Cell phones in the air

I dunno guys.
It's not uncommon for a phone operated on the ground to be in reach of
several cells. A server arbitrates which of the available cells your call
should go through. I've also heard that it is difficult to get a signal if
you're very high because the antennae on the towers are optimized for
catching signals originating on the ground -- I've also heard stories
disputing this, included the 9-11 stories.
Bottom line--it's illegal and distracting so you shouldn't do it.
Why it's illegal in the US, I don't have a clue.


wrote in message
oups.com...
You ever drive behind someone on a cell phone call? ;-)

Stand back.. there will be others... here they come....

The technical issue is if you hit multiple cells at one time you may
have your account shut donw for a bit, looks like the cell was cloned
to them. And it may be illegal in your country.

Interesting article in this respect for the US based pilots at
http://www.macnewsworld.com/story/39038.html.

Generally the reception of GSM signals a dew degrees above the
horizontal is very poor. In the UK the signal drops in and out
repeatedly and a lot of the time a phone is non usable.

The generally accepted reason for this was that a phone would connect
to multiple cells and cause problems on the ground ( I doubt it since
the system was designed around mobile handsets anyway but I stand to be
corrected by an authoritative source ie: a systems engineer currently
working for a cellphone company! )

Ian

Roger Worden wrote:
I've seen a couple of references to someone not wanting us to use
cell
phones while gliding. I haven't seen the reason... what's the
rationale?

Hi,
on the antenna front I can make some comments.

The length of an antenna changes its radiation pattern. In simple terms the
1/4 wave that most of us use has a high angle of radiation, but presents a
50 ohm impedance to the radio (for which most of them are tuned)

It you go to a 1/2 wave (or even 5/8ths or 3/4 wave) you have a lower
angle of radiation and can effectively transmit further over the ground.
The only problem then is that you no longer have 50 ohm impedance
so need a "matching" network.

So the antennas used on mobile networks may well be low radiation types
which would find it difficult to "see" you at height. I certainly have
tried this out
in the air at my club in the UK and much over 2000 feet do not get a
signal.

Malcolm...

-.-


"For Example John Smith" wrote in message
...
I dunno guys.
It's not uncommon for a phone operated on the ground to be in reach of
several cells. A server arbitrates which of the available cells your call
should go through. I've also heard that it is difficult to get a signal
if
you're very high because the antennae on the towers are optimized for
catching signals originating on the ground -- I've also heard stories
disputing this, included the 9-11 stories.
Bottom line--it's illegal and distracting so you shouldn't do it.
Why it's illegal in the US, I don't have a clue.


wrote in message
oups.com...
You ever drive behind someone on a cell phone call? ;-)

Stand back.. there will be others... here they come....

The technical issue is if you hit multiple cells at one time you may
have your account shut donw for a bit, looks like the cell was cloned
to them. And it may be illegal in your country.

Earlier, Roger Worden wrote:

I've seen a couple of references to someone
not wanting us to use cell phones while
gliding. I haven't seen the reason...
what's the rationale?

Umm, because it's illegal? Here in the US at least.

Here's a link and quote from the Web site of the US Federal
Communications Commission:

http://ftp.fcc.gov/cgb/consumerfacts/cellonplanes.html

: Currently, cell phone users generally are permitted to use
: their phones before takeoff and after landing. FCC rules
: currently ban cell phone use after a plane has taken off
: because of potential interference to cellular phone
: networks on the ground. In addition, the Federal Aviation
: Administration (FAA) has rules prohibiting in-flight cell
: phone use because of potential interference to navigation
: and aircraft systems.

Thanks, and best regards to all

Bob K.
http://www.hpaircraft.com/hp-24

Roger Worden wrote:
I've seen a couple of references to someone not wanting us to use cell
phones while gliding. I haven't seen the reason... what's the rationale?


The most common answer seems to be that the
handset would "talk" to too many base stations
simultaneously. This is incorrect, as the
GSM protocol will not allow that. I'm sure the
CDMA protocol in the US does the same.

However, as the handset moves, the network
has to coordinate handovers between cells,
which increases network overhead. Most aircraft
are faster than cars, so they cause more handovers.

I'm sure the rule applies to gliders and baloons
simply because nobody bothered to make a distinction.

Kind regards,

Iwo

That was very useful. I knew about the IFR and carrier restrictions
in the FAA regs against cell use (and I think it even covers
taxiing) but I didn't know the FCC stuff. Thanks!

In article . com,
rromanATfrontiernetDOTnet wrote:

Roger Worden wrote:
I've seen a couple of references to someone not wanting us to use
cell
phones while gliding. I haven't seen the reason... what's the
rationale?

In the US there are FCC regulations prohibiting the use any aircraft -
from a FCC web page: Section 22.925 of the Commission's rules, 47 CFR
Part 22, provides that cellular telephones installed in, or carried
aboard airplanes, balloons, or any other type of aircraft, must not be
operated while the aircraft is off the ground. The FCC concern is
interference they may cause.



--

------------+
Mark J. Boyd

Iwo Mergler wrote:
Roger Worden wrote:

I've seen a couple of references to someone not wanting us to use cell
phones while gliding. I haven't seen the reason... what's the rationale?


The most common answer seems to be that the
handset would "talk" to too many base stations
simultaneously. This is incorrect, as the
GSM protocol will not allow that. I'm sure the
CDMA protocol in the US does the same.

However, as the handset moves, the network
has to coordinate handovers between cells,
which increases network overhead. Most aircraft
are faster than cars, so they cause more handovers.

I'm sure the rule applies to gliders and baloons
simply because nobody bothered to make a distinction.

I suspect that is right.

Apparently, the RAS community doesn't include any cellular system
engineers, or perhaps they have to take an oath of secrecy. This
question comes up amongst airplane people, too, and I've never seen a
reply anywhere from someone that actually is trained and knowledgeable
about the systems.

There certainly are a lot people high in the air making calls, like
pilots, hikers, and mountain climbers, but I've not heard of anybody
being chased down and fined. I do know my cell phone company has never
mentioned the subject in all the literature they send me, so I'm
guessing it's not a problem for them.

I think the biggest issue for glider pilots is the distraction of using
the phone.

--
Change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA

I heard recently on NPR the FAA is conducting studies on commercial
aircraft with cell phones and approval may come in a couple of years.
Clearly a good news bad news for those of us with frequent biz-travel
(an enforced respite from the phone is nice and who hasn't had enough
of overhearing someone yelling "can you hear me now").

If people fly gliders as poorly as they drive cars speaking on a cell
phone, that would be a bad thing. We have enough going on in the cock
pit without an additional distraction.

Chip F.

I wouldn't worry too much about lighting up cells. Your digital phone
has a pretty weak transmitter and your glider does a pretty good job of
attenuating signal in every direction that cannot see, especially if
its carbon. If you have a good reason to make a call and can do it
safely, why not. I've called 911 several times. And the retrieve office
on several occasions when I couldn't get a response by radio.

Legalities... well, laws are made for lots of reasons. The important
ones are enforced.

In article ,
Eric Greenwell wrote:

Apparently, the RAS community doesn't include any cellular system
engineers, or perhaps they have to take an oath of secrecy. This
question comes up amongst airplane people, too, and I've never seen a
reply anywhere from someone that actually is trained and knowledgeable
about the systems.

I wouldn't call myself a "cellular system engineer" but I've written
code that runs in the controlling computers for cell phone systems (both
GSM and CDMA), and I've spent time driving around measuring signal
strengths and data rates and diagnosing localized problems with those
things and with handoffs from one cell site to another.

In the CDMA system as used in the USA and by Telecom here in NZ), the
phone maintains up to three site in the "active set", plus half a dozen
more in the "candidate set". One of the sites in the active set is the
current pilot, which is the one that data is actually being sent
through. The phone has dedicated hardware (called a "finger") to
monitor and talk to each of the three active set members, and a single
extra set of hardware to scan the candidate set in turn, and decide
whethe to move one of them into the active set (replacing another one).
The phone will handoff to one of the other sites in the active set if
that signal gets enough better than the current pilot for long enough.

Each cell site has a set of up to twenty "neighbours" programmed into it
by the phone company. A new site can not get into the candidate set
unless it is a neighbour of one of the sites in the active set. Thus
sites too far away can not tie up resources in the phone or the network
(although if they have a strong signal they can appear as "noise" and
make it harder to talk to nearby but weak sites).

There are several other mechanisms to prevent far-off sites from talking
to a phone. One is the "search window". Typically cell sites in a city
are set up to reject communication attempts from phones that are more
than, say, 20 "chips" (about 5 km) away. Also the antennas themselves
will often have downtilt (either mechanical or electronic or both)
applied so that the main beam can't be picked up from too far away.

All the above applies to the newer digital systems (CDMA, though GSM is
similar) which should not be troubled at all by a few people in
slow-moving gliders. The older analogue systems were far less
sophisticated and could be much more easily swamped. Phones travelling
at 1000 km/h would do interesting things as there is usually, for
example, around a three second delay before handing off to a cell site
with a better signal.

--
Bruce | 41.1670S | \ spoken | -+-
Hoult | 174.8263E | /\ here. | ----------O----------