Noisy 3G phones

[TE]

When my Samsung SGH-i617 Blackjack II phone (AT&T) switches from 3G
to EVDO mode, it causes interference on nearby speakers.
What is it about the EVDO mode that makes it interfere with radios &
speakers that
the G3 mode doesn't?
Does the iPhone do this when it switches out of 3G modes too?
(My previous Samsung X426 was always causing this kind of
interference, but that
was an old dual-band phone)


I also notice that my 3G phone switches from 3G to EVDO every weekday
around 6pm for
a short while, then switches back to G3.
What's going on around 6pm that causes this to happen?

[Jeffrey Kaplan]

Post by TE
When my Samsung SGH-i617 Blackjack II phone (AT&T) switches from 3G
to EVDO mode, it causes interference on nearby speakers.

Your phone switches from GSM to CDMA?

[Todd Allcock]

Post by Jeffrey Kaplan

Post by TE
When my Samsung SGH-i617 Blackjack II phone (AT&T) switches from 3G
to EVDO mode, it causes interference on nearby speakers.

Your phone switches from GSM to CDMA?

Syntax error, probably. I assume he meant switching from GSM to 3G.

All of my GSM handsets create interference that causes "chatter" on nearby
speakers (regardless of what mode they're in) when they communicate with a
tower. I can tell I'm about to receive a call when working at my desktop
PC because the speakers start chattering like crazy right before the phone
rings!

[TE]

Post by Jeffrey Kaplan

Post by TE
When my Samsung SGH-i617 Blackjack II phone (AT&T) switches from 3G
to EVDO mode, it causes interference on nearby speakers.

Your phone switches from GSM to CDMA?

Syntax error, probably.  I assume he meant switching from GSM to 3G.

Thanks.
I meant EDGE (an enhanced GSM mode?), not EVDO.
My phone switches from "3G" to "E" and back, but almost never goes all
the way down to "G" (GSM).

[Jeffrey Kaplan]

Post by TE

Post by Jeffrey Kaplan

Post by TE
When my Samsung SGH-i617 Blackjack II phone (AT&T) switches from 3G
to EVDO mode, it causes interference on nearby speakers.

Your phone switches from GSM to CDMA?

Syntax error, probably.  I assume he meant switching from GSM to 3G.

Thanks.
I meant EDGE (an enhanced GSM mode?), not EVDO.
My phone switches from "3G" to "E" and back, but almost never goes all
the way down to "G" (GSM).

It's an artifact of GSM, it's normal. Annoying, but normal. I've
heard from others that GSM 3G does not do the speaker chatter thing. No
3G where I live yet, so I have no first-hand knowledge.

"EDGE" is essentially GSM 2.5G.

[TE]

Post by TE

Post by Jeffrey Kaplan

Post by TE
When my Samsung SGH-i617 Blackjack II phone (AT&T) switches from 3G
to EVDO mode, it causes interference on nearby speakers.

Your phone switches from GSM to CDMA?

Syntax error, probably.  I assume he meant switching from GSM to 3G.

Thanks.
I meant EDGE (an enhanced GSM mode?), not EVDO.
My phone switches from "3G" to "E" and back, but almost never goes all
the way down to "G" (GSM).

It's an artifact of GSM, it's normal.  Annoying, but normal.  I've
heard from others that GSM 3G does not do the speaker chatter thing. No
3G where I live yet, so I have no first-hand knowledge.

Very embarrassing when you are in a meeting and it causes interference
with the conference phone speaker, or the speakers in the big screen
TV next to you.
Everybody looks around the room with that "OK, who's the guy with the
AT&T phone in here?" look :(
But it's good to have so many of those GSM (iPhone?) users around, so
everyone can suspect them :)

I thought keeping my phone on silent/vibrate would suffice.
I guess I'll have to turn the phone off.

How did these cell phone protocol guys get FCC clearance to deploy
these "noisy" devices?

[Jeffrey Kaplan]

Post by TE
How did these cell phone protocol guys get FCC clearance to deploy
these "noisy" devices?

You should ask that about the regulators in the EU, or various
countries in the rest of Europe, the Mid-East and/or Asia.

The US is a late adopter of GSM, it's been in wide use in most of the
rest of the world for many years before the prior AT&T Wireless started
deploying it here.

And, so far as I know, there are no regulations against a radio
transmitter from, well, transmitting.

BTW, the iPhone on an EDGE network doesn't cause such chatter in my
car's stereo speakers. My GSM Treos did. Same car, same stereo, same
speakers, same mounting spot.

[Todd Allcock]

Post by Jeffrey Kaplan
The US is a late adopter of GSM, it's been in wide use in most of the
rest of the world for many years before the prior AT&T Wireless started
deploying it here.

While we were a little late to the party, GSM was deployed here long before
AT&T Wireless started migrating from TDMA to GSM in 2000 or 2001 or so.
The test launch of Sprint PCS in Washington D.C and Baltimore was GSM back
in 1995, and Sprint ran both GSM and CDMA there for a couple of years
before selling the GSM network to one of T-Mobile's predecessors.

In the mid-to-late 90s, PacBell Wireless, the western-most member of the
unholy trinity that became Cingular, ran a GSM network in California, Nevada,

Oregon and never had to "convert" to GSM like AT&T or the rest of Cingular.

Meanwhile, the "GSM Alliance" members- rural regional PCS carriers like
Omnipoint, Aerial, Powertel, etc., most of whom became T-Mobile USA,
sprang up.

Post by Jeffrey Kaplan
BTW, the iPhone on an EDGE network doesn't cause such chatter in my
car's stereo speakers. My GSM Treos did. Same car, same stereo, same
speakers, same mounting spot.

I haven't tried my wife's iPhone over her car stereo yet. It makes the
standard chattering noises over my PC speakers like every other GSM phone
we own, though.

[DevilsPGD]

In message

Post by TE
Very embarrassing when you are in a meeting and it causes interference
with the conference phone speaker, or the speakers in the big screen
TV next to you.
Everybody looks around the room with that "OK, who's the guy with the
AT&T phone in here?" look :(
But it's good to have so many of those GSM (iPhone?) users around, so
everyone can suspect them :)
I thought keeping my phone on silent/vibrate would suffice.
I guess I'll have to turn the phone off.
How did these cell phone protocol guys get FCC clearance to deploy
these "noisy" devices?

In short, the device is doing what it is intended to do, in frequency
space allocated for this activity.

The problem isn't the mobile device, it's the speakers which are not
properly shielded from interference that are the problem.

You can run into similar issues with a larger CRT monitor, or various
other devices.

[marconey]

Exactly. Sort of.

FWIW, GSM uses TDMA technology: Time Division Multiplexing. That means it
slices the use of the assigned frequency into time slots for each user, and
then the mobile device sends its packets of data during the allotted time
slot.

What you're hearing then is the pulses of these data packets as they're
transmitted from the phone to the network. If you were to try it with a
CDMA phone, you wouldn't hear these pulses, because CDMA's Code Division
method is essentially an always-on state (no pulsing) that is instead
recognized by a specific embedded transmitted code (Walsh Code) assigned by
the network to the particular phone; and due to this always-on state,
coupled with the very low power required of the CDMA technology, (imagine a
room full of people softly speaking a thousand different languages; yet you
can clearly hear only the person speaking the language you understand),
there is no such pulsing or other external-generated RF noise of the type.

To some degree, better shielding of these mobile devices would help, seeing
as how they're mostly light-weight plastic with lots of places for RF to
leak from, including the antenna itself; but more shielding would increase
the weight significantly, and that would not be acceptable to the consumer,
so compromises have to be made. As long as the device meets certain
'minimum' regulatory specifications, it is within acceptable limits.


(( | )) marconey

Post by DevilsPGD
In message

Post by TE
Very embarrassing when you are in a meeting and it causes interference
with the conference phone speaker, or the speakers in the big screen
TV next to you.
Everybody looks around the room with that "OK, who's the guy with the
AT&T phone in here?" look :(
But it's good to have so many of those GSM (iPhone?) users around, so
everyone can suspect them :)
I thought keeping my phone on silent/vibrate would suffice.
I guess I'll have to turn the phone off.
How did these cell phone protocol guys get FCC clearance to deploy
these "noisy" devices?

In short, the device is doing what it is intended to do, in frequency
space allocated for this activity.
The problem isn't the mobile device, it's the speakers which are not
properly shielded from interference that are the problem.
You can run into similar issues with a larger CRT monitor, or various
other devices.