I read your attached but I see no validation of cell phones working in a
fuselage. The article is full of "could", "possibly" and "if" but no actual
validation to indicate it will function. Some reports indicate cell signals
work very intermittently in a fuselage. Many factors would be involved but
never for more than a few seconds at a time.

As the quote stated it was from a pilot. That should have not been confused
with another statement.

I believe that cells would work near the ground. The airspeed would be
slower, the windows (RF portholes) would align with the antennae better and
the antennae signals would be channeled more at the mobile cell handset.

OTOH: These hijacked flights would have been closer to the ground than a
regular flight so despite the logic and multiple persons telling us it can't
work the jury is still out for transmission capabilities. The cell switching
speed is still an unknown and I doubt the switching logic could handle cells
changing that fast. There are parameters in the switching logic that take
time to be sure, it is time, for the cell to switch frequencies and relock
with the next cell. I haven't found satisfactory evidence of this online,
yet, other than a 400ms blank out time. I believe I have experienced this
myself when switching cells.

I still maintain (as well as many others) the plane was shot down and the
cell phone conversations are lies to make the heroic story possible . No
other scenario would be possible.

-------------------
"Ed Huntress" wrote in message ...
Uh, Ok. So it doesn't happen. But it did happen. g Ask anyone who has used
one in a plane in the early days. Keep in mind that most of the use was, as
I said, soon before landing (and soon after takeoff). We aren't talking
about 30,000 feet.

I'm going to post a lengthy quote from Wikipedia at the bottom of this. If
you're interested, read it, and you'll see that cell phones did indeed work
on planes, when they were legal, and in the early days the systems were
analog, which is briefly mentioned. I have no idea how or if they work
today, because they haven't been allowed on flights I've taken for years.


Is this guy a communications engineer?


(From Wikipedia)

Cell tower channel re-use

The U.S. Federal Communications Commission (FCC) currently prohibits the use
of mobile telephones aboard any aircraft in flight. The reason given is that
mobile phone systems depend on channel reuse and operating a phone at
altitude may violate the fundamental assumptions that allow channel reuse to
work.

The FCC is also concerned that the use, or even non-use, of a powered cell
phone could cause disruption to the cell systems' towers and has banned
their use.[19]

Mobile telephones are intentionally designed with a low power output. A
tower is the center of a "cell" and due to attenuation with distance
(inverse square law) cell phone transmissions can usually be received only
weakly by towers in adjacent cells and not at all in cells farther away
(non-adjacent cells). This allows the channel used by any given phone to be
reused by other phones in non-adjacent cells. This principle allows tens or
hundreds of thousands of people to use their phones at the same time in a
given metropolitan area while using only a limited number of channels.

Channel reuse works because a mobile phone on the ground will only have one
"closest" tower that can possibly use a particular group of frequencies,
CDMA codes, or time slots. The software that manages the system assumes that
the signal from a phone on a particular tower can, on other towers, only be
"heard" at greatly reduced signal strength. The frequency, code, or time
slot used by the phone can therefore be reused by other phones on other
towers.

In the old analog cell system a channel was simply a frequency pair: There
were seven groups of 35 channels each and no two adjacent cells used the
same channel groups. Modern CDMA and TDMA systems are more complex: A
channel in TDMA is a frequency pair, and a time slot, and a channel in CDMA
is a spread spectrum key but the principle of channel reuse still applies.

If a mobile phone is operated from an aircraft in flight above a city these
assumptions ares no longer valid because the towers of numerous different
cells may be about equidistant from the phone. Multiple towers might assume
that the phone is under their control and the phone could be assigned a free
channel by one tower but could also be heard on other towers using the same
channel group. The channel might already be in use on those other towers and
could cause interference with existing calls. It is also possible that the
software controlling the towers could crash.[citation needed] Even if the
software can cope with hearing the same phone on multiple non-adjacent
towers the result at best is an overall decrease in system capacity.

An additional concern is the output power of the mobile handset. Because the
towers might be miles below the aircraft the phone might have to transmit at
its maximum power to be received. This will increase the risk of
interference with electronic equipment on the aircraft.