Database Users

A2DP and TRAFFIC SIGNALS

Am I the only one who noticed this? Major interruptions, especially at crosswalks. In a city like New York, this can sometimes be a nightmare.
Any solutions?

I'm in New York City, and I found the Jabra BT620s headphones to be virtually unusable outdoors due to interference from surrounding radiowaves. As soon as I stepped inside, though, clear as a bell.
A2DP is nothing but false hopes and frustration. I've gone backed to wires.

I don't get these problems in the UK, but then, we are far more stringent on radio spectrum allocation, and device manufacturers need to licence the part of the spectrum they use.
Plus it has a major peformance impact on which side of your body you pocket the device. It will struggle more going through you, rather than from a pocket nearer the headphones, or in the top pocket of a bag, rather than in the bottom.

hd2 and x-ray

Hi guys,
last week I went for holiday in London.
At the airport, when leaving, before the x-ray checkin I used the phone and all worked fine, after the x-ray I looked at the phone and it was dead...it didn't switch on using the hang-off call button and nothing..they only way was to take away the battery and reinstall it...than It restarted wihtout problem....btw I thought that was some kind of bug and didn't give it too much importance.
Than when I come back, again before the check-in I used the phone without problem with the wi-fi airport, then check-in and when I tryed to switch it on again the phone was again dead!!! So I remember what happend just the week before when I was at the airport and start to think that when the HTC HD2 is x-rayed for some strange reason it stop working and freeze...and the only way to make it running again it's to take away the battery and reinsert...
The phone of my wife (a Nokia) hadn't any problem...and to be honest I never had problem with all my previous phone....(I had an HTC P3600 before and never had problem with x-ray).
So, did you have the same problem?
Luca

I had a succesion of devices fail on me. The only common factor was that each had been through airport security within 24 hours of failing. The scanner is supposed to be safe but make of this what you will. My HD2 has been through the same airport 3 times and it is still fine.

Your not actually supposed to expose any electronic device to any sort of radiation while it's turned on. Especially Gamma, xray or EM (electromagnetic).
I'm very surprised that they are making you xray your phone these days. It's been a little over 10 years since i was in an airport and back then they asked you to prove it worked by turning it on. I guess things have changed a bit since then.
As a case in point though, if your abit handy with computers take the side off, stick your phone in there and just very gently touch one of the chips on the motherboard. You'll notice your pc will hang. This is because the EM radition emitted from the GSM antenna screws with the chips on the motherboard.
So remember for next time. Turn your phone off and pull the battery till you get out of the immediate area of the xray machine

That's odd. I've been through many airports with many different phones and none have ever suffered as a result.

M3PH said:
Your not actually supposed to expose any electronic device to any sort of radiation while it's turned on. Especially Gamma, xray or EM (electromagnetic).
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i seen a video some time ago on youtube where someone left their point n shoot camera in video record mode and put it though the xray scanner. you could visibly see "electrical noise" in the recorded video as it passed though the xray beam.
safe to assume this will happen in phone too, so any data being processed or written into ram or maybe even flash as the phone is bombarded with xrays has a potential for corruption. like you said its probably best to remove all power to any device with important info, or atleast reboot it afterwords just to make sure there isnt any corrupt data sitting in ram
actually now that i think of it dram is constantly being refreshed, so there's constant data between the chip set and ram modules. all kinds of chances for xrays to corrupt data there

So would it be best if we turn our HD2 off when passing through xray machine?

Everything gets x-rayed now, without exception. I always remove the batteries before security. Note that my airline only allows 2 spare (ie. loose) LiON batteries. I haven't been hassled by this.

enyaj said:
So would it be best if we turn our HD2 off when passing through xray machine?
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Id suggest a battery pull, even when asleep the phone is still partially on, and the RAM is always active because it would loose data if it wasn't

d0ug said:
Id suggest a battery pull, even when asleep the phone is still partially on, and the RAM is always active because it would loose data if it wasn't
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Slightly off topic but i feel sorry for those suckers that pass through those x-ray machines with the laptop they just put into standby or hibernate. Say good bye to the hard drive!

Strange. I'm a frequent flyer, my HD2 went through x-ray scanners many times, always on, and I have never experienced such problem...

M3PH said:
Slightly off topic but i feel sorry for those suckers that pass through those x-ray machines with the laptop they just put into standby or hibernate. Say good bye to the hard drive!
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I dont see how xrays would damage the magnetic media any more so being on or off. I could however see the memory dump file being corrupted if the laptop was still in the process of hibernating as it passed though the xray beam, since the xrays would get at data being processed in the HDs onboard DSP, cache or bus cable
i would think there would be a better chance of xrays damaging data stored on flash memory and SSDs than magnetic media, especially as the lithographic processes shrink to create the flash memory chips

I dont understand why do hospital keep wasting funds on please turn of your mobile posters in the hospitals when people like you dont bloody read it and then go cry on XDA. You not meant to expose any phone to radiation!! jeez
seriously

evolutionqy7 said:
I dont understand why do hospital keep wasting funds on please turn of your mobile posters in the hospitals when people like you dont bloody read it and then go cry on XDA. You not meant to expose any phone to radiation!! jeez
seriously
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Trust me the hospitals don't give a **** what their radiation producing equipment does to your phones or any other portable devices, they are worried about a 1watt maybe a little more transmitter inducing stray currents in their sensitive electronics.
Though you would think now a days they would take cellphones and other transmitting devices into account when developing medical hardware, especially when you consider how much hospitals pay for this hardware. I could see medical hardware in a hospital a decade and a half ago not being hardened against transmissions, since it was relatively uncommon back then. in my opinion it would be sheer incompetence from a hardware maker today not to take that into account and test for it when developing a piece of hardware.
There is also the added benefit that newer cell technology seems to induce less or no interference in other nearby equipment, and possibly use less transmit power. for example GSM/iDEN phones put next to audio equipment would almost always create noise from the signals. newer 3G/CDMA does not do this. I remember other technologies TDMA i think when placed near a CRT monitor would make the monitor look as if it were being degaussed

krzyzag said:
Strange. I'm a frequent flyer, my HD2 went through x-ray scanners many times, always on, and I have never experienced such problem...
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Keep praying, you might stay lucky!
d0ug said:
I dont see how xrays would damage the magnetic media any more so being on or off. I could however see the memory dump file being corrupted if the laptop was still in the process of hibernating as it passed though the xray beam, since the xrays would get at data being processed in the HDs onboard DSP, cache or bus cable
i would think there would be a better chance of xrays damaging data stored on flash memory and SSDs than magnetic media, especially as the lithographic processes shrink to create the flash memory chips
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SSD's were exactly what i was refering to but if a laptop is in hibernate mode then the RAM image is stored right at the start of the disk. If the drive has any power to it at all you run the risk of seriously damaging the electronics in it. Remember all disk drives -HDD's, SSD's etc - still have controller boards on them
d0ug said:
Trust me the hospitals don't give a **** what their radiation producing equipment does to your phones or any other portable devices, they are worried about a 1watt maybe a little more transmitter inducing stray currents in their sensitive electronics.
Though you would think now a days they would take cellphones and other transmitting devices into account when developing medical hardware, especially when you consider how much hospitals pay for this hardware. I could see medical hardware in a hospital a decade and a half ago not being hardened against transmissions, since it was relatively uncommon back then. in my opinion it would be sheer incompetence from a hardware maker today not to take that into account and test for it when developing a piece of hardware.
There is also the added benefit that newer cell technology seems to induce less or no interference in other nearby equipment, and possibly use less transmit power. for example GSM/iDEN phones put next to audio equipment would almost always create noise from the signals. newer 3G/CDMA does not do this. I remember other technologies TDMA i think when placed near a CRT monitor would make the monitor look as if it were being degaussed
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Most UK hostipals are so underfunded that they are still using that ancient kit. It's only in the last 2 years that the newer kit has been coming in and the restrictions have started to shift. If your american then there is no issue. They are so overfunded they complain that they have no idea how to spend all the money

M3PH said:
Keep praying, you might stay lucky!
Most UK hospitals are so underfunded that they are still using that ancient kit. It's only in the last 2 years that the newer kit has been coming in and the restrictions have started to shift. If your american then there is no issue. They are so overfunded they complain that they have no idea how to spend all the money
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All medical equipment used in UK hospitals must be CE marked. The CE mark on this equipment means that it must be able to perform with out being effected by radio waves.
The original ban in UK hospitals was because of the old analogue mobile phones, that used to pump out their signal at full strength. Not once did they ban the pagers that the medics used or the walkie talkies that the porters used - and they really pump out a massive signal.
My mate was modify monitoring computers at patient's beds in and Intensive Care Unit. He made quite a few mobile phone calls and noticed that it didn't effect the monitoring equipment once. And this was done on the 9th to the 11th of September 2001.

d0ug said:
Trust me the hospitals don't give a **** what their radiation producing equipment does to your phones or any other portable devices, they are worried about a 1watt maybe a little more transmitter inducing stray currents in their sensitive electronics.
Though you would think now a days they would take cellphones and other transmitting devices into account when developing medical hardware, especially when you consider how much hospitals pay for this hardware. I could see medical hardware in a hospital a decade and a half ago not being hardened against transmissions, since it was relatively uncommon back then. in my opinion it would be sheer incompetence from a hardware maker today not to take that into account and test for it when developing a piece of hardware.
There is also the added benefit that newer cell technology seems to induce less or no interference in other nearby equipment, and possibly use less transmit power. for example GSM/iDEN phones put next to audio equipment would almost always create noise from the signals. newer 3G/CDMA does not do this. I remember other technologies TDMA i think when placed near a CRT monitor would make the monitor look as if it were being degaussed
Click to expand...
Click to collapse
most digital signals are now shielded against in medical equipment.
Analog signals on the other hand (walkie talkie's)....

Ive never had any problems with x-raying the phone when i worked on an airport here in Sweden. I had to x-ray it every day before work.

Where I work, there isn't any equipment that can be harmed by phones. There are x-ray machines but nothing I own has been harmed by them. Then again, I don't go anywhere near them myself. If a a patient's phone is fried, tough. We do have signs saying that phone use is forbidden but not because they will cause damage.
No, the problem is patient's who answer their phone during treatment. You really wouldn't believe some of the situastions I been in when someone has whipped out their mobile and started talking (or tried talking; I work on the head end!) Worse still are some of the ring tones. A really loud scream coming from a pocket does nothing to steady my hand.

I work in an airport, have done for the last six years and everyday my phone goes through the xray machine.
Never thought about it before but will certainly start turning it off just in case.

Sitting here with a broken hand, had numerous xrays done, phone was in the vicinity and on standby. No problems so far (touch wood).

[Q] Reception, how to improve?

So, we have probably all noticed that even compared to other phones the xperia line (and the Play in specific) seem to suffer from lower reception capability.
Putting them side by side, my Motorola Droid (A855, OG Droid 1) gets a better signal both in DB measurement and in bars. Same thing for WiFi signal. I'm guessing there is an issue with design of the antenna array in the device that causes for lower reception/broadcast quality.
I don't wish to shell out $300 for a cell repeater or $300 + monthly for a femtocell that will eat my internet bandwidth (which is pathetically limited). With that in mind, I went and started looking over the device, its teardowns, and its schematics. I was looking for something as a diversity jack for an external antenna. Now I noticed, next to the battery connector, there is a small semi-covered coax input. It appears that if you pulled off the rest of the sticker, or even if you just pushed a coax prong into there you could potentially be an antenna. However, it is not specifically labeled as such on the system board or the chassis, and the schematics were largely electrical diagrams and not system board schematics. Is there any answer for this? On pretty much every smartphone I have ever owned, there is an auxillary or "diversity" coax jack for adding an external antenna or doing signal injection.
Does anybody have any input on this? I would love to be able to boost my phone's reception quality, even if only in the car or at home (even if it means a custom modded case for ease of connect/disconnect).

Cant help you with your specific question but i can throw a tip.
- Switch your phone to GSM only. It will strengthen the signal. The downside is you are stuck with G/E data speeds (slower than H).

dsswoosh said:
Cant help you with your specific question but i can throw a tip.
- Switch your phone to GSM only. It will strengthen the signal. The downside is you are stuck with G/E data speeds (slower than H).
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Sadly, with the US-CDMA variant and its firmware, I believe that is not an option. I'm specifically using the R800x. However, the board layouts are essentially identical.

I don't see the problem if you arnt getting any dropped calls. Wrap your phone in tin foil lmao
Sent from my XPlay using XDA App.

Deoxlar said:
I don't see the problem if you arnt getting any dropped calls. Wrap your phone in tin foil lmao
Sent from my XPlay using XDA App.
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Well that is sort of the problem. I live in an area that its hills are filled with lead and other heavy minerals. Dead zones and limited signal zones are rampant, especially while driving. I _DO_ get dropped calls, and more importantly dropped data. Heck I even get dropped data from the router in the house through only one wall just a room away.
Basically if I can find out where exactly the aux/diversity port is for antennas, then I could design and fabricate a better back cover to either allow for external antennas, or to integrate better antennas into the cover (like the Thunderbolt sort of does).
Side note: Wrapping it in Tin/Aluminum Foil would make it worse, I believe (yes I have limited sense of humour).

you can easely remove the rubber in front of the coax port (atleast it definitly looks like a coax port). Would like to see a back case with better antenna in it (also being able to harbor an extra fat battery).

svenk919 said:
you can easely remove the rubber in front of the coax port (atleast it definitly looks like a coax port). Would like to see a back case with better antenna in it (also being able to harbor an extra fat battery).
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The problem is that there are several coax ports. The one near the battery connector is the most obvious, but there are some more that are under the secondary cover or behind more stickers. Trying to find out which one is which or what they do is not easy. I have some basic electronics schematics, some teardown pics/video, and a really really sparse parts replacement guide, but not much else to go on.

Plug in an antenna and see if it improves?

svenk919 said:
Plug in an antenna and see if it improves?
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*laughs* I suppose that would be the easy/simple way to find out, wouldn't it?
I'll see if I can find a matching pigtail adapter and see if I can plug a big fat antenna into and see if the DBM improves for either Cell or WiFi. I wanted to see if anybody could confirm before I attempted to mod this thing.

Increase WiFi signal...

Bit of a shot in the dark, but wouldn't adding more metal (large surface area) between the WiFi pins and the antenna increase signal strength? Or is the antenna more than just some sort of metal?
Sent from my Nexus 7 using xda premium

Anyone??

I havent got a clue. But I AM curious if anyone knows...
Sent from my Nexus 7 using XDA Premium HD app

mattcooper said:
Bit of a shot in the dark, but wouldn't adding more metal (large surface area) between the WiFi pins and the antenna increase signal strength?
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Perhaps (most likely not), but for sure you will make things a lot worse in at least a full half-hemisphere of angles.
mattcooper said:
Or is the antenna more than just some sort of metal?
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Yes.
The gain and directivity of antennas depends critically on dimensions of all metallic structures (including the antenna itself) in the "near field" of the antenna. Even for simple omnidirectional "whip" antennas, the length of the whip determines the frequency band at which it will work the best. Randomly adding metal nearby will usually make things worse, or at a minimum change its directivity.
As an antenna is a passive structure, gain can only be achieved by improving it in one direction while simultaneously making it worse in more directions. But because the orientation of the tablet in relation to the WiFi router (or cell tower) can not be predicted in advance, a high-gain directional antenna can not be used - it is undesirable. This is exactly the reason that automobiles and boats do not use high gain antennas such as dish or Yagi antennas - they will be used in all orientations except perhaps upside-down. (But the tablet probably will be used while it's owner is lying down - an upside-down configuration.)
Don't get me wrong - all the metal in the tablet/handset does alter the antenna gain pattern, and some manufacturers do a better job than others in figuring out how to place a simple, low-gain antenna in their device (in relation to all the other components) so there are no (or few) "dead spots" in the antenna pattern, and that the "RF matching" between the radio chip and the antenna is correct.
Remember Apple's iPhone "You are holding it wrong!" PR fiasco? Immediately after that happened, Apple started hiring (more) antenna designers. They were already doing some of that sort of thing, and now they are doing even more of it.
To suggest that a hobbyist can modify things to improve their antenna design is the same thing as presuming that the handset/tablet designers are completely ignoring antenna design issues. I doubt that is the case.

[Q] Any way to boost NFC signal?

I'm using an Element Recon Carbon Fiber case and while I really like it, the carbon fiber seems to weaken nfc. I had a couple tags in my car and room that I can't seem to use anymore. Do things like these external antennas (http://www.amazon.com/ipartstore-Ant.../dp/B00DE76XNY) or similar ones work at all? Its not really a dealbreaker since I still like the case, but I was just looking around if there was a cheap fix available.

pinoysw1mmer said:
carbon fiber seems to weaken nfc.
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Carbon fiber is a lossy conductor, so it will reduce your NFC range. Thick cases are also problematical. You should consider using a thin plastic or rubber case. Or no case if NFC is important to you. Also orientation is also important, so the position that you hold the phone can help achieve a successful read.
The maximum coupling and therefore range is when the two antennas are parallel. So if you have trouble with a transponder (reader), hold your phone in direct contact with the NFC pad. Level, with the center of the battery door oriented over the pad and hold it stationary for a few seconds if necessary.
I can't think of anything plausible that you could do in software. Phones already use an efficient spiral loop antenna. About the only other thing that you can do is use an external antenna as you alluded to. This could be a solution for you provided that you are willing to not use your battery door and therefore lose your water resistance. If you have a good mechanical aptitude you could possible route the leads through the battery door to an external antenna with a water tight seal. But that would be outside the capabilities of most end users.
The easiest way to increase range is from the POS end, which isn't in your control. Each new generation of transponders are more efficient and tend to increase range. And thieves have been known to hack transponders with much higher, illegal power levels that can capture your NFC information from several meters.
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