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Question About Cell Phone Calls

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posted on Feb, 18 2007 @ 11:58 AM
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Flight 93 was hijacked after both WTCs were hit, and was up in the air for over 25 minutes after Flight 77 hit the Pentagon. The passengers on Flight 93 were reported to have made numerous cell phone calls. These calls were critical in constructing the "heroes" version of the Flight 93 story.

Here's my question...

Why aren't there ANY reports of cell phone calls being made TO the passengers on Flight 93???

I'm thinking that if family members of Flight 93 passengers knew about WTC1, WTC2, and the Pentagon, and knew that they had loved ones flying out of the east coast that day, that at least somebody would have tried calling TO the passengers on Flight 93.

If the cell phones worked to call from the plane, wouldn't they be able to receive calls too?




posted on Feb, 18 2007 @ 01:20 PM
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IMO the entire thing is bogus. I have never been on a commercial flight other than right during takeoff or landing, that I have been able to get coverage, and I have tried many times.

To further that, I have attempted to get signal at very low altitudes in a private plane, and even then the signal was sporadic, and if I tried to make a call, I never had signal long enough that the call would comlete. The only thing I have been able to do in the air is send text messages.

To claim that these passengers had long conversations (even more than 10 seconds) is rediculous.

While each tower has a range of around 10 square miles, they are not set up to project their signal upward. The are setup to project the signal outward and at a slope. Think of it as a christmas tree in a sense. The area above the antenna that is receiving signal is quite faint, and a quite narrow radius.

If we want to say something like the plane was going around 300mph, that means given zero effect from head or tail winds, their ground speed is 300mph..of course give or take the ground speed for those effects mentioned.

If a tower has a a range of 10 square miles, and spacing is setup so that the tower footprints only slightly overlap, you are looking at a tower handoff ever 2 minutes in ideal conditions. That is, that the plane was flying level with, or below the height of the tower.

Now in absolute idea conditions like that, having a long conversation, and getting proper handoff might work.

But given the fact that when above the footprint of the towers you may have maximum footprint of 2-3 miles at 10,000 feet(still highly unlikely) Lets say these towers are spaced 18 miles apart, that means that at the least, you probably have 10 miles of dead zone between the towers.

So if you want to look at it with those numbers(which of course are not definitive, and just something general I am throwing out there).

Given 300mph at around 15-20k feet(well above the 10k feet in my example), you are probably looking at a maximum connection length of 10-15 seconds, even if you did manage to connect. Don't forget, this time factors in from the time you press send, to the time the party picks up the line. So in reality, probably about 6-8 seconds of conversation.

Now if you want to say they were flying low at 10k feet or less, you would be lucky to get 30 seconds of call, and again, this includes the time from call placement to answer.

In IDEAL conditions, we are looing at 15-20 seconds of total talk time.

Which I feel that the ideal conditions mentioned STILL are highly unlikely.

If you really want to put what I am saying to the test, go to your local airport, and ask for some sort of experience flight deal or whatever. For around $50 they will take you up for 30 second. Keep your phone on the whole time, and see how often you are able to get signal.

And then remember, that you are probably flying at around 100mph, and at an altitude of 2-3k feet, in an aircraft with far less sheilding than a commercial airliner.

If you think your reception is a little flaky there, just imagine going 300mph 20k feet up, and placing long calls.



posted on Feb, 18 2007 @ 02:33 PM
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The covereage on the GROUND in this area of PA is sketchy at best. My uncle lives near the top of a hillside about 20 miles from Shanksville and he gets no cell phone reception at all there.



posted on Feb, 18 2007 @ 10:54 PM
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Originally posted by nick7261
The covereage on the GROUND in this area of PA is sketchy at best. My uncle lives near the top of a hillside about 20 miles from Shanksville and he gets no cell phone reception at all there.


Here is some information:


By Brad Smith
September 24, 2001
c 2003, Reed Business Information, a division of Reed Elsevier Inc. All Rights Reserved.
When several passengers aboard the hijacked airliners made calls to family and spouses from their wireless phones on the now-infamous Sept. 11, it came as a surprise to many that the calls actually were completed.

Although airline passengers are warned against using their mobile phones in flight, it's fairly well-known that private airplane pilots often use regular cellular and PCS phones, even if it is illegal. Not quite as well-known, however, is that people have used their wireless phones to make surreptitious calls from the bathrooms of airliners.

The technology is there to support such airborne mobile connections. Take the Colorado company Aircell Inc., which uses FCC-approved equipment for wireless phone service.

But how does a terrestrial technology work in the sky?

First, altitude in itself is not a problem. Earthbound wireless phones can talk to base stations up to 10 miles away, depending on the terrain, while a typical passenger jet flies at an altitude of about six and a half miles. Since cell site antennas are configured to pick up signals horizontally and not from overhead, performance is usually compromised in calls from above. Nevertheless, cell sites can pick up signals from the air from great distances.

Toby Seay, vice president of national field operations for AT&T Wireless, says the technological limits to using a cell phone aboard a plane include the signal strength, potential signal inhibitors and "free space loss" as the signal gradually loses strength. The frequency used can make a difference, too. A signal using an 800 MHz cellular frequency can travel farther than a 1900 MHz PCS signal because of the different propagation characteristics of the two wavelengths.

The biggest problem with a phone signal sent from the air is that it can reach several different cell sites simultaneously. The signal can interfere with callers already using that frequency, and because there is no way for one cell site to hand off calls to another that is not adjacent to it, signals can become scrambled in the process. That's why wireless calls from jetliners don't last long, says Kathryn Condello, vice president of industry operations for CTIA. The network keeps dropping the calls, even if they are re-established later.

The phones on the back of the seats in most airplanes work similarly to a regular wireless phone. The major differences are that the antennas at the ground base stations are set up to pick up the signals from the sky, and there are far fewer stations handing off signals from one to another as a plane crosses overhead.

Also, Seay says, the airplane phones operated by AT&T Wireless and the GTE subsidiary of Verizon Communications send signals through wires to an antenna mounted on the outside of the plane. That is done to prevent interference with the plane's own radio communications, as well as to eliminate signal loss caused by the airplane's metal fuselage.


www.wirelessweek.com...

And:


An FCC study in 2000 found that cell-phone use aboard aircraft increases the number of blocked or dropped calls on the ground. That's because at high altitude, cellular signals are spread across several base stations, preventing other callers within range of those base stations from using the same frequencies.
www.washingtonpost.com...

And:


From this morning's New York Times: "According to industry experts, it is possible to use cell phones with varying success during the ascent and descent of commercial airline flights, although the difficulty of maintaining a signal appears to increase as planes gain altitude. Some older phones, which have stronger transmitters and operate on analog networks, can be used at a maximum altitude of 10 miles, while phones on newer digital systems can work at altitudes of 5 to 6 miles. A typical airline cruising altitude would be 35,000 feet, or about 6.6 miles."
www.slate.com...



posted on Feb, 19 2007 @ 12:10 AM
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Originally posted by CameronFox

Originally posted by nick7261
The covereage on the GROUND in this area of PA is sketchy at best. My uncle lives near the top of a hillside about 20 miles from Shanksville and he gets no cell phone reception at all there.


Here is some information...





Thanks for the info! I appreciate it!

However, I wasn't questioning whether the cell phones worked from the plane. I was just curious if there were any calls TO the passengers' cell phones from worried family members, etc.




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