is .. big? When experimenting with larger antennas, I suggest that the larger plate to be around 50cm – 80cm in diagonal.
6. Materials… My choice would be copper. Thickness is very less relevant. Since copper foil is harder to get, you may also use aluminum foil if you manage to secure wires on it. Copper can be found on electronics store as prefabricated “blank” PCB’s. They are pretty cheap also. You can easily solder a wire on them. If you get these things, go for a single plated one, not the ones that have both sides covered with copper.
7. If you find a design that works for you in the large scale, then will try to find a way to make it smaller and fit it the phone's back case. But if the larger one doesn't work, if any large antenna design doesn't improve things much, the smaller ones surely won't help either and the problem must be searched in other places (phone's firmware, hardware etc).
I'm sorry I've got nothing useful to input in this but a guy on here before was suggesting to create a fractal antenna? something that maximizes the area of the back cover. I googled it a bit and though it was a good idea but I totally have no ideas about how to do such.
You can get stickers that you stick inside your back cover that are supposed to improve the signal. I've read mixed reviews as to whether this actually works...
http://www.phoneaccessoriesuk.co.uk/htc-sensation/268-htc-sensation-signal-booster.html
fractal antennas are better in the respect that they minimize the space requirements for antenna modules inside the phone. However, that's not diy stuff
One could try to reproduce the design with various house hold items but at this scale, when talking efficiency a simple copper plate would outperform any household fractal antenna system.
In general, although there are phones with fractal antennas, they are more efficient in higher wavelengths (lower frequencies). For example,you may have seen frigate class military vessels at sea. They have some tall 6-7 meters antennas (not the radar dishes, or "tv antenna like" yagi ones) that look like a simple rod or an extended version of your car's fm radio. They use fractal designs, and what you see as the "antenna tube" is only the flexible, weather proof casing of the actual fractal antenna inside. But they operate on a different band/wavelength.
@chrisw99 those things are actually what i was talking when suggesting my second example for antenna design. The phone's antenna acts like the bigger plate in that example and these stickers do the job of the smaller plate. Actually in theory they should work but because of the fact each phone has a slightly different antenna or placement for the RF module and these stickers try to be the "one size fits all" type, in reality your mileage may vary.
While I like the idea of building a better antenna (I’m going fiddle w/ this tonight after work), this phone has had much better signal, GPS and Wi-Fi then my Nexus 1 could ever dream of having. GPS is instantaneous on|off (N1 would stay on for up to a min after app close), Wi-Fi connects immediately (N1 would show connection but lag before my icon turned green). I have been VERY happy w/ all aspects if it’s signal.
Ahhh, great info to wake up to haha.
The GSM pins, I forgot to mention, are definitely the bottom ones.
I agree, the wifi has great reception (except when touched; very top pins). Is the wifi antenna still propogating through the cover? Or is it just the little strip of contact?
Sent from my Sensation using XDA
normally wifi antenna should be linked to a small copper foil inside 2 layers of the battery cover. That cover seems to be made out of about 2-3-4 layers of plastic, glued together in some way. One thing i never understood, why the holes in the housing?.
If i remember well, when i had the sensation i was most impressed with the gps performance. That was above any other phone i used before. Wifi performance was not that good, especially when browsing in landscape and covering the antenna with one hand. I also had one hd2 and gsm performance was kind of worse in low carrier coverage areas. Things like hd2 having 1-2 lines of signal indicator, sensation - none.
The wireless performance of the sensation is kind of mixed, some people compaining some never having any problems.
What do you think about rewiring the antennas to switch the wifi and GSM? I.e., cover up the contacts and run wires to the other antenna from the now covered original contact points.
P.s. keeping the phone in 2G mode gives me substantially better signal (ex. -69db instead of -83db).
The only reason I want to improve the signal is for battery use for the radio. I haven't actually had no signal anywhere I've gone...yet. Am I correct in thinking more power is given to the radio under "low" signal conditions though?
Sent from my Sensation using XDA
yes, that is correct. Under poor signal, the phone's tranceiver will require more power to operate. The amplifier stage inside the transceiver will need to increase it's overall gain in order to compensate, that uses more power. However, in modern phones we're talking about 1-2mA (max. 3mA) variations in stand by. That's rather small, if we also take notice of the fact that even so, the phone won't draw 2-3mA extra all the time, only when updating it's status with the corresponding GSM cell in your area (that's why they call it "cellular network"). On older phones (i mean really old) yes, that used to be a problem since individual GSM antennas were further apart from each other, phones back then needed to have stronger transceivers inside, that were able to cope with the increased distance. A small fact: the miniaturization of phones today was possible not primarily because of evolution of electronic stuffs that go inside a phone, but because carriers upgraded their networks and newer phones didn't need powerful RF transceivers inside - along with with all their required circuitry. The second most important thing is the development of high performance li-ion / polymer cells and only at third place, the evolutions in cpu/mcu or other highly intergrated circuits that now equip even the most basic phones. Since the bulky old transceivers were gone, we had a lot of space inside to put new things like cameras or bluetooth/wlan transceivers.
About switching gsm with wlan, first of all you must test how big is the improvement. Don't switch it yet, instead place a larger copper aluminum plate for the gsm antenna and check out if it improves things. If you find out that a 0.5 meter plate improves signal reception by only 20%.. well i don't think it will be relevant at the small scale, when you switch the antennas.
Really? Only 2-3mA draw difference between perfect and low signal? I might be mistaken but I remember my old phone's battery draining quicker under low signal.
I'm going to try aluminum first, that's all I have. Does it matter how long the connecting wires are?
P.s. my signal goes down considerably during a call. -69 to -90db! Just tested outside in my backyard.
Sent from my Sensation using XDA
yes, only a few miliamps. I've conducted some tests at hardware level for this. For example, the HD2 (latest phone i've test using this, here's the topic: http://forum.xda-developers.com/showthread.php?t=1018833 ) has a standby consumption of about 4-5mA (ranging from 0.2 - 6 mA). Standby means screen off, all wireless off (except gsm), processor in low power state. If i remove the antenna, the phone will still have about 1 line on the network signal indicator. Power consumption will increase with 2-3 mA. But that's about it.
The measurements are being done using a professional multimeter directly linked in series with the phone's battery.
The situation will be different if you use the phone in order to make.. phone calls. With full signal, once you make a phone call the phone's transceiver must begin to emit to a nearby carrier antenna, therefore a lot more power will be used. While having the screen off, consumption will jump from 2-3 mA to about 210-240mA during a call. If you have low signal, you can add another 100mA. (that's much...).
So if you make frequent phone calls or use the 3g networks all the time (always on type of connection) you will increase your power consumption with about 40-50%. Stand by and some rare phone calls won't have a noticeable impact, but actively using 3g and making phone calls.. well, that's another story.
Yes, it's normal for signal to drop a little when on a phone call, especially on poor carrier coverage areas. In fact, the signal is constant but your phone's RF transceiver is using very much power to transmit and due to something called supply voltage collapse (voltage drop occurring when a large amount of energy is being drawn from the battery) the receiving part will lose some of it's sensitivity.
2G signal is actually more stronger then 3G from the user's point of view. 2G was developed first, there are more 2g antennas then 3G ones, they covered a greater area with better antenna density. It's far easier and cheaper to build and install a 2g antenna then the more complicated 3G, 3.5G or 4G ones. 2G frequency emission require less power from both antenna and connecting phone then that of 3G.
as an interesting fact, a dual core cpu phone will have a maximum consumption of about 550-600mA. This is only occurring at full load (all wireless on, benchmarks, full screen brightness, etc). From a simple calculation based on the fact that this measurement was done on a 4V battery (about 60-70% charge) we can deduct that a modern phone consumes a maximum of about 2.2Watts
Well, since I had no intention of using the cellular function on my watch, I decided to attempt installing a normal watch band and I think that it all turned out nicely. Noting that this watch will accept a 22mm standard watch band, I first checked to see if a standard 22mm spring pin would fit and it did so nicely as far as the length goes. The holes that the screws fit through are much larger than the standard pin normally fits it so to keep the pin in place within the band you have two choices. Either use a standard pin and glue it into the band so it cannot slide in either direction or use a band that uses the quick release pins like I did. I used one of the "Milanese" magnetic bands that a quick release pin would fit into. It was one that I had already and I like the adjustability of it and it is black in color which matches the watch well. Now as far as the open slots where the original band's antenna connectors is concerned, I covered them with some tiny pieces of self adhesive thin craft foam that I got at a local Walmart in the crafts department. Two small rectangular pieces cut to fit worked very well to seal off the openings and it look like it was made to be there. It was a little tricky to install the band but it seems to fit very well and is very secure as well. Here is a link to just one of many of these bands offered on eBay. I would attach a picture of my LGWU2 with this band on and worn on my arm but I do not see a way to do that here.
** UPDATE... Well I just discovered that the antennas in the original band are not for the cellular service only. I was losing my Bluetooth connection only a few feet away from my mobile phone. WiFi seemed to work pretty much the same though. I thought this would be a good idea, but I guess not. Oh well.
graywoulf1 said:
Well, since I had no intention of using the cellular function on my watch, I decided to attempt installing a normal watch band and I think that it all turned out nicely. Noting that this watch will accept a 22mm standard watch band, I first checked to see if a standard 22mm spring pin would fit and it did so nicely as far as the length goes. The holes that the screws fit through are much larger than the standard pin normally fits it so to keep the pin in place within the band you have two choices. Either use a standard pin and glue it into the band so it cannot slide in either direction or use a band that uses the quick release pins like I did. I used one of the "Milanese" magnetic bands that a quick release pin would fit into. It was one that I had already and I like the adjustability of it and it is black in color which matches the watch well. Now as far as the open slots where the original band's antenna connectors is concerned, I covered them with some tiny pieces of self adhesive thin craft foam that I got at a local Walmart in the crafts department. Two small rectangular pieces cut to fit worked very well to seal off the openings and it look like it was made to be there. It was a little tricky to install the band but it seems to fit very well and is very secure as well. Here is a link to just one of many of these bands offered on eBay. I would attach a picture of my LGWU2 with this band on and worn on my arm but I do not see a way to do that here.
** UPDATE... Well I just discovered that the antennas in the original band are not for the cellular service only. I was losing my Bluetooth connection only a few feet away from my mobile phone. WiFi seemed to work pretty much the same though. I thought this would be a good idea, but I guess not. Oh well.
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Click to collapse
Thanks for sharing, I had been thinking along the same lines as you and it seems you are 90% there, I have a few questions (and suggestions) that only you can answer
First - as far as I am aware the watch primarily uses wifi to connect to the phone, not sure if it is WIFI Direct or some sort of sharing through a shared router were both device need to be connected - not sure on this, if it is a direct connection to the watch then BT doesn't matter much.
Lets suppose you need BT to work.
So you plugged up the holes on each side of the watch which is fine and maintains its water resistance but and this is a big BUT, did you think of stripping the Connectors and antenna out of the original band and using them to plug the into the watch, you could then extend the antenna under your new band (out of site) and attach using glue or something, that way you plug the holes in the watch as intended with original connectors and also retain some of the connectivity, only you can answer this as I don't know exactly what room you have to play with, the old bands are useless anyway so maybe you could carefully strip out the bits needed to achieve this, you may only need to do it on the side that supports BT antenna
Just throwing ideas
forgot to ask
do you have a link to the bands you bought
Geoffxx said:
Thanks for sharing, I had been thinking along the same lines as you and it seems you are 90% there, I have a few questions (and suggestions) that only you can answer
First - as far as I am aware the watch primarily uses wifi to connect to the phone, not sure if it is WIFI Direct or some sort of sharing through a shared router were both device need to be connected - not sure on this, if it is a direct connection to the watch then BT doesn't matter much. Lets suppose you need BT to work. So you plugged up the holes on each side of the watch which is fine and maintains its water resistance but and this is a big BUT, did you think of stripping the Connectors and antenna out of the original band and using them to plug the into the watch, you could then extend the antenna under your new band (out of site) and attach using glue or something, that way you plug the holes in the watch as intended with original connectors and also retain some of the connectivity, only you can answer this as I don't know exactly what room you have to play with, the old bands are useless anyway so maybe you could carefully strip out the bits needed to achieve this, you may only need to do it on the side that supports BT antenna. Just throwing ideas. forgot to ask, do you have a link to the bands you bought
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Click to collapse
Thanks for the suggestions on extending the antennas but in my case, my original band is in perfect condition so I am not willing to deconstruct it yet. Th thought of using parts from an old unusable band did cross my mind and I even put out some posts asking if anyone had a broken band that they wanted to give away or sell but I have not gotten any responses on that yet. The Bluetooth and WiFi both still worked but the range from my phone was about six feet at the most. I was nice to have a smaller and lighter band for a day but it just did not work out as far as getting notifications and weather updates while walking around the house. The link you asked about is https://www.tntkstore.com/lg-band-parts. I ordered a set of new screws for my band from them. They are in China but the delivery time was not bad at less than two weeks. They sell the most parts for this watch that I have found anywhere. The fact that LG has nor offers these bands and parts is an abomination in my opinion but I love the watch anyway.
I am very careful with my watchband and do not flex the ends any at all if I can help it. I have large wrists so I only connect to the second hole but when I am putting it on or taking it off, I try to pull it as straight and gently as I can. I plan on ordering an extra band to put back as an extra. I have gotten used to the bulkiness of the band now and I don't mind it at all anymore. I wish that there were other options for more flexible bands in different styles and colors though. I have attached a picture of what my watch looked like with a Milanese style magnetic band on it. I used small pieces of adhesive craft foam sheet to cover and seal the antenna connection ports. I hope I have helped in some way with this. Have a good day.
I can live with 6 feet lol or I might just buy a spare band, I am like you and will be careful, I think if I get 3 years out of the new watch I bought I'll be doing ok and might look for what's new at that time, TBH I would have bought the Samsung S3 Frontier if it had been AW - by far the best watch out there at the moment but we shall see when the time comes
Thanks for the link
I just upgraded from a Sony SW 2 which I had for years lol and also from an Xperia Z1 to a XZ2 Premium so new stuff all round and loving it
cheers my friend
check other thread
even though I was careful my band is failing and am in the process of fitting a 22mm stainless steel band, I only use and need BT so only one antenna will need to be retained (the BT antenna probably supports the wifi too)
check out the other thread I updated with photos