Great in-flight cell phone reception

JHW

JHW

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Jeff Wright
The stars or clouds or something were perfectly aligned the other night. Here's a screen shot from my iphone while it was getting emails and downloading foreflight weather graphics over 3G.
 

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You realize, you've posted evidence of violation of FCC regs, right?
 
JHW said:
Quote the reg. Last I heard the iphone is not an analog device.
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They still use the same frequencies as the old analog.

There is not a single device on the current commercial market that does not violate FCC regs when used in flight. I've seen one air-card that was specifically designed to not use those frequencies.

For regulations, let's look at 47 CFR:
§ 22.925 Prohibition on airborne operation of cellular telephones.
Cellular telephones installed in or carried aboard airplanes, balloons or any other type of aircraft must not be operated while such aircraft are airborne (not touching the ground). When any aircraft leaves the ground, all cellular telephones on board that aircraft must be turned off. The following notice must be posted on or near each cellular telephone installed in any aircraft:

“The use of cellular telephones while this aircraft is airborne is prohibited by FCC rules, and the violation of this rule could result in suspension of service and/or a fine. The use of cellular telephones while this aircraft is on the ground is subject to FAA regulations.”
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OK, but what is a "cellular telephone", and that's the whole "only applies to 800 MHz band" thing, right?

Now, let's look at the specs for the iPhone specifically:
http://www.apple.com/iphone/specs.html
GSM model A1428*: UMTS/HSPA+/DC-HSDPA (850, 900, 1900, 2100 MHz); GSM/EDGE (850, 900, 1800, 1900 MHz); LTE (Bands 4 and 17)
CDMA model A1429*: CDMA EV-DO Rev. A and Rev. B (800, 1900, 2100 MHz); UMTS/HSPA+/DC-HSDPA (850, 900, 1900, 2100 MHz); GSM/EDGE (850, 900, 1800, 1900 MHz); LTE (Bands 1, 3, 5, 13, 25)
GSM model A1429*: UMTS/HSPA+/DC-HSDPA (850, 900, 1900, 2100 MHz); GSM/EDGE (850, 900, 1800, 1900 MHz); LTE (Bands 1, 3, 5)
802.11a/b/g/n Wi-Fi (802.11n 2.4GHz and 5GHz)
Bluetooth 4.0 wireless technology
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The iPhone operates in the 800 MHz spectrum, and is thus prohibited.
 
JeffDG said:
They still use the same frequencies as the old analog.

There is not a single device on the current commercial market that does not violate FCC regs when used in flight. I've seen one air-card that was specifically designed to not use those frequencies.

For regulations, let's look at 47 CFR:


OK, but what is a "cellular telephone", and that's the whole "only applies to 800 MHz band" thing, right?

Now, let's look at the specs for the iPhone specifically:
http://www.apple.com/iphone/specs.html


The iPhone operates in the 800 MHz spectrum, and is thus prohibited.
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Is being on mean "operated". If so, we are all guilty at one time or another.
 
JHW said:
Quote the reg. Last I heard the iphone is not an analog device.
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From what I understood, the only violation is if you are operating under IFR. Looks like he is at a vfr altitude.
 
dell30rb said:
From what I understood, the only violation is if you are operating under IFR. Looks like he is at a vfr altitude.
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Can you cite a reg for that?

Only thing is that under IFR the owner or operator must determine that any portable electronic device does not interfere with aircraft systems.
 
I've determined my cell phone won't interfere.

I used to certify aircraft electrical components for a living.

Done.
 
bbchien said:
Be careful, Jeff.
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yeah I usually have it off, just forgot this time. I was surprised when I noticed it working. But I still turned it off right away, the battery won't last long if the cell signal is left on.
 
JHW said:
yeah I usually have it off, just forgot this time. I was surprised when I noticed it working. But I still turned it off right away, the battery won't last long if the cell signal is left on.
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Same here. In spite of my joking (mainly to give JeffDG a hard time), I actually always turn my phone off and instruct passengers to do so, primarily to make sure they have battery charge when they land.
 
Ted DuPuis said:
(mainly to give JeffDG a hard time)
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Achmed-The-Dead-Terrorist.gif
 
JeffDG said:
Well, FCC fines tend to be in the 5 figure range, so your call.
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Has anyone being fined for using their cellphone while airborne?. I don't think a cell phone company would report a customer to the FCC. After all obscene language over the airways is also a violation and there is a lot of that by cell phone users but never heard of anyone fined.

José
 
Piloto said:
Has anyone being fined for using their cellphone while airborne?. I don't think a cell phone company would report a customer to the FCC. After all obscene language over the airways is also a violation and there is a lot of that by cell phone users but never heard of anyone fined.

José
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The issue with airborne cell phones is the architecture of the 800 MHz infrastructure...you light up dozens of towers on the ground, and the companies can have significant performance issues as a result.

If you think they won't slap you down if you cause them an outage because you had your phone on, that's a risk you can feel free to take.
 
SO are you saying that being "On" is operating?
I guess I need to pick up a copy of 47CFR now...not on my to do list.:no:
 
flyingmoose said:
SO are you saying that being "On" is operating?
I guess I need to pick up a copy of 47CFR now...not on my to do list.:no:
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If it's transmitting, yes, that's "operating". If you turn the cell function off, then it won't transmit, that's fine. But absent specifically modified hardware (see the link above for discussion of a special Sprint aircard), you really don't have any control of what bands the device will use.
 
JeffDG said:
The issue with airborne cell phones is the architecture of the 800 MHz infrastructure...you light up dozens of towers on the ground, and the companies can have significant performance issues as a result.

If you think they won't slap you down if you cause them an outage because you had your phone on, that's a risk you can feel free to take.
Click to expand...

Cell phones do not transmit unless a phone call is initiated. Otherwise the battery would not last. To transmit the phone needs a handshake from a cell first. The problem while airborne is that the phone can not get a handshake due to the mutual interference at the phone due to it receiving multiple cells at the same time. So if you do not see the bars on the phone it will never transmit.

José
 
Piloto said:
Cell phones do not transmit unless a phone call is initiated. Otherwise the battery would not last. To transmit the phone needs a handshake from a cell first. The problem while airborne is that the phone can not get a handshake due to the mutual interference at the phone due to it receiving multiple cells at the same time. So if you do not see the bars on the phone it will never transmit.

José
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Absolutely and totally false.

For a practical demonstration of this, set your phone next to a set of amplified speakers (like computer speakers) and walk away. Some time within the next 15 minutes or so, you will hear a "chirping" noise through the speakers. This is your cell phone transmitting. Smart phones transmit much more often, as they are constantly sending and receiving data. But even "dumb" phones are regularly checking in with the network.

You are correct about the problem being due to locking on to multiple cellular towers at the same time, but incorrect about the rest.
 
I wonder how many millions of people have left their cell phones on flying on an airliner?
 
Alexb2000 said:
I wonder how many millions of people have left their cell phones on flying on an airliner?
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The FCC gave all of them a fine we'd have the deficit solved! ;)
 
So for reasons other than pilot distraction because he was talking on the cell phone or texting or checking his email or whatever when was the last time an accident occurred or a pilot missed a waypoint or something else bad happened to the plane because of a cell phone that was within the confines of the plane caused electrical(electronic) or other types of interference to the plane's instrumentation?

Just curious.

Doug
 
Piloto said:
Cell phones do not transmit unless a phone call is initiated. Otherwise the battery would not last. To transmit the phone needs a handshake from a cell first. The problem while airborne is that the phone can not get a handshake due to the mutual interference at the phone due to it receiving multiple cells at the same time. So if you do not see the bars on the phone it will never transmit.

José
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More utter and complete poppycock. GSM phones are always hunting for "mama" with powerful bursts, unless off. That's why they rapidly rundown, when on but out of range......
 
JeffDG said:
The issue with airborne cell phones is the architecture of the 800 MHz infrastructure...you light up dozens of towers on the ground, and the companies can have significant performance issues as a result.

If you think they won't slap you down if you cause them an outage because you had your phone on, that's a risk you can feel free to take.
Click to expand...

This. The phones won't interfere with your aircraft in a meaningful way, but any phone with 800 MHz active (that means all of your iPhones, android phones, blackberries, feature phones, LTE, 3G, 4g - they all have compatibility with 800 MHz) will completely futz with commercial infrastructure on the ground while turned on with network enabled.

That is why this is against FCC regs and not so much FAA regs.
 
ChrisK said:
This. The phones won't interfere with your aircraft in a meaningful way, but any phone with 800 MHz active (that means all of your iPhones, android phones, blackberries, feature phones, LTE, 3G, 4g - they all have compatibility with 800 MHz) will completely futz with commercial infrastructure on the ground while turned on with network enabled.
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Do you suppose the same things happens when someone has a cellphone on on the top floor of a tall building?

In urban areas where the cells are small, cell antennae are very directional and aimed below the horizon. That's one of the main reasons cell service doesn't work well up high in an airplane.
 
gismo said:
A quick read turned up enough erroneous statements in that article to make me discount the whole thing.
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If Lance says it, I believe it.
 
gismo said:
Do you suppose the same things happens when someone has a cellphone on on the top floor of a tall building?

In urban areas where the cells are small, cell antennae are very directional and aimed below the horizon. That's one of the main reasons cell service doesn't work well up high in an airplane.
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True nuff that they have a horizontal inverted cone radiation pattern, but I wouldn't go so far as to say it means that the FCC and carriers aren't worried enough about the problem to not legislate it :)
 
So, how exactly would the FCC enforce this rule?

And, furthermore, if it is a real problem, why don't we see issues near large commercial airports where you have many passengers who certainly do not turn off their phones?
 
JHW said:
The stars or clouds or something were perfectly aligned the other night. Here's a screen shot from my iphone while it was getting emails and downloading foreflight weather graphics over 3G.
Click to expand...

Be careful. That is a good way to get runaway endorphins.:lol:
 
ChrisK said:
I bet enough people follow the rule that it isn't a problem.
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I bet enough people don't and detection is difficult enough that it would be impractical to enforce and would cause a good bit of unrest if they tried.

Think about it - you get a $10,000 fine in the mail from the FCC because they claim you didn't turn your phone off while flying. You can bet I wouldn't pay it.
 
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