iphone and radio interference?

Orangee,

This article contains more information on GSM/TDMA interference:
http://docs.info.apple.com/article.html?artnum=305766

This article gives general information on radio interference:
http://docs.info.apple.com/article.html?artnum=305662

Hope this helps,

Nathan C.

With GSM phones (e.g., AT&T/Cingular, T-Mobile), the cell radio is turned on and off at a frequency of about 220 times per second. Since 220 Hz is within our audible range, if the phone is near a speaker which does not have good RF shielding, you can hear this oscillation as a buzz.

The radios of CDMA phones (e.g., Sprint, Verizon) don't oscillate like that, so they don't produce the same effect.

I have noticed the same problem with Public Address Systems when I get near the microphone. In the case of the PA Systems where I have noticed this is where there are remote wireless microphones.

I also have never had this happen before with my previous phones. I have wi-fi off so that should not be the cause.

I have looked at the manual and it does indicate that it meets FCC requirements although it does not specifically call out Class A and or B which used to be the standard for testing for EMI.

Having been tested and passing the FCC test does not necessarily preclude some minor 'burp' in the manufacturing process which overrides the original testing results. It would not be the first time that something like this happened. You would be surprised at computer companies other than Apple who have had EMI problems over the years. Some of them are huge companies.

mikeab 😉

It is, as stated at the outset, a common GSM device issue, an nothing specific to the iPhone. Indeed, for many years this kind of noise has been commonly heard in the background from such things as live sporting commentaries when a GSM phone in the area of the microphone has been actively handshaking with the cell tower.

In the old days in the UK when I first had a cellphone, I used to amaze people by answering calls before the phone had started ringing, simply because I could hear the phone handshaking with the tower via my radio as the call was forwarded.

I do not disagree with your analysis but if this is the case, "chatter" such as this would make the phone unacceptable in the US military and intelligence arena. Additionally, a number of other agencies in the civilian side of the U.S. government would have some real issues.

Any device in the past would have to be specially treated (Tempested) for use in other than commercial environments although I can see a large number of commercial users having a great deal of difficulty if this phone is really chattering.

mikeab 😉

[snip]... +I can see a large number of commercial users having a great deal of difficulty if this phone is really chattering.+

Since virtually every European cell phone is GSM and does the exact same thing I would have to conclude that commerical users are fine with it.

I agree entirely with Jeff - commercial users have used GSM devices with exactly the same radio characteristics for years with no issues, and indeed, since the iPhone has passed FCC authorization procedures, it can only be assumed to be in full compliance with regulations.

I use mine in close proximity to radio transmission equipment which is sensitive to RF interference, and have no problems with it, so it's hard to see how it could present any unusual issues in commercial environments.

Military is a different matter of course, but in that regard since it was neither designed to meet military specification or for that market, it is in company with almost every other commercial cellphone.

Jeff -

I did not say it was chattering, I think that I used the word "if".

Also, I have no idea how much this GSM phone may be chattering.

I had, prior to my iPhone, a Treo 650 (a GSM phone) for over 2 years and it never caused problems with the same PA Systems. Maybe each GSM phone has it's own footprint when there is EMI involved which could account for the difference.

mikeab 😉

In response to the other answers posted here, my experience with the iPhone over the past few weeks has been that it causes very noticeably more GSM buzz than any other GSM phone I have had. My landline phone shrieks, ipod speakers on the desk, car radio etc. they all go nuts when the iPhone is around. With other GSM phones it has been far more rare, as in every week or two I'd hear a minor buzz rather than the near constant buzz the iPhone causes. This is extremely annoying, the landline phone (Cisco) and speakers (JBL) are very new and should be better shielded.

RPatton4 -

This is exactly what I have been saying. If you read the manual it states that it has been designed to meet FCC. I hope that it was also tested to meet FCC A and/or B.

Even if it was, the actual manufacturing of the iPhone needs to be exactly the same as the unit(s) that were tested. With all the "chatter" being emitted, one has to just ask the question again regarding testing vs. manufacturing processes.

Strange things have happened to large computer companies over the years with the manufacturing being different than the test units.

mikeab 😉

It just came to me...

The other day I read a post from somebody where they were on a plane and the Attendant told them that they could not use their iPhone on the aircraft.

I poo-poo'd that post when I read it but looking back now maybe the one of the airlines knows something that we do not know. I say this as a personal speculation having been reminded about the GSM "chatter" and the airline prohibition.

mikea 😉

Interference....

Funny... ever since I got the iPhone, whenever my phone either receives a call, text or vmail, any speaker that I am close to begins to Blip. Blip is the word. Repeating Blips.

It is embarrassing. I try to look as confused and concerned as everyone else in the room (on conference calls). I have never heard of this Blip nor had this Blip before. Very strange.

Love the iPhone.


Ted

I notice sound that sounds more like static on a radio periodically. It doesn't happen often. It is on rare occasions. I can't figure out what exactly triggers it at any particular time.

However that radio interference is not specific to the iPhone. I was always a Sprint user. A few years ago I switched to AT&T and had a Treo 650 and a Nokia. They were both terrible in comparison to the iPhone. I wound up returning them and going back to Sprint. If it wasn't for the iPhone I would still be with Sprint for that reason.

My previous phone was an LG flip phone using Cingular, and I had this same problem with that phone. Actually, I think it was worse with that phone. I hope they think about fixing this sometime in the future! My husband puts his iPhone into airplane mode when he's at work because of this problem with a coworker's radio, and it means I can never get a hold of him while he's at work. Very irritating!

Just an update on my original post. People at work are now getting very annoyed with the blipping sound triggered by my iPhone. I hope they don't find out it's coming from me.

As a side note, it definitely happens when I am either getting a text or getting a call... which is handy for me, actually. I know before my iPhone even rings or vibes that I am getting a message!
🙂