Cell Phones on Planes?

[Bubba]

News is reporting that the FCC is considering allowing cell phone use on planes once they reach 10,000 feet. How do you feel about this?

[shortski]

A good rule of thumb if you can't smoke you also shouldn't be able to use a cell phone.

Think, theaters, restaurants, bars, airplanes, church, K gondi.

[Mister Moose]

I can think of 3 arenas of concern:

1) Annoying your seatmate. See nanny-state argument currently going on about smoking in gondola cabins.

2) Bridging multiple cell towers at once from high altitude. Used to be a problem, maybe Geoff can chime in on current state of the art.

3) Interference to aircraft navigation. I never understood this one. Aircraft nav systems work on 108-118Mhz. Voice is on 118-135Mhz. Cell phones are way up on 900Mhz to 2,000Mhz. Even harmonics in the RF section of the phone transmitter would be no factor.

[skifaster]

God no... Can you picture it now; some ignorant Longggg Island peeps on flights, carrying on about there ducking ropes antics, under the guise of it being reserved at Killington, with that heinous accent...
God help us....
Just sayin...

[Bubba]

I can think of 3 arenas of concern:

1) Annoying your seatmate. See nanny-state argument currently going on about smoking in gondola cabins. - My biggest concern. And it's not just your seatmate; it's many rows around you.

2) Bridging multiple cell towers at once from high altitude. Used to be a problem, maybe Geoff can chime in on current state of the art.

3) Interference to aircraft navigation. I never understood this one. Aircraft nav systems work on 108-118Mhz. Voice is on 118-135Mhz. Cell phones are way up on 900Mhz to 2,000Mhz. Even harmonics in the RF section of the phone transmitter would be no factor.

I don't think harmonics would be a problem seeing as the frequency difference would mean you're talking about 6th harmonic or higher and, even with that, I'd think that the cell phones would be subject to harmonics from the aircraft systems rather than the other way around. However, although I have to assume that aircraft electronic systems are properly shielded, couldn't you have some form of fundamental overload? I have no idea what the power output of a cell phone is but if someone is using a phone (or multiple phones are in use) I would think the potential exists even if to a very limited extent.

[Ben Zenees]

I don't think harmonics would be a problem seeing as the frequency difference would mean you're talking about 6th harmonic or higher and, even with that, I'd think that the cell phones would be subject to harmonics from the aircraft systems rather than the other way around. However, although I have to assume that aircraft electronic systems are properly shielded, couldn't you have some form of fundamental overload? I have no idea what the power output of a cell phone is but if someone is using a phone (or multiple phones are in use) I would think the potential exists even if to a very limited extent.

i could live with cell phones, but please, no harmonicas.

[SnoBrdr]

They should also be totally banned by any driver in a auto as well.

[skifaster]

They should also be totally banned by any driver in a auto as well.

Agreed!

[Mister Moose]

couldn't you have some form of fundamental overload?

What do you mean by 'fundemental overload'?

[Dr. NO]

I think the cell tower problem at altitude is covered by the aircraft being the tower and making the necessary connections. I have gotten a kick watching some people pull out a cell phone at 30K feet trying to pick up a ground tower. Not working very well, and then we went over the ocean. I go with how many annoying people would get on the phone and talk about anything and everything, and then raise their voice if they can't hear.

[Bubba]

couldn't you have some form of fundamental overload?

What do you mean by 'fundemental overload'?

Fundamental overload refers to a receiver picking up a source so powerful it causes overload, i.e. the receiver is picking up the fundamental output of the functioning transmitter, but is overpowered by it.

Although transmitter power levels are far different, as a ham radio operator I have at times interfered with my own TV even though the set was connected to cable and I had extra harmonic suppression on my transmitter. Signals can also be picked up by a phone in the same way. The signal was actually being picked up by internal wiring of the TV or phone even though everything else had been done to kill potential sources of interference. I've also used a portable phone very close to a TV and seen interference patterns on the screen.

The fact is, a signal doesn't have to be that strong to enter a device if the device wiring is either not properly shielded or if there is a break in the shielding somewhere, such as worn insulation. Again, I don't think this would be a problem for aircraft given their construction as well as the fact that cell phones don't emit a lot of power, but it would be something to look into in terms of risk nonetheless.

[robrules]

The last thing I would want is to be stuck next to someone for hours babbling incessantly about the minutiae of their lives - especially some teenager who doesn't have enough sense to curtail the conversation out of respect for others. Bad enough when strangers who meet each other on the plane do it, but is usually infrequent, give the ability to call someone they know to have a conversation and it won't be. And how annoying will it be to get a call from someone just because they are on a plane and bored and call you just to be entertained.

[Mister Moose]

Fundamental overload refers to a receiver picking up a source so powerful it causes overload, i.e. the receiver is picking up the fundamental output of the functioning transmitter, but is overpowered by it.

Although transmitter power levels are far different, as a ham radio operator I have at times interfered with my own TV even though the set was connected to cable and I had extra harmonic suppression on my transmitter. Signals can also be picked up by a phone in the same way. The signal was actually being picked up by internal wiring of the TV or phone even though everything else had been done to kill potential sources of interference. I've also used a portable phone very close to a TV and seen interference patterns on the screen.

The fact is, a signal doesn't have to be that strong to enter a device if the device wiring is either not properly shielded or if there is a break in the shielding somewhere, such as worn insulation. Again, I don't think this would be a problem for aircraft given their construction as well as the fact that cell phones don't emit a lot of power, but it would be something to look into in terms of risk nonetheless.

I dunno. All signals 'enter' a device that isn't shielded. What matters is whether the signal is on a frequency close enough to those that device is using to modify the source signal and skew the nav functionality. Cell phone frequencies aren't even close. Other mitigating factors are:

>The antennas for voice and most Nav are in the tail, top of the rudder. Way away from the cabin. The cables run through above the ceiling, or below the floor, and are further shielded by the layer of aluminum.

>A few are on the center belly, and most of those are in the Ghz range, like radar altimeters, transponders, DME. They are outside the aircraft faraday cage.

>Signal strength varies as the cube of the distance. Cell phones are weak. Do the math.

Anecdotally, I never saw any signal skew or go eratic for any reason other than going out of range. The most likely case of potential interference is anything that generates AM noise that would interfere with an NDB (A type of AM radio compass) This type of equipment is used mostly for giving check airmen something to make the trainee sweat a little as no one ever uses it in daily practice. (Other than to listen to the world series or point to the outer marker on approach, something ATC does for you anyway.)

Is it possible the ham interference you saw was through the AC line, and not transmitted through the antenna?

[tt431]

I remember when smoking was permitted in planes. For me, it would be just as annoying a guy talking my ear off next to me. If I wanted to watch/listen to drivel, I would watch Fox News.

[brownman]

Lots of biz professionals would likely embrace voice phone use as they 'wing' their way to the next meeting.
Much of the voice airwave use today can be handled via text. Worthless blabber can wait till landing.

Communications technology has become so overwhelming it is having a direct impact on health and sanity.
IMHO Moderation (as with nearly everything other than endless powder days ) is still the best policy.