Cellphone use

"Judah" wrote in message
. ..
tony roberts wrote in
news:indiacharlieecho-
15CF69.22341329122006@shawnews:



I haven't seen it myself, but I was told that there was a "MythBusters"
episode where the guys demonstrated that certain cell phones interfere
with
the ILS, causing the needle to deflect at least 50' to one side of the
runway.

I did see it. First, you have MUST keep in mind that the experiment,
while planned and controlled, was NOT realistic and the results were
inconclusive.
With that said, the receivers were cobbled together from off-the-shelf
from used avionics components. The system, under "normal" operation, with a
"normal" cell-phone did nothing to the glide slope or OBS. It was only when
the cobbled-up ILS was subjected to boosted energy on the cell-phone
frequency that some deviation occurred.
Note that the experiment ended up with a BUSTED! conclusion and caveats
from Jamie that the Mythbusters proved nothing.

"N2310D" wrote in news:%XEbh.17633$Uz.2268@trnddc05:

I did see it. First, you have MUST keep in mind that the
experiment, while planned and controlled, was NOT realistic and the
results were inconclusive.
With that said, the receivers were cobbled together from
off-the-shelf from used avionics components. The system, under
"normal" operation, with a "normal" cell-phone did nothing to the
glide slope or OBS. It was only when the cobbled-up ILS was
subjected to boosted energy on the cell-phone frequency that some
deviation occurred.
Note that the experiment ended up with a BUSTED! conclusion and
caveats from Jamie that the Mythbusters proved nothing.

Like I said, I hadn't seen the details.

I will say this - I used to have a Nextel phone with the walkie-talkie.
That thing interfered with everything from Computer Monitors to Doctor's
Office PA Systems. I have a Verizon phone now that is pretty benign, but I
never left that Nextel on when I was IFR - it wasn't worth the risk...

At the same time, the Nextel interfered with stuff that was at most 3'
away from me. In the pilot's seat, I could see a potential risk. I can't
imagine if I was sitting in the 1st row of a 737, let alone the 17th row,
anything I'm carrying will interfere with the GPS in the cockpit past the
galley, the toilet, the entry doors, and the piece of cardboard with the
metal bar they call a cabin door... I'm still pretty convinced that this
is at best a case of overprotection by the FAA to prevent risk from an
unknown (who knows what frequencies the phone companies will start
offerring service on?) and more likely a case of maintaining an outdated
rule because it allows Flight Attendents to do their briefing without
having to talk over a plane full of people on their cell phones...

Not much different than the "Seatbacks Upright" thing. Do you really think
it is a critical safety hazard that if the crew needs to evacuate the
passengers, the average person won't be able to navigate their way past
the 2" tilt of the seat in front of them. It rights itself when you push
it up...

tony roberts wrote:
It is an FCC rule because cellphone tower are designed to
pick up a limited number of calls and at altitude the towers
are over-loaded.

I don't understand this.
Consider that many new headsets actually have a cellphone interface.

and consider that here in Canada it is not illegal, and I use mine lots
- plugged right into my headset.
I don't understand how it could be legal here if it really did overload
towers. So what is the REAL reason?

Hmmmm . . . the plot thickens


I have heard that the real reason is that the towers are overloaded -

- with handovers.

The call has to be handed from tower to tower as the user
moves. The system was designed to cope
with walkers, people in cars, but not jets at 600mph.

I have no idea if the above is really true but it does make
some sort of sense to me.

On a related but unrelated topic -

One of the mysteries of life is that you can be in say London,
turn off a mobile phone, put it in a bag and go to Sydney.
When you get there you turn the phone on and if a few seconds later
your boss in Moscow calls you the call can be successfully routed
and your phone rings.

Ok I am flying my plane at 12,000 feet and the phone might talk to
several towers, thats frowned upon. Now, I hike about 2 miles and climb
the Grand Teton mountian to almost 14,000 feet, use my phone and it's
ok. I am getting confused again. G
Jim Macklin wrote:
It is an FCC rule because cellphone tower are designed to
pick up a limited number of calls and at altitude the towers
are over-loaded.



"pittss1c" wrote in message
...
|I know there are regs against cellphone usage in aircraft.
| I was wondering... has anyone ever known someone to get
busted?
| If so... what happened to them?
|
| Mike

wrote in message
oups.com...
Ok I am flying my plane at 12,000 feet and the phone might talk to
several towers, thats frowned upon. Now, I hike about 2 miles and climb
the Grand Teton mountian to almost 14,000 feet, use my phone and it's
ok. I am getting confused again. G

Well, a) you probably won't get very good phone reception at 12,000' AGL,
and b) cells are designed taking the terrain into account. Assuming you get
cell reception at the peak of Grand Teton Mt, it's because the cellular
network was designed with that location in mind, and specifically does not
have too many towers serving that location.

writes:

Ok I am flying my plane at 12,000 feet and the phone might talk to
several towers, thats frowned upon.

At least in GSM, this doesn't actually happen. The telephone rapidly
zeroes in one one base station, and stays with it until power
requirements dictate a handoff (I can't remember if the receiver or
the base station initiates the handoff). It doesn't talk continuously
with multiple base stations, even if multiple stations are in range
(and typically multiple stations _are_ in range, even on the ground).

--
Transpose mxsmanic and gmail to reach me by e-mail.

Jim Macklin wrote:
It is an FCC rule because cellphone tower are designed to
pick up a limited number of calls and at altitude the towers
are over-loaded.

Well the issue is that in analog cellular there are a finite
amount of talk channels and they use spatial diversity and
adaptively reducing power to reuse the channels in a metropolitan
area. A plane at altitude even at minimum power is heard equally
well over a wide number of base stations.

Of course, it's more involved now with digital modulations.