Planes & Cell phones

Elwood Dowd wrote:

G.R. Patterson III wrote:
snip
Now, if you have one of those "personal communication systems" (AKA "PCS phones"),
you will not have this problem in the air. These phones use frequency sets in the 900
MhZ range, use different technology, and are legal to use in the air. Of course,

Are you sure PCS phones are legal in the air? As I understand it, this
is a hotly debated topic.

There is no US FCC regulation against using PCS phones (which do not use the old 800 Mhz
band) in the air. There IS a US FCC regulation against using Part 22 devices in the air,
which would include 800 Mhz AMPS service (traditional analog cellular) as well as newer
digital services in this same band. Sprint and T-Mobile are examples of wireless carriers
which are strictly PCS. Some companies may use both the 800 band and something else. (And
GSM is now starting to be used in the 800 Mhz band in the US, not just in the US 1900 Mhz
band.)

However, the terms of service for each carrier may prohibit airborne operation.

Thanks very much for a comprehensive answer! Not many of those are to
be found on usenet.

Lisa wrote:

There is no US FCC regulation against using PCS phones (which do not use the old 800 Mhz
band) in the air. There IS a US FCC regulation against using Part 22 devices in the air,
which would include 800 Mhz AMPS service (traditional analog cellular) as well as newer
digital services in this same band. Sprint and T-Mobile are examples of wireless carriers
which are strictly PCS. Some companies may use both the 800 band and something else. (And
GSM is now starting to be used in the 800 Mhz band in the US, not just in the US 1900 Mhz
band.)

However, the terms of service for each carrier may prohibit airborne operation.

Greg Copeland wrote:

The general theory on modern cell phones in flight, goes like this:
The FCC also has a ban because when you're in flight, you're always at
least 6-8 miles away from the nearest cell tower. You end up communicating
with too many towers and bogging down the network.

No, you could be right beside the nearest tower. In general, any tower within about
20 miles of you will be able to receive you when you're on the ground (unless
something's blocking the signal). To eliminate conflict between calls, towers that
are neighbors use different frequency sets. When you make a call, the control system
polls all of the towers that can "hear" you and tells the closest one to accept the
call. That tower tells your phone what frequency pair to use. After that, only that
tower can "hear" your phone. If you move too far away, the control system will poll
all the towers again and have your phone switch frequencies.

Unfortunately, there aren't enough radio frequencies to allow every tower to use a
unique set, so there will probably be several towers between 30 and 60 miles from you
that use the same set of frequencies that your phone is using. They can't hear you
'cause they're too far away.

Now take off. As soon as you get 500' up, some of these towers can hear your phone.
If these towers are using the same frequency pair for other calls that your phone is
using, your call will bleed into those conversations. Some hardware systems can
detect conflicts like this and have other phones change frequencies. This hardware,
however, will log the ID of the phone that's causing the trouble, and you may get a
service termination notice.

The system designers carefully design the network to prevent call conflict due to
things like skyscrapers. Skyscrapers rarely move, however.

George Patterson
This marriage is off to a shaky start. The groom just asked the band to
play "Your cheatin' heart", and the bride just requested "Don't come home
a'drinkin' with lovin' on your mind".

On Wed, 21 Apr 2004 03:43:32 +0000, G.R. Patterson III wrote:



Greg Copeland wrote:

The general theory on modern cell phones in flight, goes like this:
The FCC also has a ban because when you're in flight, you're always at
least 6-8 miles away from the nearest cell tower. You end up communicating
with too many towers and bogging down the network.

No, you could be right beside the nearest tower. In general, any tower within about
20 miles of you will be able to receive you when you're on the ground (unless
something's blocking the signal). To eliminate conflict between calls, towers that
are neighbors use different frequency sets. When you make a call, the control system
polls all of the towers that can "hear" you and tells the closest one to accept the
call. That tower tells your phone what frequency pair to use. After that, only that
tower can "hear" your phone. If you move too far away, the control system will poll
all the towers again and have your phone switch frequencies.

You exactly described what I less eloquently described elsewhere. What you described
qualifies as, "bogging down the network." It's not that you're "talking" on all these
towers. It's that you are using resources on all these towers at a very
high rate, as you move along, causing your call to jump from tower to
tower, in turn, causing the cycle to repeat over and over. Now, multiply
that with lots of other people using their phones on a plane, and I
think that clearly qualifies as, "You end up communicating with too many
towers and bogging down the network."


That's the complaint.

I'm tryint to speed-read all this excellent information, and I still don't
think I have an answer to my question:

By leaving my phone switched on, but *not making an outgoing call*, am I
doing no harm, or negligible harm, to the system?

Assume also that nobody calls me.

-- David Brooks

"G.R. Patterson III" wrote in message
...


Greg Copeland wrote:

The general theory on modern cell phones in flight, goes like this:
The FCC also has a ban because when you're in flight, you're always at
least 6-8 miles away from the nearest cell tower. You end up
communicating
with too many towers and bogging down the network.

No, you could be right beside the nearest tower. In general, any tower
within about
20 miles of you will be able to receive you when you're on the ground
(unless
something's blocking the signal). To eliminate conflict between calls,
towers that
are neighbors use different frequency sets. When you make a call, the
control system
polls all of the towers that can "hear" you and tells the closest one to
accept the
call. That tower tells your phone what frequency pair to use. After that,
only that
tower can "hear" your phone. If you move too far away, the control system
will poll
all the towers again and have your phone switch frequencies.

Unfortunately, there aren't enough radio frequencies to allow every tower
to use a
unique set, so there will probably be several towers between 30 and 60
miles from you
that use the same set of frequencies that your phone is using. They can't
hear you
'cause they're too far away.

Now take off. As soon as you get 500' up, some of these towers can hear
your phone.
If these towers are using the same frequency pair for other calls that
your phone is
using, your call will bleed into those conversations. Some hardware
systems can
detect conflicts like this and have other phones change frequencies. This
hardware,
however, will log the ID of the phone that's causing the trouble, and you
may get a
service termination notice.

The system designers carefully design the network to prevent call conflict
due to
things like skyscrapers. Skyscrapers rarely move, however.

George Patterson
This marriage is off to a shaky start. The groom just asked the band
to
play "Your cheatin' heart", and the bride just requested "Don't come
home
a'drinkin' with lovin' on your mind".

"David Brooks" wrote in message
...
I'm tryint to speed-read all this excellent information, and I still don't
think I have an answer to my question:

By leaving my phone switched on, but *not making an outgoing call*, am I
doing no harm, or negligible harm, to the system?

Assume also that nobody calls me.


Probably not. Digital phones have unique identifiers and are actually
supposed to be picked up by more than one tower at a time. If too many
towers pick up the phone then they electronically assign that phone to just
one tower and the others reject it. Since it is a digital stream, each
frequency can handle many cellular phones. It would be very difficult to bog
down the system with digital phones.

The problem is that the digital signals tend to be too weak, so the phone
frequently switches to analog when you start using it in an airplane. At the
very least, your phone will keep switching from one tower to another,
constantly searching even when you are not talking on it, and that will run
down the battery.

I recall reading somewhere that FCC regulations against using cellular
phones in flight do not apply to digital phones.

"C J Campbell" wrote in message
...

I recall reading somewhere that FCC regulations against using cellular
phones in flight do not apply to digital phones.



Nevertheless, I don't find any exception in this part:


§ 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.”

"C J Campbell" wrote in message
...

"C J Campbell" wrote in message
...

I recall reading somewhere that FCC regulations against using cellular
phones in flight do not apply to digital phones.



Nevertheless, I don't find any exception in this part:


§ 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.”

Of course, PCS phones are operated under Part 24 of the FCC regulations,
which have no prohibition against use in aircraft.

On Wed, 21 Apr 2004 08:59:34 -0700, "C J Campbell"
wrote:


"C J Campbell" wrote in message
...

I recall reading somewhere that FCC regulations against using cellular
phones in flight do not apply to digital phones.



Nevertheless, I don't find any exception in this part:


§ 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.”

Here's the FCC site on cellular telephones:

http://wireless.fcc.gov/services/cellular/

Here's the FCC site on PCS telephones:

http://wireless.fcc.gov/services/broadbandpcs/

The prohibition is in the first (Part 22). There is no corresponding
prohibition in the second (Part 24).

Don

C J Campbell wrote:

I recall reading somewhere that FCC regulations against using cellular
phones in flight do not apply to digital phones.

No, the regulations differential between PCS and cellular. Digital cellular phones
still create problmes.

George Patterson
This marriage is off to a shaky start. The groom just asked the band to
play "Your cheatin' heart", and the bride just requested "Don't come home
a'drinkin' with lovin' on your mind".