Why can't you use FM radios on airplanes?

[White Widow]

Ok, I feel like I should know the answer to this, but I find my physics lessons a little hazy. I was flying from New York to LA a few days ago, happily listening to MP3's on my new Muvo 2000. This little (and man, it really is little) device also has a built-in FM tuner, which I decided to try out to see what I could get. I was surprised to find I could tune in all kinds of stations from way far away.

Anyway, at some point I got up to use the lavatory, and while standing in line, I asked a flight atendent if he had ever listended to the radio while flying. At that point he informed me that it was illegal to listen to FM radio in the aricraft, although it was fine to use my laptop, listen to MP3's or use my protable DVD player.

So, why is this the case? I understand why we we cannot use devices that emit EMI during takeoff and landing, but even these devices (see above) are consided OK during flight. But an FM is NEVER ALLOWED. Why?

A radio is a RECEIVER, right? I mean, the radio waves are present whether I listen to them or not. If my MP3 player is ok, why is it NOT OK to hit the FM switch on the same device and listen in? Does the tuning in somehow amplyify the FM waves or create some sort of radio frequency harmonic distorion that could impact the other frequencies used by the airplane?

So, could someone with a good working knowledge of physics exmplain this to me?

Thx,
Aaron

 

[Colt45]

FM radio has a built in 10.x MHz local osc, which will emit some RFI.. but very very minimal.

this is how nazis (et al) chased down people hiding, listening to radios.

 

[jst0ney]

No good reason besides that FM sucks. I think will will be able to use quite a bit more in upcoming years. People get scared though and the airlines do an knee jerk.

 

[91TTZ]

Doesn't sound much like a physics question.

 

[White Widow]

Well, I assumed that since somebody thought about it enough to decide it was OK to use other kinds of EM emitting appliances, that there was a good reason - well, at least *a* reason - to decide that FM radios were not ok. I can't say for sure, but I bet that a 10lbs. desktop replacement notebook puts out way more EM radiation than my tiny MP3 player/FM tuner.

So, is it safe to say that listening to FM radio does not do anything weird to alter the radio spectrum or endanger the operation of the aircraft any more than the other allowed devices? I mean, how can they ban an FM receiver, but make plans to install WiFi?

 

[DannyBoy]

Originally posted by: White Widow
Well, I assumed that since somebody thought about it enough to decide it was OK to use other kinds of EM emitting appliances, that there was a good reason - well, at least *a* reason - to decide that FM radios were not ok. I can't say for sure, but I bet that a 10lbs. desktop replacement notebook puts out way more EM radiation than my tiny MP3 player/FM tuner.

So, is it safe to say that listening to FM radio does not do anything weird to alter the radio spectrum or endanger the operation of the aircraft any more than the other allowed devices? I mean, how can they ban an FM receiver, but make plans to install WiFi?

I dunno about you, but regardless of what may seem OK in my opinion, if they say no, there's no f'cking way in hell I'm going against their word.

 

[Sukhoi]

I've done it before with no problems. I also want to know why it's illegal.

 

[Scarpozzi]

What about Cellphones? I figured as long as you're not talking on a cellphone it wouldn't matter much. I mean, it's basically a receiver when it's in standby mode...

Airlines are silly because they act like every electronic device ever made can screw up their equipment. If you ask me, the precautions are necessary when you're dealing with 100 or more passengers on one flight...otherwise, I doubt you'd be able to generate enough interference. On average, very few people carry anything that would mess their radios up.

 

[neonerd]

Originally posted by: Scarpozzi
What about Cellphones? I figured as long as you're not talking on a cellphone it wouldn't matter much. I mean, it's basically a receiver when it's in standby mode...

Airlines are silly because they act like every electronic device ever made can screw up their equipment. If you ask me, the precautions are necessary when you're dealing with 100 or more passengers on one flight...otherwise, I doubt you'd be able to generate enough interference. On average, very few people carry anything that would mess their radios up.

there was a report somewhere that said cellphones don't really screw up medical equipment, and they're running the same tests on aircrafts, because they also don't think it does anything (read that the FCC was doing this)

 

[ThePresence]

I dunno about FM, but XM is legal.
Text

 

[neonerd]

http://money.cnn.com/2004/12/09/technology/personaltech/cellphones_inflight/

EDIT: I just realised this doesn't answer your question one bit, but still good to know. Would be nice to be allowed to use cell phones on planes.

 

[V00DOO]

I think is would be a good idea for Airplanes to offer Wifi Internet service for a fee.

 

[Kyteland]

Originally posted by: neonerd
http://money.cnn.com/2004/12/09/technology/personaltech/cellphones_inflight/

EDIT: I just realised this doesn't answer your question one bit, but still good to know. Would be nice to be allowed to use cell phones on planes.

The problem with using cell phones on a plane is that it jumps from tower to tower. The phone companies can't handle that well, and it would make for a billing nightmare. Generally you stay on one tower when making a call, or maybe you jump to another tower once, but that's it. If you are jumping towers all the way from New York to LA.... Well I hope you can see the problems with that.

 

[LtPage1]

Originally posted by: ThePresence
I dunno about FM, but XM is legal.
Text

nifty. if only it were free.

 

[MrDingleDangle]

Originally posted by: neonerd
http://money.cnn.com/2004/12/09/technology/personaltech/cellphones_inflight/

EDIT: I just realised this doesn't answer your question one bit, but still good to know. Would be nice to be allowed to use cell phones on planes.

that would make plane rides horrible...imagine trying to sleep with some of these crazy people on cell phons that dont understand that u dont have to yell for other people to hear u

 

[ThePresence]

Originally posted by: LtPage1

Originally posted by: ThePresence
I dunno about FM, but XM is legal.
Text

nifty. if only it were free.

AirTran Airways' XM service provides more than 100 channels of digital-quality, commercial-free music, news, sports, talk and entertainment to passengers, who may either bring their personal headsets or purchase headsets from the airline for a nominal charge.

 

[sharkeeper]

Apparently the airlines like static. TSA certainly gives me my fair share when I travel due to the stuff that I carry despite me having all the paperwork. The airlines themselves are a PIA too.

Worry the bottle mamma, it?s grapefruit wine
Kick off your high heel sneakers, it?s party time
The girls don?t seem to care what?s on
As long as it plays till dawn
Nothin? but blues and elvis
And somebody else?s favorite song

Give her some funked up music, she treats you nice
Feed her some hungry reggae, she?ll love you twice
The girls don?t seem to care tonight
As long as the mood is right

Fm - no static at all

Give her some funked up music she treats you nice
Feed her some hungry reggae she?ll love you twice
The girls don?t seem to care tonight
As long as the mood is right

Fm - no static at all

 

[Phokus]

Because you'll be branded a terrorist, that's why.

 

[dmcowen674]

Originally posted by: Kyteland

Originally posted by: neonerd
http://money.cnn.com/2004/12/09/technology/personaltech/cellphones_inflight/

EDIT: I just realised this doesn't answer your question one bit, but still good to know. Would be nice to be allowed to use cell phones on planes.

The problem with using cell phones on a plane is that it jumps from tower to tower. The phone companies can't handle that well, and it would make for a billing nightmare. Generally you stay on one tower when making a call, or maybe you jump to another tower once, but that's it. If you are jumping towers all the way from New York to LA.... Well I hope you can see the problems with that.

Tower to tower is in the design of the system, it's called handover.

The problem with cell coverage in a plane is that the Cell tower antennas send the signal out in a straight horizontal line, in fact most have a small towards the ground downward tilt.

You are lucky if you get signal up to about 10,000 feet and yes, it would be jumping from tower to tower pretty fast (every 8-25 miles).

It is absolute BS that an FM receiver or cell phone would interfere with today's cockpit electronics.

Would you really get on a plane knowing that the electronics could get knocked out so easily???

 

[TechnoPro]

Originally posted by: dmcowen674

Originally posted by: Kyteland

Originally posted by: neonerd
http://money.cnn.com/2004/12/09/technology/personaltech/cellphones_inflight/

EDIT: I just realised this doesn't answer your question one bit, but still good to know. Would be nice to be allowed to use cell phones on planes.

The problem with using cell phones on a plane is that it jumps from tower to tower. The phone companies can't handle that well, and it would make for a billing nightmare. Generally you stay on one tower when making a call, or maybe you jump to another tower once, but that's it. If you are jumping towers all the way from New York to LA.... Well I hope you can see the problems with that.

Tower to tower is in the design of the system, it's called handover.

The problem with cell coverage in a plane is that the Cell tower antennas send the signal out in a straight horizontal line, in fact most have a small towards the ground downward tilt.

You are lucky if you get signal up to about 10,000 feet and yes, it would be jumping from tower to tower pretty fast (every 8-25 miles).

It is absolute BS that an FM receiver or cell phone would interfere with today's cockpit electronics.

Would you really get on a plane knowing that the electronics could get knocked out so easily???

Was the system designed to accomodate handovers from devices traveling at ~600 MPH?