was watching the below linked video "hardware tour" and about halfway thru, the narrator shows a socket next to the microSDHC card, indicating it's a socket for the optional external antenna?????
the antenna socket reference is at the 2.45 mark
http://www.youtube.com/watch?v=qM0T3cBoIro&feature=related
Don't know about it being there. But there's definitely an SMA connector of some sort in the beginning of this video:
http://www.youtube.com/watch?v=gydoCVSTNFc
the way those components pop together, that poster that wanted to swap components from overseas models to add FFC and a flash might be onto something
doesnt the korean version of the galaxy s have tv, im sure i saw somewhere that it has and the antenna for the tv is on the right side if you have the phone facing away from you.
yeah, but the tv antenna is up at the top corner, like you said, upper right corner when screen faces away from you
this connector is next to the microSDHC card slot about 1.5" down
larryccf said:
yeah, but the tv antenna is up at the top corner, like you said, upper right corner when screen faces away from you
this connector is next to the microSDHC card slot about 1.5" down
Click to expand...
Click to collapse
nothing that a piece of ribbon connector cant solve, right?
started to think you were on the mark re the ribbon cable
then was watching this video again http://www.youtube.com/watch?v=lt9XNnjAcBc - at about 1:59 it shows a larger socket on the upper edge of the black subframe -
it'd be nice if the one i suspect is an optional radio antenna socket is that after all, and meant for a cradle (like sony ericsson had) that incorporated an external antenna connection
larryccf said:
started to think you were on the mark re the ribbon cable
then was watching this video again http://www.youtube.com/watch?v=lt9XNnjAcBc - at about 1:59 it shows a larger socket on the upper edge of the black subframe -
it'd be nice if the one i suspect is an optional radio antenna socket is that after all, and meant for a cradle (like sony ericsson had) that incorporated an external antenna connection
Click to expand...
Click to collapse
just watched the video and its shown clearly for about 2:10 to 2:26
It is a radio antenna socket, I have on my phone to, unfortunately I don`t have a picture to show you right now.
I believe it is an external GPS antenna Socket...
Mine has it, and probably every phone has it...
this is an GPS antenna socket ... it is MMCX socket, you can find external antenna on dealextreme : http://www.dealextreme.com/details.dx/sku.14926
The internals seem to come apart very easily - they look like they are just modules with open contact bridges that just tape in place...?
Practically every phone I've ever owned included one of these external antenna jacks (FME-Female I believe), usually hiding beneath a little rubber cover. This dates back to my first, a Nokia 6190 built in 1998 which (of course) had no GPS back then. Since the GPS (at the bottom) and cellular antennas (on the top) are separate, I can't imagine this would improve GPS signals.
It's always given me a little assurance that even in the worst dead spots, I could technically snap on an inexpensive external antenna or signal booster to get a GSM connection.
For those wondering, I've confirmed the jack is, in fact, hiding under the rubber cover on the Vibrant version of the Galaxy S. Note: the rubber cover is kinda tough to pry out, but it pops back on easy enough.
Example: Cellphone Signal Booster Pack, $30
I know people might wonder why bother, but for some of you who own Renault and Peugeot vehicles in Europe, they have heat reflecting windscreens which scuppers sat-nav use in many cases hence the reason why MMC and MMCX connectors came about.
Personally, I found it easier to have a magnetic aerial and booster in the car like this
http://www.totalpda.co.uk/Carcomm/Carcomm-GPS-Re-Radiator-Antenna.7477.html
Is there any external (portable) antenna for Galaxy S when hiking on the hillside or working at a mountain area (low signal, very2 low)....?
I found an app in /system/bin/ that lets you control your displays :-D
Now we just need to figure out the pin-out of the connector If somebody can find me a plug that fit the docking port correctly I could probably figure out the pinout for us and post instructions.
Code:
# nvdmmultidisplay
*******************************************************
dmmultidisplay usage:
dmmultidisplay [disp_option] [case_option] <activity_option>
<disp_option> can be one of the following (default is '--lcd'):
--off: Turn off all displays
--lcd: Test LCD Display
--hdmi: Test HDMI with no display on LCD
--crt: Test CRT Display with no display on LCD
--tvout: Test TV-Out Display with no display on LCD
--lcd_hdmi OR --lcd_crt OR --lcd_tvout: Test for dual display at the same time
<case_option> can be one of the following (default is '--case1'):
--case1: Demonstrate case #1
--case2: Demonstrate case #2
<activity_option> can be one of the following:
--ui: Show only UI without playing video
--play: Play only video without displaying UI
--uiplay: Show UI together with playing video
--file <filename>: Video file to be played (including path)
--query_displays: Query some info about all displays
--query_active: Query more info about active displays
Command-line examples:
Turn on LCD and HDMI displays and play default video; use case 1:
dmmultidisplay --lcd_hdmi --play
Turn on LCD and HDMI displays and play default video and show UI; use case 2:
dmmultidisplay --lcd_hdmi --case2 --uiplay
KinkyMunkey said:
I found an app in /system/bin/ that lets you control your displays :-D
Now we just need to figure out the pin-out of the connector If somebody can find me a plug that fit the docking port correctly I could probably figure out the pinout for us and post instructions.
Code:
# nvdmmultidisplay
*******************************************************
dmmultidisplay usage:
dmmultidisplay [disp_option] [case_option] <activity_option>
<disp_option> can be one of the following (default is '--lcd'):
--off: Turn off all displays
--lcd: Test LCD Display
--hdmi: Test HDMI with no display on LCD
--crt: Test CRT Display with no display on LCD
--tvout: Test TV-Out Display with no display on LCD
--lcd_hdmi OR --lcd_crt OR --lcd_tvout: Test for dual display at the same time
<case_option> can be one of the following (default is '--case1'):
--case1: Demonstrate case #1
--case2: Demonstrate case #2
<activity_option> can be one of the following:
--ui: Show only UI without playing video
--play: Play only video without displaying UI
--uiplay: Show UI together with playing video
--file <filename>: Video file to be played (including path)
--query_displays: Query some info about all displays
--query_active: Query more info about active displays
Command-line examples:
Turn on LCD and HDMI displays and play default video; use case 1:
dmmultidisplay --lcd_hdmi --play
Turn on LCD and HDMI displays and play default video and show UI; use case 2:
dmmultidisplay --lcd_hdmi --case2 --uiplay
Click to expand...
Click to collapse
Does anyone have a SandDisk Sansa device with the connector? I know you can buy breakouts of that connector (like the ipad) from Sparkfun. Maybe that one fits. It is similar to the ipad 30 pin connector
I do. The pins fit perfectly, but it's connector goes to USB. Not sure where to go from here
sledgie said:
I do. The pins fit perfectly, but it's connector goes to USB. Not sure where to go from here
Click to expand...
Click to collapse
Wow.. Ok then. I am going to order this. It is a sansa breakout plug that allows you to solder to the board. Once we get it working, we can make a cable with the plug they sell also.
http://www.kineteka.com/sansabreakout.aspx
... and see if we can figure out the pin outs!
Thanks for the update.
YOU ROCK! great find... I just ordered one too....
Does anybody know if it's safe to hook the HDMI directly into the connector? I am worried that the dock might have extra power filtering circuitry or protection we could be bypassing by hooking directly into it. (i have only heard plans for a dock, personally i would rather have an HDMI adapter, it would be AMAZING for presentations, opening up a google docs slideshows work great on this thing already)
Did you try plugging the Sansa USB cable in?
no, i just checked to see if it connected into the port. for gits and shiggles!
Yes, i did plug the USB into my computer. Nothing recognized while G Tab was running 2.04. When i reboot into CWM, i went into mounts and storage, mounted /sdcard. Computer didn't recognize. pulled USB from computer - viewsonic reset. Mounted storage in USB mode - same happened. Nothing showing up on the computer.
I know its not cost effective but wondering if something like this would do anything with the sansa usb connector attached?
http://sewelldirect.com/Sewell-HD-Deck-USB-to-HDMI.asp
KinkyMunkey said:
YOU ROCK! great find... I just ordered one too....
Does anybody know if it's safe to hook the HDMI directly into the connector? I am worried that the dock might have extra power filtering circuitry or protection we could be bypassing by hooking directly into it. (i have only heard plans for a dock, personally i would rather have an HDMI adapter, it would be AMAZING for presentations, opening up a google docs slideshows work great on this thing already)
Click to expand...
Click to collapse
Mine is on its way. Tried to find a similar breakout for HDMI, but not found yet. I guess I will just cut the end off a cheap HDMI cable and wire it to the breakout. When we get it right, I will wire it to the regular plug. I bought one of those too.
Now, who is going to figure out the pinouts? I dont have a scope to read signals like these.. just a good multi meter
insight3fl said:
Mine is on its way. Tried to find a similar breakout for HDMI, but not found yet. I guess I will just cut the end off a cheap usb and wire it to the breakout. When we get it right, I will wire it to the regular plug. I bought one of those too.
Now, who is going to figure out the pinouts? I dont have an scope to read signals like these.. just a good muti meter
Click to expand...
Click to collapse
Hello guys, I am Mike from Kineteka. We noticed traffic coming from XDA and decided to investigate. We are very interested in your discovery and would like to work with you on developing an HDMI adapter.
Regards,
Mike
Kineteka Systems
Kineteka said:
Hello guys, I am Mike from Kineteka. We noticed traffic coming from XDA and decided to investigate. We are very interested in your discovery and would like to work with you on developing an HDMI adapter.
Regards,
Mike
Kineteka Systems
Click to expand...
Click to collapse
Hey Mike! Welcome. We need help! no one has an hdmi cable for the viewsonic yet. As you see, someone believes the sansa cable fits our viewsonic dock... I and others have ordered on that chance. But we do not have the pinout on the dock connector...and as I mentioned, we need a pigtail HDMI cable to connect to the sansa breakout. Can you send me a private message and we can work on this.
thanks
Dennis
Ok... got my sansa connector breakout board/connector and a spare connetor. but, I have not a clue what to do next! The breakout board connector comes with the other parts to put around it such as the locking pins and plastic cover, but there is no way that fits over the breakout pc board, it is slotted for a cable like the parts on the regular cable connnetor I got. So I assume it does not work so I am clueless why it is included. That being said, there is very little contact with the connetor and the port on the tablet (absent the locking pins to hold it in). Now the big question is while I have it "sitting in there" (connected) how do we begin to test any signals coming out of the port??
Kinkymonkey,
Did you get your plug yet and have you had any luck with the pin out?
Mike from Kineteka, can you lend any insight on the pinout for us?
Thanks
So,, What can i supply about your development??
I have received your PM. and what information need i supply?
xjarl said:
I have received your PM. and what information need i supply?
Click to expand...
Click to collapse
We need the schematic for the connector
Thx
I just got it, but it won't fit the plug, it looks like the metal tabs under the connector are just a little bit closer together then slots on the plug - it fits in sideways but it won't go in straight because of those metal tabs :-( Did it actually fit in yours? (i have one of the first 1000....)
Ya- that black cover in the bag is wierd.. did you notice the big holes in the side too- i think those little tiny plastic clips are meant to cover them- man would that be a pain to put together. it must have come from whatever kit the sansa connector came from, They just bought a bunch of cheap connectors and soldered on the breakout board.
On a plus note, the box also contained a cool rubber ducky robot, a christmas card, and a multipage color sales guide for the archos tablet line (LOL! ironic) so it wasn't a total loss... just a really expensive rubber ducky...
oh, btw wrap a piece of electical tape around the pins coming out the back of the connector (instead of the black plastic cover), that way you don't have to worry about touching them when you are plugging in it (sending static electricity from your fingers into the HDMI connector would probably be a bad thing)
Wrap it from the thick part of the connector back down the pc board coming out the back.
I did that so i could get a better grip - but it still won't fit
KinkyMunkey said:
I just got it, but it won't fit the plug, it looks like the metal tabs under the connector are just a little bit closer together then slots on the plug - it fits in sideways but it won't go in straight because of those metal tabs :-( Did it actually fit in yours? (i have one of the first 1000....)
Ya- that black cover in the bag is wierd.. did you notice the big holes in the side too- i think those little tiny plastic clips are meant to cover them- man would that be a pain to put together. it must have come from whatever kit the sansa connector came from, They just bought a bunch of cheap connectors and soldered on the breakout board.
On a plus note, the box also contained a cool rubber ducky robot, a christmas card, and a multipage color sales guide for the archos tablet line (LOL! ironic) so it wasn't a total loss... just a really expensive rubber ducky...
Click to expand...
Click to collapse
I did not get any of those trinkets......but my plug engages but just not very deep. I wa assuming the metal hook piece ( when it would be assembled with the cover and the black plastic " buttons" for squeezing the pins) would hold it in. But the other poster said his plug fit.....so i dont know.
I wish Mike from the vendor would chime in again.
a bit confused
XDA is no longer worth my time.
I am briefly reserecting this old thread as I got my dock today. I was all set to pull it apart, cut the end off an HDMI cable and try and trace the pinout with my Sensa Breakout plugs I bought from Kinetica. Well, after seeing the connector on the dock, and knowing the Kinetica plug did not fit and I was going to have to modify and force it on someway, it is not even close to looking like the plug on the dock. I think the poster who plugged his Sansa cable in must have forced it or something or it is completely different from the cable that Kinetica sold us as a Sensa plug. It looks so much bigger in width and it the throat is much narrower ( I know the dock plug is made for the tablet to just "sit" on it and not stay pugged in, but even though it does not have the little clips on the sides that hold this type of plug engaged, the SAnsa cable is just not going to work. So, I will not be pulling the dock apart at this time until someone can spec the dock connector and find us one that is an exact fit.
I wasted $20 bucks on those two plugs unfortunately along with a few others here.
Hey everyone,
I'm not sure how many of you are aware of this product but I just found it on sale at Canadian Tire here in Canada and I'm very impressed. It's just so convenient.. I can't believe I haven't seen this before. I am amazed by it, honestly.
http://www.tetrax.com/us
Look at the XWAY and FIXWAY primarily. I purchased the XWAY at Canadian Tire for $30 (regular $50). A little expensive compared to what I am used to, but I am very happy with it so far.
The reasons I like this solution:
Works with any type of device
Sturdy and secure. Even holds me 5" GPS (though I prefer to use Google Navigation )
Allows for the keyboard to be open on most (if not all) qwerty phones
Allows for portrait and landscape rotation
Is not visible when device is on the mount
Is very small and unobtrusive when device is not on the mount
There are no clips or snaps to fiddle with, just slide off the device
You can use this with 4 devices out-of-the-box as it comes with 4 different sized magnetic pads for your devices
This does not introduce a magnetic field to yoru device (the magnet is broken into 4 and arranged intelligently)
The negative things I've discovered about this solution:
You need a magnetic pad on each device you want to use
The XWAY can be accidentally pulled off the vent if you yank the device straight off of mount instead of sliding it off
Depending on your car vents, the angle that the device is pointed might not be ideal
I will post pix tomorrow if anyone is interested! The site has quite a few to look at until then.
Here's some pix!
I don't have photos of it in the car quite yet. I'll try to get some tomorrow morning.
Today I found the FIXWAY at BestBuy and decided that I might like that better since it can be positioned in a better spot in my car. My cars vents are not ideal since the steering wheel covers part of the screen when mounted there. However, even so, the XWAY has been by far the best car mount I've ever seen or used. The FIXWAY should be even better (for my particular car).
I also discovered that the FIXWAY doesn't actually get fixed to the car itself as I thought, but instead it uses a square magnet which you fix to your car. It actually comes with 2 of these in case you want to use this in 2 cars. Like the metal button that you stick to the phone, the square metal that goes on the car has 3M adhesive on the back. It's super strong, works great.
Anyway here's some photos of both the XWAY and FIXWAY I took in my living room.
Very interesting. But, in my feeling, the lack is that we can't orientate the phone ...
I guess it depends how your car's dashboard is angled. Mine faces me just fine and the videos I've seen it seems like most work out fine
And for rotation, you can rotate it any which way before or after your phone is mounted.
I have had the xway for about 2 months now and I love it. If you are attaching it to the vents their is really no reason to have to angle the phone. I agree that if you have some weird vent configuration it may be an issue.
check this - Toyota Avensis
http://forum.xda-developers.com/showpost.php?p=9979403&postcount=74
hudy said:
check this - Toyota Avensis
http://forum.xda-developers.com/showpost.php?p=9979403&postcount=74
Click to expand...
Click to collapse
Wow I guess I didn't so the best job at reading through that thread! I even posted a link from there to here on page 11. Good pix though! Thanks
Here are some pix of the FIXWAY in the car without the phone on it (all I had to take the pix was the phone). One of these days I'll remember to bring out the camera..
Oh, and good news... It seems that you can actually angle/tilt the phone with the FIXWAY. It must be the shape of the magnet or something, and the fact that the 'X' is rubber, I am able to tilt it and it holds in place. Not a lot, but enough that I was able to cut down on some glare on the drive home
That's pretty cool, And I actually lik the blob on the back of the phone
Seconded Mac, but I would have to take my soft shell off...........................
Did your DZ battery door come stock with the wording "With Google" on it ?
Smartenup said:
Seconded Mac, but I would have to take my soft shell off...........................
Click to expand...
Click to collapse
It should stick to any shell/case just fine I would think?
For some years I use some velcro (en.wikipedia.org/wiki/Velcro). The soft side on my phone, lighter. The hard side on the dash.
Costs almost nothing. Works very well, except in the summer when it is very hot (than the glue gets sticky)
AZ2ENVY said:
Did your DZ battery door come stock with the wording "With Google" on it ?
Click to expand...
Click to collapse
mine did
Sent from my HTC Vision using XDA Premium App
FINALLY took some photos.
I am still very much in love with this thing. My whole family has'em now, which is awesome because whenever I drive any of their cars I'm set
Is it weird that it reminds me of a tie fighter?
Thanks for the recommendation and all the pictures. Difficult to find a mount that doesn't interfere with the camera and/or volume buttons.
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?
{
"lightbox_close": "Close",
"lightbox_next": "Next",
"lightbox_previous": "Previous",
"lightbox_error": "The requested content cannot be loaded. Please try again later.",
"lightbox_start_slideshow": "Start slideshow",
"lightbox_stop_slideshow": "Stop slideshow",
"lightbox_full_screen": "Full screen",
"lightbox_thumbnails": "Thumbnails",
"lightbox_download": "Download",
"lightbox_share": "Share",
"lightbox_zoom": "Zoom",
"lightbox_new_window": "New window",
"lightbox_toggle_sidebar": "Toggle sidebar"
}
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