Cell phone bleedover

Reply Subscribe

Thread Tools

Search this Thread

04-22-2009, 08:25 AM

Noseeums

Gets Weekends Off

Thread Starter

Joined APC: Jun 2008

Posts: 426

Cell phone bleedover

Maybe some of you more tech savy folks can answer this for me.... I have always wondered why GSM phones (AT&T, T-Mobile) always bleed over into the aircraft intercoms, car stereos, and pretty much anything else electrical. Occasionally I'll even hear a Center controller transmitting with his phone bleeding over the radio. It's that "tick tick tick - tick tick tick" sound.

CDMA phones (Verizon/Alltel, Sprint) don't seem to have the issue at all.

What is up with this? It annoys me.

04-22-2009, 09:26 AM

rickair7777

Prime Minister/Moderator

Joined APC: Jan 2006

Position: Engines Turn Or People Swim

Posts: 39,992

If there is a difference between CDMA and GSM in this regard is due to different frequency or digital pulse patterns. Any electronic device can act as an antenna if the characteristics of the device happen to match the characteristics of the signal. GSM phones definitely seem to be able to drive interference in tuning heads or patch panels.

Analog phones or handheld VHF radios can trigger the smoke detector in CRJ200 cargo bays.

04-23-2009, 07:45 AM

Outlaw2097

A Second Past V1

Joined APC: Feb 2007

Position: Assumed

Posts: 743

ive found if the phone has sim cards, it ticks. at&t are the worst.

not sure if its trying to sync or whatever have you, but i hear it even if the phone is on airplane mode.

04-23-2009, 11:12 AM

Noseeums

Gets Weekends Off

Thread Starter

Joined APC: Jun 2008

Posts: 426

Yes, sim card phones are GSM phones (AT&T, T-Mobile). They're the only ones that do it.

04-25-2009, 07:49 AM

flyandive

Airport Hobo

Joined APC: Apr 2007

Posts: 844

Quote:

Originally Posted by Outlaw2097

ive found if the phone has sim cards, it ticks. at&t are the worst.

not sure if its trying to sync or whatever have you,

Anytime it's using it's antennae, checking signal, email, sending or receiving a phone call or text. On a GSM it probably, has to do with a higher frequency. AT&T? You're probably dreaming. Maybe it's just all those data intensive iPhones they have?

Quote:

Originally Posted by Outlaw2097

but I hear it even if the phone is on airplane mode.

Really? I'll bet it's coming from something else or Wi-Fi is still turned on.